Purpose To evaluate the long-term results associated with the Zenith Alpha thoracic stent-graft, which was designed to address challenging access vessel anatomy. Materials and Methods A retrospective analysis was conducted of 44 consecutive patients (mean age 72.5±8.3 years; 25 men) treated in a single center between August 2010 and October 2014 with a minimum follow-up of 5 years in survivors. The Zenith Alpha thoracic stent-graft was used to treat thoracic aortic aneurysms (n=37), thoracoabdominal aortic aneurysm (n=5), or penetrating aortic ulcer (n=2). Ten patients (23%) were American Society of Anesthesiologists class IV, and 9 (20%) had nonelective procedures. Access vessel anatomy was demanding (mean minimum diameter 5.4 mm, tortuosity index 1.3). The primary endpoint at 5 years was ongoing clinical success (freedom from aneurysm-/procedure-related death, secondary intervention, type I or III endoleak, infection, thrombosis, aneurysm expansion, rupture, or conversion). Secondary endpoints were freedom from all-cause mortality, device migration, stent fractures, fabric erosions, endoleaks, neurological events, and access vessel complications. Results The ongoing clinical success was 84% (37 of 44 patients) owing to 4 aneurysm-related deaths (9%), 3 type I or III endoleaks (1 in a deceased patient), and 1 aneurysm expansion without detectable endoleak. There were 3 access vessel complications (7%), and no postoperative neurological events. Migration was observed in 2 cases (5%). There were no stent fractures or fabric tears. Conclusion Despite the alterations in stent-graft design and material to reduce profile, the Zenith Alpha thoracic stent-graft showed favorable long-term results even in multimorbid patients with demanding iliac anatomy.