The present invention relates to a catheter for manipulating a medical implant in a human or animal tissue, a medical implant, in particular a leadless pacemaker, having a fastening arrangement for interaction with a catheter, and a system comprising a catheter and a medical implant.
The installation of leadless pacemakers demands surgical procedures that employ catheter-based tooling support. Such installations widely differ from the pocket-based patient interfacing associated with the implantation of traditional lead-based pacemakers. For repositioning, and especially for explanting a leadless pacemaker, a different tool has to be introduced into the body. In many cases, it is desirable to introduce the pacemaker through the femoral and not the jugular vasculature, which requires a high flexibility of the catheter.
In U.S. Pat. No. 3,835,864 a catheter is described which is used to implant an intracardiac stimulator through the jugularis.
International Publication No. WO/2012/082755 describes a catheter system for retrieving a leadless cardiac pacemaker from a patient. The catheter is not suitable for implantation of the implant.
The present invention is directed toward overcoming one or more of the above-mentioned problems.
It is an object of the present invention to provide a medical implant which can be delivered, implanted, repositioned as well as recaptured or explanted with the same catheter tooling.
Another object of the present invention is to provide a catheter for a medical implant, in particular a leadless pacemaker, which allows for delivery, implant, reposition as well as recapture of the medical implant.
Another object is to provide a system comprising a catheter and a medical implant where delivery, implant, reposition and recapture or explant of the medical implant can be performed.
At least the above objects are achieved by the features of the independent claim(s). The other claims, the description and the drawings disclose favorable embodiments of the present invention.
According to a first aspect of the present invention, a medical implant is proposed, for introduction into a human or animal tissue, in particular a leadless pacemaker, having a distal end and an opposing proximal end with a rigid fastener provided for interaction with a coupling element of a catheter and protruding from the proximal end in direction of a longitudinal axis of the implant, the fastener being rigidly attached to the implant. Preferably the fastener is configured for a rigid primary engagement with a coupling element of the catheter in a primary engagement mode of operation, as well as to provide an interface for attaching an element provided by the catheter for a tether mode of operation and for recapturing the medical implant after the medical implant being released from catheter.
The medical implant interacts with the catheter in different modes. In a primary engagement mode, the medical implant is intimately connected to a coupling element at the catheter distal tip, for instance in a key and lock structure, and may be advanced in the blood vessel and rotated to move the implant anchor, e.g., a helix, into or out of the tissue. In a tethering mode, the medical implant is released from the intimate connection to the catheter distal tip during the primary engagement mode of operation, but connected via a wire loop, such as a lasso or snare, or other connection elements in order to test the location and functions of the medical implant before completely releasing it from the catheter. Further, the fastener additionally provides the possibility for attaching an element, for recapturing the medical implant, and for repositioning or explantation of the medical implant. The wire loop may be made of Nitinol, tungsten, or any other biocompatible material, such as, for example, a metal, a polymer, or otherwise.
Favorably, the present invention is suitable for helix-based or side hooks medical implants, i.e., where the medical implant is anchored in the tissue by rotating the implant and/or the helix so that the helix or side hooks advances into the tissue.
In particular for leadless pacemaker implantation and acute explantation procedures, femorally-routed catheter-based tooling support is employed. The present invention solves the pivotal need to these processes for a reliable and robust interface between the medical implant and the implant/explant catheter.
The fastener of the medical implant is preferably a hitch geometry, so that a suite of engineered hitch geometries presented by the medical implant's distal terminus may provide adequate “hand shaking” with the implant/explant catheter such that torque translation in the primary engagement mode, tether modes, full decoupling, and device recapture are appropriately coordinated with various catheter articulations. Accompanying these catheter interaction needs, the hitch geometries furthermore provide topologies that mitigate risks for trauma, thrombogenesis, and/or entanglement in patient anatomical constructs.
The implant fastener geometries provide unique capabilities for translating torque from catheter-based implant and acute explant tools while simultaneously supporting device recapture needs. The spectrum of geometries employs minimal components, offers flexibilities for ensuring long-axis alignment between the implant and the catheter to aid in transitioning between tether-supported and primary engagements (i.e., avoiding snagging), and presents geometries to mitigate risks for either entanglement in chordae tendineae or heart wall irritation.
Due to an array of implementation complexities, leadless pacer geometric configurations, and broad-spectrum system design choices, implementing a combination tool that facilitates both implant and acute explant procedures has not been proposed nor realized within the leadless pacing field.
Favorably, a lasso-reliant implementation can be achieved which maintains an interface with the affiliated catheter, thus enabling torque translation in order to insert helix-based device anchors of the medical implant into the tissue and enabling a tether mode for decoupling the medical implant from the catheter's torque delivery mechanism in prescriptive fashion. Further, recapturing the medical implant for implant relocation and acute extraction procedures is possible with the same catheter.
According to a favorable embodiment of the present invention, the fastener may comprise a divot structure which allows the tether element and/or an element for recapturing, for instance the wire loop, such as a snare or lasso, when attached to the fastener, to align with the longitudinal axis of the medical implant, at least virtually, when the tether element is set under tension. The divot structure favorably avoids an undue eccentricity between the catheter distal tip and the medical implant because tightening of the wire loop does not cause a misalignment of the long axes of either the catheter or the medical implant. Such an undesired misalignment presents a snagging potential and can cause complications for transitioning from a tethered connection to a more robust primary engagement of the medical implant with the catheter. Primary attachments are especially valuable for designs where the device anchor demands torque translation throughout the length of the catheter to properly imbed the implant within patient myocardium.
Advantageously, the fastener incorporates a series of divots that provide a pathway for a wire loop to align into the hitch. In some cases, it may be preferred that the entire hitch be captured by the lasso, while other designs may permit the recapture of just a single lobe of the implant hitch. For cases where single lobes are captured, the geometries may blossom outward to bias the lasso loop to align as close to the center axis of the implant as possible and avoid slipping off. This alignment aids in offsetting the snagging risks as the device is recaptured and transitioned from tethered interactions toward a primary engagement. Each design additionally offers smooth geometric features to patient anatomy and lacks grossly overhanging features that would tend to permanently bind with patient valving, trabeculae, and/or chordae tendineae.
According to a favorable embodiment of the present invention, the fastener may have generally a T-form, comprising a post attached to the proximal end and aligned with the longitudinal axis of the implant, and at least one cross piece arranged fixedly at the post crosswise to the longitudinal axis, wherein the divot structure is arranged in the cross piece. In particular, the cross piece may comprise at least one lobe. Advantageously, the cross piece may be attached to the post symmetrically. In some embodiments, the cross piece may have a two-lobe configuration. Additionally, the cross piece may have an oval football configuration. In a two-lobe configuration, the fastener presents larger radii of curvature to the patient anatomy than the football design. In another embodiments, the cross piece may have a three-lobe or a four-lobe configuration. Favorably, the cross piece may have a rounded tip at its free ends in a radial direction. Further, the cross piece may have a swollen tips to prevent the wire loop from slipping off, particularly upon cinching.
According to a favorable embodiment of the present invention, the cross piece may provide a planar surface at its free end in longitudinal direction. Such a planar, table-like surface aids in transitioning from a tether mode to primary engagements with the catheter.
Rather than demanding a separate contoured feature along the housing of the medical implant to ensure lock and key mating with the catheter upon primary engagement, the configuration of each fastener and its rigidity allows for direct torque translation interfacing through the hitch. As an added bonus, in the case of the 2-lobe, 4-lobe, and certain hook hitch designs, the mating geometries within the implant/explant catheter can be identical since the plan-view footprint of the hook and 2-lobe design are subsets of a 4-lobe configuration. Such a condition means that the implant/explant tooling can be built using a 4-lobe interface, and implants can be built with either hook, 2-lobe, or 4-lobe “hitches”. The implant/explant tooling does not have to be redesigned.
According to a favorable embodiment of the present invention, the fastener may provide a twist-lock connection structure, such as, for example, a bayonet-like structure for interaction with a corresponding element of the catheter. A twist-lock connection is engaged by being pushed into a socket and then twisted to lock it in place. In another additional or alternative embodiment, the fastener may provide a fastening threaded element, like a fastening screw hole. In particular, the fastening screw hole may provide a central thread for attaching a corresponding threaded element of the catheter. The central thread may be configured as a threaded hole and the corresponding threaded element as a screw. Alternatively, the central thread may be configured as a screw and the corresponding threaded element as a threaded hole. The connection between threaded hole and screw may be utilized to tether the medical implant. A torque coil in the catheter may be used to tether which has the property of bending flexibility and yet can still be torqued with a 1:1 ratio between proximal and distal ends of the catheter.
According to a favorable embodiment of the present invention, the fastener may be configured as a mushroom-like hitch having grooves at the outside. In addition, the aforementioned central threaded opening or screw for attaching a corresponding threaded element of the catheter can be incorporated in the hitch. The cross piece may be shaped as a convex spherical part attached to the post. Favorably, the grooves may be used to interact with a corresponding element, such as, for example, a rotating cup, at the catheter either to prevent axial rotation or to impart axial rotation. The rotating cup may be connected to a torque coil slightly larger than the torque coil used for tethering described above.
According to a favorable embodiment of the present invention, one or more wire loops may protrude from the proximal end of the implant. This allows for recapturing and explantation of a medical implant in a chronic phase, i.e., several weeks after implantation when the medical implant may already be encapsulated in the patient's tissue. Favorably, the wire loops may consist of thin, flexible, radio-opaque material protruding axially and then curving radially away from the axis of the medical implant. The degree to which the flexible wire loops protrude from the medial implant greatly increases the ease of recapturing the wire loops with the catheter. The thin, flexible construction minimizes hemodynamic interference and potential damage to nearby tissue and limits the encapsulation response of the host tissue.
According to a favorable embodiment of the present invention, the fastener may be a fin. The fin allows for primary engagement with a gripper tool.
According to a favorable embodiment of the present invention, the fastener may be a simple coat hanger type structure. The hook provides a notch undercut that allows for an easier recapture with the wire loop from all sides. In other words, recapture can be safely performed virtually independent from the implant and tooling relative rotational states. Further, the undercut feature of the hook supports wire loop engagement and allows for favorable axial alignment with the catheter, i.e., with minimal offset.
According to another aspect of the present invention, a catheter is proposed for handling a medical implant in a human or animal body, in particular a medical implant according to any one of the features described above, the catheter having a handle at its proximal end and a coupling element at its distal end, the coupling element being configured to provide torque to the implant for attaching the medical implant to the body tissue at a desired location in the human or animal body and for detaching, like repositioning and/or explanting, the medical implant from the human or animal body, wherein concentric sheaths are provided with an outer sheath, an inner sheath, a torque translation sheath and a cinching sheath.
In all disclosed embodiments, one or more from the group of the outer sheath, the inner sheath, the torque translation sheath and the cinching sheath may be configured to be steerable. In some embodiments, the outer sheath may be a steerable outer sheath. In some embodiments, the inner sheath may be a steerable inner sheath. In some embodiments, the outer sheath as well as the inner sheath may be steerable sheaths. In another embodiments either the inner, outer, or both sheaths are steerable in two directions. In this embodiment, two pull wires are used, one for bending the sheath, and one for straightening it. In a further embodiment, at least one of inner or outer sheath is steerable in one direction. In this embodiment, only one pull wire is used to bend one of those sheaths and passive straitening of that sheath by reducing tension on the one pull wire. In this case, the material of the steerable catheter is pre-loaded, so that it bends back in the original shape after reducing the tension. In still other embodiments, the inner sheath, the outer sheath, or both may be pre-formed to have a natural curve. In another embodiment, at least one of the sheaths is both preformed to have a natural curve in one location and is steerable in a second location.
In other words, a concept of a single tool is proposed that merges both implantation and acute and chronic device extraction support. It is of advantage that only few components are necessary. The larger the component count, the more opportunities a design offers to the end user for realized failure. Additionally, the grooves and contours present on known medical implant structures offer an increased risk for bacterial growth and/or thrombogenesis.
Implanting, repositioning, and explanting a medical implant, such as intracardiac leadless pacemakers, is challenging for several reasons. Firstly, all mechanical interactions with the medical implant must occur via a catheter; secondly, the mechanism used to implant the medical implant (e.g., screwing a helix into the myocardium) must be reversible for repositioning or removal; thirdly, unintended tissue damage (e.g., chordae tendinae, valves leaflets, heart walls) by the medical implant or catheter must be avoided; fourthly, the natural, fibrotic capsule generated by the host tissue must be bypassed to remove a chronic implant; fifthly, the implant/explant system should allow for communications with the medical implant during implant/explant with minimal interference or signal attenuation; and sixthly, the implant/explant system must allow for the implant to make pacing threshold, sensing and impedance measurements before the medical implant is released. In some embodiments, electrical interactions with the implant may also occur via the catheter.
Favorably, a lasso-reliant implementation can be achieved which maintains an interface with the affiliated catheter, thus enabling torque translation in order to insert helix-based device anchors of the medical implant into the tissue and enabling a tether mode for decoupling the medical implant from the catheter's torque delivery mechanism in prescriptive fashion. Further, recapturing the medical implant for implant relocation and acute extraction procedures is possible with the same catheter.
Having a steerable inner sheath and a separate steerable outer sheath enables the steering of the medical implant attached to the catheter in two independent planes, being particularly advantageous for femoral routing of the catheter into the ventricle.
According to a favorable embodiment of the present invention, a wire element may be arranged inside the cinching sheath, the wire element providing a wire loop for capturing a fastener of the implant. The wire element has the wire loop at its free end. By moving the cinching sheath along the wire element, the wire loop can be enlarged or diminished and, when attached to the fastener of the medical implant, thus safely connected to the fastener with the cinching sheath close to the medical implant. The fastener may be locked to a key and lock structure of a coupling element of the torque translation sheath with the wire loop fixed to the fastener when the cinching sheath is retracted into the torque translation sheath. As a result, torque can be transmitted to the medical implant in this primary engagement mode and the helix of the medical implant arranged at its distal end can be turned and either removed from the tissue for releasing the medical implant from the tissue or for screwing it into the tissue for anchoring the medical implant at its location.
According to a favorable embodiment of the present invention, the torque translation sheath and the cinching sheath may be configured to be completely retractable into the inner sheath. The inner sheath, the torque translation sheath and the cinching sheath may be configured to be completely or partially retractable into the outer sheath. It increases the patient's safety, if all catheter components arranged inside the inner sheath are retracted in the inner sheath or proximally out of the inner sheath. Once the outer sheath has bent into the heart, the medical implant can then be advanced to follow the curve of the outer sheath.
According to a favorable embodiment of the present invention, the torque translation sheath may be provided with a key and lock structure as a coupling element at its distal end, which key and lock structure is configured to cooperate with a fastener of the implant for transmitting torque to the implant. The key and lock structure is advantageous for re-establishing interfacing between catheter and the fastener of the medical implant in the transition from a tether mode to a primary engagement mode. In the re-enabled primary engagement mode, the longitudinal axes of the catheter distal tip and the medical implant are collinear and virtually aligned. The tip of the inner sheath, which may be steerable, may advantageously provide special features that guide the medical implant into the primary engagement during transitions for tether modes. Such features can manifest tip flaring or other geometries that can collapse when the inner sheath is later pulled into the outer sheath (which also may be steerable), without influencing the outer tooling diameter. Alternatively, the tip of the inner sheath may be fluted with groves to help align (either translationally or rotationally or both) the key and lock structure as the medical implant is pulled into the catheter during recapture. Preferentially, the keyed interface on the catheter can freely rotate so that it will turn to align with the key on the medical device, thus avoiding unintentional dislodgement of the implant or tissue damage that may occur if the medical implant rotates.
According to a favorable embodiment of the present invention, the coupling element may be configured as a cup with a twist-lock internal structure for interacting with a fastener of the implant. Alternatively or additionally, the coupling element may be configured as a central thread, preferably a central screw or a central screw hole, for attaching a corresponding fastening threaded element of the implant (10). The medical implant may be tethered via the central screw and threaded hole in a tethering mode.
According to a favorable embodiment of the present invention, the coupling element may be configured as a gripper. The gripper may be attached with its fingers to a finlike fastener of the medical implant. The fingers close when being pulled toward the sheath they are protruding from, gripping the fin-like fastener.
According to a favorable embodiment of the present invention, a slider/rotator element may be provided at the handle for activating the coupling element, the slider/rotator element being aligned with a longitudinal axis of the catheter. The arrangement facilitates manipulation of the coupling element.
According to another aspect of the present invention, a system is proposed comprising a catheter according to one aspect of the present invention and a medical implant according to another aspect of the present invention, where the catheter is configured to implant and recapture and/or explant the medical implant.
Favorably, a central problem to the realization of a viable leadless pacemaker design is solved as the capacity to reliably interface the implant with an affiliated catheter-based delivery and explant tooling solution is provided. As such, the distal terminus of the medical implant presents an appropriate geometry and mechanical hardware to support a robust primary connection to the implant/explant catheter; a functional tether-mode secondary connection to the implant/explant catheter; an ability to fully decouple from the implant/explant catheter and render non-irritating and non-trombogenic surfaces to patient anatomy with minimal risks for chordae tendineae entanglement, as well as device recapture in cases where repositioning or explantation are required. Advantageously, the proposed fastener configurations satisfy these demands when specifically paired with a single-tool, combined, lasso-reliant implant/explant catheter.
According to a favorable embodiment of the present invention, one or more sheaths may be provided for covering the medical implant during implantation and/or after recapture.
According to another aspect of the present invention, a method for implantation and/or explantation of a medical implant, in particular a leadless pacemaker, into a human or animal body via a catheter is proposed, comprising the steps: obtaining access to patient vasculature; routing medical implant to implantation location and install implant; assessing medical implant operation and patient interfacing in a tether mode of the implant; and releasing medical implant from catheter. In case a problem is detected with the medical implant, the method further comprising recapturing the medical implant and either re-installing the medical implant at another location; or explanting the medical implant.
Generally, the present invention reduces or avoids unnecessary material and production cost; inventory management and parts storage; separate tools for implant and recapture; multiple insertion, routing, and removal sequences during a single clinical procedure; added training for the operation of separate tools; and a need for developing/maintaining blood-tight valving at locations where different types of hardware enter the patient vasculature. A helix-based anchor for the medical implant is possible and critical stiffness requirements do not interfere with medical implant positioning articulations/accuracy.
A change between a catheter used for delivery and a catheter used for recapture or explantation is not necessary. In particular, leadless pacemaker implantation and acute explantation procedures employ catheter-based tooling support. The lengthy and somewhat torturous paths associated with the affiliated device installation and removal processes is improved by minimizing the number of instances between the commencement and completion of a given surgery where catheter-based tooling is inserted into, steered through, and removed from patient vasculature. The present invention explores a strategy for supporting both implantation and acute extraction needs by merging such capabilities into a single tool—avoiding a need for and the risks associated with swapping between separate hardware. Further added benefits are savings on tooling development costs; eliminating a need for clinicians to interface with and learn multiple tool sets; adequately servicing use cases where leadless pacemaker implantation and acute extraction procedures occur within a common outpatient operation; and helping to reduce the risk of infection and other adverse events by minimizing the number of tools that need to be swapped in and out of the patients during the procedure.
According to a favorable embodiment of the present invention, the medical implant may be covered with an inner sheath during implantation and/or after recapture and/or during explantation, thus protecting the patient and facilitating manipulating the medical implant. This inner sheath may also be steerable.
According to a favorable embodiment of the present invention, the medical implant may be locked to the catheter in a primary engagement mode of operation and applying torque to the medical implant for rotating the medical implant. In particular, the medical implant may be held firmly against a key and lock structure of the catheter by tension applied to a wire element arranged in the catheter.
According to a favorable embodiment of the present invention, the medical implant may be disengaged from the key and lock structure and maintain the wire element connected to the medical implant in the tether mode of operation. A secure tether mode is possible, making the process more efficient and improving the given surgery.
According to another aspect of the present invention, a method for explantation of a medical implant is proposed, in particular a leadless pacemaker, having been implanted in a human or animal body, comprising the steps obtaining access to patient vasculature; accessing the medical implant with a catheter, the catheter having a handle at its proximal end and a coupling element at its distal end, the coupling element being configured to provide torque to the implant for explanting the medical implant; recapturing the medical implant; and explanting the medical implant.
According to a favorable embodiment of the present invention, the medical implant may be covered with an inner sheath after recapture and/or during explantation, thus protecting the patient and facilitating manipulating the medical implant. This inner sheath may also be steerable.
According to a favorable embodiment of the present invention, the medical implant may be locked to the catheter in a primary engagement mode of operation and applying torque to the medical implant for rotating the medical implant. In particular, the medical implant may be held firmly against a key and lock structure of the catheter by tension applied to a wire element arranged in the catheter.
Further embodiments, features, aspects, objects, advantages, and possible applications of the present invention could be learned from the following description, in combination with the Figures, and the appended claims.
The present invention together with the above-mentioned and other objects and advantages may best be understood from the following detailed description of the embodiments, but not restricted to the embodiments, wherein is shown in:
In the drawings, like elements are referred to with equal reference numerals. The drawings are merely schematic representations, not intended to portray specific parameters of the present invention. Moreover, the drawings are intended to depict only typical exemplary embodiments of the present invention and, therefore, should not be considered as limiting the scope of the present invention.
The medical implant 10 has a distal end 14 and a proximal end 12. The distal end 14 can be attached to the surrounding tissue (not shown) by means of an anchor such as a helix or the like (not shown) which can be screwed into the tissue (not shown) by rotating the medical implant 10. The catheter 100 is provided to advance the medical implant 10 and to rotate the medical implant 10. In order to transmit torque to the medical implant 10, the medical implant 10 is intimately attached to a coupling element 300 at the catheter distal tip via a fastener 20 arranged at the proximal end 12 of the medical implant 10. In this embodiment, the fastener 20 is a modified flat fin, but may be a ball, a flexible neck or the like. For the fin as fastener 20, the coupling element 300 may be a gripper 138 protruding from a metal tip 150. The gripper 138 is closed or opened by action of a gripper sheath 130.
The fin has two notches which allow for a secure attachment of the gripper without excessive compression. Each of the fingers of the gripper 138 has two appendages at its fingertip. When the fingers are pulled toward the gripper sheath 130, the gripper 138 closes while gripping the flat fin. The finger appendages prevent accidental dislodgement. A protection sheath 124 is then pushed distally with a protection sheath actuator 122, e.g., a slider, arranged at the handle 110 to cover the catheter distal tip as well as the medical implant 10, thus covering any sharp elements of the medical implant 10. The gripper torsion coil 136 and its sheath 130 are housed in a steerable sheath 140. Inside the steerable sheath 140, the large center lumen houses the gripper torsion coil 136 in its sheath 130, and two small lumen arranged diametrically outside the gripper sheath 130 house the steering wires 120 of the steerable sheath 140 which are activated by a steering actuator 116 at the handle 110. A reinforced tube is provided as an outer sheath 118 of the catheter 100.
The handle 110 depicted in
The mushroom-like fastener 20 consists of a post 24 attached to the proximal end 12 of the medical implant 10. A cup-like cross piece 30 with its convex side pointing away from the proximal end 12 has a multitude of divots 32 in its outer convex surface. The cup-like cross piece with divots 32 presents a gear structure 50, e.g., a twist-lock connection structure, for interaction with a corresponding element 300 of the catheter 100. The cup-like corresponding element 300 provides protrusions 302 protruding from its inner surface which fit in divots 32 of the fastener 20. A threaded element like a screw 310 can penetrate through a central opening 304 in the element 300 for contacting the threaded hole 52 in the fastener 20. The hole 52 may be shallow with a depth between 1 mm to 2 mm, preferably between 1 mm and 1.5 mm.
Further, the divots 32 may be used to accommodate a wire loop in a recapture and/or tether mode when the wire loop is arranged around the post 24 and tensioned. This allows for an alignment of the longitudinal axes of the medical implant 10 and the catheter distal tip with minimal eccentricity. A protection sheath 122 may cover the medical implant 10 and the catheter 100.
The mushroom-like fastener 20 has a threaded hole 52 in its center. The catheter 100 can be connected to the fastener 20 by screwing a screw 310 into the threaded hole 52. This connection allows to tether the medical implant 10. A first torque coil 126 with the screw 310 at its distal end may be used to tether the medical implant 10, where the torque coil 126 provides sufficient bending flexibility and at the same time can still be torqued with a 1:1 ratio between its proximal and distal ends. In a favorable embodiment, for ensuring that the medical implant 10 is not unscrewed from the tissue when releasing the medical implant 10, two torque coils are employed, one for releasing the medical implant 10, and a second for keeping the medical implant 10 from unscrewing from tissue. These would be nested torque coils, one very small to be the tether, and that is inside a larger one which screws the medical implant 10 in and out of tissue, and keeps it from rotating when the inner torque coil is turned.
The cup-like element 300 may be also attached to one or more torque coils 128 arranged outside the first torque coil 126. These torque coils 128 may consist of two or three opposing wound wires. The catheter 100 may be similar to the catheter described in
In alternative embodiments,
The catheter 100 may be configured in similar way as described in
It is possible to combine the implantation tools described in
The steerable catheter 100 as described above has the advantages that it may be used as an implantation/explantation catheter from the femoralis, not just the jugularis. The steerable mechanisms employed are basic that can be shared with different concepts for fastener 20 and corresponding element 300 and even wire elements 180. A further advantage is that the axial rotation for anchoring or de-anchoring the helix of the medical implant 10 is housed in the center of the steerable catheter 100, so that it is not necessary to rotate the whole handle of the catheter 100.
In particular,
The two-lobe configurations present larger radii of curvature to the patient anatomy than the football design. Via the blossomed tips 40 of the lobe features on the two-lobe configuration, both single lobe and hole “hitch” recapture are facilitated because cinching of the implant/explant wire loop does not cause the fastener 20 to slip out of the tooling.
The V-shaped, protected undercut 26 of the hook ensures alignment with the longitudinal axis of the implant/explant catheter to minimize concerns for unintended binding when transitioning implants 10 form tether- to primary-mode engagements. The undercut 26 at the post 24 provides an easier re-engagement with the implant/explant recapture wire loop from all sides of the fastener 20. As a result, recapture is virtually independent from the relative rotational orientation of the medical implant 10 and the catheter.
The top down footprint of the hook configuration is similar to the two-lobe configuration described above which enables primary engagement with the catheter with the same design of the corresponding coupling element on the catheter side.
The fasteners 20 described provide large translational and/or rotational degrees of freedom when paired with the implant/explant catheter using less complexity and only few discrete components. The mechanical rigidity and lobe-dependent or undercut-dependent topologies offer a means for translating torque which supports the inclusion of helix-based myocardial interfacing strategies of medical implants 10. The reduced complexity and component count additionally offer fewer opportunities for implant “hitch” failure, improving safety/reliability without compromising core functional capabilities.
Post 24 and cross piece 30 may be manufactured of cut wire and the tips of the cross piece 30 rounded. The divot 32 may be cut either before or after assembly.
In an alternative embodiment, post 24 and cross piece 30 may be manufactured as a single assembly and then weld attached to the medical implant 10.
In a further alternative embodiment, implant 10 and fastener 20 may be manufactured as a single assembly, built as a single, monolithic piece of hardware. No weld seams are necessary at all.
In a further alternative embodiment, post 24 may be integrated in the medical implant 10 and the cross piece 30 weld attached to the post 24.
It should be mentioned that, although this embodiment is illustrated only with a two-lobe configuration, the features described therein are applicable to a three-lobe and four-lobe configuration as well.
In step S100, access is obtained to a patient vasculature for a medical implant 10, in particular a leadless pacemaker, which is advanced via an implant/explant catheter. In step S102, the medical implant is routed to the heart and installed. In step S104, the operation of the medical implant and the patient interfacing are assessed in a tether mode of operation. In step S106, the medical implant is released from the implant/explant catheter. Subsequently, in step 107, it is assessed whether a problem exists with the medical implant. If subsequently something problematic is noticed in a monitoring test, such as, for example, a fluoro imaging, the medical implant is recaptured in step S108 with the implant/explant catheter. Depending on the assessment of the detected problem, the medical implant may either be re-installed elsewhere in step S110, or may be explanted in step S112.
Favorably, there are only few steps necessary for removing or reinstalling the medical implant. In particular, the medical implant is a helix-based or side hook based implant to anchor.
In step S200, access is obtained to a patient vasculature where a medical implant, in particular a leadless pacemaker, had been implanted previously. In step S202, the catheter is routed to the medical implant. In step S204, an un-cinched wire loop (or another retrieval tool described above) is placed over a fastener of the medical implant and a tether mode of engagement is subsequently established by cinching the wire loop in step S206, thus securing the capture of the medical implant at the catheter's distal end. By either advancing the catheter and/or tensioning the wire loop and its cinching feature in coordinated fashion, the system transitions from a tethered mode of implant interfacing to one where a lock and key primary engagement is re-established in step S208. In S210, the tooling can translate torque to the medical implant to explant it. The tip of the torque transmitting sheath preferably provides features that guide the fastener of the medical implant into the primary engagement with the coupling element in step S212 and removing the medical implant.
In one embodiment, the catheter 100 comprises a steerable outer sheath 200, surrounding a steerable inner sheath 210 that surrounds a torque transmitting sheath 220 which encloses a cinching sheath 230. Inside the cinching sheath 230, a wire element 180 is arranged with a wire loop 190 at its free end. Preferably, the outer sheath 200 and the inner sheath 210 are equipped with soft tips. The torque transmitting sheath 220 has lock and key features 222 as the coupling element at its distal end, which are intended to accommodate the fastener of the medical implant and to deliver torque thereto. Having a steerable outer sheath 200 and a separate steerable inner sheath 210 enables steering of the device in two planes, and it allows the two steering points to be moved with respect to each other, which is particularly favorable for femoral routing of the catheter 100.
It is to be understood, however, that in some embodiments the outer sheath 200 and cinching sheath 230 may be eliminated and thus support implantation and acute explantation needs with still less complex hardware.
As shown in a simplified way in
In a next step of the implantation procedure, a tethered mode of operation is used, which is shown in
By retracting the wire loop cinching feature alone, the wire loop opens to enable a complete decoupling of the medical implant 10 from the catheter-based tooling (wire loop 190), as shown in
For recapture, as indicated in
The tip of the torque transmitting sheath 220 preferably provides features that guide the fastener 20 of the medical implant 10 into the primary engagement with the coupling element 300. This guide helps to align the implant 10 to the catheter 100 (explant tool) both longitudinally and rotationally. To help align the implant 10 to the catheter 100 (explant tool) longitudinally, in one embodiment, the lock and key mechanism is fluted, to help allow engagement of the fastener 20 at a broad range of angles, and then force alignment as the tow are pulled together.
Favorably, this full suite of articulations has been incorporated into a single tool providing a consolidated design strategy.
The present invention merges a suite of articulations and implant/explant support needs into a common framework, demonstrating a single-tool embodiment. By leveraging a wire-loop-based strategy to retain the medical implant 10 within a keyed interface inside the catheter 100, the present invention supports primary engagement modes. That same wire loop 190, when paired with a cinching feature 230, additionally enables both tether modes as well as recapture of the medical implant 10, thus merging capabilities that are either assigned to a separate tool or left unsupported in designs known in the art.
Although the example presented in the Figures assumes a cylindrical medical implant 10 with a screw-in helix fixation mechanism, the implant-catheter interface can be applied to other configurations as well.
At the proximal end 12 of the medical implant 10, the interface includes one or more fasteners 20 such as closed arcs (e.g., handles, loops) or fasteners as described in the previous Figures. On the catheter side, a hook will extend from the catheter to link into the arc at the proximal end of the medical implant 10 (not shown).
Several thin, flexible, radio-opaque, rabbit-ear loops 18 or snares sprout from the center of the medical implant 10, protruding axially toward the endocardium, and then curving radially away from the axis of the medical implant 10. The degree to which the flexible loops 18 protrude from the proximal end 12 greatly increases the ease of capturing them with the catheter. Although the loops 18 may be relatively large, their thin, flexible construction will minimize hemodynamic interference and potential damage to nearby tissue. Their flexibility will also limit the encapsulation response of the host tissue. The set of loop leaflets will be formed by collapsing one continuous circular wire at several points into a shared housing on the proximal end 12 of the medical implant 10, such that pulling on one loop shortens the rest, similar to a snare (see
A curved, rigid fastener 20, such as a handle, extends from the implant proximal end 12 (see
This interface advantageously addresses concerns associated with the implantation, repositioning, and extraction of grown-in intracardiac leadless pacemakers. Implementing a hook mechanism on the catheter, rather than on the medical implant 10 itself, minimizes the chance for the leadless pacemaker tail to become entangled with the internal structures of the heart. The smooth, curved geometry of the arc(s) on the proximal end 12 of the medical implant 10 also minimizes chronic damage and scarring of the valves and heart wall.
It will be apparent to those skilled in the art that numerous modifications and variations of the described examples and embodiments are possible in light of the above teachings of the disclosure. The disclosed examples and embodiments are presented for purposes of illustration only. Other alternate embodiments may include some or all of the features disclosed herein. Therefore, it is the intent to cover all such modifications and alternate embodiments as may come within the true scope of this invention, which is to be given the full breadth thereof. Additionally, the disclosure of a range of values is a disclosure of every numerical value within that range.
This patent application claims the benefit of co-pending U.S. Provisional Patent Application No. 62/106,721, filed on Jan. 23, 2015, which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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62106721 | Jan 2015 | US |