Implantable prosthetic valve with non-laminar flow

Abstract

A valve prosthesis device and methods for deployment is disclosed. The device comprises an expandable support stent and a valve assembly comprising a flexible conduit having an inlet end and an outlet, made of pliant material attached to the support beams providing collapsible slack portions of the conduit at the outlet. Flow is allowed to pass through the valve prosthesis device from the inlet to the outlet, but reverse flow is prevented as the collapsible slack portions of the valve assembly collapse inwardly. The device is configured so that retrograde flow will be altered from laminar flow and directed towards the leaflets to effect closing. The device can be deployed in a native heart valve position using a deployment catheter advanced through a body lumen such as a blood vessel, including an aorta.

Claims

1. A valve prosthesis device suitable for cardiac implantation in corporeal ducts, the device comprising: a support stent comprising an inlet portion and an outlet portion narrower than the inlet portion, wherein the support stent comprises an annular frame adapted to be crimped in a first narrow configuration and be radially deployable so as to extend to a second expanded configuration to occupy a passage at the target location for implantation in the corporeal duct, a valve assembly comprising a flexible conduit formed from pliant material formed into leaflets and having an inlet and an outlet, wherein the flexible conduit provides collapsible slack portions arranged to open to permit fluid flow from the inlet to the outlet and to collapse to prevent fluid flow from the outlet to the inlet, and a connection structure that supports the valve assembly in the support stent such that the inlet of the valve assembly is spaced radially inwardly of the support stent and forms an annular space between an inner surface of the support stent and the valve assembly at the inlet of the valve assembly when the support stent is in the second expanded configuration; wherein the annular space is defined between the inner surface of the support stent and an outer surface of the valve assembly along a radius of the prosthesis device extending through the inner surface of the support stent and the outer surface of the valve assembly at the inlet of the valve assembly; wherein when flow is allowed to pass through the valve prosthesis device from the inlet to the outlet, the valve assembly is kept in an open position; and wherein a reverse flow is prevented as the collapsible slack portions of the valve assembly collapse inwardly providing blockage to the reverse flow, wherein the annular space extends from the inlet to the outlet of the valve assembly.

2. The valve prosthesis of claim 1, wherein the support stent comprises a deployable construction adapted to be initially crimped in a narrow configuration suitable for catheterization through the body duct to a target location and adapted to be deployed by means of a deployment device to a deployed state in the target location.

3. The valve prosthesis of claim 1, wherein the device is configured so that an artificial sinus is formed adjacent to the valve assembly.

4. The valve prosthesis of claim 1, wherein the support stent is provided with a plurality of longitudinally rigid support beams of fixed length.

5. The valve prosthesis of claim 4, wherein the valve assembly is attached to the support beams via the connection structure.

6. The valve prosthesis device of claim 1, wherein said valve assembly has a tricuspid configuration.

7. The valve prosthesis device of claim 1, wherein the valve assembly is made from pericardial tissue, or other biological tissue.

8. The valve prosthesis device of claim 1, wherein when the valve assembly leaflets are in the collapsed state substantial portions of the leaflets fall on each other creating better sealing.

9. The valve prosthesis device of claim 1, wherein the support stent is provided with heavy metal markers so as to enable tracking and determining the valve device position and orientation.

10. The valve prosthetic device of claim 1, wherein the support stent is adapted to be deployed by exerting substantially radial forces from within by means of a deployment device to a deployed state in the target location.

11. The valve prosthetic device of claim 1, wherein the support stent at the outlet is wider in diameter than the pliant material forming the conduit.

12. The valve prosthetic device of claim 1, wherein the device is configured to be deployed with an expandable balloon.

13. The valve prosthetic device of claim 1, wherein the support stent when deployed has a diameter in the range of about 19 mm to about 26 mm.

14. The valve prosthetic device of claim 1, wherein the support stent is made from nickel titanium.

15. The valve prosthetic device of claim 1, wherein the support stent comprises hooks to secure the device in position after implantation.

16. The prosthetic heart valve of claim 1, wherein the valve assembly has a cross-sectional area from about 40% to 80% of a cross-sectional area of the support stent across a midsection of the support stent.

17. A prosthetic heart valve, comprising: a support stent comprising an inlet end and an outlet end, the support stent tapering from a first diameter at the inlet end to a second, smaller diameter at the outlet end, wherein the support stent comprises an annular frame adapted to be crimped in a first narrow configuration and be radially deployable so as to extend to a second expanded configuration to occupy a passage at the target location for implantation in the corporeal duct; and a valve assembly comprising a flexible conduit formed from pliant material formed into leaflets and having an inlet and an outlet, wherein the flexible conduit provides collapsible slack portions arranged to open to permit fluid flow from the inlet to the outlet and to collapse to prevent fluid flow from the outlet to the inlet; a connection structure that supports the valve assembly in the support stent such that the valve assembly is spaced radially inwardly of an inner surface of the support stent at the inlet of the valve assembly so as to define an annular space between the inlet of the valve assembly and the support stent when the support stent is in the second expanded configuration; wherein the annular space is defined between the inner surface of the support stent and an outer surface of the valve assembly along a radius of the prosthesis device extending through the inner surface of the support stent and the outer surface of the valve assembly at the inlet of the valve assembly; wherein when flow is allowed to pass through the valve prosthesis device from the inlet to the outlet, the valve assembly is kept in an open position; and wherein a reverse flow is prevented as the collapsible slack portions of the valve assembly collapse inwardly providing blockage to the reverse flow, wherein the annular space extends from the inlet to the outlet of the valve assembly.

18. The prosthetic heart valve of claim 17, wherein the support stent further comprises hooks to secure the prosthetic heart valve in place after implantation.

19. The prosthetic heart valve of claim 17, wherein there are three leaflets and each leaflet comprises opposing sides with each side being paired with an adjacent side of an adjacent leaflet to form three pairs of adjacent sides, wherein each pair of adjacent sides is spaced radially inwardly of the inner surface of the support stent.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) To better understand the present invention and appreciate its practical applications, the following Figures are provided and referenced hereafter. It should be noted that the Figures are given as examples only and in no way limit the scope of the invention as defined in the appended claims.

(2) FIG. 1 represents an oblique view of an embodiment of the invention:

(3) FIG. 2 represents a cross-sectional view across line 2-2 of the embodiment shown in FIG. 1;

(4) FIG. 3 represents an oblique, partly cross-sectional view of another embodiment of the invention; and

(5) FIG. 4 represents a cross-sectional view across line 4-4 of the embodiment shown in FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

(6) A main aspect of the present invention is the introduction of several novel designs for an implantable prosthetic valve. Another aspect of the present invention is the disclosure of several manufacturing methods for implantable prosthetic valves in accordance with the present invention. A further aspect of the present invention is the provision of novel deployment and positioning techniques suitable for the valve of the present invention.

(7) Basically the implantable prosthetic valve of the present invention comprises a leaflet-valve assembly, preferably tricuspid but not limited to tricuspid valves only, consisting of a conduit having an inlet end and an outlet, made of pliant material arranged so as to present collapsible walls at the outlet. The valve assembly is mounted on a support structure or frame such as a stent adapted to be positioned at a target location within the body duct and deploy the valve assembly by the use of deploying means, such as a balloon catheter or similar devices. In embodiments suitable for safe and convenient percutaneous positioning and deployment the annular frame is able to be posed in two positions, a crimped position where the conduit passage cross-section presented is small so as to permit advancing the device towards its target location, and a deployed position where the frame is radial extended by forces exerted from within (by deploying means) so as to provide support against the body duct wall, secure the valve in position and open itself so as to allow flow through the conduit.

(8) The valve assembly can be made from biological matter, such as a natural tissue, pericardial tissue or other biological tissue. Alternatively, the valve assembly may be made form biocompatible polymers or similar materials. Homograph biological valves need occasional replacement (usually within 5 to 14 years), and this is a consideration the surgeon must take into account when selecting the proper valve implant according to the patient type. Mechanical valves, which have better durability qualities, carry the associated risk of long-term anticoagulation treatment.

(9) The frame can be made from shape memory alloys such as nickel titanium (nickel titanium shape memory alloys, or NiTi, as marketed, for example, under the brand name Nitinol), or other biocompatible metals. The percutaneously implantable embodiment of the implantable valve of the present invention has to be suitable for crimping into a narrow configuration for positioning and expandable to a wider, deployed configuration so as to anchor in position in the desired target location.

(10) The support stent is preferably annular, but may be provided in other shapes too, depending on the cross-section shape of the desired target location passage.

(11) Manufacturing of the implantable prosthetic valve of the present invention can be done in various methods, by using pericardium or, for example, by using artificial materials made by dipping, injection, electrospinning, rotation, ironing, or pressing.

(12) The attachment of the valve assembly to the support stent can be accomplished in several ways, such as by sewing it to several anchoring points on the support frame or stent, or riveting it, pinning it, adhering it, or welding it, to provide a valve assembly that is cast or molded over the support frame or stent, or use any other suitable way of attachment.

(13) To prevent leakage from the inlet it is optionally possible to roll up some slack wall of the inlet over the edge of the frame so as to present rolled-up sleeve-like portion at the inlet.

(14) Furthermore, floating supports may be added to enhance the stability of the device and prevent it from turning inside out.

(15) An important aspect of certain embodiments of the present invention is the provision of rigid support beams incorporated with the support stent that retains its longitudinal dimension while the entire support stent may be longitudinally or laterally extended.

(16) The aforementioned embodiments as well as other embodiments, manufacturing methods, different designs and different types of devices are discussed and explained below with reference to the accompanying drawings. Note that the drawings are only given for the purpose of understanding the present invention and presenting some preferred embodiments of the present invention, but this does in no way limit the scope of the present invention as defined in the appended claims.

(17) FIGS. 1 and 2 illustrate a general tricuspid implantable prosthetic valve 10 in accordance with a preferred embodiment of the present invention, suitable for percutaneous deployment using an expandable stent or similar deploying means, shown in its deployed position. Valve 10 comprises a valve assembly 20 having an inlet 22 and an outlet 24, the outlet walls consisting of collapsible pliant leaflet material 26 that is arranged to collapse in a tricuspid arrangement. Valve assembly 20 is attached to an annular support stent 32, the one in this figure being a net-like frame designed to be adapted to crimp evenly so as to present a narrow configuration and be radially deployable so as to extend to occupy the passage at the target location for implantation in a body duct. Support beams 34 are provided on annular support stent 32 to provide anchorage to valve assembly 20. Support beams 34 are optionally provided with bores 36 to allow stitching of valve assembly 20 to support beams 34 by thread, wire, or other attachment means.

(18) The proximal portion 38 of support stent 32 is snuggly fit or fastened to the proximal portion of valve assembly 20 so that any flow is only into inlet 22. In the particular embodiment depicted, the proximal portion of the valve assembly 20 is rolled over the support stent 32 at the inlet 22, thereby forming a rolled-up sleeve-like portion 21 that prevents leakage. Optionally the radial sections 23 of each leaflet 26 are closed by stitching, gluing or other means to narrow outlet 24 while leaving the slack portions 25 free. The distal portion 42 of support stent 32 is narrower than proximal portion 38. The combination of the effect on flow characteristics due to the narrowing of support stent 32 and the narrowing of outlet 24 is sufficient to engender the desired effect or flow characteristics, namely, non-laminar retrograde flow that will assist in the closing of leaflets 26.

(19) Another embodiment of the invention is shown in FIGS. 3 and 4. A prosthetic valve 50 comprises a valve assembly 52 positioned within a support stent 54. The proximal 56 and distal 58 portions of support stent 54 are narrow as compared to the mid-portion 60 of support stent 54, where valve assembly 52 is positioned. Within support stent mid-portion 60 valve assembly 52 is preferably positioned co-axially and at a small distance, for example, from 0.5 to 3 cm, from the interior surface 64 of support stent 54. Valve assembly 52 is attached by connecting membrane 66 to stent supports 68, which optimally have holes or projections 70 to anchor said membranes 66. Any annular space between interior surface 64 and valve assembly 52 is filled with appropriate material to prevent flow around valve assembly 52. Valve leaflets are shown in closed 72 and open 74 positions.

(20) The effective cross-sectional area of valve assembly 52 will preferably be from about 40 to 80% of the cross-sectional area across support stent midsection 60.

(21) The preferred embodiments representing an implantable prosthetic valve in accordance with the present invention are relatively easy to manufacture as they are generally flat throughout most of the production process and only at the final stage of mounting the other elements of the valve assembly on the support frame, a three dimensional form is established.

(22) A typical size of an aortic prosthetic valve is from about 19 to about 26 mm in diameter. A maximal size of a catheter inserted into the femoral artery should be no more than 9 mm in diameter. The present invention introduces a device, which has the ability to change its diameter from about 4 mm to about 26 mm. Artificial valves are not new; however, artificial valves in accordance with the present invention posses the ability to change shape and size for the purpose of delivery and as such are novel. These newly designed valves require new manufacturing methods and technical inventions and improvements, some of which were described herein.

(23) As mentioned earlier, the material of which the valve is made from can be either biological or artificial. In any case new technologies are needed to create such a valve.

(24) To attach the valve to the body, the blood vessels determine the size during delivery, and the requirements for it to work efficiently, there is a need to mount it on a collapsible construction which can be crimped to a small size, be expanded to a larger size, and be strong enough to act as a support for the valve function. This construction, which is in somewhat similar to a large stent, can be made of different materials such as Nitinol, biocompatible stainless steel, polymeric material or a combination of all. Special requirement for the stent are a subject of some of the embodiments discussed herein.

(25) The mounting of the valve onto a collapsible stent is a new field of problems. New solutions to this problem are described herein.

(26) Another major aspect of the design of the valve of the present invention is the attachment to the body.

(27) In the traditional procedure the valve is sutured in place by a complicated suturing procedure. In the case of the percutaneous procedure there is no direct access to the implantation site therefore different attachment techniques are needed.

(28) Another new problem that is dealt herein is the delivery procedure, which is new and unique. Positioning of the device in the body in an accurate location and orientation requires special marking and measuring methods of the device and surgical site as was disclosed herein.

(29) Artificial polymer valves require special treatment and special conditions when kept on a shelf, as well as a special sterilization procedure. One of the consequences of the shelf treatment is the need to crimp the valve during the implantation procedure. A series of devices and inventions to allow the crimping procedure are disclosed herein.

(30) It should be clear that the description of the embodiments and attached Figures set forth in this specification serves only for a better understanding of the invention, without limiting its scope as covered by the following claims.

(31) It should also be clear that a person skilled in the art, after reading the present specification could make adjustments or amendments to the attached Figures and above described embodiments that would still be covered by the following claims.