Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Heart valve – Combined with surgical tool
Reexamination Certificate
2000-12-21
2002-06-25
McDermott, Corrine (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Heart valve
Combined with surgical tool
C606S108000
Reexamination Certificate
active
06409758
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to medical devices, and more particularly to an apparatus for facilitating the implantation of a bioprosthetic replacement heart valve, and associated methodology.
BACKGROUND OF THE INVENTION
In mammalian animals, the heart is a hollow muscular organ having four pumping chambers: the left and right atria and the left and right ventricles, each provided with its own one-way valve. The natural heart valves are identified as the aortic, mitral (or bicuspid), tricuspid and pulmonary valves and have leaflets to control the directional flow of blood through the heart. The valves are each mounted in an annulus that comprises a dense fibrous ring attached either directly or indirectly to the atrial or ventricular muscle fibers. Various surgical techniques may be used to repair a diseased or damaged valve. In a valve replacement operation, the damaged leaflets are excised and the annulus sculpted to receive a replacement valve.
Two primary types of heart valve replacements or prostheses are known. One is a mechanical-type heart valve that uses a ball and cage arrangement or a pivoting mechanical closure to provide unidirectional blood flow. The other is a tissue-type or “bioprosthetic” valve which is constructed with natural-tissue valve leaflets which function much like a natural human heart valve's, imitating the natural action of the flexible heart valve leaflets which form commissures to seal against each other to ensure the one-way blood flow. In tissue valves, a whole xenograft valve (e.g., porcine) or a plurality of xenograft leaflets (e.g., bovine pericardium) provide occluding surfaces that are mounted within a surrounding stent structure. In both types of prosthetic valves, a biocompatible cloth-covered sewing or suture ring is provided on the valve body, for the mechanical type of prosthetic valve, or on the inflow end of the stent for the tissue-type of prosthetic valve.
In placing a tissue type prosthetic valve in the mitral position, the commissure posts are on the blind side of the valve and may become entangled with pre-installed sutures, and may damage the annulus or tissue during delivery. The difficulty of the delivery task is compounded if the surgery is through a minimally-invasive access channel, a technique that is becoming more common. The problem of entanglement is termed “suture looping,” and means that the suture that is used to attach or mount the valve to the heart tissue is inadvertently wrapped around the inside of one or more of the commissure post tips. If this occurs, the looped suture may damage one of the tissue leaflets when tightly tied down, or at least may interfere with valve operation and prevent maximum coaptation of the valve leaflets, resulting in a deficiency in the prosthetic mitral valve.
Some attempts have been made to overcome these problems in current holders for prosthetic mitral valves. An example of such a holder is U.S. Pat. No. 4,865,600, Carpentier, et al., incorporated herein by reference. Carpentier provides a holder having a constriction mechanism that constricts the commissure posts inwardly prior to implantation. The Carpentier device provides an elongate handle to both hold the valve/valve holder combination during implantation, as well as to cause the commissure posts to constrict inwardly. The valve is connected to the valve holder by the manufacturer using one or more sutures, and the combination shipped and stored as a unit. During the valve replacement procedure, the surgeon connects the handle to the holder and locks a locking nut to hold the commissure posts at a given constricted position. The surgeon then attaches the sewing ring of the valve to the native valve annulus with an array of sutures that has been pre-embedded in the annulus and extended outside the body. The valve is then advanced along the array of sutures to its desired implantation position and the sutures tied off. When the holder is cut free, the commissure posts are released to expand and the holder may be removed using the handle. The inability to remove the elongate handle while maintaining commissure constriction is a detriment. The handle must be attached to the holder so that the commissure posts remain in a constricted position during attachment of the array of sutures to the sewing ring. This can be awkward for manipulation of the valve/valve holder combination during this time-constrained operation. Further, the relatively wide holder periphery may interfere with the attachment step.
What is needed then is an improved tissue-type prosthetic valve holder attachable to the inflow end of the valve that can constrict the commissure posts with or without a handle being attached, yet provides improved visibility and accessibility to the surgeon during the valve attachment steps.
SUMMARY OF THE INVENTION
The present invention provides a holder for a tissue-type prosthetic heart valve having an inflow end and an outflow end and a flow axis therebetween. The valve includes an annular suture ring at the inflow end attached to a stent having posts circumferentially-spaced about the flow axis that support occluding tissue surfaces of the valve. In this type of valve the posts are cantilevered generally in the outflow direction.
The holder includes a valve abutment portion sized and shaped to abut the suture ring at the inflow end of the valve. The holder further includes a commissure post constriction mechanism adapted to constrict the commissure posts radially inward from a relaxed position to a constricted position when actuated by a handle adapted to operatively connect to the commissure post constriction mechanism. A retaining mechanism is also provided that retains the commissure post constriction mechanism in the constricted position after the handle is removed.
In one embodiment the commissure post constriction mechanism comprises an adjusting portion and an adjusting member adapted to adjust the distance between the adjusting portion and the valve abutment portion and one or more filaments attached to the adjusting portion and sutured through the end of the commissure posts distal the adjusting portion. When the adjusting member is operated to separate the adjusting portion from the valve abutment portion the adjusting portion pulls the filaments, which in turn urge the end of the commissure posts distal the adjusting portion radially inwardly, to the constricted position.
The valve abutment portion may be of a planar shape, with the adjusting portion of a substantially complementary planar shape to the valve abutment portion. It is preferred that the planar shape of the valve abutment portion be comprised of a plurality of tangs radiating from a central body to each cover a portion of the suture ring. In this manner a sufficient amount of the suture ring is left exposed to allow for suturing the suture ring to the native annulus.
Adjustment of the distance between the valve abutment portion and the adjusting portion may be achieved by providing a central threaded aperture in the adjusting portion and an adjusting member that cooperates with this threaded aperture. In this construction the end of the adjusting member proximal the valve abutment portion abuts the valve abutment portion during operation. When the adjusting member is advanced through the central aperture of the adjusting portion it pushes the valve abutment portion and the two portions separate.
A handle may be operatively connected to the adjusting member to turn it by providing a handle that has an externally threaded end portion and an adjusting member having a central longitudinal threaded bore sized to receive the threaded end of the handle. When the handle is introduced into the bore it is rotated in a first direction and will seat in the threaded bore of the adjusting member. Further rotation of the adjusting member separates the adjusting portion from the valve abutment portion, as recited above, and causes the commissure posts to constrict inwardly.
In the prior art the handle would have to remain attac
Ekholm C. Roger
Jackman Jerry L.
Newborg Steve
Stobie Robert
Ton-That Cuong
Barrett Thomas
Condino Debra D.
Cumberbatch Guy L.
Edwards Lifesciences Corporation
James John Christopher
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