Catheter

Abstract

To provide a catheter used for various applications by sensing the temperature in the body and changing its shape, rigidity, and stress relaxation property.SOLUTION: A catheter 100 uses a 4-methyl-1-pentene-α-olefin copolymer whose glass-transition temperature is 23-38°C and a composition containing the copolymer. The tip is softened or deformed to a predetermined shape that is memorized by the temperature in the body. Thereby, the catheter can be deformed to a predetermined shape in the body.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a catheter.

Background Art

[0002] There has been proposed a catheter device in which a bent portion at the end of a catheter for cardiovascular or angiographic use can be quickly and easily adjusted inside a patient (Patent Document 1). Such a catheter device extends through a sheath that is several centimeters shorter than the catheter by at least the length of the bent end segment of the catheter, and the shape of the curved portion at the end of the catheter can be changed by advancing the sheath on the catheter. The sheath has sufficient rigidity, and as a result, when the sheath advances on the catheter, the curved portion of the catheter can be directed in a direction in which it straightens while the shape of the curved portion of the catheter gradually changes.

[0003] However, the rigidity of the curved portion of such a catheter was constant and could not be changed. Also, the shape of the curved portion was fixed, and its form could not be specified after the catheter was manufactured.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Therefore, the present invention has been made to solve the above-described problems, and an object thereof is to provide a catheter having various uses by sensing the temperature inside the body and changing its form, rigidity, and stress relaxation properties.

Means for Solving the Problems

[0006] In order to achieve the above object, the present invention employs the following means.

[0007] The catheter according to the present invention comprises: The composition comprises a 4-methyl-1-pentene and α-olefin copolymer having a glass transition temperature of 23°C to 38°C, and a composition containing the polymer; The tip is characterized by being softened or deformed into a predetermined shape that has shape memory due to the temperature inside the body.

[0008] The catheter according to the present invention is made using 4-methyl-1-pentene and α-olefin copolymer and a composition containing said polymer, "Absortomer (registered trademark)" (manufactured by Mitsui Chemicals, Inc.). This composition is easy to soften within the glass transition temperature range and has shape memory properties, so it is relatively hard when outside the body, but when inserted into the body it gradually softens and deforms into the shape-memorized form, and these properties can be utilized to make a variety of catheters.

[0009] In the catheter according to the present invention, the predetermined shape may be a curved shape.

[0010] By making the predetermined shape of the shape memory at the tip curved, an appropriate curved shape can be selected depending on the lesion site, which makes it possible to insert the device into difficult-to-insert locations during catheterization procedures and to quickly and easily reach embolization sites. This makes it possible to provide a catheter that can shorten the procedure time and is minimally invasive for patients, with the expectation of a good prognosis.

[0011] Furthermore, in the catheter according to the present invention, the predetermined shape may be a spiral shape.

[0012] By making the predetermined shape of the shape memory at the distal end into a spiral shape, it can be used as a stent retriever or as an embolization coil for coil embolization performed in the treatment of aneurysms.

[0013] Furthermore, in the catheter according to the present invention, the predetermined shape may be a bellows shape.

[0014] By making the predetermined shape of the shape memory at the distal end into a bellows shape, it can be used as an alternative to a balloon catheter.

[0015] Furthermore, in the catheter according to the present invention, the catheter may be characterized in that temperature-sensitive dye capsules are mixed therein.

[0016] By mixing temperature-sensitive dye capsules in the catheter, the color of the catheter changes depending on the temperature, so that the body temperature can be measured, and the catheter can be made suitable for the shape memory of the absorbable polymer.

[0017] Furthermore, in the catheter according to the present invention, the temperature-sensitive dye capsules may be arranged at predetermined intervals in the catheter.

[0018] By adopting such a configuration, it can be used as a measuring catheter for measuring the length inserted into the body and different parts with different body temperatures.

Advantages of the Invention

[0019] According to the catheter of the present invention, by sensing the body temperature and changing its form, rigidity, and stress relaxation, a catheter having various uses can be provided.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0021] Next, embodiments of the catheter 100 according to the present invention will be described in detail with reference to the drawings. It should be noted that the embodiments and drawings described below are examples of a part of the embodiments of the present invention, and are not used for the purpose of limiting to these configurations, and can be appropriately changed without departing from the gist of the present invention.

[0022] (First Embodiment) The catheter according to the first embodiment is made using a 4-methyl-1-pentene and α-olefin copolymer having a glass transition temperature between 23°C and 38°C and a composition containing the polymer (hereinafter referred to as "4-methylpentene-1 polymer"). "Absortomer (registered trademark)" (manufactured by Mitsui Chemicals, Inc.) is used. The 4-methylpentene-1 polymer has thermosensitivity (temperature dependence), is hard under an external atmosphere, has the property of changing flexibility according to body temperature and becoming soft at body temperature. Further, it has shape memory, and can be gradually softened by being inserted into the body and deformed so as to return to the shape in which the shape is memorized.

[0023] A first embodiment of such a catheter 100 will be described. As shown in FIG. 1A, the catheter 100 according to the first embodiment has its tip 10 memorized in a bent shape curved into a J shape. Such a catheter 100 is made of a resin containing a 4-methylpentene-1 polymer in the same manner as a normal catheter (for example, extrusion molding, etc.) to produce a straight catheter 100. After that, once it is shaped into a predetermined shape at a temperature above the glass transition point temperature, in this embodiment, the tip 10 is bent into a J shape, and after cooling, it is deformed back into a straight shape. When softened, it is shape-memorized in the bent shape curved into the J shape before cooling, and when softened at body temperature, the tip 10 will be deformed into a predetermined shape.

[0024] According to the catheter 100 manufactured in this way, there are the following advantageous points. Generally, when inserting a conventional catheter 200 into a blood vessel, the tip is often bent or bent into a shape according to the blood vessel to be finally inserted. In this case, as shown in FIG. 1B, when trying to insert the tip of the catheter 200 into an inserter, sheath or various connectors 50, etc., the tip bending may get caught. On the contrary, according to the catheter 100 of the present invention, since it is exposed to the external atmosphere at the insertion stage and has a straight shape, it is easy to insert into an inserter, sheath or various connectors 50. After entering the body, it deforms at the body temperature, so it is difficult to come off after insertion, and it can be made into a catheter that is easy to handle.

[0025] Also, before softening due to body temperature, when in the external atmosphere, it is a relatively rigid and hard catheter. So, when inserting into the body, it has high pushability and is easy to insert. After that, after reaching the affected part, it gradually softens due to body temperature and changes into a predetermined shape, so it is easy to select blood vessels and easy to reach the obliterated blood vessels.

[0026] Utilizing these properties, it can be used as the following catheter.

[0027] (Example 1) It can also be used when inserting a catheter into a blood vessel at a location where it is difficult to insert with a normal straight catheter. For example, when it is desired to insert catheter 100 from the left subclavian artery 91 through the aortic arch 92 into the left common carotid artery 93, as shown in FIG. 2A, for example, passing it from the elbow root to the left subclavian artery 91 and inserting catheter 100 into the aortic arch 92, the catheter 100 is still before being softened by body temperature, is straight and highly rigid, so it has high pushability and can be inserted smoothly. When the tip 10 of catheter 100 reaches the aortic arch 92, wait for a while for the tip 10 of catheter 100 to deform into the curved shape memorized by the body temperature in the blood vessel. As a result, when it deforms into a curved shape, the tip 10 of catheter 100 will face in the direction of the left common carotid artery 93 at an acute angle position, making it easier to insert catheter 100 into the common carotid artery 93. In this way, it is possible to provide a catheter that is easy to insert into blood vessels at locations where insertion is generally difficult.

[0028] (Example 2) Next, an example of using it as a stent retriever will be described. The catheter 110 according to Example 2 used as a stent retriever is shown in FIG. 3. The catheter 110 according to Example 2 has a tip portion 10 shaped and memorized in a spiral shape. The method of memorizing the shape of the tip portion 10 is the same as that of the first embodiment. Generally, a stent retriever is made of a metal wire such as a nickel-titanium wire shape-memorized in a basket shape, and unfolds in a basket shape by being exposed from a delivery catheter or the like, and entangles and retrieves thrombi or the like. While the catheter 110 according to this Example 2 is being sent through the delivery catheter 51, it is hardly affected by body temperature and is linear and highly rigid. Even if the catheter 110 is exposed from the delivery catheter 51 into the blood vessel 94 from this state, it does not deform immediately and remains in a highly rigid linear shape. Therefore, it can penetrate through the thrombus 95 by being pushed in while maintaining a high-rigidity state. If it is left in this state for a while, the tip portion 10 of the catheter 110 changes into a spiral shape due to body temperature and entangles with the thrombus 95. The thrombus can be entangled by pulling out the catheter 110 from this state. In this way, the spiral shape of the tip portion 10 of the catheter 110 can function as a basket-shaped portion of a conventional metal wire, and thus it can be used as a stent retriever.

[0029] Compared with the case of using a metal wire stent retriever, since the resin wire is softer than the metal wire, the risk of damaging the blood vessel can be reduced. In addition, although a metal wire is likely to kink or break when bent at an acute angle or shaped, since the resin wire is soft, there is an effect that such problems can be prevented while performing complicated shaping.

[0030] (Example 3) Furthermore, as shown in FIG. 4, it can be used as an embolization coil for coil embolization performed in the treatment of aneurysm 96. The catheter 120 according to this embodiment is formed with shape memory so that its tip becomes spherical. The catheter 120 formed in this way is delivered to the aneurysm 96 using the delivery catheter 51, and by placing the catheter 120 in the aneurysm 96, it can be deformed into a spherical shape by body temperature and function in the same way as an embolization coil. Since it is deformed into a spherical shape at body temperature in this way, it can be made difficult to protrude from the aneurysm 96. Also, the embolization coil of metal wire is generally made by coiling an extremely thin metal wire to impart softness, and is very difficult and expensive to manufacture. However, in the catheter 120 according to this embodiment, the portion corresponding to the embolization coil is made of resin and becomes soft at body temperature and automatically deforms into a spherical shape. Therefore, it is not necessary to manufacture it in a coil shape and it can be manufactured at low cost.

[0031] (Example 4) Furthermore, it can be used as an alternative to a balloon catheter. As shown in FIG. 5, the catheter 130 according to this embodiment is formed with shape memory so that the distal end portion 10 is deformed into a bellows shape and the diameter becomes thicker. According to such a catheter 130, for example, it can be used as an alternative to a balloon catheter for preventing thrombus from flying. In the case of a normal balloon catheter, the balloon is inflated in the blood vessel to occlude the inside of the blood vessel and prevent the thrombus from flying with the balloon. However, in the catheter 130 according to this embodiment, the catheter 130 is inserted to a desired location by the delivery catheter 51, the distal end portion 10 is exposed from the delivery catheter 51, and by placing the distal end portion 10 at the indwelling position, the distal end portion 10 is deformed into a bellows shape, the diameter becomes thicker, and the blood vessel can be embolized. Thus, according to the catheter 130 according to this embodiment, it is not necessary to control the balloon expansion fluid, and the blood vessel can be easily embolized.

[0032] (Second Embodiment) The catheter 150 according to the second embodiment is manufactured by mixing thermosensitive dye capsules so that its color changes with respect to the catheter 100 according to the first embodiment. The thermosensitive dye is a microencapsulation of a component that reversibly changes between (color development) ←→ (color fading) depending on temperature, and can develop color on the lower temperature side than a certain specific temperature and fade on the higher temperature side. By mixing such thermosensitive dye capsules, the color of the catheter 150 can be changed according to the body temperature. As the thermosensitive dye capsules, for example, thermosensitive dye capsules manufactured by Nippon Capsule Products Co., Ltd. can be preferably used.

[0033] Thereby, for example, as shown in FIG. 6, by using the endoscope screen in the stomach or intestine, by visually recognizing the color of the catheter 150 on the screen, contact temperature measurement of the internal body part can be performed.

[0034] Also, as shown in FIG. 7, by arranging the thermosensitive dye capsules at predetermined intervals from the tip, it can be used as a measuring catheter for measuring the inserted length or parts with different body temperatures. For example, when performing a treatment by a technique (cauterization) of burning and killing a lesion such as a cancer cell, by taking out the catheter inserted into the body and checking the color, it can be determined whether the lesion has reached the target temperature.

Industrial Applicability

[0035] As shown in the above-described embodiments, it can be used as a catheter applicable in various scenarios.

Explanation of Reference Numerals

[0036] 10…tip portion, 50…various connectors, 51…delivery catheter, 91…left subclavian artery, 92…aortic arch, 93…common carotid artery, 94…blood vessel, 95…thrombus, 96…aneurysm, 100…catheter, 110…catheter, 120…catheter, 130…catheter, 150…catheter, 200…catheter

Claims

1. A catheter made by using a 4-methyl-1-pentene and α-olefin copolymer having a glass transition temperature between 23°C and 38°C and a composition containing the copolymer, characterized in that the tip is deformed into a curved shape, a spiral shape or a bellows shape whose shape is memory-shaped by the temperature inside the body.

2. The catheter according to claim 1, characterized in that an inserter, a sheath or a connector is inserted.

3. The catheter according to any one of claims 1 or 2, characterized in that a thermosensitive dye capsule is mixed in the catheter.

4. The catheter according to claim 3, characterized in that the thermosensitive dye capsules are arranged at predetermined intervals in the catheter.

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