Conversions in Off-pump Coronary Artery Bypass Grafting: Analysis and Outcome

Background: Off-pump coronary artery bypass graft (CABG) surgery is supposed to reduce perioperative mortality and morbidity compared with on-pump coronary bypass graft surgery. The causes of hemodynamic collapse during off-pump coronary artery bypass (OPCAB) remain scarcely defined. We present an analysis of 7 cases who were converted to conventional CABG due to sustained hemodynamic collapse or else, during elective offpump CABG. Method: During a 12-month period, we performed 77 elective OPCAB procedures through a sternotomy, constituting 56.2% of the total CABG procedures performed. Six patients (1.6%) experienced hemodynamic collapse intra-operatively and one (0.23%) electively requiring immediate cardiopulmonary bypass. Preoperative characteristics, intraoperative data, and postoperative outcome were retrospectively reviewed. Results: In all cases, improvements in intra-operative technique and/or judgment could be made retrospectively. Six of these patients were converted in emergency, and one electively to cardiopulmonary bypass. Three (3/77) patients had an unstable course and did not survive operation. Conclusions: The causes of hemodynamic collapse during elective OPCAB were ischemic, mechanical, or a combination of both. Based on these results, strong consideration should be given for a planned strategy of CPB in high risk patients.