Preoperative intra-aortic balloon pump to reduce mortality in coronary artery bypass graft: a meta-analysis of randomized controlled trials

Introduction: The intra-aortic balloon pump is routinely used in cardiac surgery; however, its impact on outcome is still a matter of debate and several randomized trials have been published recently. We perform an updated meta-analysis of randomized controlled trials that investigated the use of preoperative intra-aortic balloon pump in adult patients undergoing coronary artery bypass grafting. Methods: Potentially eligible trials were identified by searching the Medline, Embase, Scopus, ISI Web of Knowledge and The Cochrane Library. Searches were not restricted by language or publication status and were updated in August 2014. Randomized controlled trials on preoperative intra-aortic balloon pump in patients undergoing coronary artery bypass grafting either with or without cardiopulmonary bypass were identified. The primary end point was mortality at the longest follow-up available and the secondary end point was 30-day mortality. Results: The eight included randomized clinical trials enrolled 625 patients (312 to the intra-aortic balloon pump group and 313 to control). The use of intra-aortic balloon pump was associated with a significant reduction in the risk of mortality (11 of 312 (3.5%) versus 33 of 313 (11%), risk ratio = 0.38 (0.20 to 0.73), P for effect = 0.004, P for heterogeneity = 0.7, I-square = 0%, with eight studies included). The benefit on mortality reduction was confirmed restricting the analysis to trials with low risk of bias, to those reporting 30-day follow-up and to patients undergoing coronary artery bypass graft surgery with cardiopulmonary bypass. Conclusions: Preoperative intra-aortic balloon pump reduces perioperative and 30-day mortality in high-risk patients undergoing elective coronary artery bypass grafting.