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 grafting (CABG) for patients with ischemic left ventricular dysfunction (ILVD) remains controversial. This 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 fluorine-18 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 end point was all-cause death. The secondary end point was a composite of cardiovascular death, cardiovascular hospitalization, heart transplantation, revascularization, insertion of an implantable cardioverter-defibrillator, or nonfatal stroke. Cox models calculated hazard ratios (HRs) and CIs for CABG vs medical therapy alone for subgroups with different levels of hibernation and scars.

Results

During a median follow-up of 71.5 months in 507 patients, 98 patients reached the primary end point and 194 reached the secondary end point. After adjustment, CABG was associated with lower risks of all-cause mortality (HR, 0.249; 95% CI, 0.154-0.428; P<.001) and lower incidences of secondary outcomes (HR, 0.457; 95% CI, 0.318-0.658; P<.001) compared with medical treatment alone in the population. Across all 4 subgroups classified by the optimal cutoff 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 appear not to influence the effects of CABG in patients with ILVD.