Meta-analysis of the effects of preoperative renin-angiotensin system inhibitor therapy on major adverse cardiac events in patients undergoing cardiac surgery.

The purpose of this meta-analysis was to assess the role of preoperative renin-angiotensin system inhibitor (RASI) therapy on major adverse cardiac events (MACE) in patients undergoing cardiac surgery. The Medline, Cochrane Library and Embase databases were searched for clinical studies published up to May 2014. Studies that evaluated the effects of preoperative RASI therapy in cardiac surgery were included. Odds ratio (OR) estimates were generated under a random-effects model. After a literature search in the major databases, 18 studies were identified [three randomized prospective clinical trials (RCTs) and 15 observational trials] that reported outcomes of 54 528 cardiac surgery patients with (n = 22 661; 42%) or without (n = 31 867; 58%) preoperative RASI therapy. Pool analysis indicated that preoperative RASI therapy was not associated with a significant reduction of early all-cause mortality [OR: 1.01; 95% confidence interval (CI) 0.88-1.15, P = 0.93; I(2) = 25%], myocardial infarction (OR: 1.04; 95% CI 0.91-1.19, P = 0.60; I(2) = 16%), or stroke (OR: 0.93; 95% CI 0.75-1.14, P = 0.46; I(2) = 38%). Meta-regression analysis confirmed that there was a strong negative correlation between the percentage of diabetics and early all-cause mortality (P = 0.03). Furthermore, preoperative RASI therapy significantly reduced mortality in studies containing a high proportion of diabetic patients (OR: 0.84; 95% CI 0.71-0.99, P = 0.04; I(2) = 0%). In conclusion, our meta-analysis indicated that although preoperative RASI therapy was not associated with a lower risk of MACE in cardiac surgery patients, it might provide benefits for diabetic patients.