This proposal is for the pilot study that will inform the conduct of a larger prospective randomized controlled trial to guide perioperative work up and the cost/utility of CTCA (high definition CT coronary angiography.)

This proposal is for a pilot study that will inform the conduct of a prospective, blinded randomized controlled trial designed to determine the cost effectiveness of an algorithm for pre operative cardiac risk stratification that uses coronary CT angiography. In addition perioperative and long-term cardiac event rate will be recorded to determine if there is any difference in these rates between the 2 groups.

Inclusion Criteria:

• patients being considered for a complex aortic surgery and undergoing medically indicated contrast enhanced CT aortic angiography of the chest abdomen and pelvis

Exclusion Criteria:

• Patients with contraindications to undergoing CT coronary angiography
• coronary revascularization within the last six months
• renal dysfunction in whom the treating physician has decided a contrast enhanced CT scan is not warranted as part of the routine clinical work up

All patients being considered for a complex aortic surgery and undergoing medically indicated contrast enhanced CT aortic angiography of the chest abdomen and pelvis will be includedRaw data from CT coronary angiography will be available from all patients.