Acute and Chronic Pre-Clinical Implants of the CorWave LVAD: Hydraulic, Hemocompatibility and Hemodynamic Results

Abstract

The CorWave LVAD employs a unique "wave membrane" technology, inspired from the motion of aquatic animals, to generate blood flow. This low shear method of blood propulsion can be rapidly modulated to produce a physiologic pulse. The present study evaluated the hydraulic, hemodynamic and hemocompatibility performance of the device in vitro and in animal implants. The pump membrane, oscillation frequency and magnitude, and blood flow path were simulated by CFD analysis in COMSOL and refined to improve hydraulic efficiency and eliminate areas of flow stagnation. Hydraulic testing in a mock circulatory loop and hemolysis measurements in static and pulsatile conditions were then performed in vitro. Acute and chronic implants of the improved pumps were carried out in sheep. The device was successfully operated in 4 different modes: continuous or fixed (similar to rotary VADs with a constant operating point), synchronous co-pulsation and counter-pulsation, and asynchronous pulsation modes. Sensorless detection of native ventricle systole was developed using a mock circulatory loop, with performance confirmed in acute implants in sheep with induced heart failure. The pump could generate average flow rates of 6+ lpm against physiologic pressure, and instantaneous flow rates exceeding 12 LPM during pulsatile operation. Acute and chronic animal implants (up to 60+ days) demonstrated low hemolysis and an absence of significant thrombus or thromboembolic events. The first long-term chronic animal studies of the CorWave LVAD validated the hemocompatibility and hemodynamic performance of the pump. The ability to restore physiologic pulsatility by sensorless synchronization with the native heart was demonstrated in pre-clinical implants. Extensive computational simulation and bench top testing were used to optimize this unique LVAD, displaying the full flow capacity and adding physiologically relevant pulsatility without excessive shear rates.