Chapter 50: Endovascular Therapy for the Treatment of Thoracic Aortic Disease

INTRODUCTION

Patients with thoracic aortic disease pose many challenges. Frequently, these patients are older and present with multiple comorbidities. Additionally, the posterior location of the descending thoracic aorta requires a large thoracotomy incision, with its own inherent morbidity.

The modern surgical treatment of thoracic aortic disease began in the 1950s, when successful treatment utilizing segmental resection and graft replacement was first reported by Swan, Lam, DeBakey, and Etheridge.^1-3 Soon thereafter, DeBakey and Cooley reported the first successful repair of an ascending aortic aneurysm using cardiopulmonary bypass.⁴ Cardiopulmonary bypass and commercially available tube grafts were the mainstays of our surgical armamentarium for the next 30 years. Improved diagnostic capabilities, surgical techniques, and perioperative care have resulted in improved outcomes, even as the risk profile has worsened.^5,6 In an effort to limit the morbidity of these operations,^7,8 endovascular techniques emerged as an attractive alternative. Originally devised for high-risk patients, and following on developments directed toward aneurysms of the abdominal aorta, thoracic endovascular stent-graft technology has rapidly evolved. Although originally intended for repair of atherosclerotic thoracic aortic aneurysms,^9–11 thoracic stent-graft applications have been expanded to the treatment of multiple pathologies, including acute and chronic aortic dissections, penetrating atherosclerotic aortic ulcers, and thoracic aortic trauma.^12-19 Results have steadily improved, and long-term durability has been encouraging; however, the necessity for long-term follow-up remains,^20-22 with obvious financial implications.

HISTORY

Endovascular stent-graft technology, initially targeting the abdominal aortic aneurysm, was introduced by Parodi.²³ Balloon-expandable stents, sewn inside the ends of a vascular tube graft, were placed within the aneurysmal aorta, excluding the aneurysm sac. Simultaneously, at Stanford University Medical Center, a collaborative effort between interventional radiologists and cardiovascular surgeons proved highly synergistic and resulted in a homemade thoracic stent graft.

Self-expanding Gianturco Z stents (Cook Company, Bloomington, IN) were fastened together and covered with a woven Dacron graft (Meadox-Boston Scientific, Natick, MA; Fig. 50-1), and then compressed into a 28-French introducer sheath. The first homemade thoracic graft was implanted in the descending thoracic aorta in 1992 after Institutional Review Board (IRB) approval was obtained. Subsequently, a high-risk trial was approved for patients with thoracic aortic aneurysms who were deemed nonsurgical candidates.²⁴ Thirteen such patients were treated utilizing stent grafts, customized-designed for each patient. Placement of these stents was successful in all patients, with complete thrombosis of the aneurysm sac reported in 12 of the 13 patients. At 1 year, there were no deaths, paraplegia, strokes, or distal embolization.

Feasibility having been established, IRB approval was obtained for a subsequent trial of 103 patients, 60% of whom were deemed unfit for conventional open surgical repair.²⁵ Using the ...