High-Sensitivity Cardiac Troponin I for Enhanced Risk Stratification in Primary Prevention for Sudden Cardiac Death in Hypertrophic Cardiomyopathy

BACKGROUND: Risk stratification of sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM) remains challenging. High-sensitivity cardiac troponin I (hs-cTnI) specifically reflects myocardial damage whereas its relationship with SCD risk in HCM is unclear. OBJECTIVE: This study aimed to investigate the prognostic value of hs-cTnI on enhancing SCD risk stratification in HCM. METHODS: This cohort study consecutively enrolled 705 patients with confirmed diagnosis of HCM. The baseline and clinical follow-up data were collected. The primary end point was defined as SCD or SCD-equivalent events including witnessed arrhythmic cardiac arrest and sustained ventricular tachycardia or ventricular fibrillation requiring intervention. RESULTS: The final analysis included 559 patients with a mean age of 53.0 years, 66.2% male, 16.1% with an implantable cardioverter-defibrillator (ICD), and a mean hs-cTnI level of 0.021 ng/mL. The mean follow-up was 862 days, with 51 patients (9.1%) experiencing SCD events. hs-cTnI showed a significant nonlinear association with SCD risk and remained as an independent predictor (adjusted hazard ratio 2.93 95% confidence interval 1.89‒4.54, P < .0001). The optimal threshold value of hs-cTnI for increased risk of SCD was 0.0405 ng/mL. The addition of hs-cTnI to the conventional risk score model significantly improved the predictive performance (C-statistic increased from 0.752 to 0.813; P = .007). Patients with both elevated risk score and hs-cTnI had the worst prognosis (P < .0001). CONCLUSION: hs-cTnI could be an independent predictor of SCD risk for patients with HCM. Integrating hs-cTnI into SCD risk assessment may provide additional indication of ICD implantation for primary prevention.