Introduction

The population of pediatric patients suffering from medically resistant heart failure is continuously increasing. While the number of patients transplanted for dilated cardiomyopathy has remained relatively constant, the number of patients with congenital heart disease being listed for transplant has increased significantly over the past 2 decades.[1],[2] This growth has been fueled by advancements in cardiac surgical techniques and improvements in perioperative care, which have improved the early survival for children with congenital heart disease, however, these patients remain at risk for heart failure over the medium to long term. The last 15 years have also seen a concurrent revolution in the field of pediatric mechanical circulatory support.[3],[4],[5] In the late 1990s until 2004, mechanical circulatory support (MCS) for end stage heart failure was limited to extracorporeal membrane oxygenation (ECMO) with the occasional patient supported by short term centrifugal pump ventricular assist devices (VAD) or an adult VAD (for larger-sized adolescents)[5],[6]. The development of the Berlin Heart EXCOR and the current generation of smaller, implantable, continuous-flow VADs have dramatically altered the field.[7],[8],[9] Approximately, 40% of pediatric patients are bridged to cardiac transplantation with VADs in the current era.[9],[10] Despite the greater number of complex patients, VAD support has led to an approximately 50% increase in waitlist survival, and a significant and consistent increase in the number of pediatric heart transplants being performed each year.[11] The most recent Scientific Registry of Transplant Recipients (SRTR) annual report has shown the number of pediatric heart transplants performed in the United States of America has increased from 321 in 2006 to 473 in 2018.[2]

While there have been significant gains in the field, progress has been hampered by a number of factors. Center experience remains a significant predictor of patient outcomes and the number of pediatric centers supporting more than 5 patients per years is relatively small.[12],[13] The pediatric population requiring VAD support is also quite heterogeneous in size, diagnosis and anatomy. This further complicates the challenges inherent to small patient volumes as the number of devices and device configurations currently in use is increasing.[14],[15] Thus, while there has been rapid progress in the field over the last decade, there is a critical need for a wider variety of MCS options for children of all ages and diagnoses, especially infants. Also, while the number of pediatric hospitals implanting VADs continues to increase, establishing best practices and implementing these protocols has been a challenge given limited individual/institutional experience. The Advanced Cardiac Therapies Improving Outcomes Network (ACTION) is a 46 center (as of 7/2020) learning network that was established with the goal of addressing many of these challenges and improving outcomes within the field of pediatric heart failure through data sharing, improving education and establishing best practices.

This chapter describes the basics of MCS support in children and adolescents and highlights the current state of the field in children.