ObjectiveTo systematically evaluate the effect of leucocyte-depleted blood cardioplegia on myocardial protection in adult patients underwent cardiac surgery with extracorporeal circulation. MethodsWe searched PubMed, EMbase, The Cochrane Library (Issue 2, 2015), CBM, VIP, WanFang Data and CNKI databases from inception to March 1st 2015, to collect randomized controlled trials (RCTs) about leucocyte-depleted blood cardioplegia for adult patients underwent cardiac surgery. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies. Then, meta-analysis was conducted by using RevMan 5.3 software. ResultsA total of 17 RCTs including 637 patients were included. The results of meta-analysis showed that: Compared with the control group, the leucocyte-depleted blood cardioplegia could significantly reduce the level of postoperative CK-MB peak value (SMD=-0.75, 95%CI -1.12 to -0.39, P<0.0001), the utilization of inotropic drugs after operation (OR=0.51, 95%CI 0.29 to 0.92, P=0.02), and perioperative incidence of arrhythmia (OR=0.51, 95%CI 0.31 to 0.84, P=0.009). However, no significant differences were found in the incidence of perioperative myocardial infarction (OR=1.0, 95%CI 0.20 to 5.13, P=1.00), peri-operative mortality (peto-OR=0.51, 95%CI 0.05 to 4.94, P=0.56) and ICU stay (SMD=-0.06, 95%CI -0.32 to 0.21, P=0.68) between the two groups. ConclusionCurrent evidence shows, leucocyte-depleted blood cardioplegia could effectively reduce the myocardial injury in adult patients underwent cardiac surgery with extracorporeal circulation, but in reducing perioperative severe complications and mortality, improving the long-term prognosis in patients, the protective effect of leucocyte-depleted blood cardioplegia is yet to be evaluated. In addition, due to the limitation of quality and quantity of included studies, the above conclusion still need to be verified by conducting larger sample, high quality, multi-central RCTs.