Advances in Thoracic Endovascular Aortic Repair: Introduction

Volume 21, Number 4

Winter 2009

Advances in Thoracic Endovascular Aortic Repair: Introduction

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ince US Food and Drug Administration approval in 2005 for the treatment of descending thoracic aortic aneurysms, thoracic endovascular aortic repair (TEVAR) has revolutionized the field of thoracic aortic surgery. Although no randomized studies exist to this point, accumulating clinical experience from around the world has confirmed the feasibility and the safety of this new treatment paradigm, with results comparable to conventional open repair. Furthermore, TEVAR provides patients previously considered prohibitively high risk for conventional repair an alternative surgical option. With its widespread acceptance in the treatment of aneurysmal disease, innovative investigators have further expanded the indications of use with off-label application of TEVAR in various other thoracic aortic pathologies, including dissections, traumatic injuries, aortic arch, and thoracoabdominal aortic aneurysms. Perhaps, many have argued that this technology may have its most significant clinical contribution in these highest risk categories of thoracic aortic pathologies. In this issue of the Seminars of Thoracic and Cardiovascular Surgery, experts in thoracic aortic surgery have provided a thorough review of the technology as well as a discussion of various innovative off-label applications of TEVAR. Each section not only represents a new surgical paradigm in the treatment of its respective thoracic aortic pathology, but it reflects the exciting evolution of thoracic aortic surgery as we continue to advance our previous clinical accomplishments and ultimately improve patient care. However, we should be cautious in our enthusiastic embrace of this new treatment paradigm, and we must remain critical with continual assessment of the accumulating data. Dr. Davies begins with a thorough review of the current literature regarding on-label use of TEVAR in the treatment of descending thoracic aortic aneurysms. A summary of the 3 US Investigational Device Exemption studies leading to the Food and Drug Association approval of the Gore TAG endoprosthesis (W.L. Gore, Flagstaff, AZ), Medtronic, Talent Thoracic endoprosthesis (Medtronic Vascular, Santa Rosa, CA), and the Cook Zenith TX2 (Bloomington, IN) are discussed. As clinical experience continues to accumulate, questions 1043-0679/09/$-see front matter © 2009 Elsevier Inc. All rights reserved. doi:10.1053/j.semtcvs.2009.12.004

and concerns regarding device durability are valid. Studies examining midterm data are further discussed in this section. Currently, conventional surgical reconstruction of aortic arch aneurysms remains a clinical challenge. Despite improvement with surgical technique, total arch reconstruction is associated with significant perioperative morbidity and mortality, particularly in high-risk patients. Dr. Bavaria and I provide a discussion of the innovative use of TEVAR in aortic arch aneurysms and the evolving field of hybrid arch repair. Since its introduction, hybrid arch repair has evolved from simple “debranching” operations to complex, concomitant open arch reconstruction and endovascular repair of the descending thoracic aorta. At Penn, we have described a new classification of hybrid arch repair based on the extent of aneurysm and the landing zone anatomy. For thoracoabdominal aortic aneurysms, open reconstruction in high-risk surgical candidates remains to be associated with significant morbidity and mortality. Although fenestrated and branched endograft systems have been developed, widespread application has not occurred, with availability only limited to a few centers. Given the more readily available standard endograft devices, hybrid approaches to thoracoabdominal aortic aneurysms in high-risk surgical candidates have been adopted worldwide. Dr. Hughes and Dr. McCann have provided a discussion of their experience at Duke University with the hybrid approach to the treatment of thoracoabdominal aortic aneurysms. So called the visceral “debranching” operation, the hybrid repair has become an important alternative option to patients with thoracoabdominal aortic aneurysms considered prohibitively high risk for conventional open repair. Endoleaks remain a major clinical concern in endovascular therapy. Dr. Gleason provides a thorough discussion and review of the literature with regard to the clinical significance and management of endoleaks. As longer follow-up accumulates, the incidence and management of endoleaks will define the long-term durability of this treatment paradigm. In the remaining sections, the application of TEVAR in acute aortic syndromes is discussed. Even in contemporary series, conventional open repair in these clinical scenarios 339

340 remains associated with significant morbidity and mortality. For distal aortic dissections (Stanford type B, DeBakey III), the use of TEVAR has been increasingly reported from many centers of excellence. Dr. Bhamidipati and Dr. Ailawadi discuss the current data regarding the application of TEVAR in acute distal thoracic aortic dissections. Controversy currently exists with regard to the use of TEVAR in acute uncomplicated distal aortic dissections. In contrast, accumulating data have been supportive in its use when distal aortic dissections are associated with life-threatening complications. Although short-term data have been promising, longer follow-up will be needed before definitive conclusion can be made. Nonetheless, the dramatic reduction in perioperative mortality in these early series has resulted in its widespread application worldwide. After proximal dissection repair, aneurysmal degeneration of the distal aortic dissection remains a clinical challenge. Surgical reconstruction remains associated with significant operative morbidity and mortality. The fate of the distal aorta after proximal aortic dissection repair and its clinical effect on distal aortic remodeling remain to be answered. Furthermore, strategies to treat the distal residual dissection at the time of the proximal reconstruction as an attempt to positively alter aortic remodeling and prevent aneurysmal degeneration has remained equally controversial. My colleagues Dr. Desai and Dr. Pochettino

W.Y. Szeto and J.E. Bavaria discuss the application of TEVAR in the treatment of the residual distal aortic dissection during proximal dissection repair. The role and potential benefit of distal thoracic aortic endovascular repair on the fate of the distal aorta is thoroughly discussed. Finally, Dr. Brinster discusses the use of TEVAR in the treatment of blunt thoracic aortic injuries. Although success with conventional open repair has been reported historically, these procedures can be associated with significant morbidity and mortality, especially in patients severely injured. Indications, technical challenges, and clinical results using TEVAR in the treatment of blunt thoracic aortic injuries are thoroughly discussed in this section. Since its introduction, the application of thoracic endovascular aortic repair has evolved with the creativity of innovative investigators and surgeons. In the near future, technologic advances have the potential to achieve totally endovascular platform in the treatment of the various ascending, arch, and thoracoabdominal aortic pathologies. And as long-term data accumulate, TEVAR may become the preferable therapeutic option for many of the thoracic aortic pathologies. Wilson Y. Szeto, MD Joseph E. Bavaria, MD Guest Editors