Off pump versus conventional on pump coronary artery bypass: a review

Despite many years of clinical and experimental research, the contribution of Cardiopulmonary Bypass (CPB) and cardioplegic arrest to morbidity and mortality following cardiac surgery remains unclear. In the last few years, Off-Pump Coronary Artery Bypass grafting (OPCAB) has gained widespread attention as an alternative technique to conventional On-Pump Coronary Artery Bypass grafting (ONCAB). It has provided an opportunity to compare the operations, in similar patient groups, with or without CPB and cardioplegic arrest. Although initial studies performed on low risk patients preferably with single vessel disease showed favorable outcome, we currently lack larger properly randomized high quality studies which show definite benefit. Proponents of off-pump surgery state that the avoidance of the CPB leads to significantly reduced myocardial ischemia-reperfusion injury, post-operative systemic inflammatory response, postoperative pulmonary complications, hospital stay and cost, a feature that may improve the clinical and economical outcomes. However, perfection in surgical technique, completeness of revascularization and whether the off pump method leads to improved outcome are still burning issues. In this review, OPCAB is found to be significantly better than the ONCAB in reducing cost, hospital stay, blood transfusion requirements, incidence of post-operative pulmonary complications, systemic inflammation and post-operative atrial fibrillations in most of the studies. The comparison show almost equivocal results regarding mortality, survival, quality of life, re-intervention rate, risk of stroke, cognitive decline and GI complication.