JP2726696B2 - Biological dilator and catheter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a living organ dilator and a catheter, and particularly to a living organ dilator used for permanently expanding a stenotic part of an organ such as a blood vessel, a trachea, or a bronchus. And a catheter having the same.

B. 2. Description of the Related Art Conventionally, for the treatment of angina pectoris and myocardial infarction, for example, a catheter called a PTCA (percutaneous coronary artery reconstruction) catheter is sometimes inserted into a stenotic part of a coronary artery of a living heart. . That is, as a treatment for a lesion associated with stenosis of a coronary artery, there is a method of mechanically dilating a stenotic portion using a PTCA catheter, in addition to a treatment with a thrombolytic agent or the like.

Such catheters generally have a plastic or rubber balloon at the distal end, inflate the balloon after insertion into the stenosis, and inflate the balloon to press and expand the stenosis and remove the catheter after surgery. Have been done. Although the procedure of this method is relatively easy, it has the disadvantage that the effect is not durable and the tissue tends to return over time and stenosis again.

As a method for remedying this drawback, a device has been proposed in which a tubular body made of a shape memory alloy is implanted in a blood vessel (however, the implanted tubular body is subsequently covered with a living tissue). For example, U.S. Patent No. 3,868,956 and JP-B-61-6-6
There is 655. Among them, the former is to insert a cylindrical body made of a shape memory alloy having a reduced diameter by storing the expanded state in advance through a catheter, heating by an electric method, returning to the original shape, and expanding the blood vessel. It is. In the latter, a shape memory alloy plate is formed into a cylindrical shape and stored in a normal blood vessel inner diameter, processed into a small diameter, inserted into a desired position of the blood vessel via a catheter, and then heated by a laser beam or a high-frequency induction heating method. Then, the original shape is restored.

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 that there is a risk of electric leakage or electric shock. There is a danger and the equipment is complicated. Further, in the latter, a laser beam or a high-frequency induction heating apparatus used in place of the former electric heating method is not disclosed, but it becomes complicated and expensive.

Similar medical procedures are performed on the trachea and bronchi in addition to the blood vessels described above. For example, when the bronchus is compressed due to lung cancer or the like and the bronchus is constricted, in order to secure respiration, a trachea is opened at the lung side of the vocal cords and a catheter is inserted, or an intratracheal catheter is inserted via the pharynx. That is, as a treatment for a lesion involving bronchial or tracheal stenosis, a method of mechanically establishing an airway with these catheters is generally adopted.

However, since the former catheter is inserted by incising the bronchus, the patient does not produce a voice after insertion and is in an undesirable situation for conscious patients, and the latter catheter can not produce a voice as above Without noticeable foreign body sensation
The disadvantage is that if the patient is awake, the indwelling of the catheter is limited to one week.

C. Therefore, the present applicant has already proposed, as a Japanese Patent Application No. 62-97437, a catheter which can realize a dilatation method for a stenotic part which is easy to operate and which is very safe to perform, without using the above method. This catheter has a blocking portion (e.g., a balloon) having a function of arbitrarily blocking the flow of blood vessels and / or bodily fluids by operation from outside the living body at the distal end, and the catheter is externally fitted to the latter with the blocking portion. A shape memory alloy cylindrical body for restoring to a shape stored in advance at a transition temperature or higher, and a supply unit for supplying a heating liquid to an outer peripheral portion of the catheter at the shape memory alloy cylindrical body portion. Is what you do. That is, the desired original shape is stored in advance, and the shape memory alloy cylindrical body processed into a small diameter is heated by the heated liquid,
It is to return to the original shape.

However, as a result of further studies by the present inventors on the catheter according to the above-mentioned prior application, it was found that although the above-mentioned excellent effects were exhibited, there was still a point to be improved.

FIG. 25 is a diagram showing a spiral tubular body (hereinafter referred to as a coil) in which a shape memory alloy wire is spirally wound around a stenotic portion of a coronary artery using the catheter described in Japanese Patent Application No. 62-97437. ) Is inserted, and the stenotic portion is to be restored to the original shape by the original shape returning action of the coil.
FIG. 3A shows a state before the coil is returned to its original shape, and FIG. 3B shows a state where the coil is about to return to its original state.

The heating fluid is fed into the coronary artery 13 through the pores and openings provided in the catheter, and the shape memory alloy coil
The temperature of the coil 88 is raised above its original temperature (transition temperature) to expand the coil 88 and to expand the constricted portion 14 around the coil 88. However, the pitch of the coil 88 does not change when the diameter is expanded. ,
Therefore, the length is reduced. Therefore, if the position of the center of the coil 88 is slightly deviated from the center of the stenosis 14, or if one end of the coil comes into contact with the blood vessel 13 first, the coil 88 will cover the entire area of the stenosis 14. In some cases, the stenosis 14 cannot be expanded, and there is a problem that a part (sometimes all) of the stenosis part 14 remains stenotic as shown in FIG. 25 (B).

D. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and can sufficiently and reliably perform processing (especially expansion) of a stenosis portion and other prostheses, can prevent restenosis and the like, and operate the stenosis portion. It is an object of the present invention to provide a living organ dilator having good properties and a catheter using the same.

E. Constitution of the invention The first invention is characterized in that a plurality of ring-shaped parts are located apart from each other, and free ends for disconnecting the respective circumferential directions of these ring-shaped parts are formed in the ring-shaped parts, These ring-shaped portions adjacent to each other are connected by a connecting portion along the longitudinal direction of the living organ dilator, and at least the ring-shaped portion is formed of a linear body of a shape memory alloy.

According to a second aspect of the present invention, in a catheter equipped with a living organ dilator, a plurality of ring-shaped portions of the living organ dilator are located apart from each other, and the respective circumferential directions of these ring-shaped portions are disconnected. A free end is formed in the ring-shaped part, these ring-shaped parts adjacent to each other are connected by a connecting part along the longitudinal direction of the living organ dilator, and at least the ring-shaped part is a linear body of a shape memory alloy. The present invention relates to a catheter comprising:

F. Examples Hereinafter, examples of the present invention will be described.

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

The PTCA catheter 1 according to this example has a catheter body 2 made of polyethylene, vinyl chloride, silicone rubber, polyurethane elastomer, or the like, and a balloon 3 made of elastic rubber or plastic is provided at the tip of the body. A lumen 5 for sending (or discharging) the physiological saline 4 is formed by being buried along the length direction of the main body. A lumen 7 for passing a guide wire 6 is formed in the center of the main body 2 so as to penetrate from the rear end to the front end. Further, a living organ dilator (hereinafter simply referred to as dilator) 8 formed by winding a Ni-Ti shape memory alloy wire is attached to a position slightly behind the balloon 3. The catheter 2 has a sheath 9 made of, for example, polyurethane elastomer, except for a portion of the balloon 3, and the entire body 2 is covered with the sheath 9. 11
Are provided in a branched manner.

In the above description, the expander 8 has a property of restoring, ie, expanding, the shape stored in advance at a temperature equal to or higher than the transition temperature (Af transformation point) of the alloy. As such a shape memory alloy,
In order to be inserted into a living body, it is preferable that the transition temperature is close to or higher than the body temperature (particularly, 30 ° C to 60 ° C). Such a transition temperature can be obtained by appropriately selecting the alloy composition of the shape memory alloy. Can be In addition, a heating liquid 10 is supplied to the tubular body 8 from the introduction port 11 of the sheath 9 through between the catheter body 2 and the inner surface of the sheath 9. Water etc. can be used,
The temperature of the liquid is selected so as not to cause burns in consideration of the fact that the temperature is lowered by mixing with blood or body fluid at the insertion portion.

The dilator 8 is obtained by rewinding a wire having a shape memory so as to have a desired expanded diameter after heating to a small diameter and attaching the wire to the outer periphery of the catheter. The dilator 8 slides along the catheter tube wall. So that the part 2a of the catheter
Has a smaller outer diameter. Of course, instead of reducing the outer shape of this portion, an annular stopper made of silicone rubber or the like may be attached to the catheter.

It should be noted that in this example, the expander 8 is provided as shown in FIG.
As shown in the figure, for example, a Ni-Ti alloy (50 atomic% Ni) wire is wound once in an annular shape, and then straightened in a direction perpendicular to the diameter. This is repeated several times (four times in this example) and finally repeated. Forms a one-turn annular portion, and in this state, heat-treats it at 400 to 500 ° C. for 20 to 40 minutes to heat its shape. Then, FIG. 6 (A)
As described above, the annular portion is formed by rewinding it into a small diameter. Therefore, the expander 8 includes a plurality of annular portions 8a and a plurality of linear connecting portions 8b connecting between the annular portions. In FIG. 6 (A), the annular portion 8a is wound in a coil shape having the same diameter and contacting.

As shown in FIG. 11, the catheter 1 configured as described above is connected to, for example, the femoral artery 15 through the coronary artery of the living heart 12.
13 is inserted from the balloon 3 side (however, the drawing merely schematically shows the inserted state for easy understanding). At this time, the catheter body 2 is guided to a predetermined site by the sheath 9, and this guide is favorably performed by the guide wire 6. This guidance can be monitored by observing the catheter and the dilator 8 with an X-ray imaging apparatus.

Then, after inserting the catheter to the position of the stenosis portion 14 of the blood vessel 13 as shown in FIG. 5 (A), the balloon 3 is inflated by injecting physiological saline or the like as shown in FIG. 5 (B). Adhere to the inner wall to temporarily stop the flow of blood or body fluid. At this time, as shown in FIG. 5 (A), the dilator 8 moves the catheter body 2 forward so as to be exposed from the sheath 9.

Next, as shown in FIG.
Then, the physiological saline 10 is adjusted to a constant temperature of, for example, 50 ° C. and sent. The heated physiological saline 10 is drawn out from the inlet 11 through the inside of the sheath 9 (outer periphery of the catheter body) to the dilator 8 as shown in FIG. Although the derived physiological saline initially mixes with blood and the like, the temperature decreases, but the temperature gradually rises, and the dilator 8 is heated to the transition point or higher to expand the original shape (FIG. 5 (C)). (Indicated by a virtual line in FIG. 4). In this state, the dilator 8 has returned to the original shape of FIG. 6 (B). Thus, the extension device 8
Is changed from the shape of FIG. 6 (A) to the shape of FIG. 6 (B). However, since the dilator 8 has not the coil shape but the linear connecting portion 8b in the longitudinal direction, The longitudinal dimension does not substantially change. Therefore, as in the case of using the coil 88 of the shape memory alloy as described in FIG.
There is no danger of partial (or complete) departure from
As shown in FIG. 7C, the entire area of the stenosis wipe 14 can be easily and reliably expanded by the dilator 8.

Next, the physiological saline of the balloon 3 is removed, the balloon 3 is contracted, and the catheter is removed as shown in FIG. 5 (D). In this way, the dilator 8 can be placed in the blood vessel with the stenotic portion 14 expanded, thereby achieving the purpose of the treatment.

Since the dilator 8 is formed by processing a wire, it has flexibility as a whole. Therefore, when the distal end portion of the catheter 1 reaches the position of the stenosis portion 14 of the blood vessel 13, the dilator 8 bends following the bend when passing through the bent portion of the blood vessel, and the catheter can be easily inserted. The same applies to the case where the stenosis part is at the blood vessel bending part.

As described above, according to the catheter 1 of the present embodiment, the stenotic part of the blood vessel can be easily and reliably dilated, the restenosis can be reliably prevented, and the heating liquid for deforming the dilator can be supplied to the catheter body. Since the supply is performed not through the inside but through the outer periphery of the sheath, a sufficiently large passage can be secured, and a lower temperature can be used. Therefore,
The operation is safe, rapid injection is possible, and the catheter body itself can be made thin (there is no need for a lumen for hot liquid), so that it can be easily inserted into a thin blood vessel such as a coronary artery. Further, the flexibility of the dilator and the use of the sheath facilitate insertion of the catheter, and the insertion operation can be performed reliably.

In the state of FIG. 5 (D), the expander 8 includes a plurality of annular portions 8a.
Are separated from each other by the connecting portion 8c, so that the inner peripheral surface of the blood vessel 13 is exposed here so that endothelial tissue is generated, whereby the dilator 8 is implanted in the blood vessel 13, and This has the effect of maintaining the dilation of the stenosis part hygienically over the entire area.

The expander shown in FIG. 6 is formed by processing one shape memory alloy wire and forming the shape memory alloy wire into a ring. They can be connected to form a dilator. FIGS. 7 and 8 show the dilator formed in this manner, wherein (A) shows the shape before the original shape is restored, and (B) shows the shape after the original shape is restored.

In the dilator 18A, both ends of a plurality of annular portions 18Aa are connected by linear connecting portions 18Ab. In the dilator 18B, the central portions of the plurality of annular portions 18Ba are connected by a linear connecting portion 18Bb. Each of the dilators 18A and 18B is made of a shape memory alloy wire, and is assembled by, for example, welding.
Before returning to the original shape, the annular portions 18Aa and 18Ba are in the form of spirals in contact with each other to reduce the diameter.

FIG. 9 and FIG. 10 each show another dilator, both of which show the shape after returning to the original shape.

The dilator 18C shown in FIG. 9 has an original ring shape 18Ca, 18Ca ₂ , 18Ca.
The diameters of Ca ₃ , 18Ca ₄ , and 18Ca ₅ are formed so as to gradually change from a small diameter to a large diameter, and the respective annular portions are connected by a connecting portion 18Cb. The expander 18D shown in FIG.
8Da ₁ large-diameter annular portion 18 Da ₃ and the annular portion of the diameter of the middle located therebetween 18 Da ₂ has been connected by connecting portions 18dB. Except for the above, both extenders 18C and 18D are the same as in the extender 8 of FIG.

6 to 8 can be inserted percutaneously from the femoral artery and other parts, and is particularly effective for treatment of obstructive arteriosclerosis and treatment of trachea or bronchus described later. . The catheter to which the dilator of FIGS. 9 and 10 is assembled is particularly effective for treatment of a portion where the diameter of a blood vessel changes, such as a bifurcation of a blood vessel, or a connecting portion between a trachea and a bronchus described later.

The dilator of FIGS. 6 to 10 includes an annular portion 8a, 18Aa, 18Ba,
Only 18Ca _{1 to} 18Ca ₅ and 18Da _{1 to} 18Da ₃ can be formed with a shape memory alloy wire, and the connection portions 8b, 18Ab, 18Bb, 18Cb, and 18Db can be made of other appropriate materials. In particular, the dilator of FIGS. 7 and 8
In the case of 18A and 18B, the material cost can be reduced by doing so.

In addition to the structure shown in FIGS. 1 to 3, the catheter may have a structure shown in an enlarged plan view in FIG. 12 and an enlarged sectional view in FIG. In FIG. 13, the vertical direction is enlarged. This catheter enables insertion into luminal organs such as the trachea, bronchi, biliary tract, and esophagus, in addition to the insertion into blood vessels as described above.

The catheter 21 has a balloon 23 provided at the distal end thereof, and a routine 25 for sending (or discharging) air 24 or saline 4 to the balloon 23 is formed by being embedded along the length of the main body. I have. In the center of the main body 22, a routine 27 for passing a guide wire (not shown) and ensuring breathing is formed penetrating from the rear end to the front end. Further, a warm water injection lumen 29 for restoring the shape memory alloy to its original shape is formed by being buried along the longitudinal direction of the main body from a little behind to the tip of the balloon 23. In the main body 22, a little behind the balloon 23,
A small diameter portion 22a having a smaller outer diameter is provided, and a shape memory alloy expander 28 is attached to the small diameter portion 22a.

The dilator 28 has the same shape as the dilator 8 in FIG. 6, and is composed of a plurality of annular portions 28a and a continuous portion 28b in the longitudinal direction. As shown in the enlarged view of FIG. A coating layer made of a flexible material in the direction of the wires 28a and 28b of the Ni-Ti shape memory alloy
28c is applied, for example, by dipping. Examples of the material of the coating layer 28c include an inert polymer such as Teflon, an antithrombotic polymer such as cardiosan, a polymer capable of releasing a drug such as heparin and urokinase, a porous polytetrafluoroethylene, silicone, polyurethane, and natural In addition to rubber, chlorohydrin rubber, fluorinated rubber and the like having elasticity, polyester woven fabric or knitted fabric can be used.

FIGS. 15 (A) to 15 (E) show a procedure for treating a bronchial stenosis using the catheter shown in FIGS. 12 to 14, and all show only the bronchus 43 in cross section.

First, the catheter 21 is inserted up to just before the stenosis part 44 of the bronchi 43. At this time, the rear end step portion 22b of the main body small diameter portion 22a functions as a stopper for preventing the dilator 28 from coming off the small diameter portion 22a and remaining behind (FIG. 15 (A)).

Next, the balloon 23 is inflated with the air 4 or the physiological saline 24 or the like, and the stenotic portion 44 is expanded by repeatedly reciprocating the inflated balloon 23 at the stenotic portion 44 (FIG. 15 (B)).

Next, the catheter 21 is advanced to move the dilator 28 to the stenosis 44.
And the balloon 23 is deflated by extracting the air 4 or the physiological saline 24 (FIG. 15 (C)).

Next, the balloon 23 is inflated again so as to be in intimate contact with the inner surface of the bronchus 43 so that the hot water to be injected next does not flow toward the lungs. Subsequently, when the hot water 10 is injected and supplied to the dilator 28 from the hot water outflow part 29a, the dilator 28 becomes a shape memory alloy wire.
28a rises above the transition temperature to return to its original shape, and the diameter is expanded to expand the stenosis portion 44 (FIG. 15 (D)).

Next, the warm water 10 is drained via the warm water injection lumen (29 in FIG. 13) to keep the warm water from entering the lungs. Then, the balloon 23 is deflated, and the catheter body 22 is pulled out.
Thus, as shown in FIG. 15 (E), the expanded portion 28 obtained by expanding the stenosis portion 44 is placed in the bronchus 43, and the treatment is completed. Since the covering layer 28c is made of a flexible material, it does not hinder the dilator 28 from returning to its original shape. Further, since the coating layer 28c is made of a material having no adverse effect on the living body, it is safe. By further providing the coating layer 28c,
Even if the surface roughness of the shape memory alloy material 28a is rough, there is no problem and the surface finish can be omitted, so that the manufacturing cost can be reduced. In addition, the use of a flexible material also facilitates making the surface intentionally uneven to improve the indwellability. Further, in the treatment of blood vessels, since the coating layer 28c is formed of the above-described material, in addition to the above-mentioned safety, thrombus generation and the like are prevented.

FIG. 17 shows a catheter fitted with a shape memory alloy dilator having a transition temperature at or below body temperature and exhibiting superelasticity at or above the transition temperature.

Superelasticity refers to a phenomenon in which the strain increases significantly even if the increase in stress is slight. FIG. 16 is a graph showing the relationship between strain and tensile stress in a tensile test of a 50 atomic% Ni-Ti-Ni alloy wire in its original state. Note that the original shape is a straight line. In the range where the distortion is small, the relationship between the two is indicated by a straight line according to Hooke's law. After the distortion reaches a certain value,
Even if the increase in stress is small as in A and B, the strain increases. This phenomenon is called superelasticity, and the Ti-
This phenomenon is observed when a predetermined heat treatment is applied to a Ni alloy.

A small diameter portion 32a is formed in the main body 32 of the catheter 31 in contact with the rear end of the balloon 33 at the distal end.
A lumen 35 for supplying (or saline 24) is provided. In the center of the main body, a lumen 37 is provided buried along the longitudinal direction of the main body so as to pass a guide wire (not shown) and secure breathing (refer to a separate sheet). Is fitted with a shape memory alloy expander 38, and a fixing wire 36 is inserted through ten small rings 38c provided on the expander 38. The tip of the fixing wire has a slightly larger diameter so that the ring 38c does not come off.

FIG. 18 shows the expander 38. FIG. 18A shows the shape before returning to the original shape, and FIG. 18B shows the shape after returning to the original shape. Dilator
38 has substantially the same structure as the dilator 28 in FIGS. 12 to 14, and is formed with a plurality of annular portions 38a and longitudinal connecting portions 38b. Then, small rings 3 are provided at both ends of each annular portion 38a.
8c is provided in a pair, before returning to its original shape (Fig. 18 (A))
In FIG. 17, the pair of small rings 38c, 38c overlap each other so that the fixing wire 36 shown in FIG. 17 can be inserted.

FIGS. 19 (A) to 19 (E) show a procedure for treating a bronchial stenosis using the catheter shown in FIG. 17, and in each case, only the bronchi 43 is shown in cross section.

First, the catheter 31 is inserted up to just before the stenosis part 44 of the bronchi 43. At this time, the dilator 38 has already reached the transition temperature due to body temperature, and is trying to return to its original shape and attempt to expand its diameter.However, the fixing wire 36 inserted through the small ring 38c prevents the return to its original shape, The shape shown in FIG. 18 (A) is maintained. The rear end step portion 32b of the main body small-diameter portion 32a functions as a stopper for preventing the dilator 38 from coming off the small-diameter portion 32a and remaining behind when inserted (FIG. 19A).

Next, the balloon 33 is inflated with the air 4 or the physiological saline 24 or the like, and the stenotic portion 44 is expanded by repeatedly reciprocating the inflated balloon 33 at the stenotic portion 44 (FIG. 19B).

Next, the catheter 31 is advanced to move the dilator 38 to the stenosis 44.
And the balloon 33 is deflated by removing the air 4 or the physiological saline 24 (FIG. 19 (C)).

Next, the balloon 33 is inflated again and brought into close contact with the inner surface of the bronchus 43 to fix the catheter body 32 to the bronchus 43, and the fixing wire 36 is pulled out from the small ring 38C. At this time, the rear end step portion 32b of the small diameter portion 32a is
In addition, it functions as a stopper for preventing the rearward movement. When the wire 36 is pulled out, the dilator 38 is free to return to its original shape, and expands its diameter to expand the stenosis portion 44 (FIG. 19D).

Next, the balloon 33 is deflated, and the catheter body 32 is pulled out. Thus, as shown in FIG. 19 (E), the dilator 38 having the stenotic portion 44 expanded is placed in the bronchus 43, and the treatment is completed.

Note that the fixing wire 36 can be used also as a guide wire when the catheter 31 is inserted. If a linear wire made of a shape memory alloy showing superelasticity is used for this wire, it will easily deform following this bend in the bent part of the trachea or blood vessel, and immediately return to the original straight line in the straight part. Therefore, the insertion is extremely easy, and it can be used very conveniently as a guide wire.

The dilator 38 in FIG. 18 has ten small rings
38c is provided so that after treatment these small rings will cut into the bronchial tube wall. In the treatment of a thick-walled trachea or blood vessel, the above-mentioned bite stably holds the dilator 38 on the tube wall. The same applies to an expander 58 in FIG. 21 described later.

In the dilator 48 shown in FIG. 20, small rings 48c are provided on the inner peripheral side so that these small rings do not cut into the bronchial tube wall. FIG. 2A shows the shape before the original shape is restored, and FIG. 1B shows the shape after the original shape is restored. In the figure, 48a is an annular portion, and 48b is a connecting portion. There is no other difference from the expander 38 in FIG.

In the dilator 58 of FIG. 21, three small rings 58c facing outward are provided at both ends and the center of each annular portion 58a, and the annular portions 58a are connected by connecting portions 58b. The expander 68 of FIG. 22 has three small rings 6 facing inward at both ends and the center of each annular portion 68a.
8c is provided, and the annular portions 68a are connected by connecting portions 68b. No.
Both FIG. 21 and FIG. 22 show the shape after returning to the original shape. When both the dilators 58 and 68 process the annular portion into a small diameter after heat treatment for shape memory, this process is easy. First, the shape memory alloy wire is bent so that the small ring at one end of the annular portion and the small ring at the center overlap each other, and then the shape is formed so that the small ring at the other end is further overlapped with the small ring already overlapping. The memory alloy wire can be bent, and it is easy to form a small-diameter annular portion having the same diameter.

The dilator 48 in FIG. 20 and the dilator 68 in FIG. 22 have small rings 48c and 68c projecting inward, so that when used for treatment of a vascular stenosis, the small rings 48c and 68c Does not disturb the smooth flow of blood, and even if an antithrombotic coating is applied, there is no danger of thrombus formation. In order to prevent this, as shown in an enlarged plan view in FIG. 23 and an enlarged sectional view in FIG. 24 (a sectional view taken along the line XXIV-XXIV in FIG. 23), in the expander 78, the connecting portion 78b is annular. A curved portion that curves inward at a position immediately before connection with the portion 78a is provided, and the curved portion is used as a small ring support portion 78d, and a separately manufactured small ring 78c is swingably supported by the support portion 78d. I am trying to. By causing blood to flow in the blood vessel 13 as shown by the arrow, the small ring 78c may fall down substantially along the flow of blood, and the disturbance of blood flow may be reduced to be effective in preventing thrombus formation.

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

For example, the shape of the annular portion may be a circle, an ellipse, or any other suitable shape, the number may be an appropriate number, and the connecting portions may not necessarily be on the same line. The overall shape may be a straight shape in the longitudinal direction or a curved shape according to the purpose. The shape of the shape alloy wire is preferably one that does not return to its original shape after the transition to the original shape (irreversible transition) as in the above example, but the transition shape can be variously selected. Depending on the purpose of use, the transition may be reversible (shrinks when cooled). Further, the mounting position and the pattern of the shape memory alloy are not limited to those described above. In addition, the catheter of the present invention is inserted not only into the above-mentioned stenotic part of a luminal organ such as a blood vessel, a trachea, or a bronchus, but also into a site where these organs are thin and are likely to be torn, such as an varicose vein Prosthesis) or may be inserted into another site.

G. The living organ dilator based on the present invention, the ring-shaped portions adjacent to each other are connected by a connecting portion along the longitudinal direction, since at least the ring-shaped portion is formed of a linear body of a shape memory alloy, Before and after the restoration of the original shape, there is substantially no change in the dimension in the longitudinal direction due to the presence of the connecting portion, and only the outer diameter of the ring-shaped portion changes. Therefore, the living organ dilator can be accurately positioned and brought into contact with a blood vessel or other treatment part of the living body at the time of deformation, and reliable treatment can be performed without fear of coming off the treatment part. In addition, living organ dilators
Because the linear body is processed into the above shape, it has flexibility as a whole, and when the catheter is inserted into the living organ, even if there is a bent portion in the living organ, it is because of the above flexibility. It is deformed following the bent portion, so that insertion is easy and operability is good. In addition, it is possible to easily treat the bent portion.

[Brief description of the drawings]

1 to 24 show an embodiment of the present invention. FIG. 1 is a perspective view of a catheter, FIG. 2 is a cross-sectional view of a catheter body, FIG. 3 is a perspective view of a sheath, FIG. The figure is a cross-sectional view of the catheter showing the transfer state of the living organ dilator. FIGS. 5 (A), 5 (B), 5 (C) and 5 (D) show the insertion of the catheter into the blood vessel. 6 is an enlarged cross-sectional view of a relevant part, sequentially showing an operation for treating a stenotic part, FIG. 6 shows a living organ dilator, FIG. 6A is a perspective view before the original shape is restored, and FIG. FIG. 7 shows a living organ dilator according to another example, FIG. 7 (A) is a perspective view before returning to its original shape, FIG. 7 (B) is a perspective view after returning to its original shape, FIG. 8 shows a living organ dilator according to still another example, wherein FIG. 8 (A) is a perspective view before returning to its original shape, FIG. 8 (B) is a perspective view after returning to its original shape, FIG. 9 and FIG. Figure is a perspective view of the shape memory alloy tubular body according to still another example after returning to its original shape, FIG. 11 is a schematic view at the time of catheter insertion into the coronary artery, FIG. 12 is a plan view of a catheter according to another example, FIG. 13 is a sectional view of the same, FIG. 14 is an enlarged sectional view of a living organ dilator used for the catheter of FIG. 13 and FIG. 13, FIG. 15 (A), FIG. 15 (B), FIG. (C), FIG. 15 (D) and FIG. 15 (E) are partial cross-sectional views sequentially showing an operation of inserting a catheter into a bronchus to treat a stenosis, and FIG. 16 is a stress of a shape memory alloy. FIG. 17 is a cross-sectional view of a catheter according to still another example, FIG. 18 shows a living organ dilator used in the catheter of FIG. 17, and FIG. FIG. 19 (B) is a perspective view after the original shape is restored, and FIG. 19 (A), FIG. 19 (B), FIG. 19 (C), FIG. 19 (D) and FIG. 19 (E). In Fig. 17 FIG. 20 is a partial cross-sectional view showing an operation for treating a stenosis by inserting a catheter into a bronchus. FIG. 20 shows a living organ dilator according to still another example, and FIG. FIG. 21 (B) is a perspective view after the original shape is restored, FIG. 21 (B) is a perspective view after the original shape of the living organ dilator according to still another example is restored, and FIG. FIG. 24 is an enlarged partial plan view showing an internal use state of a living-organ dilator according to an example. FIG. 24 is a sectional view taken along the line XXIV-XXIV of FIG. FIGS. 25 (A) and 25 (B) are enlarged cross-sectional views showing a state of transition of a shape memory alloy coil in a blood vessel using a conventional catheter. In addition, in the code | symbol shown in drawing, 1,21,31 ... Catheter 2,22,32 ... Catheter body 3,23,33 ... Balloon 4 ... Saline 6 ... Guide wire 8,18A, 18B, 18C, 18D, 28, 38, 48, 58, 68, 78 ……
Living organ dilator _{8a, 18Aa, 18Ba, 18Ca 1} , 18Ca 2, 18Ca 3, 18Ca 4, 18C
a ₅ , 28a, 38a, 48a, 58a, 68a, 78a: annular portions 8b, 18Ab, 18Cb, 18Db, 28b, 38b, 48b, 58b, 68b, 78b
Connection part 9 Sheath 10 Heating liquid 13 Coronary artery (blood vessel) 14, 44 Stenosis part 28c Coating layer 38c, 48c, 58c, 68c, 78c Small ring 43 The bronchi.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-1296 (JP, A) JP-A-64-17658 (JP, A) JP-A-63-264077 (JP, A) JP-A-63-640 238872 (JP, A) JP-A-57-89859 (JP, A)

Claims (3)

(57) [Claims] 1. A plurality of ring-shaped parts are located apart from each other,
A free end for disconnecting the circumferential direction of each of these ring-shaped portions is formed in the ring-shaped portion, and these ring-shaped portions adjacent to each other are connected by a connecting portion along the longitudinal direction of the living organ dilator, A living organ dilator wherein at least the ring-shaped portion is made of a linear body made of a shape memory alloy. 2. The living organ dilator according to claim 1, further comprising a deformation preventing means for temporarily preventing deformation of the shape memory alloy linear body. 3. A catheter equipped with a living organ dilator, wherein a plurality of ring-shaped portions of the living organ dilator are located apart from each other, and the circumferential direction of each of these ring-shaped portions is freely disconnected. An end portion is formed in the ring-shaped portion, and these ring-shaped portions adjacent to each other are connected by a connecting portion along a longitudinal direction of the living organ dilator, and at least the ring-shaped portion is a linear body of a shape memory alloy. A catheter comprising: