Does Magnesium-Supplemented Cardioplegia Reduce Cardiac Injury? A Meta-Analysis of Randomized Controlled Trials

ABSTRACT Background Magnesium is often used to supplement cardioplegic solutions during cardiopulmonary bypass due to its cardioprotective effect during ischemia and reperfusion. The aim of this meta‐analysis was to evaluate the effects of magnesium‐supplemented cardioplegia versus an inactive (placebo) control cardioplegia on reducing cardiac injury after cardiac arrest surgery, as found by randomized, controlled trials. Methods The Medline, Cochrane Library, and Chinese literature databases (CJFD, CBM, CSJD, Wanfang) were comprehensively searched for reports of randomized, controlled trials (RCTs) evaluating magnesium‐supplemented cardioplegic solutions. The clinical parameters and outcomes of interest were the incidence of postoperative low cardiac output, auto‐rebeating rate, ICU stay length, new onset postoperative atrial fibrillation, peak value of CK‐MB (and/or cTnI), incidence of myocardial infarction, and in‐hospital mortality. Results Ten trials, with a total of 1214 patients, were included. The frequency of low cardiac output, inotropic utilization, and myocardial infarction, as well as auto‐rebeating rate, length of ICU stay and in‐hospital mortality, were similar between the two groups. There was a marginal reduction in the incidence of new‐onset postoperative atrial fibrillation in the magnesium‐supplemented cardioplegia group. Conclusions The advantage of magnesium‐supplemented cardioplegia, compared with cardioplegia without magnesium, remains unconvincing based on the current evidence. The decision to add magnesium to the cardioplegic solution to a patient undergoing cardiac arrest surgery should be carefully considered. doi: 10.1111/jocs.12518 (J Card Surg 2015;30:338–345)