The Long-term Mortality Predictors of the Hypertrophic Cardiomyopathy Cases with Low Risk of SCD

OBJECTIVE
Hypertrophic cardiomyopathy (HCM) is a widespread hereditary cardiac disorder. The Turkish population may exhibit clinical differences compared to populations in other countries. This study examined the correlation between sudden cardiac death (SCD) score and long-term mortality in low-risk HCM patients, as well as the predictors of long-term mortality. It also sought to investigate the clinical characteristics and outcomes of HCM patients at a tertiary cardiology center.

METHOD
Between 2004 and 2021, 340 HCM patients without implantable cardioverter defibrillators were monitored at a single tertiary cardiology center in Turkey. The study was implemented retrospectively. The HCM Risk-SCD score was employed to integrate demographic and clinical variables with the predicted 5-year risk. The patients with an HCM Risk-SCD <4% were categorized into three equal tertiles, ranging from low to high SCD scores. Subsequently, the tertiles were compared.

RESULTS
Our study identified older age [HR 95% CI, 1.048 (1.018-1.080)], incidence of cerebrovascular accident [HR 95% CI, 3.675 (1.158-11.656)], and elevated neutrophil count [HR 95% CI, 1.450 (1.250-1.681)] as independent risk factors for long-term mortality in the HCM Risk-SCD <4% cohort. The ROC curve revealed that the optimum value of HCM Risk-SCD to predict the long-mortality in overall study cohort was > 1.79, with 55% sensitivity and 55% specificity (area under curve (AUC): 0.60, 95% CI: 0.52–0.69, p<0.001). No statistically significant difference in long-term mortality was identified among the patients in the Kaplan-Meier curve (p: 0.296).

CONCLUSION
Advanced age, cerebrovascular accident, and elevated neutrophil count are independent risk factors for long-term mortality in patients with HCM Risk-SCD <4%. Patients classified as low risk should undergo further assessment utilizing supplementary tools to avert SCD.