Abstract 17726: Nonischemic Cardiomyopathy in Patients With Coronary Artery Disease

Introduction: Randomized trials in obstructive coronary artery disease (CAD) have largely shown no prognostic benefit from revascularization. While there are several potential reasons for the lack of benefit from coronary revascularization, an underexplored possibility is the presence of coexisting nonischemic myocardial pathology.

Aim: We aimed to investigate the prevalence and prognostic significance of nonischemic cardiomyopathy (NICM) in CAD.

Methods: We studied a large cohort of consecutive patients with obstructive CAD on coronary angiography who had cardiovascular magnetic resonance imaging (CMR) from 2004 to 2020 for clinical indications. CMRs were analyzed for this study for the presence and type of cardiomyopathy. Patients with normal left ventricular ejection fraction and no late gadolinium enhancement (LGE) were classified as having no cardiomyopathy. Ischemic cardiomyopathy (ICM) was defined by ischemic LGE or extensive hibernating myocardium in the absence of LGE. NICM was defined by nonischemic LGE, absence of LGE without hibernating myocardium, or morphological abnormalities of NICM such as left ventricular hypertrophy. The study endpoint was a composite of all-cause death or hospitalization for heart failure.

Results: Among 3,027 patients (mean age 65 years, 24% women), 18% had no cardiomyopathy, 65% had only ICM, and 17% had NICM. Of those with NICM, 38% also had ICM (dual cardiomyopathy). At a median follow-up of 4.7 years, 1,112 patients experienced the study endpoint. On Kaplan-Meier analysis, patients with NICM had a higher cumulative incidence of the study endpoint compared with no cardiomyopathy and ICM (log-rank P<0.001 for both comparisons). On multivariable regression analyses, NICM was associated with a greater risk for the study endpoint-hazard ratio (HR) 1.77; 95% confidence interval (CI) 1.43-2.19; P<0.001 compared with no cardiomyopathy and HR 1.27; 95% CI 1.09-1.47; P=0.003 compared with ICM, after adjustment for potential confounders.

Conclusions: NICM was identified in 1 in 6 patients with CAD and was associated with worse long-term outcomes compared with no cardiomyopathy and ICM. In patients with obstructive CAD, coexisting NICM may contribute to the lack of prognostic benefit from revascularization.