Preliminary In Vivo Testing of a Novel Pump for Short-Term Extracorporeal Life Support

Abstract

Blood pumps used for temporary circulatory support have limitations. We propose a novel device designed for short-term extracorporeal support that is intrinsically volume responsive, afterload insensitive, and incapable of cavitation or excessive hemolysis. After in vitro testing, we performed the initial in vivo implantations and assessments. The BioVAD prototype (MC3, Inc, Ann Arbor, MI) was implanted in 6 adult male sheep (60.2±2.8 kg) through the left ventricular apex and descending thoracic aorta. Arterial, left and right atrial, and pump inlet and outlet pressures and BioVAD flow were measured and recorded. The animals were volume loaded to assess volume responsiveness, and the inlet lines were abruptly clamped during maximum support to observe for cavitation. An acute heart failure model was created with rapid ventricular pacing, and the animals were supported for 4 hours. Peak flow was 3.19±0.56 L/min and increased to 3.71±0.53 L/min with 20 mm Hg vacuum-assisted drainage. Without manual changes in pump settings, pump flow increased 17.5% with volume loading. During acute venous line occlusion, there was no evidence of cavitation, and inlet suction was minimal. Hemodynamics were maintained for 4 hours during acute heart failure. The BioVAD provided adequate flow in an acute in vivo model. Its design may be superior for short-term extracorporeal support.