Medical Carbon Research Institute, LLC

Carbon Implants, Inc.

Medtronic Carbon Implants, Inc.

John L Ely

Axel D Haubold

Michael R Emken

Jack C Bokros

Jonathan C Stupka

T Scott Peters

C Thomas Waits

James A Accuntius

Joseph P Ritz

A method and apparatus for proof testing an assembled mechanical heart valve prosthesis having a valve body and at least one movable occluder wherein at least one of the components has a surface of nonmetallic crystalline material, such as pyrocarbon, in which microcrack growth may occur. The assembled valve prosthesis is subjected to fluid loading with the occluder in the closed position so as to create omnidirectional pressure of at least 20 psig therewithin on the downstream side of the occluder. During fluid loading of the assembled valve, acoustic monitoring is carried out using a transducer to detect sounds that are indicative of crack nucleation and/or incremental crack extension, based upon a predetermined fail-pass criterion. Any valve prosthesis wherein sounds of a greater magnitude are detected is rejected.

Proof testing of mechanical heart valves

A prosthetic heart valve is shown which incorporates a valve body design and leaflet pivot arrangements that minimize turbulence and shear stresses having a tendency to generate thrombosis. A valve body having an axially curved entrance that is smoothly joined to 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. By constructing such a pyrocarbon valve body which receives a metal ring at an appropriate location, suture rings that permit the tissue annulus to directly contact the exterior surface of the cylindrical valve body are accommodated.

Prosthetic heart valve with improved blood flow

Pure unalloyed pyrocarbons having wear resistance suitable for use in pyrocarbon-coated heart valve components and having mechanical properties, such as flexural strength and toughness, superior to commercial silicon-alloyed pyrocarbons are deposited in fluidized bed coaters. Coating conditions are carefully controlled so as to maintain a precise bed size within a defined coating enclosure which will assure a substantially constant surface deposition temperature that in turn assures deposition of homogenous unalloyed pyrocarbons having these improved mechanical properties.

Pyrocarbon and process for depositing pyrocarbon coatings

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.

Prosthetic heart valve

A bileaflet heart valve is shown which 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. The valve employs a pair of identical flat leaflets that can assume a precisely parallel orientation in the fully open position at or near peak downstream blood flow or can alternatively assume other low energy positions. As the downstream flow of blood slows near the end of a pumping stroke, downstream displacement of the leaflets results in their prerotation toward the closed position orientation, all being controlled by the interengagement of flat ears, which extend laterally from opposite surfaces of the leaflets, and receiving cavities of unique design. The cavities include upstream and downstream lobes separated by an intermediate throat portion defined by inward and outward fulcrums. 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.

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Austin, TX, United States of America

John L Ely