Impact of myocardial hibernation and scar on benefits from CABG in ischemic left ventricular dysfunction.

Abstract

Background: The significance of evaluating myocardial viability in making decisions regarding coronary artery bypass graft surgery (CABG) for ischemic left ventricular dysfunction (ILVD) patients remains controversial. The study aimed to examine the impact of integrated assessment of hibernating myocardium and scars on the survival benefit associated with CABG in patients with ILVD.

Methods: Consecutive patients with ILVD who underwent ¹⁸F-fluorodeoxyglucose positron emission tomography and cardiac magnetic resonance imaging with late gadolinium enhancement viability testing from January 2015 and April 2018 were retrospectively enrolled. The primary endpoint was all-cause death. The secondary endpoint was a composite of cardiovascular death, cardiovascular hospitalization, heart transplantation, revascularization, implantation of an implantable cardioverter defibrillator, or non-fatal stroke. Cox models calculated hazard ratios (HRs) and confidence intervals (CIs) for CABG versus medical therapy alone for subgroups with different levels of hibernation and scars.

Results: During a median follow-up of 71.5 months of 507 patients, 98 patients reached the primary endpoint and 194 reached the secondary endpoint. After adjustment, CABG was associated with lower risks of all-cause mortality (HR 0.249, 95%CI 0.154-0.428, P<0.001) and lower incidences of secondary outcomes (HR 0.457, 95%CI 0.318-0.658, P<0.001) compared to medical treatment alone in overall population. Across all four subgroups classified by the optimal cut-off value (10% hibernation and 26% scar), CABG was associated with favorable outcomes regardless of the hibernation and scar level.

Conclusions: The extent and severity of hibernating myocardium and scars appears not to impact the effects of CABG in patients with ILVD.