An International External Validation Study of the 2014 European Society of Cardiology Guideline on Sudden Cardiac Death Prevention in Hypertrophic Cardiomyopathy (Evidence from HCM)
Background—Identification of people with hypertrophic cardiomyopathy (HCM) who are at risk of sudden cardiac death (SCD) and require prophylactic implantable cardioverter defibrillator (ICD) is challenging. In 2014, the European Society of Cardiology (ESC) proposed a new risk stratification method based on a risk prediction model (HCM Risk-SCD) which estimates the 5-year risk of SCD. The aim was to externally validate the 2014 ESC recommendations in a geographically diverse cohort of patients recruited from North America, Europe, The Middle East and Asia.
Methods—This was an observational, retrospective, longitudinal cohort study.
Results—The cohort consisted of 3703 patients. Seventy three (2%) patients reached the SCD end-point within 5 years of follow-up [5-year incidence 2.4% (95% CI 1.9, 3.0)]. The validation study revealed a calibration slope of 1.02 (95% CI 0.93 to 1.12); C-index 0.70 (95% CI 0.68 to 0.72) and D-statistic 1.17 (95% CI 1.05 to 1.29). In a complete case analysis (n= 2147; 44 SCD end-points at 5 years) patients with a predicted 5-year risk of <4% (n=1524; 71%) had an observed 5-year SCD incidence of 1.4% (95% CI 0.8, 2.2); patients with a predicted risk of ≥6% (n=297; 14%) had an observed SCD incidence of 8.9% (95% CI 5.96, 13.1) at 5 years. For every 13 (297/23) ICD implantations in patients with an estimated 5 year SCD risk ≥6%, 1 patient can potentially be saved from SCD.
Conclusions—This study confirms that the HCM Risk-SCD model provides accurate prognostic information which can be used to target ICD therapy in patients at the highest risk of SCD.
- hypertrophic cardiomyopathy
- sudden cardiac death
- ventricular fibrillation
- implanted cardioverter defibrillator
- Received July 9, 2017.
- Revision received October 18, 2017.
- Accepted November 6, 2017.