Low left ventricular ejection fraction, complication rescue, and long-term survival after coronary artery bypass grafting

Abstract

ObjectivesTo evaluate the association between low left ventricular ejection fraction (LVEF), complication rescue, and long-term survival after isolated coronary artery bypass grafting. MethodsNational cohort study of patients who underwent isolated coronary artery bypass grafting (2000-2016) using Veterans Affairs Surgical Quality Improvement Program data. Left ventricular ejection fraction was categorized as ≥35% (n = 55,877), 25%-34% (n = 3893), or <25% (n = 1707). Patients were also categorized as having had no complications, 1 complication, or more than 1 complication. The association between LVEF, complication rescue, and risk of death was evaluated with multivariable Cox regression. ResultsAmong 61,477 patients, 6586 (10.7%) had a perioperative complication and 2056 (3.3%) had multiple complications. Relative to LVEF ≥35%, decreasing ejection fraction was associated with greater odds of complications (25%-34%, odds ratio, 1.30 [1.18-1.42]; <25%, odds ratio, 1.65 [1.43-1.92]). There was a dose–response relationship between decreasing LVEF and overall risk of death (≥35% [ref]; 25%-35%, hazard ratio, 1.46 [1.37-1.55]; <25%, hazard ratio, 1.68 [1.58-1.79]). Among patients who were rescued from complications, there were decreases in 10-year survival, regardless of LVEF. Among those rescued after multiple complications, LVEF was no longer associated with risk of death. ConclusionsWhile decreasing LVEF is associated with post-coronary artery bypass grafting complications, patients rescued from complications have worse long-term survival, regardless of left ventricular function. Prevention and timely treatment of complications should remain a focus of quality improvement initiatives, and future work is needed to mitigate their long-term detrimental impact on survival.