JP2002263194A - Stent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stent which can be inserted to and detained at the branching position of tubular tissues by a simpler operation. SOLUTION: This stent is composed of a main stent 12 and a branch stent 20. The main stent 12 is composed of the enlarged diameter tubular part 14 of a high expansion rate, whose outside diameter when being expanded is large and the reduced diameter tubular part 16 of an expansion rate lower than that of the enlarged diameter tubular part 14, whose outside diameter when being expanded is smaller than that of the enlarged diameter tubular part 14. The enlarged diameter tubular part 14 and the reduced diameter tubular part 16 are integrally connected. At the boundary part of the enlarged diameter tubular part 14 and the reduced diameter tubular part 16, an opening 18 is formed at the enlarged diameter tubular part 14 and the branch stent 20 can be engaged with the opening 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for indwelling a tubular tissue such as a blood vessel, an esophagus, and a trachea of a body at a bifurcation site to secure an inner diameter in the vicinity of the bifurcation site, or for an aneurysm part near the bifurcation site. The present invention relates to a stent for indwelling and reinforcing a blood vessel.

[0002]

2. Description of the Related Art Conventionally, as this kind of stent, for example, a stent described in Japanese Patent Application Laid-Open No. H11-319110 is known. The stent disclosed in this publication is formed in a tubular shape, and is composed of a main tube having a large outer diameter and two branch tubes which branch off from the main tube and have a smaller outer diameter than the main tube. ing. The main body tube and the branch tube are integrally formed, and the stent has a shape that matches the shape of the branch site of the tubular tissue to be placed as a whole.

[0003]

However, in order to properly place the above-described stent having a complicated shape corresponding to the branch portion of the tubular tissue having a complicated shape at the branch portion,
There is a problem that the operation is not easy. For example, according to the insertion / detention procedure described in this publication, first, the stent is inserted into the distal end portion of the introduction sheath in a reduced diameter state. At that time, the outer diameter expanding means for expanding the main tube and one branch tube is drawn out from the base end of the introduction sheath, and the outer diameter expanding means for expanding the other branch tube is introduced. It is folded back in the sheath and pulled out from the distal end of the introduction sheath. Sheaths are inserted from the left femoral artery and the right femoral artery, respectively, and their tips are taken to the bifurcation of the aorta, and the introduction sheath is introduced through the sheath inserted from the right femoral artery, while the left femoral artery is inserted. The grasping instrument is inserted through the inserted sheath. Then, the introduction sheath is advanced into the right iliac artery, and the grasping device is advanced into the left iliac artery. The outer diameter expanding means is gripped by a gripping instrument.
Then, the introduction sheath is pulled out, the stent in the reduced diameter state is positioned in the aorta, and the grasping device is pulled out of the body together with the outer diameter expanding means. Respectively, position the body tube at the lower end of the aorta and position the branch tubes within the right and left iliac arteries, respectively. After positioning of the stent in this way, the outer diameter expanding means is operated, respectively, to maintain the main tube and the branch tube in the expanded state, respectively.

In this procedure, in the aorta, the work of grasping the outer diameter expanding means with the grasping instrument or dividing the two branched tubes into the right iliac artery and the left iliac artery, respectively, is performed. Operations such as placement cannot be easily performed under conditions of strong blood flow and pulsation.

[0005] The present invention has been made in view of the conventional problems, and an object of the present invention is to provide a stent that can be inserted and placed at a bifurcation of a tubular tissue with a simple and reliable operation.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a stent which can be inserted and placed at a bifurcation of a tubular tissue, the stent comprising at least one main stent which is a separate member. The main stent comprises a diameter-expanded tubular portion and a diameter-reduced tubular portion whose expansion rate is smaller than the diameter-expanded tubular portion and whose outer diameter when expanded is smaller than the diameter-expanded tubular portion. The enlarged-diameter tubular portion and the reduced-diameter tubular portion are integrally connected, and at a boundary portion between the enlarged-diameter tubular portion and the reduced-diameter tubular portion, at least one opening is formed in the enlarged-diameter tubular portion. The at least one branch stent is engagable with the at least one opening.

The main stent is housed in a reduced diameter within a catheter or sheath, inserted into the tubular tissue, and exits the catheter or sheath at the bifurcation of the tubular tissue.
Detain. At this time, since the expansion rate is different between the enlarged tubular portion and the reduced tubular portion, the enlarged tubular portion has a large diameter and is in an enlarged state, and is positioned in the main tube of the tubular tissue.
The reduced-diameter tubular portion expands at a smaller expansion rate than the expanded-diameter tubular portion and is positioned at one of the branch tubes of the tubular tissue. Due to the difference in diameter between the main tube and the branch tube of the tubular tissue, the main stent and the branch tube are fitted with the enlarged tubular portion and the reduced tubular portion, respectively, so that the main stent is swept away by rapid blood flow and pulsation. Without stopping at the branch site. At this time, the opening formed at the boundary between the enlarged-diameter tubular portion and the reduced-diameter tubular portion communicates with another branch pipe, and communication between the other branch pipe and the main pipe is maintained. Next, a catheter or sheath containing the bifurcated stent is inserted into the tubular tissue,
Insert into another branch tube and at the bifurcation of the tubular tissue,
Engage with the opening. In this way, a stent suitable for the shape of the bifurcation of the tubular tissue can be easily and reliably placed at the bifurcation.

According to a second aspect of the present invention, there is provided a stent component which can be inserted and placed in one of a main pipe and a single branch pipe at a branch site of a tubular tissue, wherein the expanded tubular portion and the expansion rate are expanded. A reduced-diameter tubular portion having a diameter smaller than the diameter-shaped tubular portion and having an outer diameter smaller than the enlarged-diameter tubular portion when expanded, wherein the enlarged-diameter tubular portion and the reduced-diameter tubular portion are integrally connected, At the interface between the radial tubular portion and the reduced tubular portion, the enlarged tubular portion is formed with at least one opening for receiving at least one bifurcated stent.

According to a third aspect of the present invention, there is provided a stent constituent member of a stent which can be inserted and placed mainly in a branch tube at a branch portion of a tubular tissue, wherein the main tube and one branch tube at the branch portion of the tubular tissue are provided. The expanded diameter tubular portion and the reduced diameter tubular portion having a smaller expansion rate than the expanded diameter tubular portion and an outer diameter when expanded and smaller than the expanded diameter tubular portion are integrally connected to each other, The main stent has an opening formed at a boundary portion between the portion and the reduced-diameter tubular portion, and an engaging portion for engaging with the opening is formed at a distal end portion.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. The following embodiments do not limit the present invention.

FIG. 1 is a view showing a stent according to the present invention. In this embodiment, a stent 10 is divided into a main stent 12 and a branch stent 20 which are separate members. The main stent 12 includes the expanded tubular portion 1 having a large outer diameter.
4 and a reduced diameter tubular portion 16 having a small outer diameter, which are integrally connected along the axial direction, that is, along the tube axis of the tubular tissue. In addition, the branch stent 20
The outer diameter of the main stent 12 is almost the same as that of the reduced-diameter tubular portion 16.

The main stent 12 and the bifurcated stent 20 are
From the pantograph, coil, bent, mesh, lattice, or any other shape of the wire, the wires are bound together at appropriate locations to form a sheet, and furthermore, it is made into a tube. Can be configured.
FIG. 8 is a development view of the main stent 12. Main stent 12
In the above, the enlarged diameter tubular portion 14 is smaller than the reduced diameter tubular portion 1.
The knitting method is rougher than the knitting method 6, so that the expanded tubular portion 14 can obtain a larger expansion rate than the reduced diameter tubular portion 16.

The material of the wire is stainless steel,
Tantalum, platinum, shape memory alloy (Ni-Ti, C
u-Al-Ni system, Cu-Zn-Al system, Pd-Ti
System, Be-Cu system, amorphous, etc.), plastic or plastic monofilament (polyester, polyurethane, polyolefin, polytetrafluoroethylene, porosiloxane, shape memory resin, etc.).

The main stent 12 has an opening 18 in the enlarged diameter tubular portion 14 at the boundary between the enlarged diameter tubular portion 14 and the reduced diameter tubular portion 16. This opening 18 is for receiving a bifurcated stent 20.
A protruding engaging portion 20a is formed around the distal end opening of the branch stent 20, and an opening engaging portion 18a around which the protruding engaging portion 20a is locked is formed around the opening 18.
It has become. Contrary to the illustration, a protruding engagement portion may be formed around the distal end opening 18 of the branch stent 20, and an open engagement portion may be formed around the opening 18.

Although not shown, the main stent 12
A cover may be provided on the outside of the bifurcated stent 20 to make the stent 10 a covered stent (stent with an artificial blood vessel). For example, the stent 10 may be suitable for placement in an aneurysm part. it can. As the material of the cover, any of polyester, silicone resin, polytetrafluoroethylene, polyolefin, polyurethane, polyvinylpyrrolidone, polyhydroxymethyl methacrylate and the like can be selected, and the main stent 12 and the branch are formed by dipping or casting. Coat the outside of the stent 20.

A procedure for inserting and placing the stent 10 configured as described above at the bifurcation of the tubular tissue will be described with reference to FIGS. In this example, a case will be described in which a stent is placed in an aneurysm portion at a bifurcation of an aorta, which is a tubular tissue.

First, the main stent 12 is housed in the sheath 22 and is reduced in diameter around the flexible wire 24 in the sheath 22. At this time, the diameter is reduced to the same diameter so that both the enlarged-diameter tubular portion 14 and the reduced-diameter tubular portion 16 are accommodated in the sheath 22. Similarly, the bifurcated stent 20 is also inserted into another sheath 22 and has a reduced diameter around the flexible wire 22 within the sheath 22.

As shown in FIG. 2, after inserting the sheath 22 from the femoral artery of one leg and moving it to the bifurcation of the aorta, the outer cylinder of the sheath 22 is pulled out and the flexible wire 24
(FIG. 3).
The extruded main stent 12 is expanded in diameter due to self-expandability. At this time, since the expansion rate of the enlarged diameter tubular portion 14 is larger than that of the reduced diameter tubular portion 16, the enlarged diameter tubular portion 14 has a large diameter and is in an enlarged state, and is positioned in the main tube of the tubular tissue. The radial tubular section 16 is the expanded tubular section 1
It is in the expanded state at an expansion rate smaller than 4, and is positioned at one of the branch tubes of the tubular tissue (see FIG. 4). At this time,
Since there is a difference in diameter between the main tube M and the branch tube B1 of the tubular tissue, and the expanded tubular portion 14 and the reduced diameter tubular portion 16 fit into the main tube and the branch tube, respectively, the main stent 12 can provide a fast blood flow. And stays at the bifurcation without being swept away by pulsation. At the same time, the opening 18 keeps the blood flow of the tubular tissue to the other branch tube B2 unhindered.

Next, the sheath 22 into which the branch stent 20 has been inserted is inserted through the femoral artery of the opposite leg (FIG. 5).
reference). After moving the sheath 22 to the branch site of the aorta and inserting the distal end of the sheath 22 into the opening 18,
By pulling out the outer cylinder of the sheath 22, the branch stent 20 around the flexible wire 24 is pushed out (see FIG. 6). As a result, the diameter of the branch stent 20 is expanded by self-expansion while passing through the opening 18. The engaging portion 20a of the branch stent 20 is engaged with the engaging portion 18a of the opening 18, and the branch stent 20 is connected to the main stent 12 (see FIG. 7).
Alternatively, by setting the size of the branch stent 20 in the expanded state to be slightly larger than that of the opening 18, the branch stent 20 is engaged with the opening 18, and
Oa and the engaging portion 18a can be omitted.

Thus, the stent 10 suitable for the shape of the bifurcation of the tubular tissue can be placed. Even when the stent 10 is exposed to a rapid blood flow or pulsation, the stent 10 is securely placed for a long period of time.

In the above embodiment, the main stent 12
The number of the openings 18 at the boundary between the enlarged diameter tubular portion 14 and the reduced diameter tubular portion 16 is one. However, the number is not limited to one, and a plurality of openings 18 may be provided in accordance with the number of branches of the tubular tissue where the stent is to be placed. Can be provided so that each branch stent is engaged with each opening.

[0022]

As described above, according to the present invention, by using a main stent (or a constituent member of a stent) and at least one branch stent (or a constituent member of a stent) which are separate members, It can be simply and reliably placed in accordance with the bifurcation of the tissue.
Thus, the operation time can be reduced, and the burden on the patient can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a stent of the present invention.

FIG. 2 is a diagram illustrating a procedure for placing the stent of FIG. 1;

FIG. 3 is a diagram illustrating a procedure for placing the stent of FIG. 1;

FIG. 4 is a diagram illustrating a procedure for placing the stent of FIG. 1;

FIG. 5 is a diagram illustrating a procedure for placing the stent of FIG. 1;

FIG. 6 is a diagram illustrating a procedure for placing the stent of FIG. 1;

FIG. 7 is a view showing a procedure for placing the stent of FIG. 1;

FIG. 8 is a development view of the main stent 12.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Stent 12 Main stent 14 Large diameter tubular part 16 Reduced diameter tubular part 18 Opening 18a Engaging part 20 Branch stent 20a Engaging part

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tadamasa Miyauchi 40, Shimachi, Gifu-shi, Gifu F-term in the First Surgery, Faculty of Medicine, Gifu University 4C167 AA42 AA45 AA50 AA51 AA53 BB01 BB02 BB03 BB05 BB08 BB17 BB21 BB26 CC09 CC10 DD01 GG05 GG06 GG08 GG22 GG24 GG32 HH30

Claims (3)

[Claims] 1. A stent insertable and indwellable at a bifurcation site of a tubular tissue, comprising a main stent and at least one bifurcation stent, each of which is a separate member, wherein the main stent comprises: An expansion ratio is smaller than the enlarged-diameter tubular portion and a reduced-diameter tubular portion whose outer diameter when expanded is smaller than the enlarged-diameter tubular portion, and the enlarged-diameter tubular portion and the reduced-diameter tubular portion are integrally connected. Wherein at the interface between the enlarged tubular portion and the reduced tubular portion, at least one opening is formed in the enlarged tubular portion, wherein the at least one branch stent engages the at least one opening. A stent characterized in that it can be used. 2. A stent component that can be inserted and placed in a main tube and one branch tube at a branch site of a tubular tissue,
An enlarged-diameter tubular portion, and a reduced-diameter tubular portion having an expansion rate smaller than the enlarged-diameter tubular portion and having an outer diameter when expanded that is smaller than the enlarged-diameter tubular portion. And the portion is integrally connected, and at the boundary between the enlarged tubular portion and the reduced tubular portion, the enlarged tubular portion is formed with at least one opening for receiving at least one bifurcated stent. A constituent member of a stent characterized by the above-mentioned. 3. A stent constituent member of a stent which can be inserted and placed mainly in a branch pipe at a branch portion of a tubular tissue, wherein the stent component is placed in a main tube and one branch pipe at a branch portion of the tubular tissue, and has an expanded tubular portion. The reduced-diameter tubular portion having an expansion rate smaller than the expanded-diameter tubular portion and having an outer diameter smaller than the expanded-diameter tubular portion when expanded is integrally connected to each other, so that the expanded-diameter tubular portion and the reduced-diameter tubular portion are connected to each other. A main stent having an opening formed at a boundary portion, wherein an engaging portion for engaging with the opening is formed at a distal end portion of the main stent.