PEDS12: Use of Impella 5.5 in the Pediatric Population – Safety and Outcomes

Abstract

Background: Transvalvular micro-axial flow pumps for mechanical circulatory support have continued to advance, with the latest devices providing up to 5.5L/min of flow. These devices have been successfully utilized in the adult population, however safety and efficacy data in the pediatric patient is limited. Here, we present our institutional experience with Impella 5.5 placement in pediatric patients. Methods: Five pediatric patients underwent right axillary artery graft placement and attempted placement of the Impella 5.5 device between August 2020 and January 2023 at our institution. Most patients received pre-operative imaging to evaluate axillary artery anatomy, and all undergo post-operative monitoring for hemolysis and device positioning. Results: Five pediatric patients received Impella 5.5 placement: three male and two female patients, ages 13.2, 13.7, 13.8, 16.8, and 16.9 years (Table). Indications for device implantation were heart failure secondary to myocarditis (2), allograft rejection of prior orthotopic heart transplant, idiopathic dilated cardiomyopathy, and heart failure after transposition of the great arteries repair. Impella 5.5 placement was unsuccessful in a 13.8-year-old female patient due to prohibitively acute right subclavian anatomy, and VA-ECMO cannulation was performed instead via the axillary graft. In the four patients with successful Impella 5.5 placements, median duration of support was 13.5 days (range 7-42 days). One patient experienced cardiac arrest secondary to coagulation-associated device failure, requiring temporary left ventricular assist device implantation (Figure). Three patients were bridged to transplant, two of whom received transplant directly from Impella 5.5, while one received transplant after HeartMate III. The final patient had a HeartMate III placed on Impella day 42 and is currently awaiting transplant. Conclusion: The Impella 5.5 is a minimally invasive mechanical circulatory support device which can be used to bridge pediatric patients to cardiac transplantation. Although exact size cutoff and anatomy are still being determined, our experience gives a framework for which smaller patients are still appropriate for device placement. Careful patient selection and post-placement monitoring are required to achieve optimal outcomes as a bridge to recovery, durable device, or transplant.Figure 1. Operative image demonstrating clot at Impella 5.5 outflow tract associated with cardiac arrest and device failure.