Prosthetic valve selection for a pulsatile LVAD.

Abstract

During the final development of a unique Magnetically Actuated Left Ventricle Assist Device (MALVAD), three of the most widely used clinical prosthetic valves were evaluated to determine their suitability for the stringent requirements for LVAD use, in both the inflow and outflow positions. The three valves (St. Jude Medical-SJM; Medtronic Hall-MH; Bjork-Shiley Convex-Concave-BSCC), with lumen size of 25 mm, were tested in the same appropriate mock loop to the following set of hydraulic parameters: 1) after-load systemic pressure = constant 100 mmHg; 2) preload pressure ranged from 3 mm to 18 mmHg; 3) beat rate ranged from 60 bpm to 80 bpm. Pump actuator power was held constant, correspondent with specific bpm rate, for all valves tested. Results from a series of 10 bench tests per valve showed that the SJM was significantly better, on a statistical basis, than both the MH and BSCC valves, at fill pressures of 5 mmHg. At 10-mm fill pressure, however, the statistical flow rates for both the SJM and the MH valves were significantly superior to the BSCC valve, so that the BSCC valve was classified as a marginal candidate for LVAD use. The SJM and MH valves had bench test flow-rate values whose numerical difference was too small to serve conclusively as an arbitrary basis for valve choice. Because of this, the two valves were further evaluated in terms of two widely recognized, mandatory LVAD valve design criteria: (1) comparative mechanical ruggedness, and (2) relative ease and simplicity of LVAD design inclusion.(ABSTRACT TRUNCATED AT 250 WORDS)