WO2018050200A1

WO2018050200A1 - Heart implant

Info

Publication number: WO2018050200A1
Application number: PCT/EP2016/001561
Authority: WO
Inventors: Raz Bar-On; Stefan Menzl; Laura FIGULLA; Niklas Maximilian NATHE; Leah KIDNEY; Tobias Caine ROKOSCH; Mario HEINTZE; Youssef Biadillah; Thomas Gerhardt
Original assignee: Coramaze Technologies Gmbh
Priority date: 2016-09-16
Filing date: 2016-09-16
Publication date: 2018-03-22

Abstract

The invention relates to a heart implant, particularly being configured to reduce or eliminate a heart valve insufficiency after implantation into the heart, comprising a closure element being positionable within the heart valve annulus, particularly being configured to close or at least to reduce a remaining gap between closing valve leaflets, an anchoring element being attached to the closure element for fixing the implant in the heart, preferably for non-invasive fixing by surface contact between the exterior surface of the anchoring element and an interior surface of a heart lumen, preferably the atrium, wherein the closure element comprises an expandable scaffold structure, preferably an expandable stent structure, being covered by a porous sheath.

Description

Heart implant

Technical Field

The invention relates to a heart implant, particularly a heart implant being configured to reduce or eliminate a heart valve insufficiency after implantation into the heart.

Background of the invention

Typically, such implants are positioned in such a way that a closure element of the implant is situated in the valve annulus and closes a remaining gap of the closed valve leaflets. For that purpose, the closure element is connected to an anchoring element being configured to fix the closure element within the heart in the desired position i.e. in the valve annulus preferably to be contacted by the closing valve leaflets.

It is known in the art to use an anchoring element punctured into the myocardium of the ventricle for fixation of the closure element. Besides this invasive way modern implants provide a less invasive fixation just by contacting the interior wall of the atrium and/or the ventricle with the outer surface areas of an anchoring element formed of an expanded cage that is connected to the closure element. Anchoring elements, particularly the ones formed as a cage may be attached to the closure element on the atrial and/or ventricular side, most preferred only on the atrial side of the closure element. Such cage and closure element typically is in a collapsed state for feeding the entire implant through a catheter into the heart where it is expanded after release from the catheter for fixation purposes.

The invention generally relates to implants having an expandable closure element, no matter how the anchoring element is realized and preferably the invention relates to implants having an expandable closure element attached to an anchoring element formed as a cage of several strips, preferably interconnected strips forming a mesh. A cage may also be formed without meshes, particularly just by several side-by-side-lying strips having no interconnection. The invention in general also relates to non-meshed cages.

Applicants own patent applications having the serial numbers DE 10 2015 005 934.3 and EP 16000475.0 already disclose a heart implant comprising a tubular attachment element for attaching a sheath to it. In these documents the sheath is formed of an inflatable membrane. After attaching, particular fluid tight attaching an inflatable membrane that may be inflated by a liquid the expanded membrane and the tubular attachment element surrounded, preferably coaxially surrounded by the membrane form the aforementioned closure element that is to be positioned in the respective heart valve annulus. The membrane may be made of a flexible or elastic material, preferably a foil. An expanded membrane encircles a space surrounding the tubular attachment element that reduces or eliminates a gap between the leaflets.

The long term durability and resistance to leakage of such fluid-tight tillable closure elements is still to be proven.

Accordingly, it is an object of the invention to provide an implant having a closure element and at least one anchoring element attached to it preferably at least at the atrial side of the closure element that provides for the closure element the necessary long term durability, no problems with possible leakage and a smooth surface for harmless coaptation between this surface and the closing valve leaflet, preferably of the mitral valve.

Any direction mentioned in this application text is to be understood in relation to the implant correctly implanted in the heart, preferably if the closure element is positioned in the valve annulus, preferably of the mitral valve.

Even though the application of the implant is preferred in regard to humans the implant may be also applied to animals, particularly mammalian animals.

Summary of the invention

The object is solved by a heart implant, particularly being configured to reduce or eliminate a heart valve insufficiency after implantation into the heart, comprising a closure element being positionable within the heart valve annulus, particularly being configured to close or at least to reduce a remaining gap between closing valve leaflets, an anchoring element being attached to the closure element for fixing the implant in the heart, preferably for non-invasive fixing by surface contact between the exterior surface of the anchoring element and an interior surface of a heart lumen, preferably the atrium, wherein the closure element comprises an expandable scaffold structure, preferably an expandable stent structure, being covered by a porous sheath.

A stent structure is understood to be a meshed tubular element, the meshes preferably formed of interconnected struts or wires, particularly made of metal. Such meshed tubular element may be formed by stretching/expanding an axially slotted tube.

In addition to the scaffold structure a preferred embodiment also comprises at least one anchoring element attached to the closure element, that is also expandable, preferably after releasing the implant out of a delivery catheter. Such anchoring element preferably forms a cage as mentioned before. Particularly the cage is expanded to a bigger cross section compared to the scaffold structure of the closure element and provides a compliance / compressibility at least in a radial direction in relation to the longitudinal axis of the closure element in order to provide a force directed towards the myocardium of the lumen (e.g. atrium) in which it is positioned. The non-compressed cross section of such cage is at least slightly larger than the cross section of the lumen.

The features of the invention may provide different advantages. The particularly resilient scaffold structure underneath the porous sheath provides a long term resistance against cyclic force loading by the blood pressure changes and the coapting leaflets. The porous sheath at least provides a surface structure that promotes endothelialisation, particularly if the porous sheath furthermore

comprises an agent for promoting the endothelialisation. At least after

endothelialisation coaptation between the leaflets and the surface of the porous sheath is completely harmless.

According to a preferred embodiment the porous sheath is formed of a flexible membrane being unfoldable / stretchable by the expandable scaffold structure. Consequently, the porous sheath may cover a compressed scaffold structure during the implantation procedure and may be unfolded simultaneously together with the expanding scaffold structure. Expanding of the scaffold structure and preferably also of the at least one anchoring element may preferably automatically take place after release from a catheter, for example if the scaffold structure is made of a shape memory material like nitinol. In such embodiment the sheath may form a cover of the scaffold structure that tightly fits the scaffold surface.

In a furthermore preferred embodiment at least a part of the pores of the porous sheath are configured to allow blood to pass through the pores into the interior volume of the unfolded sheath. In this embodiment the sheath encircles a hollow space that may be filled with blood, preferably automatically if the scaffold expands and unfolds the supported sheath. Unfolding the sheath expands the inner encircled volume and blood may be sucked into this volume through the mentioned pores.

In an improvement of this embodiment the pores are furthermore restricted to a maximum size in order to prevent clotted blood from escaping out of the inner volume of the expanded sheath. Preferably the pores of the sheath have a cross section being less than 400 Micrometer, preferably less than 200 Micrometer, preferably less than 100 Micrometer. Embolism may be prevented this way.

Clotting of blood that entered the inner volume of the sheath may take and effects a filling of the inner volume thus providing further stabilization of the scaffold and the sheath spanned on top of it.

In a preferred embodiment the closure element comprises means for effecting different blood clotting rates in the internal volume of the closure element at the atrial and ventricular ends of the closure element, preferably for effecting blood clotting at a higher rate at the atrially disposed end of the closure element compared to the blood clotting rate at the ventricularly disposed end of the closure element.

Such different rates may be provided by a clotting effecting or at least enhancing means that is disposed / fixed in the internal volume of the closure element, particularly disposed near to the atrial side of the closure element. Such a means may be formed of at least one of the following: a mesh, particularly made of metal or plastic, a web, particularly made of metal or plastic, a foam or a thrombogenic material, preferably fibrinogen.

Furthermore, a means for generally effecting or promoting clotting in the inner space of the sheath may be a free floating means disposed in the internal volume of the closure element. Such means may be formed of the same

elements/materials as mentioned before. According to another embodiment, that may also be combined with the aforementioned embodiment the porosity of the sheath may be chosen to be different in different locations of the sheath surface, particularly the porosity is varying along the length of the closure element. The length being regarded in the direction of an imaginary connection line between atrium and ventricle passing preferably centrally through the closure element, when the implant is placed in the heart.

According to this embodiment the clotting rate may be locally controlled by the different porosities, particularly a higher clotting rate will be established at locations having a smaller porosity compared to locations having a higher porosity. This way the manufacture may control the locations in the closure element where clotting starts after implantation.

Accordingly, the different porosities may form a means of the closure element to effect the different clotting rates.

In a preferred improvement the porosity of the sheath is decreasing from one end of the closure element towards the opposite end of the closure element, preferably is decreasing from the end at the ventricular side of the closure body towards the end at the atrial side of the closure body. This provides that clotting starts or is promoted at the atrial side of the closure element. For example, the sheath may also have no porosity at the atrial side, i.e. a closed surface area facing the atrium.

The lower or no porosity at the atrial side provides a reduction of leakage through the closure element during ventricular systole and thus reduces mitral

regurgitation. The higher porosity at the ventricular side allows for easy filling the closure element through the sheath during systole and to replenish the closure element in the early phases when the porous membrane still leaks due to blood flow and loads due to leaflet coaptation.

The effect of these different embodiment is that the porous sheath at the atrial side becomes fully covered with clotted blood from the inside and leak proof first. The clotting progresses towards the ventricular side of the closure element until the porous sheath is also covered with clotted blood at the ventricular side. At the final stage the entire inner space of the closure element that is encircled by the porous membrane is filled with clotted blood. Afterwards the outer surface of the sheath is fully endothelialized.

The different porosities in different locations of the sheath surface may be provided by different cross sections of the pores and / or different numbers of pores per surface unit.

In a further improvement the internal volume of the sheath may comprise a material that is capable to swell due to blood contact, preferably the material being formed of a hydrogel. This improvement may be realized in combination with the aforementioned embodiments. The inner volume is accordingly filled with a combination of clotted blood and swollen material. Such an embodiment may speed up the filling of the closure element.

In all of the afore-mentioned embodiments the porous sheath may be formed of at least one of the following: a textile, preferably a woven, knitted or braided textile, furthermore preferred the textile being made of PET fibers or a surface coating of the scaffold being deposited to the scaffold by means of electrospinning a material solution or material melt, preferably of a polymer or a foil having holes or channels passing through the foil in the direction of the thickness of the foil. In a preferred embodiment the sheath may be formed of a textile being available at the market under the tradename DACRON.

In all the embodiments mentioned before it does not matter how the anchoring element is established but in a preferred embodiment the anchoring element is formed of an expandable cage comprising several strips, particularly

interconnected strips, the cage being positioned adjacent at least one of the two opposite ends of the scaffold structure / closure element, preferably on the atrial side of the closure element. In a possible embodiment the cage may be connected to the scaffold structure directly or via an openable link at a tapered part of the scaffold structure, the tapered part having a smaller cross section regarded perpendicular to the imaginary longitudinal axis of the closure element extending between atrium and ventricle compared to the part of the closure element to which the leaflets coapt.

Such tapered part may be formed of a tubular part, preferably a residual tubular part of the tube of which the scaffold structure and/or the anchoring cage are manufactured, preferably by tube slotting and expanding the tube. Such a tapered part of the scaffold structure / a residual tubular part may also or only exist on the ventricular side of the scaffold structure.

According to another possible embodiment at least a part of the strips of the anchoring cage are merging directly or via an openable link into strips that form the scaffold structure of the closure element. In a direction towards the cage the scaffold structure may be expanding in cross section regarded perpendicular to the imaginary longitudinal axis of the closure element and go over into the anchoring cage.

In all the mentioned embodiments the expandable scaffold structure and the expandable cage of the anchoring element may be formed of the same tube, preferably by means of laser cutting the tube surface and expanding the tube.

Also in all embodiments, as particularly mentioned at the end opposite the anchoring element the scaffold structure may be tapered and merge into a tubular element, preferably a tubular residual part as explained, the tubular element forming a connector for connecting a handling device. Such handling device may serve to place the implant at the correct position and/or to move it through a catheter.

At the end opposite the anchoring element the strips, particularly free tips of the strips, particularly of two connected strips that form the scaffold structure may be bent towards a central longitudinal axis of the scaffold structure. This provides a tapered ventricular end of the scaffold structure. At the end opposite the anchoring element the free tips of the strips, particularly of two connected strips that form the scaffold structure may also comprise pinholes. The pinholes may serve to connect sutures passing through a catheter or sutures fixing the sheath to the scaffold at this end.

In all embodiments the anchoring element may be at least partially covered with a porous membrane, preferably a textile membrane, preferably at least at the end of the anchoring element opposite the scaffold structure. Such membrane may be formed of the same material as the sheath of the closure element. The membrane may cover free tip ends of strips forming the anchoring cage and may prevent puncturing the myocard during implantation when the implant is not yet expanded and/or may promote tissue ingrowth and thus fixation of the anchoring cage. The membrane may have an annular shape and/or may be connected to the free tips of the strips that form the cage by at least one suture element passing through pinholes in the mentioned tips.

In all embodiment the porous sheath of the closure element may comprise two parts, namely a ventricular part covering a ventricular area of the scaffold structure and an atrial part covering an atrial area of the scaffold structure, the two part being connected, preferably by sewing or gluing. In the connection area the strips that connect the anchoring cage and the scaffold structure may pass through the sheath.

In the afore-mentioned embodiment according to which the scaffold structure has on both sides (atrial and ventricular) tapered tubular parts, particular residual tubular parts of the original tube of which the implant is manufactured, the sheath may be formed of a hose being connected to the tapered part at its respective ends. In this case the tapered tubular part at the atrial side has a closed cross section. Description of the figures

Figure 1 A, B, C illustrates the different states of clotting of the internal volume of the closure element

Figure 2A, B, C illustrate a first embodiment of the implant

Figure 3 illustrate a second embodiment of the implant

Figure 4A, B illustrate a third embodiment of the implant

Detailed description of the invention

Figure 1 schematically illustrates the effect of the inventive closure element 1 placed in the annular mitral valve of the heart 2. An anchoring element is not shown here but existing according to the following figures of the implant. The sheath covering a not shown scaffold structure that is connected to the not shown anchoring element has a higher porosity at the ventricular side V compared to the porosity at the atrial side A.

According to Figure 1A in the initial stage blood may pass through the sheath into the inner volume of the closure element 1 on the ventricular side when the leaflets 3 have coapted the sheath of the closure element 1 during ventricular systole. During diastole blood may exit the inner volume and may also bypass the closure element.

According to figure 1 B in an intermediary stage clotting of blood starts in the inner volume of the closure element 1 at the inner surface of the porous sheath predominantly at the atrial side A due to the lower porosity at this side. The clotting at this side stop the leakage of the sheath at this side but blood may still enter during systole and exit the inner volume of the closure element 1 at the opposite ventricular side V during diastole. In the final stage shown in figure 1 C clotting has taken place in the entire inner volume of the closure element that is covered by the sheath. Accordingly, leakage is prevented on atrial side A and ventricular side V. Regurgitation is thus prevented during systole and blood may only bypass the closure element during diastole.

Figures 2 show a first embodiment of the implant. Figure 2A shows a cross sectional view of the expanded implant, having the scaffold 4 of the closure element 1 and the anchoring cage 5 being covered by textile sheaths 6 and 7. Figure 2B just shows in a perspective view the scaffold 4 of the closure element 1 and the anchoring cage 5 in expanded state.

According to Figure 2A the sheath 6 that covers the scaffold 4 encircles an inner volume. The strips 8, that connect the scaffold 4 and the anchoring cage 5 are passing through the sheath at the atrial side A.

The sheath has a higher porosity at the ventricular side V compared to a lower porosity at the atrial side A. The different porosities are illustrated by different hatching. The porosity may continuously change along the longitudinal axis 9 or may have a stepped change. According to the lower porosity at the atrial side of the sheath clotting will predominantly will take place and/or start at this side providing the effect described before.

Figure 2C depicts that the sheath may be formed of two parts, a ventricular part 6a and an atrial part 6b, both being connected along a connection line 6c, particular by means of sewing. Accordingly, in a first step of production the ventricular part may be moved over the ventricular part of scaffold and in a second step the atrial part of the sheath may be place in the interior of the cage 5 and connected to the ventricular part. The connecting strips 8 may pass through the sheath at the connection / sewing line 6c. These steps of production may be performed in a compressed state of the scaffold and cage or in the expanded state. For implantation the implant will be compressed after attaching the sheath if the mentioned production is done in the expanded state. Figure 2B shows the internal structure of the implant without sheaths. As can be see the scaffold 4 and the cage 5 are preferable made of the same original tube by means of slotting the tube lengthwise and expanding the tube. Accordingly strips forming the cage 5 merge into strips forming the scaffold structure of the closure element 1. In this embodiment a residual tubular part 10 at the ventricular end of the scaffold structure 4 remains. This tubular part may form a connector for connecting auxiliary devices.

The atrial tips 5a of the cage forming strips comprise pinholes for connecting the textile sheath 7 to them as shown in figure 2A.

Figure 3 just shows the internal structure of an implant according to a second embodiment. In contrast to figures 2 the ventricular end of the scaffold 4

comprises free tips of the scaffold forming strips that have respective pinhole, particularly for connecting the sheath to the pinholes or for connecting a suture element that passes through a catheter during implantation. The free tips are bent towards the imaginary longitudinal axis 9 of the implant. The tubular part 10 is accordingly missing here. The not shown porous sheath, particularly a ventricular part of it may be closed at its ventricular end. All other features as disclosed for figure 2 also apply to figure 3.

Figures 4 show again in a cross sectional view and a perspective view another embodiment of the implant. Here Figure 4B also shows the sheath 6 covering the scaffold 4. Again the sheath has different porosities depicted by different hatching, a lower porosity at the atrial side A and a higher at the ventricular side V.

The implant is preferably made of a tube by slotting and expanding. In this embodiment on both sides of the scaffold 4 a residual tubular part 10a / 10b remains. A hose-like porous sheath 6 is attached to the respective tubular part 10a/10b at the respective two ends.

Beside the tapered atrial and ventricular ends of the scaffold the scaffold may have the same construction as shown in the other figures. Furthermore, the anchoring cage differs by strips emerging from the atrial tubular part 10b and forming a tree-shaped structure.

Claims

Heart implant, particularly being configured to reduce or eliminate a heart valve insufficiency after implantation into the heart, comprising

a. a closure element being positionable within the heart valve annulus, particularly being configured to close or at least to reduce a remaining gap between closing valve leaflets,

b. an anchoring element being attached to the closure element for

fixing the implant in the heart, preferably for non-invasive fixing by surface contact between the exterior surface of the anchoring element and an interior surface of a heart lumen, preferably the atrium, wherein the closure element comprises an expandable scaffold structure, preferably an expandable stent structure, being covered by a porous sheath.

Heart implant according to claim 1 , wherein the porous sheath is formed of a flexible membrane being unfoldable / stretchable by the expandable scaffold structure.

Heart implant according to anyone of the preceding claims, wherein at least a part the pores of the porous sheath are configured to allow blood to pass through the pores into the interior volume of the unfolded sheath.

Heart implant according to anyone of the preceding claims, wherein the pores of the sheath have a cross section being less than 400 Micrometer, preferably less than 200 Micrometer, preferably less than 100 Micrometer.

5. Heart implant according to anyone of the preceding claims wherein the closure element comprises means for effecting different blood clotting rates in the internal volume of the closure element at the atrial and ventricular ends of the closure element, preferably for effecting blood clotting at a higher rate at the atrially disposed end of the closure element compared to the blood clotting rate at the ventricularly disposed end of the closure element.

6. Heart implant according to anyone of the preceding claims, wherein the porosity of the sheath is different in different locations of the sheath surface, particularly the porosity is varying along the length of the closure element, preferably said means of claim 5 being provided by the said different porosities.

7. Heart implant according to anyone of the preceding claims wherein the porosity of the sheath is decreasing from one end of the closure element towards the opposite end of the closure element, preferably is decreasing from the end at the ventricular side of the closure body towards the end at the atrial side of the closure body.

8. Heart implant according to anyone of the preceding claims wherein the sheath has no porosity at the atrial side.

9. Heart implant according to anyone of the preceding claims 5 to 8, wherein a different porosity in different locations of the sheath surface is provided by different cross sections of the pores and / or different numbers of pores per surface unit.

10. Heart implant according to anyone of the preceding claims 5 to 9, wherein a clotting effecting or at least enhancing means is disposed in the internal volume of the closure element, particularly disposed near to the atrial side of the closure element.

11.Heart implant according to claim 10, wherein the means is formed of at least one of the following:

a. a mesh, particularly made of metal or plastic,

b. a web, particularly made of metal or plastic,

c. a foam,

d. a thrombogenic material, preferably fibrinogen.

12. Heart implant according to anyone of the preceding claims, wherein in the internal volume of the sheath a material is disposed, that is capable to swell due to blood contact, preferably the material being formed of a hydrogel.

13. Heart implant according to anyone of the preceding claims, wherein the porous sheath is formed of at least one of the following: a. a textile, preferably a woven, knitted or braided textile, furthermore preferred the textile being made of PET fibers, b. a surface coating of the scaffold being deposited to the scaffold by means of electrospinning a material solution or material melt, preferably of a polymer, c. a foil having holes or channels passing through the foil in the

direction of the thickness of the foil.

14. Heart implant according to anyone of the preceding claims, wherein the outer surface of the porous sheath comprises an agent for promoting endothelialisation.

15. Heart implant according to anyone of the preceding claims, wherein the anchoring element is formed of an expandable cage comprising several strips, particularly interconnected strips, the cage being positioned adjacent at least one of the two opposite ends of the scaffold structure / closure element, preferably on the atrial side and at least a part of these strips merging directly or via an openable link into strips that form the scaffold structure of the closure element.

16. Heart implant according to anyone of the preceding claims, wherein the expandable scaffold structure and the expandable cage of the anchoring element are formed of the same tube, preferably by means of laser cutting.

17. Heart implant according to anyone of the preceding claims, wherein at the end opposite the anchoring element the scaffold structure is tapered and merges into a tubular element, preferably the tubular element forming a connector for connecting a handling device.

18. Heart implant according to anyone of the preceding claims, wherein at the end opposite the anchoring element the free tips of the strips, particularly of two connected strips that form the scaffold structure are bent towards a central longitudinal axis of the scaffold structure.

19. Heart implant according to anyone of the preceding claims, wherein at the end opposite the anchoring element the free tips of the strips, particularly of two connected strips that form the scaffold structure comprise pinholes.

20. Heart implant according to anyone of the preceding claims, wherein the anchoring element is at least partially covered with a porous membrane, preferably a textile membrane, preferably at least at the end of the anchoring element opposite the scaffold structure.

2 . Heart implant according to anyone of the preceding claims, wherein the porous sheath comprises two parts, namely a ventricular part covering a ventricular area of the scaffold structure and an atrial part covering an atrial area of the scaffold structure, the two parts being connected, preferably by sewing or gluing.