Myocardial viability and prognosis of patients with left ventricular dysfunction according to treatment strategy: a systematic review and a meta-analysis

Introduction Clinical guidelines have historically endorsed myocardial viability testing to guide revascularization decisions, but recent data question its universal utility. Aim To determine whether the presence or absence of myocardial viability (V+, V-, respectively) influences mortality in patients with ischemic cardiomyopathy and left ventricular dysfunction undergoing revascularization (R) or optimal medical treatment (OMT). Methods A comprehensive search of PubMed, Scopus, and Cochrane databases was conducted through August 2023, adhering to PRISMA 2020 guidelines. Eligible studies included patients with mean left ventricular ejection fraction <40%, ischemic cardiomyopathy confirmed by coronary angiography, and viability status assessed via stress echocardiography, MRI, PET, or SPECT. Included studies reported all-cause or cardiovascular mortality with a minimum follow-up of one year. Risk of bias was evaluated with the Rob-2 and Robins-I (for randomized and non-randomized studies, respectively) tools by Cochrane. Patient groups for comparisons were prespecified by combining two covariates, the therapeutic approach (R/OMT) and the viability status (V+/V-), so that the performed comparisons were between any two of the groups: V+/R, V+/OMT, V-/R, and V-/OMT. Random-effects meta-analyses were conducted in all comparisons, using the relevant risk ratios (RR) to synthesize the mean effect size. Heterogeneity was evaluated with I² statistics, and publication bias was assessed using funnel plots and Egger’s tests. Subgroup and sensitivity analyses explored sources of variability. Results A total of 53 studies involving 8675 patients were analyzed, with a mean follow-up of 3.2 years (range: 1–10.4 years). Among patients with documented myocardial viability, treatment with OMT, compared with R, was associated with significantly (p < 0.001) higher risks of all-cause mortality (RR = 1.81, 95% CI: 1.51–2.18) and cardiovascular mortality (RR = 1.77, 95% CI: 1.42–2.21) (Figure 1A–B). In contrast, among patients without viable myocardium, mortality rates did not differ between OMT and R. Furthermore, among patients undergoing R, the absence of myocardial viability was associated (p < 0.001) with higher risks of all-cause mortality (RR = 1.73, 95% CI: 1.40–2.13) and cardiovascular mortality (RR = 1.89, 95% CI: 1.53–2.44) compared with its presence (Figures 2A–B, respectively). Conclusion Although this meta-analysis does not establish that viability testing should guide revascularization decision-making, it highlights the prognostic importance of myocardial viability in patients with ischemic cardiomyopathy and left ventricular dysfunction. Revascularization was associated with improved survival only among patients with viable myocardium. Furthermore, the presence of myocardial viability was associated with improved survival only among patients who received revascularization therapy.Figure 1Figure 2