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Thoracic Endovascular Aortic Repair

Update on Indications and Guidelines

      Keywords

      Key points

      • Thoracic endovascular aortic repair (TEVAR) was initially developed as a treatment for descending thoracic aortic aneurysms in patients deemed unfit for conventional open surgical repair.
      • Since then, improvements in endograft design, delivery devices and technical innovations such as hybrid procedures and fenestrated and branched grafts, have allowed endovascular repair to be applied to other thoracic aortic pathologies.
      • The dramatic expansion of TEVAR activity has necessitated a better definition for the indications, contraindications, and limitations of this new novel technology.

      Introduction

      In 1953, DeBakey and Cooley
      • DeBakey M.E.
      • Cooley D.A.
      Successful resection of aneurysm of the thoracic aorta and replacement by graft.
      performed the first successful resection of a fusiform aortic aneurysm with a synthetic graft replacement.
      • DeBakey M.E.
      • Cooley D.A.
      Successful resection of aneurysm of the thoracic aorta and replacement by graft.
      • Findeiss L.K.
      • Cody M.E.
      Endovascular repair of the thoracic aortic aneurysms.
      Since then, open surgical repair of the descending thoracic aorta with resection and graft interposition has become the gold standard in the treatment of descending thoracic aortic aneurysms (DTAAs).
      • Findeiss L.K.
      • Cody M.E.
      Endovascular repair of the thoracic aortic aneurysms.
      • Adams J.D.
      • Garcia L.M.
      • Kern J.A.
      Endovascular repair of the thoracic aorta.
      Despite significant medical advances, which have allowed operative mortality to decrease to as low as 2.9% in specialized centers, conventional open surgical repair (OSR) is generally associated with substantial morbidity and mortality in a patient population that is often aged and medically debilitated.
      • Findeiss L.K.
      • Cody M.E.
      Endovascular repair of the thoracic aortic aneurysms.
      • Adams J.D.
      • Garcia L.M.
      • Kern J.A.
      Endovascular repair of the thoracic aorta.
      • Achneck H.E.
      • Rizzo J.A.
      • Tranquilli M.
      • et al.
      Safety of thoracic aortic surgery in the present era.
      As a result, with the advent of endoluminal technology, thoracic endovascular aortic repair (TEVAR) has emerged as a less invasive treatment modality for patients considered to be unfit for OSR, with a reduction in both morbidity and mortality.

      Available devices

      In 2005, the GORE TAG graft (W. L. Gore & Associates Inc, Flagstaff, AZ)
      • Makaroun M.S.
      • Dillavou E.D.
      • Kee S.T.
      • et al.
      Endovascular treatment of thoracic aortic aneurysms: results of the phase II multicenter trial of the GORE TAG thoracic endoprosthesis.
      was approved by the US Food and Drug Administration (FDA) to treat DTAAs and subsequently, in 2008, the Zenith TX2 TAA Endovascular Graft (Cook Inc, Bloomington, IN)
      • Matsumura J.S.
      • Cambria R.P.
      • Dake M.D.
      • et al.
      International controlled clinical trial of thoracic endovascular aneurysm repair with the Zenith TX2 endovascular graft: 1-year results.
      and the Talent Thoracic Stent Graft System (Medtronic Vascular, Santa Rosa, CA)
      • Fairman R.M.
      • Criado F.
      • Farber M.
      • et al.
      Pivotal results of the Medtronic vascular talent thoracic stent graft system: the VALOR trial.
      were approved for the treatment of DTAAs and penetrating atherosclerotic aortic ulcers.
      • Adams J.D.
      • Garcia L.M.
      • Kern J.A.
      Endovascular repair of the thoracic aorta.
      The Valiant Captivia Thoracic Stent Graft (Medtronic Inc, Minneapolis, MN) and the redesigned Conformable GORE TAG Device (Gore & Associates) have been recently approved (2012) by the FDA for the endovascular repair of isolated lesions (excluding dissections) of the descending segment of the thoracic aorta. This expanded indication includes the treatment of blunt traumatic thoracic aortic injuries. A fifth thoracic device, the Relay stent graft (Bolton Medical Inc, Sunrise, FL) has completed pivotal trial enrollment and awaits regulatory approval.
      Hybrid procedures, improvements in endograft design and delivery devices, and fenestrated and branched grafts have allowed TEVAR to be applied to other thoracic aortic pathologies in an off-label manner. Examples include thoracoabdominal aortic aneurysm (TAAA), aortic arch aneurysm, aortic dissection, and ruptured DTAA.
      • Adams J.D.
      • Garcia L.M.
      • Kern J.A.
      Endovascular repair of the thoracic aorta.

      Argalious M. Endovascular aortic repair in the descending thoracoabdominal aorta [abstract 322]. In: Programs and abstracts of the American Society of Anesthesiologists’ Annual Meeting. Chicago, IL, October 15–17, 2011. p. 1–9.

      • Grabenwoger M.
      • Alfonso F.
      • Bachet J.
      • et al.
      Thoracic endovascular aortic repair (TEVAR) for the treatment of aortic diseases: a position statement from the European Association for Cardio-Thoracic Surgery (EACTS) and the European Society of Cardiology (ESC), in collaboration with the European Association of Percutaneous Cardiovascular Interventions (EAPCI).
      Fenestrated and branched endografts have been developed as a minimally invasive, totally endovascular alternative for the treatment of complex thoracic aortic aneurysms in high-risk patients. These devices are custom made to fit the specific anatomic requirements of each patient. Fenestrated grafts have openings (fenestrations) within the stent-graft fabric to accommodate visceral arteries. Branched grafts have separate smaller side-arm grafts sutured to the basic stent graft for deployment into an artery to preserve flow into it. Another approach places a self-expanding stent graft through the opening of a fenestrated graft.

      Argalious M. Endovascular aortic repair in the descending thoracoabdominal aorta [abstract 322]. In: Programs and abstracts of the American Society of Anesthesiologists’ Annual Meeting. Chicago, IL, October 15–17, 2011. p. 1–9.

      • Grabenwoger M.
      • Alfonso F.
      • Bachet J.
      • et al.
      Thoracic endovascular aortic repair (TEVAR) for the treatment of aortic diseases: a position statement from the European Association for Cardio-Thoracic Surgery (EACTS) and the European Society of Cardiology (ESC), in collaboration with the European Association of Percutaneous Cardiovascular Interventions (EAPCI).

      Preoperative imaging and evaluation

      Contrast-enhanced computed tomographic angiography (CTA) or magnetic resonance angiography (MRA) of the chest, abdomen, and pelvis with 3-dimensional (3D) reformatting is performed preoperatively.
      • Adams J.D.
      • Garcia L.M.
      • Kern J.A.
      Endovascular repair of the thoracic aorta.
      Imaging can identify patients with aortic anatomy that either precludes the use of stent grafts, requires the use of custom fenestrated or branched stent grafts, or necessitates the use of staged and/or hybrid procedures.
      • Findeiss L.K.
      • Cody M.E.
      Endovascular repair of the thoracic aortic aneurysms.
      Imaging is also used to determine the diameter and length of the endograft(s), and the most appropriate site for vascular access.
      The following must be determined: (1) conformation of the aortic arch, (2) location of origins of great vessels relative to the proximal margin of the aneurysm, (3) tortuosity of the descending aorta along its entire length, (4) location of origins of mesenteric vessels relative to the distal margin of the aneurysm, (5) comparative diameters of proximal and distal landing zones, (6) tortuosity and diameter of the iliofemoral arteries, and (7) presence of abdominal aortic graft. In patients who may require coverage of the left subclavian artery, a CTA of the head and neck is obtained to establish the presence of a patent circle of Willis and a nondominant left vertebral artery.
      • Findeiss L.K.
      • Cody M.E.
      Endovascular repair of the thoracic aortic aneurysms.
      • Adams J.D.
      • Garcia L.M.
      • Kern J.A.
      Endovascular repair of the thoracic aorta.

      Surgical considerations for specific hybrid procedures

      A hybrid procedure is a combination of an open surgical approach and an endovascular stenting procedure that uses extra-anatomic bypass techniques to expand the “anatomic” suitability for deployment of stent grafts into zones 0, 1, and 2.
      • Adams J.D.
      • Garcia L.M.
      • Kern J.A.
      Endovascular repair of the thoracic aorta.

      Argalious M. Endovascular aortic repair in the descending thoracoabdominal aorta [abstract 322]. In: Programs and abstracts of the American Society of Anesthesiologists’ Annual Meeting. Chicago, IL, October 15–17, 2011. p. 1–9.

      • Grabenwoger M.
      • Alfonso F.
      • Bachet J.
      • et al.
      Thoracic endovascular aortic repair (TEVAR) for the treatment of aortic diseases: a position statement from the European Association for Cardio-Thoracic Surgery (EACTS) and the European Society of Cardiology (ESC), in collaboration with the European Association of Percutaneous Cardiovascular Interventions (EAPCI).
      Hybrid procedures can be either staged or done concurrently.

      Argalious M. Endovascular aortic repair in the descending thoracoabdominal aorta [abstract 322]. In: Programs and abstracts of the American Society of Anesthesiologists’ Annual Meeting. Chicago, IL, October 15–17, 2011. p. 1–9.

      Rerouting of supra-aortic branches by transposition or bypass enables endovascular treatment of the aortic arch and proximal descending aorta without the need for aortic cross-clamping, cardiopulmonary bypass (CPB), and/or hypothermic circulatory arrest.
      • Adams J.D.
      • Garcia L.M.
      • Kern J.A.
      Endovascular repair of the thoracic aorta.

      Argalious M. Endovascular aortic repair in the descending thoracoabdominal aorta [abstract 322]. In: Programs and abstracts of the American Society of Anesthesiologists’ Annual Meeting. Chicago, IL, October 15–17, 2011. p. 1–9.

      • Grabenwoger M.
      • Alfonso F.
      • Bachet J.
      • et al.
      Thoracic endovascular aortic repair (TEVAR) for the treatment of aortic diseases: a position statement from the European Association for Cardio-Thoracic Surgery (EACTS) and the European Society of Cardiology (ESC), in collaboration with the European Association of Percutaneous Cardiovascular Interventions (EAPCI).
      Zones of proximal aortic endograft attachment sites are shown in Fig. 1.
      • Adams J.D.
      • Garcia L.M.
      • Kern J.A.
      Endovascular repair of the thoracic aorta.
      • Criado F.
      • Abul-Khoudoud O.
      • Domer G.
      • et al.
      Endovascular repair of the thoracic aorta: lessons learned.
      Figure thumbnail gr1
      Fig. 1The zones of proximal aortic endograft attachment sites.
      (Adapted from Criado F, Abul-Khoudoud O, Domer G, et al. Endovascular repair of the thoracic aorta: lessons learned. Ann Thorac Surg 2005;80:857–63; with permission.)

      Left Subclavian Artery Coverage and Revascularization

      A proximal landing zone that requires coverage of the left subclavian artery (LSCA) (eg, zones 0, 1, and 2) occurs in 35% to 41% of cases.
      • Feezor R.J.
      • Martin T.D.
      • Hess P.J.
      • et al.
      Risk factors for perioperative stroke during thoracic endovascular aortic repairs (TEVAR).
      LSCA revascularization is accomplished by left common carotid artery to LSCA bypass (Fig. 2) or LSCA transposition.
      • Criado F.J.
      • Barnatan M.F.
      • Rizk Y.
      • et al.
      Technical strategies to expand stent-graft applicability in the aortic arch and proximal descending thoracic aorta.
      However, the need for preoperative LSCA revascularization has been the subject of much debate. Some surgeons choose expectant management, with LSCA revascularization for postocclusion symptoms after TEVAR, whereas others advocate routine LSCA revascularization.
      • Findeiss L.K.
      • Cody M.E.
      Endovascular repair of the thoracic aortic aneurysms.
      • Adams J.D.
      • Garcia L.M.
      • Kern J.A.
      Endovascular repair of the thoracic aorta.
      • Rizvi A.Z.
      • Murad M.H.
      • Fairman R.M.
      • et al.
      The effect of left subclavian artery coverage on morbidity and mortality in patients undergoing endovascular thoracic aortic interventions: a systematic review and meta-analysis.
      • Matsumura J.S.
      • Lee W.A.
      • Mitchell R.S.
      • et al.
      The Society for Vascular Surgery Practice Guidelines: management of the left subclavian artery with thoracic endovascular aortic repair.
      Others use selective LSCA revascularization before TEVAR, based on patient-specific anatomic considerations, particularly when there is a left dominant vertebral artery, a patent left internal mammary coronary artery bypass graft or an occluded right vertebral artery, and in patients considered at high risk for paraplegia.
      • Findeiss L.K.
      • Cody M.E.
      Endovascular repair of the thoracic aortic aneurysms.
      • Adams J.D.
      • Garcia L.M.
      • Kern J.A.
      Endovascular repair of the thoracic aorta.
      • Feezor R.J.
      • Martin T.D.
      • Hess P.J.
      • et al.
      Risk factors for perioperative stroke during thoracic endovascular aortic repairs (TEVAR).
      • Rizvi A.Z.
      • Murad M.H.
      • Fairman R.M.
      • et al.
      The effect of left subclavian artery coverage on morbidity and mortality in patients undergoing endovascular thoracic aortic interventions: a systematic review and meta-analysis.
      • Matsumura J.S.
      • Lee W.A.
      • Mitchell R.S.
      • et al.
      The Society for Vascular Surgery Practice Guidelines: management of the left subclavian artery with thoracic endovascular aortic repair.
      Figure thumbnail gr2
      Fig. 2Left common carotid to left subclavian artery (LSCA) bypass. The proximal LSCA has been ligated to prevent retrograde type II endoleak.
      (From Criado FJ, Barnatan MF, Rizk Y, et al. Technical strategies to expand stent-graft applicability in the aortic arch and proximal descending thoracic aorta. J Endovasc Ther 2002;(9 Suppl 2):II32–8; with permission.)
      In an attempt to offer evidence-based guidelines for the management of patients requiring LSCA coverage, a meta-analysis and systematic review of the literature was conducted by the Society for Vascular Surgery (SVS), which discovered that the overall quality of evidence was very low.
      • Rizvi A.Z.
      • Murad M.H.
      • Fairman R.M.
      • et al.
      The effect of left subclavian artery coverage on morbidity and mortality in patients undergoing endovascular thoracic aortic interventions: a systematic review and meta-analysis.
      • Matsumura J.S.
      • Lee W.A.
      • Mitchell R.S.
      • et al.
      The Society for Vascular Surgery Practice Guidelines: management of the left subclavian artery with thoracic endovascular aortic repair.
      The SVS issued 3 recommendations
      • Matsumura J.S.
      • Lee W.A.
      • Mitchell R.S.
      • et al.
      The Society for Vascular Surgery Practice Guidelines: management of the left subclavian artery with thoracic endovascular aortic repair.
      :
      • 1.
        In patients who need elective TEVAR whereby achievement of a proximal seal necessitates coverage of the LSCA, routine preoperative revascularization is recommended despite the very low-quality evidence (Grade 2, level of evidence C).
      • 2.
        In selected patients who have an anatomy that compromises perfusion to critical organs, routine preoperative LSCA revascularization is strongly recommended despite the very low-quality evidence (Grade 1, level of evidence C).
      • 3.
        In patients who need very urgent TEVAR for life-threatening acute aortic syndromes whereby achievement of a proximal seal necessitates coverage of the LSCA, revascularization should be individualized and addressed expectantly based on anatomy, urgency, and availability of surgical expertise (Grade 2, level of evidence C).

      Hybrid Elephant-Trunk Procedure

      In patients who have transverse aortic arch aneurysms with no adequate proximal landing zone but an adequate distal landing zone, a first-stage total arch replacement is performed to create a proximal landing zone using CPB and deep hypothermic circulatory arrest. This procedure is followed at a later setting with the second-stage endovascular repair using the elephant-trunk graft as the proximal landing zone.

      Argalious M. Endovascular aortic repair in the descending thoracoabdominal aorta [abstract 322]. In: Programs and abstracts of the American Society of Anesthesiologists’ Annual Meeting. Chicago, IL, October 15–17, 2011. p. 1–9.

      Frozen Elephant-Trunk Technique

      This technique is a single-stage procedure with conventional surgical repair of the ascending aorta and the aortic arch combined with open antegrade stent grafting of the descending aorta, during circulatory arrest.
      • Grabenwoger M.
      • Alfonso F.
      • Bachet J.
      • et al.
      Thoracic endovascular aortic repair (TEVAR) for the treatment of aortic diseases: a position statement from the European Association for Cardio-Thoracic Surgery (EACTS) and the European Society of Cardiology (ESC), in collaboration with the European Association of Percutaneous Cardiovascular Interventions (EAPCI).

      Aortic Visceral Debranching Procedures

      Aortic visceral debranching procedures allow for endovascular stenting of TAAAs that involve the visceral arteries.

      Argalious M. Endovascular aortic repair in the descending thoracoabdominal aorta [abstract 322]. In: Programs and abstracts of the American Society of Anesthesiologists’ Annual Meeting. Chicago, IL, October 15–17, 2011. p. 1–9.

      Debranching procedures or extra-anatomic bypasses can revascularize the visceral and renal arteries from the iliac arteries in a retrograde fashion or from the descending thoracic aorta above the aneurysm being treated. Such a procedure is followed by stent grafting of the aneurysm either at the same setting as the debranching procedure or as a first part of a “staged” procedure. A 2-stage procedure is associated with a decreased incidence of spinal cord ischemia (SCI) and renal dysfunction.
      • Bischoff M.S.
      • Di Luozzo G.
      • Griepp E.B.
      • et al.
      Spinal cord preservation in thoracoabdominal aneurysm repair.
      • Lin P.H.
      • Kougias P.
      • Bechara C.F.
      • et al.
      Clinical outcome of staged versus combined treatment approach of hybrid repair of thoracoabdominal aortic aneurysm with visceral vessel debranching and aortic endograft exclusion.
      The reason for the decreased incidence of SCI is that a 2-stage procedure avoids extensive segmental artery sacrifice, as occurs in a single-stage procedure.
      • Bischoff M.S.
      • Di Luozzo G.
      • Griepp E.B.
      • et al.
      Spinal cord preservation in thoracoabdominal aneurysm repair.

      Indications and potential uses for TEVAR in thoracic aortic disease

      Descending Thoracic Aortic Aneurysms

      The incidence of thoracic aortic aneurysms (TAAs) is 10.4 per 100,000 person-years.
      • Findeiss L.K.
      • Cody M.E.
      Endovascular repair of the thoracic aortic aneurysms.
      Aneurysms of the descending thoracic aorta account for approximately 30% to 40% of all TAAs, and their prevalence has tripled over the last 2 decades.
      • Hiratzka L.F.
      • Bakris G.L.
      • Beckman J.A.
      • et al.
      2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
      • Coady M.A.
      • Ikonomidis J.S.
      • Cheung A.T.
      • et al.
      Surgical management of descending thoracic aortic disease: open and endovascular approaches: a scientific statement from the American Heart Association.
      The disease process is virulent but indolent because it typically grows slowly at an approximate rate of 0.19 cm/y.
      • Coady M.A.
      • Ikonomidis J.S.
      • Cheung A.T.
      • et al.
      Surgical management of descending thoracic aortic disease: open and endovascular approaches: a scientific statement from the American Heart Association.
      The annual risk of rupture, dissection, or death is 14.1% in patients with aneurysms larger than 6 cm, compared with 6.5% for aneurysms between 5 and 6 cm.
      • Findeiss L.K.
      • Cody M.E.
      Endovascular repair of the thoracic aortic aneurysms.
      The 5-year survival rate for patients with TAAs treated nonsurgically is 13% to 19.2%, and 60% to 79% for those treated surgically.
      • Hiratzka L.F.
      • Bakris G.L.
      • Beckman J.A.
      • et al.
      2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
      • Coady M.A.
      • Ikonomidis J.S.
      • Cheung A.T.
      • et al.
      Surgical management of descending thoracic aortic disease: open and endovascular approaches: a scientific statement from the American Heart Association.
      • Gutsche J.T.
      • Szeto W.
      • Cheung A.T.
      Endovascular stenting of thoracic aortic aneurysm.
      • Svensson L.G.
      • Kouchoukos N.T.
      • Miller D.C.
      • et al.
      Expert consensus document on the treatment of descending thoracic aortic disease using endovascular stent-grafts.

      Open repair

      Contemporary results of open repairs of elective DTAAs indicate early mortality rates of 4.8%, paraplegia rates of 3.4%, stroke rates of 2.7%, respiratory failure rates of 9.2%, and renal failure rates of 2.9%. Three-, 5-, and 10-year survival estimates are 72%, 63%, and 38%, respectively.
      • Svensson L.G.
      • Kouchoukos N.T.
      • Miller D.C.
      • et al.
      Expert consensus document on the treatment of descending thoracic aortic disease using endovascular stent-grafts.

      Endovascular repair

      The current guidelines from the Society of Thoracic Surgeons (STS) suggest TEVAR for DTAAs when the aortic diameter is greater than 5.5 cm (Class IIa recommendation, level of evidence B, when the patient has significant comorbidity; Class IIb recommendation, level of evidence C, when the patient has no significant comorbidity).
      • Svensson L.G.
      • Kouchoukos N.T.
      • Miller D.C.
      • et al.
      Expert consensus document on the treatment of descending thoracic aortic disease using endovascular stent-grafts.
      When the aortic diameter is less than 5.5 cm, the STS guidelines advise against TEVAR (Class III recommendation, level of evidence C).
      • Svensson L.G.
      • Kouchoukos N.T.
      • Miller D.C.
      • et al.
      Expert consensus document on the treatment of descending thoracic aortic disease using endovascular stent-grafts.
      The current American College of Cardiology/American Heart Association (ACC/AHA) guidelines suggest TEVAR for DTAAs larger than 5.5 cm, when technically feasible (ACC/AHA Class I recommendation, level of evidence B).
      • Hiratzka L.F.
      • Bakris G.L.
      • Beckman J.A.
      • et al.
      2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
      A prospective, nonrandomized, multicenter trial compared 140 patients who underwent endograft exclusion with 94 historical or concurrent patients who underwent open repair. Of the 140 patients, 137 had successful implantation of the endograft. Patients who underwent TEVAR had a significant reduction in perioperative mortality (2.1% vs 11.7%), respiratory failure (4% vs 20%), renal insufficiency (1% vs 13%), SCI (3% vs 14%), mean length of stay in the intensive care unit (2.6 ± 14.6 vs 5.2 ± 7.2 days), and overall hospital stay (7.4 ± 17.7 vs 14.4 ± 12.8 days). No significant difference was observed in the rate of stroke between the 2 groups (3.6% for the TEVAR group and 4.3% for the open repair group). However, after 2 years of follow-up, there was a 9% incidence of endoleaks and 3 reinterventions associated with TEVAR versus OSR. There was no difference in overall mortality between the 2 groups, at 2 years. At 5 years, the 2 groups differed in their aneurysm-related mortality rates (2.8% for TEVAR and 11.7% for open repair) but not in their rates of all-cause mortality (32% and 33%, respectively).
      • Bavaria J.E.
      • Appoo J.J.
      • Makaroun M.S.
      • Gore TAG Investigators
      • et al.
      Endovascular stent grafting versus open surgical repair of descending thoracic aortic aneurysms in low-risk patients: a multicenter comparative trial.
      • Cao C.Q.
      • Bannon P.G.
      • Shee R.
      • et al.
      Thoracic endovascular aortic repair-indications and evidence.

      Summary

      TEVAR (Fig. 3) is less invasive and is associated with a decrease in perioperative morbidity and mortality when compared with OSR. Lifelong surveillance remains mandatory. However, although OSR is more invasive, it is definitive, with well-defined long-term follow-up in comparison with TEVAR.
      Figure thumbnail gr3
      Fig. 3Aortic angiograms. (Left) A prerepair angiogram after LSCA to carotid transfer. Shown are aneurysm (single arrow), LSCA stump (double arrow), and LSCA to carotid transfer (triple arrow). (Right) Postrepair angiography.
      (From Gutsche JT, Szeto W, Cheung Al. Endovascular stenting of thoracic aortic aneurysm. Anesthesiol Clin 2008;26:481–99.)

      Ruptured Descending Thoracic Aneurysms

      The incidence of ruptured DTAAs (rDTAAs) is 3.5 per 100,000 person-years, and is the cause of death in 51% of patients with degenerative aneurysms. Mortality from ruptured aneurysms approaches 100% without treatment, with almost 60% of patients dying in the prehospital environment.
      • Findeiss L.K.
      • Cody M.E.
      Endovascular repair of the thoracic aortic aneurysms.
      Recently, TEVAR has been shown to be an alternative to open repair of rDTAAs.
      Jonker and colleagues
      • Jonker F.H.
      • Trimarchi S.
      • Verhagen H.J.
      • et al.
      Meta-analysis of open versus endovascular repair for ruptured descending thoracic aortic aneurysm.
      published a meta-analysis comparing the outcomes of TEVAR and open repair in patients with rDTAAs. One hundred forty-three (64%) were treated with TEVAR and 81 (36%) with open repair. Mean age was 70 ± 5.6 years. The 30-day mortality was 19% for patients treated with TEVAR for rDTAAs compared with 33% for patients treated with open repair (P = .016). The 30-day occurrence rates of myocardial infarction (11.1% vs 3.5%; P<.05), stroke (10.2% vs 4.1%; P = .117), and paraplegia (5.5% vs 3.1%; P = .405) were increased after open repair in comparison with TEVAR. However, long-term follow-up revealed 5 aneurysm-related deaths in the TEVAR group after 30 days (median follow-up of 17 ± 10 months), whereas no patients died of aneurysm-related causes in the open group after the same period. The estimated aneurysm-related survival at 3 years after TEVAR was 70.6%.
      • Cao C.Q.
      • Bannon P.G.
      • Shee R.
      • et al.
      Thoracic endovascular aortic repair-indications and evidence.
      • Jonker F.H.
      • Trimarchi S.
      • Verhagen H.J.
      • et al.
      Meta-analysis of open versus endovascular repair for ruptured descending thoracic aortic aneurysm.

      Summary

      Endovascular repair of rDTAAs is associated with a lower 30-day mortality rate and a lower risk of death, myocardial infarction, stroke, and paraplegia when compared with OSR, and it appears to be the treatment of choice in anatomically suitable patients with a rDTAA.

      Blunt Traumatic Thoracic Aortic Injury

      Thoracic aortic injury is the second most common cause of death after blunt trauma among patients with major traumatic injuries. It typically occurs with high-speed, deceleration-type injuries, and 80% to 90% of victims die at the scene of the accident. Without surgical intervention, 30% to 50% of initial survivors will die within the first 24 hours. The majority of blunt traumatic thoracic aortic injuries (BTTAIs) occur at the aortic isthmus (80%–90%) just distal to the LSCA.
      • Nicolaou G.
      Endovascular treatment of blunt traumatic thoracic aortic injury.
      Traditional open repair has been associated with an average mortality rate of 18% to 28% and a paraplegia rate of 2.3% to 14%.
      • Coady M.A.
      • Ikonomidis J.S.
      • Cheung A.T.
      • et al.
      Surgical management of descending thoracic aortic disease: open and endovascular approaches: a scientific statement from the American Heart Association.
      Recently, several meta-analyses have shown improved outcomes with TEVAR when compared with open repair for BTTAI. The aortic injury is classified into 4 grades: grade 1 (intimal injury), grade 2 (intramural hematoma), grade 3 (pseudoaneurysm), and grade 4 (aortic rupture). Intervention is needed for grades 2 to 4, whereas conservative treatment (blood pressure control and follow-up imaging) is reserved for grade 1.
      • Azizzadeh A.
      • Keyhani K.
      • Miller 3rd, C.C.
      • et al.
      Blunt traumatic aortic injury: initial experience with endovascular repair.
      A meta-analysis conducted by Tang and colleagues
      • Tang G.L.
      • Tehrani H.Y.
      • Usman A.
      • et al.
      Reduced mortality, paraplegia, and stroke with stent graft repair of blunt aortic transections: a modern meta-analysis.
      analyzed 699 procedures (TEVAR 370; open repair 329). These investigators found lower rates of mortality (7.6% vs 15.2%; P = .0076), paraplegia (0% vs 5.6%; P<.0001), and stroke (0.85% vs 5.3%; P = .0028) in patients who underwent TEVAR rather than open repair.
      • Tang G.L.
      • Tehrani H.Y.
      • Usman A.
      • et al.
      Reduced mortality, paraplegia, and stroke with stent graft repair of blunt aortic transections: a modern meta-analysis.
      The SVS conducted a meta-analysis and systemic review that included 7768 patients from 139 studies with BTTAIs. Mortality was lower in TEVAR versus open and nonoperative treatments (9%, 19%, and 46%, respectively; P<.01). The risk for SCI was higher with open repair compared with TEVAR and nonoperative management (9%, 3%, and 3%, respectively; P = .01). The risk for end-stage renal disease (ESRD) was highest in open repair when compared with TEVAR and nonoperative treatment (8%, 5%, and 3%, respectively; P = .01). At a median 2-year follow-up, there was a trend toward increased risk of a secondary procedure in endovascular repair versus open repair (P = .07).
      • Lee A.W.
      • Matsumara J.S.
      • Mitchell R.S.
      • et al.
      Endovascular repair of traumatic thoracic aortic injury: clinical practice guidelines of the Society for Vascular Surgery.

      Summary

      Endovascular repair of BTTAI is the preferred treatment of choice in anatomically suitable patients (STS Class I recommendation, level of evidence B).
      • Svensson L.G.
      • Kouchoukos N.T.
      • Miller D.C.
      • et al.
      Expert consensus document on the treatment of descending thoracic aortic disease using endovascular stent-grafts.
      However, as the trauma population tends to be younger, there is a concern for graft migration as aortic remodeling occurs with age and growth. Therefore, adherence to a long-term follow-up protocol is imperative.

      Acute Aortic Syndrome

      Acute aortic syndrome (AAS) refers to a heterogeneous group of conditions that cause a common set of signs and symptoms, the commonest being aortic pain. AAS includes intramural hematoma (IMH), penetrating atherosclerotic aortic ulcer (PAU), and aortic dissection (AD) (Fig. 4).
      • Tsai T.T.
      • Nienaber C.A.
      • Eagle K.A.
      Contemporary reviews in cardiovascular medicine: acute aortic syndromes.
      Figure thumbnail gr4
      Fig. 4Aortic dissection (left), penetrating atherosclerotic ulcer (PAU) (middle), and intramural hematoma (IMH) (right), all causing acute aortic syndrome.
      (From Coady MA, Rizzo JA, Elefteriades JA. Pathologic variants of thoracic aortic dissections: penetrating atherosclerotic ulcers and intramural hematomas. Cardiol Clin 1999;17:640.)
      The Stanford system of classification for AD is applied to IMH and PAU. Stanford type A pathologies involve the ascending aorta and aortic arch, with or without descending aortic involvement. Stanford type B pathologies are confined to the descending aorta, distal to the origin of the LSCA.
      • Patel P.J.
      • Grande W.
      • Hieb R.A.
      Endovascular management of acute aortic syndromes.
      Regarding initial medical therapy for AAS, the goal is to stabilize the patient, control pain with opiates, lower heart rate (HR) and blood pressure (BP), and reduce the rate of increase or force (dP/dt) of left ventricular ejection.
      • Tsai T.T.
      • Nienaber C.A.
      • Eagle K.A.
      Contemporary reviews in cardiovascular medicine: acute aortic syndromes.
      First-line therapy is intravenous β-blockade. A HR of 60 beats/min or lower and a systolic blood pressure of 100 to 120 mm Hg, or the lowest appropriate level for adequate vital-organ perfusion, is recommended (ACC/AHA Class I recommendation, level of evidence C).
      • Hiratzka L.F.
      • Bakris G.L.
      • Beckman J.A.
      • et al.
      2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
      • Tsai T.T.
      • Nienaber C.A.
      • Eagle K.A.
      Contemporary reviews in cardiovascular medicine: acute aortic syndromes.
      • Patel P.J.
      • Grande W.
      • Hieb R.A.
      Endovascular management of acute aortic syndromes.
      In the presence of acute aortic regurgitation, β-blockers should be used with caution because they block compensatory tachycardia (ACC/AHA Class I recommendation, level of evidence C).
      • Hiratzka L.F.
      • Bakris G.L.
      • Beckman J.A.
      • et al.
      2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
      Labetalol, with both α- and β-blockade, lowers both BP and dP/dt.
      • Tsai T.T.
      • Nienaber C.A.
      • Eagle K.A.
      Contemporary reviews in cardiovascular medicine: acute aortic syndromes.
      • Patel P.J.
      • Grande W.
      • Hieb R.A.
      Endovascular management of acute aortic syndromes.
      In patients who are β-blocker intolerant, calcium-channel blockers can be used (ACC/AHA Class I recommendation, level of evidence C).
      • Hiratzka L.F.
      • Bakris G.L.
      • Beckman J.A.
      • et al.
      2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
      If β-blockers alone do not control BP, vasodilators are added (ACC/AHA Class I recommendation, level of evidence C).
      • Hiratzka L.F.
      • Bakris G.L.
      • Beckman J.A.
      • et al.
      2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
      Vasodilator therapy should not be initiated before HR control, to avoid the associated reflex tachycardia that might aggravate the AD (ACC/AHA Class III recommendation, level of evidence C).
      • Hiratzka L.F.
      • Bakris G.L.
      • Beckman J.A.
      • et al.
      2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.

      Aortic dissection

      The annual incidence of acute aortic dissection (AAD) is 5 to 30 cases per million people,
      • Coady M.A.
      • Ikonomidis J.S.
      • Cheung A.T.
      • et al.
      Surgical management of descending thoracic aortic disease: open and endovascular approaches: a scientific statement from the American Heart Association.
      accounting for 80% to 90% of all cases of AAS. The most common risk condition is hypertension (72%).
      • Tsai T.T.
      • Nienaber C.A.
      • Eagle K.A.
      Contemporary reviews in cardiovascular medicine: acute aortic syndromes.

      Type A aortic dissection

      The mortality rate of untreated acute type A dissection (TAAD) is 1% to 2% per hour after symptom onset.
      • Tsai T.T.
      • Nienaber C.A.
      • Eagle K.A.
      Contemporary reviews in cardiovascular medicine: acute aortic syndromes.
      Without surgery, mortality exceeds 50% at 1 month.
      • Tsai T.T.
      • Nienaber C.A.
      • Eagle K.A.
      Contemporary reviews in cardiovascular medicine: acute aortic syndromes.
      At present, urgent surgical repair is the treatment of choice for TAADs (ACC/AHA Class I recommendation, level of evidence B).
      • Hiratzka L.F.
      • Bakris G.L.
      • Beckman J.A.
      • et al.
      2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
      Patients with TAADs in the International Registry of Aortic Dissection (IRAD) database had an overall in-hospital mortality of 27% for patients treated surgically and 56% for those treated medically.
      • Patel P.J.
      • Grande W.
      • Hieb R.A.
      Endovascular management of acute aortic syndromes.
      Recently, endovascular techniques have been added as adjuncts to the surgical management of TAADs. For dissections extending into the descending thoracic aorta, placement of a stent graft into the unrepaired descending aorta can reduce the complications related to the residual dissected vessel. Some surgeons advocate endovascular treatment of TAADs that extend in a retrograde fashion from a dissection originating in the descending thoracic aorta by covering the tear on the primary entry site. Others propose endovascular treatment of malperfusion states in patients with TAADs before operative repair of the ascending aorta.
      • Patel P.J.
      • Grande W.
      • Hieb R.A.
      Endovascular management of acute aortic syndromes.
      Ye and colleagues
      • Ye C.
      • Chang G.
      • Li S.
      • et al.
      Endovascular stent-graft treatment for Stanford type A aortic dissection.
      reported on a series of 45 patients with Stanford type A dissection, treated with TEVAR. The entry tear was located at the ascending aorta in 10 cases, the aortic arch in 14 cases, and the distal aortic arch or proximal descending aorta in 21 cases where the ascending aorta was also involved by the dissection. The surgical success rate of the cohort was 98%, with a mortality rate of 6.7%. Type I endoleaks occurred in 10 cases.
      • Ye C.
      • Chang G.
      • Li S.
      • et al.
      Endovascular stent-graft treatment for Stanford type A aortic dissection.

      Uncomplicated type B aortic dissection

      Uncomplicated type B aortic dissections (TBADs) are best treated with medical therapy (ACC/AHA Class I recommendation, level of evidence C).
      • Hiratzka L.F.
      • Bakris G.L.
      • Beckman J.A.
      • et al.
      2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
      Patients with TBADs in the IRAD database had an overall in-hospital mortality of 29.3% for patients treated surgically and 10% for those treated medically.
      • Patel P.J.
      • Grande W.
      • Hieb R.A.
      Endovascular management of acute aortic syndromes.
      Medical therapy alone does not stop blood flow to the false lumen and, consequently, 20% to 50% of patients who survive the acute phase develop dilatation of the false lumen at 4 years, requiring intervention.
      • Hiratzka L.F.
      • Bakris G.L.
      • Beckman J.A.
      • et al.
      2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
      • Coady M.A.
      • Ikonomidis J.S.
      • Cheung A.T.
      • et al.
      Surgical management of descending thoracic aortic disease: open and endovascular approaches: a scientific statement from the American Heart Association.
      As a result, medical therapy alone is associated with a mortality rate of 50% at 5 years.
      • Coady M.A.
      • Ikonomidis J.S.
      • Cheung A.T.
      • et al.
      Surgical management of descending thoracic aortic disease: open and endovascular approaches: a scientific statement from the American Heart Association.
      The INSTEAD (Investigation of Stent Grafts in Aortic Dissection) trial
      • Nienaber C.A.
      • Rousseau H.
      • Eggebrecht H.
      • et al.
      INSTEAD Trial randomized comparison of strategies for type B aortic dissection: the INvestigation of STEnt Grafts in Aortic Dissection (INSTEAD) trial.
      was designed to answer the question of whether TEVAR in patients with chronic uncomplicated TBADs could reduce late aortic related morbidity and mortality. The investigators examined 140 patients with stable, uncomplicated chronic TBADs, all of whom were randomized to optimal medical therapy versus optimal medical therapy plus TEVAR of the proximal aortic tear. Patients treated with optimal medical therapy had overall and aortic-related death rates of 4.4% and 2.9%, respectively, whereas the rates in the TEVAR group were 11.1% and 5.6%. At 2 years there was no significant difference in all-cause mortality. Significant aortic remodeling was noted in the TEVAR group, with 91% complete thrombosis at 2 years compared with 19% in the optimal medical therapy group (P<.001).
      • Patel P.J.
      • Grande W.
      • Hieb R.A.
      Endovascular management of acute aortic syndromes.
      • Nienaber C.A.
      • Rousseau H.
      • Eggebrecht H.
      • et al.
      INSTEAD Trial randomized comparison of strategies for type B aortic dissection: the INvestigation of STEnt Grafts in Aortic Dissection (INSTEAD) trial.
      This result is significant, as false-lumen thrombosis and true-lumen expansion may prevent late aneurysm formation.
      • Patel P.J.
      • Grande W.
      • Hieb R.A.
      Endovascular management of acute aortic syndromes.
      Although TEVAR failed to improve late outcomes compared with medical therapy in uncomplicated chronic TBADs, results may differ in acute uncomplicated TBADs. Stent grafting might be more effective in the acute setting before septal fibrosis of the dissecting membrane occurs, which can limit aortic remodeling.
      • Patel P.J.
      • Grande W.
      • Hieb R.A.
      Endovascular management of acute aortic syndromes.
      More definitive data on the role of TEVAR for acute uncomplicated TBADs will be forthcoming as results from the ADSORB (European Study of Medical Management vs TAG Device and Medical Management for Acute Uncomplicated Type B Dissection) trial become available.
      • Patel P.J.
      • Grande W.
      • Hieb R.A.
      Endovascular management of acute aortic syndromes.

      Gore & Associates. A European study of medical management versus TAG device and medical management for acute uncomplicated type B dissection (ADSORB). Available at: ClinicalTrials.gov. Accessed March 22, 2010.

      Summary

      Medical therapy remains the gold standard in uncomplicated TBADs. However, a recent study showed that patients with uncomplicated TBADs with false-lumen diameters of greater than 22 mm had a significantly higher risk for aneurysmal formation; this may represent a subset of patients with uncomplicated TBADs for whom early endovascular management may be appropriate.
      • Patel P.J.
      • Grande W.
      • Hieb R.A.
      Endovascular management of acute aortic syndromes.

      Complicated type B aortic dissection

      Approximately 30% of acute TBADs are complicated at initial presentation, and 1 in 5 of uncomplicated TBADs will become complicated, requiring open surgical repair (ACC/AHA Class I recommendation, level of evidence B)
      • Hiratzka L.F.
      • Bakris G.L.
      • Beckman J.A.
      • et al.
      2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
      or endovascular repair.
      • Fattori R.
      • Tsai T.
      • Myrmel T.
      • et al.
      Complicated acute type B dissection: is surgery still the best option? A report for the International Registry of Acute Aortic Dissection (IRAD).
      The goal of intervention is to obliterate the entry tear and achieve end-organ perfusion. Patients presenting with rupture or impending rupture, end-organ malperfusion, limb ischemia, unrelenting pain, and uncontrollable hypertension are designated as having a complicated TBAD.
      • Tsai T.T.
      • Nienaber C.A.
      • Eagle K.A.
      Contemporary reviews in cardiovascular medicine: acute aortic syndromes.
      • Patel P.J.
      • Grande W.
      • Hieb R.A.
      Endovascular management of acute aortic syndromes.
      The recent IRAD database demonstrated that surgical repair for acute TBAD is associated with a significant risk of cerebrovascular accident (9.0%), paraplegia (4.5%), visceral ischemia/infarction (6.8%), and acute renal failure (18.3%), all of which correlated with postoperative death.
      • Trimarchi S.
      • Nienaber C.A.
      • Rampoldi V.
      • et al.
      Role and results of surgery in acute type B aortic dissection: insights from the International Registry of Acute Aortic Dissection (IRAD).
      The overall in-hospital mortality was 29.3%, and for patients whose procedures were within 48 hours the in-hospital mortality was 39.2%.
      • Trimarchi S.
      • Nienaber C.A.
      • Rampoldi V.
      • et al.
      Role and results of surgery in acute type B aortic dissection: insights from the International Registry of Acute Aortic Dissection (IRAD).
      For patients presenting with malperfusion and rupture, the in-hospital mortality was 27.8% and 62.5%, respectively.
      • Trimarchi S.
      • Nienaber C.A.
      • Rampoldi V.
      • et al.
      Role and results of surgery in acute type B aortic dissection: insights from the International Registry of Acute Aortic Dissection (IRAD).
      The following endovascular techniques are used to repair complicated TBADs:

      Aortic fenestration

      The goal of endovascular aortic fenestration is to treat malperfusion syndromes by equalization of pressures between the true and false lumens, relieving the dynamic aortic component of obstruction caused by the dissection. Branch-vessel stenting is then used to treat the static obstruction of branch vessels caused by the dissection. However, by preserving flow through the false lumen, aortic fenestration does not address complications such as aneurysm formation and late rupture. Analysis of complicated TBADs from the IRAD database reveals that malperfusion states were relieved in 9 of 18 patients treated with endovascular fenestration and in 16 of 17 patients treated with stent grafts.
      • Patel P.J.
      • Grande W.
      • Hieb R.A.
      Endovascular management of acute aortic syndromes.
      Therefore, endograft therapy should be used if a suitable entry tear is present, and fenestration should be reserved for cases whereby malperfusion is present and there is no entry tear amenable to endograft treatment.
      • Patel P.J.
      • Grande W.
      • Hieb R.A.
      Endovascular management of acute aortic syndromes.

      Endovascular repair (STS Class I recommendation, level of evidence A)

      The rationale behind endovascular therapy (Fig. 5)
      • Adams J.D.
      • Garcia L.M.
      • Kern J.A.
      Endovascular repair of the thoracic aorta.
      is that covering the area of the primary intimal tear with a stent graft promotes false-lumen thrombosis and subsequent aortic remodeling by eliminating antegrade (or occasionally retrograde) flow into the false lumen.
      • Svensson L.G.
      • Kouchoukos N.T.
      • Miller D.C.
      • et al.
      Expert consensus document on the treatment of descending thoracic aortic disease using endovascular stent-grafts.
      In general, stent grafts deployed for the treatment of ADs should extend 20 to 40 mm beyond the primary intimal tear site in both the proximal and distal directions.
      • Patel P.J.
      • Grande W.
      • Hieb R.A.
      Endovascular management of acute aortic syndromes.
      Figure thumbnail gr5
      Fig. 5(A) Multiplanar reconstruction of a patient with acute type B aortic dissection. (B) Multiplanar reconstruction of the same patient 6 months after successful endovascular repair.
      (From Adams JD, Garcia LM, Kern JA. Endovascular repair of the thoracic aorta. Surg Clin North Am 2009;89:895–912.)
      In a systematic review, Parker and Golledge
      • Parker J.D.
      • Golledge J.
      Outcome of endovascular treatment of acute type B aortic dissection.
      reported the findings of multiple centers, over 10 years, of 942 patients who underwent TEVAR for acute TBAD with complications. Procedural success was achieved in 95% of all cases, with emergency conversion being required in 0.6% of patients. Overall in-hospital mortality was 9.1%, with an early complication rate of 8.1% (stroke 3.1%; paraplegia 1.9%; conversion to type A dissection 2%; bowel infarction 0.9%; and major amputation 0.2%). After an average follow-up of 20 months, reintervention was required in 10.4% of patients, with aortic rupture in 0.8% of the cases. Average overall survival was 88% at 20 months.
      • Cao C.Q.
      • Bannon P.G.
      • Shee R.
      • et al.
      Thoracic endovascular aortic repair-indications and evidence.
      • Parker J.D.
      • Golledge J.
      Outcome of endovascular treatment of acute type B aortic dissection.
      Results from IRAD comparing stent grafting with open surgery for treating complicated acute TBADs showed a decrease in in-hospital mortality (33.9% vs 10.6%) and neurologic/ischemic composite morbidity (20.8% vs 40.0%).
      • Patel P.J.
      • Grande W.
      • Hieb R.A.
      Endovascular management of acute aortic syndromes.
      • Fattori R.
      • Tsai T.
      • Myrmel T.
      • et al.
      Complicated acute type B dissection: is surgery still the best option? A report for the International Registry of Acute Aortic Dissection (IRAD).
      A recent review of the Nationwide Inpatient Sample identified 5000 patients who underwent repair of TBADs (3619 open vs 1381 TEVAR) and found that the TEVAR group had a lower 30-day mortality (10.6% vs 19% for open repair).
      • Sachs T.
      • Pomposelli F.
      • Hagberg R.
      • et al.
      Open and endovascular repair of type B aortic dissection in the Nationwide Inpatient Sample.
      However, a recent IRAD review demonstrated no difference in 3-year survival in patients with acute TBADs managed medically (77.6%), surgically (82.8%), or with endovascular therapy (76.2%).
      • Tsai T.T.
      • Fattori R.
      • Trimarchi S.
      • et al.
      Long-term survival inpatients presenting with type B acute aortic dissection: insights from the International Registry of Acute Aortic Dissection.
      These data emphasize the importance of follow-up regardless of the mode of therapy.

      Summary

      Endovascular repair of acute complicated TBAD is associated with low morbidity and mortality, and has emerged as the treatment modality of choice.

      Intramural hematoma

      IMH, a precursor of AD, is caused by primary rupture of the vasa vasorum in the aortic medial wall, leading to a concentric hematoma within the media. It has no intimal flap or false lumen. IMH is associated with hypertension, and 70.6% of cases are located in the descending thoracic aorta.
      • Coady M.A.
      • Ikonomidis J.S.
      • Cheung A.T.
      • et al.
      Surgical management of descending thoracic aortic disease: open and endovascular approaches: a scientific statement from the American Heart Association.
      On diagnostic imaging IMH appears as a smooth, crescentic, or circular thickening greater than 5 to 7 mm in size. Acute IMH accounts for 5% to 20% of all cases of AAS, with regression in 10%, progression to classic AD in 28% to 47%, and a risk of rupture in 20% to 45%. Long-term surveillance is therefore necessary.
      • Tsai T.T.
      • Nienaber C.A.
      • Eagle K.A.
      Contemporary reviews in cardiovascular medicine: acute aortic syndromes.
      • Patel P.J.
      • Grande W.
      • Hieb R.A.
      Endovascular management of acute aortic syndromes.
      A meta-analysis of 143 patients found that patients with lesions of the ascending aorta had a lower mortality with surgery than with medical treatment (14% vs 36%). Patients with lesions of the descending aorta had a similar mortality with medical or surgical therapy (14% vs 20%).
      • Tsai T.T.
      • Nienaber C.A.
      • Eagle K.A.
      Contemporary reviews in cardiovascular medicine: acute aortic syndromes.
      As a result, IMH is treated similarly to AD in the corresponding segment of the aorta (ACC/AHA Class IIa recommendation, level of evidence C).
      • Hiratzka L.F.
      • Bakris G.L.
      • Beckman J.A.
      • et al.
      2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
      The following is recommended
      • Tsai T.T.
      • Nienaber C.A.
      • Eagle K.A.
      Contemporary reviews in cardiovascular medicine: acute aortic syndromes.
      • Patel P.J.
      • Grande W.
      • Hieb R.A.
      Endovascular management of acute aortic syndromes.
      :
      • For patients with type A IMH, open surgery is recommended.
      • For patients with uncomplicated type B IMH, best medical treatment and close surveillance is recommended.
      • For patients with complicated type B IMH (aneurysmal degeneration of the aorta, aortic diameter greater than 50 mm, persistent pain or hypertension, organ/limb ischemia, hematoma thickness greater than 11 mm, or pleural/pericardial fluid), best medical therapy and TEVAR is recommended (STS Class IIa recommendation, level of evidence C).
        • Svensson L.G.
        • Kouchoukos N.T.
        • Miller D.C.
        • et al.
        Expert consensus document on the treatment of descending thoracic aortic disease using endovascular stent-grafts.

      Penetrating atherosclerotic aortic ulcer

      PAUs are present in 2.3% to 11% of patients with AAS, and two-thirds of cases occur in the descending thoracic aorta. PAU is a condition whereby an atherosclerotic aortic plaque penetrates the internal elastic lamina into the aortic media. It is associated with a type B IMH in 80% of cases. Patients with PAUs are typically older and hypertensive with multiple medical comorbidities. PAU may lead to pseudoaneurysm formation, AD, and aortic rupture.
      • Tsai T.T.
      • Nienaber C.A.
      • Eagle K.A.
      Contemporary reviews in cardiovascular medicine: acute aortic syndromes.
      • Patel P.J.
      • Grande W.
      • Hieb R.A.
      Endovascular management of acute aortic syndromes.
      At present, there is no generally accepted therapeutic regimen for PAUs. In general, patients with type A PAUs are treated with surgical resection. Stable patients with type B PAUs may be managed medically, with strict follow-up and serial imaging. Criteria for endograft placement in the acute setting include pain and rupture; in chronic cases, indications include recurrent pain, aortic diameter greater than 55 mm, and increase in size greater than 10 mm per year
      • Patel P.J.
      • Grande W.
      • Hieb R.A.
      Endovascular management of acute aortic syndromes.
      • Botta L.
      • Buttazzi K.
      • Russo V.
      • et al.
      Endovascular repair for penetrating atherosclerotic ulcers of the descending thoracic aorta: early and mid-term results.
      (STS Class IIa recommendation, level of evidence C).
      • Svensson L.G.
      • Kouchoukos N.T.
      • Miller D.C.
      • et al.
      Expert consensus document on the treatment of descending thoracic aortic disease using endovascular stent-grafts.
      Most PAUs are isolated and localized in a relatively normal-sized aorta, which makes them ideal targets for endovascular exclusion. However, patients with PAUs have severe, diffuse atherosclerotic disease, which puts them at an increased risk of atheroembolic complications. Therefore, minimal manipulation of the guide wire and delivery system in the thoracic aorta is imperative.
      • Tsai T.T.
      • Nienaber C.A.
      • Eagle K.A.
      Contemporary reviews in cardiovascular medicine: acute aortic syndromes.
      In 2009, Eggebrecht and colleagues
      • Eggebrecht H.
      • Plicht B.
      • Kahlert P.
      • et al.
      Intramural hematoma and penetrating ulcers: indications to endovascular treatment.
      summarized data regarding the success of endografting in the treatment of PAU, reporting high overall technical success rates (98%) and low rates of in-hospital mortality (7%), neurologic complications (4%), and secondary (5%) and subsequent (2%) aorta-related mortality.

      Thoracoabdominal Aortic Aneurysms

      Approximately 10% of TAAs occur in the thoracoabdominal aorta. The 5-year survival rate of patients with TAAAs treated nonsurgically is 19% and for those treated surgically, 73.5%.
      • Coselli J.S.
      • Conklin L.D.
      • LeMaire S.A.
      Thoracoabdominal aortic aneurysm repair: review and update of current strategies.
      Therefore, an interventional treatment option is mandatory for these patients.

      Open surgical repair

      Coselli and colleagues
      • Coselli J.S.
      • Bozinovski J.
      • LeMaire S.A.
      Open surgical repair of 2286 thoracoabdominal aortic aneurysms.
      reported their experience with OSR of 2286 TAAAs. The 30-day survival rate was 95.0%. Renal failure requiring hemodialysis occurred in 129 patients (5.6%), paraplegia or paraparesis developed in 87 patients (3.8%), pulmonary complications occurred in 734 patients (32.1%), and cardiac events occurred in 181 patients (7.9%). Bleeding requiring a return to the operating room occurred after 57 TAAA repairs (2.5%). Patients who underwent replacement of the entire thoracoabdominal aorta (extent II) had the highest rates of death (6.0%), spinal cord deficit (6.3%), and renal failure (8.3%). Current management strategies enable patients to undergo conventional open TAAA repair with excellent early survival and acceptable morbidity.
      • Coselli J.S.
      • Bozinovski J.
      • LeMaire S.A.
      Open surgical repair of 2286 thoracoabdominal aortic aneurysms.

      Hybrid procedure

      Moulakakis and colleagues
      • Moulakakis K.G.
      • Mylonas S.N.
      • Avgerinos E.D.
      • et al.
      Hybrid open endovascular technique for aortic thoracoabdominal pathologies.
      performed a meta-analysis to assess the safety and efficacy of a hybrid technique in 507 patients with TAAAs or other aortic abnormalities. The pooled estimates for primary technical success and visceral graft patency were 96.2% and 96.5%, respectively. A pooled rate of 7.5% for overall SCI symptoms was observed, whereas for irreversible paraplegia the pooled rate was 4.5%. The pooled estimate for renal failure was 8.8%. The pooled 30-day in-hospital mortality rate was 12.8%. During the mean follow-up period of 34.5 months, a total of 119 endoleaks were identified in 111 patients (22.7%).
      • Moulakakis K.G.
      • Mylonas S.N.
      • Avgerinos E.D.
      • et al.
      Hybrid open endovascular technique for aortic thoracoabdominal pathologies.
      The complications typical of TAAA open surgery have not been eliminated by TAAA hybrid repair. Morbidity and mortality rates remain substantial, and TAAA hybrid repair should only be considered in patients who are unsuited for conventional OSR.

      Endovascular repair of TAAA

      Endovascular repair of TAAA (STS Class IIb recommendation, level of evidence C) is considered when the patient has significant comorbidity.
      • Svensson L.G.
      • Kouchoukos N.T.
      • Miller D.C.
      • et al.
      Expert consensus document on the treatment of descending thoracic aortic disease using endovascular stent-grafts.
      A retrospective review by Bakoyiannis and colleagues
      • Bakoyiannis C.N.
      • Economopoulos K.P.
      • Georgopoulos S.
      • et al.
      Fenestrated and branched endografts for the treatment of thoracoabdominal aortic aneurysms: a systematic review.
      reported on outcomes of 155 patients who underwent fenestrated and branched endograft insertion for TAAAs. Technical success was achieved in 94.2% of patients. Twenty-three (18.4%) primary endoleaks were reported. All 26 secondary interventions were elective, most occurring within the first month. The 30-day mortality was 7.1% while the 1-year survival rate was 82.6%. Three (1.9%) patients developed permanent paraplegia and 2 (1.3%) developed permanent paraparesis; renal failure was reported in 9 (5.8%). Overall follow-up mortality was 16.1%.
      • Bakoyiannis C.N.
      • Economopoulos K.P.
      • Georgopoulos S.
      • et al.
      Fenestrated and branched endografts for the treatment of thoracoabdominal aortic aneurysms: a systematic review.
      Fig. 6
      • Greenberg R.
      • Eagleton M.
      • Mastracci T.
      Branched endografts for thoracoabdominal aneurysms.
      illustrates a reinforced fenestration, and the implantation of a stent graft with branches to the visceral arteries is shown in Fig. 7.
      • Greenberg R.K.
      • Lu Q.
      • Roselli E.E.
      • et al.
      Contemporary analysis of descending thoracic and thoracoabdominal aneurysm repair: a comparison of endovascular and open techniques.
      Figure thumbnail gr6
      Fig. 6A fenestration placed in the distal end of a thoracic device. There upper left photo shows a balloon-expandable stent placed through the fenestration, inflated to a diameter matching the target vessel (upper right). A larger balloon is then placed into the aortic portion of the stent and used to flare the stent against the aortic graft wall (lower panels).
      (From Greenberg R, Eagleton M, Mastracci T. Branched endografts for thoracoabdominal aneurysms. J Thorac Cardiovasc Surg 2010;140(Suppl 6):S171–8; with permission.)
      Figure thumbnail gr7
      Fig. 7(A, B) Anterior and lateral views of a 3-dimensional reconstruction of a type II thoracoabdominal aortic aneurysm treated with a branched endovascular graft. The celiac and superior mesenteric branches (white arrows) are attached to the aortic graft as a side arm and oriented in the direction of the mesenteric vessel. The patient had 2 right renal arteries. The lowest was embolized with coils (yellow arrow). The upper right and left renal arteries were incorporated into the repair with reinforced fenestrations (green arrows) mated with stent grafts.
      (From Greenberg RK, Lu Q, Roselli EE, et al. Contemporary analysis of descending thoracic and thoracoabdominal aneurysm repair: a comparison of endovascular and open techniques. Circulation 2008;118:808–17; with permission.)
      Endovascular repair of TAAAs is technically feasible and shows great promise in patients considered at high risk for open surgery. However, mortality and SCI is still considerable with this technique.

      Aortic Arch Aneurysms

      OSR of aortic arch aneurysms is associated with a 5% to 7% risk of death and a 2% to 5% risk of stroke.
      • Patel H.J.
      • Deeb G.M.
      Ascending and arch aorta: pathology, natural history, and treatment.
      Recently, hybrid procedures have been used to treat complex aortic arch aneurysms in high-risk patients who are not suitable for open surgical repair. In patients with aortic arch aneurysms with severe comorbidities, recent guidelines support an endovascular repair technique (STS Class IIb recommendation, level of evidence C),
      • Svensson L.G.
      • Kouchoukos N.T.
      • Miller D.C.
      • et al.
      Expert consensus document on the treatment of descending thoracic aortic disease using endovascular stent-grafts.
      and for patients who have reasonable surgical risk, the recent guidelines advise against an endovascular repair technique (STS Class III recommendation; level of evidence A).
      • Svensson L.G.
      • Kouchoukos N.T.
      • Miller D.C.
      • et al.
      Expert consensus document on the treatment of descending thoracic aortic disease using endovascular stent-grafts.
      A systematic review of arch hybrid outcomes in 195 patients showed pooled perioperative mortality and morbidity rates of 9% and 21%, respectively. The most common perioperative complication was stroke (7%). The overall technical success rate was 86%, and the most common reason for technical failure was endoleak (9%). Four aneurysm-related deaths were reported during follow-up (2%).
      • Antoniou G.A.
      • El Sakka K.
      • Hamady M.
      • et al.
      Hybrid treatment of complex aortic arch disease with supra-aortic debranching and endovascular stent graft repair.

      Summary

      Aortic arch hybrid repair is a feasible alternative treatment in patients who are unfit for OSR. Patients with extensive atheromatous involvement of the aortic arch have a high risk of atheroembolization caused by wire and device manipulation, and are not suitable for this technique. Long-term follow-up is necessary to evaluate the efficacy and safety of these new devices.
      • Antoniou G.A.
      • El Sakka K.
      • Hamady M.
      • et al.
      Hybrid treatment of complex aortic arch disease with supra-aortic debranching and endovascular stent graft repair.

      Summary of Indications and Outcomes for TEVAR in Thoracic Aortic Disease

      The most recent large meta-analysis, by Cheng and colleagues,
      • Cheng D.
      • Martin J.
      • Shennib H.
      • et al.
      Endovascular aortic repair versus open surgical repair for descending thoracic aortic disease a systematic review and meta-analysis of comparative studies.
      examined TEVAR versus open repair for descending thoracic aortic disease. This analysis included 5888 patients from 42 articles, 38 of which were comparative studies and 4 from registry data. Pooled data indicated that overall, TEVAR patients were older and had more comorbidities than the open surgical patients. There was a significant reduction for TEVAR in comparison with open repair for all-cause mortality at 30 days, paraplegia or paraparesis, transfusions, reoperation for bleeding, renal dysfunction, pneumonia, and cardiac, neurologic, respiratory, and overall complications. There was a decrease in length of hospital stay (−7 days), length of stay in the intensive care unit (−4 days), and procedure time (−142 min) for TEVAR versus open repair. This meta-analysis is consistent with current literature and serves to further validate the aforementioned data. The findings of this study and the indications for TEVAR are summarized in Tables 1 and 2.
      Table 1Outcomes of TEVAR versus open surgical repair for descending thoracic aortic disease
      Data from Cheng D, Martin J, Shennib H, et al. Endovascular aortic repair versus open surgical repair for descending thoracic aortic disease a systematic review and meta-analysis of comparative studies. J Am Coll Cardiol 2010;55:986–1001.
      TEVAR (%)Open Surgery (%)I2, %OR (95% CI)P Value
      Death, 30-d5.813.900.44 (0.33–0.59)<.00001
      Death, 1-y16.021.900.73 (0.53–1.02).07
      Death, 2- to 3-y23.024.800.92 (0.63–1.33).65
      Permanent paraplegia1.44.900.30 (0.14–0.62).001
      Stroke5.06.2230.75 (0.50–1.13).17
      Acute myocardial infarction2.36.3200.81 (0.43–1.53).51
      Renal dysfunction5.915.700.40 (0.25–0.63)<.001
      Reoperation for bleeding0.016.500.26 (0.11–0.62).002
      Transfused patients3.983.7230.01(0.002–0.04)<.0001
      Reintervention8.19.10%1.01 (0.64–1.60).95
      Pneumonia15.928.7440.14 (0.23–0.71).002
      Vascular complications13.021.9830.58 (0.19–1.76).34
      Overall complications41.469.3630.19 (0.10–0.36)<.0001
      I2 = percent heterogeneity across trials that cannot be explained by chance variation alone. I2 >50% indicates high heterogeneity.
      Abbreviations: CI, confidence interval; OR, odds ratio.
      Table 2Society of Thoracic Surgeons summary of recommendation classifications and level of evidence for TEVAR
      Data from Svensson LG, Kouchoukos NT, Miller DC, et al. Expert consensus document on the treatment of descending thoracic aortic disease using endovascular stent-grafts. Ann Thorac Surg 2008;85(Suppl 1):S1–41.
      Entity/SubgroupClassificationLevel of Evidence
      Penetrating Ulcer/Intramural Hematoma
       AsymptomaticIIIC
       SymptomaticIIaC
       Chronic traumaticllaC
      Acute Traumatic Aortic TransectionlB
      Acute Type B Dissection
       IschemiaIA
       No ischemiaIIbC
      Subacute DissectionIIbB
      Chronic DissectionIIbB
      Degenerative descending
       >5.5 cm, comorbidityIIaB
       >5.5 cm, no comorbidityIIbC
       <5.5 cmIIIC
      Arch
       Reasonable open riskIIIA
       Severe comorbidityIIbC
      Thoracoabdominal/Severe comorbidityIIbC

      Contraindications for TEVAR

      TEVAR is not recommended in patients with connective tissue disease except as a bail-out procedure or bridge to definitive open surgical therapy, or as a procedure following prior aortic repair when both landing zones lie within previously sited prosthetic grafts.
      • Grabenwoger M.
      • Alfonso F.
      • Bachet J.
      • et al.
      Thoracic endovascular aortic repair (TEVAR) for the treatment of aortic diseases: a position statement from the European Association for Cardio-Thoracic Surgery (EACTS) and the European Society of Cardiology (ESC), in collaboration with the European Association of Percutaneous Cardiovascular Interventions (EAPCI).

      Anesthetic management

      Preanesthetic Evaluation and Preparation

      Patients presenting for TEVAR are typically elderly with significant medical comorbidities that can influence operative risk. Published data indicate a high incidence of hypertension (59.1%), coronary artery disease (27.0%), pulmonary disease (20.9%), renal disease (13.6%), and congestive heart failure (11.2%).
      • Findeiss L.K.
      • Cody M.E.
      Endovascular repair of the thoracic aortic aneurysms.
      • Davies R.R.
      • Goldstein L.J.
      • Coady M.A.
      • et al.
      Yearly rupture or dissection rates for thoracic aortic aneurysms: simple prediction based on size.
      Preoperative evaluation of these comorbidities will identify patients at high risk for complications and allow alterations in perioperative management. Although TEVAR is associated with fewer fluid shifts, absence of aortic cross-clamping, and a smaller surgical incision, it is still considered high-risk surgery, based on a perioperative risk of major adverse cardiac events of greater than 5%. At present there is no TEVAR-specific risk stratification tool available. Patients should undergo functional testing, when indicated, based on the ACC/AHA guidelines, for preoperative evaluation of patients undergoing noncardiac surgery.

      Argalious M. Endovascular aortic repair in the descending thoracoabdominal aorta [abstract 322]. In: Programs and abstracts of the American Society of Anesthesiologists’ Annual Meeting. Chicago, IL, October 15–17, 2011. p. 1–9.

      • Grabenwoger M.
      • Alfonso F.
      • Bachet J.
      • et al.
      Thoracic endovascular aortic repair (TEVAR) for the treatment of aortic diseases: a position statement from the European Association for Cardio-Thoracic Surgery (EACTS) and the European Society of Cardiology (ESC), in collaboration with the European Association of Percutaneous Cardiovascular Interventions (EAPCI).
      • Fleisher L.A.
      • Beckman J.A.
      • Brown K.A.
      • et al.
      ACC/AHA 2007 guidelines on perioperative cardiovascular evaluation and care for noncardiac surgery: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 2002 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery) developed in collaboration with the American Society of Echocardiography, American Society of Nuclear Cardiology, Heart Rhythm Society, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society for Vascular Medicine and Biology, and Society for Vascular Surgery.

      Specific Anesthetic Considerations Related to TEVAR

      Potential for open conversion

      Operative procedures involving endovascular repair of the thoracic aorta have the potential for catastrophic bleeding and cardiovascular collapse.
      • Gutsche J.T.
      • Szeto W.
      • Cheung A.T.
      Endovascular stenting of thoracic aortic aneurysm.
      • Miller R.
      Anesthesia for vascular surgery.

      Peripheral vascular disease

      Patients who have peripheral vascular disease are at risk for access-site complications such as vascular injury and bleeding. The caliber, degree of atherosclerotic disease, and tortuosity should be preoperatively assessed using CTA or MRA. After TEVAR they should also be assessed for vascular insufficiency.
      • Adams J.D.
      • Garcia L.M.
      • Kern J.A.
      Endovascular repair of the thoracic aorta.
      • Gutsche J.T.
      • Szeto W.
      • Cheung A.T.
      Endovascular stenting of thoracic aortic aneurysm.
      • Miller R.
      Anesthesia for vascular surgery.

      Adjunctive procedures

      Debranching procedures and retroperitoneal dissections to create surgical conduits (iliac artery or aortic) for vascular access are associated with greater blood loss, longer procedure times, and a longer length of stay in hospital than TEVAR with standard femoral access.
      • Miller R.
      Anesthesia for vascular surgery.

      Acute kidney injury following TEVAR

      Acute kidney injury (AKI) following TEVAR is multifactorial and can occur as a result of (1) hypoperfusion, (2) mechanical encroachment of the stent graft on the renal vessels, (3) emboli to the renal arteries, and (4) radiographic contrast-induced nephropathy (CIN). Preexisting renal insufficiency is the most important and predictive risk factor for developing CIN.

      Argalious M. Endovascular aortic repair in the descending thoracoabdominal aorta [abstract 322]. In: Programs and abstracts of the American Society of Anesthesiologists’ Annual Meeting. Chicago, IL, October 15–17, 2011. p. 1–9.

      • Goldfarb S.
      • McCullough P.A.
      • McDermott J.
      • et al.
      Contrast-induced acute kidney injury: specialty-specific protocols for interventional radiology, diagnostic computed tomography radiology, and interventional cardiology.

      Strategies to reduce the incidence of AKI following TEVAR

      • Maintain a normal cardiac index, a normal mean arterial blood pressure (MAP), and normovolemia.

        Argalious M. Endovascular aortic repair in the descending thoracoabdominal aorta [abstract 322]. In: Programs and abstracts of the American Society of Anesthesiologists’ Annual Meeting. Chicago, IL, October 15–17, 2011. p. 1–9.

        • Goldfarb S.
        • McCullough P.A.
        • McDermott J.
        • et al.
        Contrast-induced acute kidney injury: specialty-specific protocols for interventional radiology, diagnostic computed tomography radiology, and interventional cardiology.
      • Use iso-osmolar, nonionic contrast dye and limit contrast dye exposure: a ratio of contrast medium volume to CrCl (creatinine clearance) of greater than 3.7 is associated with increased risk of CIN.
      • Substitute intravascular ultrasonography for angiography or use CO2 angiography.
      • Avoid nephrotoxins; stop metformin 48 hours before contrast dye administration, as it can cause lactic acidosis.
      • Intravenous bicarbonate: Administer a 3 mL/kg bolus of isotonic bicarbonate, a minimum of 1 hour before the procedure, and continue at a rate of 1 mL/kg per hour for 6 hours after the procedure.
      • Acetylcysteine: Administer 1200 mg orally twice daily on the day before, the day of, and the day after the procedure.

      Stroke

      The incidence of stroke after TEVAR is between 2% and 8%.
      • Feezor R.J.
      • Martin T.D.
      • Hess P.J.
      • et al.
      Risk factors for perioperative stroke during thoracic endovascular aortic repairs (TEVAR).
      • Ullery B.W.
      • McGarvey M.
      • Cheung A.T.
      • et al.
      Vascular distribution of stroke and its relationship to perioperative mortality and neurologic outcome after thoracic endovascular repair.
      Patients who have had a prior transient ischemic attack (TIA) or stroke are at a higher risk for perioperative stroke, and should have a computed tomography (CT) or transesophageal echocardiography (TEE) evaluation to grade the severity and mobility of the aortic atheroma.
      • Gutsche J.T.
      • Szeto W.
      • Cheung A.T.
      Endovascular stenting of thoracic aortic aneurysm.
      Strokes are related to the severity, mobility, and instrumentation of the vulnerable atherosclerotic plaque within the aorta.
      • Adams J.D.
      • Garcia L.M.
      • Kern J.A.
      Endovascular repair of the thoracic aorta.
      In a retrospective study of 530 patients, Ullery and colleagues
      • Ullery B.W.
      • McGarvey M.
      • Cheung A.T.
      • et al.
      Vascular distribution of stroke and its relationship to perioperative mortality and neurologic outcome after thoracic endovascular repair.
      assessed the vascular distribution of stroke after TEVAR and its relationship to perioperative death and neurologic outcome. Stroke complicated 3.8% of the TEVAR procedures, with 60% involving the posterior circulation and 40% the anterior circulation. Patients who sustained a perioperative stroke had increased in-hospital mortality when compared with those patients whom did not suffer a stroke (20% vs 5.7%).
      • Ullery B.W.
      • McGarvey M.
      • Cheung A.T.
      • et al.
      Vascular distribution of stroke and its relationship to perioperative mortality and neurologic outcome after thoracic endovascular repair.
      Risk factors for stroke include: (1) history of prior stroke or TIA, (2) chronic renal failure, (3) CT grade IV atheroma (>5 mm) in the aortic arch or proximal descending aorta, (4) wire or catheter instrumentation within the aortic arch or proximal descending aorta in patients who have vulnerable atheroma, (5) coverage of zones 0 to 2, and (6) PAU.
      • Gutsche J.T.
      • Szeto W.
      • Cheung A.T.
      Endovascular stenting of thoracic aortic aneurysm.
      • Ullery B.W.
      • McGarvey M.
      • Cheung A.T.
      • et al.
      Vascular distribution of stroke and its relationship to perioperative mortality and neurologic outcome after thoracic endovascular repair.

      Spinal cord ischemia

      The most devastating complication of TEVAR is SCI leading to infarction.
      Neurologic deficits secondary to TEVAR tend to involve the lower trunk and lower extremities, may lateralize, and range from paraparesis to paraplegia.
      • Findeiss L.K.
      • Cody M.E.
      Endovascular repair of the thoracic aortic aneurysms.
      SCI may be temporary, permanent, immediate, or delayed, and is associated with increased morbidity and mortality.
      • Feezor R.J.
      • Lee W.A.
      Strategies for detection and prevention of spinal cord ischemia during TEVAR.
      In a recent study, Conrad and colleagues
      • Conrad M.F.
      • Ye J.Y.
      • Chung T.K.
      • et al.
      Spinal cord complications after thoracic aortic surgery: long-term survival and functional status varies with deficit severity.
      showed that the 5-year survival for patients with SCI was lower than that in patients with no SCI (25% vs 51%, P<.001).
      In functional terms postoperative SCI may be defined as any neurologic dysfunction, motor or sensory, that occurs in a patient, which did not exist before the thoracic repair and is not attributable to intracranial disorder (ie, stroke or intracranial hemorrhage).
      • Feezor R.J.
      • Lee W.A.
      Strategies for detection and prevention of spinal cord ischemia during TEVAR.
      The injury seen after SCI (anterior spinal artery [ASA] syndrome) is manifested by a loss of motor function, pinprick sensation, and preservation of vibratory and position sense; this can cause autonomic dysfunction, leading to hypotension or neurogenic shock that can further compromise spinal cord perfusion.

      Argalious M. Endovascular aortic repair in the descending thoracoabdominal aorta [abstract 322]. In: Programs and abstracts of the American Society of Anesthesiologists’ Annual Meeting. Chicago, IL, October 15–17, 2011. p. 1–9.

      • Gutsche J.T.
      • Szeto W.
      • Cheung A.T.
      Endovascular stenting of thoracic aortic aneurysm.
      The overall incidence of paraplegia or paraparesis after TEVAR, based on clinical series reported in the literature, is 3.9%.
      • Rizvi A.Z.
      • Sullivan T.M.
      Incidence, prevention, and management in spinal cord protection during TEVAR.
      It is a multifactorial event, with the following contributing risk factors

      Argalious M. Endovascular aortic repair in the descending thoracoabdominal aorta [abstract 322]. In: Programs and abstracts of the American Society of Anesthesiologists’ Annual Meeting. Chicago, IL, October 15–17, 2011. p. 1–9.

      • Fedorow C.A.
      • Moon M.C.
      • Mutch W.A.
      • et al.
      Lumbar cerebrospinal fluid drainage for thoracoabdominal aortic surgery: rationale and practical considerations for management.
      • Sinha A.C.
      • Cheung A.T.
      Spinal cord protection and thoracic aortic surgery.
      :
      • Compromised pelvic and hypogastric/iliolumbar circulation supplying the ASA
        • Previous or concomitant abdominal aortic aneurysm (AAA) repair
        • Injury to the external iliac artery
        • Occlusion of the hypogastric artery
      • Exclusion of critical intercostal arteries supplying the ASA
        • Coverage of thoracic aortic segment of more than 20 cm or distal coverage within 2 cm of the celiac artery
        • Exclusion of T8 to L2 region of the distal thoracic aorta
        • LSCA coverage in patients without a patent circle of Willis
      • Perioperative hypotension
        • Spinal cord perfusion pressure (SCPP) less than 70 mm Hg; risk factor for immediate and delayed SCI
      • Severe atherosclerosis of the thoracic aorta
        • Increased risk of emboli to the ASA and athermanous occlusion of the intercostal arteries
      • Renal failure
        • Compromised collateral blood supply to the spinal cord

      Strategies to reduce the incidence of SCI following TEVAR

      • Optimize oxygen delivery. Maintain a normal cardiac index and hemoglobin.

        Argalious M. Endovascular aortic repair in the descending thoracoabdominal aorta [abstract 322]. In: Programs and abstracts of the American Society of Anesthesiologists’ Annual Meeting. Chicago, IL, October 15–17, 2011. p. 1–9.

        • Fedorow C.A.
        • Moon M.C.
        • Mutch W.A.
        • et al.
        Lumbar cerebrospinal fluid drainage for thoracoabdominal aortic surgery: rationale and practical considerations for management.
        • Sinha A.C.
        • Cheung A.T.
        Spinal cord protection and thoracic aortic surgery.
        • Acher C.
        It is not just assisted circulation, hypothermic arrest, or clamp and sew.
        • Lima B.
        • Nowicki E.R.
        • Blackstone E.H.
        • et al.
        Spinal cord protective strategies during descending and thoracoabdominal aortic aneurysm repair in the modern era: the role of intrathecal papaverine.
      • Increase the SCPP (ACC/AHA Class IIa recommendation, level of evidence B).
        • Hiratzka L.F.
        • Bakris G.L.
        • Beckman J.A.
        • et al.
        2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
      • Maintain MAP above 80 mm Hg, cerebrospinal fluid (CSF) pressure less than 10 mm Hg, and central venous pressure (CVP) less than 10 mm Hg, and preserve LSCA blood flow.
      • Pharmacologic protection (ACC/AHA Class IIa recommendation, level of evidence B)
        • Hiratzka L.F.
        • Bakris G.L.
        • Beckman J.A.
        • et al.
        2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
        :
        • Reduce excitotoxicity. Infuse naloxone at 1 μg/kg/h.
          • Acher C.
          It is not just assisted circulation, hypothermic arrest, or clamp and sew.
        • Increase blood flow in the spinal cord. Intrathecal papaverine (60 mg) causes vasodilatation, and increases spinal cord blood flow and SCPP.
          • Lima B.
          • Nowicki E.R.
          • Blackstone E.H.
          • et al.
          Spinal cord protective strategies during descending and thoracoabdominal aortic aneurysm repair in the modern era: the role of intrathecal papaverine.

      Hemodynamic manipulation during aortic endograft deployment

      The ascending aorta, aortic arch, and proximal descending thoracic aorta represent a hostile environment for endografts, with tortuous anatomy and forceful hemodynamic forces that make accurate positioning difficult. As a result, adjunctive measures to reduce cardiac output (CO) induce asystole, or decrease HR and MAP are required to assist accurate endograft deployment.
      • Nicolaou G.
      • Forbes T.L.
      Strategies for accurate endograft placement in the proximal thoracic aorta.
      Adjunctive measures include pharmacologic and nonpharmacologic methods.
      • Nicolaou G.
      • Forbes T.L.
      Strategies for accurate endograft placement in the proximal thoracic aorta.
      Pharmacologic agents should be titratable, short acting, and have a rapid onset of action. Adenosine administered as a bolus at a dose of 0.5 to 1.5 mg/kg produces asystole for 20 to 30 seconds. A target HR of 50 to 60 beats/min can be achieved by using esmolol and dexmedetomidine, and a target MAP of 50 to 60 mm Hg can be achieved by using nitroglycerin, clevidipine, propofol, remifentanil, and volatile anesthetics.

      Argalious M. Endovascular aortic repair in the descending thoracoabdominal aorta [abstract 322]. In: Programs and abstracts of the American Society of Anesthesiologists’ Annual Meeting. Chicago, IL, October 15–17, 2011. p. 1–9.

      • Nicolaou G.
      • Forbes T.L.
      Strategies for accurate endograft placement in the proximal thoracic aorta.
      Nonpharmacologic measures include rapid transvenous right ventricular pacing (RVP) and right atrial inflow occlusion. RVP results in the loss of atrioventricular synchrony and a reduction in ventricular filling time, causing a decrease in left ventricular preload, stroke volume, and CO. RVP at a rate of 130 to 180 beats/min can lower the systolic blood pressure (SBP) to 50 to 60 mm Hg, and pacing at 160 to 200 beats/min can reduce the SBP to 20 to 30 mm Hg. RVP is associated with more precise placement at the designated location than with any pharmacologic intervention. Accurate proximal endograft deployment can also be facilitated by temporarily occluding the inferior vena cava, leading to preload reduction and hypotension.
      • Nicolaou G.
      • Forbes T.L.
      Strategies for accurate endograft placement in the proximal thoracic aorta.
      The authors pharmacologically induce hypotension with a β-blocker and a vasodilator for deployments in zones 2, 3, and 4, and use RVP for deployments in zones 0 and 1.
      • Nicolaou G.
      • Forbes T.L.
      Strategies for accurate endograft placement in the proximal thoracic aorta.
      Based on these considerations, the following is recommended in conjunction with standard monitoring
      • Gutsche J.T.
      • Szeto W.
      • Cheung A.T.
      Endovascular stenting of thoracic aortic aneurysm.
      • Miller R.
      Anesthesia for vascular surgery.
      :
      • Blood products to be made immediately available
      • Large-bore peripheral intravenous access combined with a rapid fluid warmer transfuser, for the administration of blood products and fluids
      • Monitoring of urine output; fluid management is directed primarily at maintaining normovolemia
      • A right radial arterial line, which will permit monitoring of BP during repair of the proximal thoracic aorta or distal aortic arch if the LSCA has to be covered. Also, a catheter may be placed percutaneously in the left brachial artery for aortic angiography and/or endograft placement
      • Central venous access for monitoring the right atrial pressure and for the administration of vasoactive drugs to control the circulation
      • Insertion of a spinal drain for CSF drainage (CSFD), and CSF pressure monitoring for spinal cord protection

      Anesthetic Technique

      TEVAR has been successfully performed under both general anesthesia (GA) and regional anesthesia (RA).

      Regional anesthesia

      The advantage of spinal or epidural anesthesia is that it allows the patient to remain awake, avoid tracheal intubation, and provide postoperative pain relief. Disadvantages of RA for TEVAR include patient movement, sympathectomy, and no allowance for TEE and neurophysiologic monitoring.
      • Gutsche J.T.
      • Szeto W.
      • Cheung A.T.
      Endovascular stenting of thoracic aortic aneurysm.

      General anesthesia

      TEVAR is usually performed under GA.

      Argalious M. Endovascular aortic repair in the descending thoracoabdominal aorta [abstract 322]. In: Programs and abstracts of the American Society of Anesthesiologists’ Annual Meeting. Chicago, IL, October 15–17, 2011. p. 1–9.

      • Gutsche J.T.
      • Szeto W.
      • Cheung A.T.
      Endovascular stenting of thoracic aortic aneurysm.
      Advantages include the ability to control ventilation and limit patient movement. Disadvantages of GA include the potential for airway complications and postoperative central nervous system depression from residual anesthetic drugs.
      • Gutsche J.T.
      • Szeto W.
      • Cheung A.T.
      Endovascular stenting of thoracic aortic aneurysm.
      Factors favoring GA include

      Argalious M. Endovascular aortic repair in the descending thoracoabdominal aorta [abstract 322]. In: Programs and abstracts of the American Society of Anesthesiologists’ Annual Meeting. Chicago, IL, October 15–17, 2011. p. 1–9.

      : (1) TEVAR with planned fenestrated or branched endografts, owing to the expected long duration; (2) a need for debranching procedures or for aortic/iliac artery access (through a retroperitoneal incision); (3) planned use of TEE and/or neurophysiologic monitoring; (4) planned hemodynamic manipulations to create a motionless field during stent deployment; and (5) planned central-line placement and/or left brachial artery cannulation.
      Regardless of the mode of anesthesia, the intraoperative anesthetic goals during TEVAR are to provide hemodynamic stability while preserving vital organ perfusion and function, and maintaining intravascular volume, adequate oxygenation, and body temperature. These goals are more important to overall outcome than the choice of anesthetic technique.
      • Findeiss L.K.
      • Cody M.E.
      Endovascular repair of the thoracic aortic aneurysms.

      Argalious M. Endovascular aortic repair in the descending thoracoabdominal aorta [abstract 322]. In: Programs and abstracts of the American Society of Anesthesiologists’ Annual Meeting. Chicago, IL, October 15–17, 2011. p. 1–9.

      • Gutsche J.T.
      • Szeto W.
      • Cheung A.T.
      Endovascular stenting of thoracic aortic aneurysm.
      • Miller R.
      Anesthesia for vascular surgery.

      Specialized Perioperative Monitoring

      Transesophageal echocardiography (ACC/AHA Class IIa recommendation, level of evidence B)

      Intraoperative TEE can provide the following

      Argalious M. Endovascular aortic repair in the descending thoracoabdominal aorta [abstract 322]. In: Programs and abstracts of the American Society of Anesthesiologists’ Annual Meeting. Chicago, IL, October 15–17, 2011. p. 1–9.

      • Hiratzka L.F.
      • Bakris G.L.
      • Beckman J.A.
      • et al.
      2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
      • Gutsche J.T.
      • Szeto W.
      • Cheung A.T.
      Endovascular stenting of thoracic aortic aneurysm.
      : (1) assessment of ventricular function and volume status; (2) diagnosis and confirmation of aortic abnormality; (3) guidance for guide wire, delivery device, and endograft placement within the aorta; (4) classification and detection of endoleaks; (5) verification of aneurysm exclusion by showing static contrast within the aneurysmal sac; and (6) help in identifying proximal and distal stent-graft landing zones, entry and exit points, and true and false lumens of dissections.

      Monitoring of spinal cord function

      The ideal spinal cord monitor should (1) be noninvasive, (2) be simple enough to use that no additional personnel are required, (3) be highly sensitive and specific to changes in the anterior spinal cord, (4) allow standard anesthesia delivery, (5) exhibit no delay in ischemia detection, and (6) be usable in conscious postoperative patients.
      • LeMaire S.A.
      • Ochoa L.N.
      • Conklin L.D.
      • et al.
      Transcutaneous near-infrared spectroscopy for detection of regional spinal ischemia during intercostal artery ligation: preliminary experimental results.

      Neurophysiologic monitoring (ACC/AHA Class IIb recommendation, level of evidence B)

      Sensory evoked potential monitoring

      Somatosensory evoked potentials (SSEPs) are cerebral cortical electrical potentials recorded with scalp electrodes during electrical stimulation of the posterior tibial or peroneal nerves of the lower extremities,
      • Hiratzka L.F.
      • Bakris G.L.
      • Beckman J.A.
      • et al.
      2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
      conducted via the lateral and posterior columns of the spinal cord.
      • Hiratzka L.F.
      • Bakris G.L.
      • Beckman J.A.
      • et al.
      2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
      There are 4 general problems with SSEP monitoring.
      • Miller R.
      Anesthesia for vascular surgery.
      • Achouh P.E.
      • Estrera A.L.
      • Miller III, C.C.
      • et al.
      Role of somatosensory evoked potentials during thoracic and thoracoabdominal aneurysm repair.
      First, sensory monitoring is more likely to detect lateral and posterior sensory column ischemia and is a poor monitor of the anterior motor column. Second, inhaled anesthetics and hypothermia can interfere with SSEP signals. Third, ischemia affects peripheral nerves, and ischemia in the lower extremities delays conduction from the usual stimulation sites.
      • Miller R.
      Anesthesia for vascular surgery.
      Fourth, although SSEPs can reliably exclude SCI with a negative predictive value of 99.2%, their sensitivity for its detection is only 62.5%, with no clinically useful predictive value for delayed-onset paraplegia.
      • Achouh P.E.
      • Estrera A.L.
      • Miller III, C.C.
      • et al.
      Role of somatosensory evoked potentials during thoracic and thoracoabdominal aneurysm repair.

      Transcranial motor-evoked potential monitoring

      Transcranial motor-evoked potential (MEP) monitoring is performed by applying paired stimuli to the scalp overlying the motor cortex. The evoked potentials elicited from this stimulation travel from the motor cortex, through cortical spinal tracts, anterior horn cell, peripheral nerve, and finally to the anterior tibialis muscle, where it is recorded.
      • Miller R.
      Anesthesia for vascular surgery.
      Only electromyogenic responses are specific for the status of the motor neurons in the anterior horn gray matter.
      • Miller R.
      Anesthesia for vascular surgery.
      An interruption in this pathway will result in the loss or reduction of amplitude in the MEPs. The major problem with MEPs is that it requires experienced personnel for interpretation.

      Effects of anesthesia on SSEPs and MEPs

      Central neuraxial anesthesia is contraindicated if SSEP or MEP monitoring is planned.
      • Hiratzka L.F.
      • Bakris G.L.
      • Beckman J.A.
      • et al.
      2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
      When conducting SSEP monitoring, volatile anesthetic concentrations should be maintained at half the minimum anesthetic concentration (MAC) because high volatile anesthetic concentrations attenuate cortical signals.
      • Sinha A.C.
      • Cheung A.T.
      Spinal cord protection and thoracic aortic surgery.
      The amplitude of MEPs are sensitive to neuromuscular blocking agents and inhalational anesthetics. General anesthetic regimens using intravenous infusions of remifentanil, ketamine, propofol, or etomidate without neuromuscular blockade have been shown to maintain satisfactory MEP signals during operation.
      • Gutsche J.T.
      • Szeto W.
      • Cheung A.T.
      Endovascular stenting of thoracic aortic aneurysm.
      • Miller R.
      Anesthesia for vascular surgery.
      • Sinha A.C.
      • Cheung A.T.
      Spinal cord protection and thoracic aortic surgery.

      Supporting evidence for SSEP and MEP monitoring

      A recent study by Keyhani and colleagues
      • Keyhani K.
      • Miller III, C.C.
      • Estrera A.L.
      • et al.
      Analysis of motor and somatosensory evoked potentials during thoracic and thoracoabdominal aortic aneurysm repair.
      compared both MEPs and SSEPs for spinal cord monitoring in extensive descending thoracic and TAAA repairs (N = 233). Both monitoring modalities had a nearly 90% correlation for spinal cord infarction (correlation statistic = 0.896; P<.0001), as well as a 98% negative predictive value for immediate-onset paraplegia. Furthermore, reversible changes in MEPs and SSEPs had no correlation with permanent paraplegia. As such, despite its theoretical advantages, MEP monitoring failed to demonstrate any significant change in clinical management compared with the use of SSEP monitoring alone.
      • Keyhani K.
      • Miller III, C.C.
      • Estrera A.L.
      • et al.
      Analysis of motor and somatosensory evoked potentials during thoracic and thoracoabdominal aortic aneurysm repair.
      In another study, Jacobs and colleagues
      • Jacobs M.J.
      • Mess W.H.
      • Mochtar B.
      • et al.
      The value of motor evoked potentials in reducing paraplegia during thoracoabdominal aneurysm repair.
      reported preventing neurologic deficits in 98% of patients undergoing TAAA repair by using MEP monitoring. Because of a lack of general consensus on the effectiveness and type of monitoring that should be used, current thoracic aortic disease guidelines recommend the use of either SSEP or MEP monitoring as valid strategies for the detection of intraoperative SCI.
      • Hiratzka L.F.
      • Bakris G.L.
      • Beckman J.A.
      • et al.
      2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
      • Ullery B.W.
      • Wang G.J.
      • Low D.
      • et al.
      Neurological complications of thoracic endovascular aortic repair.

      Transcutaneous near-infrared spectroscopy

      Transcutaneous near-infrared spectroscopy (NIRS) is currently used for cerebral oximetry in cardiovascular surgery. NIRS assesses the oxyhemoglobin fraction within a focal area of underlying tissue by measuring the differential absorption of 2 wavelengths of near-infrared light (730 and 810 nm) that reflect deoxyhemoglobin and total hemoglobin concentration.
      • LeMaire S.A.
      • Ochoa L.N.
      • Conklin L.D.
      • et al.
      Transcutaneous near-infrared spectroscopy for detection of regional spinal ischemia during intercostal artery ligation: preliminary experimental results.

      Supporting evidence for NIRS

      LeMaire and colleagues
      • LeMaire S.A.
      • Ochoa L.N.
      • Conklin L.D.
      • et al.
      Transcutaneous near-infrared spectroscopy for detection of regional spinal ischemia during intercostal artery ligation: preliminary experimental results.
      successfully used NIRS in a pig model to detect induced regional SCI, and Moerman and colleagues
      • Moerman A.
      • Van Herzeele I.
      • Vanpeteghem C.
      • et al.
      Near-infrared spectroscopy for monitoring spinal cord ischemia during hybrid thoracoabdominal aortic aneurysm repair.
      used NIRS to detect SCI during a staged hybrid TAAA repair. Nicolaou and colleagues

      Nicolaou G, Murkin J, Forbes T, et al. Use of spinal near-infrared spectroscopy for monitoring spinal cord perfusion in endovascular repair of thoracoabdominal aneurysm [abstract]. In: Outcomes 2009, The Key West Meeting. Barbados, May 27–30, 2009.

      were the first to use NIRS to accurately detect and treat SCI in humans during TEVAR. One probe was placed over the cervical spine as the control, and one was placed over the lower thoracic spine as the area of interest. In the graph shown in Fig. 8, as the MAP was decreased to facilitate stent deployment, the lower cord NIRS saturation decreased. Subsequent CSF drainage improved NIRS. The investigators interpreted this as an improvement in spinal cord perfusion. This patient awoke without a neurologic deficit.

      Nicolaou G, Murkin J, Forbes T, et al. Use of spinal near-infrared spectroscopy for monitoring spinal cord perfusion in endovascular repair of thoracoabdominal aneurysm [abstract]. In: Outcomes 2009, The Key West Meeting. Barbados, May 27–30, 2009.

      In summary, NIRS has the potential to satisfy all the criteria for ideal spinal cord monitoring and to provide continuous, real-time information about spinal cord perfusion and oxygenation.
      Figure thumbnail gr8
      Fig. 8Relationship between mean arterial pressure, cerebrospinal fluid pressure (CSFP), and the near-infrared spectroscopy (NIRS) saturation over the spinal cord region at risk.
      (From Nicolaou G, Murkin J, Forbes T, et al. Use of spinal near-infrared spectroscopy for monitoring spinal cord perfusion in endovascular repair of thoracoabdominal aneurysm [abstract]. In: outcomes 2009, The Key West Meeting. Barbados, May 27–30, 2009.)

      Lumbar CSF pressure monitoring and drainage (ACC/AHA Class I recommendation, level of evidence B)

      The physiologic basis for lumbar CSFD is based on the principle that
      • Hiratzka L.F.
      • Bakris G.L.
      • Beckman J.A.
      • et al.
      2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
      : SCPP = MAP − (CSFP or CVP [whichever is greater]), where SCPP is spinal cord perfusion pressure, MAP the mean aortic pressure, CSFP the cerebrospinal fluid pressure, and CVP the central venous pressure.
      • Hiratzka L.F.
      • Bakris G.L.
      • Beckman J.A.
      • et al.
      2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
      • Fedorow C.A.
      • Moon M.C.
      • Mutch W.A.
      • et al.
      Lumbar cerebrospinal fluid drainage for thoracoabdominal aortic surgery: rationale and practical considerations for management.
      • Sinha A.C.
      • Cheung A.T.
      Spinal cord protection and thoracic aortic surgery.
      Hypoperfusion and ischemia/reperfusion injury may cause spinal cord edema and mediate negative neurotropic substances. CSFD increases SCPP and may restore spinal cord blood flow by decompressing the spinal compartment syndrome caused by spinal cord edema and by removing negative neurotropic substances from the CSF.
      • Kunihara T.
      • Kubota S.
      • Wakasa S.
      Prevention of spinal cord injury after thoracoabdominal aortic aneurysm repair.
      Indications for CSFD include
      • Rizvi A.Z.
      • Sullivan T.M.
      Incidence, prevention, and management in spinal cord protection during TEVAR.
      : (1) anticipated endograft coverage of T9 to T12 (ASA), (2) thoracic aortic coverage of greater than 20 cm, (3) compromised collateral pathways, (4) symptomatic SCI in a patient who did not have a drain placed preoperatively, and (5) extensive aneurysmal disease (type I and II Crawford classification).
      Percutaneous CSFD is performed by inserting a multiorificed, silastic catheter 5 to 10 cm into the subarachnoid space through a 14-gauge Touhy needle, at the L3-L4 or L4-L5 intervertebral interspace. The open end of the catheter is attached to a sterile closed-circuit reservoir, and the lumbar CSFP is measured with a pressure transducer zero-referenced to the midline of the brain. The system should not be attached to a pressurized flush system, and no heparin should be in the fluid priming the transducer system.
      • Fedorow C.A.
      • Moon M.C.
      • Mutch W.A.
      • et al.
      Lumbar cerebrospinal fluid drainage for thoracoabdominal aortic surgery: rationale and practical considerations for management.
      • Ullery B.W.
      • Wang G.J.
      • Low D.
      • et al.
      Neurological complications of thoracic endovascular aortic repair.
      Lumbar CSF can be drained continuously or intermittently in the operating room to achieve a target CSF pressure of less than 10 mm Hg. There is no consensus on the optimal duration of CSF drain management. The authors’ practice is to drain CSF for the first 24 hours after the procedure, to maintain a CSFP of less than 10 mm Hg. If there is no evidence of SCI, the drain is clamped for another 48 hours with continued monitoring of the CSFP and serial neurologic assessments. If the patient remains asymptomatic the drain is then removed 72 hours from the time of insertion.
      • Feezor R.J.
      • Lee W.A.
      Strategies for detection and prevention of spinal cord ischemia during TEVAR.
      • Fedorow C.A.
      • Moon M.C.
      • Mutch W.A.
      • et al.
      Lumbar cerebrospinal fluid drainage for thoracoabdominal aortic surgery: rationale and practical considerations for management.
      • Sinha A.C.
      • Cheung A.T.
      Spinal cord protection and thoracic aortic surgery.
      • Ullery B.W.
      • Wang G.J.
      • Low D.
      • et al.
      Neurological complications of thoracic endovascular aortic repair.
      Contraindications to spinal drain insertion include patient refusal, coagulopathy, and sepsis. Complications of CSFD occur in approximately 1% of patients with spinal drains, with a reported mortality of 0.6%.
      • Fedorow C.A.
      • Moon M.C.
      • Mutch W.A.
      • et al.
      Lumbar cerebrospinal fluid drainage for thoracoabdominal aortic surgery: rationale and practical considerations for management.
      • Ullery B.W.
      • Wang G.J.
      • Low D.
      • et al.
      Neurological complications of thoracic endovascular aortic repair.
      Complications of, and best practices for, CSFD are summarized in Tables 3 and 4.
      Table 3Complications of CSF drainage
      Data from Refs.
      • Fedorow C.A.
      • Moon M.C.
      • Mutch W.A.
      • et al.
      Lumbar cerebrospinal fluid drainage for thoracoabdominal aortic surgery: rationale and practical considerations for management.
      • Sinha A.C.
      • Cheung A.T.
      Spinal cord protection and thoracic aortic surgery.
      • Ullery B.W.
      • Wang G.J.
      • Low D.
      • et al.
      Neurological complications of thoracic endovascular aortic repair.
      Lumbar PunctureCatheter PresenceCSF Drainage
      • Nerve root/spinal cord injury
      • Bleeding/neuraxial hematoma
      • Persistent CSF leak
      • Nerve root irritation
      • Infection: local/meningitis/epidural abscess
      • Catheter fracture
      • Intracranial hypotension/bleeding (subdural or intracerebellar hematoma)
      • Headache
      • Abducens nerve palsy
      Table 4CSF drainage recommendations
      Data from Feezor RJ, Lee WA. Strategies for detection and prevention of spinal cord ischemia during TEVAR. Semin Vasc Surg 2009;22:187–92; and Fedorow CA, Moon MC, Mutch WA, et al. Lumbar cerebrospinal fluid drainage for thoracoabdominal aortic surgery: rationale and practical considerations for management. Anesth Analg 2010;111:46–58.
      Recommendation
      Preoperative
      Coagulation
      • No LMWH for 24 h (high dose), 12 h (low dose); no clopidogrel × 7 d; no ticlopidine × 10 d; no abciximab × 24–48 h; no eptifibatide or tirofiban × 4–8 h; platelets >100 × 103/μL3; INR <1.3; normal aPTT
      Intracranial pressure
      • Avoid placement of spinal drain if patient has evidence of increased intracranial pressure
      Intraoperative
      Insertion of spinal catheter
      • Sterile technique; must be placed by trained individuals familiar with the risks, contraindications, and anatomy pertinent to the catheterization of the spinal canal; avoid placing in area of localized infection
      Awake vs asleep
      • Awake allows for patient feedback (ie, pain/paresthesia)
      Traumatic/bloody tap
      • Discuss with surgeon; consider delaying surgery for 24 h; delay anticoagulation for 60 min
      Hemodynamics
      • MAP to maintain SCPP >70 mm Hg; CVP <10 mm Hg
      Zero transducer
      • Phlebostatic axis to ensure accurate calculation of SCPP
      CSF drainage
      • CSFP <10 mm Hg to maintain SCPP >70 mm Hg, CSFD ≤20 mL/h, intermittent CSFD with continuous monitoring avoids large volumes of CSFD, which may decrease the risk of intracranial hypotension
      Subarachnoid opiates
      • Avoid, as may exacerbate spinal cord ischemia
      Postoperative
      Hemodynamics
      • Avoid hypotension
      New-onset neurologic deficit
      • Worsening SCI vs neuraxial hematoma; increase SCPP; MRI of spinal cord
      Coagulation for drain removal
      • Platelet count >100 × 103/μL3; INR <1.3; normal aPTT; delay removal 2–4 h after last heparin dose; hold heparin 1 h after catheter removal
      Abbreviations: aPTT, activated partial thromboplastic time; CSFD, cerebrospinal fluid drainage; CSFP, cerebrospinal fluid pressure; CVP, central venous pressure; ICH, intracranial hemorrhage; INR, international normalized ratio; LMWH, low molecular weight heparin; MAP, mean arterial blood pressure; MRI, magnetic resonance imaging; SCPP, spinal cord perfusion pressure.

      Supporting evidence for CSFD

      Coselli and colleagues
      • Coselli J.
      • LeMaire S.
      • Koksoy C.
      • et al.
      Cerebrospinal fluid drainage reduces paraplegia after thoracoabdominal aortic aneurysm repair: results of a randomized clinical trial.
      randomized 145 patients undergoing TAAA repair with or without CSFD. Nine patients (13.0%) in the control group developed paraplegia or paraparesis. By contrast, only 2 patients in the CSFD group (2.6%) had deficits develop (P = .03). No patients with CSFD had immediate paraplegia.
      • Coselli J.
      • LeMaire S.
      • Koksoy C.
      • et al.
      Cerebrospinal fluid drainage reduces paraplegia after thoracoabdominal aortic aneurysm repair: results of a randomized clinical trial.
      Two independent meta-analyses by Khan and Stansby
      • Khan S.N.
      • Stansby G.
      Cerebrospinal fluid drainage for thoracic and thoracoabdominal aortic aneurysm surgery.
      and by Cina and colleagues
      • Cina C.S.
      • Abouzahr L.
      • Arena G.O.
      • et al.
      Cerebrospinal fluid drainage to prevent paraplegia during thoracic and thoracoabdominal aortic aneurysm surgery: a systematic review and meta-analysis.
      concluded that CSFD was advantageous in reducing the risk of SCI in open TAA repairs. In recent years, lumbar CSFD has been shown to be beneficial for the prevention and treatment of SCI after TEVAR.

      Argalious M. Endovascular aortic repair in the descending thoracoabdominal aorta [abstract 322]. In: Programs and abstracts of the American Society of Anesthesiologists’ Annual Meeting. Chicago, IL, October 15–17, 2011. p. 1–9.

      • Fedorow C.A.
      • Moon M.C.
      • Mutch W.A.
      • et al.
      Lumbar cerebrospinal fluid drainage for thoracoabdominal aortic surgery: rationale and practical considerations for management.
      • Sinha A.C.
      • Cheung A.T.
      Spinal cord protection and thoracic aortic surgery.
      • Ullery B.W.
      • Wang G.J.
      • Low D.
      • et al.
      Neurological complications of thoracic endovascular aortic repair.
      In a prospective observational study using historical controls, Hnath and colleagues
      • Hnath J.C.
      • Mehta M.
      • Taggert J.B.
      • et al.
      Strategies to improve spinal cord ischemia in endovascular thoracic aortic repair: outcomes of a prospective cerebrospinal fluid drainage protocol.
      showed a significant decrease in the incidence of postoperative spinal cord injury with TEVAR when CSFD was used.

      Biochemical markers for the detection of SCI

      The protein S100β, which is present in high concentrations in glial and Schwann cells, is released during acute neuronal injury and has been shown to correlate with a decrease in transcranial MEPs.
      • Feezor R.J.
      • Lee W.A.
      Strategies for detection and prevention of spinal cord ischemia during TEVAR.
      Kunihara and colleagues
      • Kunihara T.
      • Kubota S.
      • Wakasa S.
      Prevention of spinal cord injury after thoracoabdominal aortic aneurysm repair.
      observed that after TAAA repair, levels of neurotoxic excitatory amino acids, proinflammatory cytokines, and S-100β were found to be higher in the CSF of patients with postoperative SCI than in patients without SCI. Another marker, glial fibrillary acidic protein, was found to be higher in the CSF of patients with SCI. This marker was detectable before the development of clinical symptoms.
      • Feezor R.J.
      • Lee W.A.
      Strategies for detection and prevention of spinal cord ischemia during TEVAR.
      A limitation of biochemical markers remains the lack of specificity for spinal cord injury versus an intracerebral event.

      Postoperative Management

      Neurologic examination should be performed immediately on emergence from GA. Any neurologic deficit detected should be considered to be SCI until proven otherwise, and a neurologist should examine the patient.

        Management of SCI following TEVAR

        Argalious M. Endovascular aortic repair in the descending thoracoabdominal aorta [abstract 322]. In: Programs and abstracts of the American Society of Anesthesiologists’ Annual Meeting. Chicago, IL, October 15–17, 2011. p. 1–9.

        • Gutsche J.T.
        • Szeto W.
        • Cheung A.T.
        Endovascular stenting of thoracic aortic aneurysm.
        • Fedorow C.A.
        • Moon M.C.
        • Mutch W.A.
        • et al.
        Lumbar cerebrospinal fluid drainage for thoracoabdominal aortic surgery: rationale and practical considerations for management.
        • Sinha A.C.
        • Cheung A.T.
        Spinal cord protection and thoracic aortic surgery.
        • Acher C.
        It is not just assisted circulation, hypothermic arrest, or clamp and sew.
        • Ullery B.W.
        • Wang G.J.
        • Low D.
        • et al.
        Neurological complications of thoracic endovascular aortic repair.

      • 1.
        Optimize oxygen delivery
        • a.
          Optimize the cardiac index
        • b.
          Hematocrit 30% or greater
      • 2.
        Maximize SCPP
        • a.
          Maintain a perioperative MAP above 90 to 110 mm Hg through volume expansion and by using an α-agonist (eg, norepinephrine, phenylephrine, vasopressin)
        • b.
          Therapeutic CSFD to maintain CSFP below 10 mm Hg
        • c.
          CVP less than 10 mm Hg
      • 3.
        Reduce neurotoxic excitatory neurotransmitters
        • Nicolaou G.
        • Forbes T.L.
        Strategies for accurate endograft placement in the proximal thoracic aorta.
        • a.
          Naloxone infusion at 1 μg/kg/h, continue for 48 hours postoperatively
      • 4.
        Serial neurologic examination
        • a.
          To assess for improvement or worsening of the neurologic deficit
      • 5.
        Magnetic resonance imaging
        • a.
          To exclude a spinal hematoma or any other spinal cord abnormality

      Summary

      TEVAR has revolutionized thoracic aortic surgery and has increased the options available to the aortic specialist in treating thoracic aortic disease. Although current devices do not allow perfusion of intercostal arteries, TEVAR is less invasive and is associated with a decrease in perioperative morbidity and mortality when compared with OSR. In patients with: (1) traumatic thoracic aortic injury, (2) acute complicated TBADs, (3) DTAAs larger than 5.5 cm with feasible anatomy, and (4) ruptured DTAAs with suitable anatomy, TEVAR is considered the treatment of choice. Ideally, TEVAR should be performed in specialized aortic centers providing a full range of diagnostic and treatment options, using a multidisciplinary team approach.
      However, despite encouraging results from a large number of publications in recent years, the long-term durability of TEVAR still remains largely unknown. Follow-up with serial imaging studies is necessary to detect device failure. As endovascular techniques and technology continue to evolve, TEVAR use will continue to expand at a rapid pace. Randomized controlled trials to examine the long-term efficacy and safety of TEVAR in comparison with open surgery and conservative medical management are necessary to better define patient selection and the role of TEVAR in the treatment of thoracic aortic disease.

      Acknowledgments

      The authors wish to acknowledge Ms Brieanne McConnell for her assistance in facilitating literature searches, retrieval, and citation management.

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