Outcomes of children implanted with ventricular assist devices in the United States: First analysis of the Pediatric Interagency Registry for Mechanical Circulatory Support (PediMACS)

Background: Use of mechanical circulatory support in children has increased as more options have become available. A national account of the use of mechanical support in children and adolescents is essential to understanding outcomes, refining patient selection and improving quality of care.

Methods: The Pediatric Interagency Registry for Mechanical Circulatory Support (PediMACS) is a National Heart, Lung, and Blood Institute-supported nationwide registry for temporary and durable ventricular assist device (VAD) use in patients <19 years of age. Between the launch in September 2012 and June 2015, 37 hospitals in the USA have enrolled patients. This first report of data from PediMACS analyzed pre-implant patient characteristics, survival using competing outcomes, and adverse events.

Results: Two hundred pediatric patients underwent 222 durable VAD implants. Patients' characteristics and outcomes of children supported with a temporary device (n = 41) were not analyzed in this report. The etiology of heart disease included 146 (73%) patients with cardiomyopathy and 35 (18%) with congenital heart disease. Thirty patients (15%) transitioned from extracorporeal membrane oxygenation (ECMO) and 76 (38%) had previous cardiac surgery. Most patients were Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) Level 1 (27%) or Level 2 (56%) at implant, with 13% at Level 3. Of the 200 patients supported with a durable device, 91 (46%) were supported with a pulsatile-flow device and 109 (55%) with a continuous-flow (CF) device. Patient age at first implant included 30 patients (15%) <1 year of age, 37 (19%) 1 to 5 years, 32 (16%) 6 to 10 years and 101 (51%) 10 to 18 years. Patients were supported with left ventricular assist device alone in 161 (81%), biventricular ventricular assist device in 29 (15%), right ventricular assist device in 4 (2.0%) and total artificial heart in 6 (3%), together comprising 783 months of follow-up. The 200 patients receiving primary durable devices had an actuarial survival of 81% at 6 months. Competing risk analysis at 6 months revealed that 58% of patients had been transplanted, 28% were alive on support, 14% had died and 0.6% recovered. In the overall cohort, there were 28 deaths. Reported serious adverse events included infection (n = 78), bleeding (n = 68), device malfunction (n = 79) and neurologic dysfunction (n = 52).

Conclusions: PediMACS constitutes the largest single data repository with detailed information of pediatric patients implanted with VADs. The first PediMACS report reveals favorable outcomes despite the varying patient characteristics and pump types. However, the rate of adverse events remains high. With further data collection, analysis of patient risk factors critical to improving outcomes will be possible.