Patent Description:
Implantable tube valves for implanting in human vessels like the urinary tract, vas deferens, or fallopian tube, such as disclosed in <CIT> provide a reliable and efficient solution that can be switched on and off at will. Typically, the inner diameter of such vessels is smaller than three millimeter. For these sizes, the publication discloses an implantable tube with a valve member that is pivotable within the tube, between an open position and closed position. The open position is designed to minimally restrict the passage of human fluids, cells or particles, e.g. blood, lymphatic fluid, egg or sperm cells, urine, or other secretion. Conversely, the closed position is designed to block the passage of such fluids, cells or particles. Purposes can be found in e.g. birth control, incontinence treatment, blood/kidney dialysis, or controlled draining of excess fluid from the body.

The valve member of the implantable tube described in <CIT> is driven by an actuator mechanism comprising a pivot member. The pivot member converts a force from the actuator into a rotation of the valve member, that may open or close the implantable tube device. Due to the small size of the device, manufacturability and quality of the final product are essential aspects that need to be considered during the design. A problem with this type of pivot member, however, is that it increases the
lateral extension of the tube when mounted in the tube wall, which limits the available space for passage through the implantable tube valve, thereby potentially reducing the effectivity of the device.

For these dimensions it is difficult to propose a solution for a pivot member that is easy to manufacture and assemble, and that can be mounted into the wall of an implantable tube valve without significantly increasing the thickness of the tube wall.

In one aspect, it is aimed to provide an implantable tube valve with a pivotable tube valve member that is biased towards an open or closed position by a biasing arrangement that is easy to manufacture and assemble. An implantable tube valve is provided that can be implanted in a human vessel, and that comprises a tube with an inner and outer tube wall extending between two axial tube ends and a valve member mounted inside the inner tube wall.

The valve member is pivotable between an open position and a closed position. The valve member is connected to a pivot shaft supported by the tube. The pivot shaft is connected to a pivot member driven by an actuation mechanism. The implantable tube valve further comprises at least one biasing element connected to the pivot member and arranged for bistably biasing the valve member towards the open or closed position.

The pivot member is substantially curved, having a curvature following a contour of the inner tube wall to limit a lateral extension of the implantable tube valve.

In some embodiments, the tube comprises a cavity between the inner and outer tube wall, for enclosing at least the pivot member. This may limit the lateral extension of the implantable tube valve even further.

Additionally or alternatively, the biasing element at least comprises two bow-shaped rods that are interconnected at both ends in a mirrored fashion. In an example embodiment, each bow-shaped rod has a middle section with an increased bending stiffness with respect to a distal and proximal end section bending stiffness.

Optionally, the implantable tube valve may comprise an actuator mechanism with a heating circuit arranged for heating shape memory alloy tension wires by means of an electrical current, causing an actuation force on the pivot member by reversible contraction of the tension wires. In an example embodiment, a tension wire is mechanically connected to at least two respective terminals of the heating circuit at one end, to provide a current running therethrough, and mechanically connected to the pivot member at another end, so that the current runs through the tension wire without branching off to the pivot member. This allows the electrical current for heating the at least one tension wire to be contained within the tension wires instead of flowing through other components which could cause undesired welding effects.

Preferred embodiments are described in the dependent claims.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs as read in the context of the description and drawings. In some instances, detailed descriptions of well-known devices and methods may be omitted so as not to obscure the description of the present systems and methods. It will be further understood that the terms "comprises" and/or "comprising" specify the presence of stated features but do not preclude the presence or addition of one or more other features.

The term "mount" is used in its ordinary meaning to emphasize that many mounting arrangements are possible. These arrangements include physical shaft mounts, ball bearing mounts or any other mechanical arrangement providing a rotational degree of freedom for the valve member mounted in the mount. The rotational degree of freedom defines an axis of rotation or pivot axis that is transverse to the implantable tube. Preferably, the mount is formed partly by the tube, and a corresponding mount part formed by the valve member.

By the term 'extending continuously' e.g. between axial tube ends, it is indicated that there are no substantial deviations present between said extensions, notably no or very limited protruding outer features, in respect of the implantable tube. In particular, the implantable tube extending continuously between the axial tube ends indicates that there is no or very limited spatial deviation from the tube form along the entire tube. The term continuous does nevertheless not preclude the presence of minor protrusions or depressions, e.g. for forming an actuator housing, sealing edge, mounting or valve seat on a smaller scale or for forming a rugged surface e.g. for fixed insertion in the human vessel, e.g. in the form known for stents. It is indicated on a larger scale that the general flow through the object may be unobstructed due to the tube's continuous form, or that the object itself does not substantially deviate from a tube form. In particular, depending on its application, the actuator actuating the valve member is shaped in elongated form along the tube in a way that can be absorbed by stretching the surrounding tissue.

A 'heating circuit' may comprise one or more analog or digital hardwire elements configured to perform operational acts in accordance with the present systems and methods, such as to provide control signals to the various other module components. The processor may be a dedicated processor for performing in accordance with the present system or may be a general-purpose processor wherein only one of many functions operates for performing in accordance with the present system. The processor may operate utilizing a program portion, multiple program segments, or may be a hardware device utilizing a dedicated or multi-purpose integrated circuit. Any type of processor may be used such as dedicated or shared one. The processor may include micro-controllers, central processing units (CPUs), digital signal processors (DSPs), ASICs, or any other processor(s) or controller(s) such as digital optical devices, or analog electrical circuits that perform the same functions, and employ electronic techniques and architecture. The controller or processor may further comprise a memory that maybe part of or operationally coupled to the controller. The memory may be any suitable type of memory where data is stored. Any medium known or developed that can store and/or transmit information suitable for use with the present systems and methods may be used as a memory. The memory may also store user preferences and/or application data accessible by the controller for configuring it to perform operational acts in accordance with the present systems and methods.

While example embodiments are shown for systems and methods, also alternative ways may be envisaged by those skilled in the art having the benefit of the present disclosure for achieving a similar function and result. some components may be combined or split up into one or more alternative components. Finally, these embodiments are intended to be merely illustrative of the present system and should not be construed as limiting the appended claims to any particular embodiment or group of embodiments. Thus, while the present system has been described in particular detail with reference to specific exemplary embodiments thereof, it should also be appreciated that numerous modifications and alternative embodiments may be devised by those having ordinary skill in the art without departing from the scope of the present systems as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative manner and are not intended to limit the scope of the appended claims.

Any reference signs in the claims do not limit their scope; several "means" may be represented by the same or different item(s) or implemented structure or function; any of the disclosed devices or portions thereof may be combined together or separated into further portions unless specifically stated otherwise. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage.

Turning now to <FIG>, there is illustrated an embodiment of an implantable tube valve <NUM>, comprising an implantable tube <NUM> having an inner and outer tube wall extending between two axial tube ends. The implantable tube valve <NUM> further comprises a valve member <NUM> mounted on a pivot shaft <NUM> which is supported by the tube <NUM>, with the valve member pivotable between an open and closed position, allowing or closing off passage through the tube <NUM>, respectively. A pivot member <NUM> is arranged for driving the pivot shaft <NUM> from the outer tube wall by an actuation force from an actuator mechanism <NUM>. The implantable tube valve <NUM> comprises a biasing element <NUM> connected to the pivot member <NUM> and arranged for preloading the pivot member <NUM> to bistably bias the valve member <NUM> towards the open or closed position. The pivot shaft <NUM> rotates the valve member <NUM> between an open position and a closed position. The pivot member <NUM> is substantially curved, having a curvature following a contour of the inner tube wall to limit a lateral extension of the implantable tube valve <NUM>. The pivot member <NUM> can for example be manufactured out of a base material tube, e.g. by laser cutting or water-jet cutting. Preferably, the radius of curvature of the base material tube is chosen to match the radius of curvature of the implantable tube <NUM> as close as possible, with a small radial clearance gap to allow rotation of the pivot member <NUM>, as explained later on in this application with reference to <FIG>. Accordingly, this may result in a pivot member that is easy to manufacture and assemble, and that can be mounted into the wall of an implantable tube valve with a minimal increase of the thickness of the tube wall.

<FIG> shows a preferred embodiment of a pivot member <NUM>, which substantially reduces the wall thickness of the tube <NUM> required to enclose the pivot member <NUM>, compared to other types of pivot members. The pivot member <NUM> has a curved inner and outer surface, of which the center of curvature is located on the pivot axis <NUM> of the pivot shaft <NUM>. In the specific embodiment shown in <FIG>, the inner and outer surface of the pivot member <NUM> are cylindrically curved with a center of curvature coinciding with the center of curvature of the inner tube wall. Alternatively, the inner and outer surface of the pivot member <NUM> may have a non-constant radius of curvature or may comprise straight segments.

The pivot member <NUM> is shown essentially having three mounts radially extending from the pivot shaft <NUM>. Two opposing mounts 410a and 410b are arranged for transferring the actuation force from the actuator mechanism to the pivot shaft. For this purpose, mounts 410a and 410b may comprise cylindrically rounded cutouts for mounting the actuator connectors <NUM>. One mount 410c is arranged for transferring the preload force from the biasing element (not shown) to the pivot shaft. Mount 410c may be extending perpendicularly to the opposing mounts 410a and 410b and may comprise a rounded cutout for mounting the biasing element <NUM>. Alternatively, the pivot member <NUM> may comprise any other number of mounts for transferring actuation or preload forces, placed at any other orientation with respect to the pivot shaft <NUM> and to each other, as deemed suitable for actuation and biasing of the valve member <NUM>.

The pivot member <NUM> and its mounts 410a, 410b and 410c may be an integrally formed part comprising cutouts, holes or pockets to remove excess material, e.g. for reducing the weight or for increasing structural flexibility if preferred or required. Alternatively, the pivot member <NUM> may be assembled from multiple parts and may comprise areas with different material properties or thickness.

The embodiment of the pivot member <NUM> of <FIG> preferably has a radius of curvature that is bigger than the outer radius of curvature of the tube <NUM>. The difference between these radii provides a radial gap between the tube <NUM> and the pivot member <NUM> that allows a rotation of the pivot member <NUM> around the pivot axis <NUM> over a pivot angle, of which a minimum value is required to fully open and close the valve member <NUM>.

However, any radial gap also undesirably increases the lateral extension of the implantable tube valve <NUM>. Therefore, the radial gap is preferably optimized to a minimum radial gap such that the allowed rotation over pivot angle α is just sufficient to functionally operate the valve member <NUM>, while the lateral extension of the implantable tube valve <NUM> is minimized. This can be done by means of Equation <NUM>, <MAT> wherein alpha equals the pivot angle of the pivot member <NUM> in radians, RP and RB equal, respectively, the radius of curvature of the pivot member <NUM> and the tube <NUM>, b equals the width of the pivot member <NUM> at the end of the opposing mounts 410a and 410b, and a equals the length of the curved segment of one of the opposing mounts 410a or 410b with height h<NUM> and radius of curvature RP, and can be calculated by Equation <NUM>.

Preferably, the distance between the cylindrically rounded cutouts for mounting the actuator connectors on the two opposing mounts 410a and 410b is large, i.e. about <NUM>-<NUM>% of the tube diameter (<NUM>RB), so as to increase the transmission ratio between the actuation force provided by tension wires M1, M2 and the resulting actuation torque on the pivot shaft <NUM>. The same holds for other types of connections between tension wires M1, M2 and pivot member <NUM>. However, for given radii of curvature of the pivot member <NUM> and the tube <NUM>, an increasing distance (i.e. increased h<NUM>) leads to a decreasing pivot angle. Similarly, an increasing width of the pivot member <NUM> at the end of the opposing mounts 410a and 410b leads to a decreasing pivot angle.

Therefore, using Equations <NUM> and <NUM> the geometrical properties of a curved pivot member <NUM> can be chosen such that, for a given tube <NUM> diameter and a given pivot angle, the pivot member can be placed as close as possible to the inner tube wall such that the lateral extension of the implantable tube valve <NUM> is minimalized.

<FIG> provides an axial plane cross section view of an implantable tube valve <NUM>, comprising an embodiment of a pivot member <NUM> with a curved inner and outer surface concentrically aligned with the tube <NUM> to limit the lateral extension of the implantable tube valve <NUM>. The pivot member <NUM> is mounted on a pivot shaft <NUM>, supported by the tube <NUM> and able to pivot the valve member <NUM> between an open position (as shown in <FIG>) and a closed position. The inner tube wall of tube <NUM> may be eccentrically aligned with the outer tube wall of tube <NUM>, such that the wall thickness of tube <NUM> is largest on one side of the tube <NUM>. Alternatively, the inner tube wall may be concentrically aligned with the outer tube wall, such that the tube <NUM> has an equal wall thickness around the circumference.

One side of the tube <NUM>, e.g. the side with the largest wall thickness, may comprise at least one cavity <NUM> such that elements of the implantable tube valve, e.g. the pivot member <NUM>, actuator (not shown) and biasing element (not shown), can be enclosed within the tube wall. Preferably, the cavity is covered by a cover <NUM> such that a smooth outer contour of the tube <NUM> is created. The tube <NUM> may comprise more than one cavity or channel covered by more than one cover, e.g. if preferred from a functional point of view to accommodate elements of the implantable tube valve on different sides of the tube <NUM>, or if preferred from a manufacturing or assembly point of view. Multiple cavities or channels may be interconnected. Alternatively, the tube <NUM> may be assembled from multiple parts such that an at least partially hollow tube wall is created for accommodating elements of the implantable tube valve.

In other or further embodiments, the inner tube wall of tube <NUM> is eccentrically aligned with the outer tube wall of tube <NUM>, whereas the cover <NUM> is an integrally formed part of the tube <NUM> forming an enclosure for mounting elements of the implantable tube valve <NUM>, e.g. pivot member <NUM>, actuator, biasing element, within the tube wall on the side of the tube with the substantially larger wall thickness.

Preferably, the volume of the cavity <NUM> is substantially curved, to house the curved pivot member <NUM>.

For example, to take up minimal space for the actuator, cavity <NUM> can be formed by having an outer, e.g. spherical shape, and inner tube, containing the valve <NUM>. If the midpoint of the spherical shape lies eccentric to the midpoint of the inner tube, a greater surface appears on the other eccentric side. If this surface is hollowed out, a curved or angled cavity <NUM> may be created. In this cavity <NUM> a pivot member <NUM> can be mounted with a shape that resembles the contour of the interior space. Such a pivot member <NUM> may not be able to rotate full circle, since it would be blocked by the inner tube wall. However, a sufficient rotation angle may be allowed within the cavity <NUM>, enough to pivot the valve member <NUM> through the pivot shaft <NUM> between the open and closed position.

<FIG> shows a further embodiment of implantable tube valve comprising a curved pivot member <NUM> and a biasing element <NUM>. In the illustrated embodiment, the pivot member <NUM> is connected to the valve member <NUM>, extending eccentrically from a pivot axis <NUM> defined by pivot shaft mount <NUM>, and is driven by an actuator (not shown).

The biasing element <NUM> is mounted to the tube <NUM> and the pivot member <NUM> and arranged to exert a biasing force Fp between them, arranged for resulting in a preloading torque on the valve member <NUM>. The pivot member <NUM> and the tube <NUM> comprise cylindrically rounded cutouts that match cylindrically rounded ends 820a and 820b on the biasing element <NUM>, such that the biasing element <NUM> is mounted to the tube <NUM> in a way that allows rotation along the contour of the cylindrically rounded end 820a and to the pivot member <NUM> in a way that allows rotation along the contour of the cylindrically rounded end 820b.

Alternatively, the biasing element <NUM> may be connected to the tube <NUM> and/or the pivot member <NUM> in other ways to exert a biasing force between the two, e.g. by bearings such as knife-edge bearings. Alternatively, the biasing element <NUM> may be an integral part of the tube <NUM> and/or the pivot member <NUM>.

The pivot member <NUM> preferably is a substantially curved element comprising a central hole for mounting to the pivot shaft <NUM> and a cylindrically rounded cutout on an edge of the pivot member for mounting the cylindrically rounded end 820b of the biasing element <NUM> at a radial distance from the pivot shaft <NUM>. However, the pivot member <NUM> may be any differently shaped body suitable for the transmission of the biasing force into a preloading torque on the valve member <NUM>, e.g. a body containing a crank or lever.

The biasing element <NUM> is mounted to the tube <NUM> such that, in uncompressed state of the biasing element <NUM>, the valve member <NUM> is bistably biased to either an open or closed position.

Upon rotation of the pivot member <NUM> by an actuator, such that e.g. the valve member <NUM> is pivoted away from an open position or closed position, the biasing element <NUM> is compressed until it reaches a neutral state, in which the centerline <NUM> of the biasing element <NUM> intersects the pivot axis <NUM> of the pivot shaft <NUM>. In this neutral state, the biasing element is maximally compressed, thus exerting a maximum force between the tube <NUM> and the pivot member <NUM> but without a resulting torque on the pivot member <NUM>. If the pivot member is rotated away from the neutral state, the built up force in the biasing element <NUM> is released into a torque on the pivot member <NUM>, thereby biasing the valve member <NUM> to a closed or open position. As such, the biasing element <NUM> opposes the rotation of the pivot member <NUM> when rotating towards the neutral state, and assists the rotation of the pivot member <NUM> when rotating away from the neutral state.

In some embodiments, the pivot member is designed as a separate part on the outside of the tube <NUM>, leading to only a very minute extension of the implantable tube valve <NUM> in lateral direction. This extension may be between <NUM> and <NUM> micron. The pivot member <NUM> is preferably designed having an inwardly curved inner and outer surface to further limit the lateral extension of the implantable tube valve <NUM>.

The depicted connection by means of cylindrically rounded ends 820a and 820b allows for a flush connection between the biasing element <NUM> and pivot member <NUM>. This limits the lateral extension of the implantable tube valve <NUM>. Alternative connections such as a knife-edge bearing or elastic bearing between the biasing element <NUM> and the pivot member <NUM> may provide the same benefit.

In other or further embodiments, the biasing element <NUM> is formed by two bow-shaped rods that are interconnected at both ends in a mirrored fashion. This arrangement allows for a very compact arrangement that can be manufactured in very minute dimensions e.g. manufactured out of thin plate material, potentially as a single piece, and can easily be assembled into an implantable tube valve, necessary for applications in human vessels.

<FIG> shows a biasing element <NUM> according to a further embodiment. The biasing element <NUM> comprises two bow-shaped rods 810a and 810b that are interconnected at their ends in a mirrored fashion. The biasing element <NUM> comprises cylindrically rounded ends 820a and 820b. The bow-shaped rods 810a and 810b may form a compression spring that shortens, e.g. along centerline <NUM> upon exertion of an external force Fp between ends 820a and 820b. Due to the bow shape of the rods 810a and 810b, the compression stiffness CD of the biasing element <NUM> is defined by the bending stiffness of the rods 810a and 810b. The biasing element <NUM> preferably is an integrally formed planar structure with uniform thickness, e.g. formed out of a plate or a tube.

Alternatively, the biasing element <NUM> may be composed of several parts that are assembled, e.g. the bow-shaped rods 810a and 820b may be manufactured individually and later assembled to form the biasing element <NUM>. The individual parts may be formed out of different materials with different structural properties. The biasing element <NUM> may also comprise a non-uniform thickness to alter its functional behavior, e.g. parts of the biasing element <NUM> may have e.g. larger thickness, flanges or raised edges to increase the stiffness of those parts.

Similarly, parts of the biasing element <NUM> may comprise e.g. smaller thickness, holes, pockets or cutouts to reduce the stiffness of those parts. Although the biasing member is quite scalable in dimensions, for human vessels it can be manufactured in very minute dimension, e.g. with a length dimension of about <NUM>-<NUM> and with a thickness of about <NUM>-<NUM> micrometer.

<FIG> shows in detail the embodiment of the biasing element <NUM> of <FIG>. The biasing element <NUM> preferably is a planar structure comprised of interconnected bow-shaped rods <NUM> and two cylindrically rounded ends 820a and 820b. Upon an external compressive force Fp exerted on the ends <NUM>, the biasing element <NUM> shortens along the centerline <NUM> and widens in a lateral in-plane direction, caused by a bending deformation of the bow-shaped rods <NUM>. To avoid bending or buckling of the biasing element <NUM> in an out-of-plane direction, the biasing element <NUM> may be built into an enclosure that restricts any out-of-plane movement of the biasing element <NUM> or parts thereof. Alternatively, the biasing element <NUM> may have an out-of-plane bending or buckling stiffness larger than an in-plane bending stiffness.

Each bow-shaped rod preferably comprises a middle section <NUM> and two end sections 840a and 840b. The middle section <NUM> may have a larger cross section area than the end sections <NUM>, thus providing a bending stiffness at the middle section <NUM> higher than at the end sections <NUM>. In some embodiments, the bow-shaped rods <NUM> are interconnected at their end sections 840a and 840b in a mirrored fashion, wherein the mirroring plane is defined by the centerline <NUM> of the biasing element <NUM> and a normal to a frontal plane of the biasing element <NUM>.

In a preferred embodiment, the biasing element <NUM> has a symmetrical shape, both horizontally and vertically. As such, the biasing element <NUM> may be described having four quadrants, which are symmetrically mirrored along a horizontal and vertical centerline with respect to each other. Accordingly, each quadrant may for example comprise half of a rounded end 820a, 820b. From there, end section 840a, 840b of bow-shaped rod <NUM> may initially curve inward, towards horizontal centerline <NUM>. Next, end section 840a, 840b may curve outward, away from horizontal centerline <NUM>. Preferably, end section 840a, 840b transitions into middle section <NUM>, which may run parallel to horizontal centerline <NUM>, while the cross section area of the bow-shaped rod gradually increases. In some embodiments, the cross section area may reach a maximum at a vertical centerline (not shown) of the biasing element, e.g. running through the center of middle sections <NUM> of the two bow-shaped rods <NUM>.

In <FIG>, there is illustrated another embodiment of an implantable tube valve <NUM>. <FIG> provides a section view of the implantable tube valve <NUM>, showing a valve member <NUM> mounted on a pivot shaft <NUM> which is supported by a tube <NUM>. The pivot shaft <NUM> rotates the valve member <NUM> between an open position and a closed position, allowing or closing off passage through the tube <NUM>, respectively. The embodiment of <FIG> further shows the tube <NUM> comprising a tube contour <NUM>, enclosing a heating circuit <NUM> part of an actuator <NUM>.

<FIG> provides a detailed view of the implantable tube valve <NUM>, showing an actuator <NUM> and a biasing arrangement <NUM> integrated in the wall of the tube <NUM>. The actuator <NUM> comprises a heating circuit <NUM> and tension wires M<NUM> and M<NUM>. The tension wires M<NUM> and M<NUM>, when heated over a certain length may result in substantial contraction of the tension wires, resulting in actuation forces on the pivot member <NUM>. The actuation forces are converted by the pivot member <NUM> into an actuation torque on the pivot shaft <NUM> for opening or closing the valve member <NUM>. This tension wire arrangement is especially advantageous in the context of the present disclosure, but can also be used to good purpose in other actuators, notably of a type having an elongated geometry such as tubes, cylinders or bars.

Pivot member <NUM> is connected to valve member <NUM>, extending eccentrically from a rotation axis defined by pivot shaft <NUM>, and is driven by the actuator <NUM>. The actuator <NUM> comprises a heating circuit <NUM> and first and second tension wires M<NUM>, M<NUM> formed of a shape metal alloy, connected to the heating circuit <NUM> and connected by means of actuator connectors <NUM> on opposite sides of the pivot member <NUM> along the tube wall, thereby connecting the pivot member <NUM> to a position fixed relative to the tube <NUM>, so that, in use, the valve member <NUM> is pivoted in open position by heating the first tension wire M<NUM> and the valve member <NUM> is pivoted in closed position by heating the second tension wire M<NUM>. A number of variations are possible, e.g. by inverting the wire geometry and using push instead of pulling arrangements of the tension wires. Preferably, the tension wires M<NUM>, M<NUM> are of a form that contracts when heated. Shape metal alloy suitable for such may for instance be a NiSn alloy known as Nitinol, but other shape metal alloys can be used to purpose.

Tension wires M1, M2 may comprise a single-strand or multi-strand wire and may comprise multiple interconnected parts. Besides a circular cross-section, tension wires M1, M2 may have differently shaped cross-sections, e.g. rectangular, in dependence of the manufacturing process. Tension wires M1, M2 may also be hollow or comprise pockets or cut outs. Alternatively, parts of tension wires M1, M2 may be reinforced, e.g. by having an increased cross sectional area or different material properties. Tension wires M1, M2 may each be differently shaped than the other and may each comprise a different response to heating by the heating circuit <NUM>. As an alternative embodiment, tension wires M1, M2 may each comprise multiple wires M1a, M1b and M2a, M2b respectively, e.g. to intrinsically provide a current loop to and from the heating circuit <NUM> as shown in <FIG>.

The actuator connectors <NUM> comprise a cylindrically rounded outer surface that matches a cylindrically rounded cutout in pivot member <NUM>, to form a rotatable connection between the actuator connector <NUM> and pivot member <NUM>. The connection between actuator connector <NUM> and pivot member <NUM> may be flush to limit the extension of the tube contour <NUM> in lateral direction. Alternatively, an actuator connector <NUM> may be an integral part of pivot member <NUM> or of tension wire M1 and/or M2, e.g. by means of elastic hinges. Alternatively, instead of by means of actuator connectors <NUM>, tension wires M<NUM>, M<NUM> can be directly coupled to pivot member <NUM>, e.g. by soldering, welding, gluing or threading.

Turning back to <FIG>, pivot member <NUM> preferably is a substantially curved element comprising a central hole for mounting to the pivot shaft <NUM> and two cylindrically rounded cutouts on an edge of the pivot member for mounting the actuator connectors <NUM> at a radial distance from the pivot shaft <NUM>, however the pivot member <NUM> may be a differently shaped body suitable for a transmission of actuation forces into an actuation torque on the pivot shaft <NUM>, e.g. a body containing one or more cranks or levers.

Pivot member <NUM> is preferentially designed as a separate part on the outside of the tube <NUM>, leading to only a very minute extension of the tube contour <NUM> in lateral direction. The pivot member <NUM> may be designed having a curved inner and outer surface concentrically aligned with the tube <NUM> to further limit the extension of the tube contour <NUM>.

Heating circuit <NUM> is preferably geared to a wireless charging device (not shown) but may also be powered by other means, e.g. a battery pack etc. In the shown embodiment the heating circuit comprises a charging capacitor (not shown) electrically connected to a charging antenna <NUM> arranged along the implantable tube valve <NUM>. The heating circuit <NUM> comprises corresponding logic to heat a first or second tension wire M<NUM>, M<NUM> when the charging capacitor is charged with a threshold charge, charged by the charging antenna <NUM>.

The logic may have further gearing options, e.g. a (wireless) readout, such as status check options or reset options, and is preferably operated by a coded signal that only activates the heating circuit <NUM> when a corresponding security code is transmitted. In its simplest form, the wireless charging system functions as a bistate switch, switching the valve member <NUM> from open to closed position or from closed to open, depending on the initial arrangement.

The outer surface of the tube <NUM> may be covered by a foundation <NUM>, comprising a material that facilitates adhesion to the lumen of the human vessel the implantable tube valve <NUM> is implanted in, such as a biocompatible meshed, porous or fabric material. Alternatively, the foundation <NUM> or tube <NUM> may comprise radially extending protrusions, e.g. spikes or hooks that form a mechanical bonding with the surrounding tissue, thereby fixating the implantable tube valve <NUM> to the vessel lumen.

<FIG> shows an embodiment of an actuator mechanism <NUM> of an implantable tube valve <NUM>. The actuator mechanism comprises a heating circuit <NUM> arranged for heating tension wires M1, M2 by means of an electrical current through the tension wires. The tension wires M1, M2 reversibly contract when heated by the heating circuit and expand when cooled, thereby providing an actuation force to the pivot member <NUM>. Alternatively, the tension wires M1, M2 may reversibly expand when heated by the heating circuit and contract when cooled. Preferably, the tension wires M<NUM>, M<NUM> are of a form that contracts when heated. Shape metal alloy suitable for such may for instance be a NiSn alloy known as Nitinol, but other shape metal alloys can be used to purpose.

The actuation force may be provided by the tension wires M1, M2 being directly coupled to the pivot member <NUM>, e.g. by being soldered, welded, glued or threaded to each other. Preferably, at least one of the tension wires M1, M2 is coupled to a connector, with said connector being mounted in the pivot member <NUM>. For example, each of tension wires M1, M2 may be mounted to the pivot member by means of actuator connector <NUM>. The actuator connector <NUM> may comprise a cylindrically rounded end engageable with a cylindrically rounded cutout on the pivot member to form a rotatable connection. A benefit of having a cylindrically rounded contact surface between the actuator connector <NUM> and the pivot member <NUM> may be that the actuation force on the actuator connector <NUM> is exclusively converted into a torque on the pivot member <NUM>, which may facilitate maintaining proper alignment between the pivot member and the actuator connector. Conversely, in e.g. a conical contact surface, the actuation force is converted into a torque as well as an axial force, possibly destabilizing or locking the connection between the pivot member <NUM> and the actuator connector <NUM>. The actuator connector <NUM> may be an integrally formed part of the tension wires M1, M2. Alternatively, the actuator connector <NUM> may be a separate part which is assembled to each of tension wires M1, M2 e.g. by soldering, welding, gluing or threading.

Tension wires M1, M2 may be mechanically connected to at least two respective terminals (+) (-) of the heating circuit at one end, to provide a current running therethrough, and mechanically connected to the pivot member <NUM> at another end, so that the current runs through the tension wire M1a,b, and M2a,b respectively, without branching off to the pivot member <NUM>. Each of the tension wires M1, M2 may be electrically connected to a positive and a negative terminal on the heating circuit <NUM>, such that a closed current loop is formed without current passing from the connector <NUM> to pivot member <NUM>. This has as benefit, that no currents pass from connector <NUM> to pivot member <NUM>, ensuring that connectors <NUM> can be freely mounted without running into fixation by microwelds that would arise from such currents.

Claim 1:
Implantable tube valve (<NUM>) for implanting in a human vessel, comprising:
- a tube (<NUM>), having an inner and outer tube wall extending between two axial tube ends;
- a valve member (<NUM>), connected to a pivot shaft (<NUM>) supported by the tube (<NUM>), with the valve member (<NUM>) pivotable between an open position and a closed position;
- an actuator mechanism (<NUM>), mounted on the outer tube wall;
- a pivot member (<NUM>), arranged for driving the pivot shaft (<NUM>) from the outer tube wall by an actuation force from the actuator mechanism (<NUM>); and
- at least one biasing element (<NUM>), connected to the pivot member (<NUM>) and arranged for preloading the pivot member (<NUM>) to bistably bias the valve member (<NUM>) towards the open or closed position;
wherein the pivot member (<NUM>) is substantially curved, having a curvature following a contour (<NUM>) of the inner tube wall to limit a lateral extension of the implantable tube valve.