Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Heart valve – Flexible leaflet
Reexamination Certificate
1999-04-16
2001-09-04
Isabella, David J. (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Heart valve
Flexible leaflet
Reexamination Certificate
active
06283994
ABSTRACT:
FIELD OF THE INVENTION
The present invention is related to valves and in particular to heart valve prostheses having a plurality of flexible leaflets.
BACKGROUND OF THE INVENTION
Ever since 1950, when blood oxygenators made open heart surgery feasible, it has been possible to treat some forms of heart disease by replacing one of the patient's heart valves with a prosthetic valve. Early heart valve prostheses included ball-and-cage valves and disc-and-cage valves in which a ball or a disc was housed in a cage. One side of the cage provided an orifice through which blood flowed either into or out of the heart, depending on the valve being replaced. When blood flowed in a forward direction, the energy of the blood flow forced the ball or disc to the back of the cage allowing blood to flow through the valve. When blood attempted to flow in a reverse direction, or “regurgitate”, the energy of the blood flow forced the ball or disc into the orifice in the valve and blocked the flow of blood.
A bi-leaflet valve comprised an annular valve body in which two opposed leaflet occluders were pivotally mounted. The occluders were substantially rigid and moved between a closed position, in which the two leaflets were mated and blocked blood flow in the reverse direction, and an open position, in which the occluders were pivoted away from each other and did not block blood flow in the forward direction. The energy of blood flow caused the occluders to move between their open and closed positions.
A tri-leaflet valve comprised an annular valve body in which three leaflets were mounted to a portion of the valve body, called a “stent,” located at the circumference of the annulus. When blood flowed in the forward direction, the energy of the blood flow deflected the three leaflets away from the center of the annulus and allowed blood to flow through. When blood flowed in the reverse direction, the three leaflets engaged each other in a coaptive region, occluded the valve body annulus and prevented the flow of blood. The valve leaflets were made from tissue, such as specially treated porcine or bovine pericardial tissue, or from man-made materials such as ceramic materials, elastomers or other biocompatible polymers.
It is important in heart valve design to reduce the forward (systolic) pressure necessary to open the heart valve.
SUMMARY OF THE INVENTION
In general, in one aspect, the invention features a heart valve comprising a valve body having an axis. A plurality of flexible leaflets is coupled to the valve body. Each of the plurality of leaflets has an open position and a closed position. Each of the plurality of leaflets has a bottom and each of the plurality of leaflets has a center of a free margin. One or more of the plurality of leaflets comprises a spine. The spine has a different curvature than the non-spine portion of the leaflet. The spine comprises a longitudinal axis. The inclination of the axis of the spine with respect to a line from the bottom of the leaflet to the center of the free margin is less than 10 degrees.
Implementations of the invention may include one or more of the following. The axis of the spine may be parallel to the line from the bottom of the leaflet to the center of the free margin.
In general, in another aspect, the invention features a heart valve comprising a valve body having an axis. A plurality of flexible leaflets is coupled to the valve body. Each of the plurality of leaflets has an open position and a closed position. One or more of the plurality of leaflets comprises a longitudinal spine. The spine has an axis and the inclination of the spine axis with respect to the valve body axis is greater than 0 degrees.
Implementations of the invention may include one or more of the following. The inclination of the spine axis with respect to the valve body axis may be greater than 5 degrees.
In general, in another aspect, the invention features a heart valve comprising a valve body having an axis. The valve body has an orifice, the orifice having an inside diameter. The heart valve comprises a plurality of flexible leaflets. One or more of the plurality of leaflets comprises a spine. The one or more leaflets with a spine further comprise a transition point between the spine and the non-spine portion of the leaflet. The transition point is located at a distance from the axis. The distance is at least twenty percent of the distance from the axis to the inside of the valve body.
In general, in another aspect, the invention features a heart valve comprising a valve body and a plurality of flexible leaflets coupled to the valve body. The plurality of leaflets has an open position and a closed position. Each of the plurality of leaflets comprises a belly when the plurality of leaflets are in their respective closed positions. The belly of one or more of the plurality of leaflets has a continuous curvature except for a non-continuous portion.
Implementations of the invention may include one or more of the following. The non-continuous portion of the belly may be generally cylindrical. The non-continuous portion of the belly may be generally planar. The continuous portion of the belly may have a generally cylindrical shape having a first axis and the non-continuous portion of the belly may have a generally cylindrical shape having a second axis. The first axis may intersect the second axis above the intersection of the leaflet and the valve body. The non-continuous portion may have a longitudinal axis and a cross-section of the non-continuous portion generally perpendicular to the axis of the spine may be generally V-shaped. The belly of the one or more of the plurality of leaflets may be symmetrical about an axis. The non-continuous portion may have a longitudinal axis. The belly axis may not coincide with the axis of the non-continuous portion. Each of the one or more of the plurality of leaflets may have a center of a free margin and a bottom point. The non-continuous portion may have a longitudinal axis extending along a line from the bottom point of the leaflet to the center of the free margin of the leaflet.
In general, in another aspect, the invention features a heart valve comprising a valve body and a plurality of flexible leaflets coupled to the valve body. Each leaflet has a thickness. Each of the one or more of the plurality of leaflets comprises a buckle-susceptible portion, the thickness of the buckle-susceptible portion being different from the thickness of the remaining portion of the leaflet.
Implementations of the invention may include one or more of the following. The thickness of the buckle-susceptible portion may be less than the thickness of the remaining portion of the leaflet. The thickness of the buckle-susceptible portion may not be uniform.
In general, in another aspect, the invention features a method for opening a closed heart valve comprising a plurality of flexible leaflets, comprising experiencing pressure from an inflow direction of the valve. The method further comprises collapsing a spine portion of a leaflet before the remaining portion of the leaflet collapses.
Implementations of the invention may include one or more of the following. The leaflet has a thickness and the spine portion may comprise a region where the leaflet has a decreased thickness. Each of the plurality of leaflets may have an open position and a closed position. Each of the plurality of leaflets may have a center of a free margin when it is in its respective closed position. The method may comprise pulling the center of the free margin of the leaflet with the spine away from the centers of the free margins of the other leaflets before the remaining portion of the leaflet pulls away from the other leaflets by the spine portion of the leaflet collapsing and pulling the center of the free margin. Collapsing may comprise retaining generally the curvature of the spine portion of the leaflet. Collapsing may comprise changing the curvature of the spine portion of the leaflet from a flat curvature to a curvature that is convex, deflected in the direction of the pr
Gong Xiao-Yan
Moe Riyad E.
Sarnowski Edward J.
Isabella David J.
Loo Blossom E.
Lyren Phillip S.
Scott Timothy L.
Sulzer Carbomedics Inc.
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