Prosthetic heart valve

Abstract

A bileaflet heart valve incorporates a pivot arrangement that minimizes resistance to downstream blood flow in the open position yet has prompt response and therefore minimal regurgitation upon flow reversal. A valve body having an axially curved entrance that smoothly joins a generally cylindrical body of extended axial length provides excellent fluid flow characteristics when combined with leaflets that can assume orientations perfectly aligned with the downstream flow of blood. Identical flat leaflets can assume a parallel orientation in the fully open position during downstream blood flow or can assume other low energy positions. Flat ears, which extend laterally from opposite surfaces of the leaflets, interengage with cavities of unique design having upstream and downstream lobes separated by an intermediate throat portion defined by inward and outward fulcrums. The downstream lobes may be designed to facilitate movement to the parallel orientation or to cause the leaflets to optionally prerotate toward the closed position. As soon as reverse flow begins, upstream displacement of the leaflets causes the ears to contact straight camming surfaces located upstream of the outward fulcrums which, in combination with the fulcrums and a downwardly directed, concave surface at the upstream end of the upstream lobe, positively guide each leaflet through efficient closing which ends in substantially rotational movement. A pyrocarbon valve body receives suture rings that permit the tissue annulus to directly contact an exterior surface region of the valve body.