JP2003275326A - Intravascular expansion appliance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intravascular expansion appliance which can sufficiently expand and maintain a blood vessel without releasing cholesterol, etc., and can be easily guided even in the fine blood vessel in the brain, etc. <P>SOLUTION: The intravascular expansion appliance 1 formed by taking up a base film of a sheet shape formed of polyimide and drilled with a number of microholes to a tubular form is inserted into the distal end of a catheter 4, is guided to a constricted lesion region 6 of the blood vessel 5 and is discharged to there. The appliance 1 arranged in the region 6 is self-expanded by the elastic deformation that the appliance tends to return to the original sheet shape of the base film 2, by which the blood vessel 5 is expanded. The blood vessel 5 is internally coated with the base film 2 at this time and therefore the release of a deposit 7, such as the cholesterol, into the bloodstream is suppressed. Since the appliance 1 is easily deformed, the appliance can be easily guided even to the narrow blood vessel in the brain, etc. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intravascular dilation device for dilating a blood vessel in which stenosis has occurred due to arteriosclerosis or the like.

[0002]

2. Description of the Related Art Generally, in order to secure blood flow to a stenotic lesion site of a coronary artery that supplies nutrition to the heart, for example, a blood vessel that is narrowed due to arteriosclerosis, etc. The treatment is being expanded. BACKGROUND ART Conventionally, there is a balloon catheter as a typical medical device used for such treatment. A balloon catheter is a catheter having a small balloon attached to its tip. After guiding the tip of such a balloon catheter to a lesion site, the balloon is inflated to temporarily physically expand the blood vessel diameter to secure blood flow. This treatment method is widely used as percutaneous coronary artery dilation (PTCA), and it is expected that the dilated blood vessel diameter will be maintained for a long period of time even after removal of the balloon catheter. .

However, in reality, in about 30% to 40% of patients who have undergone dilatation with a balloon catheter, restenosis occurs in which the blood vessel diameter contracts again about 3 to 6 months after the operation. Stents have been developed for the purpose of suppressing the occurrence of such restenosis.

The stent is used for securing blood flow by being placed in a blood vessel which easily contracts. Most of the stents currently on the market are made of metal, and those made of stainless steel whose tube diameter is expanded by the above-mentioned balloon catheter are widely used. There is also a stent that can be self-expanded by using a shape memory alloy, nickel titanium alloy, and discharging it from the tip of the catheter.

[0005]

However, the conventional metal stent generally has a circular tubular shape in which the vessel wall is formed into a mesh shape, and the cholesterol accumulated in the vessel wall is expanded when the stenotic blood vessel is expanded. May be released through the gap. If such a release occurs in the cervix or the skull, there is a concern that cerebral infarction may be caused by blocking peripheral blood vessels in the brain.

Further, since the conventional stent is made of metal, it is hard and has a large volume, and it has been extremely difficult to guide it to a thin blood vessel such as in the brain.

The present invention has been made in view of the above-mentioned problems, and can sufficiently maintain the dilation of blood vessels without releasing cholesterol and the like, and can easily induce even thin blood vessels such as in the brain. It is an object of the present invention to provide an intravascular expansion device that can be used.

[0008]

In order to solve the above-mentioned problems, the invention of claim 1 provides an intravascular expansion tool for expanding the blood vessel by inserting it into a blood vessel, which has elastic deformability and a plurality of fine particles. It is configured by using a film having holes formed therein, and when it is inserted into a blood vessel in a rolled-up state, the blood vessel is expanded by a deployment force based on the elastic deformability.

According to a second aspect of the invention, in the intravascular expansion tool according to the first aspect of the invention, the cross section perpendicular to the direction of forming the micropores has a substantially circular shape of φ30 μm or more and φ100 μm or less.

According to a third aspect of the invention, in the intravascular expansion device according to the first or second aspect of the invention, the film is formed of polyimide.

According to a fourth aspect of the invention, in the intravascular expansion device according to the first or second aspect of the invention, the film is made of polyester.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an intravascular expansion device 1 according to the present invention.
FIG. The intravascular expansion tool 1 is configured by forming a large number of fine holes 3 in a base film 2 formed of a polymer material having high elastic strength and high strength, for example, polyimide. The base film 2 before winding has a rectangular thin sheet shape with one side of 1 cm to 2 cm, and its thickness is about 50 μm to 100 μm.
It is a degree.

The fine holes 3 have a diameter of 30 μm or more and 100 μm.
The following is a substantially circular hole. Preferably, the cross section perpendicular to the forming direction of the fine holes 3 is a circle having a diameter of 30 μm or more and 100 μm or less. The plurality of micropores (preferably a large number of micropores) 3 are provided such that the total area of all the micropores 3 (perforated area area) is 10% or more of the area of the base film 2. The fine holes 3 are formed in the base film 2 by laser processing, for example.

When the intravascular expansion device 1 of FIG. 1 is used as a medical device, first, the base film 2 needs to be wound into a tubular shape. FIG. 2 is a perspective view showing a state of a process of winding the intravascular expansion device 1. Figure 2
FIG. 2A shows a winding start state of the intravascular expansion device 1, and FIG. 2B shows a winding completion state. The base film 2 formed of a polymer material (here, polyimide) has elasticity and is easily wound into a tubular shape. In the winding completion state shown in FIG.
The intravascular expansion tool 1 has a cylindrical shape in which the base film 2 is wound in multiple layers and has a diameter of about 1 mm and a length of 1 cm to 2 cm.

Next, as shown in FIG. 2 (b), the intravascular dilation device 1 in a wound state is inserted into a blood vessel narrowed by arteriosclerosis, that is, a stenotic lesion site. 3 and 4
FIG. 4A is a schematic view and a cross-sectional view sequentially showing a process of guiding and placing the wound intravascular expansion device 1 at a stenotic lesion site. First, the wound intravascular dilation device 1 is placed inside a thin tube such as a catheter. The catheter used at this time may be a normal catheter without a balloon.

Next, as shown in FIG. 3 (a), the catheter 4 is used to position the inside of a predetermined blood vessel 5 (here, the blood vessel 5).
The intravascular dilation device 1 is guided to the vicinity of the stenotic lesion site 6). Then, at the position shown in FIG.
As shown in FIG.
Is discharged. The discharged intravascular expansion device 1 is shown in FIG.
As shown in (b), the blood vessel 5 is inserted into the stenotic lesion site 6 and placed at that position. Note that FIG. 4A is a sectional view taken along the line AA of FIG.

The intravascular dilatation device 1 discharged from the catheter 4 and placed in the stenotic lesion site 6 of the blood vessel 5 is self-expanded due to the property of the base film 2 and, as shown in FIG. Expand. That is, when the base film 2 made of polyimide is inserted into the blood vessel 5 while being rolled up in a tubular shape as shown in FIG. 2B, the base film 2 tries to return to the original sheet shape as shown in FIG. It has elastic deformability. Then, the intravascular expansion device 1 arranged at the stenotic lesion site 6 self-expands to fully expand the blood vessel 5 by the deployment force based on the elastic deformability which is the property of the base film 2. Note that FIG. 4B is a sectional view taken along the line BB of FIG. 3C.

Blood vessel 5 by self-expansion of the intravascular expansion device 1
The extension of is further explained. The self-expansion of the intravascular expansion device 1 is defined by the tubular shape of the blood vessel 5. In other words, the intravascular expansion device 1 self-expands until the developing force based on the elastic deformability for returning to the original sheet shape and the reaction force received from the tube shape of the blood vessel 5 are balanced. Figure 3
(C) and FIG. 4 (b) show a state in which the intravascular expansion device 1 is self-expanded and physically expanded the blood vessel 5 until its elastic force and the reaction force received from the blood vessel 5 are balanced. . In this state, since a cavity is formed inside the expanded intravascular expansion device 1, sufficient blood flow can be obtained (see FIG. 4 (b)).

By the way, at the stenotic lesion site 6, deposits 7 such as cholesterol adhere to the inner wall of the blood vessel 5. When the intravascular expansion tool 1 self-expands and physically expands the blood vessel 5, as shown in FIGS. 3C and 4B, the deposit 7 is also expanded. At this time, in the case of the conventional stent, there was a risk that a part of the deposit 7 would be released into the bloodstream through the mesh gap, but the stent was expanded using the intravascular expansion device 1 of the present embodiment. Then, the inner surface of the blood vessel 5 is covered with the base film 2 in a film state, so that the release of the deposit 7 into the bloodstream can be suppressed to a minimum. Therefore,
Occlusion of peripheral blood vessels is unlikely to occur due to the deposit 7 released.

A large number of fine holes 3 are formed in the base film 2. Therefore, after the operation, the coating of the inner wall of the intravascular expansion device 1 with the blood vessel wall cells is promoted. This will be described with reference to FIG. Immediately after the expansion operation using the intravascular expansion tool 1, the vascular wall cells (including vascular endothelial cells) 8 of the expanded blood vessel 5 simply contact the outer periphery of the base film 2 as shown in FIG. It is in the state of doing. The blood vessel wall cell 8 is a cell existing on the innermost surface side of the blood vessel 5, and the blood vessel endothelial cell contained in the blood vessel wall cell 8 plays a role of suppressing blood coagulation and preventing thrombus formation. The deposits 7 such as cholesterol accumulate under the blood vessel wall cells 8 (outer wall side of the blood vessel 5).

Then, with the lapse of time after the operation, the vascular wall cells 8 of the blood vessel 5 are gradually exuded into the inside of the base film 2 from the micropores 3 and eventually, as shown in FIG. The inside of the cell is uniformly coated with the vascular wall cells 8. That is, the large number of fine holes 3 provided in the base film 2 promotes the covering with the blood vessel wall cells 8 inside the intravascular expansion device 1. what if,
If the micropores 3 are not provided in the base film 2, the blood vessel wall structure in which the blood vessel wall cells 8 are arranged inside the intravascular expansion device 1 is not constructed, and blood coagulation occurs in the intravascular expansion device 1 after surgery. This may result in the formation of a thrombus, which may result in blockage of the blood vessel 5. However, like the intravascular expansion device 1 according to the present invention, the base film 2 has a large number of fine holes 3.
5B, the inside of the base film 2 is uniformly covered with the blood vessel wall cells 8 and the blood vessel wall cells 8 are lined up inside the intravascular expansion device 1 as shown in FIG. 5B. A blood vessel wall structure is constructed, and as a result, blood vessel coagulation is suppressed by the action of the blood vessel wall structure, and thrombus formation in the intravascular expansion device 1 is prevented.

Here, the diameter of the fine holes 3 is 30 μm or more.
The reason why it is set to 00 μm or less is as follows.
That is, if the diameter of the micropores 3 is less than 30 μm, the vascular wall cells 8 are unlikely to seep out. On the other hand, if the diameter of the micropores 3 is larger than 100 μm, not only the blood vessel wall cells 8 but also the deposits 7 such as cholesterol may be pushed into the inside of the base film 2 and released into the bloodstream. In addition, the total area of the micropores 3 is set to be 10% or more of the area of the base film 2 because when it is less than 10%, the blood vessel wall cells 8 are uniformly soaked in the entire inner surface of the base film 2. This is because it is difficult to put out.

Further, the intravascular dilation device 1 according to the present invention can be wound into a thin circular tube, and a normal catheter 4 can be used.
It is possible to guide the stenotic lesion site 6 by being installed inside.
Therefore, a large device such as a balloon catheter is not necessary for guiding.

Further, the intravascular expansion tool 1 according to the present invention is composed of the base film 2 having elastic deformability, and is remarkably rich in shape deformability as compared with the conventional metal stent. Therefore, in combination with the miniaturization of the guiding device described above, the intravascular dilation instrument 1 can be easily guided and used even for a blood vessel that is more complicated and thinner than the conventional one, for example, a blood vessel in the brain.

Furthermore, the intravascular expansion device 1 according to the present invention
If so, since the base film 2 has a large surface area, a large amount of a blood coagulation inhibitor such as heparin can be immobilized on the surface thereof. Intravascular expansion device 1 with a large amount of blood coagulation inhibitor fixed on the surface of the base film 2
If the vasodilation is performed by the method described above, the prevention of thrombus formation after surgery can be made more complete. Further, even if it is other than the blood coagulation inhibitor, if a predetermined drug is fixed on the surface of the base film 2, effective drug treatment can be used together after the operation.

The embodiments of the present invention have been described above, but the present invention is not limited to the above examples.
For example, in the above-described embodiment, as shown in FIG. 1, a large number of fine holes 3 are formed in one sheet-shaped base film 2 to form the intravascular dilatation device 1. You can In the example shown in FIG. 6, a plurality of cuts 11 parallel to each other are provided in the base film 2 having a large number of fine holes 3. Each notch 11 is provided perpendicularly to the axial direction of the base film 2 in a tubularly wound state. In other words, the base film 2 is wound up along the formation direction of the notch 11. By providing such a plurality of cuts 11, the intravascular expansion device 1 in a wound state can be bent at each cut 11. Therefore, it is possible to easily guide and use the intravascular expansion tool 1 for a blood vessel that is more complicated and thinner than the above-described embodiment.

The intravascular expansion tool 1 may be configured as shown in FIG. In the example shown in FIG. 7, a plurality of strip-shaped base films 12 are arranged in parallel to each other and a cord-shaped connecting yarn 1 is formed.
The intravascular expansion device 1 is constructed by sequentially connecting at 3. Each base film 12 has a plurality of fine holes 3
Has been drilled. The intravascular expansion device 1 of FIG. 7 is used by winding each strip-shaped base film 12 along the longitudinal direction. Even in this case, as in the case of FIG. 6, the wound intravascular expansion device 1 can be bent between the adjacent base films 12. Therefore, it is possible to easily guide and use the intravascular expansion tool 1 for a blood vessel that is more complicated and thinner than the above-described embodiment.

In the above embodiment, the base film 2 is made of polyimide, but the present invention is not limited to this, and the base film 2 is made of other high-strength polymer material having a small effect on the living body. Alternatively, it may be formed of polyester, for example. That is, the base film 2 may be formed of a material having an elastic deformability that tends to return to the original sheet shape when it is inserted into a blood vessel in a tubularly wound state.

The shape of the fine holes 3 is not limited to a circular shape, and any shape may be used as long as the maximum width of the cross section perpendicular to the forming direction of the fine holes 3 is 30 μm or more and 100 μm or less.

Further, the intravascular expansion device 1 according to the present invention has a small diameter of 2 mm or less (mainly a blood vessel in the brain).
However, it is needless to say that it can also be used for a blood vessel having a large diameter of 2 mm or more.

[0032]

As described above, according to the invention of claim 1, when a film is inserted into a blood vessel while being rolled up in a tubular shape, the elastic deformability of the film causes the film to self-expand, thereby increasing cholesterol. The blood vessel can be sufficiently expanded and maintained without releasing such substances, and since the film deforms relatively easily, the intravascular expansion device can be easily guided even for a thin blood vessel such as in the brain.

According to the second aspect of the present invention, since the cross section perpendicular to the direction of formation of the micropores is a substantially circular shape with a diameter of 30 μm or more and 100 μm or less, it is possible to suppress the release of cholesterol and the like to the inside of the intravascular expansion device. However, it is possible to construct a blood vessel wall structure on the inner surface of the intravascular expansion tool.

According to the third aspect of the invention, since the film is made of polyimide, it is possible to impart sufficient elastic deformability to the film.

Further, according to the invention of claim 4, since the film is formed of polyester, it is possible to impart sufficient elastic deformability to the film.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of an intravascular expansion tool according to the present invention.

FIG. 2 is a perspective view showing a state of a process of winding the intravascular expansion device of FIG.

3A to 3D are schematic views sequentially showing a process of guiding and placing the wound intravascular expansion device at a stenotic lesion site.

4A to 4D are cross-sectional views sequentially showing a process of guiding and placing the wound intravascular expansion device at a stenotic lesion site.

FIG. 5 is a diagram for explaining the coating with vascular wall cells inside the intravascular dilatation device after surgery.

FIG. 6 is a plan view showing another example of the intravascular expansion device according to the present invention.

FIG. 7 is a plan view showing another example of the intravascular expansion device according to the present invention.

[Explanation of symbols]

1 Intravascular expansion tool 2,12 base film 3 fine holes 4 catheter 5 blood vessels 6 Stenotic lesions 7 deposits 8 Blood vessel wall cells

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Susumu Yamada             4-chome Tenjin, which runs up to Teranouchi, Horikawa-dori, Kamigyo-ku, Kyoto             1 Kitamachi No. 1 Dai Nippon Screen Manufacturing Co., Ltd.             Inside the company (72) Inventor Shuichi Araki             4-chome Tenjin, which runs up to Teranouchi, Horikawa-dori, Kamigyo-ku, Kyoto             1 Kitamachi No. 1 Dai Nippon Screen Manufacturing Co., Ltd.             Inside the company F term (reference) 4C167 AA58 BB07 BB12 BB26 BB37                       CC09 DD01 EE03 GG08 GG09                       GG31 GG46 HH08

Claims (4)

[Claims] 1. An intravascular expansion tool for expanding the blood vessel by inserting the blood vessel into the blood vessel, which is formed of a film having elastic deformability and having a plurality of fine holes formed therein, and is wound up. An intravascular expansion tool characterized by expanding the blood vessel by a deployment force based on the elastic deformability when the blood vessel is inserted in a state. 2. The intravascular expansion device according to claim 1, wherein the cross section perpendicular to the direction of forming the micropores is 30 μm or more and 1
An intravascular dilation device characterized by having a substantially circular shape with a diameter of 00 μm or less. 3. The intravascular expansion device according to claim 1 or 2, wherein the film is made of polyimide. 4. The intravascular expansion device according to claim 1 or 2, wherein the film is made of polyester.