Abstract
BACKGROUND: Centrifugal pumps are used increasingly for temporary mechanical support for the treatment of cardiogenic shock. However, centrifugal pumps can generate excessive negative pressure and are afterload sensitive. A previously developed modified roller pump mitigates these limitations both in vitro and in preliminary animal experiments. We report the results of intermediate-term testing of our evolving pump technology, known as the BioVAD. METHODS: The BioVAD was implanted in 6 adult male sheep (62.5±3.9 kg), with drainage from the left atrium and reinfusion into the descending aorta. The sheep were monitored for 5 days. Heparin was given during the initial implantation, but no additional anticoagulants were given. Data collected included hemodynamic status, pump flow and pressures, laboratory values to monitor end-organ function and hemolysis, pathologic specimens to evaluate for thromboembolic events and organ ischemia, and explanted pump evaluation results. RESULTS: All animals survived the planned experimental duration and there were no pump malfunctions. Mean BioVAD flow was 3.57±0.30 L/min (57.1 mL/kg/min) and mean inlet pressure was -30.51±4.25 mm Hg. Laboratory values, including plasma free hemoglobin, creatinine, lactate, and bilirubin levels, remained normal. Three animals had small renal cortical infarcts, but there were no additional thromboembolic events or other abnormalities seen on pathologic examination. No thrombus was identified in the BioVAD blood flow path. CONCLUSIONS: The BioVAD performed well for 5 days in this animal model of temporary left ventricular assistance. Its potential advantages over centrifugal pumps may make it applicable for short-term mechanical circulatory support.