Endovascular Treatment of TAAA and Aortic Arch Aneurysms Using Fenestrated and Branched Stent Grafts

To assess the feasibility and safety and to evaluate clinical outcomes of endovascular repair of complex aortic aneurysms (thoracoabdominal aortic aneurysms and aortic arch aneurysms) in patients at high risk for open surgery in two study arms: 1. TAAA (thoracoabdominal aortic aneurysm) Study Arm: To assess the feasibility and safety and to evaluate clinical outcomes of endovascular stent graft implantation using either a multibranched stent graft (Off-the-Shelf TAAA Device) or custom-manufactured physician-specified branched and/or fenestrated stent graft (Physician-Specified TAAA Device) to treat aortic aneurysms involving the mesenteric and/or renal arteries (TAAA) in patients at high risk for open surgery. 2. Aortic Arch Study Arm: To assess the feasibility and safety and to evaluate clinical outcomes of endovascular stent graft implantation using 1) physician-specified aortic arch stent graft device with up to 3 antegrade and/or retrograde branches or 2) a physician-specified retrograde left subclavian branch stent-graft with double or triple wide scallop to the left common carotid artery\] to treat aortic aneurysms involving the aortic arch in patients at high risk for open surgery.