International External Validation Study of the 2014 European Society of Cardiology Guidelines on Sudden Cardiac Death Prevention in Hypertrophic Cardiomyopathy (EVIDENCE-HCM)

Circulation. 2018 Mar 6;137(10):1015-1023. doi: 10.1161/CIRCULATIONAHA.117.030437. Epub 2017 Nov 30.


Background: Identification of people with hypertrophic cardiomyopathy (HCM) who are at risk of sudden cardiac death (SCD) and require a prophylactic implantable cardioverter defibrillator is challenging. In 2014, the European Society of Cardiology proposed a new risk stratification method based on a risk prediction model (HCM Risk-SCD) that estimates the 5-year risk of SCD. The aim was to externally validate the 2014 European Society of Cardiology recommendations in a geographically diverse cohort of patients recruited from the United States, 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% confidence interval {CI}, 1.9-3.0]). The validation study revealed a calibration slope of 1.02 (95% CI, 0.93-1.12), C-index of 0.70 (95% CI, 0.68-0.72), and D-statistic of 1.17 (95% CI, 1.05-1.29). 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) implantable cardioverter defibrillator 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 that can be used to target implantable cardioverter defibrillator therapy in patients at the highest risk of SCD.

Keywords: cardiomyopathy, hypertrophic; death, sudden, cardiac; defibrillators, implantable; forecasting; risk assessment.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Cardiology*
  • Cardiomyopathy, Hypertrophic / complications
  • Cardiomyopathy, Hypertrophic / diagnosis
  • Cardiomyopathy, Hypertrophic / epidemiology*
  • Cohort Studies
  • Death, Sudden, Cardiac / etiology
  • Death, Sudden, Cardiac / prevention & control*
  • Defibrillators, Implantable / statistics & numerical data
  • Europe / epidemiology
  • Follow-Up Studies
  • Humans
  • Incidence
  • Practice Guidelines as Topic
  • Prognosis
  • Research Design
  • Retrospective Studies
  • Risk
  • Societies, Medical