JP2001046532A - Radiation irradiation catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a radiation wire from coming out into blood vessel though the guide wire can go out into a blood vessel over the tip end part by making the guide wire and the radiation wire pass through the same lumen and the diameter of the lumen reduced around the tip end part and specifying the size of the smallest diameter part. SOLUTION: This catheter 12 comprises a shaft with a lumen and a manifold 27. The diameter of the tip end part of the shaft is reduced toward the distal end side. The shaft comprises the distal shaft 14 and the proximal shaft 15. The lumen of the haft is commonly used for passing the guide wire 11 and the radiation wire 7. The smallest inner diameter around the tip end part of the lumen is set at a size larger than the outer diameter of the guide wire 11 but smaller than the outer diameter of the radiation wire 7. Thus the guide wire 11 can come into a blood vessel over the tip end part but the radiation wire 7 cannot come into the blood vessel because motion of the radiation wire 7 is obstructed around the tip end of the lumen.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical device for preventing restenosis, which occurs repeatedly within several months after stenosis of a blood vessel, particularly a coronary artery, and is used to widen a stenosis or to expand a stenosis. After performing (coronary) arterial angioplasty (PTCA or PTA) known as a treatment such as placing a support material called a metal or polymer stent on the stenosis affected area from inside the blood vessel The present invention relates to an irradiation catheter.

[0002]

2. Description of the Related Art Conventionally, for treatment of intravascular stenosis, particularly coronary stenosis, which causes myocardial infarction or angina, etc.
PTCA (Percutaneous Transluminal Coronary Angio
plasty; percutaneous transluminal coronary angioplasty) Balloon catheters have been used. In this type of balloon catheter, a balloon that can be expanded, contracted, and folded by adjusting the internal pressure is joined to the distal end of a shaft tube having one or more lumens (lumens), and a manifold is joined to the proximal end of the shaft tube. It is configured as The shaft tube generally has at least two lumens: an inflation lumen for passing a pressure fluid for applying an internal pressure to the balloon, and a guide wire lumen for passing a guide wire for guiding a catheter.

[0003] A procedure using such a balloon catheter is performed in the following procedure. First, prior to guiding the balloon catheter to a lesion site such as a stenosis, a guiding catheter having an outer diameter of about 2 mm to 3 mm in the middle lumen is guided into the aorta, and the distal end thereof is placed at the entrance of the coronary artery. Then, a guide wire having an outer diameter of about 0.010 inch to 0.035 inch is passed through the guiding catheter to the lesion site of the coronary artery. Next, the balloon catheter is guided to the coronary artery along the guide wire, and the balloon is passed through and placed at the lesion site. Then, a pressure fluid such as a high-pressure physiological saline solution or a contrast medium is supplied to the balloon through the inflation lumen using a syringe or the like, and the balloon is inflated to forcibly dilate the lesion site. After confirming the dilation treatment, the balloon was deflated under reduced pressure and removed from the body.
End CA.

[0004] However, PTCA does not
About 4 months restenosis (repetitive stenosis) in a short period of 6 months to 6 months
There is a problem that it occurs with a probability of 0%. As a mechanism of restenosis, it has been proved that forcible dilation of a blood vessel lumen by a balloon damages the blood vessel wall and is caused by excessive proliferation of smooth muscle cells in the subsequent healing process. In addition, after the stenosis is subjected to dilation treatment,
Although it has been confirmed that if a stent (metal mesh or coil) is kept in place, the incidence of restenosis is reduced to 20% or less, this incidence is reduced as much as possible from a clinical viewpoint. It is urgent.

On the other hand, in recent years, as a method for preventing restenosis in the United States and Europe, a clinical practice of an intravascular irradiation treatment method in which a lesion site is irradiated with an appropriate dose of radiation after balloon inflation to suppress cell proliferation in the healing process. Although some clinical trials have reported that the incidence of restenosis can be reduced to about 7%, although some clinical trials have been pursued. It is said that such a favorable result is obtained by irradiating a lesion with an appropriate dose of radiation after balloon inflation can suppress cell proliferation during the healing process.

[0006] As a treatment system currently used for this purpose, there is an intravascular irradiation catheter, which is disclosed in US Patent No. 5,199,939 and Japanese Patent Application Laid-Open No. 9-508.
No. 038. This is performed after dilatation of the lesion with a PTCA balloon catheter or after placement of a stent. US Patent No. 5,199,93
As shown in FIG. 1, after the PTCA treatment, the system disclosed in Japanese Patent Application Publication No. 9-101115 draws a PTCA balloon catheter (not shown) out of the body, and then, emits an intravascular irradiation catheter having a lumen 1 (patent). In the specification, this is referred to as a probing catheter 2) and guided to reach the vicinity of the lesion 3. A radiation source having a plurality of radioactive isotopes 4 and spacers 5 near the tip is provided.
(Radiation wire) 7 is guided through the lumen 1 of the intravascular irradiation catheter to the lesion site 3, and is irradiated with radiation from a radiation source for a predetermined time.

The system disclosed in Japanese Patent Publication No. 9-508038 is an intravascular irradiation catheter 8 having two lumens as shown in FIG. 2, that is, a lumen 9 through which a guide wire passes. And the lumen 1 through which the radiation wire passes
0. First, it is assumed that the guide wire 11 passes through the stenosis. Then, as shown in FIG. 3, the intravascular radiation irradiation catheter 8 is guided and reaches the lesion 3 along the guide wire 11. The guidewire 11 will pass through the lumen 9 and beyond the distal end. Then, a radiation source having a plurality of radioactive isotopes 4 and spacers 5 near the tip is provided, and a wire (radiation wire) 7 covered with a resin tube 6 is passed through another lumen 10.
This is a system that guides and reaches a lesion site 3 and radiates radiation from a radiation source for a predetermined time.

When the irradiation is completed, the radiation wire 7 is pulled out of the body (recovery), and the intravascular irradiation catheter 2 or 8 is also drawn out of the body, thus completing the treatment. The operation of guiding and collecting the radiation wire 7 is performed by a remote automatic operation by a device called a remote loader / unloader in order to prevent an operator from being exposed to radiation, as is generally performed in the field of cancer treatment. Is common. This remote loader / unloader device is a device having a radiation-shielded outer frame, which functions as a storage for storing radiation wires in the device when not in use, and is remotely operated when in use, The operator can control this device from a remote location to guide and retrieve the radiation wire in the catheter. That is, without such a device, the surgeon would have to guide the radiation wire himself into the catheter, in which case a considerable amount of exposure would be unavoidable. Remote loaders / unloaders are used to eliminate such problems. Catheters using this type of radiation source are described in US Pat. No. 5,199,939 and US Pat. No. 5,302,168 (“METHOD AND APPARATUS F
OR RESTENOSIS TREATMENT "), US Patent No. 5,21
No. 3,561 (“METHOD AND DEVICES FOR PREVENT
ING RESTENOSIS AFTER ANGIOPLASTY "), Tokuyohei 10-
No. 507951 ("Vascular treatment method").

However, the above-mentioned prior art technique has the following problems. First, in the method of US Pat. No. 5,199,939, as shown in FIG. 1, the above-mentioned radiation wire 7 is guided to reach the lesion 3 through the lumen 1 of the probing catheter 2, and this probing is performed. The material of the catheter 2 is a resin. Normally, in order to guide a catheter made of resin, a wire made of a metal, such as the above-mentioned guide wire, is passed through the intravascular stenosis in advance as a guide before guiding. Without this guidewire, it is practically impossible to select and guide a bent blood vessel or a branched blood vessel even if a catheter made of resin is reinforced with metal. The technique described in U.S. Pat. No. 5,199,939 has neither a probing catheter nor a radiation wire having a lumen through which such a guidewire passes. Therefore, guiding this probing catheter without a guidewire is very difficult in practice. Further, in this technique, as shown in FIG. 1, the radiation wire 7 goes beyond the distal end of the probing catheter 2 and enters the blood vessel. If the lesion causes calcification,
In the case of a hard and sharp blood vessel wall, the coating tube 6 of the radiation wire 7 repeatedly contacts the blood vessel wall, thereby damaging the coating tube 6 and causing the radioactive isotope disposed inside to come into contact with blood. Risk of accident. This can be a fatal flaw when considering safety.

In general, for a catheter passing through a small-diameter, highly-flexible blood vessel such as a coronary artery, it is strongly required that the outer diameter of the catheter be as small as possible. This is because when guiding the catheter into the coronary artery, if the outer diameter of the catheter is large, the contact friction with the coronary artery increases, and the operability decreases. If the outer diameter of the catheter is large, in the worst case, it may not be possible to push the catheter into the peripheral side of the coronary artery at all. In the case of Japanese Patent Publication No. 9-508038, FIG.
As shown in (2), since the intravascular radiation irradiation catheter 8 has two lumens, the outer diameter of the intravascular radiation irradiation catheter 8 becomes large. The outer diameter of the guide wire 11 generally used in coronary artery treatment is 0.014 inch (0.
36 mm). Further, the outer diameter of the radiation wire 7 is equal to 0.
It is generally referred to as 40 mm to 0.60 mm. In consideration of the smooth movement of the guide wire 11 and the radiation wire 7, the lumen and these guide wires 1
1. Appropriate clearance between the radiation wire 7 is required. This suitable clearance is approximately 0.03 mm. Therefore, the inner diameter of the guide wire is 0.42.
mm, and the inner diameter of the radiation wire is 0.61 mm when the outer diameter of the radiation wire 7 is 0.55 mm. In this case, the sum of the two lumen diameters is 0.42 m
m + 0.61 mm = 1.03 mm. The outer diameter of the intravascular radiation irradiation catheter 8 is determined by the total of these two lumens and the three wall thicknesses existing around the lumen (FIG. 2). It is said that at least 0.08 mm is required as this thickness, and since there are three such thicknesses, a total of 0.08 mm is required.
08 mm X 3 = 0.24 mm is required as the wall thickness. After all, the outer diameter of the intravascular irradiation catheter 8 is 1.03 mm + 0.24 mm = 1.27 m.
m, which is a very large outer diameter. Further, when a balloon for a centering function described later or a balloon for PTCA (angioplasty) is added, one more balloon is provided in the catheter shaft.
First, a lumen for expanding the balloon is required, and in this case, the outer diameter of the catheter is further increased. This can be a major problem when guiding a catheter into a coronary artery.

[0011]

SUMMARY OF THE INVENTION In order to prevent restenosis of a blood vessel, particularly a coronary artery, the present invention irradiates radiation to a stenosis affected area after performing (coronary) artery angioplasty (PTCA or PTA). Irradiation catheter
It is to eliminate the above-mentioned problems. That is, a guide wire commonly used in (coronary) angioplasty (PTCA, PTA) can be used, and the radiation wire does not enter the blood vessel, so that the radiation source can be prevented from coming into contact with blood. Another object of the present invention is to provide an intravascular irradiation catheter having a small diameter and excellent operability.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a radiation irradiation catheter of the present invention is characterized in that, in an intravascular radiation irradiation catheter, the lumen through which the guide wire passes and the lumen through which the radiation wire passes are the same. In other words,
Also, by reducing the diameter near the distal end of the lumen and making the inner diameter at the smallest point larger than the outer diameter of the guide wire but smaller than the outer diameter of the radiation wire, the guide wire is , And the radiation wire is prevented from moving into the blood vessel near the distal end of the lumen.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments according to the present invention will be described below in detail with reference to the drawings.

[0014]

(Embodiment 1) An embodiment of the present invention will be described with reference to FIG. In this example, a coronary artery intravascular irradiation catheter was manufactured. The catheter 12 includes a shaft having one lumen and a manifold 27, and the distal end 17 of the shaft is reduced in diameter toward the distal side. The shaft is composed of a distal shaft 14 and a proximal shaft 15 and is joined at a transition portion 16 by heat welding or bonding with an adhesive.

Hereinafter, a detailed manufacturing and assembling method will be described. First, as the distal shaft 14, outer diameter / inner diameter = 0.80
A mm / 0.60 mm high-density polyethylene tube was manufactured by extrusion. This is shown in FIG.
ia_tip, Dia_mid, Dia_GW, Dia
The tip is reduced by the method shown in FIG. 6 so that _rad satisfies the following relational expressions.

In FIG. 5, Dia_tip is the diameter of the smallest diameter portion after the distal end of the distal shaft 14 is reduced,
ia_mid is a portion other than the distal end of the distal shaft 14, that is, the diameter on the proximal side (original diameter of the distal shaft tube), and Dia_GW is the outer diameter of the guide wire, P
Dia_ is typically 0.36 mm for TCA.
rad is the outer diameter of the radiation wire, which was 0.55 mm this time.

Regarding these diameter sizes, Dia_ra
d> Dia_GW, Dia_rad <Dia_
mid, Dia_GW <Dia_tip <Di
The size of the radiation wire, the inner diameter of the catheter, and the inner diameter of the tip were determined so as to satisfy a_rad. Since the outer diameter (Dia_GW) of the guide wire is 0.36 mm and the outer diameter (Dia_rad) of the radiation wire is 0.55 mm, the condition of Dia_rad> Dia_GW is satisfied.

Next, the extruded distal shaft 14
Dia_mid of Dia_rad (0.55
mm).
_Mid was set to 0.60 mm. The minimum diameter of the tip portion (Dia_tip) is larger than 0.36 mm which is the outer diameter of the guide wire (Dia_GW), and the outer diameter of the radiation wire (Dia_rad) is 0.3 mm.
In order to be smaller than 55 mm, Dia_tip =
0.42 mm. As a method for reducing the diameter of the distal end of the distal shaft 14, as shown in FIG. 6, a core material 18 having a tapered portion 19 having an outer diameter profile equal to a desired reduced diameter shape, and a heat-shrinkable tube 21 are prepared. I do. Although the heat-shrinkable tube used this time is made of polyolefin, it is obvious to those skilled in the art that a tube of polytetrafluoroethylene, EVA, polyethylene or the like can be used.

The core 18 has the above-described tapered portion 19 and large-diameter portions Dia_B and small-diameter portions Dia_A on both sides thereof.
It is preferable that the portion having the diameter Dia_B is at least as long as the length of the distal shaft. The diameter of Dia_B is 0.01 from the inner diameter Dia_mid of the distal shaft.
It is preferable that the diameter is smaller by about 0 mm to 0.015 mm. D
ia_A is set to the smallest diameter of the reduced diameter portion at the distal end of the distal shaft. The high-density polyethylene tube made by the above extrusion molding is about 27c
6 m, a core material is passed therethrough, and the tapered portion is accurately positioned at the distal end of the high-density polyethylene tube as shown in FIG. The heat shrink tube 21 is arranged. Next, hot air is blown from the outside of the heat-shrinkable tube as shown by an arrow 22 in FIG. By doing so, the heat-shrinkable tube shrinks, and at the same time, the distal end of the tube serving as the distal shaft inside the tube is thermally deformed, and as a result, the diameter can be reduced. After this, the heat shrink tubing is carefully peeled off, and then the core is pulled out of the tube.
In order to facilitate this drawing operation, it is desirable that the core material is previously coated with polytetrafluoroethylene or the like.

Depending on the result of the reduction in the diameter of the distal end of the distal shaft, it is necessary to trim the leading end (removing unnecessary parts finely so as to obtain a clean shape). Thus, the distal shaft of the present invention as shown in FIG. 6C is completed. Note that the reduced diameter shape is not limited to the shape shown in FIG. 6, and the outer diameter may not be reduced but only the inner diameter may be reduced as shown in FIG. 7.

Next, a tube made of nylon 12 having an outer diameter / inner diameter of 0.82 mm / 0.62 mm was manufactured as the proximal shaft 15 by extrusion molding. This was adhesively bonded to the above-mentioned distal shaft 14 at the transition portion 16 using a polyurethane adhesive. Thereafter, the radiopaque ring marker 23 was fixed with an adhesive near the distal end of the distal shaft so that the position of the distal end of the catheter could be confirmed under fluoroscopy. Loct as this adhesive
"401" which is a cyanoacrylate-based adhesive manufactured by ITE
1 "was used.

Next, the proximal end of the proximal shaft 15 was adhered to the lumen of the manifold 18. This time also Loc
An adhesive “4011” manufactured by Tite was used. Thus, as shown in FIG. 4B, the guide wire 11
Although it is possible to penetrate the distal end of the catheter 12 and go further forward, that is, distally (the distal side of the blood vessel),
As shown in (c), the radiation wire 7 cannot pass through the reduced diameter portion 17 of the distal end of the catheter, and is prevented from moving. The outer diameter of the catheter is 0.80m on the distal side.
m, a very small diameter of 0.82 mm on the proximal side, and it is possible to construct a catheter excellent in operability even in a small-diameter, highly bent blood vessel such as a coronary artery.

The method of using the first embodiment is as follows. P with PTCA balloon catheter or stent
The TCA procedure (angioplasty) is completed, and a guide wire remains in the coronary artery. In this state, the intravascular irradiation catheter 12 of this embodiment is advanced along the guide wire (the guide wire 11 passes through the lumen 13) to reach the lesion. The operation at this time is performed under X-ray fluoroscopy. At this time, it is confirmed by using two sets of X-ray opaque ring markers that the stenosis affected area is positioned. Thereafter, the guide wire 11 is pulled out of the body, and instead, the radiation wire 7 is advanced toward the distal side of the lumen of the intravascular irradiation catheter to position the radiation source 4 at the stenosis affected part. At this time, X
A radiopaque ring marker is disposed, and the radiopaque ring marker 2 of the above-described intravascular radiation irradiation catheter 12 is provided.
It would be advantageous if the alignment with (3) could be performed. In this state, radiation is irradiated from the radiation source for a required time (FIG. 10C). Before inserting the actual radiation wire 7, use a dummy radiation wire (a simple wire having no ability to emit radiation and the same size, axial strength, etc. as the actual radiation wire) to irradiate intravascular radiation. It is preferable to confirm in advance that the catheter can be guided to the distal side in the catheter. When irradiation is completed, the radiation wire 7 is collected outside the body, and the intravascular irradiation catheter is collected outside the body.

(Embodiment 2) Another embodiment will be described with reference to FIGS. In this embodiment, the technology of the present invention is applied to a PTCA balloon catheter or an intravascular irradiation catheter with a center ring, and a balloon is provided at the tip of the catheter. This balloon uses PTC
The A balloon catheter is used for dilating a coronary stenosis, and the centering intravascular radiation irradiation catheter is used for centering. The centering is a function for positioning the radiation source at the center of the cross section at the stenosis. Recently, the need for uniform irradiation of the blood vessel wall has been widely recognized, and this function has become important. Regarding uniform irradiation of the blood vessel wall, when the radiation source is located at a lesion in the blood vessel and is offset from the center in the cross section of the blood vessel, the blood vessel wall that is too close to the radiation source receives excessive irradiation and necrosis of the blood vessel , Resulting in aneurysms and the like.

Conversely, a sufficient amount of radiation to suppress the growth of smooth muscle does not reach the blood vessel wall far from the radiation source. This is because the energy of the radiation emitted from the radiation source drops sharply with distance from the radiation source. This is said to be particularly significant when the radiation used is β-rays. With the balloon catheter of this embodiment, the function of expanding the stenosis portion of the PTCA balloon catheter and the above-mentioned intravascular radiation irradiation function (with a centering function) can be used. It can be used for both purposes, for intravascular radiation irradiation (with centering function) after completion. The catheter which is used for both functions is a catheter which has both PTCA (angioplasty) function and radiation irradiation function simultaneously. One catheter has the great merit that stenosis dilation and radiotherapy can be performed in a short time. is there.

A method of manufacturing and assembling the catheter according to the second embodiment shown in FIG. 8 will be described below. The present embodiment is a catheter having a so-called coaxial shaft structure composed of an inner tube and an outer tube, and having a balloon at the tip. The distal shaft 14 of which the diameter is reduced in the distal end made in the first embodiment.
To the distal inner tube, the proximal shaft 15 to the proximal inner tube, and the two were joined at a transition portion (not shown in FIG. 8). However, in this example, the material of the proximal inner tube was the same as the high-density polyethylene of the material of the distal inner tube. The reason for this is to reduce friction with the guide wire 11 and the radiation wire 7 passing through the inside. Nylon 1 for proximal inner tube
By using high-density polyethylene instead of 2, the axial strength (hardness to bend) of the inner tube is reduced. However, in the case of the present embodiment, a tube is further arranged on the outside due to the coaxial structure, and the outer tube is used. Since the axial strength is maintained,
No problem. In addition, Example 1 was used as a joining method of the transition portion.
The method described in was used. The X-ray opaque ring marker was also fixed by the above-mentioned method.

Regarding the outer tube, the distal tube and the proximal tube
Segment, and the distal outer tube has an outer diameter /
PEBAX (ATOCHEM 70, a polyamide block copolymer having an inner diameter of 1.08 mm / 0.92 mm)
33SA01) tube (approximately 24 cm long) and the proximal outer tube used was a polyimide tube (approximately 105 cm long) having an outer diameter / inner diameter of 1.10 mm / 0.96 mm. These two tubes were adhesively bonded at the transition (not shown) in the same manner as described above. The materials of the inner tube and the outer tube are not limited to the above materials, and various materials such as polyethylene, polyolefin, polyamide, polyester, polyurethane, their elastomers, and blends thereof can be used.

Thereafter, a balloon made by blow molding (described later) is bonded to both the distal end of the distal outer tube and the distal end of the distal inner tube as shown in FIG. did. A polyurethane adhesive was used for this bonding. Thereafter, the proximal end of the proximal outer tube and the proximal end of the proximal inner tube were adhesively bonded to the manifold 27. This allows the guide wire 11 and the radiation wire 7 to pass through the straight port of the manifold and then pass through the inner tube toward the distal side. From the other port of the manifold, a high-pressure contrast medium, physiological saline, or a liquid mixture thereof is injected by a device called a syringe or an indeflator. These high-pressure liquids flow through the clearance between the outer tube and the inner tube, connect to the balloon, and are used to expand and contract the balloon.

Using a polyester elastomer Hytrel (manufactured by DuPont) as a material for the balloon, a tube having an outer diameter / inner diameter of 0.86 mm / 0.43 mm was extruded. This is disclosed in JP-A-63-1
Uniaxial stretching or biaxial stretching is performed by blow molding as described in JP-A-83070 or JP-A-3-57462. As a result, the size of the balloon straight tube after molding has an outer diameter of φ2.980 mm when a pressure of 6 atm is applied,
The inner diameter became 2.935 mm. As a material of the balloon, polyester, polyamide, polyamide elastomer, polyurethane, polyolefin, polyethylene, or the like may be used in addition to the polyester elastomer.

As a more detailed blow molding condition, the outer diameter / inner diameter is φ0.86 mm /
First, a tube having a diameter of 0.43 mm and a length of 25 cm is stretched about 4.8 times in the axial direction at room temperature. After that, the stretched tube is set in a mold having a cavity having the same shape as the desired balloon shape, one end is plugged, and the other side is connected to a high-pressure air source. In this state, the temperature of the mold was set to 82 ° C., and air of 20 atm was added to the inside of the tube to form a balloon. Thereafter, in order to improve the dimensional stability of the balloon, the air pressure was set to 14 atm, the temperature of the mold was raised to 95 ° C., and heat treatment was performed for 2 minutes.

When the vascular dilatation using the PTCA balloon catheter has already been completed according to this embodiment, the catheter can be used as an intravascular irradiation catheter with a centering function. This is shown in FIG. In other words, the balloon-equipped catheter shown in FIG. 10A is advanced along the guide wire 11 which has already passed through the stenosis affected part with the balloon deflated, and the balloon is arranged at the stenosis affected part. In this state, the balloon is expanded for centering (FIG. 10B). Then, the guide wire 11 is pulled out of the body, and instead, the radiation wire 7 is advanced toward the distal side inside the intravascular irradiation catheter, and the radiation source 4 is positioned at the stenosis affected part. Radiation is applied from the radiation source for the time indicated by (c) in FIG. Before inserting the actual radiation wire 7, use a dummy radiation wire (a simple wire having no ability to emit radiation and the same size, axial strength, etc. as the actual radiation wire) to irradiate intravascular radiation. It is preferable to confirm in advance that the catheter can be guided to the distal side in the catheter.

When the PTCA balloon catheter and the intravascular irradiation catheter with centering are used together, the guidewire 11 is passed through the catheter with balloon shown in FIG. In the contracted state, it is guided into the coronary artery together with the guide wire. And the guide wire 11
Is guided through the stenosis, and the balloon is guided until it is placed at the stenosis (FIG. 10A). In this state, the balloon is expanded to widen the stenosis (FIG. 10B). The balloon is deflated and the extent of the stenosis expanded is checked under fluoroscopy. If the stenosis has been sufficiently expanded, then the balloon is expanded again at the stenosis affected part for centering at the time of irradiation, and in this state, the guide wire 11 is pulled out. The radiation source 4 is moved toward the distal side of the internal radiation irradiation catheter, and the radiation source 4 is positioned at the affected part of the stenosis. In this state, radiation is emitted from the radiation source for a required time. In this case, it is easy to use the alignment of the radiopaque ring markers. Before inserting the actual radiation wire 7,
A dummy radiation wire (a simple wire without the ability to emit radiation, the same size, axial strength, etc. as the actual radiation wire) can be guided to the distal side inside the intravascular irradiation catheter. It is preferable to confirm.

According to this embodiment, the guide wire 11 penetrates the distal end of the catheter and can go further forward, that is, to the distal side (peripheral side of the blood vessel). Cannot pass through the reduced diameter portion 17 of the tip, and the movement is blocked. In addition, the catheter has a very small outer diameter of 1.08 mm on the distal side and 1.10 mm on the proximal side, making it possible to construct a catheter with excellent operability even in a small-diameter, highly bent blood vessel such as a coronary artery. Alternatively, it is a high value-added catheter having a balloon for centering at the time of intravascular irradiation.

The guide wire 11 and the radiation wire 7
The reduced diameter portion near the distal end of the lumen through which the gas passes (not only the distal end) is not limited to the tip end, but may be reduced wherever it is desired to stop the passage of the radiation wire. For example, as shown in FIG. 9, the diameter may be reduced slightly on the proximal side of the proximal portion of the balloon. In this case, the balloon itself is used for a PTCA procedure (angioplasty), i.e., to dilate the stenosis, and then is deflated, causing the intravascular irradiation catheter to move more distally of the vessel, and then The radiation wire is guided to the stenosis just expanded, and irradiation is performed there. In this case, the balloon does not work as a centering function. In particular, in the case of γ-rays among radiations, centering may not be necessary in some cases because the radiation has a large transmission and reachability, and is effective in such a case.

Although the present invention and its embodiments have been described above, the technology of the present invention can be applied to many variations or other uses other than the above description. In the second embodiment, the type in which the shaft structure has a coaxial structure of the inner tube and the outer tube has been described. However, the shaft structure is not a coaxial structure, but a dual-purpose lumen tube through which the guide wire 11 and the radiation wire 7 pass, and a balloon. A shaft configuration is also possible in which the expanding tubes through which the high-pressure liquid to be expanded flows are arranged adjacent to each other.

In this embodiment, the inside of the entire length of the catheter from the manifold to the distal end is of a type called an over-the-wire type in which a guide wire 11 passes. It will be apparent to those skilled in the art that the present invention can also be applied to a monorail type that passes only.

If the balloon is inflated for a long time in the coronary artery, the supply of blood to the peripheral side is cut off, causing great pain to the patient. However, even if the balloon is extended for a long time, the patient is not hurt. Perfusion function for, that is,
During balloon dilatation in the coronary artery, via the inside of the catheter,
It is also possible to have a function of supplying blood from the proximal side to the distal side of the balloon.

In this embodiment, an intravascular irradiation therapy catheter for preventing coronary artery restenosis has been described. However, it is apparent to those skilled in the art that the present invention can be applied to peripheral blood vessels other than coronary arteries and dialysis shunt restenosis. .

In addition to using a catheter other than an intravascular irradiation therapy catheter, that is, a guide wire,
It will be apparent to those skilled in the art that the present invention can be used for a long object having a certain function that needs to be kept out of the distal end of the catheter.

In this embodiment, only the balloons shown in FIGS. 8, 9 and 10 are shown as means for performing the centering function. However, it is understood by those skilled in the art that the present invention can be applied to other means. Is obvious.

In this embodiment, the radiation wire has a long shape having a plurality of radiation sources at the distal portion. However, the radiation wire is generally a long shape including a means capable of irradiating radiation. Anything is fine.

[0042]

According to the present invention, the intravascular radiation irradiation catheter of the present invention has a sufficiently small diameter even in a blood vessel having a small diameter and severe bending, such as a coronary artery, so that there is no problem in operability during guidance. In addition, the use of a guide wire is essential when treating a tortuous blood vessel such as a coronary artery, or a blood vessel with many branches, but a guide wire can be used as before, and a small-diameter intravascular irradiation is also possible. A catheter is feasible. In addition, a radiation wire having a radiation source such as an isotope
Since the radiation source does not enter the blood vessel, the risk of the radiation source coming into contact with blood due to breakage of the radiation wire due to contact with the blood vessel wall or the like can be eliminated.

[Brief description of the drawings]

FIG. 1 is an embodiment of US Pat. No. 5,199,939.

FIG. 2 is an embodiment of Japanese Patent Publication No. 9-508038.

FIG. 3 Example of Japanese Patent Publication No. 9-508038 (actual use in a blood vessel)

4A and 4B show an embodiment of the present invention. FIG. 4A is an axial sectional view of the intravascular radiation irradiation catheter of the present embodiment, and FIG. 4B is a diagram showing a guide wire passing through the intravascular radiation irradiation catheter of the present embodiment. (C) is an axial cross-sectional view when a radiation wire is guided into the intravascular radiation irradiation catheter of the present embodiment.

FIG. 5 shows the diameters of the guide wire, the radiation wire and the intravascular radiation irradiation catheter which are important in the present invention. FIG. 5 (a) is the diameter of the intravascular radiation irradiation catheter of this embodiment, and FIG. , (C) shows the diameter of the radiation wire.

6A and 6B show a method of manufacturing the intravascular radiation irradiation catheter described in the embodiment of the present invention. FIG. 6A shows a state where a core material and a heat-shrinkable tube are arranged, and FIG. 6B shows a state where the heat-shrinkable tube is shrunk. (C) shows the shape of the molded intravascular radiation irradiation catheter, respectively.

FIG. 7 shows different reduced diameter shapes of an embodiment of the present invention.

FIG. 8 shows another embodiment (with balloon) of the present invention.
(A) is an axial cross-sectional view of an intravascular radiation irradiation catheter with a balloon of the present embodiment, (b) is an axial cross-sectional view when a guidewire passes through the intravascular radiation irradiation catheter with a balloon of the present embodiment, (C) is an axial cross-sectional view when a radiation wire is guided into the intravascular radiation irradiation catheter with a balloon according to the present embodiment.

FIG. 9 shows another embodiment of the present invention (with a balloon) in which the reduced diameter portion is different. (A) is an axial cross-sectional view of an intravascular radiation irradiation catheter with a balloon of this embodiment, and (b) is an axial cross-sectional view when a radiation wire is guided into the intravascular radiation irradiation catheter with a balloon of this embodiment. Is shown.

FIG. 10 illustrates another embodiment (with balloon) of the present invention being used in a blood vessel. (A) is an axial cross-sectional view of the intravascular radiation irradiation catheter of the present embodiment at the time of balloon deflation positioned on the guide wire and in the blood vessel,
(B) is an axial cross-sectional view of the intravascular radiation irradiation catheter of the present embodiment in a state where the balloon is expanded from the state of (a), and (c) is a state where a radiation wire is guided from the state of (b) to emit radiation. The axial cross-sectional view of the intravascular radiation irradiation catheter at the time of irradiating is shown, respectively.

[Explanation of symbols]

Reference Signs List 1 lumen of probing catheter 2 conventional intravascular irradiation catheter (probing catheter) 3 lesion site (stenosis) 4 radiation source 5 spacer 6 covering tube 7 radiation wire 8 another conventional intravascular irradiation catheter 9 guide The lumen through which the wire passes 10 The lumen through which the radiation wire passes 11 The guide wire 12 The intravascular irradiation catheter of the embodiment of the present invention 13 The guide wire, the lumen through which the radiation wire passes 14 The distal shaft 15 The proximal shaft 16 Transition part 17 Reduced diameter portion near tip 18 Core material 19 Tapered portion of core material 20 Small diameter portion of core material 21 Heat shrink tube 22 Hot air added to heat shrink tube 23 X-ray opaque ring marker 24 Distal outer tube 25 Proximal Outer tube 26 Balloon 27 Manifold

Claims (2)

[Claims] An intravascular irradiation catheter for preventing restenosis, which is used together with a guide wire for angioplasty and an elongated radiation wire having a radiation source at a distal portion larger than an outer diameter thereof. At least one shaft tube extending near a distal end through which the wire or the guide wire passes, and having an inner diameter larger than an outer diameter of the guide wire near a distal end portion of the shaft tube, and By reducing the diameter to a size smaller than the outer diameter of the distal end of the wire, the guide wire penetrates further distally beyond the distal end of the shaft tube, but does not penetrate the radiation wire. Characterized intravascular irradiation catheter. 2. The intravascular radiation irradiation catheter according to claim 1, further comprising a function for centering the radiation source.