A Comparison of Success Rate in Off-Pump Coronary Artery Bypass Grafting Surgery among Patients with Varying Preoperative Left Ventricular Ejection Fractions: Retrospective Observational Study

Abstract

Background: Off-pump coronary artery bypass grafting (OPCAB) is an alternative to coronary artery revascularization and avoids the complications of cardiopulmonary bypass (CPB). The procedure’s success, however, depends on intraoperative hemodynamic stability. Preoperative cardiac function can predict the tolerance to compromised hemodynamics during cardiac surgery. Inability to manage hypotension and low cardiac output while manipulating the heart is the most frequent cause of intraoperative conversion to CPB. Objective: The authors investigated the effects of the preoperative left ventricular ejection fraction (LVEF) on the success of OPCAB surgery and the relation of intraoperative factors to the success of OPCAB surgery. Material and Methods: Medical records of 284 patients who underwent OPCAB surgery in Ramathibodi Hospital between January 2015 and December 2017 were retrospectively reviewed. Preoperatively, the patients were classified into groups 1 to 4 based on LVEFs of 50% to 70%, 40% to 49%, 30% to 39%, and <30%, respectively. Preoperative characteristics were collected. Intraoperative success of OPCAB surgery, application of inotropes, vasopressor, fluid, and intra-aortic balloon pump (IABP), and post-operative outcomes were analyzed and compared among the four LVEF groups. Results: No significant differences in success of OPCAB surgery emerged among the four groups (p=0.430). Intraoperative requirements of IABP were significantly higher for LVEF <30% patients (p=0.001). In addition, the time to extubation was significantly delayed (p=0.001) and the LVEF <30% patients stayed longer in intensive care unit (ICU) (p=0.002) when compared with the good LVEF patients. There were no significant differences in the operative time, amount of intravenous fluid, blood transfusion requirement, or blood loss among the groups. There were no significant differences in major postoperative morbidities. Conclusion: OPCAB surgery can be performed successfully in patients with severe cardiac dysfunction (LVEF <30%) without significant differences from LVEF ≥30% patients, although the need for an intraoperative IABP device and inotropic drugs for hemodynamic support were greater and the extubation times and ICU stays were longer. Keywords: Coronary artery bypass graft; Left ventricular ejection fraction; Off-pump CABG; OPCAB; Poor cardiac function