Soft tissue anchor system for heart repair

Abstract

A soft tissue anchor system for implantation in soft body tissue, such as the mitral valve, to hold an artificial line, such as artificial chordae lines. The soft tissue anchor system 200 comprises a

Description

The present invention relates to a soft tissue anchor system for implantation in soft body tissue to hold a line. The chordae tendineae are cord-like tendons that connect the papillary muscles to the tricuspid valve and the mitral valve in the heart. The valves consist of leaflets that open and close with the beating of the heart in order to control blood flow and blood pressure within the heart. Mitral valve disease presents an important challenge to cardiac surgeons and cardiologists. Mitral regurgitation has become the leading pathophysiological condition of the mitral valve in the developed world. One of the most important causes of regurgitation is prolapse of one of the mitral leaflets. The pathological abnormality that requires repair is rupture or other degenerative changes of the chords, leaflet or other related structures. When the chord(s) remain intact, the mitral leaflets open and close synchronously and in a fashion that prevents leakage of the valve. The normal chords can rupture acutely, causing acute decompensation in the form of heart failure. This usually results in an emergency condition requiring rapid intervention. Damage to the chord(s) can also occur more slowly including rupturing or elongation due to degenerative processes, causing the mitral valve to develop leaks or regurgitation. Surgical repair of the mitral valve has become relatively standardized, using resection of the prolapsed leaflet and / or implantation of new, artificial chordae lines to control leaflet motion. In addition, a mitral ring is frequently placed to shrink the size of the mitral valve annulus. Surgical replacement of ruptured or elongated chords is highly effective in eliminating or minimizing mitral valve regurgitation. The procedure is presently performed with open heart surgery techniques. This requires use of cardiopulmonary bypass and arresting of the heart. This surgical approach, although working well, is a highly invasive procedure which can cause serious complications, long hospital stays and substantial expense. Consequently, a less invasive approach would be preferable. Similarly, a less invasive approach would also be preferable for treatment of the tricuspid valve which, analogously to the mitral valve, may suffer tricuspid valve disease. Insertion of mitral leaflet chords has been done using a minimally invasive surgical approach entering the heart through its apex. The technique, was developed by the company Neochord Inc. and is described, for example, in WO2012 / 167120, but still requires a surgical incision and the chords do not get inserted in the papillary muscles where they normally should be fixed. WO2008 / 101113 describes another example of a system for repair of the heart, including implantation of artificial chordae lines. In the described method an anchor can be attached to the papillary muscle and is coupled to the leaflet of the mitral valve by an artificial chordae line, a suture and a clip. It will be appreciated that this technique, whilst avoiding open heart surgery, still requires a sequence of relatively complex steps. The number of steps required increases the risk. Furthermore, the complexity of the device means that parts implanted within the body are at risk of coming loose and injuring the patient by embolization. In particular, the clip could come loose from the anchors. It is also thought that the use of a suture with an additional clip, as proposed, may not effectively repair the heart valve since it will not closely simulate a natural chord. In an earlier patent application, WO2016 / 042022, the present applicant disclosed a catheter device for implanting an artificial chordae line to repair a heart valve. The catheter device of WO2016 / 042022 includes a mechanical gripper device for grasping the leaflet of the heart valve, with a leaflet anchor housed in the gripper. The leaflet anchor can be formed from a flexible material, such as nitinol, with a grapple hook shape in an unfolded configuration, and being able to deform elastically into the folded configuration, for example when constrained within a leaflet anchor channel in the gripper device. The hooks are straightened out when the leaflet anchor is in the folded configuration. When the leaflet is grasped by the gripper device then the leaflet anchor can be pushed out of the gripper to drive the hooks though the leaflet whilst they return elastically to the unfolded configuration, thereby securing the leaflet anchor in the leaflet. The device described in WO2016 / 042022 also uses a papillary anchor with an arrangement of foldable hooks. The papillary anchor is held within a tube of the catheter device in a folded configuration and can be pushed out of the tube with the hooks being driven into the heart wall whilst they return elastically to the unfolded configuration, thereby securing the papillary anchor to the muscle. The papillary anchor includes a locking ring acting as a locking mechanism for clamping an artificial chordae line when no force is applied. The locking ring maybe elastically deformed to release the line from the locking mechanism for adjustment of the length of the chordae line. In another earlier patent application, WO2020 / 109588, the present applicant disclosed further refinements to the catheter device disclosed in WO2016 / 042022, and new developments related thereto. One area of refinement focussed on the design of the leaflet anchor. The leaflet anchor disclosed therein was designed to increase the surface area of the leaflet anchor in contact with the leaflet upon implantation, and to minimise trauma experienced by the leaflet during implantation. Other anchoring systems are also known from US2009 / 0076547 for example, which discloses a tissue anchor comprising a single elongate strip having folded portions. The elongate strip is delivered from a tubular member passing through the tissue. A suture extends through the elongate strip, and is looped back. Upon the application of tension by the suture, the elongate strip folds around the tissue. Whilst the devices of WO2016 / 042022 and WO2020 / 109588 provided a significant advance in this field, the applicant further developed a new form of anchor suitable for use in mitral valve repair. In WO2023 / 166218, the applicant disclosed an anchor system including a fabric-type arrangement in which two arms of a fabric body pass through body tissue, before collapsing in a concertina-like manner to sandwich the body tissue between the base portion of the fabric body and each arm portion of the fabric body. The use of two arm portions in combination with the base portion provided a greater lateral surface by which to connect the anchor system and the soft body tissue upon implantation. It has been found that further refinement of the design of the new form of anchor may be advantageous. The present disclosure relates to new features building on the design of the device disclosed in WO2023 / 166218 in various respects. It is an objective of the present invention to provide an improved anchor system for implantation in soft body tissue, and more preferably in heart tissue. Viewed from a first aspect of the present invention, there is provided a soft tissue anchor system for implantation in soft body tissue to hold an artificial line, the anchor comprising: a fabric body comprising a base portion and two arm portions extending from the base portion; wherein each arm portion is arranged to collapse towards the base portion such that, in use, the body tissue is sandwiched between the base portion and each of the arm portions; wherein the fabric body is movable between a rest configuration and an implantable configuration; and wherein, in the rest configuration, the two arm portions extend in different respective directions. During implantation of the anchor into soft body tissue, the arm portions generally extend in substantially the same direction for implantation into the soft body tissue for a more stable implantation. To achieve this, fabric bodies have been previously manufactured or cut in a way that presents the arm portions as always extending in substantially the same direction - at rest and during implantation into soft body tissue. However, in doing so, the fibres forming the fabric body can be cut across to achieve the desired footprint for the fabric body. For example, the U-shaped fabric body disclosed in preferred embodiments of WO2023 / 166218 has the arm portions extending in the same direction when the fabric body is both at rest and during implantation. In doing so, the long fibres extending through each arm portion and the base portion are not continuous with one another - the fibres are instead cut across when manufacturing bends and corners, or generally facilitating changes in direction in the footprint of the fabric body, to form the desired the U-shape. By forming the fabric body to have two of the at least two arm portions extend in different respective directions in the rest configuration, the fabric body can be manufactured in a way that keeps the fabric fibres longer - it is no longer necessary to cut across substantially all of the fibres of the fabric material when achieving the desired shape for the fabric body, e.g. due to sharp curves or bends present in the shape of the fabric material. Instead, the fabric body is moved into the implantable configuration to achieve the desired configuration for deployment into the soft body tissue. As such, the fabric body is capable of being formed in a manner whereby the fibres extending along the arm portions and / or the base portion may run continuously or be longer, for a greater proportion of the overall length of the fabric body. The presence of longer fibres can increase the tensile strength of the fabric body, and in turn the strength of the anchor upon implantation in body tissue. Thus, providing a fabric body according to the present invention may improve the strength of the soft tissue anchor. Further, having a fabric body which has fewer, or no, sharp curves or bends present in the shape of the fabric material may be easier to fabricate. The rest configuration will be understood to be a configuration in which the fabric body is at rest. In other words, the fabric body is relaxed or unconstrained, when in the rest configuration. The fabric body may be substantially flat in the rest configuration. The implantable configuration will be understood to be a configuration in which the fabric body is suitable for implantation into soft body tissue. The arm portions will be positioned ready to engage the soft body tissue in the implantable configuration. The arm portions will extend from the base portion in generally the same direction in the implantable configuration. The arm portions may be splayed apart from one another in the implantable configuration. Alternatively, the arm portions may be substantially parallel to one another in the implantable configuration. Preferably, the arm portions will each extend in a respective direction perpendicular to a surface of the soft body tissue, where they are to each be implanted, in the implantable configuration. The fabric body may be arranged to move between the rest configuration and the implantable configuration by bending and / or folding the base portion. Additionally or alternatively, the fabric body may be arranged to move between the rest configuration and the deployable configuration by bending or folding at least one of the arm portions about the base portion. The fabric body may be arranged to move between the rest configuration and the implantable configuration via a stowed, or packed, configuration. In the stowed configuration the fabric body is arranged to be packed into a housing of a catheter device. It will be understood that, unless otherwise specified, the fabric body is not limited to having only two arm portions. In some embodiments, the fabric body has at least two arm portions, and can have more than two arm portions. In the rest configuration, at least two of the at least two arm portions arm portions will extend from the base portion in different respective directions. At least one arm portion and the base portion may be collinear in the rest configuration. Having at least one of the arm portions be collinear with the base portion results in the fibres forming the fabric body and extending along at least one arm portion and the base portion being able to extend continuously for a greater or be longer for a greater proportion of the overall length of the fabric body. The tensile strength of the fabric body may hence be improved. The fabric body may be L-shaped in the rest configuration. The fabric body may comprise only two arm portions extending from the base portion. One arm portion may be collinear with the base portion in the rest configuration. The other arm portion may extend from the base portion in a different respective direction, which may be substantially perpendicular to the base portion and / or the respective direction of the other arm portion. An arm portion and the base portion may be understood to be collinear insofar as the long axis of the arm portion and the width of the base portion, the width being generally coincident with the long axis of the base portion, are collinear with one another. The two arm portions and the base portion may be collinear in the rest configuration. The fabric body may be T-shaped in the rest configuration. The fabric body may comprise (only or at least) three arm portions extending from the base portion. Two arm portions may be collinear with the base portion in the rest configuration. At least one other arm portion may extend from the base portion in a different respective direction, which may be substantially perpendicular to the base portion and / or the respective directions of the arm portions collinear with the base portion in the rest configuration. The fabric body may comprise only the two arm portions. The two arm portions may be collinear, and the fabric body may thus have an elongate form in the rest configuration. The two arm portions will extend from the base portion in opposite directions relative to one another. The fabric body may be regarded as being straight or l-shaped in the rest configuration. By having the fabric body be elongate in the rest configuration, all of its arm portions extend substantially collinearly from the base portion in the rest configuration. Accordingly, the fabric body may be formed in a manner such that a greater proportion of the fibres of its fabric material can extend along substantially the whole length of the fabric body. The tensile strength of the fabric body may thus be improved, since fewer of the fibres of its fabric material are cut short or interrupted by changes in direction of the footprint of the fabric body, along its length. The fabric body may be a tubular fabric body. Forming the fabric body from a tubular fabric material may improve the strength of the fabric body, since the fibres forming the fabric material can run continuously, or for at least a greater proportion uncut or uninterrupted, both along a length of the fabric body and around a circumference of the fabric body. The tubular body may be a flattened tubular fabric body. The fabric body may be double-layered as a result of the flattening of the tubular fabric body. The tubular fabric body may be woven into any of the L-shapes, T-shapes or the like described above. Alternatively, the tubular fabric body may be woven as a continuous tubular, elongate body. The fabric body may comprise a ripstop fabric material. The fabric body may be formed of multiple layers of fabric material. The multiple layers can be stacked on top of one another. Alternatively, the fabric body may be formed of a single layer of fabric material. In this context, a fabric may be considered as a material formed as a weave made of threads or threadlike forms. One possible material is a polyester fabric, other materials include fabrics of PET, UHMPE, EPTFE, PTFE and similar. The fabric body may be formed of any suitable flexible, conformable and biocompatible material. The fabric body may comprise one or more reinforcement fibres woven into its fabric material. The reinforcement fibres may improve the stiffness and / or strength of the fabric material in the direction of the reinforcement fibres. The reinforcement fibres may bend and / or curve along a footprint of the fabric body, and may hence run uninterrupted, or continuously, along substantially the whole length and / or width of the fabric body. As mentioned above, the fabric body comprises two arm portions extending from the base portion, wherein each arm portion is arranged to collapse towards the base portion such that, in use, the body tissue is sandwiched between the base portion and each of the arm portions. By providing a fabric body comprising two or more arm portions extending from the same base, the anchor system may be able to contact a greater surface area of body tissue when implanted, and hence may have improved stability and / or improved tissue ingrowth upon implantation. Further, by providing the collapsible arm portion(s) attached via a base portion, the base portion itself may further be able to provide a greater lateral surface by which to connect the anchor system and the leaflet upon implantation. A soft tissue anchor system, i.e. with at least two arm portions, may provide enhanced performance compared to those having a single arm portion. Accordingly, a soft tissue anchor system as described above may have an improved securement strength compared to known anchor systems comprising a single arm portion and / or fixing member and / or using different design features. Further, the use of a fabric body compared to a rigid body such as a metal body may reduce damage to the body tissue caused by the anchor during and / or after implantation. The fabric may better complement a surface of the body tissue that it contacts, thus spreading force exerted on the body tissue over a greater area and reducing trauma experienced by the body tissue at the site of implantation. It will be appreciated that collapsing of the arm portions toward the base portion can be achieved in various ways, owing to the pliable nature of the fabric body. In a preferred embodiment, the soft tissue anchor system comprises a tension line threaded through the arm portions and the base portion. The tension line is configured to collapse each arm portion in folds towards the base portion when a tensile force is applied to the tension line. Each arm portion may have its own respective tension line, or may share a common tension line. Each tension line could act as implantable chords (i.e. the tension line may be the artificial line). The tension line may be fixed to each arm portion at an end of each arm portion distal to the base portion. Thus, when a tensile force is applied to the tension line, the entirety of the arm portion may be configured to collapse in folds towards the base portion. The location of the threading of the tensile line may facilitate the collapse of the arm portion in folds. For example, as the tension line is pulled, the tension line may draw holes in the arm portion through which the tension line is threaded together. Accordingly, the arm portion may be biased to fold in relation to each location the tension line is threaded through the arm portion. Preferably, the anchor system is configured so that the tensile force is applied to a portion of the tension line(s) threaded through the base portion. This arrangement may facilitate the entire collapse of the arm portions. The tension line may comprise a plurality of bridle lines. Each bridle line is associated with a respective arm portion, and each bridle line is connected to a common bridle point. The bridle point is configured to place each bridle line under tension when a tensile force is applied to the bridle point. That is, the bridle point is configured to apply a tensile force to each of the bridle lines when the bridle point itself is under tension. By providing an arrangement comprising a plurality of bridle lines, each placed under tension due to a common bridle point, the arm portions (and / or end caps, if present) of the soft tissue anchor may each experience a tensile force pulling them towards a plane or axis intersecting the bridle point and in the direction of the tensile force applied to the bridle point. This may result in each of the arm portions being motivated towards one another, and in turn capturing, gathering and / or pinching together any excess body tissue located between the arm portions upon implantation. Accordingly, this arrangement may restore the shape of the soft body tissue and / or provide additional structural support to the body tissue. The arrangement comprising a plurality of bridle lines each connected to a common bridle point may be particularly advantageous when the soft body tissue is a heart valve leaflet. The reshaping of the tissue of the leaflet resulting from capturing excess leaflet tissue as described above has been found to provide an outcome similar to resection of the leaflet. Resection is a common surgical step in existing methods of heart valve repair, in which a surgeon resects a damaged section of the heart valve and stitches the edges of the remaining tissue together. Resection is often performed where there is excessive leaflet tissue present. However, by providing a line arrangement comprising a bridle point and a plurality of bridle lines, the need for a resection step may be obviated. This could simplify the overall surgical procedure. In the described embodiment, the line may be considered to be a bridle arrangement, wherein the bridle arrangement comprises a plurality of bridle lines. Each bridle line will be threaded through each of the arm portions and the base portion (and an end of each bridle line may be fixed to a respective end cap), with each bridle line configured to collapse each arm portion in folds towards the base portion when a tensile force is applied to the bridle line by the bridle point. Each bridle line will be connected to the bridle point at a location on an opposite side of the base portion to the arm portions. The bridle point may be a fixed bridle point such that the bridle lines cannot move relative to the bridle point at the connection. The bridle point may be a fixed knot, an eye plate or other suitable fastening. Alternatively, the bridle point may be a slidable bridle point such that the bridle lines can move relative to the bridle point at the connection. The bridle lines may self-adjust, in a manner as described above. The bridle point may be a bridle knot, with a single, mutual line providing multiple bridle lines. The artificial line may be connected to the bridle point, and may be configured to apply a tension force to the bridle point, i.e. place the bridle point under tension. The artificial line may form one of the bridle lines. The remaining bridle lines may be joined to the artificial line at the bridle point, located along the artificial line. The bridle point is preferably arranged to provide each of the plurality of bridle lines on a first side of the bridle point, with a single tension and / or artificial line located on a second side of the bridle point opposite the first side. Such a configuration may provide a more stable distribution of tensile force from the bridle point to each of the bridle lines. The plurality of bridle lines may consist of two bridle lines, in which case the bridle arrangement may comprise a Y-shaped configuration. The plurality of bridle lines may consist of three bridle lines, in which case the bridle arrangement may comprise a trident-shaped configuration. The soft tissue anchor system may comprise the artificial line. The artificial line may be configured to apply the tensile force to the tension line. The artificial line may be joined to the fabric body via the base portion, using any suitable fastening arrangement. The tension line and / or the artificial line may be formed of a suture material. Each arm portion comprises an end cap fixed at an end of each arm portion distal to the base portion. Each end cap comprises an opening configured to engage a wire guide member for implanting the fabric body in the body tissue. By providing end caps comprising openings configured to engage a wire guide member for implanting the fabric body, the arm portions may be manipulated such that they can be implanted through the body tissue. For example, the wire guide members can push the arm portions in a direction of their engagement such that the arm portions pass through the body tissue. Further, by using wire guide members which guide the arm portions through the body tissue, rather than a needle from which the arm portions are deployed, a hole in the body tissue through which each arm portion is passed need not be as large as a hole required by a needle or other conduit containing the arm portions to pass through. That is, the size of the openings is constrained by no more than the geometry of the fabric body. In comparison, the size of openings which are required for implantation via a needle will always be constrained by the size of the needle which is always larger than the member it is to deploy. This may reduce trauma at the site of implantation. The anchor system may comprise a tension line (e.g. as described above). The tension line may be fixed to the end cap and extends from a central portion thereof such that, in use, the end cap is configured to extend in a plane parallel to a surface of the body tissue when implanted in the soft body tissue and under tension of the line when it is passing through the tissue in a direction away from the surface thereof. Each end cap comprises an outer tubular member and an inner tubular member, wherein the outer tubular member is configured to receive the inner tubular member. The inner tubular member defines the opening configured to engage the wire guide member. The outer tubular member and the inner tubular member may be configured to sandwich, crimp and / or clamp the distal end of a respective arm portion therebetween, thereby fixing the end cap to the arm portion. Adhesives may be additionally or alternatively employed, to fix the end cap to the arm portion. In one arrangement, the outer tubular member and the inner tubular member each define openings extending along the entirety of their length, i.e. they are hollow along the entirety of their length. The inner tubular member may be configured to allow passage of a piercing section of the wire guide member therethrough, and may also be configured to abut a shoulder portion, or bulge portion, of the wire guide member. A wire guide member comprising a piercing section, which is configured to pierce the body tissue during implantation of the anchor system, may be regarded as a piercing wire guide member. By enabling passage of the piercing wire guide member through the inner tubular member, the end cap may comprise a dulled and / or rounded tip whilst still enabling piercing of the body tissue during implantation of the anchor system. Further, by providing an inner tubular member configured to abut a shoulder portion, or bulge portion, of the wire guide member, suitable contact for manipulation of the arm portions via the piercing wire guide member may be realised. Moreover, the use of end caps which are suitable for use with a piercing wire guide member may further reduce trauma experienced by the site of implantation, because the piercing section of the wire guide member may have a smaller diameter than, for example, a hollow needle member making the incision for implantation. The outer tubular member may comprise a tapered portion located at the tip of the end cap. That is, the tip of the end cap may be defined by the outer tubular member and an end of the inner tubular member may be contained within the outer tubular member. This arrangement results in a continuous transition located at the tip of the end cap between the tip of the end cap and the outer tubular member, which may facilitate smoother passage of the end cap through the body tissue during implantation. The inner tubular member may comprise a flared inlet defining the opening configured to engage the wire guide member. The flared inlet will be understood to be a portion of the inner tubular member defining the opening, wherein a circumferential extent of the inner tubular member is increased relative to the rest of the inner tubular member. The flared inlet may be configured to mate with a corresponding portion of the wire guide member. That is, the flared inlet may be complementary to a shape of the shoulder region, or bulge portion, of the piercing wire guide member. The angled face of the flared inlet may be complementary to the shoulder region, or bulge portion, of the wire guide member. The flared inlet may improve contact between the wire guide member and the end cap during implantation of the fabric body. Each end cap may comprise a pointed tip. The pointed tip may be configured to pierce the body tissue and, for example, the pointed tip may pierce the body tissue when a motive force is applied to the end cap by the wire guide member. The outer tubular member may define the pointed tip. The outer tubular member may comprise an opening formed in a side wall, the opening configured to receive the tension line. Each end cap may be configured to receive the tension line between the inner tubular member and the outer tubular member. The tension line may be fixed to each end cap by crimping, swaging, clamping, gluing and / or sandwiching the tension line between the inner tubular member and the outer tubular member. The tension line could also be fixed by stitching it or tying it to the tubular member. The outer tubular member of each end cap may comprise a groove, channel, aperture or other suitable feature for guiding the arm portions between the outer tubular member and the inner tubular member. This groove, channel, aperture or other suitable feature may be formed in circumferential alignment with the aperture, or opening, for the line, and may also be formed at or towards the opening configured to receive the wire guide member. Providing the line and the arm portion in alignment with one another may improve the stability of the soft tissue anchor system when implanted in soft body tissue. The base portion may define a maximum width of the fabric body in the deployable configuration. The base portion may comprise a pair of wing portions. The wing portions may extend wider than an outermost edge of the arm portions. By providing a base portion of increased width, or at least greater width than compared to the arm portions, the base portion may be configured to provide greater lateral support to the fabric body upon implantation in the body tissue. When the anchor is in use then the base portion may be implanted on the atrial side of the leaflet, where the retention is required during a heartbeat. In this context an increased lateral support for the atrial side location can be beneficial to achieve a wide area of support of the leaflet. If the base portion is at the atrial side then the arm portions are on the ventricle side. They act to hold the anchor system in place and provide some support, while the atrial side portion (base portion) is more active in carrying forces exerted by blood flow on the leaflets during heart contraction (systole). The base portion may comprise a shape retention member. The shape retention member may be configured to increase a stiffness of the base portion. The shape retention member may be configured to maintain a planar extent of the base portion, or a 3D shape that conforms with the shape of the leaflet / anatomy. By stiffening the base portion using a shape retention member, the base portion may be able to provide greater lateral support to the body tissue in which the fabric body is implanted. Further, tensile forces experienced by the fabric body during implantation when holding the artificial line, may be more evenly distributed across the base portion when a shape retention member is provided. This may improve the stability of the fabric body upon implantation. The shape retention member may be formed of an elastic material. The base portion may comprise a folded configuration and an unfolded configuration, wherein the shape retention member is configured to urge the base portion from the folded configuration to the unfolded configuration upon removal of a constraining force. The base portion may be substantially planar in the unfolded configuration. The shape retention member may be embedded, interwoven with, and / or sandwiched between layers of, the base portion. The base portion may be formed by folding a portion of the fabric body back over on itself, and sandwiching the shape retention member therebetween. The shape retention member and / or the folded portion of the fabric body may be fixed in place by an adhesive, ultrasonic welding, stiches or other suitable fixing means. The shape retention member may be formed of a shape retention metal such as stainless steel, titanium or nitinol. The shape retention member may be formed by laser cutting, or by shaping a wire formed of a similar material. The fabric body may comprise a narrow waist portion extending between the base portion at least one of the arm portions. Upon implantation, the narrow waist portion may be aligned with the soft body tissue such that the narrow waist portion is encircled by the soft body tissue at the implantation site. The narrow waist portion may be configured to be longer than a thickness of the soft body tissue in which the soft tissue anchor system is to be implanted. For example, a length of the narrow waist portion may be: greater than at least 1mm; greater than at least 2mm; or greater than at least 3mm. The length of the narrow waist portion may be between 1 and 3 mm. Each narrow waist portion may equally be considered as part of a respective arm portion, such that the arm portions each comprise a narrow waist portion at an end of the arm portion proximal to the base portion, or alternatively may be considered its own respective portion as described above. The narrow waist portions may stabilise the implantation of the base portion adjacent to the body tissue. This feature also may aid in holding the arm portions in place prior to tensioning the tension line. The fabric body may comprise a bulged portion extending between the base portion and at least one of the arm portions. The bulging portion is wider than the arm portion, and thus when the arm portion is implanted in the soft body tissue may act to prevent movement of the arm portion through the soft body tissue. Preferably, the bulging portion is pushed through the soft body tissue during implantation. Then, the addition of the bulging portion can resist the arm portion being pulled back through the soft body tissue when implanted. Alternatively, the bulging portion may be arranged to abut the soft body tissue and prevent the fabric body being inserted too far or deeply through the soft body tissue. The fabric body may comprise two bulged portions extending between the base portion at least one of the arm portions. The bulged portions may be arranged to sandwich the soft body tissue therebetween, upon implantation. A first bulged portion may be arranged to abut a first surface of the soft body tissue, and a second bulged portion may be arranged to be passed through the soft body tissue and be located adjacent to a second surface opposite the first. In this way, the two bulged portions may sandwich the soft body tissue. The fabric body may comprise a narrow waist portion and a bulged portion. The soft tissue anchor system may be a leaflet anchor system for implantation in a heart valve to hold an artificial chordae line. The heart valve leaflet may be a mitral valve leaflet or a tricuspid valve leaflet. Viewed from a second aspect of the present invention, there is provided a catheter device for implanting a soft tissue anchor system in heart tissue. The catheter device comprises: a housing section, wherein the housing section extends from a distal end of the catheter device along the length of the catheter device toward a proximal end of the catheter device; and a soft tissue anchor system according to the first aspect located within the housing section. The catheter device of the second aspect may have one or more features corresponding to those of the soft tissue anchor systems of the first aspect of the invention. Thus, the above-description of the soft tissue anchor system of the first aspect, including but not limited to all technical advantages and alternative embodiments, may be equally applicable to the catheter device of the second aspect. The catheter device may comprise a leaflet anchor for placement in a leaflet of a heart valve, wherein the leaflet anchor is the soft tissue anchor system, wherein the leaflet anchor is arranged to be coupled to the artificial line; and a leaflet anchor deployment mechanism for deploying the leaflet anchor to attach it to the leaflet of the heart. The catheter device may comprise a wire guide member(s) for deploying the soft tissue anchor system from the housing section. Where the soft tissue anchor system comprises end cap(s), the catheter device may comprise a wire guide member(s) in engagement with the opening. The wire guide member may comprise a shoulder portion. The housing section may comprise a stopping portion configured to mate with the shoulder portion and thereby limit a distal translation of the wire guide member in the housing section. The catheter device may comprise a mechanical gripper device for grasping the leaflet of the heart valve; and a leaflet anchor tube for housing the leaflet anchor before deployment into the body tissue. The gripper device and the leaflet anchor may be arranged such that when, in use, the gripper device grasps the leaflet, the leaflet anchor system can be pushed out of the leaflet anchor tube to pierce the leaflet and deploy the anchor such that it is implanted in the leaflet. The leaflet anchor deployment mechanism may comprise the mechanical gripper device and the leaflet anchor tube. The leaflet anchor deployment mechanism may also comprise the wire guide member(s). The wire guide member(s) may deploy the leaflet anchor from the leaflet anchor deployment mechanism. The mechanical gripper device may include a gripper arm rotatably coupled to a main body of the catheter device so that the gripper arm can rotate relative to the catheter device to move an outer end of the gripper arm away from the main body of the catheter device. The leaflet anchor tube may be formed in the main body of the catheter device. The leaflet anchor may thus be configured to be deployed from the main body of the catheter device and towards the gripper arm grasping the leaflet. In example embodiments the leaflet anchor tube is arranged to implant the leaflet anchor in the leaflet of the heart by piercing the leaflet from an atrial side of the leaflet. The leaflet may be a mitral valve leaflet or a tricuspid valve leaflet. The catheter device may comprise a papillary anchor arranged to be coupled to the artificial line at a distance from the leaflet anchor. The catheter device may comprise a papillary anchor deployment mechanism for deploying the papillary anchor to attach it to papillary muscle of the heart. The papillary anchor may have a chordae line attached to it, and may include a locking mechanism, such as a locking ring as in WO2016 / 042022 or in WO2020 / 109596, the locking mechanism being for clamping the chordae line when no force is applied to the locking mechanism. The locking ring may be able to be elastically deformed to release the line from the locking mechanism for adjustment of the length of the chordae line. The papillary anchor deployment mechanism may include a locking ring holder for holding the locking ring in its elastically deformed position, with the papillary anchor deployment mechanism being arranged to selectively withdraw the locking ring holder from the locking ring so that the chordae line can be locked in place after deployment of the papillary anchor and after any required adjustment of the length of the chordae line. Where each arm portion comprises its own respective tension line, each tension line may itself act as an artificial chord. Each respective line may extend between the leaflet anchor and the (i.e. the same, common) papillary anchor. Each respective line may be received through the locking mechanism of the papillary anchor. In this way, the locking mechanism may be arranged to clamp each respective tension line when no force is applied to the locking mechanism. By using the locking mechanism to hold each respective line in place, there may be no need for a bridle point or the use of a bridle line arrangement. The tension in each respective line may be independently adjusted to achieve the desired level of tension in each line. The locking mechanism may be used to clamp each respective line at the desired length, such that the appropriate amount of tension is applied to the respective line. The catheter device may comprise a wire guide member(s) for deploying the soft tissue anchor system from the housing section. Where the soft tissue anchor system comprises end cap(s), the catheter device may comprise a wire guide member(s) in engagement with the opening. The wire guide member may comprise a shoulder portion. The housing section may comprise a stopping portion configured to mate with the shoulder portion and thereby limit a distal translation of the wire guide member in the housing section. The housing section may be a two-part housing section. The catheter device may comprise: the two-part housing section extending from the distal end of the catheter device along the length of the catheter device toward the proximal end of the catheter device, the two-part housing section comprising a distal part at the distal end of the catheter device and a proximal part located on the proximal side of the distal part; the leaflet anchor deployment mechanism being at the proximal part of the housing section; a papillary anchor deployment mechanism at the distal part of the housing section for deployment of a papillary anchor for attachment to the papillary muscle, wherein the papillary anchor deployment mechanism is arranged for deployment of the papillary anchor by moving it outward in the distal direction relative to the distal part; and a flexible joint located between the proximal part and the distal part of the two-part housing section, wherein the flexible joint allows a centreline of the distal part to be angled relative to a centreline of the proximal part. The two-part housing section may be arranged to be coincidentally placed between the papillary muscle and a leaflet of the heart during use of the catheter device. The gripper arm may be provided in the proximal part of the two-part housing section and may be rotatably coupled to the catheter device. The flexible joint may include a hinge element, for example with the distal part of the two-part housing section coupled to the proximal part via a pivoting mechanism or via an elastically deformable element. For example, the two parts of the housing section may be composite or metal parts coupled together by the hinge element. The papillary anchor may be housed within the distal part of the housing section before its deployment. The papillary anchor may have a similar cross-section as the distal part of the housing section. For example, both may have a tubular form when the anchor is held in the distal part. As noted above the anchor may have a folded and an unfolded configuration allowing pins of the anchor to form into hooks within the body tissue during deployment of the papillary anchor. The papillary anchor deployment mechanism may take a similar form to that of WO2016 / 042022 or WO2020 / 109596. Viewed from a third aspect of the present invention, there is provided a method of manufacturing the soft tissue anchor system according to the first aspect. The method comprises: fabricating the fabric body; and configuring each arm portion to collapse. The method of the third aspect of the invention may have one or more features corresponding to those of the soft tissue anchor system of the first aspect of the invention. Thus, the above-mentioned description of the soft tissue anchor system of the first aspect, including but not limited to all technical advantages and alternative embodiments, may be equally applicable to the method of the third aspect. The step of fabricating the fabric body may comprise laser cutting a fabric. The step of fabricating the fabric body may comprise punch cutting the fabric body from a sheet of fabric. The fabric may be selected from the group consisting of: polyester; PET; UHMPE; EPTFE; PTFE or the like. Fabricating the fabric body may comprise weaving, knitting, and / or crocheting a fabric into a desired shape for the fabric body. Other similar techniques are also contemplated. The fabric body may be fabricated using one or more long, uninterrupted (i.e. uncut) fibres extending along the length of at least one arm portion and the base portion. Using uninterrupted fibres extending along the length of at least one arm portion and the base portion can increase the strength of the fabric body and reduce possible points of failure, e.g. due to unwinding starting from free ends of cut, interrupted fibres. Fabricating the fabric body may comprise weaving one or more reinforcement fibres into the fabric body. Configuring each arm portion to collapse may comprise threading a tension line through the arm portions and the base portion. Viewed from a fourth aspect of the present invention, there is provided a method of implanting a soft tissue anchor system according to the first aspect. The method comprises: moving the fabric body into the implantable configuration; pushing each arm portion through the body tissue; and collapsing each arm portion towards the base portion such that the body tissue is sandwiched between the base portion and each of the arm portions. The method of the fourth aspect of the invention may have one or more features corresponding to those of the soft tissue anchor system of the first aspect of the invention. Thus, the above-mentioned description of the soft tissue anchor system of the first aspect, including but not limited to all technical advantages and alternative embodiments, may be equally applicable to the method of the fourth aspect. The method may comprise engaging each arm portion using a respective wire guide member; wherein the step of pushing each arm portion through the body tissue is performed using the respective wire guide member. The respective wire guide members may be used to move the fabric body into the implantable configuration. Moving the fabric body into the implantable configuration may comprise folding the base portion and / or folding at least one of the arm portions about the base portion. It will be readily appreciated that the fabric body does not need to be moved into the implantable configuration directly from the rest configuration. For example, the fabric body could move from the rest configuration to the implantable configuration via an intermediate configuration, e.g. when packed in a housing of a catheter device ready for deployment into the soft body tissue. Certain example embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings, in which: Figures 1A-G illustrate respective steps of a procedure for implanting an anchor to hold a line in soft body tissue using a catheter device; Figure 1H shows a pair of soft tissue anchors holding a line, after implantation; Figure 11 shows a soft tissue anchor during its implantation in soft body tissue; Figure 1J shows an implanted soft tissue anchor in soft body tissue; Figure 1K illustrates an end cap for a soft tissue anchor; Figure 1L shows a fabric body of a soft tissue anchor system packed in a housing of a catheter device; Figure 2 is a plan view of a soft tissue anchor in a rest configuration; Figure 3 is a perspective view of the soft tissue anchor of figure 2 in an implantable configuration; Figure 4A is perspective view of a soft tissue anchor during implantation in soft body tissue; Figures 4B and 4C are perspective views of the soft tissue anchor of figure 4A implanted in soft body tissue; Figure 5 illustrates an alternative form of fabric body for a soft tissue anchor; Figure 6 illustrates a tubular fabric body for a soft tissue anchor; and Figure 7 illustrates another alternative form of fabric body for a soft tissue anchor. The following description details one or more features consistent with, and combinable with, the aforementioned description of the anchor system. The following embodiments herein discussed are not to be viewed in isolation and are not intended to be restrictive, but are to be viewed in the context of the present disclosure as a whole, also considering the appended figures. The soft tissue anchor systems and catheter devices presented herein are proposed for non-surgical (endovascular) insertion of mitral chords to address mitral valve regurgitation caused by prolapse of a leaflet of a heart valve. Figures 1A-1L illustrate a form of catheter device 2 for the purpose of treating mitral valve regurgitation by implanting a soft tissue anchor system 100, which is a leaflet anchor, and a papillary anchor 9 in heart tissue to secure an artificial chordae line 14 in the heart. The artificial chordae line 14 is fixed to the prolapsing leaflet 12 and to the papillary muscle 26, thereby recreating a normal anatomy. The general procedure for using such a catheter device is summarised as follows, with reference to figures 1A-1G: 1) The femoral vein is entered using standard Seidinger technique and the guiding catheter introduced. 2) The guiding catheter 22 is advanced to the right atrium RA under x-ray guidance. 3) The left atrium LA is entered after penetration of the atrial septum, guided by x-ray and transesophageal echo (see figure 1A). 4) Correct position of the entrance site in the left atrium LA is verified to assure proper alignment for insertion of the guiding catheter 22 and the treatment catheter 2. The entrance hole in the atrial septum is dilated and the guiding catheter 22 is advanced into the left atrium LA. 5) A treatment catheter device 2 is advanced through the guiding catheter 22 and positioned in the left atrium l_A above the mitral valve. 6) The prolapsing segment of the mitral leaflet 12 is located with ultrasound and the treatment catheter device 2 is advanced into the left ventricle LV, placing a gripper device 6 of the treatment catheter device 2 in position to grip the prolapsing segment (see Fig. 1B). 7) The prolapsing segment is gripped (see figure 1C) and after assuring correct position a leaflet anchor 100 is deployed into the leaflet 12 by pushing arm portions 104 through the leaflet 12 using wire guide members 118 (see figure 1D). 7A) With the arm portions 104 of the leaflet 12 pushed through the leaflet 12, the gripper device 6 can release the leaflet 12 at this stage (it can otherwise be released later, as described below). 8) The wire guide members 118 are retracted, leaving the arm portions 104 extending through the leaflet 12 (see figure 1E). The arm portions 104 are then collapsed towards the leaflet 12, securing the leaflet anchor 100 in place. 8A) If the gripper device 6 has not already released the leaflet 12, the gripper device 6 now releases the leaflet 12. 9) The catheter device 2 is advanced further into the left ventricle LV. 10) A distal end of the catheter device 2 is placed against the papillary muscle 26, and the papillary anchor 9 is pushed out from the catheter device 2 and engages with the papillary muscle 26 (see figure 1F). 11) The catheter device 2 is withdrawn from the left ventricle LV, leaving behind an adjustment catheter 21 engaged with the papillary anchor 9 (see figure 1G). The length of the artificial chordae line 14 is adjusted until mitral regurgitation is eliminated. Elimination of mitral regurgitation is confirmed by echocardiography. 12) The position of the artificial chordae line 14 is locked at the papillary anchor 9. 14) The excess chordae line 14 is cut, and the papillary anchor holder 90 releases the papillary anchor 9. 15) Additional artificial chordae lines 14 may be placed if necessary. 16) The catheter device 2 is fully withdrawn and removed from the vascular system, leaving the implanted anchors 9, 100 securing the artificial chordae line(s) 14 in place (see figure 1H). As described above, a single catheter device 2 is used to implant both the leaflet anchor 100 and the papillary anchor 9 in the heart tissue. The length of the chord 14 can be adjusted, again using the same catheter device 2, to eliminate mitral regurgitation. Thus, such a catheter device 2 enables a single minimally invasive endovascular procedure to be used to repair the mitral valve, providing significant advantages compared to earlier systems requiring more invasive procedures and / or multiple operations. It should be noted that although an endovascular approach is preferred and the catheter device 2 is hence capable of using this approach, the device 2 could of course be used in different procedures, including more invasive procedures. Many of the advantages will remain, and it could be beneficial to use this device in situations where a more invasive procedure is merited. In addition, it is contemplated that, as discussed above, aspects of the catheter device 2, and the design of the papillary anchor 9 or the soft tissue anchor system 100, could be used for other purposes and this disclosure is not intended to be limited in this regard. The catheter device 2 and the soft tissue anchor system 100 may also have one or more or all of the features and technical advantages described in WO2016 / 042022, WO2020 / 109588, and WO2020 / 109588. The skilled person will readily appreciate how like elements may be substituted or incorporated into the catheter device 2 and soft tissue anchor systems 100 described herein. The contents of WO2016 / 042022, WO2020 / 109588, and WO2020 / 109588, are hence incorporated herein by reference in their entirety. The main features of the catheter device 2 and the soft tissue anchor system 100 illustrated in figures 1A-K will now be described in detail. The catheter device 2 includes a housing that houses the papillary anchor 9 and the soft tissue anchor system 100. The housing is a two-part housing comprising a proximal part 4 and a distal part 8. The proximal part 4 houses the soft tissue anchor system 100, whilst the distal part 8 houses the papillary anchor 9. The two-part housing is jointed by a hinge joint 32 between the proximal part 4 and the distal part 8. The joint 32 enables relative movement between the proximal and distal parts 4, 8 of the housing, in order to control relative positioning of the respective anchors 9, 100 of the catheter device 2. As shown in figure 1F, by being able to angle the distal part 8 relative to the proximal part 4, a distal end of the catheter device 2 can be properly positioned relative to the papillary muscle 26 to ensure a reliable and stable delivery of the papillary anchor 9 into the papillary muscle 26. Preferably, the distal part 8 will be oriented substantially perpendicular to a surface of the papillary muscle 26 at the location of implantation of the papillary anchor 9. The catheter device 2 also includes a gripper device 6, which is a means for temporarily holding, or connecting to, the mitral leaflet 12. By grasping the leaflet 12 in preparation of and during implantation of the leaflet anchor 100, the leaflet 12 can be stabilised and prevented from flailing during the implantation process. This can improve the accuracy and reliability of the implantation of the leaflet anchor 100 in the leaflet 12. The gripper device 6 comprises a gripper arm 30 rotatably coupled to the catheter device 2. The gripper arm 30 rotates away from the housing of the catheter device 2 to capture the leaflet 12 (see figure 1B), and rotates back towards the housing of the catheter device 2 to grasp the leaflet between itself and the proximal part 4 of the housing (see figure 1C). The papillary anchor 9 is shown in figure 1H. The papillary anchor 9 comprises a plurality of hooks 62 used to engage the papillary muscle 26, and a locking mechanism 28 used to attach the artificial chordae line 14 to the papillary anchor 9. The papillary anchor 9 is formed of an elastic material such as stainless steel or nitinol. The hooks 62 have a folded configuration and an unfolded configuration. The hooks 62 will be in the folded configuration when constrained by, and held in place within, the distal part 8 of the two-part housing. The hooks 62 will unfold as the papillary anchor 9 is ejected from the distal part 8 of the two-part housing, and into the papillary muscle 26, thereby engaging the papillary muscle 26. The hooks 62 have a curved shape when unfolded. Openings 64, e.g. in the form of slits, are formed extending along the hooks 62. The locking mechanism 28 has an open configuration and a closed configuration. In the open configuration, the artificial line 14 is able to slide through the locking mechanism 28 so that its length can be adjusted. In the closed configuration, the artificial line 14 is trapped in place by the locking mechanism 28 thereby fixing the artificial line to the papillary anchor 9. The locking mechanism 28 is formed of a pair of parallel slits, integrally formed in a wall 60 of the papillary anchor 9. The parallel slits are deformed out of the plane of the wall 60 of the papillary anchor 9 upon application of a force, to move the locking mechanism 28 into the open configuration. When no force is applied, the locking mechanism 28 is in the closed configuration and is capable of clamping the line 14. The anchor holder 90 (see figure 1G) can be used to hold the locking mechanism 28 in the open configuration during adjustment of the line. A non-circular cross-section formed by the locking mechanism 28, and / or a non-circular cross-section of the anchor holder 90, can mate with a non-circular cross-section of the distal part 8 of the housing, thereby restricting rotation of the papillary anchor 9 when housed and during its implantation into the papillary muscle. The soft tissue anchor system 100 is shown in further detail in figures 11, 1J and 1K. The soft tissue anchor system 100 can be a leaflet anchor for implantation in a heart valve leaflet to hold an artificial chordae line 14, as described above. However, it will be readily appreciated that the soft tissue anchor 100 need not be limited to this purpose alone. The soft tissue anchor system 100 is a fabric-type arrangement formed of a fabric body 101. The fabric body 101 comprises a base portion 102 and two arm portions 104 extending from the base portion. The fabric body 101 can be described as ‘U-shaped’. Each arm portion 104 is arranged to collapse towards the base portion 102, such that the soft body tissue 12 can be sandwiched between each arm portion 104 and the base portion 102. Soft tissue anchor systems 100 comprising a plurality of arm portions 104 connected by a single base portion 102 may increase a surface area of the anchor system 100 engaged with the soft body tissue 12, on both sides of the body tissue. This may improve the stability of the anchor system 100 when implanted in body tissue. The fabric body 101 is used to anchor the artificial chordae line 14, located towards the base portion 102, to the body tissue 12. Being a fabric body 101, it will be understood that the fabric body 101 is primarily formed of a soft material. The fabric body 101 also comprises a tensile line 14’. Each arm portion 104 comprises a portion of tensile line 114’ threaded through the arm portion 104 and the base portion 102, the threading running from an end of the arm portion 104 distal to the base portion 102, to the base portion 102. Each portion of tensile line 14’ is fixed towards the distal ends of the arm portions 104, but is otherwise free to move with respect to threaded holes formed along the arm portions 104 and in the base portion 102. The artificial chordae line 14 can be joined to the tensile line 14’ via any suitable fastening means 115, such as a knot or an eyelet. Preferably, the fastening means 115 is a bridle knot. In other embodiments, the artificial chordae line 14 and the tensile line 14’ can be portions of the same line. Each arm portion 104 is configured to collapse in folds towards the base portion 102, by action of the tensile line 14’ threaded through the arm portions 204. That is, the tensile line 14’ can collapse the arm portions 104 in folds towards the base portion 102 when a tension force is applied to the tensile line 14’. In other words, the tensile line 14’, threaded through the arm portions 104, is an example of a means for collapsing each arm portion 104 in folds towards the base portion 102 such that, in use, the body tissue is sandwiched between the base portion 102 and each of the arm portions 104. As the U-shaped fabric body 101 is formed of a primarily soft material, actuation of the tensile line 14’ from an end distal to where the portions of line 14’ are fixed to the arm portions 104 results in the arm portions 104 collapsing in a concertina fashion (i.e. collapsing in folds towards the base portion 102). Also located at the ends of the arm portions 104 distal to the base portion 102 are end caps 108. The end caps 108 are rigid structures which aid implantation of the fabric body 101 in the body tissue, and also assist in maintaining engagement of the fabric body 101 to the body tissue. Each end cap 108 comprises an opening 110 for receiving a wire guide member 118, as will be discussed in detail further below. The wire guide members 118 are used for implanting the anchor system 100, and may facilitate ease of implantation. Figure 11 shows the soft tissue anchor system 100 during implantation in the mitral valve leaflet 12 of the heart (see also figure 1D). To implant the fabric body 101, a pair of wire guide members 118 are employed. The wire guide members 118 are each received by respective openings 110 of the end caps 108, and are used to push the end caps 109 into a piercing engagement with the leaflet 12. During implantation and when the wire guide members 118 are engaged with the end caps 108, the end caps 108 extend collinearly with the arm portions 104. The wire guide members 118 then push the end caps 109 through the leaflet 12, thereby pulling the arm portions 104 through the leaflet 12, such that the fabric body 101 engages the leaflet 12. As shown in figure 1H, the base portion 102 of the fabric body 101 is arranged to contact an atrial surface 12a of the leaflet 12 upon implantation. Once the fabric body 101 is implanted in the leaflet 12, the wire guide members 118 are retracted (see figure 1E). As shown in figure 1 J, with the arm portions 104 implanted in the leaflet 12, the arm portions 104 can then collapse towards the base portion 102, such as in folds under tension of the line 14’. Withdrawal of the wire guide members 118 may result in the end caps 108 returning to an orientation perpendicular with the arm portions 104 at rest, or parallel to a plane of the folds of the arm portions 104 when the arm portions are collapsed 104 (see also figure 1F). Figure 1K shows a cross-section of the end cap 109. The end cap 109 has a two-part construction, and is formed of an outer tubular member 108a and an inner tubular member 108b. The outer tubular member 108a comprises a pointed tip 109, an opening 111 for receiving the tension line 14’, and a notch 112 for receiving an end of the arm portion 104 of the fabric body 101. The inner tubular member 108b is nested within the outer tubular member 108a, and comprises a flared inlet 108c defining an opening 110 for receiving the wire guide member 118. The tension line 14’ and the arm portion 104 are held in place between the outer tubular member 108a and the inner tubular member 108c, and are maintained in place by crimping the outer tubular member 108a. The outer tubular member 108a is configured to retain the inner tubular member 108b via a press fit. An end of the inner tubular member 108b distal to the flared inlet 108c is configured to mate with a complementary notch of the outer tubular member 108a, such that the inner tubular member 108b is retained via an interference fit. Additionally, the flared inlet 108c of the inner tubular member 108b is arranged to abut an inner wall or surface of the outer tubular member 108a, thereby again reinforcing the press fit mating. As shown in figure 1K, the wire guide member 118 can comprise a dulled tip used to push the end cap 109 into the soft body tissue 12. The pointed tip 109 of the end cap 108 is then solely used to pierce the soft body tissue 12. Alternatively, as shown in figure 11, the wire guide member 118 can pass through the end cap 108. A piercing tip of the wire guide member 118 is then used to pierce the soft body tissue 12, whilst a thicker section of the wire guide member 118 located behind the piercing tip is used to push the end caps 108 through the soft body tissue 12 (see also figure 1D). In other arrangements (not shown), each arm portion 104 comprises its own respective line 14’ that may act as an artificial chord 14. For a fabric body 101 having two arm portions 104, the soft tissue anchor system 100 hence comprises two artificial lines 14. In this arrangement, the locking mechanism 28 of the papillary anchor 9 receives both artificial lines 14, and clamps each line 14 when no force is applied. In this arrangement, since the lines 14 are not common with one another or attached at a bridle point 15, the tension in each line 14 can be adjusted by clamping each line 14 at different lengths in the locking mechanism 28. This can enable an operator to more freely adjust the tension in each line 14. Figure 1L shows the soft tissue anchor system 100 packaged in the proximal part 4 of the housing of the catheter device 2. The fabric body 101 is packed into the space provided in the proximal part 4 of the housing. Channels 18 are provided for the end caps 108, and for the wire guide members 118 to pass through. These channels 18 are open to the space into which the bulk of the fabric body 101 is stowed. The stowing of the fabric body 101 and packing of its arm portions 104 in the space provided can be likened to the packing of a parachute and its lines into a parachute rig. When packed into the proximal part 4 of the housing, the fabric body 101 is deployable insofar as, when the wire guide members 118 engage each respective arm portion 104, the arm portions 104 unfurl and extend away from the base portion 102 in the manner illustrated in figure 11. With the arm portions 104 extending away from the base portion 102, and ready to engage the leaflet 12, the fabric body 101 can be considered to be in an implantable configuration in which the arm portions 104 are suitable for engaging the leaflet 12. When the wire guide members 118 are withdrawn and the arm portions 104 are collapsed under tension of the line 14’, the fabric body 101 can be considered to be in an implanted, or deployed, configuration. As mentioned above, embodiments of the present invention pertain to soft tissue anchor systems as now described herein. The soft tissue anchor systems described herein can be used in the catheter device 2 of the type described above in connection with figures 1A-K. It will also be readily appreciated that the soft tissue anchor systems now described herein may have one or more features in common with the soft tissue anchor system 100 described above. Figure 2 shows a soft tissue anchor system 200 in a rest configuration. The soft tissue anchor system 200 has a fabric body 201, a base portion 202, and two arm portions 204 extending from the base portion 202. As with the soft tissue anchor system 100 described above, the arm portions 204 are arranged to collapse towards the base portion 202 such that, in use, soft body tissue 12 can be sandwiched between the base portion 202 and each of the arm portions 204 when the soft tissue anchor system 200 is implanted in the soft body tissue 12. The fabric body 201 comprises narrow waist portions 203 located, and extending, between the base portion 202 and each arm portion 204. The narrow waist portions 203 are thinner than the arm portions 204 and the base portion 202, and are arranged to improve the seating and prevent movement of the fabric body 201 when implanted in soft body tissue 12 prior to collapsing the fabric body. The narrow waist portions 203 provide grooves or channels in which the soft body tissue 12 will favourably sit, upon implantation of the soft body tissue anchor 200 in soft body tissue 12. The soft tissue anchor system 200 also comprises a tensile line 214’ threaded through holes 207 located long the arm portions 204 and the base portion 202. The tensile line 214’ is free to pass through the threaded holes 207, but is otherwise fixed at, or to, the ends of the arm portions 204. Upon application of a tensile force pulling the line 214’, the line 214’ collapses the arm portions 204 in folds towards the base portion 202, to sandwich soft body tissue 12 between the base portion 202 and each of the arm portions 204. The tensile line 214’ is joined to an artificial line 214, which may be an artificial chordae line, at a point 215. End caps 208 are located at the ends of each arm portion 204, and fixed to the ends of the arm portions 204 and respective ends of the tensile line 214’. The end caps 208 have a construction as described in relation to figure 1K above, but in other embodiments can instead be alternatively formed of a single part construction. The soft tissue anchor system 200 shown in figure 2 is in a rest configuration. In the rest configuration, the fabric body 201 is not subjected to any constraining forces. Thus, in the rest configuration the fabric body 201 is at rest - it is relaxed, or unconstrained. In the rest configuration the two arm portions 204 extend from the base portion 202 in substantially different respective directions to one another. In the rest configuration for the present fabric body 201, the fabric body 201 also lies substantially flat. Figure 3 shows the soft tissue anchor system 200 of figure 2 in an implantable configuration. The implantable configuration suitable for implanting the fabric body 201 into soft body tissue 12. In the implantable configuration the fabric body 201 can be ready to engage with soft body tissue 12. This can be, for example, due to the arm portions 204 being in a position extending substantially perpendicular to the surface of the soft body tissue with which they are to engage. In the implantable configuration the arm portions 204 extend from the base portion 202 in substantially the same direction. This can be achieved by the arm portions 204 bending or folding about the base portion 102. In other embodiments, the fabric body 201 can be in the implantable configuration via the base portion 202 folding or bending. It is also contemplated that, in some embodiments, the arm portions 204 will extend from the base portion 202 in substantially the same direction and be parallel with one another. In other embodiments, the arm portions 204 will extend from the base portion 202 in substantially the same direction but can be partially splayed relative to one another. As can be seen in figure 2, the arm portions 204 of the present embodiment extend in substantially opposite respective directions from the base portion 202 when in the rest configuration. As such, the fabric body 201 has an elongate or straight form at rest, i.e. the arm portions 204 are collinear in the rest configuration. Further, the arm portions 204 are collinear with the base portion 202. By having the fabric body 201 take on a shape at rest in which the arm portions 204 extend in substantially opposite directions, the fabric body 201 has fewer sharp changes in direction or bends in its shape. In figure 2 in particular, a long axis of each arm portion 204 and a long axis of the base portion 202 (in this case the width of the base portion 202), are collinear with one another. Accordingly, fibres in the fabric material forming the fabric body 201 can extend continuously for a greater proportion of the overall length of the fabric body 201 compared to the U-shaped fabric body 101 shown in figure 1H. Since continuous fibres forming the fabric material extend for a greater length rather than being cut, the strength of the fabric material (e.g. the tensile strength) forming the fabric body 201 can be improved. Further, since the fabric body 201 is naturally pliable, the fabric body 201 can still be moved into the deployable configuration as illustrated in figure 3 - there is no notable loss of functionality for the soft tissue anchor system 200. In the present embodiment, the fabric body 201 can be moved from the rest configuration and into the implantable configuration by bending, e.g. by folding, the arm portions 204 about the base portion 202. As described above in relation to figure 1L, the fabric body 201 is also movable from a deployable, or stowed, configuration into the rest configuration via action of the wire guide members 118 during implantation of the soft tissue anchor system 200. Figures 4A-C show the soft tissue anchor system 200 during implantation in soft body tissue 12. The procedure to implant the soft tissue anchor system 200 is similar to that used to implant the soft tissue anchor system 100 described above. As shown in figure 4A, the soft tissue anchor system 200 is implanted in the soft body tissue 200 by pushing the arm portions 204 through the soft tissue 12 using wire guide members (not shown). The soft body tissue 12 is a heart valve leaflet, and the arm portions 204 are implanted into the atrial surface 12a of the leaflet 12. The fabric body 201 is in the implantable configuration, during this step of the implantation process. As shown in figures 4B and 4C, once the wire guide members are withdrawn, tension is applied to the line 214, 214’ such that the arm portions 204 collapse in folds towards the base portion 202. The soft body tissue 12 is sandwiched therebetween, and the line 214, 214’ descends over an edge 12c of the leaflet 12. Under tension of the line 214, 214’ the end caps 208 lie parallel to a plane of the folds of the arm portions 204, and parallel to a plane of the surface 12b of the leaflet 12. The fabric body 201 is in the deployed, or implanted, configuration. Figure 5 shows an alternative form for the fabric body 301 of a soft tissue anchor system. The fabric body 301 can be used in place of the fabric body 201 described above in relation to figures 2-4C. The fabric body 301 comprises a base portion 302 and two arm portions 304 extending from the base portion 302. In a rest configuration, as shown in figure 5, the two arm portions 304 extend from the base portion 302 in opposite respective directions. The ends of the arm portions 304 can be fixed to respective end caps. The fabric body 301 also includes holes 307 for a line to pass through. The fabric body 301 includes bulging portions 303 located, and extending, between the base portion 302 and each arm portion 304. Akin to the narrow waist portions 203 described above, the bulging portions 303 provide a change in cross-section which, during implantation of the fabric body 301 in soft body tissue, can aid with improving the stability of the fabric body 301 when implanted in the soft body tissue. The bulging portions 303 are wider than the arm portions 304 and the base portion 302 in the illustrated embodiment. In one mode of use, the bulging portions 303 are pushed through the soft body tissue 12 during implantation. Since the bulging portions 303 are wider than the arm portions 304, they act to prevent the arm portions 304 of the fabric body 301 from being pulled out of the soft body tissue 12 when implanted. In another mode of use, the bulging portions 303 are wider than the arm portions 304 and the base portion 302, so as to prevent the fabric body 301 from being implanted too deeply into the soft body tissue. In this way, the bulging portions 303 can aid with locating the arm portions 301 at the correct depth in the soft body tissue. Whilst embodiments show fabric bodies 201, 301 comprising one of narrow waist portions 203 or bulging portions, in other embodiments fabric bodies may include both narrow waist portions and bulging portions located, or extending, between each arm portion and the base portion. Figure 6 shows a tubular fabric body 401 of a soft tissue anchor system. The tubular fabric body 401 can be used in place of the fabric body 201 described above in relation to figures 2-4C. The tubular fabric body 401 comprises a base portion 402 and two arm portions 404 extending from the base portion 402. In a rest configuration, as shown in figure 6, the two arm portions 404 extend from the base portion 402 in opposite respective directions. The ends of the arm portions 404 can be fixed to respective end caps. The fabric body 401 also includes holes 407 for a line to pass through. Forming the fabric body 401 from a tubular fabric material may improve the strength of the fabric body 401, since the fibres forming the fabric material can run continuously, or for at least a greater proportion uncut or uninterrupted, both along a length of the fabric body 401 and around a circumference of the fabric body 401. The tubular fabric body 401 can also be formed to have narrow waist portions and / or bulging portions located, or extending, between the base portion 402 and the arm portions 404. To form a narrow waist portion, the tubular fabric body 401 is constricted such as by tightening a loop of fibre around the circumference of the fabric body 401. To form a bulging portion, the fabric body 401 can be compressed in the axial direction to cause the fabric body 401 to bulge outwards; it can then be fixed to maintain the bulging portion. In other embodiments, narrow waist portions and / or bulging portions are formed during manufacture of the fabric body 401 by controlling the winding rate and winding angle of the fabric material. Figure 7 shows an alternative fabric body 501 of a soft tissue anchor system. The fabric body 501 can be used in place of the fabric body 201 described above in relation to figures 3-4C. The fabric body 501 comprises a base portion 502 and two arm portions 504 extending from the base portion 502. The fabric body 501 comprises narrow waist portions 503 located between the base portion 502 and each arm portion 504. The ends of the arm portions 504 can be fixed to respective end caps. The fabric body 501 also includes holes 507 along its length for threading a line. The fabric body 501 is shown in a rest configuration. In the rest configuration, the arm portions 504 extend from the base portion 502 in different respective directions. In this particular embodiment, one arm portion 504 extends in a direction perpendicular to the direction of the other arm portion 504. One of the arm portions 504 has a sharp change in direction or bend in its shape from the base portion 502. However, since there is no change in direction or bend in shape from the base portion 502 from the other arm portion 50, the fibres in the in the fabric material forming the fabric body 501 can still extend continuously for a greater proportion of the fabric body 501 compare to the U-shaped fabric body 101 shown in figure 1H. Accordingly, the strength of the fabric material forming the fabric body 501 may still be improved. Further, 5 since the fabric body 501 is naturally pliable, the fabric body 501 can still be moved into the deployable configuration for implantation in soft body tissue.

Claims

1. A soft tissue anchor system for implantation in soft body tissue to hold an artificial line, the anchor comprising:a fabric body comprising a base portion and two arm portions extending from the base portion;wherein each arm portion is arranged to collapse towards the base portion such that, in use, the body tissue is sandwiched between the base portion and each of the arm portions;wherein the fabric body is movable between a rest configuration and an implantable configuration; andwherein, in the rest configuration, the two arm portions extend from the base portion in different respective directions.

2. A soft tissue anchor system as claimed in claim 1, wherein at least one arm portion and the base portion are collinear in the rest configuration.

3. A soft tissue anchor system as claimed in claim 1 or 2, wherein the two arm portions and the base portion are collinear in the rest configuration.

4. A soft tissue anchor system as claimed in claim 1,2 or 3, wherein the fabric body comprises only the two arm portions and has an elongate form in the rest configuration.

5. A soft tissue anchor system as claimed in any preceding claim, wherein the fabric body is a tubular fabric body.

6. A soft tissue anchor system as claimed in any preceding claim, comprising: a tension line threaded through the arm portions and the base portion;wherein the tension line is configured to collapse each arm portion in folds towards the base portion when a tensile force is applied to the tension line.

7. A soft tissue anchor system as claimed in claim 6, wherein the tension line is fixed to each arm portion at an end of each arm portion distal to the base portion.

8. A soft tissue anchor system as claimed in claim 6 or 7, wherein the tension line comprises a plurality of bridle lines, wherein each bridle line is associated with a respective arm portion; andwherein each bridle line is connected to a common bridle point, wherein the bridle point is configured to place each bridle line under tension when a tensile force is applied to the bridle point.

9. A soft tissue anchor system as claimed in claim 6, 7 or 8, comprising:the artificial line;wherein the artificial line is configured to apply the tensile force.

10. A soft tissue anchor system as claimed in any preceding claim, wherein each arm portion comprises an end cap fixed at an end of each arm portion distal to the base portion;wherein each end cap comprises an opening configured to engage a wire guide member for implanting the fabric body in the body tissue.

11. A soft tissue anchor system as claimed in claim 10, wherein each end cap comprises an outer tubular member and an inner tubular member, wherein the outer tubular member is configured to receive the inner tubular member; andwherein the inner tubular member defines the opening configured to engage the wire guide member.

12. A soft tissue anchor system as claimed in any preceding claim, wherein the base portion defines a maximum width of the fabric body in the deployable configuration.

13. A soft tissue anchor system as claimed in any preceding claim, wherein the fabric body comprises a narrow waist portion extending between the base portion and at least one of the arm portions.

14. A soft tissue anchor system as claimed in any preceding claim, wherein the fabric body comprises a bulged portion extending between the base portion and at least one of the arm portions.

15. A soft tissue anchor system as claimed in any preceding claim, wherein the soft tissue anchor system is a leaflet anchor system for implantation in a heart valve leaflet to hold an artificial chordae line.

16. A catheter device for implanting a soft tissue anchor system in heart tissue, the catheter device comprising:a housing section, wherein the housing section extends from a distal end of the catheter device along the length of the catheter device toward a proximal end of the catheter device; anda soft tissue anchor system as claimed in any preceding claim located within the housing section.

17. A catheter device as claimed in claim 16, comprising:a leaflet anchor for placement in a leaflet of a heart valve, wherein the leaflet anchor is the soft tissue anchor system, wherein the leaflet anchor is arranged to be coupled to the artificial line; anda leaflet anchor deployment mechanism for deploying the leaflet anchor to attach it to the leaflet of the heart.

18. A catheter device as claimed in claim 17, comprising:a mechanical gripper device for grasping the leaflet of the heart valve; anda leaflet anchor tube for housing the leaflet anchor before deployment into the body tissue;wherein the gripper device and the leaflet anchor are arranged such that when, in use, the gripper device grasps the leaflet, the leaflet anchor system can be pushed out of the leaflet anchor tube to pierce the leaflet and deploy the anchor such that it is implanted in the leaflet.

19. A catheter device as claimed in claim 17 or 18, comprising:a papillary anchor arranged to be coupled to the artificial line at a distance from the leaflet anchor; anda papillary anchor deployment mechanism for deploying the papillary anchor to attach it to papillary muscle of the heart.

20. A method of manufacturing a soft tissue anchor system as claimed in any one of claims 1 to 15, the method comprising:fabricating the fabric body; andconfiguring each arm portion to collapse.

21. A method as claimed in claim 20, wherein the step of fabricating the fabric body comprises laser cutting a fabric.

22. A method of implanting a soft tissue anchor system as claimed in any one of claims 1 to 15 in soft body tissue, the method comprising:moving the fabric body into the implantable configuration;pushing each arm portion through the body tissue; and5 collapsing each arm portion towards the base portion such that the body tissue issandwiched between the base portion and each of the arm portions.

23. A method as claimed in claim 22, comprising:engaging each arm portion using a respective wire guide member;10 wherein the step of pushing each arm portion through the body tissue is performedusing the respective wire guide member.

24. A method as claimed in claim 23, wherein the respective wire guide members are used to move the fabric body into the implantable configuration.

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