Coronary artery aneurysms associated with ascending aortic aneurysms and abdominal aortic aneurysms: pathophysiologic implications.

BACKGROUND: Coronary artery aneurysms (CAA) are seen in 1-5% of angiograms. Aneurysmal coronary disease has been thought to be a variant of atherosclerotic coronary artery disease (CAD) in most patients, but this has not been systematically studied.

METHODS: To better understand the pathophysiology of CAA, we reviewed the cardiac catheterization films of 403 patients with ascending thoracic aortic aneurysms and 74 patients with abdominal aortic aneurysms (AAA) who underwent surgery for their aortic aneurysms at our institution. Coronary aneurysms had diameters 1.5-fold that of a reference segment.

RESULTS: The incidences of CAA in patients with ascending aneurysms and AAA were 17% and 16% respectively (P = 0.92). CAAs in the ascending group were larger (mean diameter 5.9 vs. 5.0 mm, P = 0.12) with larger reference vessel size (3.1 vs. 2.6 mm, P = 0.03). CAAs in the patients with ascending aneurysms were less likely to be CAD-associated within the same vessel (12% vs. 75%, P < 0.001). This difference remained significant after controlling for the presence of generalized CAD. No other differences in CAAs between the two groups were found. Within the ascending aneurysm group, the only clinical variable independently associated with CAA was bicuspid aortic valve (OR 0.47, 95% confidence interval 0.25-0.89, P = 0.02). The majority of patients with CAA in the ascending aortic aneurysm population did not have CAD or any other previously identified cause of CAA.

CONCLUSIONS: There is a high incidence of CAA in patients with aortic aneurysms. In patients with ascending aortic aneurysms there is likely a mechanism distinct from CAD that causes CAAs.