Preoperative angiotensin-converting enzyme inhibitors protect myocardium from ischemia during coronary artery bypass graft surgery

Abstract

Coronary artery bypass graft surgery may result in perioperative myocardial injury during cardioplegic arrest. Angiotensin-converting enzyme (ACE) inhibitors protect the myocardium from ischemia in several clinical conditions, but no previous study has attempted to evaluate the impact of preoperative ACE inhibitor therapy on myocardial protection in patients undergoing coronary artery bypass graft surgery. A propensity score-based analysis of 481 patients undergoing isolated on-pump coronary artery bypass graft surgery was carried out, among which 245 patients received preoperative ACE inhibitors and 236 patients did not. Perioperative myocardial injury was assessed by ischemia marker cardiac troponin I (cTnI). Preoperative cTnI concentration was similar for patients receiving ACE inhibitors and those who did not [0.1 ng/ml (0.06-0.19) versus 0.1 ng/ml (0.06-0.19); P = 0.3]. Postoperative cTnI peak concentration was lower in patients receiving preoperative ACE inhibitors [1.6 ng/ml (1.05-3.4) versus 2.4 ng/ml (1.13-6.10); P = 0.0006]. After adjusting for propensity score and covariates, preoperative ACE inhibitors were found to decrease postoperative cTnI peak concentration (beta = -0.12; P = 0.004). Other independent predictors of postoperative cTnI peak concentration were female gender, emergency surgery, number of distal anastomoses and aortic cross clamp time. Overall, operative mortality rate was 16/481 (3.3%). Patients receiving preoperative ACE inhibitors had a lower rate of postoperative myocardial infarction (2.0 versus 4.2%; P = 0.25) and low cardiac output syndrome (3.6 versus 6.3%; P = 0.24). ACE inhibitors prior to surgery confer added myocardial protection during surgical revascularization. Prospective, randomized clinical trials will be necessary to better define the role of ACE inhibitors in improving outcomes when they are prescribed prior to coronary artery bypass graft surgery.