Ventricular Assist Device Use in Pediatric Restrictive and Hypertrophic Cardiomyopathy: An ACTION Registry Analysis

The use of ventricular assist devices (VADs) in children with restrictive (RCM) and hypertrophic cardiomyopathy (HCM) remains rare. We describe the outcomes of patients with RCM and HCM supported by VAD in the Advanced Cardiac Therapies Improving Outcomes Network (ACTION) registry from March 2012 to December 2024. Thirty-four patients were identified: 20 left-sided VAD (LVAD), 13 biventricular VAD (BiVAD), and 1 total artificial heart (TAH). Median age at implant was 2.5 years (0.3-17.5), weight was 11.8 kg (4.5-81.8), and body surface area (BSA) was 0.54 m² (0.26-2.01). Diagnoses included RCM in 25 (73.5%) patients and HCM in 9 (26.5%). Illness severity at implant was high with 38.2% Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profile 1, 41.2% on extracorporeal membrane oxygenation (ECMO), 52.9% on ventilator support, 88.2% treated with greater than or equal to 1 inotrope, and 52.9% supported with TPN. Four patients (11.8%) died on device, 25 (73.5%) were transplanted, 4 (11.8%) were alive on device, and 1 (2.9%) was transferred to another center. Patients who died all had HCM diagnosis, required BiVAD support, and experienced adverse events. The cause of death was inadequate support (1), infection (2), and multi-organ failure (1). Ventricular assist device support is a reasonable strategy for select RCM and HCM patients, although outcomes in HCM are less favorable.