Coronary Artery Bypass Grafting in Patients With Low Ejection Fraction

Abstract

Patients with low ejection fraction (EF) are at a higher risk for postoperative complications and mortality. Our objective was to assess the effect of low EF on clinical outcomes after coronary artery bypass grafting (CABG). We analyzed 55,515 patients from New York State database who underwent CABG between 1997 and 1999. Patients were stratified into 1 of the 4 EF groups: Group I (EF< or =20%), Group II (EF 21% to 30%), Group III (EF 31% to 40%), and Group IV (EF>40%). History of previous myocardial infarction, renal failure, and congestive heart failure were higher in patients with low EF (all P<0.001). Group I experienced a higher incidence of postoperative respiratory failure (10.1% versus 2.9%), renal failure (2.5% versus 0.6%), and sepsis (2.5% versus 0.6%) compared with Group IV. In-hospital mortality was significantly higher in Group I (6.5% versus 1.4%; P<0.001). Multivariate analysis showed hepatic failure [odds ratio (OR), 11.2], renal failure (OR, 4.1), previous myocardial infarction (OR, 3.4), reoperation (OR, 3.4), emergent procedures (OR, 3.2), female gender (OR, 1.7), congestive heart failure (OR, 1.6), and age (OR, 1.04) as independent predictors of in-hospital mortality in the low EF group. The discharges to home rate were significantly lower in Group I versus Group IV (73.1% and 87.7%, respectively; P<0.001). Patients with low EF are sicker at baseline and have >4 times higher mortality than patients with high EF. However, outcomes are improving over time and are superior to historical data. Therefore, CABG remains a viable option in selected patients with low EF.