Prognostic utility of coronary microvascular dysfunction and c-reactive protein-triglyceride-glucose index for risk stratification in non-ischemic dilated cardiomyopathy

The prognostic value of coronary microvascular dysfunction, assessed by angiography-derived index of microcirculatory resistance (angio-IMR), and systemic metabolic-inflammatory dysregulation, evaluated via the C-reactive protein-triglyceride-glucose index (CTI), remains uncharacterized in patients with dilated cardiomyopathy (DCM). In this multicenter retrospective study of 343 DCM patients, angio-IMR and CTI were calculated. The CTI was calculated by \(\:{0.412} × {ln}{({CRP}[{mg}/{L}])+}{ln}{({TG}[{mg}/{dL}] {×} {FPG}[{mg}/{dL}])/{2}}\) . The primary outcome was major adverse cardiovascular events (MACE), a composite of cardiac death or heart failure readmission. Over a median 4.04-year follow-up, 124 patients (36.2%) experienced MACE. Multivariable analysis identified both left anterior descending artery (LAD) angio-IMR [adjusted hazard ratio (HR) 1.04, 95% confidence interval (CI) 1.01–1.08, p = 0.020] and CTI (adjusted HR 2.08, 95% CI 1.32–3.28, p = 0.002) as independent predictors. Patients with high LAD angio-IMR had significantly higher MACE incidence than those with low values (58.71% vs. 34.71%, p < 0.001). Those with both high LAD angio-IMR and high CTI experienced the highest event rates, and only this subgroup remained an independent predictor of MACE after adjustment (adjusted HR 5.35, 95% CI 2.65–10.81, p < 0.001). A model combining angio-IMR and CTI significantly improved risk discrimination over conventional clinical predictors (area under the curve 0.783 vs. 0.708, p = 0.018). Elevated LAD angio-IMR and CTI are independent prognostic indicators in DCM. Their combined assessment facilitates the identification of the highest-risk patient subsets and provides substantial incremental predictive value for MACE beyond conventional clinical risk models. The name of the registry: ClinicalTrials.gov. The trial registration number: NCT07293338. The date that we registered our trial in December 17, 2025.