Is minimized extracorporeal circulation effective to reduce the need for red blood cells transfusion in coronary artery bypass grafting? Meta-analysis of randomized controlled trials

Perioperative red blood cell (RBC) transfusion is the single factor most consistently associated with an increased risk of postoperative morbid events after isolated coronary artery bypass grafting (CABG), and each unit of RBC transfused is associated with incrementally increased risk for adverse outcome.1 Miniaturized extracorporeal circulation (mini-ECC) has been proposed to limit perioperative blood product use. Mini-ECC consists of a closed ECC system with no cardiotomy suction or venous reservoir. The rationale is to avoid air–blood contact and minimize priming volume, thus reducing hemostasis alteration and intraoperative hemodilution. However, there is still controversy on whether such a strategy effectively reduces postoperative RBC transfusion, with some reports showing no evident benefit. We conducted a meta-analysis on available randomized controlled trials (RCTs) to evaluate whether mini-ECC decreases the risk of postoperative RBC transfusion compared with conventional ECC in patients undergoing CABG.