Abstract 12104: Pediatric Hypertrophic Cardiomyopathy With Left Ventricular Systolic Dysfunction: Insights From the Sarcomeric Human Cardiomyopathy Registry (SHaRe)

Abstract

Introduction: Left ventricular systolic dysfunction (LVSD, LV ejection fraction (LVEF) <50), occurs in ~8% of adults with hypertrophic cardiomyopathy (HCM) and is associated with poor prognosis. However, the incidence and prognosis of LVSD in pediatric patients with HCM (<18 years old) is poorly understood. Methods: Patients in SHaRe with pediatric HCM were included. Time-to-event analyses were performed to estimate 1) cumulative incidence of LVSD in pediatric vs adult HCM (Kaplan Meier), 2) predictors of incident LVSD in pediatric HCM (Cox-proportional hazards) and 3) a composite outcome of all-cause mortality, heart transplant and left ventricular assist device implant in pediatric HCM. Results: In total, 1296 pediatric HCM patients (34% females, median 12.2 years at diagnosis, median 8.3 years follow-up) were included. LVSD occurred in 155 (12%) of patients with 29% (n=45) having LVSD at the first SHaRe visit and 22% (n=34) developing LVSD <18 years old. At 5-year follow-up, the cumulative incidence of LVSD was 9% [8-11%]. Predictors of incident pediatric LVSD included HCM before age 12 (HR 2.0 [1.3-3.0]), female sex (HR 0.49 [0.32-0.77]), P/LP variants in thick filament genes (HR 2.6 [1.1-4.2], multiple P/LP variants (HR 9.1 [CI 2.9-29.1]) and baseline LVEF (HR 0.63 [0.58-0.68], per 5 %-points increase). Pediatric HCM was associated with higher rate of LVSD compared to adult-onset HCM (n=6428, median HCM at age 49 years, median follow-up of 7.1 years), p=0.05 (Figure 1). The composite endpoint occurred in 41% (n= 63/155) of children with HCM and subsequent LVSD. In patients with LVSD, female sex (HR 2.44 [1.41-4.17]) and baseline LVEF <35% (HR 4.0 [2.4-6.9]) were independently associated with the composite outcome. Conclusion: Females were less likely to develop LVSD but more likely to have adverse outcomes once they do. Clinical outcomes are adverse, and greater recognition of and surveillance for LVSD in pediatric HCM are warranted.