Objectives: We sought to define the current anatomic barriers to thoracic aortic aneurysm (TAA) stent grafting to guide future device development.
Methods: All patients presenting with TAA requiring repair were evaluated for endovascular repair during a 4-year period (2000 to 2004). The TAAs evaluated were those beginning distal to the left common carotid artery (LCCA) and ending proximal to the celiac artery. All patients in whom endovascular repair was indicated underwent cross-sectional imaging by computed tomography angiography and three-dimensional modeling of their thoracic and abdominal arterial anatomy. Patients were evaluated for endovascular TAA repair in the context of the inclusion/exclusion criteria of pivotal United States Food and Drug Administration trials of the Gore TAG and Medtronic Talent devices. Anatomic requirements included >or=20 mm of suitable proximal and distal neck length, and proximal and distal neck diameters of 20 to 42 mm. These trials allowed the use of femoral or iliac access, including the use of conduits, and permitted stent graft coverage of the left subclavian artery (LSA) after preliminary carotid-subclavian bypass. Patients rejected for medical reasons or who died during evaluation were not included in the review.
Results: A total of 126 patients (73 men, 53 women) with TAA located between the LCCA and celiac artery were screened for endovascular repair, and 33 (26%) were rejected for anatomic reasons. The remaining 93 patients underwent endografting (59 Talent, 34 TAG). Rejection was not significantly different by gender (16/73 men, 17/53 women, P = .22, NS). Most patients (28/33) were rejected for more than one criterion. Hostile proximal neck characteristics were the most prevalent reason for disqualification, despite the ability to cover the LSA to extend the proximal seal zone. Many of these patients (16/28) also had distal neck anatomy unsuitable for grafting. Overall, 19 patients had hostile distal necks. Difficulties with vascular access (diseased or tortuous iliac arteries, or a small caliber aorta) that could not be overcome even by use of conduits occurred in a significant fraction of patients (10/33).
Conclusions: Most patients with a TAA located between the LCCA and the celiac artery can be treated by endovascular repair. Patients excluded from TAA stent graft protocols for anatomic reasons most commonly have hostile proximal neck features that preclude endovascular repair with currently available devices. Transposition of arch vessels to facilitate greater use of existing stent grafts or development of new stent graft designs are needed to expand the applicability of TAA endovascular repair.