PROJECT SUMMARY Mechanical circulatory support (MCS) devices for heart failure treatment are typically used as a bridge to heart transplant therapy. The high-risk implantation procedure and secondary complications that accompany MCS typically limit their use to patients with New York Heart Association (NYHA) Class IV heart failure. However, earlier MCS implantation is associated with improved clinical outcomes by avoiding multi-organ dysfunction that often accompanies end-stage heart failure. The goal of this project is to develop a minimally invasive blood pump with good hemocompatibility that can assist the weakened heart during the early stages of heart failure (INTERMACS Level 4-6 or NYHA Class IIIb). The proposed intra-atrial pump (MicroVasc) will be affixed to the atrial septum and work in parallel with the left ventricle (LV) to reduce the LV stroke work. By keeping the LV intact, ventricular function will be preserved, offering the best environment for myocardial reconditioning. This novel assist approach has the potential to slow the progression of heart failure and restore native cardiac function, avoiding the need for heart transplantation or the use of invasive MCS devices. Development of the MicroVasc requires careful design of hydraulic, motor, and bearing systems, all of which must be hemocompatible. This proposal investigates a miniature Maglev motor system for the MicroVasc as well as the hemocompatibility of the hydraulic and motor components. After the pump geometry has been refined to improve hemocompatibility, the MicroVasc will be studied in vitro with a continuous flow blood loop and in vivo with a large animal model to ensure safety and efficacy of the proposed maglev motor system. The MicroVasc, which is designed for early intervention, will improve myocardial reconditioning, advance the technology used in the MCS field, decrease the need for highly invasive MCS device implantation, and drastically reduce the need for heart transplantation.