Abstract 9521: Improvement of Left Ventricular Ejection Fraction After Surgical Revascularization in Patients Eligible for Implantable Cardioverter Defibrillator

Abstract

Introduction: Left ventricular ejection fraction (LVEF) ≤35% is the cornerstone criterion for implantable cardioverter-defibrillator (ICD) eligibility. But improvement in LVEF may occur in ICD-eligible patients after coronary artery bypass graft surgery (CABG). Methods: We studied the incidence, predictors, and outcomes of LVEF improvement among patients with LVEF ≤35% who underwent CABG as part of the Surgical Treatment for Ischemic Heart Failure (STICH) trial and had pre- and post-operative (4 months) LVEF assessment using the same cardiac imaging modality. Improvement in LVEF was defined as post-operative EF >35% and >5% absolute improvement from baseline. Results: Of the 427 patients (mean age 62±10 and 50 women), 125 (29.2%) had LVEF improvement from 26.8%±5.8% to 43.3%±6.5%; p<0.001. Improvement in LVEF occurred in 20% and 38% of patients with pre-operative LVEF <25% and 30-35%, respectively (Figure). Post-operative improvement in LVEF was 2.20 times more likely in patients with pre-operative LVEF ≥25% (95% CI 1.41-3.43; p<0.001) than those with pre-operative EF <25%. The odds of post-operative LVEF improvement were 1.96 times higher (95% CI 0.91-4.23, p=0.09) in patients with myocardial viability. After adjusting for age, sex, and pre-operative LVEF, improvement in LVEF was associated with a 42% lower risk of all-cause mortality (HR 0.58, 95% CI 0.35-0.96; p=0.03) and 69% lower risk of heart failure mortality (HR 0.31, 95% CI 0.11-0.87; p=0.03). Conclusions: Nearly 1/3 rd of patients with LVEF ≤35% who underwent CABG had a significant improvement in left ventricular systolic function, obviating the need for primary prevention ICD implantation. Post-operative LVEF improvement was associated with a lower risk of death. These results provide patients and clinicians data on the likelihood of ICD eligibility after CABG and support the practice of reassessment of LVEF after revascularization.