Myocardial revascularization in patients with low ejection fraction ≤35%:: Effect of pump technique on early morbidity and mortality

Background and aim: Left ventricular dysfunction is an important predictor of in-hospital mortality. Surgical risk among these patients remains high. The present study is conducted to evaluate the difference in early morbidity and mortality among patients with compromised left ventricular function (LVF) after myocardial revascularization using either off-pump or on-pump coronary artery bypass graft. Methods: Between April 2000 and April 2004, 150 patients with ejection fraction (EF) <= 35% underwent isolated coronary artery bypass grafting. Eighty-four patients underwent conventional bypass (mean EF 30.1% +/- 4.2) and 66 patients had off-pump coronary artery bypass (mean EF 27.5% +/- 5.5). Different variables (preoperative, intraoperative, and postoperative) were evaluated and compared. Determination of operation risk was done using EuroSCORE. Patients who underwent OPCAB were more risky due to a high percentage of associated comorbidities, mean EuroSCORE was 12.96 +/- 13.21 in comparison to 8.47 +/- 10.22 in CCAB. Results: The mean operative mortality was 8.7%. Patients who underwent OPCAB had a lower operative mortality than CCAB (6.1% vs. 10.7%) inspite of a higher preoperative predicted risk score. Completeness of revascularization was higher among the CCAB group (85.7% vs. 69.7%; p = 0.01). Subsequently, the mean number of grafts was significantly higher among this group (3.4 +/- 0.7 vs. 2.0 +/- 0.9; p < 0.001). On the other hand, morbidity was significantly higher in CCAB (35.7% vs. 19.7%; p = 0.03). However, the incidence of both myocardial infarction and atrial fibrillation was more among OPCAB. Conclusions: Patients with left ventricular dysfunction are high-risk group. These patients can benefit from myocardial revascularization using either off-pump or conventional CABG, but both are associated with a higher mortality and morbidity than those with normal ventricle. The use of off-pump CABG resulted in better clinical outcome and mortality, but less number of grafts performed than those with conventional CABG especially in patients with lowest EF.