Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Heart valve – Flexible leaflet
Reexamination Certificate
1998-10-16
2001-08-07
Snow, Bruce (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Heart valve
Flexible leaflet
C623S900000
Reexamination Certificate
active
06270527
ABSTRACT:
TECHNICAL FIELD
The present invention pertains to valves and in particular to tri-leaflet heart valve prostheses.
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 typically substantially rigid, although some designs incorporated flexible leaflets, 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 flexible leaflets were mounted to a portion of the valve body, called a “stent,” located at the circumference of the annulus. Some tri-leaflet valves used rigid leaflets. 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 a man-made material such as polyurethane or another biocompatible polymer.
A heart valve is implanted into an annular opening in a heart created when the diseased valve is removed. The valve can be secured in the annulus through the use of sutures or pins that penetrate the host tissue and an outside edge of the valve. Alternatively, a sewing ring can be attached, typically with sutures, to the elastic valve. The valve can then be secured in the annulus by suturing the host tissue to the sewing ring.
An important consideration in prosthetic heart valve design is the durability of the heart valve. Replacing a prosthetic heart valve after it has been implanted is dangerous and expensive for the patient and failure of a prosthetic heart valve can cause the death of a patient. One source of prosthetic heart valve failure is tearing of the elastic material that forms the heart valve.
SUMMARY OF THE INVENTION
The invention improves the durability of elastic heart valves by eliminating the need to pierce the elastic material of the heart valve during construction of the sewing ring or during implantation.
In general, in one aspect, the invention features a valve comprising an elastic valve body and a stent, a first portion of the stent being embedded in the elastic valve body and a second portion of the stent being outside the valve body.
The invention may include one or more of the following. A sewing ring may be coupled to the second portion of the stent. The coupling may be provided by sutures. The coupling may be provided by a cloth. A coupling element may be coupled to the second portion of the stent and the sewing ring may comprise sewing ring fabric. The sewing ring may be coupled to the coupling element by wrapping the sewing ring fabric around the second element. The valve body may comprise an embedding layer for embedding the first portion of the stent. The embedding layer may comprise a first portion for embedding a peak of the stent and a second portion for embedding a base of the stent. The valve body may comprise silicon. The valve body may comprise an elastic material and the stent may be encapsulated by the elastic material of the valve body. The stent may be insert molded into the valve body. The valve body may comprise molded features that mechanically capture the stent.
In general, in another aspect, the invention features a valve comprising an elastic valve body, a stent engaged with the valve body, a sewing ring, and a coupling between the sewing ring and the stent.
In general, in another aspect, the invention features a method for manufacturing a valve comprising forming a valve body from elastic material, embedding a first portion of a stent in the elastic material, and leaving outside the elastic material a second portion of the stent.
REFERENCES:
patent: 4297749 (1981-11-01), Davis et al.
patent: 4605407 (1986-08-01), Black et al.
patent: 5411552 (1995-05-01), Andersen et al.
patent: 5489297 (1996-02-01), Duran
patent: 5545215 (1996-08-01), Duran
patent: 5855597 (1999-01-01), Jayaraman
patent: 5855601 (1999-01-01), Bessler et al.
patent: 6027525 (2000-02-01), Suh et al.
patent: 0 850 607 A1 (1998-01-01), None
patent: WO 97/19655 (1997-05-01), None
Campbell Louis A.
Moe Riyad
Barrow Kenneth S.
Lyren Philip S.
Scott Timothy L.
Snow Bruce
Sulzer Carbomedics Inc.
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