Death, mode of death, morbidity and requirement for rehospitalization during 2 years after coronary artery bypass grafting in relation to preoperative ejection fraction

OBJECTIVE: To describe the impact of ejection fraction on the prognosis during 2 years after coronary artery bypass grafting (CABG). PATIENTS: All patients in western Sweden who underwent CABG without concomitant valve surgery between June 1988 and June 1991. RESULTS: In all, 2121 patients were operated upon and information on ejection fraction was available for 1961 patients (92%). Of these patients, 178 (9%) had an ejection fraction < 40%, 517 (26%) an ejection fraction of 40-59% and 1266 (65%) an ejection fraction > or = 60%. In these groups the mortalities during the first 30 days after CABG were 5.1, 4.3 and 2.2%, respectively (P < 0.01). The corresponding values for mortalities between 30 days and 2 years were 7.7, 4.3 and 3.3%, respectively (P < 0.01). Patients with a lower ejection fraction were more frequently men and more frequently had a history of cardiovascular disease. In multivariate analysis the preoperative ejection fraction was an independent predictor for total 2-year mortality. Patients with a low ejection fraction died more frequently in association with ventricular fibrillation. Morbidity was, with the exception of that for rehospitalization due to heart failure and infection, not associated significantly with the preoperative ejection fraction. CONCLUSION: During the 2 years after CABG a low preoperative ejection fraction was associated with a higher mortality, but the association with morbidity was more complex.