Results and predictors of early and late outcome of coronary artery bypass graft surgery in patients with ejection fraction less than 20%

Background. - Severely depressed left ventricular ejection fraction (EF ≤ 20%) has historically been a major risk factor for morbidity and mortality in medically and surgically managed coronary artery disease. Recent studies have suggested that outcomes in patients with EF less or equal to 20% undergoing coronary artery bypass graft (CABG) surgery are improving, but the trend in the outcomes remains unclear. Methods. - We retrospectively analysed prospectively collected data from 2909 consecutive patients undergoing isolated CABG between January 1998 and August 2006. One hundred and eighty five patients (6.4%) had an ejection fraction less or equal to 20%. Primary outcome measures for this study included hospital mortality, major postoperative complications, and long-term survival. Results. - The median age in the overall patient population was 65 years (interquartile range 58-73) and 69% (n=2015) of patients were male. The overall hospital mortality among our study population was 2.3% (n=67). The mortality among patients with EF less or equal to 20 was 5% (n=11) compared to 2% (n=56) in patients with EF above 20% (p=0.001). The proportion of patients with a high EuroSCORE (> 9%) was significantly greater in the group with EF less or equal to 20% (49%) than in the group with EF above 20% (20%). EF Less or equal to 20% was not shown by multivanable logistic regression analysis to be an independent predictor of operative mortality. Survival rates at one year were 85 ± 2.8%, 93 ± 0.9%, and 98% ± 0.3% for patients with EF less or equal to 20%, over 20 - 40% and greater than 40% respectively; and at five years: 72 ± 0.4%, 81 ± 0.2% and 89 ± 0.1%, respectively (p < 0.001). Conclusion. - We demonstrate acceptable mortality rates in patients with an EF less or equal to 20%, and show that EF less or equal to 20% does not appear to be an independent predictor of hospital mortality in our practice. Incremental changes in practice including improved patient selection and peroperative management may have reduced the impact of EF less or equal to 20% on mortality following CABG.