JP2022024124A - Stent graft having portion for fenestration - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stent graft that suppresses the interference of a stent row and a branch stent graft.

SOLUTION: A stent graft 1 comprises a stent 5 comprising multiple stent rows 3 and a graft 7 coming in contact with the stent, and is used for treatment of the aortic aneurysms in the aorta having a branched blood vessel. The stent graft has a portion 9 for fenestration to insert a branch stent graft for keeping the branched blood vessel in a region being not interfered with multiple stent rows among the grafts. In the stent graft, the portion for fenestration is the portion for making a window for inserting the branch stent graft in a position corresponding to a patient's branched blood vessel for embedding the stent graft. The portion graft for fenestration being the graft positioned in the portion for fenestration is superior in durability and elasticity rather than the graft region being the region except the partial graft for fenestration among the grafts.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a stent graft having a fenestrated portion.

Artificial blood vessel replacement and stent-graft interpolation are known to treat aortic aneurysms including branches. For stent-graft interpolation, for example, fenestrated or candelabra stent grafts are used. However, since the position of the branch differs depending on the patient, the required size and shape increase, so there is a problem in terms of manufacturing and dissemination.

Patent No. 5788542

A stent graft with a fenestrated portion that allows the branch stent graft to be inserted anywhere, for example, to preserve the branched blood vessels near the aortic aneurysm during the procedure was desired. The conventional stent graft has a problem that the stent row and the branch stent graft interfere with each other.

One of the embodiments disclosed herein relates to a stent graft.
This stent graft 1 is
Stent 5 containing a plurality of stent rows 3 and
Includes a graft 7 in contact with the stent.
The stent graft 1 has a fenestrating portion 9 that facilitates insertion of a branch stent graft, which is another stent graft, into a part of the graft 7. The fenestration portion 9 is a site where the branch stent graft does not interfere with the stent row of the stent graft.

Since the branch stent graft has a fenestrating portion that facilitates insertion into a part of the graft 7, the branch stent graft can be inserted using the fenestration portion without interfering with the stent row of the stent graft.

A preferred embodiment of this stent graft is that, of the plurality of stent rows 3, at least a part of the stent row around the fenestration portion, which is a stent row located around the fenestration portion, is not fixed to the graft 7. .. By doing so, it is possible to more effectively prevent the situation where the stent row and the branch stent graft interfere with each other.

A preferred embodiment of this stent graft is that the fenestration partial peripheral stent row 11 has a loop shape that does not form a plurality of mountain valley structures. Having such a structure, this stent graft can more effectively prevent the situation where the loop-shaped stent row and the branch stent graft interfere with each other.

A preferred embodiment of this stent graft is that the perimeter stent row 11 for fenestration has a wider spacing between the stent rows than the other stent rows. Having such a structure, this stent graft can more effectively prevent the situation where the stent row and the branch stent graft interfere with each other.

A preferred embodiment of this stent graft is
The fenestration partial graft, which is a graft located in the fenestration portion, is easier to puncture than the graft site in the region other than the fenestration partial graft among the grafts, and is excellent in durability and elasticity. Since it has such a structure, this stent graft has excellent durability and can prevent a situation where leakage occurs after insertion of a branch stent graft.

A preferred embodiment of this stent graft is
The window opening portion has an X-ray opaque marker fixing portion 19. .. With such a structure, this stent graft can identify the fenestrated part under fluoroscopy.

According to the present invention, it is possible to provide a stent graft having a fenestrating portion into which a branch stent graft can be inserted.

FIG. 1 is a conceptual diagram of a stent graft, which is one of the embodiments disclosed in this specification. FIG. 2 is a conceptual diagram showing an example of a stent row for opening a window having a structure different from that of an existing stent row. FIG. 3 is a conceptual diagram showing an example in which the spacing between the stent rows around the partial fenestration is wider than the spacing between the other stent rows. FIG. 4 is a conceptual diagram showing an example in which at least a part of the perimeter stent row for fenestration is not fixed to the graft. FIG. 5 is a conceptual diagram showing an example of a thickened graft of a portion corresponding to a window opening portion. FIG. 6 is a conceptual diagram showing an example of a thickened graft of a portion corresponding to a window opening portion. FIG. 7 is a conceptual diagram showing an example of a normal stent provided with a window portion for inserting a branch stent. FIG. 8 is a photograph instead of a drawing showing a state in which a hole is made in a stent graft. FIG. 9 is a photograph instead of a drawing showing a state in which a hole is made in a stent graft. FIG. 10 is a photograph that replaces the drawing showing an example of a stent graft having a branch stent graft. FIG. 11 is a photograph that replaces the drawing showing an example of a stent graft having a branch stent graft.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The present invention is not limited to the form described below, and includes the following forms appropriately modified by those skilled in the art to the extent obvious.

FIG. 1 is a conceptual diagram of a stent graft, which is one of the embodiments disclosed in this specification. As shown in FIG. 1, the stent graft 1 includes a stent 5 containing a plurality of stent rows 3 and a graft 7 in contact with the stent. Although the number of stent rows 3 varies depending on the stent graft, examples of the number of stent rows 3 are 2 or more and 50 or less, 4 or more and 20 or less, or 5 or more and 15 or less.

An example of this, the stent graft 1 has a tubular (cylindrical) structure extending along its axial direction (Z-axis direction). An example of the length of the stent graft 1 along the axial direction is 10 to 30 cm. This length varies depending on the application and target. An example of the outer diameter of the stent graft 1 when expanded is 20 to 50 mm.

The stent 5 is configured by using, for example, one or a plurality of wire rods (strand wires). The stent has, for example, a tubular (cylindrical) structure. The stent may have a plurality of stent rows 3. Each stent row may have a wavy shape with peaks and valleys, and each stent row may be annular. In the stent, the tubular structure is composed of a mesh structure, and such a tubular network structure may be formed by braiding wire rods in a predetermined pattern. A tubular mesh structure may be formed by arranging one or more wire rods that are bent in a zigzag shape and processed into a cylindrical shape.

As the material of the wire rod constituting the stent 5, a metal wire rod is preferable, and a shape memory alloy to which the shape memory effect and superelasticity by heat treatment are imparted is particularly preferable. As an example of the material of the wire rod, stainless steel, tantalum (Ta), titanium (Ti), platinum (Pt), gold (Au), tungsten (W) and the like may be used. Examples of shape memory alloys are nickel (Ni) -Ti alloys, copper (Cu) -zinc (Zn) -X (X = aluminum (Al), iron (Fe), etc.) alloys, Ni-Ti-X (X =). Fe, Cu, vanadium (V), cobalt (Co), etc.) alloy. Wire rod synthetic resin may be used. The wire may be a metal wire whose surface is coated with Au or Pt, for example.

The graft 7 has, for example, a cylindrical (cylindrical) shape as shown in FIG. 1 so as to cover (cover) at least a part of the stent 5 or to be located inside the stent 5. Be placed. For example, it is preferable that the graft 7 is arranged so as to cover the outer peripheral side of the stent 5 (wire rod). Each stent row 3 may be fixed to the graft.

The graft 7 may be connected (fixed) to the stent 5 by, for example, sewing, adhesion, or welding. In this case, the graft 7 preferably covers and connects the stent 5 so as not to affect the expansion and contraction of the stent 5. It should be noted that such a connecting portion between the graft 7 and the stent 5 may be appropriately provided at, for example, both end portions or intermediate portions of the stent 5.

Examples of such a graft 7 are a thermoplastic resin formed into a tubular shape by a molding method such as extrusion molding or blow molding, a knitted fabric made of a thermoplastic resin fiber formed into a tubular shape, or an ultrafine metal wire. A tubular thermoplastic resin or a non-woven fabric made of ultrafine metal, a tubular flexible resin sheet or porous sheet, and a resin dissolved in a solvent were formed into a thin tubular shape by an electrospinning method. It is a structure.

Examples of knitted fabrics are known knitted fabrics and woven fabrics such as plain weave and twill weave. Also, as the graft, one with folds such as crimping can be used. As the graft, a woven fabric of thermoplastic resin fibers formed in a cylindrical shape and a plain woven fabric of thermoplastic resin fibers formed in a tubular shape are preferable because of their excellent strength, porosity, and productivity.

Examples of thermoplastic resins are polyolefins such as polyethylene, polypropylene and ethylene-α-olefin copolymers, polyamides, polyurethanes, polyethylene terephthalates, polybutylene terephthalates, polycyclohexane terephthalates, polyesters such as polyethylene-2,6-naphthalate, and polyhoots. It is a resin with little durability and tissue reaction, such as a fluororesin such as polyethylene carbonate and propylene polyfluorofluoride. Of these, polyesters such as polyethylene terephthalate, which are chemically stable, have high durability, and have little tissue reaction, and fluororesins such as polyfluoroethylene and polyfluoropropylene are preferably used as materials for the ingredient fluff. be able to.

It is preferable to use a highly elastic material for the graft. Using a highly elastic material can prevent blood from leaking when the branch stent graft is inserted. However, it is preferable that the stent graft is a material that does not expand with blood pressure. The stent graft preferably expands when the puncture site is expanded to about 10 atm with a balloon, but does not expand with blood pressure. Such stent grafts are known.

The stent graft 1 has a fenestrating portion 9 that facilitates insertion of a branch stent graft, which is another stent graft, into a part of the graft 7. The fenestration part is the site where the branch stent graft is intended to be inserted. In the stent graft 1, the window opening portion 9 may be installed at an appropriate position. The number of the window opening portions 9 may be appropriately adjusted according to the target portion, and may be one location, two locations, or three or more locations. In addition, the window opening portion may be designed for each patient. Since it has a fenestrating part, this stent graft 1 can be branched by using a puncture / penetrating device according to the position of a bifurcated blood vessel or by irradiating a laser on a stent graft placed at a predetermined position such as an aorta. A window for inserting a stent graft can be created. The shape of the fenestration portion 9 may be appropriately adjusted according to the target branch stent graft. Examples of the shape of the window opening portion 9 are a circle, an ellipse, a rectangle with rounded corners, and a rugby ball. The size of the fenestration portion 9 may be designed in consideration of the shape of the target branch stent graft and the like. An example of the size of the window opening portion 9 is a shape that fits within a region of 0.2 cm or more and 4 cm or less in width and 0.5 cm or more and 10 cm or less in length, and 0.5 cm or more and 2 cm or less in width and 1.5 cm or more and 6 cm or less in length. A shape that fits within the region, a shape that fits within the region of 0.8 cm or more and 1.2 cm or less in width and 2 cm or more and 4 cm or less in length.

Since the branch stent graft has a fenestration part that makes it easy to insert the branch stent graft into a part of the graft 7, this stent graft inserts the branch stent graft by a puncture / penetration device or a laser according to the position of the bifurcated blood vessel using the fenestration part. You can make a window to do this. Then, using this window, the branch stent graft can be easily inserted without interfering with the stent row.

FIG. 2 is a conceptual diagram showing an example in which the stent row around the partial fenestration has a structure different from that of other stent rows. As shown in FIG. 2, a preferred embodiment of this stent graft is that the fenestration partial perimeter stent row 11 is looped without a plurality of mountain valley structures. In this aspect, it is preferable that the structure of the perimeter stent row 11 for fenestration is different from the structure of the other stent rows 3. That is, the perimeter stent row 11 for fenestration in this embodiment is intended to facilitate the creation of the fenestration portion 9, and the other stent rows 3 maintain elasticity and strength in the same manner as a normal stent. Is intended. An example of the shape of the perimeter stent row 11 for fenestration is a loop with an infinite structure of mathematical symbols (a structure with 8 lying down) or on a plane orthogonal to the axis of the stent (z axis). It is a ring-shaped one provided or a ring-shaped one provided on a plane diagonally intersecting the axis of the stent.

FIG. 3 is a conceptual diagram showing an example in which the spacing between the stent rows around the partial fenestration is wider than the spacing between the other stent rows. As shown in FIG. 3, a preferred embodiment of the stent graft is that the fenestration partial peripheral stent row 11 has a wider spacing between the stent rows than the other stent rows. By widening the width of the stent row, sufficient space for creating the window can be secured in advance. An example of the distance between the two peripheral stent rows 11 for fenestration is 0.5 cm or more and 4 cm or less, and may be 1 cm or more and 2 cm or less. The distance between the two perimeter stent rows 11 for fenestration may be 1.1 times or more and 3 times or less, 1.2 times or more and 2.5 times or less, or 1.4 times the distance between the other stent rows. It may be double or more and 2.4 times or less. In this example, as in FIG. 4, there may be a portion 15 of the stent that is not anchored to the graft.

FIG. 4 is a conceptual diagram showing an example in which at least a part of the perimeter stent row for fenestration is not fixed to the graft. As shown in FIG. 4, a preferred embodiment of this stent graft is that, of the plurality of stent rows 3, at least a part of the stent row 11 for fenestration, which is a stent row located around the fenestration portion 9. However, it is not fixed to the graft 7. The portion 15 of the stent that is not anchored to the graft facilitates drilling holes for the branch stent graft and prevents the stent row and branch stent graft from interfering with each other. This portion 15 is present only on the side of the fenestration partial peri-stent row 11 where the fenestration portion 9 is present, and the portion of the fenestration peripheral stent row 11 on the back side of the fenestration portion 9 is grafted. It may be fixed as. Further, while the other stent rows are fixed to the graft, the entire perimeter stent row 11 for fenestration may not be fixed to the graft. Normally, the fenestration portion 9 is located between the two fenestration partial peri-stent rows 11. In the perimeter stent row 11 for fenestration, the region near the fenestration portion 9 may not be fixed to the graft 7, and the portion distant from the fenestration portion 9 may be fixed to the graft 7. Of the total length (length of the extended wire) of the perimeter stent row 11 for fenestration, the portion that is not fixed to the graft 7 may be 5% or more and 70% or less, 10% or more and 50% or less, or 10 It may be% or more and 40% or less, 10% or more and 30% or less, and 15% or more and 30% or less. The portion not fixed to the graft 7 is preferably continuous. The portion that is not fixed to the graft 7 may exist around the portion where the window opening portion 9 exists, or may be located at a position deviated from the portion where the window opening portion 9 exists in consideration of ease of opening the window. May exist as the center. Since the region near the window opening portion 9 is not fixed to the graft 7, it becomes easy to form the window opening portion 9 in this portion.

FIG. 5 is a conceptual diagram showing an example of a thickened graft of a portion corresponding to a window opening portion. FIG. 6 is a conceptual diagram showing an example of a thickened graft of a portion corresponding to a window opening portion. A preferred embodiment of this stent graft is a graft 7 located in the fenestration portion 9. The fenestration partial graft is thicker than the graft site in the region other than the fenestration partial graft in the graft, or has excellent elasticity. It is a thing. By increasing the thickness of the graft or giving it elasticity, the strength of the graft can be reduced by creating a window, and the risk of breakage and blood leakage from the joint can be reduced. As shown in FIGS. 5 and 6, another graft 17 may be superimposed and fixed on the graft of the portion corresponding to the window opening portion. It is preferable that the partial graft for fenestration is easier to puncture than other sites. For example, by making the graft thicker than the graft site in the region other than the partial fenestration graft, the wobbling of the graft portion is suppressed, and it becomes easy to puncture a branch stent or an instrument for providing a hole for the branch stent.

A preferred embodiment of this stent graft is that the fenestration portion has an X-ray opaque marker fixing portion 19 to which an X-ray opaque marker is fixed. Since it has an X-ray opaque marker fixation part, it can be performed while confirming the position with X-rays when inserting a branch stent graft. The X-ray opaque marker is preferably one that does not affect the rigidity of the artificial blood vessel even after drying. Examples of X-ray opaque markers are iodinated poppyseed oil ethyl ester (Patent No. 5959118) and barium sulfate (Patent No. 4798662). The X-ray opaque marker fixing portion may be formed by sewing a thread containing the X-ray opaque marker to the graft.

This stent graft is implanted in the target patient. After that, make a hole in the window opening part. As shown in FIG. 7 as a reference example, it is a conceptual diagram showing an example in which the stent rows have the same shape and the spacing between the stent rows is constant. If the conventional stent graft is used as it is as shown in FIG. 7, a sufficient space for providing a branch stent cannot be secured due to the presence of the metal stent of the stent graft depending on the position of the hole in the fenestration portion. 8 and 9 are photographs that replace the drawings showing how a conventional stent graft is drilled. Then, the branch stent graft 21 is inserted into the hole. The branch stent graft is fixed to the stent graft by the expanding force of the branch stent graft. In this way, a stent graft having a branch stent graft can be placed in the patient's body. 10 and 11 are photographs that replace the drawings showing an example of a stent graft having a branch stent graft. In the examples of FIGS. 10 and 11, a hole for opening a window is accidentally made at an appropriate position, and a space for installing a branch stent is secured, but in actual clinical practice, the indicated position cannot be selected in this way. On the other hand, in the stent graft of this application, if the fenestration part is punctured, there is no obstacle in inserting, expanding and fixing the branch stent graft.

The present invention may be used in the field of medical devices.

1 Stent graft 3 Stent row 5 Stent 7 Graft 9 Opening part 11 Peripheral stent row for opening 15 Stents that are not fixed to the graft 17 Graft 19 Roentgen opaque marker fixing part 21 Branch stent graft

Claims (7)

A stent graft that includes a stent containing multiple rows of stents and a graft that contacts the stent and is used to treat an aortic aneurysm in an aorta with branched blood vessels.
The stent graft has a fenestrating portion for inserting a branch stent graft for preserving the branched blood vessel at a site of the graft that does not interfere with the plurality of stent rows.
The fenestration portion is a stent graft, which is a portion for creating a window for inserting a branch stent graft at a position corresponding to the branch blood vessel of the patient in which the stent graft is to be implanted.
The fenestration partial graft, which is a graft located in the fenestration portion, is a stent graft having better durability and elasticity than the graft site in the region other than the fenestration partial graft of the graft. The stent graft according to claim 1.
Of the plurality of stent rows, the stent row around the fenestration portion, which is a stent row located around the fenestration portion, is a stent graft in which at least a part thereof is not fixed to the graft. The stent graft according to claim 2.
The perimeter stent row for fenestration is a loop-shaped stainless steel that does not have multiple mountain valley structures. The stent graft according to claim 2.
The peripheral stent row for fenestration is the peripheral stent row for fenestration among the plurality of stent rows. The stent graft according to claim 1.
The fenestration partial graft, which is a graft located in the fenestration portion, is a stent graft that is thicker than the graft site in the region other than the fenestration partial graft in the graft. The stent graft according to claim 1.
The fenestration portion is a stent graft having an X-ray opaque marker fixation portion. The stent graft according to claim 1.
The fenestration part is a part for indwelling the stent graft at a predetermined position in the aorta and using a puncture / penetrating device according to the position of the bifurcated blood vessel or irradiating with a laser. ..

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