Mp-453089-11 differences in utilization of primary prevention implantable cardioverter defibrillators in arrhythmogenic right ventricular cardiomyopathy across north america and europe

Implantable cardioverter-defibrillators (ICDs) are critical for preventing sudden cardiac death (SCD) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC), but differences in their utilization across North America and Europe are unknown. To identify cross-national differences in both utilization of primary prevention ICDs and survival free from ventricular arrhythmia (VA) in patients with ARVC. This was a retrospective analysis of ARVC patients without prior sustained VA enrolled in clinical registries in 11 countries throughout Europe and North America. Patients were classified according to whether they received treatment in North America or Europe. They were further stratified by their calculated 5-year VA risk (low: <10%/5y, intermediate: 10-25%/5y, high: >25%/5y) using the ARVC risk calculator (ARVCrisk.com). Differences in rates of ICD implantation and VA-free survival were assessed using the Kaplan-Meier method and log-rank testing. Differences in VA-free survival were also assessed in the subset of patients without ICD. 1,098 patients were followed for a median of 5.1 years, during which time 554 (50.5%) received a primary prevention ICD. Patients treated in Europe were more likely to be probands (61.5% vs 52.0%, p=0.002) and were diagnosed at older ages (42 vs. 32 years, p<0.001). Baseline 5-year VA risk was similar (19.5% vs 19.4, p-value 0.71). North Americans were twice as likely to receive primary prevention ICDs (13.6%/year vs. 6.4%/year, p<0.001) and had shorter times from diagnosis to ICD implantation (83 days vs. 243 days, p<0.001). Overall, 285 patients (25.9%) experienced a first sustained VA event. Rates of VA were higher in North Americans compared to Europeans (6.0%/year versus 4.2%/year, p<0.001); this increase was driven primarily by higher rates of appropriate ICD therapy in North Americans (70.7% vs 59.3% of events). In sub-analysis of patients without ICD, North Americans had higher rates of VA events than Europeans (3.4%/year vs 2.4%/year, p=0.01). When stratified by baseline VA risk, North Americans received significantly more ICDs at all risk strata despite similar rates of VA events in low and intermediate risk patients (Figure). North American ARVC patients were significantly more likely to receive primary prevention ICDs across all risk strata than their European counterparts. However, a lower rate of primary prevention ICD implantation in Europe was not associated with a higher rate of adverse VA outcomes.