Association of revascularization with mortality in ischemic left ventricular dysfunction

Abstract

Abstract Background Revascularization in patients with left ventricular (LV) dysfunction has been a subject of ongoing uncertainty and conflicting results. This is further complicated by factors including viability, severity of LV dysfunction, and method of revascularization using percutaneous coronary intervention (PCI) versus coronary-artery bypass grafting (CABG). The purpose of this meta-analysis is to evaluate the association of coronary revascularization with mortality in patients with ischemic LV dysfunction. Methods A literature search was conducted for studies reporting on all-cause mortality after revascularization with PCI or CABG compared to optimal medical therapy (OMT) in patients with ischemic LV dysfunction. The search included the following databases: Ovid MEDLINE, EMBASE, Web of Science, and Google Scholar. The search was not restricted to time or publication status. Results A total of 21 studies with 6062 participants (2838 revascularized, 3224 on OMT) met inclusion criteria. Mean follow-up was 37 months (11-68 months), mean LV ejection fraction (EF) was 29%, mean age was 61, 85% of patients were male. Revascularization was significantly associated with lower all-cause mortality compared to patients on OMT (OR 0.57, 95% CI 0.46-0.71; p<0.01). The association was statistically significant regardless of severity of LV dysfunction or method of revascularization. Heterogeneity between subgroups was low and test for subgroup difference was not statistically significant by EF cutoff of 35% or by revascularization method (p=0.43, I2=0%; p=0.12, I2=59.7%). Subgroup analysis by viability demonstrated that revascularization was significantly associated with lower all-cause mortality compared to OMT for patients with viability and mixed cohorts with or without viability, but not patients without viability (OR 0.47, 95% CI 0.33-0.66; p<0.01; OR 0.57, 95% CI 0.38-0.84; p<0.01; OR 0.73, 95% CI 0.51-1.02; p=0.07). The effect size was larger in the subgroup with viable myocardium compared to mixed patients with viable or non-viable myocardium (Z=4.33 vs 2.79). Conclusions Revascularization in patients with ischemic LV dysfunction is associated with lower risk of all-cause mortality independent of severity of LV dysfunction or method of revascularization. Revascularization is not associated with lower risk of all-cause mortality in patients without evidence of viable myocardium.