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 (for example mitral or tricuspid valve) and closes a remaining gap of the closed valve leaflets. For that purpose, the closure element is connected to at least one anchoring element, for example an anchoring cage, 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.

In a possible embodiment disclosed in the applicants' own prior patent filings the closure element may be formed by an inflatable sheath / membrane that is positioned, preferably coaxially positioned around a central column element, preferably a tubular central column element and fixed to this element at the respective ends of the sheath / membrane to get a fluid tight space around the central column element. Such a fluid tight sheath may be inflated with a fluid. Preferably the areas of attaching the sheath to the central column element also define the upper and lower end of the closure element. In this embodiment the sheath forms a balloon that needs to be entirely filled with a fluid. Fluid tightness is one of the mayor problems with these embodiments since any leakage leads at least to a partial deflation of this balloon and accordingly to incompletely closing the gap between the leaflets.

In another embodiment disclosed in the applicants' own prior patent filings the closure element may be formed of a sheath/membrane being supported by an expanded part of a central column element, preferably tubular central column element. The expanded part may form a supporting structure, preferably a meshed supporting structure acting as a scaffold that supports the sheath from the inside.

By expanding the supporting structure also the sheath expands in cross section and contacts the underlying supporting structure formed by the expanded supporting element. The sheath also here prevents blood from passing through the valve in a closed leaflet state and may also be fluid tight.

The sheath of such a closure element is not necessarily fluid tight from the beginning of implantation. The sheath may have pores for allowing blood to enter the inner space of the closure element but may not allow clotted blood to escape from the inner space of the closure element. The blood may get clotted more and more with time and may close the sheath and thus form the closure element accordingly.

In this embodiment the supporting element forms a rigid scaffold lying under the surface that is contacted by the closing leaflets. Such a rigid supporting element is problematic in cases in which the correct position is not yet achieved prior to expansion of the supporting element since any correction would require the collapse of the supporting element.

In general and for the purpose of this invention the closure element is a plug that is configured to be positioned within the valve annulus of a valve that is to be treated. This plug will close or at least reduce a remaining gap between the closing leaflets of the valve.

It is known in the state of the art to use an anchoring element secured into the myocardium tissue of the ventricle for fixation of the closure element. Besides this invasive way, other implants provide a less invasive fixation just by contacting the interior wall of the atrium and/or ventricle with the outer surface areas of an anchoring element formed of an expanded cage that is connected to the closure element.

Such cage typically is crimped into a collapsed state for insertion of the entire implant through a catheter into the heart where it is expanded after release from the catheter for fixation purposes. The invention preferably relates to such implants having an expandable, particularly mesh-like anchoring cage formed of preferably interconnected strips for anchoring purposes.

An anchoring 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 and any other suitable anchoring element(s) attached to the closure element for fixation purposes, particularly for non-invasive fixation purposes.

In general and for the purpose of this invention an anchoring element is an anchor configured to fix the implant in the heart, preferably by surface contact only, i.e. without puncturing the myocard.

It is furthermore disclosed in the applicants' own prior patent filings that the central column element, preferably a tubular column element or tube has a lower end and an upper end and is split into several strips at least at the upper end, the strips forming an expandable cage as mentioned, particularly for fixing the heart implant to the atrium of the heart by surface contact between an exterior surface of the expandable cage (the several strips) and an interior atrium surface.

The mentioned positions "lower" and "upper" or directions mentioned in this disclosure are to be understood in the intended position of the implant if it is correctly implanted in the heart. In the heart the atrium is positioned above the ventricle and accordingly the lower end of the closure element faces the ventricle, particularly is positioned in the ventricle and the upper end faces the atrium, particularly is positioned in the atrium if correctly implanted. A middle part of the closure element between the upper and lower end is passing through the valve annulus of the valve that is to be treated, preferably the mitral or tricuspid valve.

The central column element, particularly the tubular central column element and the strips of an anchoring cage may originate from one single tube by cutting the tubular wall several times, preferably in an axial direction the mentioned strips all start their extension from an annular upper end area of the central column element and preferably are equally spaced along the circumference of this end. Such a cage may also be formed of strips starting their extension at the lower end of the central column element.

An anchoring element, particularly cage-like element is preferably formed by splitting and merging strips thus forming a half mesh between the points of splitting and merging. This embodiment is also preferred for the invention described in this disclosure.

An anchoring cage having several meshes is formed that way for solely fixing the heart implant to the atrium and/or ventricle of the heart by surface contact between the exterior cage surface and the interior surface of the respective heart lumen (atrium or ventricle). Preferably, the invention relates to an implant having a single anchoring cage only on the atrial side of the closure element.

A cage being formed of several expanded strips originating from a cut tube by radial expansion provides the advantage that the strips may generate a radial force being essentially perpendicular to the axis of extension of the (tubular) attachment element to keep the anchoring cage in place after implantation and expansion. The anchoring cage is sufficiently compliant in radial direction in order to adapt its shape to the atrium.

As mentioned above the closure elements known in the state of the art are problematic in regard to leakage or rigidity. Accordingly it is an object of the invention to improve existing heart implants and to provide an inventive implant having less problems in regard to leakage and better adjustability in regard to the position of the closure element within the valve annulus. Even though the application of the implant and the method are preferred in regards to humans the implant and method of treatment 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 configured to be positioned within the heart valve annulus, particularly being configured to close or at least to reduce a remaining gap between closing valve leaflets, the closure element comprising an expandable sheath, particularly a sheath to be contacted by coapting leaflets after

implantation, and an internal supporting structure supporting the sheath at the inner surface of the sheath, an anchoring element being attached to the closure element for fixing the implant in the heart, preferably for atraumatic 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 supporting structure is formed of at least one fluid fillable, preferably also expandable conduit structure.

It is one of the essential features of the invention to provide a supporting element for supporting the sheath from the inside of the sheath thus compensating any compression forces exerted to the sheath from the outside, for example by pressure differences during systole / diastole and by the contacting leaflets. But in contrast to the state of the art such a supporting element does not form a rigid scaffold or skeleton element, but a flexible one, particularly a flexible one at least during the beginning of an implantation process.

The supporting element formed as a conduit structure according to the invention is configured to be fillable with a fluid, for example a liquid and may be inflatable / expandable by the liquid. Accordingly the volume of the conduit structure may be dependent upon the pressure of the fluid in the conduit structure. This provides the advantage that the supporting element may have a compressed state for feeding the implant through a catheter and may have an expanded state for its use after implantation.

The capability to fill the conduit structure with a fluid creates a not rigid structure at least if the fluid maintains its fluidic, particularly liquid properties.

By using an implant according to the invention it is possible to expand the closure element by filling the conduit structure with a fluid. If the implant is not in a correct position the fluid may be simply removed or released from the conduit structure effecting that the closure element collapses again in order to reposition it and to fill again. This procedure may be repeated until the desired position is achieved.

In the preferred embodiment the system comprising the sheath and the at least one conduit is configured to expand into the desired pre-determined shape by filling the at least one conduit structure with a fluid, the conduit structure thus exerting an erecting force to the sheath from the inside of the sheath. This assures, that the closure element expands into the final shape and may be checked for correct position even if the filling with fluid is just for this positioning purpose and not the final itself.

According to the invention it is also possible to provide a rigid scaffold structure being an additional element to the conduit structure in the closure element that comes into effect once the correct position is found by inflating the conduit structure. The scaffold structure may be formed of a cut tubular central column element that gets expanded if the correct position is achieved and final.

Nonetheless, it is the preferred embodiment of the invention to avoid such an additional element and to make use of a conduit structure only that serves to define the final shape and that exerts the erecting force to the sheath of the closure element. Preferably it is an essential feature of the invention that the sheath is a passive element being influenced by the conduit structure to come into the final shape and the conduit structure is the only active element exerting the force for expanding the sheath. Preferably in this embodiment the sheath is spanning the conduit structure that exerts essentially radial outward directed forces.

It is a major advantage of the invention that the implant, particularly its conduit structure is configured to be filled with different fluids, particularly one after the other.

For that purpose in a preferred embodiment the at least one conduit structure comprises an inlet port and an outlet port, particularly both ports being separate to each other and spaced in the direction of a flow of fluid in the conduit, preferably the ports being positioned at the ventricular side of the closure element, preferably side by side or coaxially.

Preferably the flow of fluid is possible between the inlet port and the outlet port in a one-way direction only. Furthermore the conduit structure is designed such that no areas a stagnation of the fluid in the conduit structure is possible. Consequently any second fluid being urged into the inlet port will force the existing first fluid in the conduit to leave the conduit structure through the outlet port. Accordingly the entire conduit structure may be flushed and any existing fluid may be entirely replaced with another fluid.

Such an implant may be used in a system together with a filling device for filling a fluid into the conduit structure of the implant, wherein the system is configured to fill a first fluid, preferably saline solution, into the conduit in order to effect the expansion of the closure element and configured to flush the filled conduit structure with a second fluid, preferably a polymerizing fluid.

Using such a system a method of treating a heart valve insufficiency is possible by implanting an implant according to the invention into the heart, the implant comprising a closure element that is positioned within the heart valve annulus and being configured to close or at least to reduce a remaining gap between closing valve leaflets and comprising an anchoring element being attached to the closure element, the implant being fixed in the heart with the anchoring element, preferably by surface contact between the exterior surface of the anchoring element and an interior surface of a heart lumen, preferably the atrium, wherein after setting the implant into the desired place the conduit structure of the closure element is filled with a first fluid, preferably saline solution, via an inlet port of the conduit structure in order to effect the expansion of a sheath of the closure element and afterwards the conduit structure is flushed with a second fluid by filling the second fluid through the inlet port into the conduit structure and displacing the first fluid out of the outlet port of the conduit structure wherein the second fluid is formed of a polymerizing fluid that hardens and forms a rigid support of the sheath after hardening.

By using saline solution the closure element can be expanded into the final shape and its correct position may be checked. Preferably saline solution containing an x-ray contrast agent may be used to facilitate visualization under live x-ray images and therefore facilitating the evaluation of the positionning. In addition using a contrast agent also helps to check the fluid tightness of the conduit structure prior to the filling with another second fluid that is not allowed to come into contact with blood.

If the correct position is achieved using the first fluid, preferably saline solution, is exchanged by a second fluid that hardens after its application in the conduit structure. Such a second fluid is preferably formed by a polymerizing fluid. After hardening, the filled conduit structure forms a rigid scaffold or skeleton that supports the expanded sheath.

In a preferred embodiment of the implant the conduit structure may comprise at least one fluid tillable tubular channel, preferably several tubular channels, particularly branched of the at least one tubular channel. Such a tubular channel, preferably each tubular channel or its branched parts may have the same constant cross section along its entire extension. It may also have varying cross section along the extension, particularly the extension between inlet and outlet port. For example it may have bigger cross section at the upper and lower end of the closure element and a smaller one in between. Preferably the conduit structure may comprise a mesh of interconnected fluid fillable tubular channels. Such a conduit structure will form a mesh comparable to stents once it is filled with a hardened second fluid.

In another preferred embodiment the conduit structure comprises at least one helically wound tubular channel, preferably wound around the axial direction of the closure element. By filling the conduit structure the helical structure will tend to expand its diameter upon rising pressure, thus exerting primarily a radial force that expands the sheath.

It is also possible that the conduit structure comprises several tubular channels, each respective channel extending from a lowermost position of the closure element to an uppermost position of the closure element and the channels being spaced, preferably equally spaced in circumferential direction.

In all the mentioned and also not mentioned embodiments it is preferred that the at least one tubular channel of the at least one conduit structure is attached to the inner surface of the sheath. In this embodiment the at least one conduit structure may be formed of at least one separate tubular hollow element, particularly a flexible tube or hose that is attached to the inside surface of the sheath. This means that the conduit structure has its own surface element, particularly a flexible membrane that is connected to the sheath, for example by fusion welding, gluing or any suitable process. It is also possible that the inner surface of the sheath forms a part of the conduit structure. This preferably means that the volume encircled by the conduit structure is confined in parts by the inner surface of the sheath.

It is also possible in all the mentioned embodiments having at least one tubular conduit structure, that the at least one tubular channel of the at least one conduit structure is positioned between an outer sheath and an inner sheath, both sheaths surrounding a central column element of the closure element, particularly to which the sheaths are attached. Furthermore it may be provided in all embodiments, particularly the ones having tubular elements that the internal surface area of the sheath is covered by the conduit structure by not more than 50%. It is also possible that the total volume of the conduit structure is less than 5% of the entire internal volume surrounded by the sheath.

In a different embodiment the at least one conduit structure is formed of an outer sheath, particularly the sheath contacting the coapting leaflets, and an inner sheath and the hollow space in between, the two sheaths being spaced and connected to each other in the direction of their spacing in several locations, preferably the locations being evenly distributed over the opposing sheath surfaces. Accordingly, in this embodiment the sheath itself forms part of the conduit structure as mentioned before. The hollow spaces between the two sheaths and the connections may form inflatable cushions.

In all the possible embodiments the closure element may comprise a central column element to which the at least one sheath is fluid tight attached. This central column element may be flexible, particularly by means of several cuts in the surface area of the column element, that is preferably formed of a tube. The mentioned inlet and outlet ports of the conduit structure may be positioned in the lower end area of the column element, particularly the end area facing the ventricle. In such a construction these ports are easily accessible by a catheter, particularly the one of which the implant is released. In general at least one of the the ports or at least one of several tubular element of the conduit structure may comprise an valve element, for sealing the conduit structure, particularly a check valve, defining the flow direction in the conduit structure.

A valve in the inlet port may be actuated by pushing a catheter tip into the valve. A valve in the outlet port may be pressure actuated, particularly switched to an open state upon exceeding a threshold pressure in the conduit structure. The same central column element may be split into several strips forming the anchoring cage at the end area of the column element facing the atrium

The cage may be formed as disclosed in the introductory part.

Description of the drawings

Figure 1 : shows a single tubular channel prior to filling

Figure 2: shows the same tubular channel partly filled

Figure 3: shows the same tubular channel entirely filled with a fluid

Figure 4: depicts the exchange of the fluid by another fluid

Figure 5: Shows the completed fluid exchange

Figure 6: shows the fully hardened fluid in the tubular channel forming a rigid supporting structure

Figure 7: shows a compressed closure element with several deflated channels

Figure 8: shows an expanded closure element with an inflated helical channel

Figure 9: shows an inlet port construction of a channel

Detailed description of the drawings

The figures 1 to 6 depict several stages during the expansion process of a single channel 1 for the entire conduit structure or at least a part of it. The shown channel 1 is connected to the inside surface of a sheath that surrounds a central column element. Sheath and column element are not shown.

In the first stage of Figure 1 the channel 1 is deflated, particularly totally empty. Accordingly, it has a minimum cross section as needed during the process of feeding the implant through a catheter.

After implantation and setting the implant in the desired place the channel 1 is filled with a first fluid, preferably saline solution, as shown in Figure 2. Starting at the inlet port 2 the channel 1 gets inflated and expands in cross section. Any residual fluid is discharged out of the outlet port 3.

Figure 3 shows a situation in which the entire channel 1 between inlet port 2 and outlet port 3 is filled with the first fluid. Due to the fluid characteristics the channel remains flexible. The position of the closure element may be changed and corrected if needed.

Once the optimal position is achieved, the first fluid is replaced by a second fluid, this fluid being symbolized by a cross hatching in Figure 4. The second fluid starts entering the channel at the inlet port 2 and urges the first fluid to leave the channel 1 at the outlet port.

Inlet and outlet ports are connected to a catheter, accordingly the discharged fluid will remain in a closed system and cannot contaminate blood.

Figure 5 shows a situation in which the entire internal volume of the channel 1 is filled with the second fluid, preferably a polymer. Figure 6 shows the polymer in a hardened state, symbolized by the solid black line of the channel. Now the channel 1 forms a rigid supporting element for the sheath.

Figure 7 shows an entire closure element 4 in the compressed / deflated state. At the inside of the sheath several channels 1 are connected to the sheath. In this embodiment the several channels form a deflated mesh-like conduit structure. Any further internal column element is not shown.

The closure element 4 of Figure 7 may be inflated as described in Figures 1 to 6.

Figure 8 shows an inflated closure element 4, having a sheath 5 surrounding an internal central column element 6. The inlet port 2 and outlet port 3 may be accessible near the lower ventricular end of the central column element 6 or in its internal cross section at this position.

At the upper atrial end the column element 6 splits into several strips 7 that form an expanded anchoring cage. The strips 7 extend away from the column element 6 and are bent back to it, particularly by at least 180 degrees, near the top of the atrium.

Such kind of construction of the anchoring cage may be realized also in all the other embodiments even though it is not shown there.

In this specific embodiment the conduit structure is formed of at least one, preferably exact one tubular channel 1 having a helical extension along the inner surface of the sheath 5. Once the channel is inflated, it exerts an erecting force on the sheath thus forming the expanded closure element. The channel will be filled as described in Figures 1 to 6.

Figure 9 shows the specific construction of the inlet port 2. In this embodiment it comprises a valve 8 for closing the inlet port 2 unless it is entered by a catheter tip 9. Once the valve 8 is pushed open the first or second fluid may be fed to the channel 1 as described in Figures 1 to 6.

The outlet port may also have a (similar) valve construction that keeps the outlet port closed unless a threshold pressure is exceeded. This helps to maintain a necessary pressure in the channel to keep it inflated and to facilitate the exchange of the first fluid by bringing the second fluid into the inlet port with the necessary pressure to open the valve of the outlet port.