Long-Term Safety and Durability of Novel Intra-Aortic Percutaneous Mechanical Circulatory Support Device

Abstract

<h3>Purpose</h3> Intra-aortic percutaneous mechanical circulatory support (pMCS) devices have potential to safely treat pre-end stage heart failure patients by reducing cardiac afterload and increasing renal perfusion with no hardware in the left ventricle, across the aortic valve, or above the aortic arch. A challenge for home ambulatory use targeting indications such as bridge-to-recovery or bridge-to-transplant is achieving long-term durability and retrievability without design elements that constrain home use or reduce quality-of-life. <h3>Methods</h3> Intra-aortic pMCS devices were implanted in 4 sheep above the renal arteries by withdrawing the deployment sheath to allow expandable atraumatic struts to engage the aortic wall. The pumps required only electrical power and the 6 Fr power leads were tunneled and externalized on the animals' flanks. All animals were initially cross-tied and infused with heparin for several days before switching to subcutaneous enoxaparin and being allowed to roam their pens. The pumps operated with vest mounted controllers and 1-pound, smart-phone-sized, 10-hour batteries. Study outcomes were pump durability, thrombus formation, hemolysis, operating uptime, and targeted necropsy with histopathology performed by independent laboratory staff. <h3>Results</h3> Pumps operated for 90-142 days limited only by animal activity (snagging, chewing) that pulled 3 of 4 pumps from their initial position; 2 were pulled into the femoral artery and 1 remained super renal. The remaining animal was electively sacrificed at 142 days. Pump flow was blocked in one of the pumps pulled into the femoral artery and minor thrombus was observed at necropsy. The other 3 pumps were thrombus free and appeared unchanged from implant. No pumps showed any degree of adhesion between the struts and the aortic wall. Bearing surfaces on all pumps showed minimal wear consistent with those from pumps run for only 7 days <i>in vivo</i>. There was no clinically significant hemolysis. Aorta histopathology revealed no device-related trauma, endothelialization, or adhesion. Kidney histopathology showed no pump-related findings. <h3>Conclusion</h3> Safe, long-term use of the intra-aortic pMCS device has been demonstrated in a preclinical model. With no significant findings in bearing wear, pump/tissue interface, or end organs, home ambulatory use of this type of system for 6 to 12 months appears feasible.