Second annual Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) report: Pre-implant characteristics and outcomes

Background: Expanded use of pediatric ventricular assist devices (VADs) has decreased mortality in children awaiting heart transplantation. Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs), a National Heart, Lung, and Blood Institute-sponsored North American database, provides a platform to understand this emerging population.

Methods: Between September 2012 and September 2016, patients aged younger than 19 years who underwent VAD implantation were enrolled in Pedimacs. FDA approved durable devices as well as temporary support devices were included. The second annual report updates the current Pedimacs data. Patients implanted with temporary devices are included in Pedimacs and this analysis includes this group of paracorporeal continuous flow VADs.

Results: Over the 4 years, 42 hospitals implanted 432 devices in 364 patients less than 19 yrs of age. Diagnoses included cardiomyopathy in 223 (61%), myocarditis in 41 (11%), and congenital heart disease in 77 (21%), of which 48 had single-ventricle physiology. At implant, 87% were at Intermacs patient profile 1 or 2. The age distribution of children (59% male) supported on VAD included 69 (19%) aged younger than 1 year, 66 (18%) aged 1 to 6 years, 56 (15%) aged 6 to 10 years, and 173 (48%) aged 11 to 19 years. Median follow-up was 2.2 months (range, 1 day to 41.5 months). Median (interquartile) age at implant was 1.7 (0.3-10.0) years for paracorporeal continuous-flow pumps (n = 60), 1.7 (0.4-5.3) years for paracorporeal pulsatile pumps (n = 105), and 15.0 (11.3-16.9) years for implantable continuous-flow pumps (n = 174). Support strategies included LVAD in 293 (80%), biventricular device in 55 (15%), and total artificial heart in 8 (2%). Nearly 50% of patients underwent transplantation within 6 months, with overall mortality of 19%. Adverse event burden continues to be high.

Conclusions: Pedimacs constitutes the largest longitudinal pediatric VAD registry. Preimplant data across centers will be helpful at creating shared protocols with which to improve outcomes. Adverse events continue to be the major challenge, especially among the young critically ill children with complex congenital disease.