Background: Coronary artery spasm (CAS) is a well-known endothelial dysfunction, and a major cause of vasospastic angina (VSA). The renin-angiotensin system (RAS) is known to be closely associated with endothelial function. However, there are only a few studies that investigated the impact of RAS inhibitor on long-term clinical outcomes in VSA patients.
Methods and results: A total of 3349 patients with no significant coronary artery disease, diagnosed with CAS by acetylcholine provocation test were enrolled for this study. Significant CAS was defined as having ≥70% narrowing of the artery after incremental injections of 20, 50, and 100 μg of acetylcholine into the left coronary artery. Patients were divided into 2 groups according to whether the prescription included RAS inhibitor or not (RAS inhibitor group: n=666, non-RAS inhibitor group; n=2683). To adjust for any potential confounders that could cause bias, propensity score matching (PSM) analysis was performed using a logistic regression model. After PSM analysis, 2 matched groups (524 pairs, n=1048 patients, C-statistic=0.845) were generated and their baseline characteristics were balanced. During the 5-year clinical follow-up, the RAS inhibitor group showed a lower incidence of recurrent angina (8.7% versus 14.1%, P=0.027), total death (0.0% versus 1.3%, P=0.045), and total major adverse cardiovascular events (1.0% versus 4.1%, P=0.026) than the non-RAS inhibitor group.
Conclusions: Chronic RAS inhibitor therapy was associated with lower incidence of cardiovascular events in VSA patients in the 5-year clinical follow-up.
Keywords: acetylcholine; angina; angiotensin converting enzyme inhibitor; angiotensin receptor blocker; coronary artery spasm; renin–angiotensin system; vasospasm.
© 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.