A Circulatory Support Device for Children with Univentricular Hearts and Failing Fontan Physiology

Key Words: Congenital heart defects, cardiac surgery, Fontan Physiology

A multitude of congenital heart defects result in the need for complex pediatric cardiac surgery. Pediatric patients with single ventricle heart defects undergo multiple surgeries terminating with the Fontan procedure where a cavopulmonary shunt is placed between the inferior vena cava and the pulmonary artery, resulting in passive venous return to the pulmonary system and the left atrium. The functioning ventricle pumps systemically. While this surgery has dramatically improved survival rates for these patients, the passive venous pulmonary return can lead to venous hypertension and low pulmonary flow. This failing Fontan physiology is associated with significant increases in morbidity and mortality in children. The current landscape for mechanical circulatory support devices is unsuitable for this application as left ventricular assist devices are designed for the higher pressures and larger sizes of the adult systemic circulation. Thus, there is a clear unmet need and a feasible opportunity for innovation in this space. We have previously used robotic elements made from compliant materials to assist the adult failing heart with an extracardiac heart sleeve. Here, we propose to leverage this technology to aid venous return in children with failing Fontan physiology. First, we will develop a mock circulatory flow loop that can replicate Fontan dynamic pressures and flows in the lab. Next, we will develop an implantable soft robotic device to actively move venous blood to the lungs and reduce venous pressures with sequentially actuated pneumatic artificial muscles. We will characterize device performance in our flow loop with two metrics – the ability to (i) increase pulmonary blood flow and (ii) reduce elevated venous pressures. Testing multiple iterations of the device design will inform potential feasibility for translation. If successful, this foundational work will enable us to move forward to preclinical implantation with our surgical collaborators, and ultimately to pediatric patients.