JPH021296A - Medical shape memory alloy parts and catheters - Google Patents

Abstract

PURPOSE:To sufficiently and certainly perform the treatment of a constriction part and other prosthesis to prevent re-constriction by using a member having a property not generating a dimensional change in a longitudinal direction and generating a diameter change before and after deformation and providing an opening to the side surface thereof. CONSTITUTION:After a catheter is inserted in a blood vessel 13 up to the position of a constriction part 14, a balloon 3 is expanded by feeding a physiological saline solution 4 in said balloon 3 to be closely brought into contact with the inner wall of the blood vessel and the flow of blood or body fluids is temporarily stopped. The catheter main body 2 is moved forwardly by a guide wire 6 so that a cylindrical body 8A is exposed from a sheath 9. The heated physiological solution 4 passes through the sheath 9 (the outer periphery of the catheter main body) from an introducing port 11 to be led out toward the cylindrical body 8A and heats the cylindrical body 8A made of a shape memory alloy to change the same to the original expanded shape thereof. Since the cylindrical body 8A has a part 8Ab continuous in the longitudinal direction, there is no dimensional change in the longitudinal direction. Therefore, the entire region of the constriction part 14 can be easily and certainly expanded by the cylindrical body 8A. The physiological saline solution in the balloon 3 is drained and the balloon 3 is contracted to pull out the catheter.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to medical shape memory alloy members and catheters, and particularly to medical shape memory alloy members and catheters. The present invention relates to a medical shaped alloy member used for expansion, and a catheter equipped with the same.

Conventionally, for the treatment of angina pectoris or myocardial infarction, for example, a catheter called a PTCA (percutaneous coronary artery reconstruction) catheter is inserted into a narrowed part of the coronary artery of a living heart. There is. That is, as a treatment for lesions associated with coronary artery stenosis, in addition to treatments using thrombolytic agents and the like, there is a method of mechanically dilating the stenosis using a PTCA catheter.

These catheters generally have a plastic or rubber balloon at their tip, and after being inserted into the stenosis, the balloon is inflated, and this balloon expansion presses and dilates the stenosis, after which a surgical procedure is performed in which the catheter is removed. It is being said. Although this method is relatively easy to treat, it has the disadvantage that the effect is not permanent and the tissue tends to return to its original shape over time, causing stenosis again.

As a method to improve this drawback, a device has been proposed in which a cylindrical body made of a shape memory alloy is embedded within a blood vessel (however, the implanted cylindrical body is then covered with living tissue). See, for example, U.S. Pat. No. 3,868, . There are No. 956 and Special Publication No. 61-6655. The former involves storing a pre-expanded state, inserting a shape-memory alloy cylindrical body with a narrow diameter through a catheter, heating it electrically, returning it to its original shape, and expanding the blood vessel. In the latter method, a shape memory alloy plate is molded into a cylindrical shape with the normal inner diameter of the blood vessel, processed into a thinner diameter, inserted into the desired position of the blood vessel via a catheter, and then exposed to laser beams or high-frequency waves. It is heated using induction heating to return it to its original shape.

However, in the former device, the shape memory alloy cylindrical body is heated by another heating element or by an electric method using the electric resistance of the shape memory alloy, so there is a risk of electrical leakage and electric shock. There is a danger that this will occur, and the equipment will also be complicated.

Furthermore, in the latter method, a laser beam or high frequency induction heating device used in place of the former electric heating method is not disclosed, but it is complicated and expensive.

In addition to the blood vessels mentioned above, similar medical procedures are also performed on the trachea and bronchi. For example, if the bronchial tubes are compressed and narrowed due to lung cancer, etc., to ensure breathing, the trachea is incised on the lung side of the vocal cords and a catheter is inserted, or an endotracheal catheter is inserted through the pharynx. . That is, as a treatment for lesions accompanied by stenosis of the bronchi and trachea, a method of mechanically securing the airway using these catheters is generally adopted.

However, since the former catheter is inserted through an incision in the bronchus, the patient cannot make a sound after insertion, which is an unfavorable situation for a conscious patient. First, there is a drawback that the catheter can only be left in place for one week if the patient is awake and the foreign body sensation is significant.

BACKGROUND OF THE INVENTION Therefore, the present applicant has already proposed in Japanese Patent Application No. 62-97437 a catheter that can realize a method of dilating a stenotic area that is easy to operate and very safe to perform, without relying on the above-mentioned method. did. This catheter has a blocking part (e.g., a balloon) at its distal end that has the function of arbitrarily blocking the flow of blood vessels and/or body fluids by manipulation from outside the body, and the latter of the blocking part is fitted onto the catheter. A cylindrical unit made of a shape memory alloy that restores to a pre-memorized shape above the transition temperature,
The shape memory alloy cylindrical body portion is characterized by having a supply means for supplying a warming liquid to the outer peripheral portion of the catheter. That is, a shape memory alloy cylindrical body that has been memorized in advance to have a desired original shape and has been machined into a small diameter is heated with a heated liquid to return to the original shape.

However, as a result of further study of the catheter according to the above-mentioned prior application, the present inventor found that although the above-mentioned excellent effects were achieved, there were still points to be improved.

FIG. 26 shows a shape memory alloy coil inserted into a narrowed part of a coronary artery using the catheter described in the above-mentioned Japanese Patent Application No. 62-97437, and the said narrowed part returned to its original shape by the returning action of the coil. The state in which the coil is about to be restored is shown, with (A) showing the coil before it returns to its original shape, and (B) showing the state where the coil is about to return to its original shape.

A heating fluid is sent into the coronary artery 13 through the pores provided in the catheter and the opening thereof, and the shape memory alloy coil 68 is heated to its original shape recovery temperature (transition temperature) or higher to expand the coil 68. The diameter of the coil 68 increases, and the circumferential constricted portion 14 is pushed out, but the pitch of the coil 68 does not change when the diameter is expanded, and therefore the length becomes smaller. Therefore, coil 6
If the central position of the coil 68 is slightly off from the central position of the stenotic part 14, or if one end of the coil contacts the blood vessel 13 first, the coil 68 may expand the entire area of the stenotic part 14. 26 (B), the stenotic part 1
In some cases, a problem arises in that part (sometimes all) of 4 remains narrowed.

20 Purpose of the Invention The present invention has been made in view of the above circumstances, and includes:
The object of the present invention is to provide a medical shape memory alloy member and a catheter using the same, which can sufficiently and reliably perform treatment (especially dilation) and other repair of stenotic areas and prevent restenosis.

Structure of the Invention The first invention of the present invention is a medical shape memory device having a property that there is substantially no change in dimensions in the longitudinal direction and a change in diameter before and after deformation, and an opening is provided on the side surface. Pertains to alloy members.

A second aspect of the present invention is a catheter equipped with a shape memory alloy member, wherein the shape memory alloy member has a property that there is substantially no change in dimension in the longitudinal direction and the diameter changes before and after deformation, The present invention relates to a catheter characterized in that an opening is provided on the side surface.

To, Example The present invention will be explained in detail below.

1 to 4 show an example of the catheter of the present invention.

The PTCA catheter 1 according to this example includes polyethylene,
It has a catheter body 2 made of vinyl chloride, silicone rubber, polyurethane elastomer, etc., and a balloon 3 made of elastic rubber or plastic is provided at the tip of this body, and a physiological saline solution 4 is sent to (or discharged from) the balloon 3. )
A lumen 5 is embedded along the length of the main body. Further, a lumen 7 for passing the guide wire 6 is formed in the center of the main body 2, penetrating from the rear end to the front end. Further, at a slightly rearward position of the balloon 3, for example, a Ni-T film with a large number of through holes 8Aa formed on the side surface is placed.
A shape memory alloy cylindrical body 8A made of a rolled i-alloy plate is attached. In this catheter, the main body 2 is almost entirely covered with a sheath 9 made of polyurethane elastomer, for example, except for the balloon 3.
At the rear end side of the sheath 9 is an inlet 11 for injecting the warming liquid 10.
are set up in a branched manner.

In the above, the cylindrical body 8A has a transition temperature of its alloy (A3
It has the property of restoring, that is, expanding, to a pre-memorized shape at a temperature above the transformation point. Since these shape memory alloys are inserted into living organisms, their transition temperature is 3" higher than body temperature.
C level or higher (especially 38°C to 48°C)
°C), and such a transition temperature can be obtained by appropriately selecting the alloy composition of the shape memory alloy. Also,
From the inlet 11 of the sheath 9, a warming liquid 10 is supplied to the cylindrical body 8A through between the catheter body 2 and the inner surface of the sheath 9. Such warming liquid may include infusion fluid, physiological saline, etc. can be used, and the temperature of the liquid is:
The temperature is chosen at a level that does not cause burns, taking into account that the temperature will drop due to mixing with blood and body fluids at the insertion site.

The cylindrical body 8A is a plate whose shape is memorized to a desired expanded diameter after being heated in advance, and then re-wound into a thin cylindrical shape and attached to the outer circumference of the catheter. The outer diameter of that portion of the catheter 2a is small to prevent it from sliding along the walls. Of course, instead of reducing the external size of this portion, an annular stopper made of silicone rubber or the like may be attached to the catheter.

What should be noted in this example is that the cylindrical body 8A is
As shown in FIG.
- A Ti alloy (50 atomic% Ni) plate was made into a cylinder shape, and in this state was heat treated for shape memory by heating at 400 to 500°C for 20 to 40 minutes, and then as shown in Figure 6 (A). It is then re-rolled and molded into a small-diameter cylindrical body.

The catheter 1 configured as described above is inserted, for example, from the femoral artery 15 into the coronary artery 13 of the living heart 12 from the balloon 3 side, as shown in FIG. (This is only a schematic representation of the enlarged state.) At this time, the catheter main body 2 is guided to a predetermined site by the sheath 9, and this guidance is effectively achieved by the above-mentioned guide wire 6. Further, this guidance can be monitored by observing the catheter and the alloy cylindrical body 8A with an X-ray imaging device.

After inserting the catheter to the position of the stenosis 14 of the blood vessel 13 as shown in FIG. 5(A), as shown in FIG. 5(Sun), the balloon 3 is inflated by supplying physiological saline 4 to It is placed in close contact with the inner wall to temporarily stop the flow of blood or body fluids. At this time, the catheter main body 2 is moved forward by the guide wire 6 so that the cylindrical body 8A is exposed from the sheath 9, as shown in FIG. 5(A).

Next, as shown in FIG. 5(C), the introduction port 11 of the sheath 9 is opened.
Physiological saline 4 is supplied at a constant temperature of, for example, 50°C. The heated physiological saline 4 is introduced into the sheath 9 (outer periphery of the catheter body) from the introduction port 11 as shown in FIG.
It passes through and is led out to the cylindrical body 8A side. The temperature of the derived physiological saline initially decreases as it mixes with blood, etc., but gradually rises, heating the cylindrical body 8A above the transition point, and forming an expanded shape of the original shape (Fig. 5 (C) ) is shown as a solid line, and shown as a virtual line in FIG. 4). In this state, the cylindrical body 8A has returned to its original shape as shown in FIG. 6 (Sun).

In this way, the cylindrical body 8A transitions from the shape shown in FIG. 6(A) to the shape shown in FIG. 6(B), but this shape memory alloy member (cylindrical body 8A) is not coiled ( , has the portion 8Ab continuous in the longitudinal direction, so the dimension in the longitudinal direction does not substantially change.

Therefore, as in the case of using the shape memory alloy coil 68 as explained in FIG. Therefore, the entire area of the narrowed portion 14 can be easily and reliably expanded with the cylindrical body 8A as shown in FIG. 5(C).

Next, the physiological saline in the balloon 3 is drained, the balloon 3 is deflated, and the catheter is removed as shown in FIG. 5(D).

In this way, the cylindrical body 8A is placed in the blood vessel with the narrowed portion 14 expanded, and the purpose of treatment can be achieved.

As described above, according to the catheter 1 of the present embodiment, it is possible to easily and reliably dilate the narrowed part of the blood vessel and reliably prevent the restenosis, and the heating liquid for deforming the cylindrical body can be transferred to the catheter. Since the supply is not through the inside of the main body, but through the sheath around the outside, a sufficiently large passage can be ensured, allowing use at lower temperatures. Therefore, the operation is safe, rapid injection is possible, and the catheter body itself can be made thin (no lumen for warm fluid is required), making it easy to insert into small blood vessels such as coronary arteries. Furthermore, the use of a sheath facilitates insertion of the catheter, and the insertion operation can be performed reliably.

The numerous through-holes 8Aa of the cylindrical body 8A expose the inner circumferential surface of the blood vessel 13 so that endothelial tissue is generated, thereby allowing the cylindrical body 8A to be embedded within the blood vessel 13 for a long period of time. This has the effect of sustaining the dilation of the stenosis in a hygienic manner over a period of time.

The cylindrical body 8A has a large number of linear rows of through holes 8Aa in the longitudinal direction, and a continuous part 8Ab in the longitudinal direction is formed in a straight line. It is sufficient to substantially prevent the change; therefore, the through holes may be arranged, for example, in a staggered manner to form a substantially continuous portion in the longitudinal direction (meandering continuous portion).

In addition, as shown in FIGS. 7(A) and (Sun), a large number of slits 8 are left on both edges of the shape memory alloy cylindrical body on the 8th day.
A continuous portion in the longitudinal direction may be formed on both edges without slits.

In addition, as shown in FIGS. 8(A) and (Sun), a large number of slits 8Ca are provided on both sides from the circumferential center of the shape memory alloy cylindrical body 8C to form a rib shape, and a longitudinal A continuous portion 8Cb in the direction may be formed. 7th
In both Fig. 8 and Fig. 8, (A) shows the shape before returning to its original shape, and (B
) indicates the shape after returning to its original shape.

9 to 13 respectively show other shape memory alloy cylindrical bodies, and all show the shape after returning to the original shape.

The cylindrical body 8D in FIG. 9 has a plurality of sulins l-8 in the longitudinal direction.
Da and a continuous portion 8Db in the longitudinal direction are formed.

The cylindrical body 8E in FIG. 10 is a shape memory alloy wire 8 in the longitudinal direction.
A mesh-like cylindrical body is formed by weaving Eb and a shape memory alloy wire 8Ec perpendicular to the entwined wires.

A large number of openings (through holes) 8 are formed by the line 8Eb and the line 8Ec.
Ea is formed.

The cylindrical body 8F in FIG. 11 has shape memory alloy wires 8Fb, 8Fb inclined at 45° and 135° in the longitudinal direction and orthogonal to each other.
It is woven into a mesh-like cylindrical body.

A staggered continuous portion is formed in the longitudinal direction by the lines 8Fb, 8Fb, and a large number of openings (through holes) 8Fa are formed.

The cylindrical body 8G in FIG. 12 has a truncated conical shape in its original form, and has a plurality of through holes 8Ga arranged in stages, and a continuous portion 8Gb in the longitudinal direction.

The cylindrical body 8H in FIG. 13 has a small diameter portion 8Hc in its original shape.
, a large diameter portion 8He, and a tapered connecting portion 8 that connects both.
It is made of Hd, has a large number of through holes 8Ha, and has a continuous portion 8Hb formed in the longitudinal direction.

The catheter assembled with the cylindrical body shown in Figs. 6 to 11 can be inserted percutaneously from the femoral artery or other parts, and can be used to treat obstructive arteriosclerosis, arteriovenous disease, and the trachea or bronchus as described below. It is particularly effective for A catheter assembled with the cylindrical body shown in FIGS. 12 and 13 is particularly effective for treating locations where the diameter of a blood vessel changes, such as a branch of a blood vessel, or a connection between a trachea and a bronchus, which will be described later.

In addition to the structures shown in FIGS. 1 to 3, the catheter can have a structure shown in an enlarged plan view in FIG. 15 and in an enlarged sectional view in FIG. 16. Note that FIG. 16 is an enlarged image in the vertical direction. This catheter can be inserted into the trachea or bronchi in addition to being inserted into the blood vessels as described above.

This catheter 21 is provided with a balloon 23 at its tip, and a lumen 25 for sending (or discharging) air 24 or physiological saline 4 into the balloon 23 is formed by being embedded along the length direction of the main body. There is. In addition, a lumen 27 is formed in the center of the main body 22 to pass through the guide wire (not shown) and to ensure breathing from the rear end to the front end. Furthermore, a hot water injection lumen 29 for restoring the shape memory alloy to its original shape is embedded along the length of the balloon body from slightly behind the balloon 23 to its tip. The main body 22 has a balloon 23
A small-diameter portion 22a having a small outer diameter is provided at a slightly rearward position, and a cylindrical body 28 made of a shape memory alloy is attached to the small-diameter portion 22a.

The cylindrical body 28 has a similar shape to the cylindrical body 8A shown in FIG.
b is formed, and as shown in FIG. 17, which is a mostly cross-sectional view taken along the line X■-X■ in FIG.
A coating layer 28d made of a flexible material is applied to the surface of the thin plate 28c of the shape memory alloy by, for example, dipping. As the material for the coating layer 28d, for example, an inert polymer such as Teflon, an antithrombotic polymer such as cardiosan, a polymer capable of sustained release of drugs such as heparin and urokinase, etc. are used. When inserting the catheter into a lumen such as the trachea, bronchus, biliary tract, or esophagus, the material for the coating layer 28d may be porous polytetrafluoroethylene, silicone, polyurethane, natural rubber, chlorohydrin rubber, or fluorinated rubber. In addition to those having elasticity, polyester woven fabrics or knitted fabrics can be preferably used.

FIGS. 18(A) to 18(E) show a procedure for treating a bronchial stenosis using the catheter shown in FIGS. 15 to 17, and each shows only the bronchus 43 in cross section.

First, the catheter 21 is inserted just before the constricted part 44 of the bronchus 43.
Insert. At this time, the rear end step portion 2 of the main body small diameter portion 22a
2b functions as a stopper to prevent the cylindrical body 28 from coming off the small diameter portion 22a and remaining behind (FIG. 18(A))
.

Next, the balloon 23 is inflated with air 24 or physiological saline 4, etc., and the inflated balloon 23 is repeatedly moved back and forth in the constriction part 44 to expand the constriction part 44 (18th
Figure (B)).

Next, the catheter 21 is advanced to position the cylindrical body 28 within the constriction 44, and the air 24 or physiological saline 4
and deflate the balloon 23 (Fig. 18(C)).
.

Next, the balloon 23 is inflated again to bring it into close contact with the inner surface of the bronchus 43, so that the warm water to be injected next does not flow out toward the lungs. Subsequently, hot water 1o is injected into the hot water outlet 2.
When supplied from 9a to the cylindrical body 28, the shape memory alloy thin plate 28c of the cylindrical body 28 returns to its original shape as the temperature rises above the transition temperature, expands the diameter, and expands the narrowed portion 44 (Fig. 18(D) )
).

Next, pour the hot water 10 into the hot water injection lumen (29 in Figure 16).
) to prevent hot water from entering the lungs, deflate the balloon 23, and remove the catheter body 22.
Remove. Thus, since the coating layer 28d in FIG. 18 is made of a flexible material, it does not interfere with the return of the cylindrical body 28 to its original shape.

A flexible coating layer 28d is formed on the surface of the cylindrical body 28, and as shown in FIG. 17, the ridges are rounded by the coating, so that organs such as the bronchi are not injured. Since the coating layer 28d is made of a material that does not have an adverse effect on living organisms, it is mechanically and chemically safer. Further, by providing the coating layer 28d, the surface roughness of the shape memory alloy material 28c is not a problem, and surface finishing can be omitted, thereby reducing the manufacturing cost.

In addition, in the treatment of blood vessels, the coating layer 2 is made of the above-mentioned material.
8d, in addition to the above-mentioned safety, thrombus formation is prevented. Further, by covering the cylindrical body 28 with a flexible material, it is easier to make the surface uneven in order to improve the indwelling property of the cylindrical body 28.

Figure 20 shows body temperature or lower (e.g. around 30°C)
This figure shows a catheter assembled with a cylindrical body of a shape memory alloy that has a transition temperature of , and exhibits superelasticity above the transition temperature.

Superelasticity refers to a phenomenon in which strain increases significantly even when stress increases only slightly. Figure 19 shows Ti− with 50 atom% Ni.
It is a graph showing the relationship between strain and tensile stress in a tensile test in a state where the Ni alloy wire has returned to its original shape. Note that the above original shape is a straight line. In a range of small distortion, the relationship between the two is shown as a straight line according to Hooke's law. After the strain reaches a predetermined value, the strain increases even if the increase in stress is small, as shown in A. This phenomenon is called superelasticity, and is a phenomenon observed when a Ti-Ni alloy of a predetermined composition is subjected to a predetermined heat treatment.

The main body 32 of the catheter 31 in FIG. 20 has a small diameter portion 32a formed in contact with the rear end of the balloon 33 at the tip, and a lumen 35 for supplying air 24 (or physiological saline 4) to the balloon 33. There is. Further, a lumen 37 for passing a guide wire (not shown) and for ensuring breathing is provided in the center of the main body along the length direction of the main body. A cylindrical body 38 made of a shape memory alloy is fitted onto the small diameter portion 32a, and three pairs of rings 38c, 38c, 38c, 38c, 38c are provided on the cylindrical body 38.

A fixing wire 36 is inserted through 38c. Further, the tip of the fixing wire is made slightly larger to prevent the ring 38C from coming off.

FIG. 21 shows the cylindrical body 38, with FIG. 21(A) showing the shape before restoration to the original shape, and FIG. 21(B) showing the shape after restoration to the original shape. The cylindrical body 38 has substantially the same structure as the cylindrical body 28 shown in FIGS. 15 to 17, and is formed with a large number of through holes 38a and a continuous portion 38b in the longitudinal direction. Pairs of rings 38c are provided at both ends in the longitudinal direction and at or near the center, and before restoration to the original shape (FIG. 21(A)), pairs of rings 38c are provided at both ends and the center, respectively. , 38c overlap each other, and the fixing wire 3 in FIG.
6 can be inserted.

22(A) to (E) show a procedure for treating a bronchial stenosis using the catheter shown in FIG. 20, and each shows only the bronchus 43 in cross section.

First, the catheter 31 is inserted just before the constricted part 44 of the bronchus 43.
Insert. At this time, the cylindrical body 38 has already reached the transition temperature due to body temperature and attempts to return to its original shape and expand its diameter. The shape shown in Fig. 21 (A) is maintained. Rear end stepped portion 32b of main body small diameter portion 32a
functions as a stopper to prevent the cylindrical body 38 from coming off the small diameter portion 32a and remaining behind during insertion (see FIG.
)).

Next, the balloon 33 is inflated with air 24 or physiological saline 4, etc., and the inflated balloon 33 is repeatedly moved back and forth in the constriction part 44 to expand the constriction part 44 (22nd
Figure (B)).

Next, the catheter 31 is advanced to position the cylindrical body 38 within the narrowed part 44, and the air 24 or physiological saline 4
and deflate the balloon 33 (Fig. 22(C)).
.

Next, the balloon 33 is inflated again to bring it into close contact with the inner surface of the bronchus 43, the catheter body 32 is fixed to the bronchus 43, and the fixing wire 36 is pulled out from the ring 38c. At this time, the rear end step portion 32b of the small diameter portion 32a functions as a stopper that prevents the cylindrical body 38 from moving rearward together with the wire 36. When the wire 36 is removed, the cylindrical body 38 becomes free and returns to its original shape, expands in diameter, and closes the narrowed part 4.
4 (Fig. 22(D)).

Next, the balloon 33 is deflated and the catheter body 32 is pulled out. Thus, as shown in FIG. 22(E), the cylindrical body 38 with the narrowed part 44 expanded is placed in the bronchus 43,
Treatment ends.

Note that the fixing wire 36 can also be used as a guide wire when inserting the catheter 31. If a straight wire made of a shape memory alloy that exhibits superelasticity is used for this wire, it will easily deform to follow the curves of the trachea or blood vessels, and immediately return to its original shape in the straight parts. Therefore, it can be inserted extremely easily and can be used very conveniently as a guide wire.

The cylindrical body 38 in FIG. 21 is provided with six rings 38c facing outward, so that these rings dig into the wall of the bronchus after treatment. The cylindrical body 48 shown in FIG. 23 is provided with rings 48c on its inner peripheral side to prevent these rings from digging into the bronchial tube wall. Same figure (
A) shows the shape before restoration to its original shape, and (B) shows the shape after restoration to its original shape. In the figure, 48a is a through hole, and 48b is a continuous portion in the longitudinal direction. In other respects, there is no difference from the cylindrical body 38 in FIG. 21.

The cylindrical body 48 in FIG. 23 is provided with a ring 48c facing inward. In this case, Fig. 24 is an enlarged internal plan view, and Fig. 25 is an enlarged sectional view (xxv-xxv in Fig. 24).
As shown in FIG.
It is preferable that a bridge portion formed so as to protrude slightly inwardly between the rings e is used as a ring support portion 58f, and the ring 58c is swingably supported by this. blood is blood vessel 13
by flowing as shown by the arrow within the ring 58c.
The ring 58c falls down substantially along the flow of blood, which is advantageous because the disturbance in blood circulation caused by the ring 58c is reduced.

Although the present invention has been illustrated above, the above-mentioned example can be further modified based on the technical idea of the present invention.

For example, the composition, material, shape, etc. of the above-mentioned shape memory alloy may be changed in various ways. As for the material, it is preferable to use a material that does not return to its original shape after being transferred to its original shape (irreversible transition), as in the above example, but the shape of the transition can be selected from various types. Furthermore, depending on the purpose of use, the transition may be reversible (it shrinks when cooled).

Further, 1. The mounting position and pattern of the shape memory alloy are not limited to those described above. The catheter of the present invention can be inserted not only into the narrowed areas of blood vessels, tracheas, or bronchi as described above, but also into areas where these organs have become thin and are likely to rupture (and may be inserted into other areas). Good too.

As described in detail, the present invention provides that the shape memory alloy member does not substantially change in dimension in the longitudinal direction before and after deformation, so that the shape memory alloy member can be applied to the treated part of the living body such as a blood vessel during deformation. The member can be accurately positioned and brought into contact without fear of dislodging from the treatment area. Moreover, this operation is easy. Furthermore, since the shape memory alloy member has an opening on the side, endothelial tissue is generated from the living body part exposed through this opening, and the shape memory alloy member is embedded in the living body and forms a part of the living body to be treated. Recurrence of defects (for example, restenosis of blood vessels, etc.) is reliably prevented over a long period of time.

[Brief explanation of the drawing]

1 to 25 show embodiments of the present invention, in which FIG. 1 is a perspective view of the catheter, FIG. 2 is a sectional view of the catheter body, FIG. 3 is a perspective view of the sheath, and FIG. The figure is a cross-sectional view of the catheter showing the transition state of the shape memory alloy coil. Figures 5 (A), 5 (B), 5 (C), and 5 (D) are the catheter inserted into the blood vessel. 6 shows a shape memory alloy cylindrical body, FIG. 6 is a perspective view after returning, and FIG. 7 is another example. The figure (A) is a perspective view before returning to the original shape, the figure (B) is a perspective view after returning to the original shape, and FIG. 8 is a shape memory alloy tube according to another example. It shows the shape of the body,
Figure (A) is a perspective view before returning to its original shape, Figure (B) is a perspective view after returning to its original shape, and Figures 9, 10, 11, 12, and 13 are further illustrations. FIG. 14 is a schematic view of a catheter inserted into a coronary artery; FIG. 15 is a plan view of a catheter according to another example; FIG. 16 is a similar diagram. 17 is an enlarged partial sectional view of the shape memory alloy cylindrical body used in the catheter of FIGS. 15 and 16; FIG. 18 (A)
, FIG. 18(B), FIG. 18(C), FIG. 18(D), and FIG. 18(E) are partial cross-sectional views sequentially showing the operation of inserting a catheter into the bronchus and treating the stenosis. , Figure 21 shows the shape memory alloy cylindrical body used in the catheter of Figure 20, the same figure (A) is a perspective view before returning to its original shape, the same figure (Japanese) is a perspective view after returning to its original shape, Figure 22 (A), Figure 22 (B), Figure 22 (C), Figure 22 (D) and Figure 22 (E) show the catheter shown in Figure 20 being inserted into the bronchus to remove the narrowed area. Each partial sectional view sequentially showing the treatment operations, FIG. 23 shows a shape memory alloy cylindrical body according to another example, and FIG. 23 (A) is a perspective view before returning to its original shape.
FIG. 24 is an enlarged internal partial plan view of another example of a shape memory alloy cylindrical body used in a blood vessel, and FIG. 25 is a perspective view after returning to its original shape. It is a sectional view taken along the line xxv. FIG. 26(A) and FIG. 26(E3) are enlarged cross-sectional views showing the state of transfer of a shape memory alloy coil within a blood vessel using a conventional catheter. In addition, in the symbols shown in the drawings, 1.21.31... Catheter 2.22
．． 32... Catheter body 3.23.3
3...Balloon 4...Physiological saline 6...Guide wires 8A, 8B, 8C, 80, 8E, 8F, 8G, 8H, 2
8, 38, 48, 58... Shape memory alloy cylindrical body 8Ea, 8Fa
, 8Ga, 8Ha. 38a, 48a, 58a......Through hole 8C
a, 8Da...Slit 8Bb, 8Cb
, 8Db, 8Gb. 28b, 38b, 48b, 58b...Continuous portion 8Aa, 28a. Day 8a, 8Ab. 8Hb, 8Eb, 8Ec, 8Fb...Shape memory alloy wire 9...Sheath 10...Heating liquid 13... ... Coronary artery (blood vessel) 14.44.
...... Stricture section 24 ... Air

Claims (1)

[Scope of Claims] 1. A shape memory alloy member for medical use, which has a property that there is substantially no change in dimensions in the longitudinal direction and a change in diameter before and after deformation, and an opening is provided on the side surface. 2. The medical shape memory alloy member according to claim 1, the surface of which is covered with a flexible material. 3. The medical shape memory alloy member according to claim 1 or 2, which is provided with deformation prevention means for temporarily inhibiting deformation. 4. In a catheter equipped with a shape memory alloy member,
A catheter characterized in that the shape memory alloy member has a property that there is substantially no change in dimensions in the longitudinal direction and a change in diameter before and after deformation, and an opening is provided on the side surface. 5. The catheter according to claim 4, wherein the surface of the shape memory alloy member is coated with a flexible material. 6. The fourth aspect of claim 4, wherein the shape memory alloy member is provided with deformation prevention means for temporarily preventing deformation.
The catheter according to item 1 or 5.