Implantation of HeartWare Left Ventricular Assist Device in Pediatric Population

Abstract

The new-generation continuous-flow left ventricular assist devices (VAD) have dramatically improved clinical outcomes of adult patients with end-stage heart failure in the current era. 1 In the adult population, multiple devices are available as a long-term bridge to transplantation 2 and as destination therapy 1 with low device-related morbidity and mortality. On the contrary, long-term mechanical circulatory support options in the pediatric population have been extremely limited. Pediatric patients with end-stage heart failure have traditionally been supported with extracorporeal membrane oxygenation with dismal success rate for bridge to transplantation owing to extracorporeal membrane oxygenation–related complications. 3 Recent clinical application of the EXCOR pediatric assist device (Berlin Heart), a paracorporeal pulsatile-flow VAD, has substantially improved the survival of the patients who were bridged to transplantation with VAD. 4 Nonetheless, approximately one-third of the patients who are supported with the Berlin Heart have embolic stroke and other major complications. 4 Adult-sized VADs have been used in adolescents and some selected patients with a high rate of bridge to transplantation 5 ; however, the mismatch between device and body sizes precludes routine use of adult-sized VADs in the pediatric population. The HeartWare ventricular assist system (HVAD) (HeartWare, Framingham, MA) is a new-generation, small, centrifugal, continuous-flow pump. This device is designed to be implanted directly into the left ventricle and positioned within the pericardial space without requiring a subdiaphragmatic pocket. The initial clinical trial using HVAD showed 90.7% success rate (transplanted or alive) with reasonable incidence of stroke (12%) in patients who were supported with HVAD, which was equivalent to that of the commercially available devices. 6 HVAD is particularly attractive for the pediatric population because of the small pump size and integrated short inflow cannula, which allows complete intrapericardial implantation. In Canada, HVAD has been implanted since 2010, and the first HVAD implantation was performed in 2011 in The Hospital for Sick Children. Herein, the surgical principles and techniques of HVAD implantation in the pediatric population are discussed.