A Phase I Evaluation of the Safety of the TriVascular Stent-Graft System in the Treatment of Abdominal Aortic Aneurysms

Inclusion Criteria: * Male or infertile female * Have signed an informed consent form. * Are considered an appropriate candidate for open surgical repair of an abdominal aortic aneurysm. * at least one of the following: Abdominal aortic aneurysm \>= 4.5 cm in diameter; aneurysm has increased in size by 0.5cm in last 6 months; maximum diameter of aneurysm exceeds 1.5 times the transverse dimension of an adjacent normal aortic segment; saccular aneurysm larger than 3 cm. * Have patent iliac or femoral arteries that allow endovascular access to the aneurysmal site with a 17F Delivery Catheter. Exclusion Criteria: * A dissecting, acutely ruptured, or leaking aneurysm, or an acute vascular injury due to trauma. * A need for emergent surgery. * contraindication to undergoing angiography. * A Thoracic aortic aneurysm that requires treatment. * Presence of thrombus or atheroma in proximal aortic neck covering \> 50% of the endoluminal surface. * Presence of diffuse atherosclerotic disease in either common iliac artery that reduces the iliac artery diameter to \<7mm. * Congenital abnormalities in which the placement of the stent-graft will cause occlusion of major arterial flow. Such abnormalities should be evaluated(e.g. angiography or CT) prior to treatment. * Unstable angina * Morbid obesity or other clinical conditions that severely inhibit x-ray visualization of the aorta. * Connective tissue disease (e.g., Marfan's or Ehlers-Danlos syndrome.) * Hypercoagulable state. * Contraindication for anticoagulation. * Acute renal failure. * Active systemic infection. * less than 18 years of age. * Life expectancy less than 1 year. * Current, or anticipated participation within 1 year, in another research study involving an investigational device or new drug (with the exception of participation in the Lifeline Registry of Endovascular Therapy). * Other medical, social, or psychological issues that in the opinion of the investigator preclude them from receiving this treatment, and the procedures and evaluations pre- and post-treatment.