Acetylsalicylic Acid Is Associated With a Lower Prevalence of Ascending Aortic Aneurysm and a Decreased Aortic Expression of Cyclooxygenase 2

Background Acetylsalicylic acid (ASA) therapy has been associated with a reduced prevalence and growth rate of abdominal as well as intracranial aneurysms, but the relationship between ASA and ascending aortic aneurysm formation remains largely unknown. The aim of the present study was to investigate whether ASA therapy is associated with a lower prevalence of ascending aortic aneurysm in a surgical cohort. Methods and Results One thousand seven hundred patients undergoing open‐heart surgery for ascending aortic aneurysm and/or aortic valve disease were studied in this retrospective cross‐sectional study. Aortic dilatation was defined as an aortic root or ascending aortic diameter ≥45 mm. Medications were self‐reported by the patients in a systematic questionnaire. Cyclooxygenase gene expression was measured in the intima‐media portion of the ascending aorta (n=117). In a multivariable analysis, ASA was associated with a reduced prevalence of ascending aortic aneurysm (relative risk, 0.68 [95% CI, 0.48–0.95],P =0.026) in patients with tricuspid aortic valves, but not in patients with bicuspid aortic valves (relative risk, 0.93 [95% CI, 0.64–1.34],P =0.687). Intima‐media cyclooxygenase expression was positively correlated with ascending aortic dimensions (P <0.001 for cyclooxygenase‐1 andP =0.05 for cyclooxygenase‐2). In dilated, but not nondilated tricuspid aortic valve aortic specimens, ASA was associated with significantly lower cyclooxygenase‐2 levels (P =0.034).Conclusions Our findings are consistent with the hypothesis that ASA treatment may attenuate ascending aortic aneurysmal growth, possibly via cyclooxygenase‐2 inhibition in the ascending aortic wall and subsequent anti‐inflammatory actions.