CN217548130U - Engagement assemblies, core assemblies, and systems for delivering implants - Google Patents

Abstract

The utility model discloses an engagement assembly, core subassembly and system for delivering implant, this engagement assembly can carry out centre gripping and release to the implant, and this engagement assembly includes: a pin element including a pin head having a diameter that decreases from a distal end to a proximal end; and a proximal pusher comprising a cavity for receiving the pin head, a surface of the cavity being in clearance fit with a surface of the pin head; the near end of the near end pusher is provided with an opening; wherein the proximal end of the pin element is fixedly connected to the distal end of the first elongate delivery member in the catheter via the aperture and the proximal end of the proximal pusher is fixedly connected to the distal end of the second elongate delivery member in the catheter; the pin head is movable relative to the proximal pusher along the longitudinal axis of the catheter by relative movement between the first elongate delivery member and the second elongate delivery member. The core assembly and system include the joint assembly. The utility model discloses can retrieve and reposition the implant after the release, and can effectively prevent to slide between implant and the joint Assembly.

Description

Engagement assemblies, core assemblies, and systems for delivering implants

Technical Field

The present invention relates to engagement assemblies, core assemblies, systems, and methods for delivering implants.

Background

Minimally invasive interventions are a treatment for vascular aneurysms, and typically involve the delivery of vascular implants, such as but not limited to stents, coils, aneurysm occlusion devices, to the site of a lesion by a delivery system. The delivery system generally includes a catheter for insertion into a blood vessel to receive a vascular implant and to guide the vascular implant to a lesion in the blood vessel; the guidewire is typically fixedly connected to a portion of the implant engaging assembly; the implant engagement assembly is typically in contact with the implant for delivering the implant along the catheter to the site of the lesion under the influence of the guidewire.

However, the implant is not always deployed in the precise location that a physician or operator may want, and therefore may need to be retracted into the catheter prior to full deployment. In conventional delivery systems, the implant is typically released immediately after being pushed out of the distal end of the catheter, and cannot be retrieved into the delivery tube for release. In this case, even if the release position of the implant is incorrect, adjustment cannot be made. This can cause adverse complications to the procedure, increasing the risk of the procedure.

To this end, it is desirable to design a delivery system that can be retrieved back into the delivery catheter for re-release after the implant is released.

Currently, patent CN112716667A is known to disclose an endovascular implant fixation retention structure and an endovascular implant delivery system, comprising: the catheter includes a delivery tube, a guide wire extending through the delivery tube, and a holder connected to the guide wire. In the initial stage of delivery, the guide wire and the delivery pipe are kept relatively fixed, and the support is positioned at the head of the delivery pipe and plays a role in fixing the implant; in the later period of delivery, the guide wire and the delivery pipe move relatively, the support extends out of the head of the delivery pipe, and the implant is released. When the length of the implant extending out of the far end of the conveying pipe does not exceed a certain value, the implant can be recovered to the position in the conveying pipe through the guide wire and released again.

However, patent CN112716667A has the following problems:

on one hand, the implant is driven to slide along the delivery pipe by the friction force between the implant and the support, and the bending change of the vessel shape can cause the change of the friction force between the implant and the support and the influence of the flatness of the inner wall of the conduit, the implant and the support can slide relatively, even the implant can fall off from the support, and therefore the delivery of the implant in the delivery pipe can be influenced.

On the other hand, the relative positions of the implant and the support during assembly are uncertain, and the uncertainty of the relative positions of the implant and the support is aggravated by the relative sliding which may occur during the delivery process, so that the release position of the implant may be inaccurate, and the position of the implant needs to be adjusted for many times, which may cause the problems of reduction of the release efficiency of the stent, increase of the operation duration, increase of the operation risk and the like.

SUMMERY OF THE UTILITY MODEL

It is an object of the present invention to provide an engagement assembly for delivering an implant that, while ensuring delivery of the implant to the site of the lesion, also enables recovery of the implant after release, allowing the implant to be repositioned as desired.

It is another object of the present invention to provide a core assembly for delivering an implant.

It is another object of the present invention to provide a system for delivering an implant.

It is yet another object of the present invention to provide a method for delivering an implant.

According to a first aspect of the present invention, a coupling assembly for delivering an implant is disclosed, adapted to clamp and release the implant when the implant is delivered via a catheter. The joint assembly includes: a pin element including a pin head having a diameter that decreases from a distal end to a proximal end; a proximal pusher comprising a cavity adapted to receive the pin head, a surface of the cavity being a clearance fit with a surface of the pin head; the near end of the near end pusher is provided with an opening; wherein the proximal end of the pin element is fixedly connected with the distal end of the first elongated delivery member in the catheter via the opening, and the proximal end of the proximal pusher is fixedly connected with the distal end of the second elongated delivery member in the catheter; wherein the pin head is movable relative to the proximal pusher along the longitudinal axis of the catheter by relative movement between the first and second elongated delivery members to move the pin head into or out of the lumen of the proximal pusher.

Preferably, the engagement assembly includes a clamped state in which the pin head is located within the chamber of the proximal pusher and the gap between the surface of the pin head and the surface of the chamber is no greater than the thickness of the implant to enable the proximal end of the implant to be clamped between the pin head and the chamber of the proximal pusher.

Preferably, the engagement assembly includes a release condition in which a clearance between a surface of the pin head and a surface of the cavity is greater than a thickness of the implant to enable the implant to be released from the engagement assembly.

Further, the diameter of the pin head decreases linearly from the distal end to the proximal end; or the diameter of the pin head decreases nonlinearly from the distal end to the proximal end; or the diameter of the pin head decreases piecewise linearly from the distal end to the proximal end.

Preferably, the pin head is a tapered or frusto-tapered pin head.

Preferably, the conical surface of the conical or frusto-conical pin head is at an angle of no more than 30 degrees, more preferably no more than 20 degrees, to the central axis.

Preferably, in the clamped state, the length of the proximal end of the implant clamped between the pin head and the chamber of the proximal pusher represents between 5% and 30% of the total length of the implant.

Preferably, the first elongate delivery element is a guide wire and the second elongate delivery element is a tubular member fitted over the guide wire.

Preferably, the tubular member is a hypotube.

Preferably, the proximal end of the pin element is fixedly connected to the first elongate delivery member by welding, adhesive bonding, hinging and/or clipping, and the proximal end of the proximal pusher is fixedly connected to the second elongate delivery member by welding, adhesive bonding, hinging and/or clipping.

Preferably, the pin element further comprises a pin shank connected to the pin head, the pin head being fixedly connected to the first elongate delivery member via the pin shank; the opening is in clearance fit with the pin shank. Preferably, the pin head and the pin shank are integrally formed.

Preferably, the proximal pusher has a cylindrical outer surface; the diameter of the distal-most end of the pin head is less than the diameter of the cylindrical outer surface of the proximal pusher.

Preferably, the diameter of the bore is less than the diameter of the proximal-most end of the pin head.

According to a second aspect of the present invention, there is provided a core assembly for delivering an implant. The core assembly comprises an engagement assembly for delivering an implant according to the first aspect of the invention, further comprising: a first elongated delivery member and a second elongated delivery member positioned in the catheter.

According to a third aspect of the present invention, a system for delivering an implant is disclosed. The system comprises a core assembly for delivering an implant according to the second aspect of the invention, further comprising a catheter and an implant.

According to a fourth aspect of the present invention, a method for delivering an implant is disclosed. The method uses an engagement assembly for delivering an implant according to a first aspect of the invention, the method comprising: pushing the first and second elongate delivery members while pulling the first elongate delivery member back relative to the second elongate delivery member to deliver the engagement assembly and implant to a designated location of the hollow anatomical structure within the catheter and to clamp the proximal end of the implant between the pin head and the chamber of the proximal pusher; after the implant reaches the designated position, pulling the catheter proximally, extending the engagement assembly and the implant out of the catheter; pushing the first elongated delivery member to move the pin head away from the pusher chamber and determining whether an adjustment to the position of the implant is required: if the position of the implant needs to be adjusted, retracting the first elongate delivery member to re-enter the pin head into the chamber of the proximal pusher to cause the engagement assembly to re-grip the implant; if the position of the implant does not need to be adjusted, the first and second elongate delivery members are pulled back to release the implant and withdraw the engagement assembly.

Compared with the prior art, the utility model has the advantages of it is following:

1. while ensuring delivery of the implant to the site of the lesion, the implant can also be retrieved after release, allowing the implant to be repositioned as desired.

2. The pin head with the diameter gradually reduced from the far end to the near end and the chamber of the near-end pusher can ensure large pushing force and clamping force, and prevent the implant from accidentally breaking loose and falling off. This is because, on the one hand, during the delivery of the implant, the chamber surface of the proximal pusher actually acts against the engagement portion of the implant, generating a forward thrust on the engagement portion of the implant, which is more robust and reliable than the thrust generated by friction alone; on the other hand, the pin head with the diameter gradually reduced from the far end to the near end can increase the contact area with the implant relative to the cylindrical pin head under the condition of the same length, and the clamping force is increased along with the increase of the pulling-back force of the pin head, so that the clamping force of the implant can be effectively ensured and regulated.

3. Due to the abutting action and the large clamping force of the engagement assembly on the implant, the implant can be effectively prevented from slipping with a delivery device (such as a bracket engagement assembly and the like) during the delivery process, the implant cut-off point is fixed, and therefore the implant can be delivered to the lesion position more accurately in the process of observing the positioning of the implant by means of development and combining the delivery operation to place the implant, the number of times of adjusting the position of the implant is reduced, and the operation time is saved.

Drawings

The accompanying drawings illustrate, by way of example and not by way of limitation, embodiments of the present invention, in which:

fig. 1 shows a schematic structural view of a conveying system according to an embodiment of the present invention;

fig. 2 illustrates a schematic view of the distal end of the pin element being disengaged from the proximal pusher in preparation for releasing the stent in a delivery system according to one embodiment of the present invention;

fig. 3 shows a schematic view of a stent being completely released in a delivery system according to an embodiment of the present invention.

Detailed Description

The technical solution of the present invention will be described in further detail below with reference to the following embodiments, but the present invention is not limited to the following embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the embodiments described herein, the preferred methods, devices, and materials are described herein.

The terms "distal", "distal" or "proximal", "proximal" in the following description refer to a position or direction relative to the operator. "distal" or "distal" refers to a location or direction away from the operator.

The terms "connected," "connected," or "fixedly connected" refer to a connection relationship between two elements, which includes not only the case where two elements are directly connected or in contact, but also the case where two elements are connected through one or more intermediate elements, and the case where two elements are integrally formed. Further, the term "fixedly attached" refers to a connection in which there is little relative movement between two elements after the two elements are secured, including both releasable and non-releasable connections.

Fig. 1 shows a schematic structural view of a conveying system 10 according to an embodiment of the present invention.

According to this embodiment, the delivery system of the present invention can be used to deliver and/or deploy an implant (e.g., a stent) into a hollow anatomical structure, such as a blood vessel. As shown in fig. 1, the delivery system of the present invention includes a stent 11, a core assembly, and a catheter 13.

The stent 11 may comprise a braided stent or other form of stent, such as a laser cut stent, a rolled stent, or the like. In embodiments related to braided stents, the stent 11 may be braided from round or oval filaments. Further, the stent 11 is self-expanding and one or more filaments may be formed of a biocompatible metallic material or a biocompatible polymer.

The conduit 13 is located externally of the core assembly, within which the core assembly is relatively slidable, and which may be configured to carry the stent through the conduit. Once the distal end of the catheter 13 is at the desired location, the stent 11 may be pushed out of the catheter 13 by withdrawing the catheter 13, or the stent 11 may be pushed out of the catheter 13 by pushing the core assembly. The catheter 13 is an elongated structure and comprises a proximal end, a distal end and a central cavity, wherein the distal end of the catheter 13 is provided with an opening, so that the core assembly carrying the stent 11 extends out of the catheter 13 from the opening to release the stent 11. The catheter 13 may be a microcatheter or a sheath.

The core assembly is located within the central chamber of said duct 13 and is axially movable as a whole with respect to the duct 13. The core assembly may be advanced within the lumen of catheter 13 (or catheter 13 may be retracted) to expose stent 11 and allow it to expand within the patient's vessel. The core assembly includes, among other things, an engagement assembly, a second elongated delivery member 15, and a first elongated delivery member. An engagement assembly is located at the distal ends of the first and second elongated delivery members and the proximal end of the stent 11 engages the engagement assembly to allow the user to push the crimped stent 11 forward out of the catheter 13.

The engagement assembly further comprises a pin element 41 and a proximal pusher 42.

The pin member 41 may include a connected pin head 43 and pin shank 44, wherein the pin head 43 and pin shank 44 are located at the distal and proximal ends of the pin member 41, respectively. The pin shaft 44 is rod-shaped, rod-shaped or flat bar-shaped, and the pin head 43 is a structure with a diameter gradually decreasing from the distal end to the proximal end, and the diameter of the pin head 43 gradually decreases from the distal end to the proximal end in a linear or non-linear way. When this reduction is a linear reduction, the configuration of the pin head 43 is a tapered configuration or a frustoconical configuration. When this reduction is a non-linear reduction, the configuration of the pin head 43 is a generally conical configuration or other suitable configuration, such as a gyroscope, horn, bell, or the like. Furthermore, the reduction may also be a piecewise linear reduction. For example, the pin head 43 may include a distal section and a proximal section, wherein the distal and proximal sections are frustoconical structures having different apex angles.

In particular, when the pin head 43 is a tapered or frusto-tapered pin head, the conical surface of the tapered or frusto-tapered pin head is at an angle of no more than 30 degrees, preferably no more than 20 degrees, to the central axis. Such an angle may allow the stent 11 to be more securely and stably clamped between the pin head 43 and the proximal pusher 42 without easily deforming the stent 11.

In the preferred embodiment, the pin head 43 and the pin shank 44 are integrally formed. In some embodiments, the pin head 43 and the pin shank 44 may also be formed separately and fixedly attached by welding, adhesive, hinging, and/or snapping.

In the preferred embodiment, the outer surface of the proximal pusher 42 is cylindrical and includes an open cavity, which cavity of the proximal pusher 42 is adapted to receive the pin head 43 of the pin member 41. This cavity is a clearance fit with the pin head 43 of the pin element 41. In other words, the diameter of the lumen of the proximal pusher 42 also tapers distally to proximally. The proximal end of the proximal pusher 42 is apertured to mate with the pin shank 44 of the pin member 41. The term "match" herein means that the pin shank 44 is sized substantially equivalent to the aperture such that the pin shank 44 can pass through the aperture. Also, the cross-sectional shape of the pin shank 44 may or may not conform to the shape of the opening, so long as it is ensured that the pin shank 44 can pass through the opening. The aperture is preferably located at the proximal center of the proximal pusher 42.

The engagement assembly includes a clamped state and a released state. In the clamped state the pin head 43 of the engagement assembly is located in the cavity of the proximal pusher 42 and there is a gap 45 between the surface of the pin head 43 of the pin element 41 and the surface of the cavity of the proximal pusher 42, said gap 45 being adapted to receive the proximal end of the stent 11, the thickness of the gap 45 being no greater than the thickness of said stent, which ensures a firm grip (firm grip) of the stent, i.e. that the proximal end of the stent 11 can be clamped between the pin head 43 and the cavity of the proximal pusher 42. In the released state, the clearance between the surface of the pin head 43 and the surface of the cavity is greater than the thickness of the bracket 11 to enable the bracket 11 to be released from the engagement assembly. In the released state, the pin head 43 may or may not be completely outside the chamber of the proximal pusher 42.

Furthermore, in the clamped state, the length of the proximal end of the stent 11 clamped between the pin head 43 and the chamber of the proximal pusher 42 preferably amounts to 5-30% of the total stent length. Such a clamping ratio ensures that the stent 11 is more stably and firmly clamped, prevents the stent 11 from falling off or slipping relative to the engagement member during delivery, thereby affecting the accuracy of the stent release position, and does not easily cause deformation of the stent.

The distal end of the first elongate delivery member is fixedly attached to the proximal end of the pin shaft 44 of the pin member 41 via the aperture of the proximal pusher and the distal end of the second elongate delivery member 15 is fixedly attached to the proximal end of the proximal pusher 42. The fixed connection between the first elongate delivery member and the pin shank 44 of the pin element 41 and the fixed connection between the second elongate delivery member 15 and the proximal pusher 42 may be by welding, adhesive, hinging and/or snapping, etc.

It is noted that although in the previous description it was mentioned that the pin element 41 comprises a pin shank 44 and the pin head 43 is connected with the first elongate delivery member by the pin shank 44, in practice the pin element 41 does not necessarily comprise a pin shank 44. For example, in some embodiments, the distal end of the first elongated delivery member can also be fixedly attached directly to the pin head 43 via an opening in the proximal end of the proximal pusher 42, where the opening in the proximal end of the proximal pusher 42 mates with the distal end of the first elongated delivery member. In this case, the distal end of the first elongated delivery member directly provides push-pull control of the pin head 43. Of course, the presence of the pin handle 44 is also advantageous, for example, because the pin member 41 and the elongate delivery member can be securely attached by the pin handle 44 more efficiently and quickly during assembly.

In this embodiment, the first elongate delivery member is a guidewire and the second elongate delivery member 15 is a delivery tube. The delivery pipe is sleeved on the guide wire and can play a certain supporting and protecting role on the guide wire. It is noted that in other embodiments, the first elongate delivery member and the second delivery member may further comprise a guidewire, a delivery tube, a coil, or any combination thereof. The guide wire may be a metal filament made of a metal material, and the specific shape and structure thereof are not described in detail herein. The delivery tube may be a hypotube or other suitable tubular structure.

Further, preferably, the diameter of the distal-most end of the pin head 43 is smaller than the diameter of the cylindrical outer surface of the proximal pusher 42. As such, when the pin head 43 is fully advanced into the chamber of the proximal pusher 42, the distal-most end of the pin head 43 does not extend radially beyond the proximal pusher 42. Preferably, the diameter of the opening is smaller than the diameter of the proximal-most end of the pin head 43 and the diameter of the opening is greater than or equal to the diameter of the pin shaft 44 so that the pin head 43 can be lodged in the lumen of the proximal pusher 42 when the pin shaft 44 is pulled back by the guidewire.

According to the above design, the axial movement of the pin element 41 and the proximal pusher 42 along the catheter 13 can be controlled by controlling the axial movement of the delivery tube and the guide wire along the catheter 13, respectively, to achieve the clamping, delivery, release, re-clamping and re-release of the stent 11.

For example, when the guidewire is pushed forward relative to the delivery tube, the pin element 41 moves forward relative to the proximal pusher 42 to move the pin head 43 of the pin element 41 out of the lumen of the proximal pusher 42 to facilitate release of the proximal end of the stent 11. As another example, when the guidewire is pulled rearwardly relative to the delivery tube, the pin element 41 moves rearwardly relative to the proximal pusher 42, and the pin head 43 of the pin element 41 enters the lumen of the proximal pusher 42 to engage or re-engage the proximal end of the stent 11. As another example, when the pin head 43 of the pin element 41 is fully advanced into the lumen of the proximal pusher 42 and simultaneously pushes the delivery tube and guidewire distally along the catheter 13, the engagement assembly remains engaged with the proximal end of the stent 11 and simultaneously pushes the stent 11 distally.

Meanwhile, according to the above design, since the stent 11 is actually wrapped and held in the chamber of the proximal pusher 42, and the chamber is adapted to the shape of the pin 43, and the diameter of the chamber is gradually reduced from the distal end to the proximal end, the chamber surface of the proximal pusher 42 actually abuts against the engagement portion of the stent 11 during the delivery of the stent 11, thereby pushing the engagement portion of the stent 11 forward. This abutting thrust is completely different from the thrust of the prior art which is generated solely by friction. For the driving force that produces by the friction, the utility model discloses in by leaning on the driving force that the effect produced more firm reliable, can prevent effectively that support 11 from sending the in-process and sending device (for example, support joint subassembly etc.) to take place to slide to make support 11 can deliver to pathological change position more accurately, reduce the number of times of support position adjustment, and then save operation time.

This embodiment discusses the case when the implant is a stent and a delivery system for the stent, however other annular implants are contemplated for delivery by the delivery system, such as microcoils, occluders or similar devices. The stent may include a proximal end and a distal end. The implant may be configured to interfere with blood flow for the purpose of treating an aneurysm, such as an aneurysm in a blood vessel, including an artery in the brain or elsewhere within the body, such as a peripheral artery.

A method for delivering an implant according to one embodiment of the present invention is described below.

FIG. 2 shows a schematic view of the distal end of the pin element 41 disengaged from the proximal pusher; fig. 3 shows a schematic view of the stent being fully released.

As shown in fig. 2 and 3, the method generally includes the steps of:

(1) The engagement assembly and stent 11 are loaded into the catheter 13 and delivered via the catheter 13 to the vicinity of a designated location (i.e., lesion) of the hollow anatomical structure.

In this step, the engagement assembly is held in a clamped state by manipulating the delivery tube and guidewire as the stent 11 is delivered within said catheter 13, the proximal end of the stent 11 being clamped between the pin head and the lumen of the proximal pusher. A particular mode of operation is to simultaneously advance the delivery tube and the guidewire and simultaneously retract the guidewire relative to the delivery tube to maintain the two relatively stationary during delivery, thereby causing the engagement assembly to distally advance the stent 11 to a desired location while gripping the stent 11.

(2) When the stent 11 is delivered to the lesion site, the engagement assembly is placed in a released state by manipulating the delivery tube and the guidewire to prepare for releasing the stent, including first pulling the catheter 13 proximally to extend the engagement assembly out of the catheter 13, thereby exposing most of the stent (i.e., the portion of the stent 11 other than the proximal end); the guide wire is then pushed distally to push the pin shaft 44 of the pin member 41 distally through the guide wire, causing the pin head 43 of the pin member 41 to gradually move out of the lumen of the proximal pusher 42 such that the gap between the surface of the pin head 43 and the surface of the lumen of the proximal pusher 42 is greater than the thickness of the stent 11, such that the proximal end of the stent 11 loses its gripping force and is thus released.

(3) After the pin head 43 exits the chamber of the proximal pusher 42, it can be further determined whether the position of the stent 11 needs to be adjusted. If the position of the stent 11 needs to be adjusted or if the stent needs to be retracted otherwise, the guide wire can be pulled back to pull the pin shaft 44 of the pin member 41 in the proximal direction and again pull the pin head 43 of the pin member 41 into the lumen of the proximal pusher 42, which can place the engagement assembly in a clamped state to Re-clamp the stent 11 for Re-capture and Re-positioning (Re-capture and Re-positioning). If the stent 11 can be released without readjusting the position of the stent 11, the guidewire and the delivery tube are simultaneously pulled back to simultaneously pull the pin elements 41 and the proximal pusher 42 in the proximal direction, the engagement assembly will remain released while the position of the stent 11 is maintained by the friction of the stent 11 with the tissue (e.g., the vessel wall) at the desired location, and the proximal end of the stent 11 is released from the lumen of the proximal pusher 42 by the withdrawal of the proximal pusher 42, thereby completely releasing the stent 11.

The foregoing description, for purpose of explanation, has been referenced to specific embodiments of the invention. However, the illustrative descriptions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed.

Claims (15)

1. A coupling assembly for delivering an implant, adapted to grip and release the implant as it is delivered via a catheter, the coupling assembly comprising:

a pin element including a pin head having a diameter that decreases from a distal end to a proximal end;

a proximal pusher comprising a cavity adapted to receive the pin head, a surface of the cavity being in clearance fit with a surface of the pin head; the near end of the near end pusher is provided with an opening;

wherein the proximal end of the pin element is fixedly connected with the distal end of the first elongated delivery member in the catheter via the opening, and the proximal end of the proximal pusher is fixedly connected with the distal end of the second elongated delivery member in the catheter;

wherein the pin head is movable relative to the proximal pusher along the longitudinal axis of the catheter by relative movement between the first and second elongate delivery members to move the pin head into or out of the lumen of the proximal pusher.

2. The engagement assembly for delivering an implant according to claim 1, wherein the engagement assembly includes a grip state in which the pin head is located within a chamber of a proximal pusher and a gap between a surface of the pin head and a surface of the chamber is no greater than a thickness of the implant to enable a proximal end of the implant to be clamped between the pin head and the chamber of the proximal pusher.

3. The engagement assembly for delivering an implant according to claim 1 or 2, wherein the engagement assembly includes a release state in which a gap between a surface of the pin head and a surface of the cavity is greater than a thickness of the implant to enable the implant to be released from the engagement assembly.

4. The engagement assembly for delivering an implant of claim 2, wherein in the clamped state, a length of the proximal end of the implant captured between the pin head and the chamber of the proximal pusher is between 5% and 30% of an overall length of the implant.

5. The engagement assembly for delivering an implant according to claim 1, wherein the diameter of the pin head decreases linearly from the distal end to the proximal end; or the diameter of the pin head decreases nonlinearly from the distal end to the proximal end; or the diameter of the pin head decreases piecewise linearly from the distal end to the proximal end.

6. The engagement assembly for delivering an implant of claim 1, wherein the pin head is a tapered or frusto-tapered pin head.

7. The engagement assembly of claim 6, wherein the conical surface of the tapered or frusto-tapered pin head is angled from the central axis by no more than 30 degrees.

8. The engagement assembly for delivering an implant of claim 1, wherein the first elongate delivery member is a guide wire and the second elongate delivery member is a tubular member over the guide wire.

9. The engagement assembly for delivering an implant according to claim 8, wherein the tubular member is a hypotube.

10. The engagement assembly for delivering an implant according to claim 1, wherein the proximal end of the pin element is fixedly attached to the first elongate delivery member by welding, adhesive bonding, hinging, and/or snapping, and the proximal end of the proximal pusher is fixedly attached to the second elongate delivery member by welding, adhesive bonding, hinging, and/or snapping.

11. The engagement assembly for delivering an implant according to claim 1, wherein the pin element further comprises a pin handle connected to the pin head, the pin head being fixedly connected to the first elongate delivery member via the pin handle; the opening is in clearance fit with the pin shank.

12. The engagement assembly for delivering an implant according to claim 1, wherein the proximal pusher has a cylindrical outer surface; the diameter of the distal-most end of the pin head is less than the diameter of the cylindrical outer surface of the proximal pusher.

13. The engagement assembly for delivering an implant of claim 1, wherein the bore has a diameter that is less than a diameter of a proximal-most end of the pin head.

14. A core assembly for delivering an implant, comprising an engagement assembly for delivering an implant according to any of claims 1-13, further comprising: the first elongate delivery member and the second elongate delivery member.

15. A system for delivering an implant, comprising the core assembly for delivering an implant of claim 14, further comprising the catheter and the implant.

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