Survival After Coronary Artery Bypass Grafting in Patients With Preoperative Heart Failure and Preserved vs Reduced Ejection Fraction

IMPORTANCE Data on the prognostic consequence of heart failure (HF) with preserved ejection fraction in patients undergoing coronary artery bypass grafting (CABG) are limited and inconclusive. OBJECTIVE To investigate the survival after CABG in patients with preoperative HF and preserved ejection fraction (pEF) vs reduced ejection fraction (rEF). DESIGN, SETTING, AND PARTICIPANTS Swedish nationwide population-based cohort study that included all patients who underwent primary isolated CABG between January 1, 2001, and December 31, 2013, from the SwedishWeb-system for Enhancement and Development of Evidence-based care in Heart disease Evaluated According to Recommended Therapies (SWEDEHEART) register, with follow-up for all-cause mortality in March 2014. Information regarding baseline characteristics, all-cause mortality, and readmissions for HF was obtained from national health data registers. Preserved EF was defined as at least 50%. MAIN OUTCOMES AND MEASURES The primary outcomewas all-cause mortality. A secondary outcome measure was a combination of all-cause mortality and readmission for HF. RESULTS The study included 41 906 patients, 37 234 without known HF (27 165 with pEF and 10 069 with rEF) and 4672 with HF (1216 with pEF and 3456 with rEF). Their mean (SD) age was 67.4 (9.3) years, and 21.0% were female. During a mean (SD) follow-up time of 6.0 (3.3) years, 19.0%(7943 of 41 906) of patients died, including 13.2%(3574 of 27 165) with no HF and pEF, 24.6%(2476 of 10 069) with no HF and rEF, 33.9% (412 of 1216) with HFpEF, and 42.9%(1481 of 3456) with HFrEF. The multivariable-adjusted hazard ratios for death were 1.47 (95% CI, 1.40-1.56), 1.62 (95% CI, 1.46-1.80), and 2.29 (95% CI, 2.14-2.44) in patients with no HF and rEF, patients with HFpEF, and patients with HFrEF compared with patients with no HF and pEF. The findings were similar for the combined outcome of all-cause mortality and readmission for HF. The multivariable-adjusted hazard ratios for death within 30 days of surgery were 2.25 (95% CI, 1.86-2.73), 1.83 (95% CI, 1.26-2.66), and 2.52 (95% CI, 1.99-3.19) in patients with no HF and rEF, patients with HFpEF, and patients with HFrEF. CONCLUSIONS AND RELEVANCE A history of HF was an important risk factor for poor short-term and long-term outcomes after CABG regardless of preoperative EF. Reduced EF more than doubled the risk of early death after CABG.