title: Independent Assessment of the European Society of Cardiology Sudden Death Risk Model for Hypertrophic Cardiomyopathy.
abstract: Risk stratification for sudden death (SD) is an essential component of hypertrophic cardiomyopathy (HC) management, given the proven effectiveness of implantable cardioverter-defibrillators (ICD) for preventing SD. Although highly effective in identifying high-risk patients, current stratification algorithms remain incomplete and novel strategies are encouraged. In this regard, reliability of the statistical model to predict SD risk in HC, as recommended by the recent European Society of Cardiology (ESC) guidelines, was retrospectively tested in an independent cohort of 1,629 consecutive patients with HC aged ≥16 years. Of the 1,629 patients, 35 incurred SD events, but only 4 of these (11%) had high predictive risk scores >6%/5 years consistent with an ICD recommendation, and most (60%; n = 21) had scores <4%/5 years that would not justify ICDs. Of 46 high-risk patients with appropriate ICD interventions for ventricular fibrillation/tachycardia, 27 (59%) had low SD risk scores of <4%/5 years, regarded by ESC as insufficient to recommend ICDs, and only 12 (26%) had scores >6%/5 years, considered an ICD indication; 11 of these 12 had already met conventional criteria warranting implantation with 2 to 3 risk markers. Of 414 patients with ICDs but without appropriate interventions, 258 (62%) had low risk scores (<4%/5 years) that would argue against implant. In conclusion, primary risk stratification using the ESC prognostic score applied retrospectively to a large independent HC cohort proved unreliable for prediction of future SD events. Most patients with HC with SD or appropriate ICD interventions were misclassified with low risk scores and therefore would have remained unprotected from arrhythmic SD without ICDs.
authors.affiliation: Hypertrophic Cardiomyopathy Center, Minneapolis Heart Institute Foundation, Minneapolis, Minnesota. Electronic address: hcm.maron@mhif.org.
authors.forename: Barry J
authors.initials: BJ
authors.lastname: Maron
authors.affiliation: Hypertrophic Cardiomyopathy Center, Minneapolis Heart Institute Foundation, Minneapolis, Minnesota.
authors.forename: Susan A
authors.initials: SA
authors.lastname: Casey
authors.affiliation: Division of Cardiology, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Raymond H
authors.initials: RH
authors.lastname: Chan
authors.affiliation: Hypertrophic Cardiomyopathy Center, Minneapolis Heart Institute Foundation, Minneapolis, Minnesota.
authors.forename: Ross F
authors.initials: RF
authors.lastname: Garberich
authors.affiliation: Division of Cardiology, Hypertrophic Cardiomyopathy Center, Tufts Medical Center, Boston, Massachusetts.
authors.forename: Ethan J
authors.initials: EJ
authors.lastname: Rowin
authors.affiliation: Division of Cardiology, Hypertrophic Cardiomyopathy Center, Tufts Medical Center, Boston, Massachusetts.
authors.forename: Martin S
authors.initials: MS
authors.lastname: Maron
mesh_terms: D000328:Adult; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000150:complications / Q000401:mortality / Q000628:therapy; D002309:Cardiology; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000401:mortality* / Q000628:therapy; D016757:Death, Sudden, Cardiac / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D017147:Defibrillators, Implantable; D005060:Europe / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D012955:Societies, Medical; D015996:Survival Rate / Q000639:trends; D013997:Time Factors