[Incremental value of CMR for the 2025 appropriate use criteria of ICD implantation in sudden cardiac death risk stratification of dilated cardiomyopathy].

Abstract

Objective: To evaluate the predictive value of the 2025 appropriate use criteria (AUV) for implantable cardioverter defibrillators (ICD) jointly issued by the American College of Cardiology/American Heart Association and other societies, for sudden cardiac death (SCD) in patients with dilated cardiomyopathy (DCM), and to explore the incremental value of cardiac magnetic resonance (CMR) tissue characterization in SCD risk stratification. Methods: This was a single-center, retrospective study that consecutively enrolled DCM patients who underwent CMR with late gadolinium enhancement (LGE) and T1 mapping at Fuwai Hospital, Chinese Academy of Medical Sciences from February 2012 to September 2021. According to the 2025 ICD appropriate use criteria and LGE extent, patients were divided into three groups: AUC-appropriate with LGE<7.2% (AUC-A+LGE<7.2%) group, AUC-appropriate with LGE≥7.2% (AUC-A+LGE≥7.2%) group, and AUC-maybe appropriate (AUC-M) group. Baseline data and CMR parameters were collected, and all patients were followed up. Predictors of the SCD composite endpoint were identified using Cox proportional hazards regression, and the clinical efficacy of LGE and extracellular volume fraction (ECV<31.8% or ≥31.8%) for SCD risk stratification was assessed using Kaplan-Meier survival analysis. Results: A total of 741 DCM patients were enrolled, aged (47.0±14.3) years, with 581 (78.4%) males. There were 447 patients in the AUC-A+LGE<7.2% group, 162 in the AUC-A+LGE≥7.2% group, and 132 in the AUC-M group. Over a follow-up of 53.4 (32.9, 74.8) months, the SCD composite endpoint occurred in 78 patients (10.5%). Multivariable Cox regression analysis identified left atrial volume index (HR=1.005, 95%CI 1.001-1.009, P=0.015), right ventricular ejection fraction (HR=0.976, 95%CI 0.963-0.990, P<0.001), LGE≥7.2% (HR=4.308, 95%CI 2.633-7.050, P<0.001), and ECV≥31.8% (HR=2.719, 95%CI 1.515-4.878, P<0.001) were predictors of the SCD composite endpoint. Kaplan-Meier analysis showed no significant difference in SCD risk between the AUC-A+LGE<7.2% group and AUC-M group (log-rank P=0.269). Further stratification revealed that patients with ECV<31.8% in the AUC-A+LGE<7.2% subgroup had an extremely low annual SCD event rate of 0.6%, representing a truly low-risk population accounting for 35.8% (265/741) of the total cohort. In contrast, the annual SCD event rate in the AUC-A+LGE≥7.2% group was as high as 5.5%. Conclusions: CMR myocardial tissue characterization parameters (LGE and ECV) provide significant incremental prognostic value to the 2025 ICD appropriate use criteria, enabling precise re-stratification of SCD risk in DCM patients and facilitating optimized clinical decision-making for primary prevention with ICD implantation.