JP2004089382A - Stent graft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stent graft which is suitably used to a bent in vivo tubular organ by simply joining a stent and a graft with each other and securing the flexibility and expansibility of the stent graft. <P>SOLUTION: Both of the ends 2a of the graft 2 are fixed to both of the ends 1a of the stent 1, and the other part, the graft 2 is freely wound onto the stent 2. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a structure of a stent graft to be retained at a safe site of an affected area in order to treat a stenotic disease and a dilated disease (aneurysm) or other diseases of an artery.
[0002]
[Prior art]
Aneurysms that occur due to hardening or inflammation of the arteries gradually expand and become a disease with a poor prognosis that leads to fatal rupture if left unattended. Surgical procedures that have been used, such as aneurysm surgery and replacement surgery, have been used. However, this disease is common in the elderly, frequently occurs with multiple organ disorders (disorders in the brain, heart, kidneys, etc.), and the surgical operations are often overly invasive. For this reason, application of endovascular treatment using a sheath that is relatively invasive to surgery has attracted attention. As one of the applied examples, treatment using a stent graft is performed.
[0003]
A stent graft is an artificial tubular structure that is inserted into a body organ such as a blood vessel to support the body organ such as a blood vessel. Stent grafts, for example, are inserted into tubular bodies such as blood vessels, gall bladder, esophagus, intestine, and urethra when they are stenotic or deformed, and by supporting the tubular body, the stenosis or deformation is suppressed. To prevent. A stent graft widely used clinically for the purpose of treating arterial stenosis is a tubular body made of stainless steel or a wire made of a shape memory alloy (NiTi) or made of a net or a spring. The tubular body is capable of repeatedly contracting and expanding in the radial direction. The stent graft is an intravascular insertion type artificial product made by suturing and fixing a tubular body formed by a mesh or a spring made of stainless steel or nickel titanate wire into an artificial blood vessel made of polyester or Teflon (R). Blood vessels. Stent grafts have been effectively used to treat aneurysms. Such a stent graft is disclosed, for example, in JP-A-07-024072, JP-T-07-500272, JP-A-08-299456, JP-T-08-502428, and JP-T-08-511487. And JP-A-2000-262632.
[0004]
Such a stent graft is placed in a disease in a blood vessel via a sheath. That is, the stent graft is compressed to a diameter smaller than the inner diameter of the thin sheath, stored in the sheath, and inserted into an affected part in a blood vessel through an incision in a peripheral artery (mainly a femoral artery). Therefore, the stent graft is pushed out of the sheath, radially expanded to a predetermined diameter, and placed in the affected part of the blood vessel, thereby expanding the arterial stenosis and closing the aneurysm, and at the same time, reconstructing the blood flow I do.
[0005]
[Problems to be solved by the invention]
Conventional stent grafts have various structures to enable contraction and expansion. For example, Japanese Patent Application Laid-Open No. 2000-262632 has a plurality of elastic rings in which a zigzag bent metal wire is formed in a ring shape, these elastic rings are arranged at intervals in the axial direction, and are connected by connecting wires. are doing.
In this publication, the following problems are encountered when used in the treatment of arterial stenosis and dilatation disease (aneurysm) or other diseases by inserting it into a largely bent internal tubular organ. was there.
[0006]
When inserted into highly bent internal tubular organs such as the arch aorta, the distal arch aorta, the distal descending aorta (on the diaphragm) and the abdominal artery, the inner curve of the aorta neighbours in the stent. The mating bends of the elastic rings come into contact with or intersect each other via the graft, creating wrinkles in the graft that impede blood flow or, in the worst case, clots. There was a problem of causing it. In addition, if the stent graft is left in place for a while, the temporary placement stent graft is bent to match the bending of the blood vessel and is tightly fixed to the inner wall of the blood vessel in that state. When trying to retract the stent graft into the catheter, there is a problem that the graft damages the inner wall of the blood vessel.
[0007]
In addition, a stent in which one or a plurality of wires are helically twisted to form a braided structure is also known. Such a braided structure is extremely flexible, and is suitably used even for a large bent portion. However, since the stent was sewn to the graft with a thread, joining was difficult.
[0008]
As a simple joining method of the stent and the graft, a stent coated with the graft can be considered. In addition, a method of setting and manufacturing a stent in a graft mold is conceivable. According to this joining method, the method of bonding the stent and the graft is easy, but there is a problem that the adhesion between the two is too strong and the expansion and contraction properties are insufficient.
[0009]
The present invention provides a technique capable of easily joining a stent and a graft and ensuring the expandability and contraction of the stent graft, with the aim of solving the problems of the conventional techniques.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 comprises a tubular stent and a graft surrounding the outer periphery of the stent, and both ends of the graft are fixed to both ends of the stent, Since the graft is surrounded in a free state with respect to the stent except for the both ends, the joining method between the graft and the stent is easy, and the graft is sufficiently provided with flexibility and elasticity and expandability. It can be suitably used for organs.
[0011]
The invention according to claim 2 can be applied to a part of the stent graft according to claim 1 which does not require a graft because the graft is partially formed with an opening.
[0012]
The invention according to claim 3 can be suitably applied to a blood vessel having a branch tube, since the stent graft according to claim 1 has a plurality of through-holes opened in the graft.
[0013]
In the invention according to claim 4, the stent is provided in a cylindrical shape, the graft is provided in a C-shaped cross section, and a slit-shaped notch is formed in the longitudinal direction of the graft, so that the degree of freedom of expansion and contraction is high, In addition, it can be easily used except for unnecessary portions of the graft.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an example in which the stent graft according to the first embodiment of the present invention is applied, and is an example in which a stent graft is implanted transcatheterly into an entry (E) generated in the periphery of the left subclavian artery. FIG. 1A shows a preoperative state. FIG. 1 (b) shows a state in which a wire (PT) is passed from the right upper arm artery to the right femoral artery, and the catheter (sheath) is inserted to the center of the entry (E) using the wire (PT) as a guide. FIG. 1C shows a state in which the stent graft (SG) inserted into the catheter sheath is implanted in such a manner as to bypass the entry (E).
[0015]
FIG. 2 shows the stent graft used in FIG. The stent 1 is made of an elastic ring made of stainless steel, titanium, nickel titanate, or the like, and has a diameter of 0.4 to 0.8 mm. The outer diameter of the stent 1 when expanded is 20 to 40 mm, and its length is 30 to 100 mm. The graft 2 is made of urethane rubber, polyester, Teflon (R), or the like. The stent 1 is passed through the graft 2, and the axial ends 2 a of the graft 2 are joined to the axial ends 1 a of the stent 1. As a joining method, adhesion, suture joining with a thread such as polypropylene, or the like is possible.
[0016]
In the present invention, the axial end portions 1a of the stent 1 and the axial end portions 2a of the graft 2 are merely joined, and they can freely expand and contract in the axial direction, and the expansion and contraction do not interfere with each other. Therefore, as shown in FIG. 1, it can be suitably used for an entry (E) generated in the periphery of the left subclavian artery.
[0017]
FIG. 3 shows a stent graft according to the second embodiment, and is a view similar to FIG. The difference from the stent graft of FIG. 2 is that a through hole 13 is opened in the middle of the graft 12. Note that the stent 11 is formed in a cylindrical shape as in FIG.
When a stent graft is set in a blood vessel to close a defective portion, a well-branched blood vessel may be blocked by the stent graft. In such a case, it is necessary to perform an operation such as connecting the blood vessel by bypassing the good blood vessel from another place, but by using the stent graft of the second embodiment, a good branched blood vessel can be obtained. Since it can be used as it is, the number of surgical sites can be reduced.
It should be noted that the stent 11 may be provided with a through-hole corresponding to the portion of the graft 12 where the through-hole 13 is provided.
[0018]
FIG. 4 shows a stent graft according to the third embodiment, which is similar to FIG. In the third embodiment, the stent graft graft 22 is formed not in a cylindrical shape but in a C-shaped cross section, a slit-shaped notch 23 is formed in the axial direction, and the stent 21 is formed in a cylindrical shape. If the stent graft of the third embodiment is used for, for example, an entry (E) generated in the left subclavian artery of FIG. 1, it is essential to close the entry (E). What is necessary is just to set so that the part which is not provided with the notch 23 may be applied to that part. In this case, since the wrapping force of the stent 21 by the graft 22 is weaker than those of the first and second embodiments, the stent 21 easily expands in the radial direction according to the shape of the blood vessel. In addition, the shape easily adapts to a greatly bent blood vessel.
[0019]
【The invention's effect】
In the present invention, the stent includes a tubular stent and a graft surrounding the outer periphery of the stent, and both ends of the graft are fixed to both ends of the stent. Since it is surrounded in a free state, the method of joining the graft and the stent is easy, and it has sufficient flexibility and elasticity, and can be suitably used for a bent internal tubular organ.
[Brief description of the drawings]
FIG. 1 shows an example using a stent graft according to a first embodiment of the present invention, wherein (a) shows a preoperative state, (b) shows a state in which a catheter sheath has been inserted up to the entry center, and (c) Is a state where the stent graft is implanted.
FIG. 2 shows a stent graft according to the first embodiment.
FIG. 3 shows a stent graft according to a second embodiment.
FIG. 4 shows a stent graft according to a third embodiment.
[Explanation of symbols]
1, 11, 21 Stent 2, 12, 22 Graft 13 Through-hole 23 Slit

Claims (4)

A tubular stent and a graft surrounded by the outer periphery of the stent, wherein both ends of the graft are fixed to both ends of the stent, and other than the both ends of the graft are free from the stent. A stent graft characterized by being surrounded. The stent graft according to claim 1, wherein an opening is partially formed in the graft. 2. The stent graft according to claim 1, wherein a plurality of through holes are opened in the graft. 2. The stent graft according to claim 1, wherein the stent is provided in a cylindrical shape, the graft is provided in a C-shaped cross section, and a slit-shaped notch is formed in a longitudinal direction of the graft.

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