Patent Publication Number: US-11382753-B2

Title: Devices and methods for positioning and monitoring tether load for prosthetic mitral valve

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. patent application Ser. No. 15/251,269, filed on Aug. 30, 2016, which is a continuation of International Application No. PCT/US2015/019418, filed Mar. 9, 2015, which claims priority to and the benefit of U.S. Provisional Patent Application No. 61/950,429, filed Mar. 10, 2014, entitled “Devices and Methods for Monitoring Tether Load for Prosthetic Mitral Valve,” U.S. Provisional Patent Application No. 61/970,887, filed Mar. 26, 2014, entitled “Post-Deployment Adjustment of a Prosthetic Mitral Valve,” and U.S. Provisional Patent Application No. 61/970,882, filed Mar. 26, 2014, entitled “Post-Deployment Adjustment of a Prosthetic Mitral Valve.” The disclosure of each of the foregoing applications is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     Embodiments are described herein that relate to devices and methods for anchoring a medical device such as a prosthetic heart valve replacement, and more particularly to devices and methods for the post-deployment adjustment and/or re-positioning of such a medical device. 
     Some known prosthetic heart valves, such as prosthetic mitral valves, include one or more tethers that extend from the valve to the exterior of the heart, and are secured to an outer ventricular wall of the heart with an epicardial anchor device. During such procedures, positioning the anchor device and providing a desired tension to the securing tether can be challenging. Many known devices do not have the ability to make adjustments to the anchor device or to the tension of the tether after initial placement. Further, known devices do not have the ability to measure and monitor the tension on the tether during deployment of the valve to assist in providing an optimal tension and position. 
     Some problems associated with improper tensioning of a securing tether can include, for example, the tether becoming progressively slack over time, a tether which has been overtightened and is deforming the positioning of the deployed valve, and a tether which has been deployed in a less than optimal angular configuration or has migrated such that the valve axis is no longer orthogonal to the plane of the native valve&#39;s annulus. 
     Accordingly, there is a need for devices and methods for adjusting and/or repositioning a prosthetic heart valve after its initial deployment and for monitoring the tension on a securing tether extending from the prosthetic heart valve. 
     SUMMARY 
     Apparatus and methods are described herein for positioning an epicardial anchor device and measuring the load of a tether extending from a prosthetic heart valve and coupled to the epicardial anchor device. In some embodiments, an apparatus includes a handle assembly coupled to an elongate member and a docking member coupled to a distal end of the elongate member. The docking member can be releasably coupled to an epicardial anchor device configured to secure a tether extending from a prosthetic heart valve implanted with a heart at a location on an exterior of a ventricular wall of the heart. A force sensor device is coupled to the handle assembly and can measure a force exerted on the force sensor device. The force is associated with a tension of the tether extending through the elongate member, handle assembly and force sensor device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic cross-sectional illustration of portion of a heart with a prosthetic mitral valve implanted therein and an epicardial anchor device anchoring the mitral valve in position. 
         FIG. 2  is a schematic illustration of an epicardial anchor device, according to an embodiment. 
         FIG. 3  is a schematic illustration of a positioning device, according to an embodiment. 
         FIG. 4  is a top perspective view of an epicardial anchor device, according to another embodiment. 
         FIG. 5  is a top view of the epicardial anchor device of  FIG. 4 . 
         FIG. 6  is an exploded view of the epicardial anchor device of  FIG. 4 . 
         FIG. 7  is a cross-sectional perspective view of the epicardial anchor device of  FIG. 4  with a locking pin of the device shown in a first position. 
         FIG. 8  is a cross-sectional side view of the epicardial anchor device of  FIG. 4  with the locking pin of the device shown in the first position. 
         FIG. 9  is a cross-sectional bottom perspective view of the epicardial anchor device of  FIG. 4  with the locking pin shown in a second position. 
         FIGS. 10 and 11  are a top perspective and a bottom perspective view, respectively, of a hub member of the epicardial anchor device of  FIG. 4 . 
         FIG. 12  is an enlarged top view of a portion of the epicardial anchor device of  FIG. 4 . 
         FIG. 13  is a perspective view of a positioning device, according to an embodiment. 
         FIG. 14  is a top view of a portion of the positioning device of  FIG. 13 . 
         FIG. 15  is a cross-sectional view of the portion of the positioning device of  FIG. 14 . 
         FIG. 16A  is a perspective view and  FIG. 16B  is a top view of a portion of the positioning device of  FIG. 13 . 
         FIG. 17A  is a perspective view of a portion of the positioning device of  FIG. 13  shown partially exploded. 
         FIG. 17B  is a perspective view of the portion of the positioning device of  FIG. 17A . 
         FIG. 18  is a top view of a positioning device, according to another embodiment. 
         FIG. 19  is a perspective view of a portion of the positioning device of  FIG. 18  shown partially exploded. 
         FIG. 20  is a perspective view of the portion of the positioning device of  FIG. 19 . 
         FIG. 21  is a schematic illustration of a portion of the positioning device of  FIG. 18 . 
         FIG. 22  is a perspective view of a positioning device, according to another embodiment, shown coupled to an epicardial anchor device. 
         FIG. 23  is a top view of the positioning device of  FIG. 22 . 
         FIG. 24  is a cross-sectional view of a portion of the positioning device of  FIG. 22 , taken along line  24 - 24  in  FIG. 23 . 
         FIG. 25  is a perspective view of a portion of the positioning device of  FIG. 22 . 
         FIG. 26  is a perspective view of a force sensor device of the positioning device of  FIG. 22 . 
         FIG. 27  is an exploded perspective view of the force sensor device of  FIG. 26 . 
         FIG. 28  is a perspective view of a portion of the force sensor device of  FIG. 26 . 
         FIG. 29  is a perspective view of a portion of the positioning device of  FIG. 22 . 
         FIG. 30  is a side view of the positioning device of  FIG. 22 . 
         FIG. 31  is a partial cross-sectional side view of a tension limiting device according to an embodiment. 
         FIG. 32  is a top view of a tether release tool, according to an embodiment. 
         FIG. 33  is a perspective view of an end portion of the tether release tool of  FIG. 32 . 
         FIG. 34  is a perspective view of a portion of the tether release tool of  FIG. 32  shown being coupled to an epicardial anchor device. 
         FIG. 35  is a perspective view of a portion of the tether release tool of  FIG. 32  shown coupled to the epicardial anchor device of  FIG. 34 . 
         FIG. 36  is a perspective view of a force sensor device according to an embodiment. 
         FIG. 37  is an exploded perspective view of the force sensor device of  FIG. 36 . 
         FIG. 38  is a cross-sectional perspective view of the force sensor device of  FIG. 36 . 
         FIG. 39  is a side view of a portion of a tether with a marker band according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Apparatus and methods are described herein that can be used for the post-deployment adjustment and/or re-positioning of a transcatheter prosthetic heart valve, such as a mitral valve, that has been deployed into the annulus of a native valve, such as a mitral valve. For example, such a prosthetic mitral valve can be anatomically secured in a two-phase process that includes securing the prosthetic mitral valve in the native annulus using an atrial cuff and a tether axial tensioning system in combination with a laterally expanded stent, and to methods for making such systems. 
     In some embodiments, apparatus and methods are described herein for monitoring the tension applied to a securing tether extending from a prosthetic mitral valve that has been deployed into the native mitral valve. 
     Various embodiments described herein address problems concerning valve delivery and deployment, valve compliance, perivalvular leaking, hemodynamic issues such as left ventricular outflow tract (LVOT) interference, clotting, cardiac remodeling, etc. 
     In some embodiments, an adjustable tether and epicardial anchor device for a compressible prosthetic heart valve replacement are described herein, which can be deployed into a closed beating heart using, for example, a transcatheter delivery system. In some embodiments, such a valve replacement device can be deployed in a minimally invasive fashion and by way of example considers a minimally invasive surgical procedure utilizing the intercostal or sub-xyphoid space for valve introduction. To accomplish this, the valve is formed so that it can be compressed to fit within a delivery system and then ejected from the delivery system into the target location, for example, the annulus of the mitral or tricuspid valve. 
     In some embodiments, there is provided a method of adjusting the length and/or tension of a tether for a tethered transcatheter prosthetic heart valve after a transcatheter valve implantation procedure in a patient. Such a method can include adjusting the transluminal length of a ventricular tether, wherein the tether is anchored between an epicardial anchor device that is releasably affixed to an external epicardial surface of the heart and a valve-based fastening system on a transcatheter prosthetic heart valve that is deployed in the native valve annulus of the patient. Upon releasing the tether from the epicardial anchor device, the tether length and/or tension is adjusted and the tether is re-fastened to the epicardial anchor device. 
     In another embodiment, there is provided a method as above, further including capturing the tether, threading the tether through a tether release tool, re-engaging the tether release tool with the epicardial anchor device, unlocking the pin and releasing the tether. In some embodiments, after adjusting the length of the tether (longer or shorter), the tether tensioning force can be measure again, and then the tether can be re-pinned into the epicardial anchor device. 
     In some embodiments, there is provided a device for adjusting the length and/or tension of a tether for a tethered transcatheter prosthetic heart valve after a transcatheter valve implantation procedure in a patient. The device can include a positioning device for operatively engaging an epicardial anchor device, and the positioning device includes a positioning rod. The positioning rod member includes at a distal end of an elongate member a docking member that has a hinged frame that is connected to a circular platform having two bent locking tines or flanges located across from each other. The elongate member may or may not be hollow and includes a mechanism associated therewith for inserting or withdrawing a locking pin from a tether. The positioning device further includes a pin locking thumb wheel sub-component to actuate the pin locking mechanism that drives or removes a piercing pin on the epicardial anchor device into or from the tether. The positioning device further includes a transparent segment between the pin locking thumb wheel and a proximal end of the positioning device. The transparent segment has an implant position scale marked thereon. A proximal end of the positioning device also has a tether attachment pin vise. When the tether is threaded through the epicardial anchor device and the positioning device, and when the tether is drawn/pulled to the desired tension, e.g., such that the deployed valve seats firmly in the native annulus and any regurgitation seen on fluoroscopy or echocardiography is no longer present, the tether tensioning can be adjusted by visually observing the tether within the transparent segment of the positioning device and comparing the longitudinal distance travelled against an implant position scale. After the tether is suitably located, the pin locking thumb wheel is actuated and the pin locks the tether in place on the epicardial anchor device. The docking member is then disengaged from the epicardial anchor device. 
     In some embodiments, there is provided a tether release tool that has a distal tip that includes a shaped anchor device-engagement tip, a distal opening and a passageway in fluid communication with an angled tether capture/recapture access port. The angled tether capture/recapture access port allows a tether to be captured and released from a locked position, and the shaped anchor device-engagement tip is configured to fit within a similarly shaped portion of an epicardial anchor device. 
     In some embodiments, there is provided a method of tethering a prosthetic heart valve during a transcatheter valve replacement procedure that includes deploying a transcatheter prosthetic heart valve in a patient using as an anchor an adjustable tether that is anchored within the heart between an apically affixed epicardial anchor device and a stent-based fastening system (e.g., attached to the prosthetic heart valve). The transcatheter prosthetic heart valve includes an expandable tubular stent having a cuff and an expandable internal leaflet assembly. The cuff includes wire covered with stabilized tissue or synthetic material, and the leaflet assembly is disposed within the stent and includes stabilized tissue or synthetic material. 
     In some embodiments, an epicardial anchor device for anchoring a transluminal (transventricular) suture/tether includes a substantially rigid suturing disk having a tether-capture mechanism such as an axial tunnel, a winding channel, or a functional equivalent, and a tether locking mechanism such as a locking pin or screw that intersects the axial tunnel, a locking pin or screw operatively associated with the winding channel, a cam device like a rope lock that grips the tether by compression between two cams or a cam and fixed locking wall, a metal compression fastener, a tooth and pawl device, various combinations of the above, or a functional equivalent thereof. 
     In another embodiment, an epicardial anchor device for anchoring a transluminal suture includes a substantially rigid suturing disk having an axial tunnel, a locking pin locking pin tunnel that intersects the axial tunnel, a locking pin operatively associated with the locking pin tunnel, one or more radial channels that do not intersect with the axial tunnel and that do not intersect the locking pin tunnel, and a winding channel circumferentially disposed within a perimeter sidewall of the disk. 
     In some embodiments, an epicardial anchor device further includes a polyester velour coating. In some embodiments, the one or more radial channels include four radial channels. In some embodiments, the one or more radial channels each have an enlarged axial keyhole tunnel. 
     In some embodiments, an epicardial anchor device includes a flexible pad operatively associated with the rigid tethering/suturing disk, and the flexible pad has a through-hole longitudinally aligned with the axial tunnel. In some embodiments, the epicardial anchor device further includes a sleeve gasket operatively associated with the rigid tethering/suturing disk, and the sleeve gasket has a lumen longitudinally aligned with the axial tunnel. In some embodiments, the device further includes a sleeve gasket attached to the rigid tethering/suturing disk and a flexible pad attached to the sleeve gasket. In such an embodiment, the sleeve gasket has a lumen longitudinally aligned with the axial tunnel of the tethering/suturing disk, and the flexible pad has a through-hole longitudinally aligned with both the lumen of the sleeve gasket and the axial tunnel of the tethering/suturing disk. 
     In some embodiments, a device for anchoring a transluminal tethering/suture includes a substantially rigid tethering/suturing disk, a sleeve gasket connected to the tethering/suturing disk, and a flexible pad connected to the sleeve gasket. The substantially rigid tethering/suturing disk has an axial tunnel, a locking pin tunnel that intersects the axial tunnel, a locking pin operatively associated with the locking pin tunnel, one or more radial channels that do not intersect with the axial tunnel and that do not intersect the locking pin tunnel, and a winding channel circumferentially disposed within a perimeter sidewall of the disk. The sleeve gasket is in longitudinal alignment with the axial tunnel, and the flexible pad has a through-hole longitudinally aligned with both the lumen of the sleeve gasket and the axial tunnel of the tethering/suturing disk. 
     In another embodiment, an epicardial anchor device for anchoring a transluminal suture includes a substantially rigid tethering/suturing disk having an axial tunnel, a locking pin tunnel that intersects the axial tunnel, and a locking pin operatively associated with the locking pin tunnel. 
     In some embodiments, a method for anchoring a transluminal suture includes affixing a transluminal suture to an epicardial anchor device as described herein, and positioning the epicardial anchor device external to a body lumen. The transluminal tether/suture extends from within the lumen to the epicardial anchor device. 
     In another embodiment, a tether and epicardial anchor device as described herein further includes a tether tension load measuring device operatively associated with the tether. In some embodiments, a tension sensor includes one or more electronic strain gage transducers. The tension sensor can be configured for dynamic tension, static tension, or both dynamic and static tension measurement. In some embodiments, the tether is loaded with a specific tension, such as, for example, 1.0 to 4.0 lbs. 
     In another embodiment, there is provided a device and exemplary method for monitoring and/or controlling tether load during implant positioning using a fluid chamber device described in more detail below. A force sensor device having an annular fluid chamber is installed on the proximal end of a positioning device. This chamber is connected to a pressure transducer and then connected to a monitoring display. In some embodiments, a mechanical indicator can be used in conjunction therewith. A spring device may be connected to a mechanical tension meter to show load range. In some embodiments, the force sensor device remains as an integral part of the epicardial fastening pad assembly and is not removed after the tether tensioning is performed. 
     In some embodiments, a sterile surgical kit can be provided. The sterile surgical kit can contain a transcatheter delivery system, an epicardial anchor device and/or a transcatheter prosthetic valve. 
     In another embodiment, there is provided method of treating mitral or tricuspid regurgitation in a patient, which includes surgically deploying an adjustable-tethered prosthetic heart valve into the mitral or tricuspid annulus of the patient. 
     In another embodiment, the space between the cuff tissue and cuff Dacron liner (inside-outside) may be used to create a cuff that is expandable, swellable or may be inflated, and which provides an enhanced level of sealing of the cuff against the annular tissue. 
     Various embodiments described herein address problems concerning valve delivery and deployment, valve compliance, perivalvular leaking, hemodynamic issues such as LVOT interference, clotting, cardiac remodeling and so forth. 
     In some embodiments described herein, a tethering system for a prosthetic mitral valve is provided that is designed to maintain integrity to about 800 million cycles, or about 20 years. The use of a compressible prosthetic valve delivered via transcatheter endoscope techniques addresses various delivery issues. Deployment is addressed through the use of a prosthetic valve having a shape that features a tubular stent body that contains leaflets and an atrial cuff. This allows the valve to seat within the mitral annulus and be held by the native mitral leaflets. The use of a flexible valve attached using an apical tether provides compliance with the motion and geometry of the heart. The geometry and motion of the heart are well-known as exhibiting a complicated biphasic left ventricular deformation with muscle thickening and a sequential twisting motion. The additional use of the apically secured ventricular tether helps maintain the prosthetic valve&#39;s annular position without allowing the valve to migrate, while providing enough tension between the cuff valve annulus to reduce and eliminate perivalvular leakage. The use of an adjustable tether or an adjustable paired-tether that is attached to an apical location can reduce or eliminate the cardiac muscle remodeling that has been witnessed in prior art devices. Some prior art devices can have a problem with unwanted change in tissue at the anchoring locations, as well as heart-generated migration of the original anchoring locations to new locations that reduce or destroy the prior art valve&#39;s effectiveness. The use of a compliant valve prosthesis and the special shape and features help reduce or eliminate clotting and hemodynamic issues, including LVOT interference problems. Many prior art valves were not designed with an awareness of, or were not able to address, problems with blood flow and aorta/aortic valve compression issues. 
     Structurally, a prosthetic heart valve as used with the apparatus and methods described herein can include a self-expanding tubular body having a cuff at one end and one or more tethers attached at the other end. Disposed within the tubular body is a leaflet assembly that contains the valve leaflets, and the valve leaflets can be formed from stabilized tissue or other suitable biological or synthetic material. In one embodiment, the leaflet assembly may include a wire form where a formed wire structure is used in conjunction with stabilized tissue to create a leaflet support structure which can have anywhere from 1, 2, 3 or 4 leaflets, or valve cusps disposed therein. In another embodiment, the leaflet assembly is wireless and uses only the stabilized tissue and stent body to provide the leaflet support structure, without using wire, and which can also have anywhere from 1, 2, 3 or 4 leaflets, or valve cusps disposed therein. 
     The upper cuff portion may be formed by heat-forming a portion of a tubular Nitinol® braided (or similar) stent such that the lower portion retains the tubular shape, but the upper portion is opened out of the tubular shape and expanded to create a widened collar structure that may be shaped in a variety of functional regular or irregular funnel-like or collar-like shapes. In one embodiment, the entire structure is formed from a laser-cut stent and collar design, as described further herein 
     As used in this specification, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, the term “a member” is intended to mean a single member or a combination of members, “a material” is intended to mean one or more materials, or a combination thereof. 
     As used herein, the words “proximal” and “distal” refer to a direction closer to and away from, respectively, an operator of, for example, a medical device. Thus, for example, the end of the medical device closest to the patient&#39;s body (e.g., contacting the patient&#39;s body or disposed within the patient&#39;s body) would be the distal end of the medical device, while the end opposite the distal end and closest to, for example, the user (or hand of the user) of the medical device, would be the proximal end of the medical device. 
     A prosthetic mitral valve can be anchored to the heart at a location external to the heart via one or more tethers coupled to an anchor device, as described herein. For example, the tether(s) can be coupled to the prosthetic mitral valve and extend out of the heart and be secured at an exterior location (e.g., the epicardial surface) with an anchor device, as described herein. An anchor device as described herein can be used with one or more such tethers in other surgical situations where such a tether may be desired to extend from an intraluminal cavity to an external anchoring site. Various different types and/or configurations of an anchor device (also referred to herein as “epicardial anchor device” or “epicardial pad” or “pad”) can be used to anchor a prosthetic mitral valve in the methods described herein. For example, any of the epicardial anchor devices described in PCT International Application No. PCT/US2014/049218, filed Jul. 31, 2014, entitled “Epicardial Anchor Devices and Methods,” (referred to herein as “the &#39;218 PCT application”), the disclosure of which is incorporated herein by reference in its entirety, can be used. 
       FIG. 1  is a schematic cross-sectional illustration of the left ventricle LV and left atrium LA of a heart H having a transcatheter prosthetic mitral valve PMV deployed therein and an epicardial anchor device EAD as described herein securing the prosthetic mitral valve PMV in place.  FIG. 1  illustrates the prosthetic mitral valve PMV seated into the native valve annulus and held there using an atrial cuff AC of the prosthetic mitral valve PMV and a ventricular tether T secured with attachment portions Tp to the prosthetic mitral valve PMV and to the epicardial anchor EAD. The epicardial anchor device EAD can be various different shapes, sizes, types and configurations, for example, the EAD can be an epicardial anchor device such as those described in the &#39;218 PCT application incorporated by reference above. Further, the prosthetic mitral valve PMV and the tether T can be, for example, a prosthetic mitral valve and tether, respectively, as described in the &#39;218 PCT application or other suitable types and configurations. 
       FIG. 2  is a schematic illustration of an epicardial anchor device  100  (also referred to herein as “anchor device” or “epicardial anchor”) according to an embodiment. The anchor device  100  can be used to anchor or secure a prosthetic mitral valve PMV deployed between the left atrium LA and left ventricle LV of a heart H. The anchor device  100  can be used, for example, to anchor or secure the prosthetic mitral valve PMV via a suturing tether  128  as described above with respect to  FIG. 1 . The anchor device  100  can also seal a puncture formed in the ventricular wall (not shown in  FIG. 2 ) of the heart during implantation of the prosthetic mitral valve PMV. The anchor device  100  can also be used in other applications to anchor a medical device (such as any prosthetic atrioventricular valve or other heart valve) and/or to seal an opening such as a puncture. 
     The anchor device  100  can include a pad (or pad assembly)  120 , a tether attachment member  124  and a locking pin or locking pin assembly  126 . The pad  120  can contact the epicardial surface of the heart and can be constructed of any suitable biocompatible surgical material. The pad  120  can be used to assist the sealing of a surgical puncture formed when implanting a prosthetic mitral valve. 
     In some embodiments, the pad  120  can be made with a double velour material to promote ingrowth of the pad  120  into the puncture site area. For example, pad or felt pledgets can be made of a felted polyester and may be cut to any suitable size or shape, such as those available from Bard® as PTFE Felt Pledgets having a nominal thickness of 2.87 mm. In some embodiments, the pad  120  can be larger in diameter than the tether attachment member  124 . The pad  120  can have a circular or disk shape, or other suitable shapes. 
     The tether attachment member  124  can provide the anchoring and mounting platform to which one or more tethers  128  can be coupled (e.g., tied or pinned). The tether attachment member  124  can include a base member (not shown) that defines at least a portion of a tether passageway (not shown) through which the tether  128  can be received and pass through the tether attachment member  124 , and a locking pin channel (not shown) through which the locking pin  126  can be received. The locking pin channel can be in fluid communication with the tether passageway such that when the locking pin  126  is disposed in the locking pin channel, the locking pin  126  can contact or pierce the tether  128  as it passes through the tether passageway as described in more detail below with reference to specific embodiments. 
     The locking pin assembly  126  can be used to hold the tether  128  in place after the anchor device  100  has been tightened against the ventricular wall and the tether  128  has been pulled to a desired tension. For example, the tether  128  can extend through a hole in the pad  120 , and through the tether passageway of the tether attachment member  124 . The locking pin  126  can be inserted or moved within the locking pin channel  134  such that it pierces or otherwise engages the tether  128  as the tether  128  extends through the tether passageway of the tether attachment member  124 . Thus, the locking pin  126  can intersect the tether  128  and secure the tether  128  to the tether attachment member  124 . 
     The tether attachment member  124  can be formed with, a variety of suitable biocompatible material. For example, in some embodiments, the tether attachment member  124  can be made of polyethylene, or other hard or semi-hard polymer, and can be covered with a polyester velour to promote ingrowth. In other embodiments, the tether attachment member  124  can be made of metal, such as, for example, Nitinol®, or ceramic materials. The tether attachment member  124  can be various sizes and/or shapes. For example, the tether attachment member  124  can be substantially disk shaped. 
     In use, after a PMV has been placed within a heart, the tether extending from the PMV can be inserted into the tether passageway of the anchor device  100  and the tension on the tether attachment device can be adjusted to a desired tension. Alternatively, in some cases, the tether extending from the PMV can be coupled to the anchor device  100  prior to the PMV being placed within the heart. The anchor device  100  (e.g., some portion of the anchor device such as the tether attachment member  124 , or the lever arm or hub depending on the particular embodiment) can be actuated such that the locking pin  126  intersects the tether passageway and engages a portion of the tether disposed within the tether passageway, securing the tether to the tether attachment member. In some embodiments, prior to inserting the tether into the tether passageway, the anchor device  100  can be actuated to configure the anchor device  100  to receive the tether. For example, if the tether attachment member includes a lever arm movably coupled to the base member, the lever arm may need to be moved to an open position to allow the tether to be inserted. In some embodiments, the anchor device  100  can be actuated by rotating a hub relative to a base member of the tether attachment member  124  such that the locking pin  126  is moved from a first position in which the locking pin is spaced from the tether passageway and a second position in which the locking pin intersects the tether passageway and engages or pierces the portion of the tether. 
       FIG. 3  is a schematic illustration of an embodiment of a positioning device  142  that can be used to position the epicardial anchor device  100  and measure the tension applied to a tether  128  attached to a prosthetic mitral valve (not shown in  FIG. 3 ) to be anchored by the epicardial anchor device  100 . The positioning device  142  includes a handle assembly  144 , an elongate member  145 , a docking member  146 , and a tether securing member  147 . In some embodiments, the positioning device  142  can include a force sensor device  148 , which can communicate with a transducer  149 , which in turn can communicate with an electronic device  141  to display the output of the force sensor device  148 . In some embodiments, the transducer  149  can be incorporated within the force sensor device  148 . In some embodiments, the force sensor device  148  can be coupled to a data acquisition module rather than a transducer. The electronic device  141  can be, for example, a monitor or display of a computer, such as a laptop computer or a desktop computer, or a handheld electronic device such as a tablet, phone or other electronic device configured to receive and display the output of the force sensor device  148 . 
     The positioning device  142  can include other various components that can be for example coupled to or incorporated within the handle assembly  144  or another component of the positioning device  142 . The docking member  146  can be used to releasably couple the epicardial pad  100  to the positioning device  142  and can be actuated by one or more components of the positioning device  142 . The tether securing device  147  can include, for example, a vice mechanism used to lock the tether  128  at a desired position. In some embodiments, the tether securing device  147  can include a pinning device that can pierce the tether  128  to secure the tether  128  in the desired position. More detailed descriptions of various components of embodiments of a positioning device  142  are described below. 
       FIGS. 4-12  illustrate an epicardial anchor device according to an embodiment. An epicardial anchor device  200  includes a tether attachment member  224 , a pad assembly  220 , a tube member  255  and a tube cover member  256 . The tether attachment member  224  includes a base member  240 , a hub  250 , a retaining ring  252 , a locking pin assembly  226 , and a pin member  253 . The locking pin assembly  226  includes a driver portion  246  and a piercing portion  249 . The base member  940  defines a circumferential pad channel  242 , a retaining channel  251  and a locking pin channel  234 . The pad channel  242  can be used to couple the pad assembly  220  to the tether attachment member  224 . The retaining channel  251  can receive an outer edge of the retaining ring  252 , which is used to retain the hub  250  to the base member  240 . The base member  240  also defines cutouts or detents  243 , as shown for example, in  FIGS. 5, 7 and 12 . 
     The tube member  255  is coupled to the base member  240  and the base member  240 , the hub  250  and the tube member  255  collectively define a tether passageway  235  through which a tether (not shown) can be received. The cover member  256  can be formed with a fabric material, such as for example, Dacron®. The tether channel  235  intersects the locking pin channel  234  and is in fluid communication therewith. 
     The pad assembly  220  includes a top pad portion  258 , a bottom pad portion  259  and a filler member  257  disposed therebetween. The top pad portion  258  and the bottom pad portion  259  can each be formed with, for example, a flexible fabric material. The top pad portion  258  and the bottom pad portion  259  can each define a central opening through which the tube member  255  can pass through. A portion of the top pad portion  258  is received within the channel  242  of the base member  240  as shown, for example, in  FIGS. 7-9 . 
     An outer perimeter portion of the hub  250  is received within the retaining channel  251  such that the hub  250  can rotate relative to the base member  240  to actuate the locking pin assembly  226  as described in more detail below. As shown, for example, in  FIGS. 10 and 11 , the hub  250  includes arms  261  with protrusions  262 . The protrusions  262  can be received within cutouts  243  of the base member  240  and act as a stop or limit to the rotation of the hub  250 . The hub  250  defines slots  263  that enable the arms  261  to flex and allow the protrusions  262  to be moved in and out of the cutouts  243 . As shown, for example, in  FIGS. 9 and 10  the hub  950  defines a curved channel  250  on a bottom portion of the hub  950 . The curved channel  250  is asymmetrical (or spiral) and receives the driver portion  246  of the locking pin assembly  226 . As the hub  250  is rotated relative to the base member  240 , the hub  250  acts as a cam to move the locking pin assembly  226  linearly within the locking pin channel  234 . The locking pin assembly  226  can be moved from a first position in which the piercing portion  249  is disposed outside of the tether passageway  235  as shown in  FIGS. 7 and 8 , and a second position in which the piercing portion  249  extends through the tether passageway  235  as shown in  FIG. 9 . The pin member  253  (see, e.g.,  FIG. 8 ) can be formed with a metal material that is more radio-opaque than the other components of the anchor device and thus visible to the user (e.g. physician) using conventional imaging modalities to enable the user to confirm that the locking pin assembly  226  has been fully moved to the second position. 
     In use, when the locking pin assembly  226  is in the first position, a tether (not shown) coupled to, for example, a prosthetic mitral valve and extending through a puncture site in the ventricular wall of a heart can be inserted through the tether passageway  235 . The hub  250  can then be rotated 180 degrees to move the locking pin assembly  226  linearly within the locking pin channel  234  such that the piercing portion  249  extends through the tether passageway  235  and engages or pierces the tether, securing the tether to the tether attachment member  224 . For example, the hub  250  also defines a driver receiving opening  210  configured to receive a mating portion of a positioning device (described below, e.g., with reference to positioning devices  242 ,  342  and  442 ). The positioning device can be used to rotate the hub and actuate the locking pin assembly  226 . When the locking pin is in the first position, the protrusions  262  of the hub  250  are each disposed within one of the cutouts  243  of the base member  240  (i.e., a first protrusion is in a first cutout, and a second protrusion is in a second cutout). The hub  250  can then be rotated 180 degrees such that the protrusions  262  are moved out of the cutouts  243  of the base member  240  and at the end of the 180 degrees the protrusions  262  are moved into the other of the cutouts  243  of the base member  240  (i.e., the first protrusion is now in the second cutout, the second protrusion is now in the first cutout). 
     The base member  240  can also include cutout sections  266  and define side openings  267  (see, e.g.,  FIGS. 4 and 5 ) that can be used to couple a positioning device to the epicardial anchor device  200 . For example,  FIGS. 13-17B  illustrate a positioning device  242  that can be used to deploy and position an epicardial anchor device such as anchor device  200 . 
     As shown in  FIG. 13 , in this embodiment, the positioning device  242  includes an elongate member  245 , a docking member  246  coupled to a distal end of the elongate member  245 , a handle assembly  244  and a tether securing member  247 . The handle assembly  244  includes a housing  254 , a transparent tube segment  223  with indications disposed thereon, a tension member  229 , a thumb dial  227 , a release button  233  and a safety lever  231 . 
     The handle assembly  245  is coupled to the tether securing device  247  with a rod member  264  (see, e.g.,  FIG. 15 ). The handle assembly  245  is also coupled to the elongate member  245 , which is coupled to the docking member  246 . The docking member  246  includes coupling arms  236  with coupling pins  238  extending inwardly from the coupling arms  236 . The coupling pins  238  are configured to be received within the side openings  267  of the anchor device  200  described above, and the coupling arms  236  can engage the cutout sections  266  of the anchor device  200 . The coupling arms  236  have hinged joints which are coupled to a disc member  239 . The disc member  239  can be coupled to or incorporated with or monolithically formed with the elongate member  245 . A spring  216  disposed between the disc member  239  and the arms  236  biases the coupling arms  236  in a closed position as shown, for example, in  FIGS. 13, 15 and 16 . The coupling arms  236  can be moved to an open position (not shown) to allow for the anchor device  200  to be received between the coupling arms  236  to couple and release the anchor device  200  to and from the positioning device  242 . Actuation of the docking member  246  is described in more detail below. An inner driver member  217  is movably disposed within a lumen defined by the elongate member  245  and extends through the docking member  246 . The inner driver member  217  includes a shaped distal tip  237  that is configured to be matingly received within the driver receiving opening  210  of the anchor device  200 . The inner driver member  217  is operatively coupled to the thumb dial  227  of the positioning device  242  and can be used to actuate the locking pin assembly  226  of the anchor device  200  to secure a tether to the anchor device  200 , as described below. 
     The safety lever  231  is hingedly coupled to the housing  254  and can be moved from a first position as shown, for example, in  FIG. 13 , in which the safety lever  231  prevents the release button  233  from moving and a second position (not shown) in which the safety lever  231  is pivoted or moved in a direction upward away from the elongate member  245  such that the release button  233  can be moved as desired as described in more detail below. 
     In use, a tether (not shown) extending from a prosthetic mitral valve and outside of the heart can be inserted through the epicardial anchor device  200  and threaded through a lumen of the inner driver member  217 , through the handle assembly  244 , and out through the tether securing device  247 . 
     To releasably couple and uncouple the anchor device  200  to and from the positioning device  242 , the safety lever  231  is moved to its second position in which the release button  233  is free to move. The release button  233  is fixedly coupled to the elongate member  245  such that as the release button is moved distally, the elongate member  245  moves distally, and in turn the disc member  239  moves distally compressing the spring  216  and actuating the hinged coupling arms  236  of the docking member  246  to open wide enough such that the anchor device  200  can be place therebetween. The distal tip  237  of the driver member  217  is received within the opening  210  of the anchor device  200 . The release button  233  can then be moved proximally to allow the coupling arms  236  to move back to their biased closed position (e.g., closer together) and be inserted into the side openings  267  of the anchor device  200 . The safety lever  231  can then be moved back to its first position, as shown in  FIG. 13 . 
     With the anchor device  200  coupled to the positioning device  242 , the anchor device  200  can be positioned at a desired location on the outer surface of the ventricular wall of the heart, such as for example, at the apex. The tether extending through the positioning device  242  and out the proximal end of the positioning device  242  can be pulled proximally to a desired tension. When the tether is drawn/pulled to the desired tension, e.g., such that the deployed prosthetic valve seats firmly in the native annulus and any regurgitation seen on fluoroscopy or echocardiography is no longer present, the practitioner can fine tune the tensioning by visually observing the tether within the transparent tube segment  223  and compare the longitudinal distance travelled against an implant position scale. When the tether is suitably located, the locking pin assembly  226  of the anchor device  200  can be actuated by the positioning device  242  to lock the tether in place on the epicardial anchor device  200 . For example, the thumb dial  227 , which is operatively coupled to the driver member  217 , can be rotated to actuate the locking pin assembly  226  of the anchor device  200  to pierce the tether and secure the tether to the anchor device  200 . 
     Prior to pinning the tether to the anchor device  200 , it may be desirable to make small adjustments or fine tuning to the position of the anchor device  200  and/or to the tension of the tether. To make such adjustments or fine tuning, the tether securing device  247  can be used to secure the tether at a fixed position on the positioning device  242 , such that the anchor device  200  can be pushed distally snug to the outer wall of the heart. For example, in this embodiment, the tether securing device  247  includes a collet  212  (see, e.g.,  FIGS. 15 and 17A ) that provides a friction fit against the tether when the tether securing device  247  is rotated. If an adjustment to the tension of the tether and/or to the position of the anchor device  200  is desired, with the tether securing device  247  holding the tether in a fixed position, the tension member  229  can be actuated to allow the handle assembly  244 , elongate member  245  and docking member  246  to be moved distally relative to the rod member  264  to which the tether securing device  247  is coupled. For example, as shown in  FIGS. 17A and 17B , grooved teeth  265  of the rod member  264  allow the handle assembly  244  to be incrementally moved distally. Alternatively, the push buttons  219  on the tension member  229  can be depressed which will release the grooved teeth  265  and allow the handle assembly  244  to be slid freely relative to the rod member  264 . 
     When the anchor device and tether have been secured in a desired position and at a desired tension, the positioning device  242  can be actuated to pin the tether to the anchor device  200  as described above, and then the epicardial anchor device  200  can be released from the positioning device  242 . The portion of the tether extending from the anchor device  200  can be cut to a desired length and/or tied off. 
       FIGS. 18-21  illustrate another embodiment of a positioning device that can be used to position an epicardial anchor device such as anchor device  200 . As with the previous embodiment, the positioning device  342  includes an elongate member  345 , a docking member  346  coupled to a distal end of the elongate member  345 , and a handle assembly  344  coupled to the elongate member  345 . The handle assembly  344  includes a housing  354 , a transparent tube member  323  with indications disposed thereon, a tension member  329 , a thumb dial  327 , a release button  333  and a safety lever  331 . Each of these components can be the same as or similar to the corresponding components of positioning device  242  and are therefore not discussed in detail with respect to this embodiment. 
     In this embodiment, the positioning device  342  also includes a force sensor device  348  coupled at a proximal end of the positioning device  342 . The force sensor device  348  can be coupled to the housing  344  via a rod member  364  similar to the rod member  264 . The force sensor device  348  includes a sensor housing  369  defining an interior region that receives a load cell  368 . In some embodiments, the load cell can include, for example a piezoelectric sensor. In some embodiments the load cell  368  can include miniature strain gauges. The load cell  368  can be electrically coupled to a transducer (not shown) or a data acquisition module (not shown) via a cable  311 , which in turn can communicate with an electronic device (not shown) configured to display the output of the force sensor device  348  as described above with respect to  FIG. 3 . The electronic device can be, for example, a monitor or display of a computer, such as a laptop computer or a desktop computer, or a handheld electronic device such as a tablet, phone or other electronic device configured to receive and display the results of the force sensor device  348 . 
     The positioning device  342  can also include a tether securing device  347  coupled proximally to force sensor device  348 . The tether securing device  347  includes a collet (not shown) that provides a friction fit against a tether when the tether securing device  347  is rotated as described for the previous embodiment. As shown in the schematic illustration of  FIG. 21 , the rod member  364  can extend through the force sensor device  348  and the tether securing device  347  can be coupled thereto. 
     In use, as with the previous embodiment, a tether (not shown) extending from a prosthetic mitral valve and outside of the heart can be inserted through an epicardial anchor device, threaded through the elongate member  345 , through the handle assembly  344 , and out through the tether securing device  347 . The anchor device can be releasably coupled to the positioning device  342  in the same manner as described above for positioning device  242  and the locking pin assembly of the anchor device can be actuated to pin the tether to the anchor device as described above. 
     The anchor device  200  can be positioned at a desired location on the outer surface of the ventricular wall of the heart, such as for example, at the apex. The tether extending through the positioning device  342  can be pulled proximally to a desired tension. In this embodiment, the tension on the tether can be measured and displayed for the practitioner. For example, tether securing device  347  exerts a compressive force on the load cell  368  as the tether is being pulled through. The compressive force displaces the load cell, which causes a deflection of the load cell which is detected by the sensor(s) within the load cell  368 . The deflection data is sent to the data acquisition module which in turn provides pressure data to be viewed on an electronic display. When the desired tension on the tether is achieved, the tether securing device  347  can be used to secure the tether at a fixed position relative to the positioning device  342  as described above. 
     If an adjustment to the tension of the tether and/or to the position of the anchor device on the tether is desired, with the tether securing device  347  holding the tether in a fixed position, and while holding the tether securing device  347 , the tension member  329  can be actuated to allow the handle assembly  344 , elongate member  345  and docking member  346  to be moved distally relative to the rod member  364  and tether securing device  347 . For example, as previously described, the tension member  329  can be used to incrementally move the handle assembly  344  distally or push buttons  319  on the tension member  329  can be depressed which will release grooved teeth  365  on the rod member  364  and allow the handle assembly  344  to be slid freely relative to the rod member  364 . 
     When the anchor device and tether have been secured in a desired position and at a desired tension, the positioning device  442  can be actuated to release the epicardial anchor device. The portion of the tether extending from the anchor device can be cut to a desired length and/or tied off. 
       FIGS. 22-28  illustrate a positioning device  442  according to another embodiment. The positioning device  442  can be configured the same as or similar to and provide the same or similar functions as the above described embodiments. The positioning device  442  includes a docking member  446  coupled to a distal end of an elongate member  445 , a handle assembly  444  and a force sensor device  448 . The positioning device  442  can also include a tether securing device (not shown) that can be the same as or similar to the tether securing devices described above. The handle assembly  444  includes a housing  454  having a transparent segment  423  with indications disposed thereon, a tension member  429 , a switch  427 , a release button  433  and a safety lever  431 . 
     The handle assembly  445  is coupled to the elongate member  445 , which is coupled to the docking member  446 . The docking member  446  includes coupling arms  436  with coupling pins  438  extending inwardly from the coupling arms  436 . As with the previous embodiments, the coupling pins  438  are configured to be received within the side openings of an anchor device such as anchor device  200  described above. The coupling arms  436  can also engage the cutout sections of the anchor device as described above. The coupling arms  436  have hinged joints which are coupled to a disc member  439  which is coupled to or incorporated or monolithically formed with the elongate member  445 . A spring  416  is disposed between the disc member  439  and the arms  436  and biases the arms  436  in a closed position as shown, for example, in  FIGS. 13, 15 and 16 . The coupling arms  436  can be moved to an open position (not shown) to allow for the anchor device to be received between the coupling arms  436  to couple and release the anchor device to and from the positioning device  442 . Actuation of the docking member  436  is described in more detail below. An inner driver member  417  is movably disposed within a lumen defined by the elongate member  445  and extends through the docking member  446 . The inner driver member  417  includes a shaped distal tip  437  that is configured to be matingly received within a driver receiving opening of the anchor device as described above. The inner driver member  417  is operatively coupled to the switch  427  of the positioning device  442  and can be used to actuate the locking pin assembly of the anchor device to secure a tether to the anchor device, as described above for previous embodiments. 
     The safety lever  431  can be moved from a first position as shown in  FIGS. 22, 24 and 25  in which the safety lever  431  prevents the release button  433  from moving and a second position (not shown) in which the safety lever  431  is moved in a direction downward away from the elongate member  445  such that the release button  433  can be moved as desired as described in more detail below. 
     As shown in  FIGS. 26-30 , in this embodiment, the force sensor device  448  includes a sensor housing  470 , a fluid chamber  472  and a load washer  474 . The fluid chamber  472  defines an interior region that can contain a fluid and that is in fluid communication with a conduit  476 . The fluid chamber  472  is received within the sensor housing  470  and the conduit  476  extends out of the sensor housing  470  through an opening  475  defined by the sensor housing  470 . The load washer  474  is disposed over the fluid chamber  472  and is coupled to the sensor housing  470  with pins  471  such that the load washer  474  can move within slots  477  defined by the sensor housing  470 . This allows for the fluid chamber  472  to reduce and expand in size within the interior region defined collectively by the sensor housing  470  and the load washer  474 . A fluid port connector  473  is coupled to the conduit  476 . The fluid port connector  473  can be for example, a Luer connector. The fluid port connector  473  can be coupled to a pressure transducer (not shown) which in turn can be coupled to a device that can be used to display pressure readings received from the pressure transducer. In some embodiments, the pressure transducer can be incorporated within the force sensor device  448 , or coupled directly to or proximate to the force sensor device  448 . During use, force is exerted on the load washer  474  which in turn exerts a compressive force on the fluid chamber  472  causing the pressure of the fluid in the interior region of the fluid chamber  472  to be increased. This increased pressure can be communicated through the fluid from the fluid chamber  472  to and through the conduit  476 . The force sensor device  448  can be used to measure the load on a tether extending through the positioning device  442 . For example, the positioning device  442  can include a tether securing member (not shown) that can be configured the same as or similar to the tether securing device  247  described above. In a similar manner as shown for force sensor device  448  (see, e.g.,  FIG. 21 ), the rod member  464  can extend through the force sensor device  448  and the tether securing device can be coupled to the rod member  464  and disposed on a proximal side of the force sensor device  448  in contact with the load washer  474 . As the tether is pulled through to a desired tension, the tether securing device exerts a force on the load washer  474 . 
     In use, a tether (not shown) extending from a prosthetic mitral valve and outside of the heart can be inserted through an epicardial anchor device  400  (see,  FIG. 22 ) and threaded through a lumen of the inner driver member  417 , through the handle assembly  444 , and out through the tether securing device (not shown). For purposes of the following description, the epicardial anchor device  400  can be the same as the epicardial anchor device  200  described above. 
     To releasably couple and uncouple the anchor device  400  to and from the positioning device  442 , the safety lever  431  is moved to its second position in which the release button  433  is free to move. The release button  433  is fixedly coupled to the elongate member  445  such that as the release button  433  is moved distally, the elongate member  445  moves distally, and in turn the disc member  439  moves distally compressing the spring  416  and actuating the hinged coupling arms  436  of the docking member  446  to open wide enough such that the anchor device  400  can be place therebetween. The distal tip  437  of the driver member  417  is received within the mating opening of the anchor device  400  as described above for anchor device  200 . The release button  433  can then be moved proximally to allow the coupling arms  436  to move back to their biased closed position (e.g., closer together) and be inserted into the side openings of the anchor device  400 . The safety lever  431  can then be moved back to its first position, as shown in  FIGS. 24 and 25 . 
     With the anchor device  400  coupled to the positioning device  442 , the anchor device  400  can be positioned at a desired location on the outer surface of the ventricular wall of the heart, such as for example, at the apex. The tether extending through the positioning device  442  and out the proximal end of the positioning device  442  can be pulled proximally to a desired tension. When the tether is drawn/pulled to the desired tension, e.g., such that the deployed prosthetic valve seats firmly in the native annulus and any regurgitation seen on fluoroscopy or echocardiography is no longer present, the practitioner can fine tune the tensioning by visually observing the tether within the transparent segment  423  and comparing the longitudinal distance travelled against an implant position scale. Further, as shown in  FIG. 29 , the transparent segment  423  includes markings or indications  415 . In this example, the markings  415  include indications between 5 and 15 centimeters. Different indications and/or increments can be used as appropriate. A distal portion of the rod member  464  can be viewed through the transparent segment  423  and includes an indicator  418  at a distal end of the rod member  464 . The indicator  418  can be a marking on the rod member  464  or a separate component coupled to the rod member  464 . In some embodiments, the indicator  418  can be color coded. The indicator  418  shows the location of the rod member  464  as the rod member  464  is moved in a proximal and distal direction and corresponds to a distance between the bottom surface of the epicardial pad device  400  that contacts the heart and the annulus of the heart valve. For example, the markings  415  can be used to identify the location of the indicator  418  on the distal end of the rod member  464 . The distance between the bottom surface of the epicardial pad device  400  that contacts the heart and annulus of the heart can be determined based on a known length of the tether. For example, a proximal end portion of the tether extending out of the positioning device  442  can have a marker  414  (see  FIG. 39  illustrating a tether  428  with a marker  414  coupled thereto). The marker  414  can be for example, a stainless steel hypotube or band crimped or swaged onto the tether. The marker  414  on the tether can indicate a preset distance from where the prosthetic mitral valve is seated in the annulus. For example, the marker  414  can be a set distance of 40 mm from where the tether is attached at the cuff of the prosthetic mitral valve. From this, when the tether is extended through the positioning device  442 , depending on the tension applied to the tether, the location of the indicator  418  on the rod member  464  can represent the distance between the epicardial pad device  400  that contacts the heart and annulus of the heart. 
     When the tether is suitably located, the locking pin assembly of the anchor device  400  can be actuated by the positioning device  442  to lock the tether in place on the epicardial anchor device  400 . For example, the switch  427 , which is operatively coupled to the driver member  417 , can be actuated to rotate the driver member  417  and actuate the locking pin assembly of the anchor device  400  to pierce the tether and secure the tether to the anchor device  400 . In some embodiments, the switch  427  can be moved or flipped 180 degrees. For example, the driver member  417  can be moved 180 degrees to rotate the driver inward to actuate the pin locking assembly of the anchor device  400  and secure the tether, and then back 180 degrees to move the driver member  417  in the opposite direction to release the tether. 
     Prior to pinning the tether to the anchor device  400 , it may be desirable to make small adjustments or fine tuning to the position of the anchor device  400  and/or to the tension of the tether. To make such adjustments or fine tuning, the tether securing device (not shown) can be used to secure the tether at a fixed position on the positioning device  442 , such that the anchor device  400  can be pushed distally snug to the outer wall of the heart in a similar manner as described above with respect to positioning device  242 . For example, in this embodiment, the rod member  464  can move proximally and distally relative to the handle assembly  444 . While holding the tether securing device, the tension member  429  can be actuated (e.g., rotated) such that the rod member  464  rotates proximally with the tether securing device (not shown). For example, the tension member  429  can be coupled to the rod member  464  such that rotating of the tension member  429  causes the rod member to move proximally or distally depending on the direction of rotation of the tension member  429 . This can provide the ability to make fine adjustments to the tension on the tether. In addition, the release button(s)  419  on the tension member  429  can be pressed to allow the tension member  429  to disengage from the teeth  465  of the rod member  464  and be freely slid relative to the rod member  464 . In this manner, the tension member  429  can be slid distally, which in turn moves the handle assembly  444 , elongate member  445  and docking member  446  distally relative to the rod member  464  and tether securing device. 
     As with the previous embodiment, the tension on the tether can be measured and displayed for the practitioner via the force sensor device  448 . For example, as described above, the tether securing device (not shown) can exert a compressive force on the load washer  474  as the tether is being pulled through. 
     When the anchor device and tether have been secured in a desired position and at a desired tension, the positioning device  442  can be actuated to pin the tether to the anchor device  400  as described above, and then the epicardial anchor device  400  can be released from the positioning device  442 . The portion of the tether extending from the anchor device  400  can be cut to a desired length and/or tied off. 
       FIG. 31  illustrates a tension limiting device (also referred to as “tensioner”) that can be included in the positioning devices described herein. The tensioner  480  can be incorporated within, for example, the tension member  429 ′ and can be used to limit the amount of load (e.g. tension T) that can be set during prosthetic valve implantation. The tensioner  480  includes ratchet members  478  and  479  that skip over each other when maximum tension on the lead screw is achieved. A spring  483  is coupled to the rod member  464  and applies tension on the ratchet members  478  and  479 . The ratchet member  479  can be coupled to the housing of the tension member  429  and can move axially along the rod member  464 . The ratchet member  478  includes inner teeth that engage the teeth  465  of the rod member  464  such that the ratchet member  478  can be moved along the rod member  464  as the tension member  429  is rotated. For example, as the tension member  429  is rotated to adjust the tension on the tether, the ratchet member  479  will move with the tension member  429  and the ratchet member  478  will slide relative to the ratchet member  479  until the tension on the tether exceeds a set value, at which point the tensioner  480  will act like a slip clutch, preventing further tensioning. The tension limit can be a preset value of the device or can be set according to the particular procedure and/or patient. 
       FIGS. 36 and 37  illustrate an alternative embodiment of a force sensor device  648  that can be included on a positioning device described herein. The force sensor device  648  is similar to the force sensor device  448  and can function in the same or similar manner as the force sensor device  448 . The force sensor device  648  includes a sensor housing  670 , a fluid chamber  672  and a load washer  674 . The fluid chamber  672  defines an interior region that can contain a fluid and that is in fluid communication with a conduit  676 . The fluid chamber  672  is received within the sensor housing  670  and the conduit  676  extends out of the sensor housing  670  through an opening  675  defined by the sensor housing  670 . The load washer  674  is disposed over the fluid chamber  672  and is coupled to the sensor housing  670  with a retainer  686  such that the load washer  674  can move or float relative to the sensor housing  670 . For example, the load washer includes a perimeter flange (not shown) on which the retainer  686  rests on top of the sensor housing  670 . This allows for the fluid chamber  672  to reduce and expand in size within the interior region defined collectively by the sensor housing  670  and the load washer  674 . A spring  688  and adjuster screw  684  are disposed within an opening  690  ( FIG. 38 ) defined in the sensor housing  670  and can be used to tune the pressure reading at a fixed load. The opening  690  is also used to couple the force sensor device  648  to a rod member (e.g.,  464 ) of a positioning device (e.g.,  642 ). 
     In this embodiment, a tether (not shown) extending through the positioning device to which the force sensor device  648  is coupled, extends through the rod member of the positioning device, through the adjuster screw  684  and spring  688 , through load washer  674  and out a proximal opening  691  defined in the load washer  674  at a proximal end of the force sensor device  648 . In this embodiment, a pinning mechanism incorporated into the force sensor device  648  can be used to pierce the tether and secure the tether to the force sensor device  648 . The pinning mechanism includes a pin holder  685  coupled to a pin  687 . The pin holder  685  can be manually moved inward to actuate or move the pin  687  inwardly into the opening  691  (see, e.g.,  FIG. 38 ) to pierce a tether extending therethrough. 
     A fluid port connector  673  is coupled to the conduit  676 . The fluid port connector  673  can be for example, a Luer connector. The fluid port connector  673  can be coupled to a pressure transducer  649  via a conduit (not shown) which is disposed within a holder portion  689  defined in the sensor housing  670 . The pressure transducer  649  being incorporated within the force sensor device  648  can compensate for tool height changes during a procedure that could change the pressure reading. The pressure transducer  649  can in turn be coupled to a device that can be used to display pressure readings received from the pressure transducer  649 . 
     In this embodiment, during use, when the tether is pierced by the pin  687 , the load is transferred to the load washer  674 , which in turn exerts a compressive force on the fluid chamber  672  causing the pressure of the fluid in the interior region of the fluid chamber  672  to be increased. This increased pressure can be communicated through the fluid from the fluid chamber  672  to and through the conduit  676  and to the pressure transducer  649  via a conduit (not shown) connecting the conduit  676  to the pressure transducer  649  via the connector  673 . The force sensor device  648  can be used to measure the load on a tether extending through the positioning device to which the force sensor device  648  is coupled. 
     For each of the embodiments of a positioning device described herein ( 242 ,  342 ,  442 ), in some cases, after deployment, the tether may be left having excess length, i.e. not trimmed, in order to facilitate later capture if necessary. If it is determined that the length of the tether is not suitable for some reason, e.g., regurgitation is seen post-procedure and the tether is too slack or the tension is too high and the apical tissue is invaginating or changing the shape of the heart in an unwanted manner, the positioning device can be used to capture the excess untrimmed tail of the tether, thread the tether through the positioning device, re-engage the epicardial anchor device, unlocking the pin assembly of anchor device and allowing for the tether length adjustment. The tether may then be adjusted length-wise, either shorter or longer, and the tether is then re-tested for tensioning force, re-pinned and locked into place with the epicardial anchor device. 
     In some cases, tether tightening or shortening may be, for example, in the range from about 1 mm-10 mm, or about 1 mm-8 mm, or about 1 mm-5 mm, or about 2 mm-8 mm, or about 2 mm-5 mm in length, and all ranges inclusive. Tether loosening or lengthening is contemplated as ranging from about 1 mm-10 mm, or about 1 mm-8 mm, or about 1 mm-5 mm, or about 2 mm-8 mm, or about 2 mm-5 mm in length and all ranges inclusive. 
     It is contemplated that the time range for which post-deployment adjustments to the tether length or position can be, for example, from about 0.5 hours-48 hours, or from about 24 hours-72 hours, or from about 1 day-7 days, or from about 1 day-15 days, or from about 1 day-30 days, post-implantation. 
     In an alternative embodiment of a positioning device, a force sensor device can be included that includes a mechanical indicator. For example, a spring device may be connected to a mechanical tension meter to show load range. A load of 1-2 lbs. or 1-4 lbs. are examples of a typical target load. 
     Although not shown, an alternative to the vice type of tether securing device described herein (e.g.,  247 ,  347 ), a pinning device that can be used. For example, such a device can include a portion through which the tether can be threaded, and a pin member can be operatively coupled thereto and actuated to pierce through the tether to hold the tether in position. Such a device can be incorporated into a positioning device and be operatively coupled to an actuation mechanism. In some embodiments, such a pinning mechanism can be manually actuated. 
       FIGS. 32-35  illustrate an alternate embodiment of a tether release tool that can be used for capturing a tether, and engaging/re-engaging an epicardial pad after it has been deployed. As shown, for example, in  FIGS. 32 and 33 , the tether release tool  580  includes a handle  581  coupled to an elongate positioning rod  582 . The positioning rod  582  includes a shaped anchor engagement tip  583  and defines a tether capture/recapture access port  584 . As shown in  FIG. 33 , the anchor engagement tip  583  is shaped to be received in a corresponding mating opening  510  of an epicardial anchor device  500  (see,  FIGS. 34 and 35 ), which can be configured the same and function the same as the epicardial anchor device  200  described above. The engagement tip  583  defines an opening  585  that is in fluid communication with the access port  584 . 
     After the epicardial anchor device  500  has been deployed and the tether  528  has been pinned to the anchor device  500 , the tether release tool  580  can be used to release the tether to allow the practitioner to make adjustments to the tension on the tether  528  and/or to the position of the anchor device  500 . As shown in  FIGS. 34 and 35 , a portion of the tether  528  extending from the anchor device  528  is inserted through the distal opening  585  and out through the access port  584 . The engagement tip  583  can be inserted into the mating opening  510  of the anchor device  500 . The tether release tool  580  can be rotated to unlock the locking assembly of the anchor device  500  to release the tether  528  from the anchor device  500 . With the tether  528  released, the tension on the tether can be adjusted and/or the position of the anchor device  500  on the heart can be adjusted and then the tether release tool  580  can be used to re-pin the tether  528  to the anchor device. For example, the engagement tip  583  can be inserted into the mating opening  510  of the anchor device  500  and rotated the opposite direction to re-actuate the locking pin assembly of the anchor device  500  and pin the tether  528  to the anchor device  500 . 
     In some embodiments, there is a tether-bundle that attaches to the extended points (two or three or four) of the stent and which converge to a central nexus point to which the adjustable tether is attached and leads to the apical tissue anchor location within the heart. In some embodiments, the tether extends downward through the left ventricle, exiting the left ventricle at the apex of the heart to be fastened on the epicardial surface outside of the heart. Similar anchoring is contemplated herein as it regards the tricuspid, or other valve structure requiring a prosthetic. 
     As described herein, during deployment of a prosthetic heart valve, the operator is able to adjust or customize the tethers to the correct length for a particular patient&#39;s anatomy. The tethers also allow the operator to tighten the cuff onto the tissue around the valvular annulus by pulling the tethers, which creates a leak-free seal. In some embodiments, the tethers are optionally anchored to other tissue locations depending on the particular application of the prosthetic heart valve. In the case of a mitral valve, or the tricuspid valve, there are optionally one or more tethers anchored to one or both papillary muscles, septum, and/or ventricular wall. 
     The tethers, in conjunction with the cuff of the valve, provide for a compliant valve which has heretofore not been available. The tethers can be made from surgical-grade materials such as biocompatible polymer suture material. Examples of such material include 2-0 exPFTE (polytetrafluoroethylene) or 2-0 polypropylene. In one embodiment, the tethers are inelastic. It is also contemplated that one or more of the tethers may optionally be elastic to provide an even further degree of compliance of the valve during the cardiac cycle. In some embodiments the tether(s) may be bioresorbable/bioabsorbable and thereby provide temporary fixation until other types of fixation take hold such a biological fibrous adhesion between the tissues and prosthesis and/or radial compression from a reduction in the degree of heart chamber dilation. 
     While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. Where methods described above indicate certain events occurring in certain order, the ordering of certain events may be modified. Additionally, certain of the events may be performed concurrently in a parallel process when possible, as well as performed sequentially as described above 
     Where schematics and/or embodiments described above indicate certain components arranged in certain orientations or positions, the arrangement of components may be modified. While the embodiments have been particularly shown and described, it will be understood that various changes in form and details may be made. Any portion of the apparatus and/or methods described herein may be combined in any combination, except mutually exclusive combinations. The embodiments described herein can include various combinations and/or sub-combinations of the functions, components, and/or features of the different embodiments described. For example, although not necessarily described for each embodiment, the various positioning devices ( 242 ,  342 ,  442 ) can include any features and or functions described herein for the various embodiments.