Patent Description:
Transcatheter valve repair devices and valves are useful in repairing or replacing defective cardiac valves, typically using a catheter delivery system. One complication that can arise with prosthetic valves is paravalvular leakage, which is blood flowing around the valve, rather than through the valve. This can result when the valve is not properly seated in the native valve annulus, or when there is a pathway for blood to flow between the leaflets of the prosthetic valve and the anchoring structure used to support the prosthetic valve leaflets. The former cause is mitigated through proper valve placement and sizing. The latter form of leakage, however, is typically a result of a design flaw or defective valve mechanism. In <CIT> a stentless support structure is disclosed that comprises a braided tube that is very flexible and, when elongated, becomes very long and very small in diameter, thereby being capable of placement within a small diameter catheter. The support structure is preferably constructed of one or more thin strands of a superelastic or shape memory material such as Nitinol. When released from the catheter, the support structure folds itself into a longitudinally compact configuration. In <CIT> devices and methods for implantation at a native mitral valve are disclosed having a non-circular annulus and leaflets. One embodiment of the device includes a valve support having a first region configured to be attached to a prosthetic valve with a plurality of prosthetic leaflets and a second region. The device can further include an anchoring member having a longitudinal dimension. The present invention is directed toward an improved valve design that reduces or eliminates paravalvular leakage.

The present invention is defined by the appended claims only, in particular by the scope of appended independent claims. References to "embodiments" throughout the description which are not under the scope of the appended claims merely represents possible exemplary executions and are therefore not part of the present invention. One aspect of the invention provides a prosthetic valve design, such as a cardiac valve design, that reduces paravalvular leakage. Leakage is reduced by associating a tissue liner with a mesh support structure. The tissue liner may be preferred over other liners as tissue is impermeable to fluid flow.

Another aspect of the disclosure provides a tissue liner that sits between a middle and outer layer of a mesh valve support.

Yet another aspect of the disclosure provides a tissue liner that is attached to an outer layer of a mesh valve support with at least one suture.

Still another aspect of the disclosure is a prosthetic valve that includes a support structure having a delivery configuration and a delivered configuration, wherein in the delivery configuration the support structure takes the form of an elongated tube, and in the delivered configuration, the support structure folds to take on a form that includes: an outer layer; a middle layer; and an inner layer. The valve device further includes a valve assembly attached to the inner layer of the support structure and including: a wireform that has commissural points and a valve material attached to the wireform to create valve leaflets, said valve material extending from the commissural points of the wireform to form a valve skirt attached to the middle layer of the support structure. The valve device also has an outer liner attached to an inside surface of the outer layer of the support structure.

In another aspect of the disclosure, the device also has a tissue ring attached to the middle layer of the support structure.

In yet another aspect of the disclosure, the device has a valve skirt is attached to an outside surface of the middle layer of the support structure. The valve skirt may alternatively be attached to an inside surface of the middle layer of the support structure.

In one aspect of the disclosure, the support structure comprises a mesh tube.

In another aspect, the outer layer comprises a flared section, an upright section extending from the flared section, a tapered section extending from the upright section, and a first folded section.

In still another aspect of the disclosure, the outer liner is attached to the flared section of the outer layer.

According to the invention, the support structure comprises a braided wire tube with gaps being defined by the braided wire and said outer liner protrudes through the gaps.

One aspect of the disclosure provides a method of preventing paravalvular leakage through a prosthetic valve. The method generally includes the steps of providing a prosthetic valve with a support structure having an outer layer and lining an inside surface of the outer layer with a tissue liner.

In one aspect of the method of the disclosure, the step of lining the inside surface of the outer layer with a tissue liner comprises lining the inside surface of the outer layer with a tissue liner that protrudes through gaps formed in the support structure.

In another aspect of the method of the disclosure, the step of providing the prosthetic valve with the support structure having the outer layer comprises providing the prosthetic valve with the support structure having the outer layer, a middle layer, and an inner layer.

In yet another aspect of the disclosure, the method further comprises attaching a tissue ring to the middle layer.

In still another aspect of the method of the disclosure, the step of providing the prosthetic valve with the support structure having the outer layer further comprises: providing the prosthetic valve with a valve assembly including a length of valve material that is attached to a wireform and extends past the wireform; and attaching the material that extends past the wireform to at least the middle layer of the support structure.

The method of the disclosure may further comprise attaching the material that extends past the wireform to the inner layer of the support structure.

In one aspect of the method of the disclosure, the step of attaching the material that extends past the wireform to the inner layer of the support structure comprises attaching the material that extends past the wireform to an inside surface of the inner layer of the support structure. Alternatively, the step of attaching the material that extends past the wireform to the inner layer of the support structure comprises attaching the material that extends past the wireform to an outside surface of the inner layer of the support structure.

Another aspect of the invention is a prosthetic valve device that includes a support structure having a plurality of layers including at least an outer layer and an inner layer; a valve assembly connected to the inner layer; and a tissue liner lining an inside surface of the outer layer. The valve assembly may include a tissue skirt attached to an inside or outside surface of said inner layer.

Yet another aspect of the disclosure is a prosthetic valve device with a plurality of layers including a middle layer with a tissue ring attached to a surface thereof.

These and other aspects, features and advantages of which embodiments of the invention are capable of will be apparent and elucidated from the following description of embodiments of the present invention, reference being made to the accompanying drawings, in which.

Referring now to the figures there is shown an embodiment of a prosthetic valve <NUM> of the invention. Valve <NUM> generally includes a valve assembly <NUM> and a support structure <NUM>. The valve assembly <NUM> includes valve leaflets <NUM> supported by a wireform <NUM>, which forms commissures <NUM>. The commissures <NUM> may include loops <NUM> for purposes of implantation and retrieval. The valve leaflets <NUM> may be formed from natural tissue, such as porcine tissue. However, synthetic materials may also be used.

The support structure <NUM> may be formed from a tube of material such as a braided mesh, or may be a fenestrated structure cut from a solid tube. Good results have been obtained using a memory metal mesh braid. The structure <NUM> includes several layers that are bordered by folds or creases. Specifically, there is an outer layer <NUM>, a middle layer <NUM>, and an inner layer <NUM>. Middle layer <NUM> and inner layer <NUM> are shown in <FIG> and <FIG>.

The outer layer <NUM> includes various sections that give it a shape suitable for nesting in a native valve annulus, such as a cardiac valve. This shape aids in its ability to prevent paravalvular leaking, as well as ensuring the valve <NUM> will not migrate after implantation. In one embodiment, the outer layer includes a flared section <NUM> that leads to an upright section <NUM>, followed by a tapered section <NUM> and a first folded section <NUM>. One skilled in the art will realize that the transitions between sections <NUM>, <NUM>, and <NUM> may be angular creases, as shown, or may be gradual curved transitions. Moreover, the shape of the outer layer <NUM> may vary.

The middle layer <NUM> includes a second folded section <NUM> that continues from the first folded section <NUM> of the outer layer <NUM>. The second folded section <NUM> leads into an angled section <NUM>, which continues to a third folded section <NUM>.

The inner layer <NUM>, in the embodiment shown in the figures, continues from the third folded section <NUM> and does not necessarily include multiple sections.

Paravalvular leakage is prevented, in part, by strategic placement of material on the various section of the support structure <NUM>. In a first embodiment, shown in <FIG>, includes three protective liners. An outer liner <NUM> is sewn into the inside surface of the outer layer <NUM>. Specifically, the outer liner <NUM> spans the flared section <NUM> and may extend up into the upright section <NUM> and tapered section <NUM>. All of the liners described herein are preferably circumferential. Non-limiting examples of tissue liner materials include: bio-expandable materials, impermeable fabric, compliant polymers, molded polymers, and hydrogels. It has been found that an impermeable tissue liner performs superiorly in comparison to a woven polyester liner by preventing blood flow through the outer layer <NUM> of the support structure <NUM>. Furthermore, in all embodiments, fabric may be adhered to the tissue liners to encourage further ingrowth of native tissue.

The outer tissue liner <NUM> is attached to the outer layer <NUM> of the mesh valve support and the second liner <NUM> is attached to the middle layer <NUM> of the mesh valve support. The tissue liner <NUM> may be designed to protrude through the outer layer <NUM> of the support structure <NUM> to form a seal against the native valve annulus. Providing a tissue liner on the inside surface of the support structure may be advantageous to placement on the outside surface of the support structure <NUM> in that the wire of the support structure is now in contact with the native tissue, providing a higher friction coefficient than a tissue-covered stent. Furthermore, during valve loading and delivery, the wire mesh provides a barrier between the relatively delicate tissue and the stent, minimizing the risk of damaging the tissue layer.

Sealing is enhanced by the tissue protruding through the gaps in the support structure in use. Varying the thickness of the liner, and/or the size of the gaps of the support structure, will provide different degrees of protrusion. The protrusion effect can be further enhanced by forming the middle layer <NUM> to have elbows that act on the inside surface of the liner <NUM> to push it through the outer layer <NUM>.

The second liner <NUM> may be in the form of a tissue ring and may be sewn through the middle layer <NUM> of the mesh support <NUM> to make intimate contact with the tissue skirt coming off the valve leaflets, described below. Specifically, the tissue ring <NUM> is located on an outer surface of the middle layer <NUM> on the angled section <NUM>, and may extend onto the third folded section <NUM>. The tissue ring <NUM> may include bio expandable materials, impermeable fabric, compliant polymers, molded polymers, and hydrogels, just to name a few non-limiting examples.

The tissue ring <NUM> enhances the sealing between the mesh layers by compressing against the tissue liners in between the layers of mesh, acting like a gasket or an o-ring. Different annulus sizes alter the height of the valve and can alter the location of the mating surfaces. As such, the tissue ring <NUM> is adaptable to many annulus sizes with the same mesh structure since the ring <NUM> is smaller than the tissue liner <NUM> and can align itself anywhere along the length. The tissue ring <NUM> may be made, in conjunction with the mesh density, to match the diamond pattern of the middle layer <NUM> to enhance protrusion through the mesh gaps. The tissue ring <NUM> may be attached to the middle layer <NUM> using a variety of means. Non-limiting examples include: suture knots, running suture stitches, metal crimps, adhesive, cauterization, and laser adhesion.

The third liner, the inner liner <NUM>, is an extension, or skirt, of the valve leaflets <NUM>. In a first embodiment, shown in <FIG>, the extra material of the valve leaflets <NUM>, forming the inner liner <NUM>, extends into the fold between the third folded section <NUM> of the middle layer <NUM> and the inner layer <NUM>.

In a second embodiment, shown in <FIG>, the extra material of the valve leaflets <NUM>, forming the inner liner <NUM>, is routed to an inside surface of the inner layer <NUM>, and wraps around the third folded section <NUM> of the middle layer <NUM>.

Each of the embodiments of the device <NUM> described herein has a delivery configuration and a deployed configuration. In the delivery configuration, the folds are straightened and the mesh support structure is in the form of an elongated tube. The liners are attached to the support structure such that, upon folding, the liners are appropriately placed.

The delivery configuration of the embodiment of <FIG> is shown in <FIG> shows that in the delivery configuration, support structure <NUM> is a continuous tube that includes layers <NUM>, <NUM> and <NUM>. When extended the order, moving from left to right as shown, of the various sections and layers becomes outer layer <NUM>, with sections <NUM>, <NUM>, <NUM> and <NUM>. Liner <NUM> is contained within the support structure <NUM> and generally aligned with the outer layer <NUM>. Next is middle layer sections <NUM>, <NUM> and <NUM>. Tissue ring <NUM> is attached to the inner surface of the support structure <NUM> at the tapered section <NUM> of the middle layer <NUM>. The support structure <NUM> terminates with the inner layer <NUM>. The wireform <NUM> is attached on an outside surface of the support structure <NUM> at the inner layer <NUM>. The valve tissue <NUM> is attached to the wireform <NUM> and includes the skirt that forms the inner liner <NUM>. The tissue <NUM> thus extends past the end of the wireform and along the outside surfaces of the inner layer <NUM> and middle layer <NUM>.

Claim 1:
A prosthetic valve device comprising a support structure, wherein
the support structure (<NUM>) is formed from a braided wire tube defining gaps and folds upon delivery to form an outer layer (<NUM>) and an inner layer (<NUM>);
a valve assembly (<NUM>) connected to the inner layer;
a liner (<NUM>) lining an inside surface of the outer layer, wherein the liner protrudes through the gaps.