Stent And Stent Connection Interface
A stent with a common connection interface, and a method and platform used to create a stent with a common connection interface is described. A common connection interface used to connect a stent to a pusher is described.
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This application is a continuation of and claims priority to U.S. patent application Ser. No. 16/920,227 filed Jul. 2, 2020 entitled Stent And Stent Connection Interface, which is a continuation of and claims priority to U.S. patent application Ser. No. 16/127,136 filed Sep. 10, 2018 entitled Stent And Stent Connection Interface (now U.S. Pat. No. 10,736,760 issued Aug. 11, 2020), which claims benefit of and priority to U.S. Provisional Application Ser. No. 62/563,570 filed Sep. 26, 2017 entitled Stent with a Single End Loop, all of which are hereby incorporated herein by reference in their entireties.
BACKGROUND OF THE INVENTIONStents are used for various therapeutic purposes within the vasculature, including opening vessels, flow diversion to limit blood flow to a problematic region such as an aneurysm, or as a scaffold to retain other therapeutic material within a target region.
Delivery of stents can be difficult for several reasons. Many stents end in a looped end configuration with a plurality of loops and most stent delivery systems must connect to one or more of these loops to deliver the stents. Stent delivery systems which hold all the loops are difficult since the stents are delivered through relatively small catheters, leaving little room for a delivery design which can grip all the loops. Delivery designs or systems which hold only one loop of the several loops are problematic since the stent is only being partially controlled during delivery. Since stents generally have shape-memory and therefore adopt their expanded shapes quickly once they are released from the delivery catheter, positioning and repositioning stents after delivery is also an issue.
SUMMARY OF THE INVENTIONThe following embodiments deal with a stent connection interface which allows multiple stent loops/flares to combine into a common connection, thereby allowing for easier control over a stent during the delivery process.
In one embodiment, a stent connection interface is described. The stent connection interface combines pairs of end stent loops into a common connection.
In one embodiment, a stent is described. The stent has end loops on at least the proximal end of the stent, and the end loops converge into a common connection region by a stent connection interface. The stent connection interface, in turn, connects to a stent delivery mechanism (e.g., a pusher) which is used to control and deliver the stent.
In one embodiment, a stent is described where the stent has a plurality of end loops converging into a common connection region/interface.
In one embodiment, a stent delivery system is described. The delivery system comprises a pusher used to mechanically grasp and position the stent. The stent utilizes a stent connection interface to create a common connection out of a plurality of end loops, the common connection is connected to the pusher where the pusher is used to position the stent.
In one embodiment, a method of creating a stent having a common connection is described. The method comprises taking a stent having a plurality of end loops and connecting a stent connection interface which combines pairs of end loops into a common connection area.
In one embodiment, a mandrel is described which is used to create a stent having a common connection. The mandrel includes a plurality of grooves which accommodate a plurality of stent wires, and the plurality of grooves are patterned such that multiple wires coalesce into a common connection interface.
In one embodiment, a scaffold is described which is used to create a stent having a common connection. The scaffold includes a plurality of channels which accommodate a plurality of stent wires, and the plurality of channels are patterned such that multiple wires coalesce into a common connection interface.
In one embodiment, a stent delivery system is described where the stent delivery system has a pusher which attaches to and detaches from a common connection of a stent.
These and other aspects, features and advantages of which embodiments of the invention are capable of will be apparent and elucidated from the following description of embodiments of the present invention, in which:
Stents are used for a variety of reasons in the vasculature. For example, propping open vessels to restore blood flow, flow diversion to limit blood flow to a problematic region such as an aneurysm, or as a scaffold to retain other therapeutic material within a target region. Many stents use a plurality of end loops or end flares (e.g., radially flared loops) at either end of the stent; wherein the end loops or flares help anchor the vessel to a particular spot in the vasculature to minimize the chance that the stent will move after deployment. U.S. Pat. Nos. 9,867,725 and 9,439,791 disclose various stent embodiments having end loops or flares, and both patents are hereby incorporated by reference in their entirety.
FIG. 1 shows one example of a stent having a number of end loops at either end of the stent that can radially flare outwards from the main body of the stent in its expanded configuration. These end loops/flares can be created in a number of ways. For example, the stent can have a one-layer or two-layer configuration. In one example, further described in U.S. Pat. Nos. 9,867,725 9,439,791 which were earlier incorporated by reference, the stent has an inner and outer layer, where the outer layer is comprised of a wire braid wound over a mandrel to impart a number of flares or loops which protrude from the stent at both ends. A stent can also utilize a single layer comprised of one or more wires wound into a particular pattern, where each end of the stent includes a number of flares or loops. Such a stent is described in the patents referenced and incorporated by reference above.
Other stents can utilize a dual or two-layer configuration where the outer layer is formed of a series of wire pairs where each wire pair forms a flare or loop at the ends of the stent. One such stent utilizing this configuration is described in US Published Application No. 2017/0079812, which is hereby incorporated by reference in its entirety.
Stent 100 shown in
In one embodiment, shown in
Delivering a stent with these end loops can be difficult since each loop represents a different and separate grasping interface. Designing a delivery system that can grasp all of the loops can be challenging since each loop represents a different contact interface spread circumferentially and peripherally around the stent. Meanwhile, utilizing a delivery system that mechanically grasps only one of the several loops can limit control of the stent during the delivery process since only a small portion of the stent is being physically controlled. The following embodiments seek to address this problem by utilizing a connection interface which connects to these end loops or flares to create a common connection region which is then connected to a delivery system to deliver the stent.
Stent 100 is preferably comprised of metallic wire, meaning the stent itself as well as the end loops on either end of the stent are comprised of metallic wire such as nitinol—although other variations could involve the stent being comprised of different materials such as polymers. Alternative stent construction configurations could also utilize DFT or drawn-filled tubing, which is typically comprised of a radiopaque core (e.g. platinum, tantalum, gold, silver, titanium or tungsten wire/element) surrounded by a thin metallic (e.g. nitinol) jacket—DFT offers the advantage of radiopacity, so a stent comprised of DFT where the DFT comprises some or all of the metallic mesh will have heightened radiopaque imaging properties and will not necessarily need additional radiopaque wires/coils to aid in visualization. In one embodiment, the stent is a dual layer stent having an inner layer and an outer layer, where the flares at both ends of the stent are located on the outer layer. The outer layer, which includes long flares 104 and short flares 107, is preferably made of a multiple wire braid where pairs of wires converge to create the triangular flares best shown in
Alternatively, each wire can be fish-hooked or bent back at the ends, and then passed through the other wire as shown in
To create the stent winding pattern and shape, a mandrel is used where the wires comprising the stent are wound over the mandrel to create the stent shape. The stent is often then heat set over the mandrel to impart a shape memory into the stent, such that the stent will adopt its expanded, shape memory configuration when deployed from a delivery catheter. The following embodiments utilize a mandrel with a number of grooves to accommodate the stent wires. The grooves are arranged in a particular pattern such that the groove pattern converges into a common connection region such that the stent flares converge into a common connection region which can then be held by an implant pusher/delivery system. In this way, a stent is created whereby a plurality of flares merge to a common connection region to make stent delivery easier.
Since the flares 104, 107 are generally enlarged and protrude relative to the stent 100 (as shown in
The tapered sections 114a and 116a contain a number of pins 118 protruding radially and perpendicularly outwardly from the surface. The wires forming the stent/stent layer are wound around the pins to create the loop shapes. Where the stent has a series of short loops 107 and long loops 104, the pin locations are radially spread out such that some pins 118a are radially further out, and some pins 118b are radially closer. Pins 118a that are radially further out are used to wind the long loops 104 and pins 118b that are radially closer are used to wind the short loops 107. In other embodiments where the flares or loops are all of a similar size, pins along a similar radial location (e.g., only pins 118b or only pins 118a) are used to wind the various stent loops—alternatively, in such embodiments, the mandrel is configured only with one set of pins (e.g., either pins 118b or pins 118a) so that the stent is solely wound around a set of similarly-placed radial pins to create a stent with equally sized end loops or end flares.
The pins are used to impart the flared or loop shapes in the following manner. In one embodiment, the one or more wires comprising the relevant stent/stent layer would be wound around the pins to impart the particular flared loop shape, such that the wire is bent around the pin and wound back into the stent to impart the flared or looped shape. One example where this embodiment can be used is where the relevant stent or stent layer incorporating the flares is made of one wire, such that the one wire is continuously woven back and forth and around the pins. Another example is where the relevant stent or stent layer is comprised of multiple wires but each wire is used to wind a loop or flare at each end of the stent, where one wire is used to create one loop at one end of the stent and wound back to create another loop at the other end of the stent, a second wire is used to create a second loop at one end of the stent and a second loop at the other end of the stent—in this manner, an stent with 8 loops at either end (8 loops at one end, and 8 loops at the other end) would comprise 8 wires, or one for each loop. In some embodiments, the flared loops are formed of wire pairs, and the loops can be made in different ways. For instance, the wire pairs are welded or capped at their ends beyond the pin location. Alternatively, one of the wires would be pulled backwards proximal of the pin and then welded or affixed to the other wire comprising the wire pair. With these embodiments, the loops are formed from two distinct wires coming together and then affixed to each other to create the loop or flared shape.
In order to create a common connection point or common connection region from the plurality of end flares or loops at one end of the stent, one of the mandrel sections would contain a series of channels or grooves to accommodate the stent wires, where the wires would be placed into a particular pattern etched or cut into the mandrel to funnel the plurality of wires into a pattern that ends in a common connection point. These channels or grooves could be created in a number of ways—for instance, laser-cutting, etching, and mechanical cutting. Note, only one of the mandrel sections would need the groove pattern and not both since the groove pattern is used only on one end of the stent since only one end of the stent (e.g., the proximal end that is meant to be connected to the delivery pusher/delivery system) needs the common connection interface.
This mandrel concept is shown in
In the groove pattern shown in
In an alternate embodiment, the 4 wires 120c, 120h, 120k, 120p forming common connection region 121 can further be condensed. For instance, wire 120c and wire 120h can be attached to each other, and wires 120k and 120p can also be attached to each other, creating a common connection region comprising two wires. These two wires can then optionally be attached to each other at another location to produce a common connection region comprising one more. Therefore, although
After the wires are placed into these grooves, the portion of the wires sitting beyond the grooves are trimmed since different wires will have different lengths corresponding to the respective groove lengths. For example, the stent wire sitting in groove 120b would be shorter than the stent wire sitting within groove 120c since groove 120c is longer, therefore the portion of the stent wire sitting beyond the end of the groove 120b will be trimmed. After this trimming step is taken, the stent itself can be heat set to impart a shape memory and then the wires are removed from the mandrel. The wires still have to be removed from the grooves and attached to each other at their respective groove locations, therefore, for example, wire 120b is attached along longer wire 120c. This attachment can be done in a number of ways—for instance, via welding, adhesive, crimp, or solder. Alternatively, a mechanical connection interface such as an overlying cylindrical tube which has an internal diameter large enough to contain the various wires can be used to bind two or more wires. In an alternative arrangement, the heat setting step to impart the shape memory can be taken after the various wires are attached to each other to create the “step-down” pattern culminating in common connection region 121.
With the mandrel configuration shown in
Though the mandrels have primarily been described as having grooves or channels to accommodate the wires, alternative configurations can utilize a series of wire holding elements placed over the mandrel where the holders/holding elements form the grooves/channels to accommodate the wires. In this way, a guiding interface is formed to guide the wires, however no cuts or recesses on the mandrel would be necessary, rather the guide channels would simply be built over the particular section of the mandrel. In one embodiment, the guiding interface is a scaffold that is placed over the mandrel and the mandrel can contains recesses, where a removable pin or retention element is used to temporarily secure the scaffold to the recesses of the mandrel. In this way, the overlying guide interface can be temporarily affixed over the mandrel to guide the stent wires into a pattern like the pattern shown in
Alternatively, a scaffolding interface can connect to the loops of the stent where the scaffolding interface has the guide holders described above to guide the particular wires in a particular way, where the wires sit within the guide holders. With this embodiment, there would be no need for a scaffold or guiding interface to be “built over” the mandrel, rather the mandrel section would terminate with the part of the mandrel accommodating the loops. The scaffold interface would then be placed adjacent to the end loops, where the scaffold interface is comprised of a series of holders forming a pattern corresponding to the groove interface embodiments shown in
Alternatively still, the scaffolding interface can adopt a mandrel configuration but not actually be part of the physical mandrel itself which is used to wind the stent. The scaffolding interface would be a circular element with a wire-holding pattern cut into the surface (as grooves) or built over the interface (as protruding holding elements). In this embodiment, the scaffolding interface is best thought of as a detached, movable mandrel which can be placed adjacent to the end stent loops/flares, such that the stent wires can then be drawn through the wire guides of the movable mandrel.
In another embodiment, the entire groove pattern illustratively shown in
Some of the embodiments presented herein utilize a separate wire structure or laser-cut structure which connects to the stent flare region to create a common connection interface. For example, a scaffold or frame structure which connects to the stent flares to guide the stent wires in a particular direction.
The following embodiments utilize an alternative configuration to link the stent flares together, these embodiments utilize using wires to link the stent flares together in a ring like pattern and then connecting a common connection interface to this ring-like pattern. Since the flares form a generally circular pattern around the end of the stent, as shown in
In another embodiment, half of the stent flares are connected with a first wire or series of wires and half of the remaining stent flares are connected with a second wire or series of wires. This can be thought of as a first linked “half-ring” and a second linked “half-ring”. Each half-ring will have its own connected common connection interface, therefore a two-wire common connection interface is created, where a first wire is connected to the first half-ring, and a second wire is connected to the second half-ring.
In another embodiment, a braid of wires is used to connect the various flares together and this braid of wires forms a generally circular pattern connecting the various stent loops/flares together, where this wire braid forms the ring-type shape. In another embodiment, the short flares are all connected by one or more wires and the long flares are separately connected by one or more wires such that both the short flares and long flares are separately combined by two separate rings. Another binding structure, such as a wire, then connects the two rings.
In another embodiment, a circular pattern is utilized to connect the various flares, however the circular pattern is tapered. This configuration is shown in
Alternatively, the common connection interface 121 can comprise a number of wires 154 which directly connect to the stent flares and converge to a common connection point—as shown in
Please note, different stent flare embodiments are discussed earlier where some embodiments utilize a pair of wires converging to form a stent flare, and other embodiments utilize a single wire which creates a looped or flared end shape. In the latter concept, the wire comprising the flared loop 104a is cut to create a gap and the separate wire 154 would then be connected in this region. In another embodiment, this connection element is directly connected to the stent loop 104a such that two additional wires forming the “V” shape connect to the stent loop and wire element 154 is connected within this V-shape to compress the stent flare region down to a one wire element 154. The difference here is that the wire element 154 is connected to another crown element built over the stent flare 104a rather than the wire element 154 being directly connected to the stent flare. This configuration is best shown in
The preceding description focused on the mandrel and/or frame, groove interface, and techniques used to create a stent having a common connection region at one end of the stent, where several wires condense down into a smaller group of wires forming a common connection region 121. The following description will discuss how the common connection region interacts with the delivery pusher to connect the stent to the delivery pusher.
Stents are generally connected to a mechanical pusher, which takes the form of a rod or tube used to push the stent through a delivery catheter and to the target region. With the stents described herein which utilize a common connection interface, the stent 100 will taper down to a common connection interface 121, and this common connection interface 121 then connects to a pusher 134—as shown in
As shown in
The earlier description discussed the common connection interface 121 as comprised of four wires, but also mentioned how alternative wire arrangements could condense the common connection interface 121 down into two or even one wire.
An alternative embodiment is presented in
Another alternative embodiment is presented in
The attachments between wires can be created in a number of different ways as discussed earlier, including adhesives, ties, and welding (e.g., spot welding). Multiple spot welds in different locations along the length of the connected wires can be used to enhance the connection strength, or one weld point can be used to allow more flexibility between the two wires. Since the attachment locations will be somewhat stiff due to the presence of the attachment medium, the attachment points can be spread out or staggered along a particular wire (e.g. along a longer wire 120c which is one of the wires comprising common connection interface 121) to spread out the location of these locally stiffer areas.
Alternative embodiments similar to the deployment system of
The earlier description discussed the use of certain metallic materials for potential use within the stent, such as nitinol or drawn-filled tubing. In some embodiments, particular parts of the stent, such as the stent flares and/or the common connection interface described earlier can utilize radiopaque wires or DFT to selectively aid in imaging in this particular region of the stent body.
Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention. Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof.
Claims
1. A stent delivery system, comprising:
- a pusher for delivering a stent, wherein a distal portion of the pusher includes a first ring member; and
- a connection interface including a second ring member positioned between the pusher and the stent, the connection interface being proximally linked to the pusher and distally linked to the stent; and,
- wherein the first ring member engages with the second ring member such that the pusher may be linked with the stent.
2. The stent delivery system of claim 1, wherein the first ring member and the second ring member intersect each other when engaged.
3. The stent delivery system of claim 1, wherein the first ring member is comprised of a thread.
4. The stent delivery system of claim 1, wherein the first ring member is comprised of a suture.
5. The stent delivery system of claim 1, further comprising an electrode connected to the pusher for severing the first ring member.
6. The stent delivery system of claim 5, wherein the electrode is positioned proximal to the first ring member.
7. The stent delivery system of claim 5, wherein the first ring member is comprised of a thread or a suture.
8. The stent delivery system of claim 1, wherein the first ring member may be electrolytically disengaged from the second ring member.
9. The stent delivery system of claim 1, wherein the first ring member may be thermolytically disengaged from the second ring member.
10. A stent delivery system, comprising:
- a pusher for delivering a stent, wherein a distal portion of the pusher includes a first ring member; and
- a connection interface including a second ring member positioned between the pusher and the stent, the connection interface being proximally linked to the pusher and distally linked to the stent; and,
- wherein, in a first configuration, the first ring member is engaged with the second ring member; and,
- wherein, in a second configuration, the first ring member is disengaged from the second ring member.
11. The stent delivery system of claim 10, wherein the first ring member and the second ring member intersect each other when in the first configuration.
12. The stent delivery system of claim 10, wherein the first ring member may be electrolytically disengaged from the second ring member.
13. The stent delivery system of claim 10, wherein the first ring member may be thermolytically disengaged from the second ring member.
14. The stent delivery system of claim 10, wherein the connection interface extends proximally from the stent.
15. The stent delivery system of claim 10, wherein the stent is distally spaced away from the pusher by the connection interface when in the first configuration.
16. The stent delivery system of claim 1, further comprising an electrode connected to the pusher for severing the first ring member.
17. The stent delivery system of claim 16, wherein the first ring member is comprised of a thread or a suture.
18. A stent delivery system, comprising:
- a pusher means for delivering a stent, wherein a distal portion of the pusher means includes a first ring member; and
- a connection interface means for linking the pusher means with the stent, the connection interface means including a second ring member positioned between the pusher means and the stent, and the connection interface means being proximally linked to the pusher means and distally linked to the stent;
- wherein, in a first configuration, the first ring member is engaged with the second ring member; and,
- wherein, in a second configuration, the first ring member is disengaged from the second ring member.
19. The stent delivery system of claim 18, further comprising an electrolytic means for disengaging the first ring member from the second ring member.
20. The stent delivery system of claim 18, further comprising a thermolytic means for disengaging the first ring member from the second ring member.
Type: Application
Filed: Dec 6, 2022
Publication Date: Mar 30, 2023
Applicant: MicroVention, Inc. (Aliso Viejo, CA)
Inventor: Ponaka Pung (Aliso Viejo, CA)
Application Number: 18/062,491