JP2023087459A - stent delivery device - Google Patents

Abstract

To provide a stent delivery device capable of making development of a stent smooth by regulating the movement of the stent.SOLUTION: A stent delivery device (delivery device 1) includes an inner sheath 30, a friction material 10 disposed on an outer peripheral surface of the inner sheath 30, a stent (stent graft 2) attached around the inner sheath 30, and an outer sheath 31 for covering the inner sheath 30, the friction material 10, and the stent graft 2 from the outside in a radial direction. The outer sheath 31 is configured so as to relatively move in an axial direction with respect to the inner sheath 30 to a position for covering the stent graft 2 and to a position for exposing the stent graft 2. The stent graft 2 is provided so as to cover the friction material 10.SELECTED DRAWING: Figure 2

Description

The present invention relates to a stent delivery device for medical use and for delivering a stent into the body.

2. Description of the Related Art In medical practice, a stent delivery device is used to deliver an indwelling device such as a stent (including a stent graft) into the body. The sheath of the stent delivery device is inserted into the body in order to deliver such items into body passages (including digestive tracts, blood vessels, etc.). According to such a stent delivery device, the stent held within the sheath can be left in the body.

For example, Patent Literature 1 discloses a stent delivery device including an inner sheath, an outer sheath, and a stent provided between the inner sheath and the outer sheath as a device for delivering a stent into the body (in the same document, described as a stent delivery catheter.) is disclosed.
Furthermore, the step provided on the inner sheath serves as a stopper to prevent the stent from moving to the proximal end side together with the outer sheath when the outer sheath is moved to the proximal end side to expose the stent. It is stated that

JP-A-2008-86340

However, the step formed in the inner sheath described in Patent Document 1 and serving as the stopper abuts on the distal end of the outer sheath to restrict its movement. Therefore, when the outer sheath is retracted, the stent, which is about to be retracted along with the outer sheath, comes into contact with the step and is compressed by the reaction force applied from the step, which increases the packing density. This increased loading density increases the deployment load.

In other words, since the frictional load increases when the outer sheath is pulled proximally, there is room for improvement in terms of smooth deployment of the stent.

SUMMARY OF THE INVENTION The present invention has been made in view of the problems described above, and provides a stent delivery device capable of regulating the movement of the stent and smoothing the deployment of the stent.

The stent delivery device of the present invention comprises an inner sheath, a friction material disposed on the outer peripheral surface of the inner sheath, a stent attached around the inner sheath, the inner sheath, the friction material and the stent. and an outer sheath that radially covers the stent from the outside, wherein the outer sheath is configured to be axially movable relative to the inner sheath between a position covering the stent and a position exposing the stent. and the stent is provided so as to cover the friction material.

By applying friction from the friction material to the stent, it is possible to prevent the stent from moving along with the outer sheath and from increasing the deployment load. A delivery device can be provided.

FIG. 3 is a schematic diagram showing a state in which a stent graft is indwelled in the aortic arch by a stent delivery device (delivery device). FIG. 4 is a cross-sectional view of the distal end of the sheath with the stent graft retracted; FIG. 10 is a side view showing the surroundings of the inner sheath after retracting the outer sheath and detaching the stent graft. FIG. 5 is a side view showing a friction material according to a first modified example; FIG. 11 is a side view showing a friction material according to a second modified example;

A stent delivery device (delivery device 1) according to an embodiment of the present invention will be described below.
The drawings used in this embodiment illustrate the configuration, shape, and arrangement of each member of the stent delivery device of the present invention, and do not limit the present invention.
Also, the drawings do not necessarily accurately represent the dimensional ratios such as the length, width, and height of the stent delivery device (delivery device 1).
In addition, the proximal side (base end side) refers to the side arranged near the operator during treatment, and the distal side (tip side) refers to the side arranged far from the operator during treatment.
Moreover, in all the drawings, the same constituent elements are denoted by the same reference numerals, and overlapping descriptions are omitted as appropriate.

<Overview>
Prior to the description of this embodiment, first, the outline of a stent delivery device (delivery device 1) according to this embodiment will be described mainly with reference to FIGS. 1 and 2. FIG. FIG. 1 is a schematic diagram showing a state in which a stent graft 2 is placed in the aortic arch by a stent delivery device (delivery device 1), and FIG. 2 is a cross-sectional view of a distal end portion 3a of a sheath 3 with the stent graft 2 retracted. is.

A stent delivery device (delivery device 1) according to the present embodiment includes an inner sheath 30, a friction material 10 disposed on the outer peripheral surface of the inner sheath 30, and a stent (stent graft 2) attached around the inner sheath 30. ), and an outer sheath 31 that covers the inner sheath 30, the friction material 10, and the stent graft 2 from the outside in the radial direction.
The outer sheath 31 is configured to be axially movable relative to the inner sheath 30 between a position covering the stent graft 2 and a position exposing the stent graft 2 . The stent graft 2 is provided so as to cover the friction material 10 .

In other words, the inner sheath 30, the friction material 10, the stent graft 2, and the outer sheath 31 are provided in this order outward from the radial center of the sheath 3 (the inner sheath 30 and the outer sheath 31).
The "friction material 10" is a material that restricts the movement of the stent graft 2 inscribed in the outer sheath 31 by friction when the outer sheath 31 is retracted to the proximal side with respect to the inner sheath 30. etc. are optional. The friction material 10 according to this embodiment is a cylindrical resin material.
A "stent" is a stent graft 2 comprising a stent portion 2a and a resin graft portion 2b in the blood vessel described in this embodiment. However, the stent is not limited to such a structure, and for example, when it is used for respiratory system or digestive system body canals, it is composed only of the stent part 2a without the graft part 2b. There may be.

According to the above configuration, the stent (stent graft 2) is provided so as to cover the friction material 10, so that when the outer sheath 31 moves to a position where the stent graft 2 is exposed (regressed), the stent graft 2 is Friction from the friction material 10 is added. Therefore, it is possible to prevent the stent graft 2 from being dragged by the outer sheath 31 and retreating.
Therefore, the stent graft 2 can be easily deployed and placed at a desired position.

Furthermore, when the stent graft 2 is retracted and compressed before the pusher 6, the loading density increases. This increased loading density increases the deployment load. That is, the friction material 10 suppresses the retraction of the stent graft 2 by the friction, thereby preventing the stent graft 2 from being prevented from being deployed due to an increase in the frictional load when the outer sheath 31 is pulled proximally. .

<Configuration of each part>
The configuration of each part of the delivery device 1 will be described mainly with reference to FIG. 3 in addition to FIGS. FIG. 3 is a side view showing the surroundings of the inner sheath 30 after the outer sheath 31 has been retracted and the stent graft 2 has been withdrawn.
The delivery device 1 delivers a stent graft 2 into the body (intracorporeal canal). and are mainly provided.
The placement site of the stent graft 2 by the delivery device 1 in this embodiment is the site of the aortic arch 50 shown in FIG. 1 where the aortic aneurysm 40 is located.

The stent graft 2 according to this embodiment is attached to the inner sheath 30, and is exposed from the sheath 3 when the outer sheath 31 is moved proximally relative to the inner sheath 30 by the operator. .
The stent graft 2 is composed of a stent portion 2a made of metal (for example, made of a nickel-titanium alloy) and a graft portion 2b made of resin. A portion of the stent portion 2a is arranged in a mesh within the graft portion 2b, and another portion of the stent portion 2a extends from the distal end portion and is attached to the distal end portion of the inner sheath 30. As shown in FIG.

The sheath 3 is composed of an inner sheath 30 having a distal tip 5 at its distal end, and an outer sheath 31 covering the outer periphery of the inner sheath 30 and attached to the inner sheath 30 so as to move forward and backward in the axial direction. .
In this embodiment, the guide wire 34 is passed through the inner sheath 30 and guided to the indwelling site of the stent graft 2 in the aortic arch 50 .
As shown in FIG. 2, the pipe 7, two friction members 10, and the distal tip 5 are attached to the outer peripheral surface of the inner sheath 30 according to the present embodiment in order from the base end side.

The pipe 7 connects the inner sheath 30 and the pusher 6 in the radial direction and is provided between them. In this embodiment, the pipe 7 partially (half) protrudes from the tip of the pusher 6 and is fixed to the inner sheath 30 .

A coil-shaped proximal marker 14 made of an X-ray opaque material such as tungsten is provided on the distal end side of the pipe 7 so that the position of the distal end portion of the pusher 6 can be recognized during X-ray irradiation. is buried.
With the proximal marker 14 , the portion of the pusher 6 that is likely to be located on the most proximal side of the stent graft 2 can be identified.
Note that the proximal marker 14 may be fixed to the outer circumference of the pipe 7 with an adhesive.

The friction material 10 is formed axially longer than the pipe 7 and is formed radially thicker than the pipe 7 . The friction material 10 is fixed to the inner sheath 30 with an adhesive or the like on the outer periphery of the inner sheath 30 .
However, the friction material 10 is not limited to such a configuration, and may be fitted to the outer circumference of the inner sheath 30 in an elastically deformed state (in other words, in a state in which residual stress remains).
In other words, it suffices if it is attached to the inner sheath 30 to such an extent that it does not move with the movement of the stent graft 2 .

In the graft portion 2b of the stent graft 2, the portion protruding proximally with respect to the friction material 10 at the proximal end is shorter than the portion protruding distally with respect to the frictional material 10 at the distal end.
In other words, the two friction materials 10 are arranged biased toward the proximal end side with respect to the graft portion 2b as a whole.

Further, the friction material 10 on the distal end side is provided on the proximal side from the position on the distal side from the distal end of the pusher 6 by the axial length of the graft portion 2 b of the stent graft 2 .
By disposing the friction material 10 in this manner, the range where the friction material 10 on the distal end side slides against the stent graft 2 that tends to move toward the proximal end side along with the outer sheath 31 is widened.

An intermediate marker 15 formed in a coil shape is attached to the outer circumference of the inner sheath 30 between the two friction materials 10 in the axial direction and inside the graft portion 2 b of the stent graft 2 .

The intermediate marker 15 is made of tungsten, for example, and is fixed to the central portion of the graft portion 2b of the stent graft 2 housed in the sheath 3 between the two friction materials 10 with an adhesive or the like. By configuring the intermediate marker 15 in this manner, it is possible to specify a site with a high probability that the stent graft 2 whose movement is restricted by the two friction materials 10 will be located during X-ray irradiation. The intermediate marker 15 is made of an X-ray opaque material that allows the position of the stent graft 2 to be recognized during X-ray irradiation.

Furthermore, a coil-shaped distal side marker 16 is attached to a portion overlapping the distal tip 5 on the outer circumference of the distal end portion of the inner sheath 30 .
The distal side marker 16 is made of tungsten, for example, and is provided at a portion overlapping the distal tip 5 (embedded in the distal tip 5). By arranging the distal marker 16 in this way, it is possible to specify the site of the distal tip 5 during X-ray irradiation, which is useful when advancing the sheath 3 into the body vessel. The distal side marker 16 is made of an X-ray opaque material that allows the position of the stent graft 2 to be recognized during X-ray irradiation.

The pusher 6 restricts the movement of the stent graft 2 on the proximal side, and is arranged at a position overlapping the stent graft 2 accommodated in the outer sheath 31 in the radial direction. In this embodiment, the inner surface of the pusher 6 is sized to contact the outer surface of the pipe 7, and the outer surface of the pusher 6 is formed to have a smaller diameter than the inner surface of the outer sheath 31. It is formed in a size that is spaced apart from the

<First modification>
Next, mainly referring to FIG. 4, the friction members 11 and 12 according to the first modified example will be described. FIG. 4 is a side view showing friction members 11 and 12 according to a first modified example.
A plurality of friction materials 11 and 12 according to this example are arranged in the axial direction of the inner sheath 30 and are all covered with a stent (similar to the configuration related to the stent graft 2 shown in FIG. 2).
Each of the plurality of friction members 11 and 12 according to this example has outer peripheral surfaces 11a and 12a that are inclined so as to widen radially outward toward the distal end side of the inner sheath 30 .
In other words, the friction materials 11 and 12 have tapered portions 11b and 12b that are tapered toward their distal ends.

As described above, the outer peripheral surfaces 11a and 12a of the friction members 11 and 12 are formed so as to widen radially outward toward the distal end side of the inner sheath 30 . With such a configuration, it is possible to secure a frictional force against the stent graft 2 at the large-diameter portion on the distal end side, and to enhance position retention when the stent graft 2 is loaded into the outer sheath 31 .

As described above, the friction members 11 and 12 are formed in a reverse tapered shape.
That is, the proximal end sides of the outer peripheral surfaces 11a and 12a of the friction members 11 and 12 are formed to have a smaller diameter than the distal end sides. By forming the friction materials 11 and 12 in this way, the portion facing the proximal side of the friction material 11 including the stent graft 2 covering it has a smaller diameter than the portion facing the distal side. Therefore, after the stent graft 2 is attached to the friction materials 11 and 12, the outer sheath 31 can smoothly cover the radially outer side of the stent graft 2 from the base end side thereof.

It is preferable if the "friction material" is formed in this way, but the friction material according to the present invention is not limited to such a shape.
In other words, when the outer sheath 31 is moved proximally with respect to the inner sheath 30 in order to expose the stent graft 2, the friction material according to the present invention moves the stent graft 2 along with the outer sheath 31. It would be good if it could be suppressed.
For example, the friction material may be formed in a rectangular parallelepiped shape having a through hole through which the inner sheath 30 is passed, in addition to being formed in a cylindrical shape. It may be formed in an oblong or elliptical shape when viewed from the side, or may have a tapered outer peripheral surface as described later.

As shown in FIG. 4, for at least two of the plurality of friction materials 11 and 12, the inclination (inclination angle α) of the outer peripheral surface 11a of the friction material 11 on the proximal side of the inner sheath 30 It is gentler (smaller in inclination angle) than the inclination (inclination angle β) of the outer peripheral surface 12a of the friction material 12 on the tip side.

However, the configuration is not limited to this, and the inclination angles of the outer peripheral surfaces of the friction members 11 and 12 may be the same. Furthermore, although two of the plurality of friction materials 11 and 12 are provided in this example, more may be provided.
In addition, regarding the inclination of the outer peripheral surfaces 11a, 12a of the friction materials 11, 12, the inclination of at least a part of the outer peripheral surfaces 11a, 12a in contact with the stent graft 2 at the same distance from the central axis of the inner sheath is compared. include.

According to the configuration shown in FIG. 4, the inclination of the outer peripheral surface 11a of the friction material 11 on the proximal end side is gentler than the inclination of the outer peripheral surface 12a of the friction material 12 on the distal end side. Therefore, the friction material 11 on the proximal end side can increase the frictional force when the stent (stent graft 2 ) is about to move while being dragged by the outer sheath 31 . Therefore, it is possible to more preferably restrict the stent graft 2 from retreating over the friction material 11 .

<Second modification>
Next, mainly referring to FIG. 5, the friction material 13 (, 12) according to the second modification will be described. FIG. 5 is a side view showing a friction material 13 (, 12) according to a second modification.
A plurality of friction materials (12, 13) according to this example are arranged in the axial direction of the inner sheath 30, and all of them are covered with a stent (similar to the configuration related to the stent graft 2 shown in FIG. 2).
Regarding at least two of the plurality of friction materials (friction materials 12 and 13), the maximum diameter portion 13c of the friction material 13 on the proximal end side of the inner sheath 30 is the maximum diameter of the friction material 12 on the distal end side of the inner sheath 30. It is formed longer in the axial direction than the diameter portion 12c.

Specifically, the friction material 13 is formed in a trapezoidal shape when viewed from the side, and its outer peripheral surface 13a extends axially from a tapered portion 13b on the proximal side and a large-diameter portion of the tapered portion 13b. and a maximum diameter portion 13c.
The maximum diameter portion 12c of the friction material 12 according to this example is the edge portion of the tapered portion 12b, but is not limited to such a configuration, and has a certain length in the axial direction of the inner sheath 30. may

In the above configuration, the maximum diameter portion 13c of the friction material 13 on the base end side of the inner sheath 30 is axially longer than the maximum diameter portion 12c of the friction material 12 on the distal end side of the inner sheath 30. As shown in FIG. With this configuration, the range in which the frictional force is applied from the friction material 13 on the proximal side to the stent graft 2 can be widened, and the stent graft 2 can be easily fixed at a predetermined position on the proximal side.

In the above-described embodiment, the delivery device 1 is described as one for placing the stent graft 2 in a blood vessel, which is a body canal. For example, it may be indwelled in a respiratory system, a digestive system, or any other organ system (digestive tract, etc.). For example, the delivery device 1 may be used through an endoscope.

It should be noted that the various constituent elements of the delivery device of the present invention do not need to exist individually. that a plurality of constituent elements are formed as one member, that one constituent element is formed of a plurality of members, that a certain constituent element is part of another constituent element, or that a certain constituent element is one It is permissible for a part and a part of another component to overlap, and so on.

The above embodiments include the following technical ideas.
(1)
an inner sheath;
a friction material disposed on the outer peripheral surface of the inner sheath;
a stent mounted around the inner sheath;
an outer sheath that radially covers the inner sheath, the friction material, and the stent;
The outer sheath is configured to be axially movable relative to the inner sheath between a position covering the stent and a position exposing the stent,
A stent delivery device, wherein the stent is provided so as to cover the friction material.
(2)
The stent delivery device according to (1), wherein the friction material has an outer peripheral surface that is inclined so as to widen radially outward toward the distal end side of the inner sheath.
(3)
A plurality of the friction materials are arranged in the axial direction of the inner sheath and are all covered with the stent,
each of the plurality of friction materials has an outer peripheral surface inclined so as to expand radially outward toward the distal end side of the inner sheath;
Regarding at least two of the plurality of friction materials, the inclination of the outer peripheral surface of the friction material on the proximal end side of the inner sheath is greater than the inclination of the outer peripheral surface of the friction material on the distal end side of the inner sheath. The stent delivery device according to (2), which is also gentle.
(4)
A plurality of the friction materials are arranged in the axial direction of the inner sheath and are all covered with the stent,
With respect to at least two of the plurality of friction materials, the maximum diameter portion of the friction material on the proximal end side of the inner sheath is axially greater than the maximum diameter portion of the friction material on the distal end side of the inner sheath. The stent delivery device according to any one of (1) to (3), which is elongated.
(5)
A plurality of the friction materials are arranged in the axial direction of the inner sheath and are all covered with the stent,
The stent delivery device according to any one of (1) to (4), wherein radiopaque markers are provided between the plurality of friction materials in the inner sheath.

1 Delivery device (stent delivery device)
2 Stent graft (stent)
2a stent section 2b graft section 3 sheath 3a tip section (distal section)
5 tip 6 pusher 7 pipe 10 friction material 11 friction material 11a outer peripheral surface 11b tapered portion 12 friction material 12a outer peripheral surface 12b tapered portion 12c maximum diameter portion 13 friction material 13a outer peripheral surface 13b tapered portion 13c maximum diameter portion 14 proximal side marker 15 intermediate marker 16 distal marker 30 inner sheath 31 outer sheath 34 guide wire 40 aortic aneurysm 50 aortic arch

Claims (5)

an inner sheath;
a friction material disposed on the outer peripheral surface of the inner sheath;
a stent mounted around the inner sheath;
an outer sheath that radially covers the inner sheath, the friction material, and the stent;
The outer sheath is configured to be axially movable relative to the inner sheath between a position covering the stent and a position exposing the stent,
A stent delivery device, wherein the stent is provided so as to cover the friction material. 2. The stent delivery device according to claim 1, wherein the friction material has an outer peripheral surface that is inclined so as to expand radially outward toward the distal end of the inner sheath. a plurality of the friction materials are arranged in the axial direction of the inner sheath and are all covered with the stent;
each of the plurality of friction materials has an outer peripheral surface inclined so as to expand radially outward toward the distal end side of the inner sheath;
With respect to at least two of the plurality of friction materials, the inclination of the outer peripheral surface of the friction material on the proximal end side of the inner sheath is greater than the inclination of the outer peripheral surface of the friction material on the distal end side of the inner sheath. 3. The stent delivery device of claim 2, wherein the tension is also gentle. a plurality of the friction materials are arranged in the axial direction of the inner sheath and are all covered with the stent;
With respect to at least two of the plurality of friction materials, the maximum diameter portion of the friction material on the proximal end side of the inner sheath is axially greater than the maximum diameter portion of the friction material on the distal end side of the inner sheath. 4. The stent delivery device according to any one of claims 1 to 3, wherein the stent delivery device is elongated. a plurality of the friction materials are arranged in the axial direction of the inner sheath and are all covered with the stent;
5. The stent delivery device according to any one of claims 1 to 4, wherein the inner sheath is provided with X-ray opaque markers between the plurality of friction materials.

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