Establishment of a risk prediction model for thrombotic events in Chinese patients with hypertrophic cardiomyopathy postprint

Abstract: Background: Thromboembolism (TE) events are known to occur as significant complications of hypertrophic cardiomyopathy (HCM). It’s essential to estimate the risk of TE in patiens with HCM. There are two risk prediction models developed by foreign researchers, such as: HCM Risk-CVA and French HCM score, while, current studies have found that the clinincal prediction value of HCM Risk-CVA in HCM patients is limited in the Chinese population. Objective: The primary aim of this study was to derive and validate a model for estimating the risk of TE in Chinese patients with HCM.Methods: The study retrospectively analyzed 513 HCM patients admitted to West China Hospital of Sichuan University. We established a risk assessment tool based on the Cox regression model, and internal validation was performed with the bootstrapping.Results: During a median follow-up of 4.2 years, 42 patients reached the TE endpoint. The variables of the final model included prior TE events, atrial fibrillation, age and left ventricular ejection fraction. According to the regression coefficient of each variable, we constructed SAAE score (S = prior Stroke and other TE, A = Atrial fibrillation, A = Age, E = left ventricular Ejection fraction). Internal validation suggested that SAAE score could discriminate TE in the overall study population. Overall, Harrell's c-index was 0.773（95% CI：0.688-0.858）, and the calibration slope was 1.006. For the overall study population, SAAE score also had good ability to discriminate and calibrate TE at 1, 3 and 5 years. In addition, SAAE score had good discrimination for TE in patients with/without atrial fibrillation. Overall, Harrell's C indexes were 0.669 (95% CI: 0.548-0.791) and 0.647 (95% CI: 0.498-0.795), respectively. In the two groups of HCM patients, SAAE score also had good ability to discriminate and calibrate TE at 1, 3 and 5 years. For the three groups (whole study population, patients with/without atrial fibrillation), the risk stratification based on SAAE score could discriminate TE excellently.Conclusions: We constructed a risk scoring tool, namely SAAE score, for TE in Chinese HCM patients. The constructed risk scoring tool could effectively stratify the risk of TE in Chinese HCM patients.