JP2920541B2 - Living organ dilator - 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 more particularly to a living tracheal dilator used for permanently expanding a stenotic part of an organ such as a blood vessel, a trachea, or a bronchus.

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 coated with living tissue). For example, U.S. Patent No. 3,868,956 and JP-B-61
There is -6655. 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. The latter also
The shape memory alloy plate, which is formed into a cylindrical shape and stored in a normal blood vessel inner diameter, is processed into a small diameter, inserted into the desired position of the blood vessel via a catheter, and then heated by a laser beam or a high-frequency induction heating method to obtain the original shape. It is to return to.

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 breathing, the trachea is incised on 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. Accordingly, the present applicant has already proposed, as a Japanese Patent Application No. 62-97437, a catheter that can realize a dilation method for a stenotic part that is easy to operate and that is very safe to perform, regardless of the method described above. . The catheter has a blocking portion (for example, 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 portion, and is externally fitted to the catheter at a position behind the blocking portion. A shape memory alloy tubular body for restoring to a shape stored in advance at a transition temperature or higher, and a supply means for supplying a heating liquid to an outer peripheral portion of the catheter in the shape memory alloy tubular body portion. It is assumed that. 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. 16 shows a spiral tubular body (hereinafter, referred to as a tubular body) formed by spirally winding a wire of a shape memory alloy around a stenotic portion of a coronary artery using the catheter described in Japanese Patent Application No. 62-97437. A state in which the stenotic portion is to be returned to the original shape by the coil's original shape returning action,
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 20 via the pores and openings provided in the catheter, and the shape memory alloy coil
The temperature of the coil 48 is raised above its temperature (transition temperature) to expand the diameter of the coil 48 and to push and expand the stenosis 21 around the coil 48. If the inner diameter is smaller than the inner diameter, the expansion of the stenosis portion 21 becomes insufficient. Further, as shown in FIG. 16 (C), when the coil 48 deviates from the position of the stenosis 21, not only the stenosis cannot be expanded, but also the coil 48 that has returned to its original shape can no longer be used for the coronary artery.
It is not possible to correct or remove the position within 20. These post-treatments are nothing but open surgery.

D. Object of the Invention The present invention allows removal from a living organ or correction of the position within the living organ, even if it is insufficiently expanded in the living organ or is mounted out of the intended position. It is an object of the present invention to provide a living organ dilator.

E. The present invention relates to a living organ dilator for expanding a living organ, comprising a shape memory material, wherein the size (particularly diameter) of the memory shape is the size (particularly diameter) of the shape when the living organ is expanded.
And a shape change due to a temperature change is only a change from the shape at the time of expanding the living organ to the memory shape.

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

7 and 8 show the catheter, FIG. 7 is a front view, and FIG. 8 is a sectional view taken along line VIII-VIII of FIG. However, the living organ dilator (hereinafter, referred to as a prosthetic material) is shown separately from the catheter body, and is slightly enlarged in the radial direction in FIG.

The catheter 1 has a catheter body 2 made of polyethylene, vinyl chloride, silicone rubber, polyurethane elastomer, or the like, and a first balloon 3 made of elastic rubber or plastic is provided at a distal end of the catheter body 2.
A similar second balloon 4 is provided on the proximal side of the first balloon 3. Then, a lumen 6 for sending (or discharging) air or saline to the first balloon 3.
However, a similar lumen 7 is formed in the second balloon 4 so as to be buried along the length direction of the catheter body 2. Further, a lumen 9 for supplying (or discharging) warm water into a blood vessel or a trachea is embedded and formed along the length direction of the catheter body 2, and the lumen 9 is provided immediately after the second balloon 4. The opening 5 communicates with the outside of the main body. The lumen 9 is connected to a conduit 12 that branches off from the main body, so that hot water can be supplied or discharged.

The prosthetic material 8 is obtained by forming a thin plate of a shape memory material into a small-diameter cylindrical shape and storing the shape by heat treatment (details will be described later with reference to FIG. 1). And fitted around it. The first balloon 3 is inflated (or deflated to its original shape) by receiving (or discharging) air or saline from a conduit 10 (branching from the main body) via a lumen 6. The balloon 4 is inflated (or contracted to its original shape) through the lumen 7 through which air or saline is sent (or discharged) from a conduit 11 (branched from the main body). A lumen 13 for inserting a guide wire (not shown) and an insertion port 14 connected thereto are provided on the longitudinal center line of the catheter body 2.

As shown in FIG. 12, the catheter 1 configured as described above is connected to the femoral artery 22 through the coronary artery of the living heart 23, for example.
20 is inserted from the side of the first balloon 3 (however, the drawing only schematically shows the inserted state for easy understanding). At this time, the catheter 1 is guided to a predetermined site, and this guiding is properly performed by the guide wire 15 described above. In addition, the monitoring of this guide can be performed by observing the catheter 1 and the prosthetic material 8 with an X-ray imaging apparatus. The catheter 1 can be used in the same manner as described above for dilating a stenosis of a living organ such as a coronary artery and other blood vessels and trachea.

What should be noted in this example is the memory shape of the prosthetic material 8. As shown in FIG. 1 (A), the prosthetic material 8 is obtained by forming a thin plate of, for example, a Ni—Ti alloy having a large number of through holes 8a into a small diameter having a spiral cross section and storing the shape in this state. is there. The inner diameter of the prosthetic material 8 in the above-mentioned shape memory state is made as small as possible within a range that can be fitted to the second balloon 4. The prosthetic material 8 is expanded in diameter by the expansion of the second balloon 4 in the living organ, undergoes plastic deformation, maintains the expanded state, expands the stenosis, and is placed in the living organ.
FIG. 1B shows this state. That is, the relationship between the diameter of the memory shape and the diameter in the expanded state is reversed with respect to the above-described conventional prosthetic material (coil of a shape memory alloy) 48 in FIG.

FIG. 2 is an enlarged partial sectional view showing a procedure for expanding a stenotic part of a hollow organ (a blood vessel or a trachea in this example).

First, a guide wire (15 in FIG. 2) is inserted into the lumen 13 from the insertion port 14 in FIG. 8, and then the catheter 1 is inserted into a blood vessel or trachea (20 in FIG. 2) from an appropriate place. I do. Then, as shown in FIG.
To the prosthesis material 8. The position is monitored by fluoroscopy.

Next, as shown in FIG. 2B, air or physiological saline 17 is sent to the second balloon 4 to inflate the second balloon 4, whereby the prosthetic material 8 is pushed and expanded from the inside to expand the diameter. The stenosis 21 is expanded.

Next, as shown in FIG.
17 is discharged, and the second balloon 4 is contracted to its original shape. In this state, the prosthesis 8 is plastically deformed and separates from the catheter body 2 while the stenosis 21 is expanded.

Next, as shown in FIG. 2D, when the catheter body 2 is extracted, the prosthetic material 8 is placed in the blood vessel or trachea 20 with the stenosis 21 expanded.

Thus, the blood vessel or trachea no longer has a reduced diameter and the patient recovers health.

If the prosthesis 8 is located at the stenosis 21 and is properly expanded, the first balloon 3 can be omitted. This is because the first balloon 3 is not used in the above process. However, as will be described next with reference to FIG. 3, when the prosthetic material 8 is separated from the stenosis 21 and the purpose of dilating the stenosis is not achieved, the prosthetic material is also used together with the first balloon 3. 8 is corrected or removed.

 FIG. 3 shows the procedure of the above operation.

FIG. 3 (A) shows a state in which the prosthetic material 8 has been removed from the stenosis 21 and placed in the blood vessel or trachea 20.

First, as shown in FIG. 1B, the catheter main body 2 is inserted into a blood vessel or trachea 20, and the second balloon 4 is connected to the prosthetic material 8 as shown in FIG.
Within.

Next, as shown in FIG. 2C, air is sent into the first balloon 3 to inflate the first balloon 3 to close the blood vessel or trachea 20 in front of the stenosis, and to connect the catheter body to the blood vessel or trachea. Fix to 20. This blocking is performed for the following reason. That is, when hot water flows into the blood vessel or trachea 20 in the next step (D) in the same figure, if the hot water flows into the trachea, it will enter the lungs and cause a serious situation. However, in the case of a blood vessel, this occlusion can be omitted.

Next, hot water 18 is supplied from the opening 5 into the blood vessel or the trachea 20, and the prosthetic material 8 is heated to a transition temperature or higher. Then, as shown in FIG. 4D, the prosthetic material 8 returns to its original shape, reduces its diameter, and engages with the second balloon 4.

Next, as shown in FIG. 3E, the air 16 is discharged to contract the first balloon 3 to its original shape.

When removing the prosthesis material 8, the catheter body 2
Is extracted from the blood vessel or trachea 20 together with the prosthetic material 8. Then, repeat the processing.

When correcting the position of the prosthetic material 8, the stenosis 21 is expanded by the prosthetic material 8 from the state of FIG. 3 (E) according to the above-described procedure of FIGS. Is placed in a blood vessel or trachea 20.

Thus, the prosthesis is correctly repositioned and the medical procedure ends with no reduced diameter portion of the blood vessel or trachea.

As described above, the shape change of the prosthetic material due to the temperature change
Since it is only a return from the expanded state in the blood vessel or trachea to the original shape with a smaller diameter (FIG. 3 (C) → FIG. 3 (D)), the above-mentioned shape change is ensured only by one hot water supply. Is made.

The shape recovery temperature of the prosthetic material 8 is preferably higher than the body temperature and a temperature that does not cause a burn, particularly 40 to 60 ° C.
Is preferred. The transition temperature is determined by the heating temperature during the heat treatment for shape memory and the holding time at this temperature. Further, since the deformation of the prosthetic material 8 due to the temperature change is only in the diameter-reducing direction, the heat treatment for shape memory is easy only once, and the reliability of the restoration to the original shape is high.

A large number of through holes 8a are provided in the peripheral wall of the prosthetic material 8, and endothelial tissue is generated from blood vessels or trachea with the passage of time in the state of FIG. 2 (D). The prosthesis 8 is implanted in the blood vessel or trachea 20, and has the effect of hygienically maintaining the expansion of the stenosis for a long period of time.

It is desirable that the prosthetic material 8 be covered with a material having plasticity and excellent compatibility with a living body. As such a coating material, a polyester woven or knitted fabric; a porous polytetrafluoroethylene film; a silicone, polyurethane or poly (meth) acrylate film can be used. It is also possible to laminate a thin cloth made of the above-mentioned film material. Further, the coating material may be a material having antithrombotic properties such as, for example, pepperin. These coatings facilitate the embedding of the prosthetic material due to the formation of endothelial tissue as described above, or also help prevent thrombus.

FIG. 4 is an enlarged partial cross-sectional view of the prosthetic material provided with such a coating. On the surface of the prosthetic material 8 made of a shape memory material, the above-mentioned coating material layer 8c including the inner peripheral surface of the through hole 8a is applied.

In addition, as shown in an enlarged view in FIG. 5, when irregularities 8 d are formed on the surface of the prosthetic material 8 of the shape memory material, or as shown in an enlarged view in FIG. 6, in addition to the covering material 8 c in FIG. Alternatively, if the fiber 8e of the above-mentioned material is implanted, the fixation to the blood vessel or trachea is further improved.

When inserting a catheter into a blood vessel or trachea,
It is desirable to take measures to keep the second balloon 4 from deviating from the position of the second balloon 4. 9 and 10 are enlarged partial front views of the catheter body in this way.

In the catheter body of FIG. 9, point-like small projections 4a projecting outward on the circumference of the outer peripheral surface are provided radially at the front end and the rear end of the second balloon 4. In the catheter body of FIG. 10, an annular projection 4b is provided in place of the small point projection 4a of FIG. The prosthesis material (not shown) externally fitted to the second balloon 4 is locked to the pair of small projections 4a or the annular projections 4b, is stably held around the second balloon 4, and may be detached therefrom. Disappears.

If a cylindrical net is fitted over the first balloon 3 and the second balloon 4 (particularly the second balloon 4), these balloons are reinforced and the diameter at the time of inflation can be regulated. It is convenient.

FIG. 11 shows a catheter main body in which a cylindrical mesh 19 made of knitted fibers of Teflon, polyethylene, nylon, polyester or the like is externally fitted (or embedded) in the second balloon 4 or the mesh is dipped in rubber. In FIG. 7A, the second balloon 4 is deflated, and the diameter of the cylindrical mesh 19 is reduced so that it is folded irregularly. When the second balloon 4 is inflated, the cylindrical mesh 19 expands in diameter and assumes a cylindrical shape as shown in FIG. 4B, and the second balloon 4 is no longer inflated. Therefore, while the tubular mesh 19 reinforces the second balloon 4, the prosthesis (not shown) fitted to the tubular mesh 19 only increases in diameter when expanded to a predetermined diameter. The stenosis of the blood vessel or trachea is prevented from being unnecessarily expanded, and the medical procedure is safely performed. In addition, the small projection 4a in FIG.
When the catheter is inserted, it can be prevented from biting into the tubular mesh 19 and coming off from the second paroon 4. The same effect can be obtained by applying the cylindrical mesh 19 to the first balloon 3. Therefore, it goes without saying that the tubular mesh 19 may be applied to one or both of the first balloon 3 and the second balloon 4. When the cylindrical mesh 19 is externally fitted to the first balloon 3, the small projections 4a shown in FIG.

As described with reference to FIGS. 2 and 3, the first balloon 3 is used to directly obstruct the stenosis of the blood vessel or trachea and block the passage, and the second balloon 4 is used for the prosthetic material. 8 is used to expand the stenosis through it. By assigning the first and second balloons to perform their respective functions, the burden on these balloons is reduced, and the design of the catheter body is facilitated. In addition, when the two types of roles are shared by a single balloon, it is easy to reliably block the passage.

The prosthetic material may have the following shape in addition to the shape of the prosthetic material 8 described above.

The prosthetic material 28A in FIG.13A is formed by forming a plate of a plate-shaped shape memory material into a cylindrical shape, and is provided with a number of slits 28Aa.The prosthetic material 28B in FIG.13B is also a rib-shaped cylindrical material. And a number of slits 28Ba are provided. 13th C
The prosthetic material 28C shown in the figure is formed by shaping a plate of a shape memory material into a truncated cone shape, and is used for expanding a portion where the diameter of a blood vessel or trachea changes. 13A, 13B, and 13C all show a state where the diameter is expanded. The prosthetic material 28D in FIG.13D is a cylindrical shape of a shape memory material plate having no through hole,
The prosthetic material 28E in FIG. E is obtained by processing a pipe made of a shape memory material into a small diameter by folding the pipe in the radial direction, and shows a state in which the diameter is reduced (memory state). It has a large cylindrical shape. Prosthesis 28 in FIG.13C
C, both the prosthetic material 28D in FIG. 13D and the prosthetic material 28E in FIG. 13E are provided with the same through-hole 8a as described above, the same through-hole or slit as the slit 28Aa in FIG. 13A or the slit 28Ba in FIG. 13B. Needless to say good things.

13A to 13E are examples of the prosthetic material formed by molding a plate or tube of a shape memory material, but the material may be a band material or a wire material.

FIG. 13F shows a prosthetic material 28F formed by spirally winding a band of the shape memory material, and FIG. 13G shows a prosthetic material 28G formed by spirally winding a wire of the shape memory material. Figure 14A shows prosthetic material 28F
2 shows a cross section of FIG. The cross section of the prosthetic material 28G may be circular as shown in FIG. 14C or elliptical as shown in FIG. 14E. In addition to the close molding as described above,
As shown in FIG. 14B, FIG. 14D, and FIG. 14F, a spiral may be formed at intervals. By providing the above interval,
Advantageously, the aforementioned endothelial tissue facilitates implantation in blood vessels or trachea. The prosthetic material 28H in FIG. 13H is obtained by further forming a coil of a shape memory material into a spiral shape. 13th
The prosthetic material 28I shown in the figure and the prosthetic material 28J shown in FIG. 13J are obtained by partially shaping a wire made of a shape memory material into a helical shape having a different diameter. Used for The prosthetic materials 28F to 28J in FIGS.
Each shows a state where the diameter is expanded.

13A to 13J may be subjected to the same surface treatment as described above.

As the material of the prosthetic material, a shape memory resin can be used in addition to the shape memory alloy. The shape memory resin is a resin having a function of restoring the original shape similar to the shape memory alloy, and is an example of a norbornene resin (for example, trade name Nosorex). In addition, there are trans-1,4-polyisoprene, styrene / butadiene copolymer and polyurethane. The shape memory resin is the following resin. The shape at the time of thermoforming (primary molding) is stored at room temperature, and it is secondarily molded to another shape at a temperature higher than the glass transition temperature (Tg) and lower than the primary molding temperature, and then returned to room temperature . When this is heated again to a temperature higher than the glass transfer temperature and lower than the primary molding temperature, the shape returns to the stored shape at the time of the primary molding.

Figures 13A to 13J (particularly Fig. 13A to Fig. 13)
13F (preferably FIG. 13F) prostheses 28A-28J (especially 28A-28F) can be manufactured. In addition, a cylindrical prosthetic material 38A as shown in FIG. 15A and a mesh-shaped cylindrical prosthetic material 38 as shown in FIG. 15B.
B is good. The same applies to a prosthetic material made of a shape memory alloy.

Although the embodiment of the present invention has been described above, various modifications can be made to the above-described example based on the technical idea of the present invention. For example, the prosthetic material, the first balloon, and the second balloon may have a circular outer shape, an oval other appropriate outer peripheral shape, a straight shape in the length direction, and a curved shape according to the purpose. Good as In addition, the prosthetic material may have an appropriate shape other than the cylindrical shape depending on the purpose. As for the shape of the shape memory alloy or the resin, it is preferable that the shape does not return to the original shape after the transition to the original shape (irreversible transition) as in the above-described example, but the transition shape can be variously selected. Further, the mounting position and the pattern of the shape memory material are not limited to those described above. The diameter expansion of the prosthesis may be in the direction of another mechanical expansion of the prosthesis, in addition to the expansion of the second balloon. Further, the prosthetic material is inserted not only into the stenotic part of the luminal organ such as a blood vessel, a trachea or a bronchus as described above, but also into a site where these organs become thin and are likely to be torn, such as an arteriovenous vein (ie, prosthesis). Or may be inserted into another site. The catheter body is provided with a sheath (cylindrical body 49 in FIG. 16) which is externally fitted to the catheter body in place of the lumen 9 in FIG. 8, so that hot water is supplied to the prosthesis from between the sheath and the catheter body. Good. As the fluid to be supplied to the first balloon and the second balloon, a liquid such as warm water, an infusion solution, and a contrast agent can be used in addition to air or physiological saline. Lumen 13
(See FIG. 8), a contrast agent may be injected in addition to the guide wire.

G. Effects of the Invention Since the living organ dilator based on the present invention changes the shape from the shape at the time of expanding the living organ to only the smaller memory shape due to temperature change, even after expanding the living organ. By returning to the memory shape, it can be separated from the living organ. Therefore, when the living organ expansion is insufficient or is fixed to the living organ by deviating from the position to be expanded, the living organ dilator is removed from the living organ and the work is repeated or the position is corrected in the living organ. Can be done easily. In addition, since the shape change due to the temperature change is performed only in one direction as described above, the shape can be accurately returned to the predetermined shape, the reliability is high, and the structure is easy.

[Brief description of the drawings]

1 to 15 show an embodiment of the present invention. FIG. 1 shows a living organ dilator (prosthetic material), and FIG.
Is a perspective view in a memory shape, FIG. 2B is a perspective view when the diameter is expanded, FIG. 2A, FIG. 2B, FIG. 2C and FIG.
Are enlarged partial cross-sectional views (partially perspective views) showing a procedure for expanding a stenotic part of a blood vessel or a trachea, respectively, FIG. 3 (A), FIG. 3 (B), FIG. 3 (C), FIG. FIG. 4E is an enlarged partial cross-sectional view (partially perspective view) showing a procedure for reducing the diameter of a prosthetic material placed in a blood vessel or trachea by enlarging the diameter of the prosthetic material and allowing the position to be corrected or removed; 5 is an enlarged partial sectional view of the prosthetic material, FIGS. 5 and 6 are enlarged partial front views of the prosthetic material according to other examples, respectively, FIG. 7 is a front view of a catheter showing the prosthetic material separately from the catheter body, 8 is a sectional view taken along line VIII-VIII of FIG. 7, FIGS. 9 and 10 are enlarged partial front views of a catheter body according to another example, and FIG. 11 shows a catheter body according to still another example. Figure (A) is an enlarged partial front view before diameter enlargement, Figure (B) is an enlarged partial front view at diameter enlargement, and Figure 12 is a catheter to the coronary artery. Schematic view of Nyutoki, FIG. 13A, FIG. 13B, the 13C view, FIG. 3D, second 3E view, the 13F
Figures, 13G, 13H, 13I and 13J are enlarged perspective views of prosthetic materials according to other examples, respectively, FIGS.14A, 14B, 14C, 14D, 14E, and 14E. First
FIG. 4F is an enlarged partial cross-sectional view of the spiral prosthesis, and FIGS. 15A and 15B are enlarged perspective views of a prosthesis according to still another example. FIG. 16 shows the transfer state of a shape memory alloy coil in a blood vessel using a conventional catheter. FIG. 16 (A) is an enlarged cross-sectional view before transfer, and FIGS. It is an enlarged sectional view after. In addition, in the code | symbol shown in drawing, 1 ... catheter 2 ... catheter main body 3 ... 1st balloon 4 ... 2nd balloon 5 ... opening for warm water injection 6, 7, 9, 13 ... lumen 8, 28A, 28B, 28C, 28D, 28E, 28F, 28G, 28H, 28I, 2
8J, 38A, 38B …………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… ••••••• ··· Or a tracheal stenosis.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-17658 (JP, A) JP-A-63-160644 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) A61M 25/00-29/04

Claims (1)

(57) [Claims] 1. A living organ dilator for expanding a living organ, comprising a shape memory material, wherein the size of the memory shape is smaller than the size of the shape when the living organ is expanded, and
A living organ dilator wherein the shape change due to temperature change is only a change from the shape at the time of expanding the living organ to the memory shape.