Branched endografts for thoracoabdominal aneurysms

Abstract

Purpose: Endovascular management of thoracoabdominal aneurysms has been studied since 2001, with marked advances allowing for the treatment of complex anatomic situations including chronic aortic dissections, tortuous anatomy, and extensive aneurysms that involve the visceral segment, aortic arch, and iliacs as well. However, the technology is not widely disseminated, and a thorough understanding of the engineering principles, imaging techniques, and devices available is required.

Methods: Reinforced fenestrated branches coupled with balloon expandable stent grafts, and side-arm branch designs mated with self-expanding stent grafts have been used. Pure fenestrated designs were used for juxtarenal aneurysms, whereas thoracoabdominal aneurysms were treated with reinforced fenestrated branches or hybrid devices including side-arm branches and reinforced fenestrated branches. Intraoperative fusion techniques have been used since 2009, whereby preoperative computed tomographic data are fused with intraoperative fluoroscopy. Long-term survival in accordance with extent of disease was assessed with life table analysis techniques, and differences were analyzed using the log rank test. Intermediate-term data pertaining to patency related to both types of branches and paraplegia have been evaluated and previously published.

Results: A total of 406 patients with thoracoabdominal aneurysms and 227 patients with juxtarenal aneurysms have been enrolled in a prospective study. Perioperative and 2-year survival were most closely related to extent of initial disease and were estimated to be 1.8% and 82% for juxtarenal aneurysms, 2.3% and 82% for type IV, and 5.2% and 74% for type II and III thoracoabdominal aneurysms at 24 months, respectively. When patients undergoing endovascular repair (ER group) were matched with those having contemporary surgical repair (SR group) for anatomic disease extent, mortality was similar at 30 days (5.7% ER vs 8.3% SR; P = .2) and at 12 months (15.6% ER vs 15.9% SR; P = .9). Paraplegia risk was also similar between the 2 groups (4.3% ER vs 7.5% SR, respectively; P = .08). Among the 633 patients, there were 5 (0.8%) late ruptures at a mean of 18 months after treatment, of which 4 were fatal. They were attributed to component separation (n = 3), a remote aneurysm rupture proximal to the endovascular repair, and a failed surgical polyester graft distal to the repair. Reinforced fenestrated branch patency, when coupled with balloon-expandable stent grafts, was 97.8% at a mean follow-up of 15 months. Side-arm branch occlusion occurred in only 1 case, within 24 hours of the procedure. New imaging tools resulted in a marked reduction in the average contrast dose (>50%).

Conclusions: Intermediate-term results with multiple methods of endovascular repair of thoracoabdominal aneurysm indicate the technical feasibility of the procedure and show great promise in patients considered at high risk for open surgery. The intermediate-term patency and survival are excellent, and ruptures are exceedingly uncommon. However, mortality and spinal cord ischemia risks are still considerable with this technique.