Abstract 15961: Multicenter Prospective Prevention of Sudden Death in High Risk Patients Utilizing Enhanced ACC/AHA Risk Model

Abstract

Introduction: Strategies for reliable selection of high-risk hypertrophic cardiomyopathy (HCM) patients for prevention of sudden cardiac death (SCD) with implantable cardioverter-defibrillators (ICDs) continue to be debated. Objective: Assess the sensitivity of sudden death risk strategies in predicting SCD events (appropriate ICD shocks, sudden death or out of hospital cardiac arrest) among a large multicenter cohort of high-risk HCM patients. Methods: Observational longitudinal study from 6-HCM centers in North America and Europe to determine outcomes in consecutive HCM patients considered high risk for sudden death based on an enhanced ACC/AHA (U.S./Canada) guidelines-based risk factor algorithm with primary prevention ICD placement. ESC risk score was retrospectively calculated in this cohort and compared to ACC/AHA risk factor method for predicting SCD events. Results: Of 1185 patients with primary prevention ICDs implanted based on ≥ 1 major risk marker, 162 (14%) experienced device therapy terminating VT/VF episodes at 49 ± 18 years of age and 4.6 ± 4.2 years after device implant. Within the 6 HCM centers, only 28 other patients not implanted with ICD died suddenly or had resuscitated cardiac arrests, including 19 (68%) with risk-markers who declined ICDs. Of these 190 high risk patients with SCD or SCD events, 67 (35%) had ESC risk-scores scores ≥6%/5-years, considered sufficient to recommend a prophylactic ICD, while 83 (44%) had low risk scores (<4%/5-years) that likely would have excluded an ICD recommendation. Compared to enhanced ACC/AHA risk factors, the ESC risk-score was less sensitive than ACC/AHA (35% vs. 95%, p<0.01), consistent with identifying fewer high-risk patients with events. Conclusion: In this large multicenter study of high-risk HCM patients, an enhanced ACC/AHA risk factor strategy was superior to the ESC risk score in identifying patients at greatest risk for SCD events.