Timing of conversion of Off-Pump CABG to On-Pump CABG is the most important factor determining the outcome of the converted patients

BackgroundOff-Pump Coronary Artery Bypass Graft (CABG) surgery is purposed to reduce perioperative mortality and morbidity compared with On-pump CABG. However some of those patients who were planned for Off-Pump CABG need to be converted to On-Pump CABG. Emergency conversion to cardiopulmonary bypass in Off-Pump CABG is recognized to increase operative mortality and morbidity. We aimed to determine the incidence of conversion, predictor factors, outcome of converted patients and the effect of timing of conversion on the outcome of converted patients.MethodsIn this study, we conducted a retrospective review of 374 consecutive patients who were planned for Off-Pump CABG from July 2009 to June 2015. This review included the preoperative characteristics, operative and post-operative outcomes as well as the timing of conversion either before hemodynamic collapse or after hemodynamic collapse.ResultsOut of 374 patients who were planned for Off-Pump coronary artery bypass grafting 16 patients required conversion to cardiopulmonary bypass with incidence (4.3%). Out of those 16 patients, 10 patients converted to On-Pump before hemodynamic collapse and 6 patients were converted to On-Pump after hemodynamic collapse. Analysis of the preoperative characteristics showed that, the presence of mild to moderate mitral regurgitation, chronic obstructive pulmonary disease (COPD) and left ventricular ejection fraction less than 40% are risk factors for conversion of Off-Pump CABG to On-Pump CABG. Operative mortality was 25% in conversion group and 1.7% in non-conversion group (P < 0.001). All of mortality of the conversion group was in the delayed conversion group while mortality in early conversion group was 0.0%. Respiratory failure, use of IABP and ICU stay were significantly higher in conversion group as compared with non-conversion group, they were (37.5% vs 3.4%), (25% vs 0.6%) and (6.5 ± 5.0 vs 2.3 ± 1.1) respectively.ConclusionPatients who are intended for Off-Pump strategy and then require conversion to On-Pump have significantly higher operative mortality and morbidity than completed OPCAB. Time of conversion plays an important role in the outcome of converted patients; we concluded that delayed conversion is associated with poor surgical outcome, however early conversion before hemodynamic collapse have better outcome. Based on these results, strong considerations should be given for patients who are planned for Off-Pump CABG and have risk factors for conversion to CPB. These patients should be thoroughly monitored with early and elective conversion to On-pump CABG before hemodynamic collapse occurs.