Search

Background: The HeartWare ventricular assist device (HVAD) was discontinued in July 2021. The study aims to describe the impact the discontinuation the HVAD had on pediatric ventricular assist device (VAD) utilization and outcomes. Methods: The Advanced Cardiac Therapies Improving Outcomes Network (ACTION) registry was queried for type of VAD utilization and outcomes/adverse event rates in patients with a body surface area of 0.7 to 1.4 m2. Results were compared from before and after July 2021. All patients in the registry implanted with an HVAD were reported to determine overall outcomes of these patients and define who remains on the device. Results: The HeartMate 3 (HM3) primarily replaced the HVAD in pediatric patients increasing from 29 of 258 (11%) of implants before July 2021 to 31 of 109 (29%) of implants after. A small increase in the use of the Berlin Heart EXCOR (40 of 258, 16% before to 20 of 109, 18% after) and paracorporeal continuous flow devices (116 of 258, 45% before to 58 of 109, 53% after) was also observed. The rate of ischemic stroke increased in the overall population and a decrease in bleeding complications in the EXCOR group was observed. Of the 187 pediatric patients implanted with an HVAD in the registry, 7 patients remain supported, 1 patient transitioned from the HVAD to an HM3, and 6 patients were lost to follow-up. Conclusions: The HM3 has been the primary replacement for the HVAD in the medium-sized pediatric population. The rate of ischemic stroke was higher after July 2021.

Summary: Pathogenic variants in the DES gene clinically manifest as progressive skeletal muscle weakness, cardiomyopathy with associated severe arrhythmias, and respiratory insufficiency, and are collectively known as desminopathies. While most DES pathogenic variants act via a dominant mechanism, recessively acting variants have also been reported. Currently, there are no effective therapeutic interventions for desminopathies of any type. Here, we report an affected individual with rapidly progressive dilated cardiomyopathy, requiring heart transplantation at age 13 years, in the setting of childhood-onset skeletal muscle weakness. We identified biallelic DES variants (c.640-13 T>A and c.1288+1 G>A) and show aberrant DES gene splicing in the affected individual’s muscle. Through the generation of an inducible lentiviral system, we transdifferentiated fibroblast cultures derived from the affected individual into myoblasts and validated this system using RNA sequencing. We tested rationally designed, custom antisense oligonucleotides to screen for splice correction in these transdifferentiated cells and a functional minigene splicing assay. However, rather than correctly redirecting splicing, we found them to induce undesired exon skipping. Our results indicate that, while an individual precision-based molecular therapeutic approach to splice-altering pathogenic variants is promising, careful preclinical testing is imperative for each novel variant to test the feasibility of this type of approach for translation.