J. Park1, P. Bonde2 1Yale University School Of Medicine,Bonde Artificial Heart Lab,New Haven, CT, USA 2Yale University School Of Medicine,Cardiac Surgery,New Haven, CT, USA
Introduction:
Early class III heart failure patients can benefit greatly from increase in their cardiac output, provided they do not suffer from the adverse events related to current left ventricular assist device (LVAD)s, such as stroke, drive line infections and pump thrombosis. We present an endovascular, totally implantable, on demand cardiac support device with technological sophistication to eliminate common adverse events associated with LVADs.
Methods:
Wirelessly controllable on-demand recover device is composed of four elements: axial pump, two valves, cleaning port, and transcutaneous energy transfer system (TETS). Brushed DC motor (8.5 mm in diameter and 20 mm in length) capable of operating under the maximum unload speed of 52kRPM at 7.4 V was used for manufacturing axial pump in which impeller and diffuser designs were qualified by computational fluid dynamics (CFD). Gear-driven valve was designed to generate open and close maneuver with proper amount of force applied. Objet 30 3D printer with resin material was used to produce watertight prototypes. Performance tests were carried out using mock circulation loop equipped with flowmeter and pressure transducers. Color dyes were used to quantitatively evaluate valve sealing capability and cleaning efficiency. Pump performance and wireless power transfer efficiency were also evaluated by creating pump performance curve that shows flow and pressure relationship and measuring the power successfully delivered to the system respectively.
Results:
Pump performance curve was created by controlling flow with manufactured valves. With two valves closed at the end of the graft where pump are located inside, colored dyes were introduced into the graft and leaking dye concentration was measured, which results in negligible value (< 0.1 ppm). Dyes inside the graft were then cleared out through cleaning ports. Concentration of the dye inside the graft after cleaning successfully dropped near zero (< 0.1 ppm). Pump and valve operations were all achieved by wireless power delivery with an efficiency of 80 %. The device is planned to pump blood from foramina ovale and return to ascending aorta, with ability to shut the inflow and outflow and clean the pump automatically when desired (7 cc volume), thus eliminating any clot formation within the pump.
Conclusion:
An endovascularly deployable, on-demand cardiac support device was successfully tested in-vitro. With its ability to periodically clean and maintain the pump, it eliminates clot formation. Total implantability has the potential to offer better quality of life and acceptability for the early stage class III heart failure patients.
