Miniaturized extracorporeal circulation versus off-pump coronary artery bypass grafting: A meta-analysis of randomized controlled trials

Background: Controversies exist whether off-pump coronary artery bypass (OPCAB) is superior to miniaturized extracorporeal circulation (MECC) in reducing deleterious effects of cardiopulmonary bypass as only a number of smaller randomized controlled trials (RCT) currently provide a limited evidence base. The main purpose of conducting the present meta-analysis was to overcome the expected low power in RCTs in an attempt to establish whether MECC is comparable to OPCAB. Methods: A MEDLINE/PubMed search was conducted to identify eligible RCTs. A pooled summary effect estimate was calculated by means of Mantel-Haenszel method. Results: The search yielded 7 RCTs included in this meta-analysis enrolling 271 patients in the OPCAB group and 279 in the MECC group. The OPCAB and MECC groups were comparable in terms of incidence of in-hospital mortality (Risk Difference [RD] 0.01; 95%CI -0.02, 0.03; P=0.55; I²=0%), stroke (RD -0.01; 95%CI -0.05, 0.04; P=0.69; I²=0%), need for renal replacement therapy (RD 0.00; -0.06, 0.06; P=1; I²=0%), postoperative atrial fibrillation (RD -0.03; -0.17, 0.10; P=0.64; I²=0%), re-exploration for bleeding (RD -0.01; 95%CI -0.03, 0.02; P=0.65; I²=0%), transfusion rate (RD -0.01; 95%CI -0.03, 0.02; P=0.65; I²=0%) and the amount of blood loss (weighted mean difference -25mL; 95%CI -71, 21; P=0.28; I²=0%). Conclusions: Using a meta-analytic approach, MECC achieves clinical results comparable to OPCAB including postoperative blood loss and blood transfusion requirement. On the basis of our findings, MECC should be considered as a valid alternative to OPCAB in order to reduce surgical morbidity of conventional cardiopulmonary bypass.