Patent Application
20220331098
A field of the invention is artificial cardiac valves.
Artificial cardiac valves are used to assist or replace tricuspid valve functionality or mitral valve functionality. Artificial cardiac valves are delivered to a treatment site via a delivery catheter. Manufacture of conventional artificial cardiac vales is typically complex and difficult.
WO 2017/147082 A1 describes a bifurcated tubular graft for treating tricuspid regurgitation. One leg of the bifurcated graft extends across the tricuspid valve. This leg includes in its interior a bioprosthetic valve that replaces the functionality of the tricuspid valve. The implantation of such a bifurcated graft is rather difficult and its method of manufacture is rather complex.
CN 206995366 U describes a stent for treating tricuspid regurgitation. This stent has an overall oblong shape and is placed with one end in the inferior vena cava and with its other end in the superior vena cava. It includes a central opening to be placed in the right atrium and allowing an unhindered blood flow into an interior of the stent and out of the interior of the stent. The stent furthermore includes two biological cardiac valves placed in the interior of the stent. These two biological valves allow a blood flow from the inferior vena cava and from the superior vena cava to the right atrium, but not in the opposite direction. To achieve correct positioning of the stent within the heart of the patient, it includes a plurality of radiopaque markers that mark the position of the central opening of the stent. The configuration of the above-described device appears to be rather complex.
CN 207253400 U also describes a stent assembly for the treatment of tricuspid regurgitation. This stent also has an overall oblong shape. It includes two grid-like cylindrical stents that are to be implanted into the inferior vena cava and into the superior vena cava. Between these two grid-like cylindrical stents, a connecting wire is provided that prevents a displacement of the cylindrical stents. The connecting wire does not limit a blood flow in the area in which it is positioned. In order to prevent an undesired blood flow from the right atrium into the inferior vena cava and the superior vena cava, both grid-like cylindrical stents include in each case a biological valve sewn to the respective stent. The configuration of the above-described device appears to be rather complex as well.
US 2018/0021130 A1 describes a tricuspid insufficiency treatment device including a vena cava member and that is implantable in a vena cava of a patient. Therein, the vena cava member is formed with a fenestration and further includes a blocking member arranged to block and unblock the fenestration.
The present invention provides an artificial cardiac valve that can assist or replace tricuspid valve functionality or mitral valve functionality and that can be more easily manufactured and/or more easily implanted than artificial cardiac valves discussed in the background. A preferred artificial heart valve includes support structure having a first end and second end and defining an interior of the valve. A covering covers the support structure and includes an intermediate portion with a plurality of intermediate strip-shaped sections having cuts between them. Some are attached to the stent and others are not so that a closed configuration prevents retrograde blood flow into an interior of the stent with the free strip-shaped sections abutting the stent and overlapping or abutting the attached strip-shaped sections to prevent retrograde blood flow into the interior. An open configuration is formed with the unattached strip-shaped sections lifting from the stent to allow antegrade blood flow from the interior of the stent.
Further details of aspects of the present invention will be explained with respect to exemplary embodiments and accompanying Figures. In the Figures:
An artificial cardiac valve includes a support structure and a covering, the covering at least partially enwrapping an outer side of the support structure, and wherein the covering includes a longitudinal opening, and wherein different sections of the covering are—due to the longitudinal opening—relatively movable to each other and either overlap or tightly adjoin to one another along the longitudinal opening, so that the covering can be present in two different configurations, an open and a closed configuration acting as a check valve.
The cardiac valve includes a support structure such as a hollow-cylindrical or tubular stent and a covering at least partially enwrapping an outer side of the support structure (e.g. stent). In one embodiment, the covering is enwrapping an outer side of the support structure (e.g. stent). The support structure, preferably being a hollow-cylindrical or tubular stent, has a first end area and a second end area, whereby the second end area is spaced apart from the first end area.
With the context of the present invention and throughout the description portion, the expression “support structure” may be interchangeably used with a “stent”, a “stent frame”, or, e.g., a “stent structure”, or vice versa. Preferably, the expressions “support structure” and “stent”, “stent frame”, “stent structure” relate in shape and nature to a hollow-cylindrical or tubular stent, stent frame or stent structure with the context of the invention.
In one embodiment of the invention, in view of the aforementioned “at least partially enwrapping of an outer side of the support structure”, the first end area and/or the second end area may be free of the covering.
In accordance with the invention, the support structure further has an intermediate area extending between the first end area and the second end area along the longitudinal axis (L) of the stent, whereby, the second end area is spaced apart from the first end area.
In one embodiment of the invention, the covering is connected to the support structure by at least one connection. The connection can be a fixed connection (e.g. a tight connection) or a loose connection, or a combination of both as the skilled person readily understands in dependence of whatever specifications of the artificial cardiac valve shall be met.
Thus, in an alternative embodiment of the invention, the covering is loosely attached to the support structure by at least one loose connection. With this context, “loosely attached” or the like means that the covering is not tightly connected over an entire length of the support structure.
The connection between the covering and the support structure can be realized, e.g., by sewing, gluing, suitable material embedding techniques, electrospinning or any other appropriate fixation methods known by the skilled artisan.
According to the present invention a suitable material embedding technique means that at least a part of the support structure is embedded in a part of the covering or in an extension thereof, so as to connect the covering to the support structure. Particularly, the covering is connected to the support structure in a sutureless (seamless) fashion. A part of the three-dimensional shape of the covering thereby deviates from the three-dimensional shape of the support element. The support element is not embedded in the part of the covering that deviates from the support structure. As a result, this part of the covering is free to move independently from the support structure and is therefore able to perform a valve function as disclosed herein. This is important, for example, for a heart valve implant in which at least a part of the covering with a longitudinal opening as functional element, i.e. the heart valve element, has to be able to flexibly open and close in response to antegrade and retrograde blood flow. Preferably, at least 10% of the three-dimensional shape of the covering deviates from the support structure, more preferably at least 20%, even more preferably at least 30%, yet more preferably at least 40% and most preferably at least 50%. The larger the part of the covering that deviates from the support structure, the more of the covering surface area can be used by the implant to perform a valve function that necessitates movement of the longitudinal opening that is independent of that of the support structure.
Preferably, the covering includes at least a part that is essentially made of (consists essentially of) bacterial cellulose. This part of the covering preferably has a part of the support structure embedded within so as to connect the covering to the support structure.
Following the above, in one embodiment of the invention the artificial cardiac valve includes:
wherein the three-dimensional shape of the covering at least in part deviates from the three-dimensional shape of the support structure, and wherein a part of the support structure is embedded in a part of the covering that includes bacterial cellulose so as to connect the covering to the support structure.
A structure that is essentially made of bacterial cellulose in the context of this disclosure refers to a structure that is made by deposition of bacterial cellulose on a given surface by a bacterium that produces bacterial cellulose. Such bacterial cellulose is usually of high purity and therefore the thus formed object essentially consists of bacterial cellulose. Bacterial cellulose that contains impurities or for example cellular debris from bacteria or entire bacteria that were incorporated during the deposition of the bacterial cellulose by the bacteria would still be counted in the context of this disclosure as bacterial cellulose that is essentially made of, or essentially consists of, bacterial cellulose.
The covering of the invention fluidly separates an interior of the support structure from an outer space or an outer side of the support structure. I.e., fluid such as blood being present in the support structure cannot flow from the interior towards the outside of the support structure (antegrade flow), as long as the covering does not provide an appropriate opening for such flow such as a longitudinal opening. Likewise, the flow of a fluid is not possible in the inverse direction from an outside into the interior of the support structure without an appropriate opening such as a longitudinal opening in the covering (retrograde flow).
In order to allow a fluid such as blood to enter the interior of the support structure, the first end area includes a first opening. Likewise, the second end area includes a second opening. Typically, the first opening and the second opening are provided in an axial terminus of the first end area and the second end area so that blood can enter into the interior of the stent along the longitudinal axis of the stent. However, other designs of the first opening and the second opening are also possible. Generally, the first opening and the second opening are not covered by the covering.
In one embodiment of the invention, the covering includes or is essentially made from at least one strip-shaped element substantially surrounding the support structure and being arranged in such a way that allows for the formation of a longitudinal opening. Thereby, the longitudinal opening extends from a first opening starting point to a first opening ending point. Thereby, the first opening starting point and the first opening ending point are spaced apart from each other along a longitudinal axis (L) of the support structure.
In one embodiment, the covering includes or is essentially made from at least one strip-shaped element having a longitudinal opening such as a gap or a cut, preferably a longitudinal gap or a longitudinal cut. Thereby, the longitudinal opening such as a gap or a cut extends from a first longitudinal opening starting point to a first longitudinal opening ending point. Thereby, the first longitudinal opening starting point and the first longitudinal opening ending point are spaced apart from each other along the longitudinal axis (L) of the support structure.
With the context of the present invention, the expression “longitudinal opening” denotes any form of opening that extends in a longitudinal direction. For instance, a longitudinal opening may be realized by the mere arrangement of at least two overlapping strip-shaped elements which form some sort of a gap in between when they are relatively movable to one another. Also, a cut in at least one strip-shaped element forms a longitudinal opening, whereby the cut may be realized by a straight line or in a curved manner. In certain instances with the context of the present invention, the skilled person clearly understands that the expressions “longitudinal opening”, “gap”, “cut”, and “opening” may be used interchangeably.
In one embodiment of the invention, the covering includes or is essentially made from at least two strip-shaped elements substantially surrounding the support structure and being arranged in such a way that allows for the formation of a longitudinal opening, preferably two longitudinal openings. Thereby, the longitudinal opening(s) extend(s) from a respective longitudinal opening starting point to a respective longitudinal opening ending point. Thereby, the respective longitudinal opening starting point and the respective longitudinal opening ending point are spaced apart from each other along a longitudinal axis (L) of the support structure.
In one embodiment, the covering includes or is essentially made from at least two strip-shaped elements having one or more longitudinal openings such as a cut, preferably one or more longitudinal cuts, most preferred two cuts. Thereby, the longitudinal opening(s) such as a cut extend(s) from a respective longitudinal opening starting point to a respective longitudinal opening ending point. Thereby, the respective longitudinal opening starting point and the respective longitudinal opening ending point are spaced apart from each other along the longitudinal axis (L) of the support structure.
In one embodiment of the invention, the covering includes or is essentially made from at least four strip-shaped elements substantially surrounding the support structure and being arranged in such a way that allows for the formation of a longitudinal opening, preferably two longitudinal openings, more preferably four longitudinal openings. Thereby, the longitudinal opening(s) extend(s) from a respective longitudinal opening starting point to a respective longitudinal opening ending point. Thereby, the respective longitudinal opening starting point and the respective longitudinal opening ending point are spaced apart from each other along a longitudinal axis (L) of the support structure.
In one embodiment, the covering includes or is essentially made from at least four strip-shaped elements having one or more longitudinal openings such as a cut, preferably one or more longitudinal cuts, most preferred four cuts. Thereby, the longitudinal opening(s) such as a cut extend(s) from a respective longitudinal opening starting point to a respective longitudinal opening ending point. Thereby, the respective longitudinal opening starting point and the respective longitudinal opening ending point are spaced apart from each other along the longitudinal axis (L) of the support structure.
In one embodiment of the invention, the covering includes or is essentially made from at least six strip-shaped elements substantially surrounding the support structure and being arranged in such a way that allows for the formation of a longitudinal opening, preferably two longitudinal openings, more preferably four longitudinal openings, most preferred six longitudinal openings. Thereby, the longitudinal opening(s) extend(s) from a respective longitudinal opening starting point to a respective longitudinal opening ending point. Thereby, the respective longitudinal opening starting point and the respective longitudinal opening ending point are spaced apart from each other along a longitudinal axis (L) of the support structure.
In one embodiment, the covering includes or is essentially made from at least six strip-shaped elements having one or more longitudinal openings such as a cut, preferably one or more longitudinal cuts, most preferred six cuts. Thereby, the longitudinal opening(s) such as a cut extend(s) from a respective longitudinal opening starting point to a respective longitudinal opening ending point. Thereby, the respective longitudinal opening starting point and the respective longitudinal opening ending point are spaced apart from each other along the longitudinal axis (L) of the support structure.
With the context of the present invention, the at least one strip-shaped element includes a region in which the two longer outer edges of the strip-shaped element are non-fixedly connected to one another either by an overlap or they adjoin tightly to one another in such a way that substantially no longitudinal opening is generated in between the two longer outer edges of the strip-shaped element and thus between the support structure and the covering.
With the context of the present invention, the at least two, four, or six strip-shaped elements include a region in which the respective longer outer edges of the strip-shaped elements are non-fixedly connected to one another either by an overlap or they adjoin tightly to one another in such a way that substantially no longitudinal opening is generated in between the respective longer outer edges of the strip-shaped element and thus between the support structure and the covering.
In view of the foregoing disclosure, according to the invention the covering may include one or to more cuts in the strip-shaped element(s) in order to form a longitudinal opening in the covering. Each cut extends from a respective first cut starting point to a respective first cut ending point. Thereby, the first cut starting point and the first cut ending point are spaced apart from each other along the longitudinal axis of the stent.
With the above context, a covering including one or more cuts reduces the sewing effort and a strip-shaped element of the invention with more than one cut increases the symmetry of the artificial cardiac valve and increases the yield of the material for the cover. This holds true, for instance, where the cover is made of pericardium, where as a natural product it is not necessarily easy to find a large homogenous area of pericardium that achieves the required specifications over the entire area.
According to the claimed invention, the longitudinal opening such as a cut extends at least partially along the intermediate area of the support structure (i.e., in the area of the covering in which it enwraps the intermediate section of the stent). Furthermore, the longitudinal opening (e.g. a cut) divides the covering into two sections. One of these sections is present on a first side of the longitudinal opening. The other section lies opposite the first section on a second side of the longitudinal opening. These two sections are relatively movable to each other and either overlap along the longitudinal opening or tightly adjoin one another without leaving a substantial gap (e.g. in case of a cut). This results in the covering being able to be present in two configurations, i.e., an open (first configuration) and a closed configuration (second configuration).
In an open configuration (first configuration), a gap is present between the first section of the covering and the second section of the covering. Thereby, the gap allows a blood flow between the interior of the support structure and the outer space or outer side of the support structure across the support structure (e.g. the open cells of a stent) and the gap in the covering. Thus, the gap forms an opening (e.g. a longitudinal opening) in the covering which enables a blood flow across the longitudinal opening of the covering.
In a closed configuration (second configuration), no gap is present between the first section and the second section of the covering. Then, substantially no blood flow between the interior of the support structure and the outer space or the outer side of the support structure across the support structure (e.g. the open cells of a stent) and the gap in the covering is possible.
Typically, the covering is in its open configuration (first configuration) if blood flows from an interior of the support structure to an outer space or an outer side thereof. Likewise, the covering is typically in its closed configuration (second configuration) if blood presses the covering from an outside or from an outer space of the support structure onto the support structure. Thus, the artificial cardiac valve of the invention acts like a check valve that enables a blood flow in one direction (namely, from an interior of the support structure to an outer space thereof=antegrade blood flow), but prevents a blood flow in the opposite direction (namely, from an outer space of the support structure to the interior thereof=retrograde blood flow).
The covering can be brought into its first (open) configuration and its second (closed) configuration by a fluid pressure acting onto the covering. While it is possible that one of the first section and the second section can be lifted with respect to the respective other section in case that blood (or another liquid) presses against the covering from the interior of the support structure, no such lifting is possible if blood (or another liquid) presses onto the covering from an outer space of the support structure. Rather, in the latter case, the first section and the second section are tightly pressed onto each other, thus closing the artificial cardiac valve. Alternatively, in case of no overlap of the first and second section both sections tightly adjoin one another in order to substantially close the gap.
With the above context, in case of no overlap of the first and second section it is advantageous that less material for the covering must be spent and this may lead to a smaller profile (including a smaller diameter when crimped) for delivery of the artificial cardiac valve of the invention.
If the artificial cardiac valve is intended to be used in assisting or replacing a tricuspid valve, it is implanted to a patient such that the first end area is located in the inferior vena cava and the second end area is located in the superior vena cava of the patient. Then, the artificial cardiac valve extends through the right atrium of the patient's heart and connects the inferior vena cava with the superior vena cava.
If blood flows from the inferior vena cava and/or the superior vena cava into the artificial cardiac valve, it lifts the first section of the covering with respect to the second section and can easily enter the right atrium. If the right ventricle of the patient's heart contracts to pump blood into the pulmonary artery, the tricuspid valve typically prevents a reflux of blood into the right atrium. If the tricuspid valve does not function correctly, blood will enter the right atrium. However, then it presses the first section of the covering onto the second section of the covering or it tightly adjoins the first section of the covering to the second section of the covering so that blood substantially cannot enter the interior of the artificial cardiac valve. Thus, the blood remains in the right atrium and does not flow back (retrograde blood flow) or only in a physiologically acceptable very small amount of blood flow back into the inferior vena cava or the superior vena cava. As a result, congestion of vital organs such as the liver is avoided, which is the root cause of many complications of tricuspid regurgitation. Thus, the artificial cardiac valve—although it is exclusively located in the right atrium and does not extend across the tricuspid valve—takes over the functionality of the tricuspid valve or at least a part of this functionality and counteracts tricuspid regurgitation.
If the artificial cardiac valve is intended to assist or replace mitral valve functionality, it is implanted into the left atrium of the patient's heart such that the first end area is placed into a first pulmonary vein and the second end area is placed into a second pulmonary vein. To give an example, the first end area can be placed into the right upper pulmonary vein, and the second end area can be placed into the left upper pulmonary vein. Likewise, it would be possible to place the first end area into the right lower pulmonary vein and the second end area into the left lower pulmonary vein. It is also possible to place the first end area into the right upper pulmonary vein and the second end area into the right lower pulmonary vein. Further, it would be possible to place the first end area into the left upper pulmonary vein and the second end area into the left lower pulmonary vein. Hereby, the skilled person readily understands that also other suitable configurations exist where to place the first end area and the second end area of one or more of the artificial cardiac valves in accordance with the present invention. For instance, in an alternative embodiment, the present invention also foresees branched stent concepts for the herein disclosed artificial cardiac valve.
If blood flows then through a pulmonary vein into the left atrium, it can simply lift the first covering section with respect to the second covering section and enter the left atrium through the formed gap between the first section and the second section of the covering. After contraction of the left ventricle, blood present in the left ventricle is typically pressed into the aorta. If the mitral valve does not function properly, the blood can re-enter the left atrium. However, it then presses the first section of the covering either against the second section of the covering and thus forming an overlap or the first and second section tightly adjoin one another, and thus closing the gap between both sections. Following this, any backflow of blood into the interior of the artificial cardiac valve through the longitudinal opening in the covering (i.e. retrograde blood flow) is either avoided or at least significantly reduced to physiologically acceptable amounts of blood backflow. Thus, a reflux of blood into the pulmonary veins is prevented. Consequently, the amount of blood that can be pumped into the aorta is significantly increased.
Thereby, it is not necessary nor intended that the artificial cardiac valve crosses the mitral valve. Rather, it is predominantly located within the left atrium and may be also located in the afferent veins.
Since the artificial cardiac valve is to be implanted either predominantly into the right atrium (and then extending into the inferior vena cava and the superior vena cava) or predominantly into the left atrium (and then extending into two pulmonary veins), it can be much more easily implanted than artificial valves known from prior art having a branched shape, e.g., bifurcated shape and extending across the tricuspid valve or the mitral valve, respectively. In one embodiment of the invention, typically no specific orientation of the presently claimed artificial cardiac valve needs to be observed when implementing the same into the patient's heart. Thus, no specific markers need to be present on the artificial cardiac valve in an embodiment.
In an alternative embodiment, however, a specific orientation of the artificial cardiac valve of the invention needs to be observed when implanting the same into the patient's heart. Thus, in such instance, suitable and specific markers need to be present on the artificial cardiac valve and/or on the delivery catheter.
The presently claimed artificial cardiac valve can also be more easily manufactured than cardiac valves known from prior art. This is due to the fact that it includes only one valve entity formed by the covering. With this context, “one valve entity” means that the covering together with the support structure forms one valve entity, but its specific arrangement of strip-shaped elements, strips, sections, longitudinal openings, and/or cuts may differ/vary, and thus may result in different/varying configurations of gaps, cuts, longitudinal openings and overlapping and/or tightly adjoining sections of the covering.
With the context of the present invention, in certain instances, the expressions “strip-shaped element(s)”, “strip(s)”, and “section(s)” may be used interchangeably for the configuration of a covering and a valve entity of the invention.
In contrast, artificial cardiac valves known from prior art often require two valve entities (e.g., one to block a blood reflux into the inferior vena cava and one to block a blood reflux into the superior vena cava). The manufacturing effort is typically doubled if two different valve entities need to be connected to a stent or any other support structure.
Following the above, in accordance with the invention the gap of the covering can be formed by attaching one or more strip-shaped elements to a support structure in such a way that respective longer edge portions of the strip-shaped elements either overlap or tightly adjoin to one another and/or the gap may be formed by one or more cuts.
Accordingly, in one embodiment, the covering includes at least one additional longitudinal opening, e.g., an additional cut. Thereby, the at least one additional longitudinal opening extends from a second longitudinal opening starting point to a second longitudinal opening ending point. Like in case of the first longitudinal opening starting point and the first longitudinal opening ending point, the second longitudinal opening starting point and the second longitudinal opening ending point are spaced apart from each other along the longitudinal axis. Furthermore, the first longitudinal opening starting point and the second longitudinal opening starting point are circumferentially spaced apart from each other. Likewise, the first longitudinal opening ending point and the second longitudinal opening ending point are circumferentially spaced apart from each other. This results in at least two longitudinal openings in the covering that are distinct from each other. By applying such longitudinal openings (e.g. two cuts), it is possible to divide the covering into different sections that are movable with respect to each other so that they can provide a gap for a blood flow or close such a gap. Thus, the sections act as valve entities of the artificial cardiac valve.
In accordance with the invention, at least one longitudinal opening (e.g. at least one cut) in the covering is sufficient for basic valve functioning.
However, it turned out that 2 to 10 longitudinal openings, in particular 4 to 6 longitudinal openings, in particular 6 longitudinal openings are particularly appropriate for dividing different sections of the covering from each other. In an embodiment, the covering includes exactly 2, 4, 6, 8, or 10 longitudinal openings (e.g. cuts).
In an alternative embodiment, 1 to 9 longitudinal openings, in particular 5 to 7 longitudinal openings are appropriate for dividing sections of the covering from each other. In a further alternative embodiment, the covering includes exactly 1, 3, 5, 7, or 9 longitudinal openings (e.g. cuts).
With the context of the invention, an even number of longitudinal openings (e.g. an even number of cuts) is preferred over an uneven or odd number of longitudinal openings (e.g. an uneven number of cuts).
In an embodiment, the strip-shaped elements and the sections of the covering lying between the strip-shaped elements are symmetrically distributed over the circumference of the support structure. Such an arrangement facilitates implantation of the artificial cardiac valve since no specific orientation of the artificial cardiac valve needs to be observed.
In an embodiment, the strip-shaped elements of the covering and the sections lying between the strip-shaped elements are asymmetrically distributed over the circumference of the support structure. Then, the artificial cardiac valve is, in an embodiment, aligned during implantation such that the desired hemodynamic properties of the artificial cardiac valve result. To give an example, the valve entity of the artificial cardiac valve (formed by two sections of the covering that are movable to each other as disclosed herein) are oriented towards a tricuspid valve or a mitral valve of the patient's heart in order to allow a particularly easy blood flow from the inferior vena cava and/or the superior vena cava or any of the pulmonary veins towards the respective ventricle of the heart.
Even in case of an asymmetric arrangement of the longitudinal openings and the strip-shaped elements of the covering, the same amount of covering material is generally present in each area of the stent. By such an arrangement, the profile of the artificial cardiac valve is not negatively influenced so that an easy implantation is still possible.
In an embodiment, so-called dummy seams (i.e., seams that are only made into the material of the covering without connecting two previously non-connected parts of the covering material together), can be provided to achieve a so-called pseudo-symmetry. Such pseudo-symmetry can counteract any potential difficulties of deployment of the artificial cardiac valve for which a lack of symmetry could be responsible, e.g., asymmetric friction.
Speaking more generally, the covering includes, in an embodiment, a plurality of additional longitudinal openings. Thereby, each additional longitudinal opening extends from an own longitudinal opening starting point to an own longitudinal opening ending point. Thus, each longitudinal opening starting point is only a starting point for an individual longitudinal opening. Likewise, each longitudinal opening ending point is only an ending point for an individual longitudinal opening. It is possible by such an arrangement that the longitudinal openings extend essentially parallel to each other.
In an embodiment, if at least two longitudinal openings are present, a strip-shaped element is formed between these two longitudinal openings. In this scenario then, this strip-shaped element acts as a first section, wherein the sections of the covering on the other sides of the longitudinal openings act as second sections.
In an embodiment, such a strip-shaped element of the covering formed between two adjacent longitudinal openings extends over the full length of the longitudinal openings without interruption. There are in particular no incisions extending in an angled manner with respect to the longitudinal openings that would divide the strip-shaped element into different parts (like a flap). Rather, the strip-shaped element remains a single part of the section of the covering. If more than one strip-shaped element is present due to presence of a plurality of longitudinal openings, all of these strip-shaped elements extend over the full length of the longitudinal openings without interruption, in an embodiment.
In an embodiment, the covering includes or essentially consists of biological tissue (e.g., pericardium), collagen-based material, cellulose-based material, a polymeric fabric (e.g., a polymeric woven fabric), a polymeric non-woven, a polymeric foil and/or a composite material.
In an embodiment, the biological tissue is prepared biological tissue treated by one or more of the following method steps in any suitable order: decellularization, cross-linking, stabilization, alpha-galactosidase epitope removal.
In an alternative embodiment, it is possible to apply a coating on any of the aforementioned materials to be used for manufacturing the covering in order to enhance the biocompatibility of the covering. Such a coating is in particular provided if the material from which the covering is made is a polymeric material. With this context, in another embodiment a pharmaceutical drug-eluting material may be used for the coating.
In an embodiment, the coating may be applied by any suitable method known to the skilled person in order to increase biocompatibility of the material and/or in order to elute medically advantageous drugs.
In an embodiment, the covering is made in form of a tube. This can be achieved, e.g., by an extrusion technique. Such a manufacturing method can be particularly well applied if the covering is made from a polymeric material. By manufacturing the covering in form of a tube, the overall seam length is reduced so that the manufacturing costs are also reduced.
In an embodiment, the covering is made from a planar material layer that is sewn together with at least one seam to obtain a covering having an overall shape of a substantially cylindric jacket. Such a manufacturing method can also well be applied to coverings made from biologic tissue.
In an alternative embodiment, in case of the use of polymeric materials for the covering, a manufacturing process of the covering starting from a planar material layer can be appropriate. In an embodiment, the at least one seam extends along the longitudinal axis of the support structure in an area of the covering that does not form a strip-shaped element between two adjacent cuts. Rather, the seam is placed such that it defines an edge of a strip-shaped element or that it extends along a partial section of such an edge of a strip-shaped element. By the avoidance of placing a seam in an area of the covering that forms a strip-shaped element, the formation of an undesired weakness of the strip-shaped element is avoided.
In an embodiment, the seam extends in an area of the covering that is fixed to the support structure so that during intended operation of the artificial cardiac valve, no relative movement of such an area with respect to the support structure occurs. Then, a potential weakness of this area does not play a significant role with respect to the overall stability of the covering or the artificial cardiac valve, respectively.
In an embodiment, the covering includes tapering end areas. Such tapering end areas facilitate a fixation of the covering to the support structure if the support structure includes bulges or constrictions. Thus, the tapering end areas enable a specific adjustment of the covering onto the support structure that is to be covered or enwrapped by the covering. The tapering end areas can adapt any desired shape that is particularly well suited for fixing the covering onto the support structure.
In an embodiment, the first longitudinal opening starting point and/or the first longitudinal opening ending point is defined by a recess. This recess can have any desired shape, e.g., a circular shape, an oval shape or an angular shape such as a triangular or a quadrangular shape. Such recess facilitates the fixation of the covering to the support structure and the movability of the covering in case of structural diameter variations of the support structure or temporal diameter changes of the support structure (e.g., during deployment, a support structure such as a stent typically deploys from a transport state in which the stent is long and thin to a deployed state in which the stent is shorter and thicker, i.e., has a bigger diameter). Likewise, the second longitudinal opening starting point and/or the second longitudinal opening ending point as well as any further longitudinal opening starting point and/or any further longitudinal opening ending point can be realized as a recess. Typically, all longitudinal opening starting points and/or all longitudinal opening ending points of a covering have the same shape.
In an embodiment, the longitudinal opening extends straightly along the longitudinal axis. Such a longitudinal opening can be particularly easy to make into the covering. In an embodiment, all longitudinal openings in the covering extend straightly along the longitudinal axis. Thus, they represent a direct, linear connection between their respective longitudinal opening starting point and their respective longitudinal opening ending point.
In an embodiment, the longitudinal opening extends curvedly along the longitudinal axis. By such an arrangement, the relative size of movable sections of the covering (acting like a valve leaflet so that they can also be referred to as valve leaflet) and the relative size of sections fixedly connected to the stent can be modified. Furthermore, a curved longitudinal opening (such as a curved cut) can facilitate, in an embodiment, the abutment of the covering in the area of a varying diameter of the support structure such as a stent, i.e. in a transitional area between a bulged area and a constricted area of the support structure. If more than one longitudinal opening is present in the covering, some or all of these longitudinal opening can curvedly extend along the longitudinal axis. Then, differently shaped movable strip-shaped elements and fixed sections of the covering result.
In an embodiment, the support structure such as a stent includes a bulge in a first transitional area between the first end area and the intermediate area and/or in a second transition area between the second end area and the intermediate area. The bulge is defined as an area of the stent having a bigger diameter than the surrounding area of the stent. Such a bulge can facilitate an arrangement or a fixation of the artificial cardiac valve in the inferior vena cava or the superior vena cava or one of the pulmonary veins. In particular, if two bulges are present (one in the first transition area and one in the second transition area), an undesired displacement of the artificial cardiac valve at its implantation site is effectively prevented.
In an embodiment, the support structure (e.g. a stent) includes a plurality of alternating bulges and constrictions. The stent then appears in a longitudinal section as having a wave-shaped outer form. Such a shape enables an increase of the number of valve sections (formed by the first and the second section of the covering) of the artificial cardiac valve and further enables to decrease the individual valve cross sections. This can increase the lifetime of the artificial cardiac valve.
Typically, the support structure has a symmetric outer shape, in particular a shape that is rotationally symmetric with respect to the longitudinal axis of the support structure. Further, different orientations of the support structure during implantation may be possible, provided that a respective orientation does not impart the functionality of the artificial cardiac valve. This is typically the case as long as also the longitudinal openings and/or strip-shaped elements are symmetrically distributed over the circumference of the support structure such as a stent.
With the above context, it shall be noted that a suitable rotational orientation of the implant shall be ensured in any case.
In an embodiment, the stent has an asymmetric outer shape, in particular a rotationally asymmetric outer shape with respect to the longitudinal axis (L) as rotational axis. This enables an adjustment of the stent to the anatomy of the implantation site. In case of such an asymmetric outer shape, marker elements such as radiopaque markers can be present on the support structure and/or on the covering in order to facilitate a correct positioning of the artificial cardiac valve during implantation. Likewise, a radiopaque suture can be used as a marker element.
In an embodiment, the support structure is a self-expanding stent having a grid-like or net-like structure. Such a grid-like or net-like structure can be realized by a plurality of open cells that may be formed by a wire scaffold that optionally includes a braided structure or via suitable laser-cutting techniques (e.g. a laser-cut from an initial tubular structure). Thereby, the individual cells can have different shapes and sizes in order to selectively increase or decrease the stability, flexibility and radial forces of the stent in certain sections. Nitinol or other shape-memory materials are particularly appropriate for manufacturing the stent. For instance, the stent may be laser-cut out of a Nitinol tube.
In an embodiment, the support structure is a mechanically expandable stent such as a balloon-stent.
In an embodiment, the support structure is a stent including both a self-expanding and a mechanically expanding part.
In an embodiment, the support structure (e.g. a stent) does not include any bifurcations. It rather has an overall elongated outer shape that is yet flexible or bendable.
To achieve a partial or full overlapping of the first section of the covering and the second section of the covering or of a strip-shaped element of the covering with respect to surrounding areas of the covering, and to achieve a particularly simple delivery of the artificial cardiac valve to an implantation site, different possibilities exist:
According to one possibility, the artificial cardiac valve can be present in a compressed delivery state (also referred to as a crimped state). In such a state, the support structure has a relatively high length, but a relatively small diameter. The covering is then arranged around the support structure without significant length excess. The artificial cardiac valve can well be delivered in this delivery state by use of a typical delivery tool such as a delivery catheter, similar to, e.g., a TAVI catheter or a catheter for peripheral stents, and thereby the delivery tool being adapted to the implantation site. Such a delivery catheter typically includes an inner shaft including a prosthesis connector, an outer shaft having a sheath such as a capsule, and optionally further including a stabilizer tubing as the outermost sheath structure. In accordance with the invention, the delivery catheter is configured such that it is suitably adapted for the respective implant and the specific site of implantation. Such a delivery catheter can further include one or more steering and positioning mechanisms.
It is then released from the delivery tool and transferred from its delivery state to its deployed state (also referred to as expanded state). Upon transition of the artificial cardiac valve from its delivery state to its deployed state, it typically experiences foreshortening, i.e., a decrease of its length connected with an increase of its diameter. The covering is fixed to the stent such that individual sections can rearrange during this transition so that the first section can afterwards overlap the second section of the covering, e.g., a first strip-shaped element of the covering can overlap a second strip-shaped element of the covering being present on the opposite side of the first strip-shaped element and thereby defining a longitudinal opening along the respective longer edges of the first and second strip-shaped elements. Alternatively, a longitudinal opening may be generated by way of a cut in the first and/or second strip-shaped element. In this alternative case, the first and second strip-shaped element not necessarily overlap.
It is also possible to use a covering having an excess length with respect to the length of the support structure. This embodiment is particularly appropriate in case of a stent as support structure having a diameter that does not change over the length of the stent. For bringing an according artificial cardiac valve into its delivery state, the excess length of the covering can be folded onto the stent so as to achieve a profile (overall diameter of the artificial cardiac valve) as small as possible.
In an embodiment, the covering can be fixed with an appropriate fixing means temporarily in this folded position. An appropriate fixing means is, e.g., an easily soluble glue. But generally, such a folding results in an overall bigger diameter than in case of other variants without length excess of the covering.
A higher diameter of the artificial cardiac valve requires also a bigger size of the delivery tool. Generally, a small diameter of the delivery tool is desired since the smaller the diameter of the delivery tool, the better tolerated is an implantation making use of the delivery tool.
In an aspect, the present invention relates to a medical method for treating tricuspid valve insufficiency or mitral valve insufficiency of a patient in need thereof. This method includes the steps explained in the following:
These steps can be carried out in any desired sequence that is suitable for full and functional deployment of the artificial cardiac heart valve at a proper site of implantation.
All embodiments of the artificial cardiac valve can be combined in any desired way and can be transferred in an analogous manner to the described medical method, and vice versa.
The artificial cardiac valve 10 has a first opening 13 on its first end and a second opening 14 on its second end. Blood can enter through these openings into an interior of the artificial cardiac 30 valve 10. However, the covering 12 prevents blood from flowing out of the interior of the artificial cardiac valve 10 at other sites than the first opening 13 and the second opening 14. This is only possible through additional openings such as a longitudinal opening in the covering that will be explained in particular with respect to
The artificial cardiac valve 10 can be present in its deployed state in two configurations. In the first configuration, the so-called open configuration, a first section 120 of the covering 12 is lifted away from the stent 11 as support structure and from another section of the covering 12 that is not visible in the depiction of
When the first section 120 of the covering 12 is lifted away from the stent 11, a gap 1200 is formed between the first section 120 of the covering 12 and the stent 11 as well as between other sections of the covering 12. Thereby, it is possible for blood that has entered the interior 15 of the artificial cardiac valve 10 through the first opening 13 or through the second opening 14 to exit this interior 15 through the gap 1200.
The covering 22 further includes a first connection section 228 and a second connection section 229. In both connection sections 228, 229, a seam is to be provided (indicated by “xxxx”) so that the covering 22 can be rolled like a cylinder jacket and sewn together with two seams, one in the first connection section 228 and one of the second connection section 229. The section between the first connection section 228 and the second connection section 229 will not be sewn. Rather, this section of the covering 22 will be left open and constitutes a cut-like element, even though it is not necessary to provide a cut at this site. Thus, the second section 227 is then directly adjacent to the first section 224, but still be movable with respect to the first section 224. Such an arrangement minimizes the sewing effort, reduces the manufacturing costs and the possibilities of manufacturing errors. This leads to an increase in product safety.
To better visualize a concordance between the cross-sectional view of
If the artificial cardiac valve 30 of
The artificial cardiac valve 30 is depicted in
Blood can flow through this gap 3200 from an interior 35 of the artificial cardiac valve 30 to an outside thereof.
A covering 42 is connected to a stent 41 as support structure by a plurality of seams 420 in different areas of the stent 41 or the covering 42, respectively. The seams should ensure an optimal attachment of the covering to the stent. Further or additionally, seams are also possible to add at certain points, with which the covering is slidably attached to the stent, so that the covering can occupy an energetically favorable position with little tension in the material when crimping and expanding during delivery. Thus, there are not only seams in the area of a first opening 43 and a second opening 44, but also in intermediate areas. This increases, however, the efforts to be made for sewing the covering 42 to the stent 41.
The cut pattern of the covering 42 is also more complex in this embodiment. This cut pattern is depicted in
In an embodiment of the invention, the covering includes a three-dimensional outer shape.
In an embodiment of the invention, the covering includes a three-dimensional outer shape that protrudes from the surface of the coverage towards the surrounding anatomical site.
In this exemplary embodiment, each of these sections 424, 425, 426, 427 (strip-shaped elements) includes a first tapering end area and a second tapering end area. The individual first tapering end areas are collectively marked with the numeral reference 428, whereas the individual second tapering end areas are collectively marked with the numeral reference 429.
Each of the sections 424, 425, 426, 427 (strip-shaped elements) includes a first edge and a second edge. Thus, the covering 42 has eight section edges in total, namely a first section edge 42-1, a second section edge 42-2, a third section edge 42-3, a fourth section edge 42-4, a fifth section edge 42-5, a sixth section edge 42-6, a seventh section edge 42-7, and an eighth section edge 42-8. Thereby, always a second edge of one section lies directly opposite a first edge of an adjacent section across the respective cut being present between the sections. It should be noted that an end area of the fourth section 427 will be sewn to an end area of the first section 424 in order to give the covering 42 the shape of a cylinder jacket. The central area between the fourth section 427 and the first section 424 will not be sewn together so that a cut remains between these two sections. Thus, the first section 424 is movable with respect to the fourth section 427. Thereby, it is not necessary to make a distinct cut between these sections, because it will be automatically present if the sections are not sewn together over the entire width of the covering 42.
A schematic cross-sectional view through an according configuration of a covering suited to be used for an artificial cardiac valve is shown in
The individual sections or strip-shaped elements of coverings 72 and 82 of
A difference between the cut pattern of the covering 92 of
Due to the four individual cuts 920, five sections or respective strip-shaped elements, namely a first section 921A, a second section 922, a third section 923, a fourth section 924 and a fifth section 921B are formed. When the planar layer of the covering 92 is rolled to form a cylinder jacket and sewn along its lower edge 925 and its upper edge 926, the first section 921A and the fifth section 921B are combined to form a common section. Thus, all in all four sections result also in this embodiment.
One section, namely the common section of first section 921A and the fifth section 921B includes a seam along its longitudinal axis. Since such a seam represents a structural weakness of the respective section, it is particularly appropriate if the common section of the first section 921A and the fifth section 921B is not a movable section acting as valve leaflet, but is rather a section that is sewn to a stent of the respective cardiac valve. An according schematic cross-sectional view through a valve configuration making use of the covering 92 is depicted in
It should be noted that the embodiment depicted in
The stent 1011 shown in
In view of all the foregoing disclosure, further embodiments of the present invention are reflected by the following consecutively numbered embodiments:
| Number | Date | Country | Kind |
|---|---|---|---|
| 19199843.4 | Sep 2019 | EP | regional |
This application is a 35 U.S.C. 371 US National Phase and claims priority under 35 U.S.C. § 119, 35 U.S.C. 365(b) and all applicable statutes and treaties from prior PCT Application PCT/EP2020/076483, which was filed Sep. 23, 2020, which application claimed priority from European Application Serial Number 19199843.4, which was filed Sep. 26, 2019.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/076483 | 9/23/2020 | WO |
