Inclusion Criteria:

All patients with an AAA determined to require non-urgent repair after assessment by one of the participating surgeons will be considered. Patients must meet two eligibility criteria: Medical and Anatomic.

Medical Fitness for surgery will mean that the patient is a candidate for elective open repair, and has none of the exclusion criteria listed below.

Anatomic Eligibility will be judged by the endovascular measurement team, and will be based on a score of < 3 on the following scale. (This scale was developed at our centre and is currently being validated.)

1. Neck Length (20 - 15 mm = 1; 14 – 10 mm = 2)
2. Quality of Neck (Thrombus 90 -180 º = 1, 181-270 º = 2; calcification 90 -180 º = 1; 181-270 º = 2)
3. Presence/absence side branches (IMA or lumbar vessels = 1; IMA and lumbar vessels or other = 2)
4. Landing zone (aneurysmal or occlusive disease = 1; aneurysmal and occlusive disease = 2;
5. Degree of calcification of aorta (25 – 50% calcification = 1; > 50% = 2)
6. Access (stenosis = 1; stenosis and tortuosity =2)
7. Stenting of accessory renal arteries necessary
8. Embolization of internal iliac artery necessary

Definition of Surgical Experts

Expertise in endovascular surgery will be determined by completion of a vascular residency at a credentialed academic centre, a period of study in a formal training programme dedicated to acquiring endovascular expertise, and experience with at least 60 previous EVAR procedures.30

Expertise in open aortic repair will require completion of an accredited vascular surgery residency programme and demonstration of expertise by having completed at least 100 consecutive elective AAA repairs in their career.32

Endovascular Measurement Team The Endovascular Measurement team consists of at least one vascular surgeon with expertise in endovascular surgery, at least one vascular fellow in his/her first or second year of training and a representative from an endovascular graft specialist who is familiar with graft measurement and deployment. This team, blinded to patient demographics and surgical fitness, will judge anatomic eligibility.

Exclusion Criteria:

1. Exclusion due to Medical Risk: Patients with severe cardiac or respiratory disease that limits their activities of daily living and would make them ineligible for open repair. BMI greater than 45. Any known diagnosis or condition that renders a lift span of less than 2 years based on available and tolerable treatments.
2. Exclusion due to Aneurysm Factors: Patients with ruptured or symptomatic aneurysms requiring urgent surgery. Any aneurysm that extends proximal to the renal arteries (suprarenal), involves the renal arteries or is less than 15mm distal to the level of the lowest renal artery.
3. Exclusion due to Operative Factors: Patients with multiple previous laparotomies making open repair contraindicated due to adhesions (a ‘hostile abdomen’). Any patients with stomas or exteriorized bowel. Patients with previous abdominal radiation, Fitz-Hugh-Curtis, or history of other conditions that would render open operative intervention contraindicated.