Mortality risk factors from converting off-pump coronary artery bypass to on-pump coronary artery bypass

Abstract

Introduction: A number of large-scale retrospective studies revealed that off-pump coronary artery bypass (OPCAB) was superior to on-pump coronary artery bypass (ONCAB). The aim of the study was to investigate risk factors for mortality when OPCAB is converted to ONCAB. Methods: Patients who underwent OPCAB conversion to ONCAB at the Beijing Anzhen Hospital between January 2003 and January 2013 were assigned to the non-survivor and survivor groups. Background demographics, illness history and preoperative, intraoperative and postoperative variables were compared. Results: Of the 247 cases, 15.4% of the patients died. Patients in the non-survivor group were older and more frequently had diabetes mellitus (DM), arrhythmia, myocardial infarction (MI) in the past 30 days (all p<0.05) and MI combined with mitral regurgitation (p<0.0001); they more frequently had bigger left ventricular end-diastolic dimension (p=0.0019), greater fall in blood pressure, ventricular fibrillation for longer periods, longer conversion time and bypass graft occlusion. All patients in the non-survivor group received intra-aortic balloon pump compared to 89.5% in the survivor group and extracorporeal membrane oxygenation was more common. Left main coronary artery disease (OR=4.431, 95%CI: 2.440-8.048, p<0.0001), blood pressure decline ⩽40 mmHg (OR=0.509, 95%CI: 0.447-0.580, p<0.0001) and time for conversion to ONCAB ⩾20 min were independently associated with mortality. Rates of postoperative complications, such as renal failure, cerebral infarction or hemorrhage, MI and redo sternotomy, were higher in the non-survivor group. Conclusions: Conversion from OPCAB to ONCAB is associated with high mortality. Risk factors include left main artery disease and duration of blood pressure decline >40 min.