Recapture Assembly for a Catheter System, Catheter System and Method for Retrieval of an Implant

Abstract

A catheter system and a recapture assembly for the catheter system which serves to expand the system's functionality to support highly-articulated implant recapture. The recapture assembly comprises: a cinch tube with a centering device provided at the distal end of the cinch tube and a tether located within the cinch tube adapted to be telescoped relative to the cinch tube. Also, a method for retrieval of the implant comprising a hitch-like element at its proximal end by the catheter system is disclosed.

Claims

1. A recapture assembly for a catheter system comprising: a cinch tube with a centering device provided at the distal end of the cinch tube, and a tether located within the cinch tube and adapted to be telescoped relative to the cinch tube.

2. The recapture assembly according to claim 1, wherein the centering device is adapted to be activated by moving the cinch tube and/or the tether and/or a pulling element.

3. The recapture assembly according to claim 1, wherein the tether can be configured as a snare.

4. The recapture assembly according to claim 1, wherein the centering device comprises a plurality of radial arms extending from the outside of a distal end of the cinch tube, wherein each radial arm is flexible.

5. The recapture assembly according to claim 4, wherein each radial arm is flexible between a first state in which the radial arm is at least partially deflected in a direction aligned with the outer surface of the cinch tube or at least partially aligned parallel to the outer surface of the cinch tube and a second state in which the radial arm protrudes at a pre-defined angle from the outer surface of the cinch tube.

6. The recapture assembly according to claim 1, wherein the centering device comprises a plurality of wires each wire having a first end and a second end, wherein the first end of each wire is fixedly attached to the distal end of the cinch tube or a fixed ring accommodated at the outer surface of the cinch tube and the second end of each wire is slidably arranged on the outer surface of the cinch tube, wherein the second end is slidably arranged on the cinch tube between a first, most proximal position and a second, more distal position, and wherein in the first position each wire deflects at least partially against the outer surface of the cinch tube and in the second position each wire deflects radially outwards and thereby forming a knee, that protrudes radially outwards from the cinch tube.

7. The recapture assembly according to claim 6, wherein the second end of each wire is attached to a ring accommodated on the outer surface of the cinch tube, wherein the ring is slidable arranged on the cinch tube between the first, most proximal position and the second, more distal position.

8. The recapture assembly according to claim 1, wherein the centering device comprises a distal section of the cinch tube having a plurality of bands separated by a plurality of through-going slits, both running parallel to the longitudinal axis of the cinch tube, wherein the plurality of bands of the distal section is deflectable radially outwards and thereby forming at least one knee that protrudes radially outwards from the cinch tube.

9. The recapture assembly according to claim 1, wherein the cinch tube is configured to be steerable.

10. A catheter system comprising at least one outer sheath and the recapture assembly of claim 1 as a modular insert adapted to be passed through the outer sheath.

11. The catheter system of claim 10, wherein the recapture assembly is adapted to telescope from the distal end of the outer sheath.

12. The catheter system of claim 10, wherein an inner diameter of a distal section of the outer sheath is greater than an inner diameter of another section accommodated proximally to the distal section of the outer sheath.

13. A method for retrieval of an implant comprising a hitch-like element at its proximal end by the catheter system of claim 10, wherein the method comprises the following steps: pairing the recapture assembly with the catheter system, if applicable, introducing the catheter system into the patient's body and moving a distal end of the catheter system within the vasculature of the patient until it is in close proximity to the implant to be explanted, telescoping the tether and the cinch tube from the distal end of the outer sheath, telescoping the tether from the distal end of the cinch tube and capturing the hitch-like element at the implant, and retracting the tether with the implant into proximal direction, whereby the centering device of the cinch tube is activated during at least one of the steps of this bullet point, and retracting the cinch tube into or within the outer sheath of the catheter system.

14. The method of claim 13, wherein the centering device of the cinch tube is activated. by telescoping the cinch tube with regard the outer sheath of the catheter system thereby transferring the plurality of radial arms from the first state into the second state, and/or by moving a ring connected with the wires from the first, most proximal position to the second, more distal position, and/or by retracting the tether with the implant into proximal direction such that the proximal end of the implant acting on the distal end of the cinch tube thereby folding the plurality of bands of the distal section of the cinch tube radially outwards and thereby forming at least one knee that protrudes radially outwards from the cinch tube.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The specification refers to the accompanying Figures showing schematically:

[0046] FIG. 1 a longitudinal section of the distal end of an embodiment of a catheter system with an implantation assembly as a modular insert in a first step during implantation of a leadless cardiac pacemaker,

[0047] FIG. 2 the elements of FIG. 1 in a second step during implantation,

[0048] FIG. 3 the elements of FIG. 1 in a third step during implantation,

[0049] FIG. 4 a longitudinal section of the distal end of the catheter system of FIG. 1 with a first embodiment of a recapture assembly as modular insert in a first step during retrieval of a leadless cardiac pacemaker,

[0050] FIGS. 5A-5E the elements of FIG. 4 in further steps during retrieval,

[0051] FIG. 6 the elements of FIG. 4 in a another step during retrieval,

[0052] FIG. 7 the elements of FIG. 4 in yet a another step during retrieval,

[0053] FIGS. 8A-8B the distal end of the catheter system of FIG. 1 with a second embodiment of a recapture assembly as a modular insert in: FIG. 8A a longitudinal section, and FIG. 8B a top view (recapture assembly only without snare), both in a first step during retrieval of a leadless cardiac pacemaker,

[0054] FIGS. 9A-9B the elements of FIG. 8 in: FIG. 9A a longitudinal section, and FIG. 9B a top view (recapture assembly only without snare), both in a second step during retrieval of the leadless cardiac pacemaker,

[0055] FIGS. 10A-10B the distal end of the catheter system of FIG. 1 with a third embodiment of a recapture assembly as a modular insert in: FIG. 10A a longitudinal section, and FIG. 10B a top view (recapture assembly only without snare) in the first step (analogous to FIG. 4) during retrieval of a leadless cardiac pacemaker,

[0056] FIGS. 11A-11B the elements and view of FIG. 10 in: FIG. 11A a longitudinal section, and FIG. 11B a top view (recapture assembly only without snare), both in a second step during retrieval of the leadless cardiac pacemaker,

[0057] FIG. 12 a fourth embodiment of an recapture assembly with a leadless cardiac pacemaker in a side view, in a first step during retrieval of a leadless cardiac pacemaker, and

[0058] FIG. 13 the elements of FIG. 12 in a second step during retrieval of the leadless cardiac pacemaker.

DETAILED DESCRIPTION

[0059] By using FIGS. 1 to 3, an embodiment of a catheter system is described which does not only comprise a recapture assembly as indicated with regard to the other Fig. below but additionally comprises an implantation assembly. FIGS. 1 to 3 depict the catheter system during implantation of an implant, for example a leadless cardiac pacemaker 1 (the figures show only a proximal end of the leadless cardiac pacemaker 1). The catheter system comprises an outer sheath in form of a tube 10 which comprises at its distal end a section 10a with an enlarged inner diameter (see FIG. 3). Accordingly, the section 10b proximal to the section 10a has a smaller inner diameter. The outer tube 10 covers an implantation assembly as a modular insert of which one embodiment is shown in FIGS. 1 to 3. The implantation assembly comprises a push tube 20 and a suture-like loop 22. The suture-like loop 22 is accommodated within the push tube 20, whereas the push tube 20 may mechanically translate/telescope relative to the outer sheath 10 of the catheter system. The suture-like loop 22 runs through a hitch of the cardiac pacemaker 1, wherein the hitch is provided at the proximal end of the cardiac pacemaker 1. The cardiac pacemaker 1 is transported with the catheter system to the implantation site, for example within a heart's ventricle. Subsequently, after introducing the pacemaker 1 into the heart tissue, the suture-like loop 22 releases the cardiac pacemaker 1 (see FIG. 1) after a cutter of the catheter system (not shown) had cut through one end of the suture-like loop 22 and removes the cardiac pacemaker 1 from the catheter system (see FIG. 2). After this, the push tube 20 and the suture-like loop 22 are removed from the outer sheath 10. This is shown in FIG. 3.

[0060] Accordingly, the push tube 20 is used to deploy the cardiac pacemaker 1 and facilitates anchoring engagement with the patient's myocardium. Following fixation of the cardiac pacemaker 1 within the heart, the push tube 20 can be retracted to allow the cardiac pacemaker 1 to maintain only a tethered connection to the catheter system by means of the compliant suture-like loop 22. The highly compliant suture-like loop 22 allows the cardiac pacemaker 1 to follow the free motion of the heart wall and to respond to hemodynamic forces without fully decoupling it from the implantation tooling. Decoupling the cardiac pacemaker 1 from the catheter system involves cutting the suture-like loop 22 and then unthreading it from the catheter system and cardiac pacemaker 1.

[0061] Recapture is then afforded by removing the push tube 20 and subsequently installing the recapture assembly within the catheter system as a modular insert which is shown in FIG. 4. The recapture assembly comprises a steerable cinch tube 30 with a tether in form of a snare 32 accommodated within. The cinch tube 30 according to a first embodiment shown in FIGS. 4 to 7 comprises a plurality of wires 34, for example six wires 34, wherein a first, most distal end of each wire is attached to the distal end of the cinch tube 30 and the second, more proximal end of the wire 34 is attached to a slidable ring 35. The wires 34 are uniformly accommodated around the circumference of the cinch tube 30 and form a centering device. In the first position of the wires 34 shown in FIG. 4 at least a section of each wire 34 lies against the outer surface of the cinch tube 30.

[0062] To install the recapture assembly within the catheter system, the cinch tube 30 as well as the snare 32 are passed through the HCP-facing terminus of the catheter system distally towards the in-body cardiac pacemaker 1. During this process, the wires 34 reside in a non-deployed condition (or are compressed into a compliant condition capable of passing through the inner lumen of the baseline implantation tool) allowing ease of passage through the narrow inner lumen 10b of the outer tube 10.

[0063] In the next step, which is shown in FIGS. 5A-5E and 6 the cinch tube 30 end the snare 32 are moved out of the distal end of the outer sheath 10 towards the cardiac pacemaker 1. In FIG. 5A, the cinch tube 30 is moved distally until it reaches out of the outer sheath 10. The wires 34 are expanded in order to form the centering device (FIG. 5B). The recapture snare 32 is moved out of the cinch tube 30 (FIG. 5C). In FIG. 5D, the recapture snare 32 reaches the implant and wraps around the T-shaped hitch of the cardiac pacemaker 1. The recapture snare 32 is pulled until the proximal end of the cardiac pacemaker 1 (e.g. the T-shaped hitch) is in direct contact with the distal end of the cinch tube 30 (FIG. 5E). The steerable, telescoping cinch tube 30 can be exercised to navigate to the implant in form of the cardiac pacemaker 1 and establish a tethered connection with the snare 32. Prior to, or in concert with, or following the tightening of the recapture snare 32 using the steerable, telescoping cinch tube 30 the distal terminus of the cinch tube 30 deploys its centering device (wires 34). For example, as shown in FIG. 6 the slidable ring 35 is shifted into distal direction relative to the cinch tube 30, for example by pulling a (not shown) wire connected to the slidable ring 35 or the cinch tube 30. Thereby each wire 34 is folded forming at least one knee that protrudes outwards from the cinch tube. By the centering device the recapture assembly with the cardiac pacemaker 1 is centered within the outer sheath 10 and the cardiac pacemaker 1 safely enters the outer sheath 10 and aligns with regard to the outer sheath 10 for back transport through the catheter (see FIGS. 6 and 7).

[0064] FIGS. 8 and 9 show another embodiment of a recapture assembly with a different, less complex centering device. In this embodiment, the centering device comprises a plurality of radial arms (spokes) 37 which are attached with its first end to the outer surface of the cinch tube 30 (for example by a ring or hub 31, in which the individual radial arms 37 fit). In a first position shown in FIG. 8, the radial arms 37 at least partially lie against the outer surface of the cinch tube 30 or run at least partly parallel to the outer surface of the cinch tube 30 and/or its longitudinal direction. In a second step, when the cinch tube 30 is moved into the enlarged section 10a of the outer tube 10 and out of the distal end of the outer tube 10 the biased radial arms 37 flex outwards in order to provide alignment of the cinch tube with the recaptured cardiac pacemaker because, for example, the radial arms 37 have a respective shape-memory configuration. The angle a between the radial arm 37 and a tangent to the outer surface of the cinch tube 30 at the attachment point of the radial arm 37 (see FIG. 9A), wherein the tangent is parallel to the longitudinal axis of the cinch tube 30) may be between 60 and 150, for example about 90.

[0065] The third embodiment shown in FIGS. 10 and 11 is similar to the embodiment shown in FIGS. 4 to 7 with regard to the configuration of the cinch tube 30 and the wires 34. However, the activation of the centering device in this embodiment occurs when the cinch tube 30 is slid from a first position within the outer tube section with the smaller diameter 10b (see FIG. 10) with regard to the outer tube 10 such that the wires 34 are located within the enlarged distal section 10a of the outer tube 10 or distally from the distal end of the outer tube 10. The wires are biased or are provided with a shape-memory configuration such that they auto-deploy as soon as they reach the enlarged diameter section 10a of the outer tube 10 and/or pass the distal end of the outer tube 10. The deployment of the wires 34 is provided by offering a larger, non-compressing inner diameter by the outer sheath 10 (see FIG. 11). The recapture of the implant 1 may be performed similar to the first embodiment shown in FIGS. 4 to 7.

[0066] A fourth embodiment of a recapture assembly is shown in FIGS. 12 and 13. In this embodiment, a cinch tube 40 comprises a plurality of through-going slits 38 running parallel to the longitudinal axis of the cinch tube 40. The distal end of each slit 38 has a certain distance from the distal rim of the cinch tube 40. FIG. 12 shows a first position which is taken by the cinch tube 40 during installing the recapture assembly within the catheter system. During retrieval of the cardiac pacemaker 1, when the pacemaker 1 is pulled by the snare 32 toward the catheter system, the hitch-like end of the cardiac pacemaker abuts to and presses against the distal end of the cinch tube 40. By this force along the proximal direction the bands 40a separated by the slits 38 of the distal section of the cinch tube 40 are bent or folded forming at least one knee that radially protrudes outwards from the cinch tube 40 forming a centering device (see FIG. 13).

[0067] The catheter system, the recapture assembly and the method ease surgical implantation and extraction by shortening the otherwise necessary rigid in-catheter length by eliminating the presence of an alignment cup during implantation procedures, easing implantation procedures and avoiding unwanted additional pressure on device length reduction. The recapture assembly in its modular structure further avoids delivery tooling complexity and reduces intraoperative risk of user error by avoiding interaction with the steering functionalities native to the implantation tool (implantation assembly) and by presenting the retrieval controls only when retrieval is required. The system also reduces costs by separating retrieval assembly complexities from the implantation assembly.

[0068] 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, including the end points.

REFERENCE NUMBERS

[0069] 1 leadless cardiac pacemaker [0070] 10 outer tube [0071] 10a distal section of outer tube 10 [0072] 10b another section proximal to distal section 10a of outer tube 10 [0073] 20 push tube [0074] 22 suture-like loop [0075] 30, 40 cinch tube [0076] 31 ring [0077] 32 snare [0078] 34 wire [0079] 35 slidable ring [0080] 37 radial arm [0081] 38 through-going slit [0082] 40a band [0083] angle