Viability testing for guiding revascularization in ischemic cardiomyopathy.

PURPOSE OF REVIEW: Myocardial viability testing has traditionally been used to guide revascularization decisions in ischemic cardiomyopathy on the assumption that identifying dysfunctional but viable myocardium predicts functional recovery and improved survival following revascularization. Recent trials have challenged this assumption, highlighting the need to re-evaluate the clinical role of viability testing in the context of contemporary revascularization strategies and modern guideline-directed medical therapy.

RECENT FINDINGS: The STICH trial and its extended follow-up demonstrated that CABG improves long-term survival independently of viability status and independently of whether ejection fraction improves, challenging the mechanistic assumption of viability-guided revascularization. REVIVED-BCIS2 showed that PCI may not improve survival benefit, even in patients selected with demonstrated viability. A prespecified imaging substudy of REVIVED identified scar burden, rather than the presence of viable myocardium, as the strongest independent predictor of adverse outcomes, reframing the prognostic question from the detection of viable tissue toward the quantification of irreversible myocardial loss.

SUMMARY: Viability should be reconceptualized as a continuous spectrum rather than a binary construct. Scar quantification, particularly through late gadolinium enhancement cardiac magnetic resonance (CMR), may offer greater prognostic utility than viability detection alone. A prospective randomized trial integrating contemporary imaging with modern guideline-directed medical therapy is needed to resolve the clinical role of viability-guided revascularization.