Off-pump coronary artery bypass in multi-vessel disease: effect of ejection fraction on early and midterm mortality and morbidity

Abstract

Aim: Left ventricular function is an independent predictor of operative mortality. The outcome of myocardial revascularization is greatly affected by the severity of impairment of cardiac function. The present study was undertaken to find the early and midterm mortality and morbidity among patients with different degrees of myocardial function undergoing off-pump bypass.

Methods: Hundred and forty two patients with isolated coronary revascularization were divided into three groups according to left ventricle ejection fraction (LVEF). Forty eight patients with LVEF<30% (group I), 48 patients with LVEF between 30-40% (group II), and 46 patients with LVEF >40% (group III). Clinical, operative and post operative outcome were compared. Patients were followed up to find midterm survival and control of symptoms.

Results: The mean age for the patients observed was 56.5+/-9.8 years. Preoperative predicted mortality according to euroSCORE was much higher in group I due to high incidence of preoperative heart failure and recent myocardial infarction. The extent of coronary vessel involvement was similar among the three groups, but those in group III had more single vessel disease. The number of grafts performed per patient was lowest in group I (1.7+/-0.6) and highest in group III (2.0+/-0.6) P=0.03. Overall hospital mortality was 4.2%.The mean euroSCORE of patients who died was 18.7+/-22.5. All in-hospital mortality was among patients who belonged to the high risk group I, 6 (12.5%). Morbidity was similar among all groups. The incidence of myocardial infarction, atrial fibrillation, and acute renal failure were slightly higher in group I; 95.6% of patients were followed up for 7-69 months (mean 27.6+/-17.6). The incidence of angina in group I, II, and III was 20%, 6.5%, and 2.2%. Symptomatic heart failure was seen in 17.5% in group I, 6.5% in group II, and 2.2% in group III. Cardiac interventions among group I, II, III was 12.5%, 4.3% and 2.3% respectively. Redo coronary artery bypass CABG was higher in group II (4.3%) compared to 2.5% in group I. Late mortality was similar among all groups.

Conclusion: Off-pump bypass can be used safely among patients with different degrees of myocardial function. The results of surgery were better than the preoperative predicted euroSCORE. Early mortality and morbidity were directly related to ejection fraction .This is true only when LVEF is below 30%. Midterm mortality was similar among different risk groups.