IMPLANT WITH A HOLLOW CYLINDER-SHAPED AND LUMEN-DEFINING STENT BODY

Abstract

The invention relates to an implant with a hollow cylindrical stent body defining a lumen, to which at least one functional arm movable relative to the stent body is attached, wherein the at least one functional arm has a first configuration in which the at least one functional arm and at least one end region of the at least one functional arm are oriented at least substantially luminally with respect to the lumen of the stent body, and a second configuration in which the at least one functional arm and at least the end region of the at least one functional arm are oriented at least substantially abluminally with respect to the lumen of the stent body.

Description

The present invention relates generally to the field of medical technology and in particular to an implant with at least one functional component which, in the implanted state of the implant, serves to encompass, clamp or otherwise contact body or foreign structures. For example, the implant serves to support and keep open a blood vessel, for example in the fields of urology or neurology. Another application of the implant is the treatment of an inflamed and / or infected heart valve. In this case, the implant is suitable for creating a compartmentalized area, at least in part, to compartmentalize the infected tissue of the heart valve being treated. Specifically, the implant according to the invention comprises a hollow cylindrical stent body that defines a lumen. At least one functional arm, movable relative to the stent body, is attached to the stent body. The at least one functional arm has a first configuration in which the at least one functional arm and at least one end region of the at least one functional arm are oriented at least substantially luminally with respect to the lumen of the stent body. The at least one functional arm further has a second configuration in which the at least one functional arm is oriented at least substantially abluminally with respect to the lumen of the stent body. In embodiments, the first and second configurations are reversed; that is, the at least one functional arm has a first configuration in which the at least one functional arm and at least one end region of the at least one functional arm are oriented at least substantially abluminally with respect to the lumen of the stent body. In these embodiments, the at least one functional arm further has a second configuration in which the at least one functional arm is oriented at least substantially luminally with respect to the lumen of the stent body. In particular, according to the invention, it is provided that at least the at least one functional arm is / are at least partially or partially formed, and preferably both the at least one functional arm and the stent body of the implant are at least partially or partially formed from a shape memory material, in particular from a nickel-titanium alloy. However, the invention is not limited to a nickel-titanium alloy. Rather, a polymer plastic can also be used as a shape-memory material. Shape-memory polymers belong to the group of intelligent polymers and are polymers that exhibit a shape-memory effect, i.e., they can change their external shape under the influence of an external stimulus, such as a temperature change. In this process, the polymer is first formed into its permanent shape using conventional processing methods such as injection molding or extrusion. The plastic is then deformed and fixed in the desired temporary shape, a process also known as "programming." With polymers, this can be achieved by heating the sample, deforming it, and then cooling it. Alternatively, the polymer can be deformed at a low temperature, a process known as "cold stretching." In this case, the permanent shape is stored, while the temporary shape is in effect. If the polymer mold is then heated to a temperature higher than the switching temperature, the shape memory effect is triggered, restoring the stored, permanent shape. Cooling the sample does not revert the temporary shape, which is why it is referred to as a one-way shape memory effect. Compared to nickel-titanium alloys, shape memory polymers offer significantly superior shape memory performance. Only minimal effort (heating or cooling) is required to program the temporary shape or restore the permanent shape. Furthermore, the maximum reversible deformation without permanent deformation between the permanent and temporary shapes is only about 8% for nickel-titanium alloys. Shape memory polymers exhibit considerably higher deformability of up to 1,100%. On the other hand, nickel-titanium alloys offer long-term stability in load-bearing components of implants and exhibit relatively good biocompatibility and stability. In principle, it is also conceivable that the implant or stent body, with at least one functional arm, is made of a biodegradable shape-memory material, and in particular of a biodegradable shape-memory polymer material. Synthetic, biodegradable implant materials are especially suitable. Such biodegradable materials or polymers contain bonds that can be cleaved under physiological conditions. The term "biodegradability" is used when the material degrades through or within a biological system, resulting in a loss of its mechanical properties. The external shape and mass of the implant may remain intact during degradation. When a degradation time is mentioned without further quantitative specification, it refers to the time until the complete loss of mechanical properties occurs. Biostable materials are those that are stable in biological systems and are at least partially degraded in the long term. Among biodegradable polymers, a distinction can be made between enzyme-free, hydrolytically degradable, and enzymatically degradable polymers. Enzyme-free hydrolytic degradation can occur virtually anywhere in the presence of water and is generally influenced by the surrounding chemical environment (especially pH) and physical environment (especially temperature). In contrast, the concentration of enzymes varies considerably from place to place. Therefore, biodegradable polymers or materials can degrade through pure hydrolysis, enzymatically induced reactions, or combinations thereof. Typical hydrolyzable chemical bonds in polymer compounds are amide, ester, anhydride, or acetal bonds. Two mechanisms are observed during degradation. In surface degradation, the hydrolysis of chemical bonds occurs exclusively at the surface. Due to the hydrophobic nature of some polymers, polymer degradation at the surface occurs faster than the diffusion of water into the interior of the material. This mechanism is observed primarily in poly(anhydrides) or polyesters. For polyhydroxycarboxylic acids, such as polylactic acid or polyglycolic acid, or corresponding copolymers, which are particularly important for the shape memory effect, polymer degradation occurs throughout the entire volume. The rate-limiting step here is hydrolytic bond cleavage, since the diffusion of water in the rather hydrophilic polymer matrix occurs relatively quickly.For the application of biodegradable polymers, it is crucial that they degrade at a controllable or adjustable rate and that the degradation products are non-toxic. According to implementations of the implant according to the invention, it is provided that the at least one functional arm has at least one such elastically designed folding area that, via this folding area, the at least one functional arm and at least the end area of ​​the at least one functional arm can be elastically transferred from its first shape (= imprinting the shape that is sought by the material after exceeding the transition temperature) to its second shape and vice versa. Alternatively or in addition to such a folding area, it is also conceivable that the at least one functional arm has at least one torsion area, wherein a torsional movement preferably by 180° takes place simultaneously when the at least one functional arm is transferred from its first shape to its second shape (and vice versa). As already explained, it is advantageous that at least one functional arm is formed at least partially or in sections from a shape memory material, in particular a shape memory polymer or a nickel-titanium alloy. The initial shape of the functional arm is imprinted during the programming of the implant during its manufacture. In particular, during the manufacturing of the implant, the at least one functional arm is guided into the lumen of the stent body in a shaping step and, after the shaping step, is guided out of the lumen of the stent body again to the outside, so that the at least one functional arm of the implant has a restoring force from the outside to the inside. Alternatively, it is also conceivable that the at least one functional arm is led outwards from the lumen of the stent body during the manufacturing of the implant in a shaping step and is led back into the lumen of the stent body after the shaping step, so that the at least one functional arm of the implant has a restoring force from the inside out. Preferred embodiments of the implant have a first state in which the implant, preferably in a radially compressed form at least partially or in certain areas, can be inserted minimally invasively into a patient's body using an insertion catheter system. From the first state, the implant can be transferred to a second state in which the implant is present in the implanted state at the implantation site in the patient's body (preferably in a radially expanded form at least partially or in certain areas). In the first state of the implant, the at least one functional arm has any shape that is useful or advantageous for insertion (e.g.,In the first state, the implant (folded upwards or bent to allow insertion into a diameter-limited delivery catheter) is positioned so that at least one functional arm attempts to achieve its initial shape, but cannot do so due to contact with other parts of the implant. Because the initial shape cannot be fully achieved by restoring force due to this contact, a restoring force remains, resulting in the at least one functional arm being pressed against another part of the implant. This pressure can be used to grasp, compose, or compartmentalize tissue or other structures. In particular, at least one functional arm is designed to be self-aligning in such a way that, during implantation of the implant, it independently strives to achieve its first shape based on its shape present at the time of implantation (e.g. in the catheter). According to preferred embodiments of the implant according to the invention, the at least one functional arm is designed to clamp and hold a structure between at least the end region of the at least one functional arm and an inner wall region of the lumen of the stent body during the implantation of the implant and during the transition of the at least one functional arm towards its first shaping. The structure in question is specifically a structure inherent to the patient's own body. This includes, for example, a section of a heart valve or a heart valve leaflet, particularly with superimposed or adhering structures of the patient's own body, such as blood clots or calcifications. Alternatively, foreign structures are also possible, especially biofilms or infectious vegetations. For example, it is conceivable that at least one functional arm is formed, during the implantation of the implant and during the transition towards its initial shaping, together with an inner wall area of ​​the lumen of the stent body, to form a compartmentalization area for compartmentalizing an area of ​​a native heart valve or a native heart valve leaflet and / or for compartmentalizing infectious and / or thrombotic deposits and / or vegetations. In this context in particular, it is advantageous for at least one functional arm and / or the stent body of the implant to have / have a drug-releasing system, which is specifically designed as a drug-delivery system for the selective release of active substances in the implanted state of the implant. According to implementations of the implant according to the invention, the at least one functional arm is designed in a bow or arc shape and has two leg regions, wherein the at least one functional arm is connected to the stent body via a first end region of each of the two leg regions. The at least one functional arm is preferably integral with the stent body. The two leg areas of the at least one functional arm can be connected to each other via a rounded and, in particular, U- or V-shaped connection area. To create a compartmentalized area, a suitable separating structure can be used, such as a film, a fabric, and / or a membrane, which, together with the at least one functional arm, forms the compartmentalized area so that the compartmentalized area is more clearly separated from surrounding body fluids or tissues. The separating structure can be connected to the at least one functional arm. An exemplary embodiment of the implant according to the invention is described in more detail below with reference to the accompanying drawings. Figure 1 schematically shows an exemplary embodiment of the implant according to the invention, in which the functional arm of the implant is in its first configuration, i.e., is oriented at least substantially luminally with respect to the lumen of the stent body; Figure 2 schematically and in an isometric frontal view shows the exemplary embodiment of the implant according to the invention according to Figure 1; Figure 3 schematically and in an isometric side view shows the exemplary embodiment of the implant according to the invention according to Figure 1, but in a state in which the functional arm is in its second configuration, in which the functional arm is oriented at least substantially abluminally with respect to the lumen of the stent body; Figure 4 schematically and in an isometric frontal view shows the exemplary embodiment of the implant according to the invention according to Figure 3; Figure 4Fig. 5 schematically shows an exemplary embodiment of the implant according to the invention, in which the functional arm of the implant is in its first configuration, i.e., is oriented at least substantially abluminally with respect to the lumen of the stent body; Fig. 6 schematically and in an isometric frontal view shows the exemplary embodiment of the implant according to the invention according to Fig. 5; Fig. 7 schematically and in an isometric side view shows the exemplary embodiment of the implant according to the invention according to Fig. 5, but in a state in which the functional arm is in its second configuration, in which the functional arm is oriented at least substantially luminally with respect to the lumen of the stent body; and Fig. 8 schematically and in an isometric frontal view shows the exemplary embodiment of the implant according to the invention according to Fig. 7. Figures 1 and 2 each show a schematic, isometric view of an exemplary embodiment of the implant according to the invention in a state in which the functional arm of the implant is in its first configuration. In the first configuration, the functional arm of the implant, or at least an end region of the functional arm of the implant, is oriented at least substantially luminally with respect to a lumen of the stent body of the implant. In Fig. 3 and Fig. 4, however, the exemplary embodiment of the implant according to the invention is shown schematically and in an isometric view in a state in which the functional arm is in its second form, in which the functional arm of the implant and at least one end region of the functional arm of the implant is oriented at least substantially abluminally with regard to the lumen of the stent body. The implant comprises the aforementioned stent body. This is a hollow cylindrical stent body that defines a lumen. Additionally, the implant according to the invention, in the exemplary embodiment shown in the drawings, includes the functional arm also mentioned above, which is movably attached to the stent body relative to it. The implant, and in particular the functional arm of the implant, and preferably both the functional arm and the stent body of the implant, are at least partially or partially made of a shape memory material. This could be, for example, a nickel-titanium alloy. Of course, alternative shape memory materials are also conceivable, in particular a shape memory polymer. A shape memory polymer may be superior to the shape memory alloy "nickel-titanium" at least with regard to memory performance. Regardless of which shape memory material is used to form at least part or section of the functional arm of the implant according to the invention, the initial shaping of the functional arm is programmed accordingly during the implant's manufacture. Figures 1 and 2 show the state of the implant during the shaping process to produce the imprinted configuration of the functional arm. The imprinted configuration is one in which at least the end region of the functional arm is oriented within the lumen of the stent body, i.e., luminally. Figures 3 and 4 show the implant in its state after shaping and before actual implantation, with a modified configuration of the functional arm. In this configuration, the functional arm, and especially its end region, is essentially abluminally oriented with respect to the stent body lumen. In other words, the functional arm, which is movably connected to the stent body relative to it, lies outside the stent body lumen in the second shaping shown in Figures 3 and 4. This generates an active restoring force because it attempts to assume the programmed shape, but cannot achieve it, or cannot fully achieve it, due to the intervening part of the implant. In this context, it is conceivable that the functional arm has at least one such elastically designed folding and / or torsion area that, via this folding and / or torsion area, the functional arm and at least the end area of ​​the functional arm can be elastically transformed from its second shape shown in Fig. 3 and Fig. 4 into its first shape shown in Fig. 1 and Fig. 2 and vice versa. If, on the other hand, a torsion area designed to be particularly elastic is used, a luminal side or surface of the functional arm in the second shaping of the functional arm also forms a luminal side or surface of the functional arm in the first shaping of the functional arm. As can be seen from the drawings, the functional arm is designed in a bow or arc shape and has two leg sections, with the functional arm being connected to the stent body of the implant via a first end section of each of the two leg sections. The two leg sections of the functional arm are connected to each other via a rounded, and in particular U- or V-shaped, connecting area. The implant shown schematically in the drawings serves, in particular, to form a compartmentalized area in the implanted state, i.e., when the functional arm is in its initial configuration. Specifically, the functional arm is designed to clamp and hold a structure (not shown in the drawings) between at least the end region of the functional arm and an inner wall region of the stent body lumen during implantation and the transition to its initial configuration. This structure may in particular be a structure that is intrinsic to the patient's body, especially an area of ​​a heart valve or a heart valve leaflet, for example with superimposed or adhering intrinsic structures, especially blood clots or calcifications, or with foreign structures, especially biofilms or infectious vegetations. By forming a corresponding compartmentalized area, the structure can be compartmentalized accordingly. In this context, it is particularly conceivable that the functional arm and / or the stent body incorporates a drug-releasing system, which may be designed as a controlled-release drug delivery system and serves primarily to release active substances into the compartmentalized area in the implanted state. The invention is not limited to the embodiment of the implant shown in the drawings, but results from a combination of all the features disclosed herein.

Claims

Implant with a hollow cylindrical stent body defining a lumen, to which at least one functional arm movable relative to the stent body is attached, wherein the at least one functional arm has a first shape in which the at least one functional arm and at least one end region of the at least one functional arm are oriented at least substantially luminally with respect to the lumen of the stent body, and a second shape in which the at least one functional arm and at least the end region of the at least one functional arm are oriented at least substantially abluminally with respect to the lumen of the stent body. Implant according to claim 1, wherein at least the at least one functional arm is / are at least partially or partially and preferably both the at least one functional arm and the stent body are at least partially or partially made of a shape memory material, in particular a shape memory polymer or a nickel-titanium alloy. Implant according to claim 1 or 2, wherein the at least one functional arm has at least one such elastically or superelastically designed folding and / or torsion area that, via this folding and / or torsion area, the at least one functional arm and at least the end area of ​​the at least one functional arm can be elastically transferred from its first shape to its second shape and vice versa. Implant according to one of claims 1 to 3, wherein at least one functional arm is formed at least partially or in certain areas from a shape memory material, and wherein the first shape of the at least one functional arm was imprinted during the programming of the at least one functional arm during the manufacture of the implant. Implant according to one of claims 1 to 4, wherein the at least one functional arm is guided into the lumen of the stent body in a forming step during the manufacture of the implant and is guided outwards from the lumen of the stent body after the forming step, so that the at least one functional arm of the implant has a restoring force from the outside to the inside; or wherein the at least one functional arm is guided outwards from the lumen of the stent body in a forming step during the manufacture of the implant and is guided back into the lumen of the stent body after the forming step, so that the at least one functional arm of the implant has a restoring force from the inside to the outside. Implant according to one of claims 1 to 5, wherein the implant is transferable from a first state, in which the implant preferably exists in an at least partially or partially radially compressed form and is preferably minimally invasively insertable into the body of a patient via an insertion catheter system, to a second state, in which the implant is present in the implanted state at an implantation site in the body of the patient, wherein in the first state of the implant the at least one functional arm has a shape different from the first shape, and wherein in the second state of the implant the at least one functional arm attempts to return to its first shape. Implant according to one of claims 1 to 6, wherein the at least one functional arm is designed to be self-aligning such that, during implantation of the implant, the at least one functional arm independently attempts to return to its initial shape from its shape present during implantation of the implant. Implant according to claim 7, wherein in the implanted state of the implant the at least one functional arm is blocked in such a way that the at least one functional arm does not or at least not completely return to its initial shape, so that a restoring force remains. Implant according to one of claims 1 to 8, wherein the at least one functional arm is configured to clamp and hold a structure during the implantation of the implant and during the transition towards its first shaping between at least the end region of the at least one functional arm and an inner wall region of the lumen of the stent body. Implant according to claim 9, wherein the structure is a structure native to the patient, in particular a region of a heart valve or a heart valve leaflet, in particular with superimposed or adhering native structures, in particular blood clots or calcifications, or with foreign structures, in particular biofilms or infectious vegetations. Implant according to one of claims 1 to 9, wherein the at least one functional arm is designed, during the implantation of the implant and during the transition towards its first shaping, together with an inner wall area of ​​the lumen of the stent body, to form a compartmentalization area for compartmentalizing an area of ​​a native heart valve or a native heart valve leaflet and / or for compartmentalizing infectious and / or thrombotic deposits and / or vegetations. Implant according to one of claims 1 to 9, wherein the at least one functional arm is configured, during the implantation of the implant and during the transition towards its first shaping, together with an outer wall area of ​​the lumen of the stent body, to form a compartmentalization area for compartmentalizing an area of ​​a native heart valve or a native heart valve leaflet and / or for compartmentalizing infectious and / or thrombotic deposits and / or vegetations. Implants according to any one of claims 1 to 10, wherein the at least one functional arm comprises a drug-releasing system, which is in particular designed as a controlled-release drug delivery system for the selective and / or preferential release of active substances in the implanted state of the implant. Implant according to one of claims 1 to 13, wherein the at least one functional arm is designed in a bow or arc shape and has two leg regions, wherein the at least one functional arm is connected to the stent body via a first end region of each of the two leg regions, and wherein the two leg regions are preferably connected to each other via a rounded and in particular U- or V-shaped connecting region. Implant according to one of claims 1 to 14, wherein the at least one functional arm is integral with the stent body.

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