JP2004298269A - Catheter and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a catheter having a stainless steel cylindrical shaft formed with a solid lubricant layer on a peripheral surface, wherein the cylindrical shaft does not gather rust easily. <P>SOLUTION: The catheter 10 is produced to have a fluorocarbon resin based solid lubricant layer 5 on the peripheral surface of the stainless steel cylindrical shaft 1, wherein the above peripheral surface is coated with the material for the above solid lubricant layer, and the above material is treated with heat of 340°C or lower. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０１０２】
表１から明らかなように、また、図７〜図１０と図１１との対比から明らかなように、フッ素樹脂系の固体潤滑剤層を形成する際の熱処理温度を３４０℃以下にすることにより、ステンレス鋼製の管状シャフトの耐食性の低下を抑制することができ、その結果として、カテーテル（管状シャフト）の内周面での錆の発生を抑制することができる。
【０１０３】
【発明の効果】
以上説明したように、本発明によれば、ステンレス鋼製の管状シャフトの外周面にフッ素樹脂系の固体潤滑剤層を形成しても管状シャフトでの錆の発生が抑制されるので、体腔内や血管内への挿入が容易で、しかも、長期亘って安全性を高く維持することが容易なカテーテルを提供することが可能になる。
【図面の簡単な説明】
【図１】図１（Ａ）は、第１実施形態のカテーテルを真っ直ぐにしたときの状態を示す概略図であり、図１（Ｂ）は、図１（Ａ）に示したカテーテルをその長手軸を含む面で切ったときの断面の概略図であり、図１（Ｃ）は、図１（Ａ）に示したカテーテルをその長手軸を法線とする面で切ったときの断面の概略図である。
【図２】図２（Ａ）〜図２（Ｃ）は、それぞれ別個に、本発明のカテーテルに係る変形例を部分的に切欠いて示す概略図である。
【図３】図３（Ａ）〜図３（Ｃ）は、それぞれ別個に、本発明のカテーテルに係る他の変形例を部分的に切欠いて示す概略図である。
【図４】図４（Ａ）は、第２実施形態のカテーテルを真っ直ぐにしたときの状態を示す概略図であり、図４（Ｂ）は、図４（Ａ）に示したカテーテルの断面を部分的に示す概略図である。
【図５】図５（Ａ）〜図５（Ｃ）は、それぞれ別個に、本発明のカテーテルに係る他の変形例を示す概略図である。
【図６】図６（Ａ）〜図６（Ｃ）は、それぞれ別個に、本発明のカテーテルに係る他の変形例を示す概略図である。
【図７】実施例１のカテーテルから得たサンプルの耐食試験前後の状態を示す図面代用写真である。
【図８】実施例２のカテーテルから得たサンプルの耐食試験前後の状態を示す図面代用写真である。
【図９】実施例３のカテーテルから得たサンプルの耐食試験前後の状態を示す図面代用写真である。
【図１０】実施例４のカテーテルから得たサンプルの耐食試験前後の状態を示す図面代用写真である。
【図１１】比較例のカテーテルから得たサンプルの耐食試験前後の状態を示す図面代用写真である。
【符号の説明】
１、１Ａ〜１Ｆ ステンレス鋼製の管状シャフト
５、５Ａ〜５Ｆ フッ素樹脂系の固体潤滑剤層
１０、１５Ａ〜１５Ｆ、１８Ａ〜１８Ｆ カテーテル（ハイポチューブ）
３０ ディスタールシャフト
４０ バルーン
７０ 血管拡張用バルーンカテーテル[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a catheter and a method for manufacturing the same.
[0002]
[Prior art]
In recent years, medical care has tended toward less invasive treatments in order to minimize the burden on the patient's body. For example, ischemic heart disease is increasingly being treated using a vasodilating balloon catheter instead of previous coronary artery bypass surgery.
[0003]
A catheter is a small-diameter tube that is inserted into the body for injecting a drug solution or draining a body fluid.A balloon catheter is used to expand a stenotic part of a blood vessel and restore blood flow, or at the tip of the catheter. A balloon capable of controlling inflation and deflation is attached to the distal end portion so as to stably place the portion in the body.
[0004]
Catheter treatment or testing is increasingly applicable because it is less invasive than open surgery. Today, in addition to vascular dilatation balloon catheters, various types of catheters have been developed in accordance with applications, such as IABP (intra-aortic balloon pumping) balloon catheters, thermodilution balloon catheters, and temporary pacing catheters.
[0005]
Each of these catheters has a tubular shaft. As one method for improving the insertability of a catheter into a patient's body cavity or blood vessel, the tubular shaft is made of metal so that the tubular shaft has a certain degree of flexibility and a certain degree of rigidity. It is known to
[0006]
Since a metal tubular shaft is required to have a small diameter and to have no seams, the tubular shaft is often manufactured by cold drawing. For this reason, austenitic stainless steel (for example, SUS304) excellent in cold drawability is often used as the material.
[0007]
When the tubular shaft is made of metal, the outer peripheral surface of the tubular shaft is made of polytetrafluoroethylene (hereinafter, abbreviated as “PTFE”), as described in the upper left column of page 6 of Patent Document 1, for example. ) To reduce the friction that occurs between the patient's tissue and the tubular shaft when inserting the catheter.
[0008]
[Patent Document 1]
JP-A-2-277465
[0009]
[Problems to be solved by the invention]
The stainless steel tubular shaft having the PTFE layer formed on the outer peripheral surface as described above is preferable in that friction generated between the stainless steel shaft and the patient's tissue is small. There is a tendency that rust is easily generated inside as compared with a stainless steel tubular shaft that is not formed.
[0010]
For example, if rust is present in the tubular shaft of a catheter inserted into the body for injecting a drug solution or discharging a body fluid, there is a risk that the rust may enter the patient's body and have a serious adverse effect. In addition, for example, in a balloon catheter for vasodilation, since high pressure is applied inside the balloon to expand a stenotic part of a blood vessel, the balloon may be ruptured in some cases, and rust is generated in the tubular shaft. If the balloon ruptures, there is a risk that the rust will flow into the blood vessel and cause a thrombus, which may have a serious adverse effect on the patient.
[0011]
Therefore, an object of the present invention is to provide a catheter having a stainless steel tubular shaft having a solid lubricant layer formed on an outer peripheral surface thereof and in which rust does not easily occur on the tubular shaft.
[0012]
[Means for Solving the Problems]
The present inventors, in order to achieve the above object, the relationship between processing conditions when forming a fluororesin-based solid lubricant layer on the outer peripheral surface of a stainless steel tubular shaft and rust generated in the tubular shaft As a result of intensive studies, it has been found that the generation of rust can be prevented by setting the heat treatment temperature at the time of forming the solid lubricant layer to a predetermined temperature or lower, and this finding has led to the completion of the present invention.
[0013]
Thus, according to the first aspect of the present invention, it has a stainless steel tubular shaft and a fluororesin-based solid lubricant layer formed on the outer peripheral surface of the tubular shaft, wherein the solid lubricant layer is And a catheter formed by coating the material of the solid lubricant layer on the outer peripheral surface and then heat-treating the material at 340 ° C. or lower.
[0014]
The tubular shaft is preferably made of austenitic stainless steel.
[0015]
The material preferably contains a binder resin having a relatively low melting point and a fluorine-based resin having a relatively high melting point.
[0016]
In the catheter of the present invention, the material is preferably heat-treated at 200 to 340 ° C.
[0017]
The catheter of the present invention may be a balloon catheter in which one end of a flexible distal shaft is connected to one end of the tubular shaft, and a balloon is connected to the other end of the distal shaft.
[0018]
According to a second aspect of the present invention, a first step of preparing a stainless steel tubular shaft, and coating a material capable of forming a fluororesin-based solid lubricant layer on the outer peripheral surface of the tubular shaft And a third step of heat-treating the material at 340 ° C. or lower to form the fluororesin-based solid lubricant layer on the outer peripheral surface of the tubular shaft. You.
[0019]
The tubular shaft prepared in the first step is preferably made of austenitic stainless steel.
[0020]
It is preferable that the material used in the second step includes a binder resin having a relatively low melting point and a fluorine-based resin having a relatively high melting point.
[0021]
In the third step, the material is preferably heat-treated at 200 to 340 ° C.
[0022]
The method of manufacturing a catheter according to the present invention includes a fourth step of connecting one end of a flexible distal shaft to one end of the tubular shaft that has undergone the third step, and a balloon at the other end of the distal shaft. And a fifth step of connecting.
[0023]
[Action]
By setting the heat treatment temperature at the time of forming the solid lubricant layer on the outer peripheral surface of the stainless steel tubular shaft to 340 ° C. or less, it is possible to suppress the occurrence of rust on the tubular shaft. Although the reason is not clear, it is considered that rust is prevented from being generated as a result of suppressing the decrease in the corrosion resistance of the tubular shaft due to the heat treatment at the time of forming the solid lubricant layer.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0025]
<First embodiment according to the catheter of the present invention>
1 (A), 1 (B), and 1 (C) schematically show a first embodiment of the catheter of the present invention. FIG. 1A schematically shows a state in which the catheter 10 of the present embodiment is straightened, and FIG. 1B shows a state in which the catheter 10 shown in FIG. (The same applies to the longitudinal axis in a straightened state. The same applies to the following.) FIG. 1 (C) schematically shows a cross section when cut along a plane including the catheter 10 shown in FIG. 1 (A). Fig. 2 schematically shows a cross section taken along a plane having a longitudinal axis as a normal line.
[0026]
As shown in these figures, the catheter 10 of the first embodiment has a tubular shaft 1 made of stainless steel and a fluororesin-based solid lubricant layer 5 formed on the entire outer peripheral surface of the tubular shaft 1. are doing.
[0027]
The tubular shaft 1 has a shape in which both ends in the longitudinal direction are cut along a plane whose normal line is the longitudinal axis of the tubular shaft 1 (meaning the longitudinal axis when the tubular shaft is straightened; the same applies to the following description). It is a tubular object exhibiting As the material of the tubular shaft, an austenitic stainless steel is preferable among stainless steels, and SUS304 is particularly preferable in terms of excellent cold drawability and excellent corrosion resistance.
[0028]
Since the tubular shaft 1 is inserted into a body cavity or a blood vessel of a patient, the tubular shaft 1 has a certain rigidity so that the pushing force of the operator is transmitted to the distal end portion at the time of insertion. On the other hand, it is necessary to have a certain degree of flexibility so that tissues and blood vessels of a patient are not damaged during insertion. Therefore, the shape and size of the tubular shaft 1 are appropriately selected according to the material thereof, the use of the catheter 10, and the like.
[0029]
For example, when austenitic stainless steel such as SUS304 is used as the material of the tubular shaft 1 and the catheter 10 is used as a component (hypotube) of a vascular dilatation balloon catheter, the outer diameter of the tubular shaft 1 Can be approximately in the range of 0.5 to 3.0 mm, preferably approximately in the range of 0.5 to 1.0 mm, and the inner diameter thereof is approximately in the range of 0.3 to 2.8 mm, preferably , Approximately within the range of 0.3 to 0.8 mm. The length of the tubular shaft 1 at this time is appropriately selected according to the use of the vascular dilatation balloon catheter.
[0030]
The vascular dilatation balloon catheter is used for percutaneous coronary angioplasty (PTCA), dilation of a blood vessel such as a limb, or renal vasodilation. Examples of balloon catheters other than those for vasodilation include those used for dilation of the upper ureter and the like.
[0031]
The fluororesin-based solid lubricant layer 5 formed on the outer peripheral surface of the tubular shaft 1 inserts a catheter 10 or a long catheter using the catheter 10 as a hypotube into a body cavity or a blood vessel of a patient. In this case, the friction between the tubular shaft 1 and the inner surface of the guide catheter is reduced when a guide catheter is used. It is fixed to the outer peripheral surface.
[0032]
The thickness of the solid lubricant layer 5 varies depending on the type (use) and thickness of the catheter 10, the friction characteristics required for the catheter 10, and the like, but is generally appropriately selected within a range of about 5 to 20 μm. It is more preferable to appropriately select the thickness within a range of about 5 to 15 μm. Further, in the present embodiment, the solid lubricant layer 5 is formed on the entire outer peripheral surface of the tubular shaft 1, but the solid lubricant layer 5 does not necessarily need to be formed on the entire outer peripheral surface, and is inserted into the body, for example. The solid lubricant layer 5 may be formed only on the portion.
[0033]
As the material of the solid lubricant layer 5, from the viewpoint that the obtained solid lubricant layer has a small coefficient of friction, and from the viewpoint of being fixed to the outer peripheral surface of the tubular shaft 1 by heat treatment at 340 ° C. or less, (1) Fluororesins such as polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE) and polyvinylidene fluoride (PVDF); (2) tetrafluoroethylene-hexafluoropropylene copolymer (FEP); Fluororesins such as fluoroalkyl vinyl ether copolymer (PFA), ethylene-tetrafluoroethylene copolymer (ETFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), and fluoroethylene-alkyl vinyl ether copolymer (FEVE) System copolymer Is a binder resin (3) having a melting point lower than that of the fluororesin or the fluororesin-based copolymer and soluble in a solvent (for example, an epoxy resin or a polyamideimide resin). Or the like), it is preferable to use a modified fluororesin (including a paint containing the modified fluororesin) solubilized in a solvent by adding the same.
[0034]
Among these materials for the solid lubricant layer 5, it is more preferable to use PTFE, PFA, FEP, or the like having a lower coefficient of friction, and a solid lubricant layer that is uniform and excellent in lubricity even by heat treatment at a relatively low temperature. It is particularly preferable to use FEP which is easily formed or contains FEP.
[0035]
The form of the above material can be various forms such as solventless powder, aqueous dispersion, organic solvent dispersion, aqueous modified fluorine paint, organic solvent modified fluorine paint, organosol paint and the like. From the viewpoint that the target solid lubricant layer 5 is easily formed by heat treatment at a relatively low temperature, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, or the like is used as an organic solvent, and an epoxy resin is used as a binder resin in an amount of 10 to 40 wt. % Of an organic solvent-based modified fluorine paint is preferably used.
[0036]
The above materials, if necessary, such as a curing agent, a pigment, a flow regulator, an antioxidant, a thermal degradation inhibitor, an ultraviolet absorber, a foam inhibitor, a gloss regulator, a defoamer, an antistatic agent, Various additives can be blended.
[0037]
Note that a method for forming the solid lubricant layer 5 will be described in detail in an embodiment described below relating to the method for manufacturing a catheter of the present invention.
[0038]
In the catheter 10 having the tubular shaft 1 and the solid lubricant layer 5 described above, the heat treatment temperature when forming the solid lubricant layer 5 is higher than 340 ° C. in the inner peripheral surface of the tubular shaft 1. The generation of rust is suppressed. It is considered that this is because, by setting the above heat treatment temperature to 340 ° C. or less, a decrease in the corrosion resistance of the tubular shaft 1 due to the heat treatment is suppressed.
[0039]
<Modifications 1 to 6 according to catheter of the present invention>
2 (A) to 2 (C) and FIGS. 3 (A) to 3 (C) separately show modifications of the catheter according to the present invention, in particular, one component (hypotube) of a long catheter. 1 is a schematic view showing a catheter suitable for use as a tube, partially cut away.
[0040]
The catheters 15A to 15F of Modifications 1 to 6 shown in these drawings have low rigidity regions 2A to 2F having relatively low bending rigidity formed at one end in the longitudinal direction. And different. However, these catheters 15A to 15F differ from the catheters 10 of the first embodiment in that a fluororesin-based solid lubricant layer is formed on the outer peripheral surface of a stainless steel tubular shaft under predetermined heat treatment conditions. Is the same as 2 (A) to 2 (C) and FIGS. 3 (A) to 3 (C), the tubular shafts of the catheters 15A to 15F are indicated by reference numerals 1A to 1F, and the solid lubricant layer is shown. Like in FIG. 1, reference numeral 5 is attached.
[0041]
In the catheter 15A of Modification 1 shown in FIG. 2A, one end in the longitudinal direction of the tubular shaft 1A is formed such that the end surface at the one end is a surface inclined from the longitudinal axis direction of the tubular shaft 1A. , A low rigidity area 2A is formed.
[0042]
In the catheter 15B of Modification 2 shown in FIG. 2B, the shape of the tubular shaft 1B is the same as the shape of the tubular shaft 1 in the catheter 10 of the first embodiment, but at one end in the longitudinal direction of the tubular shaft 1B. The low-rigidity region 2B is formed by joining the coil springs 12 by welding, soldering, brazing, or the like.
[0043]
The coil spring 12 is made of the same or different metal as the material of the tubular shaft 1B. The outer diameter of the coil spring 12 is preferably substantially the same as the outer diameter of the solid lubricant layer 5, and the inner diameter thereof is preferably substantially the same as the inner diameter of the tubular shaft 1B. The element wire of the coil spring 12 preferably has a cross-sectional shape of, for example, a circle or a square. From the viewpoint of easy control of bending rigidity, the cross-sectional shape is desirably a square shape rather than a circular shape. The winding pitch of the coil spring 12 may be equal, or may increase or decrease gradually toward the distal end.
[0044]
In the catheter 15C of Modification 3 shown in FIG. 2C, a plurality of slits 13 (4 in the illustrated example) extending along the longitudinal axis of the tubular shaft 1C are provided at one longitudinal end of the tubular shaft 1C. However, in FIG. 2C, the two slits 13 appear in an overlapping state.), Thereby forming the low rigidity region 2C. The slits 13 are preferably formed at substantially equal intervals in the circumferential direction of the tubular shaft 1C.
[0045]
In the catheter 15D of Modification 4 shown in FIG. 3A, the low-rigidity region 2D is formed by gradually decreasing the thickness of one end of the tubular shaft 1D in the longitudinal direction toward the one end.
[0046]
In the fifth modification catheter 15E shown in FIG. 3B, the low-rigidity region 2E is formed by gradually decreasing the thickness of one end of the tubular shaft 1E in the longitudinal direction toward the one end. . In the illustrated example, the wall thickness of the tubular shaft 1E is reduced in three steps in the low-rigidity area 2E, and each step has a cylindrical shape.
[0047]
In the catheter 15F of Modification 6 shown in FIG. 3C, the low-rigidity region 2F is formed by spirally and stepwise decreasing the thickness of one end in the longitudinal direction of the tubular shaft 1F toward the one end. Is formed. In the illustrated example, the wall thickness of the tubular shaft 1F is divided into two or three steps in the low-rigidity area 2F and is reduced stepwise.
[0048]
Each of the catheters 15A to 15F of Modifications 1 to 6 described above has the fluororesin-based solid lubricant layer 5 on the outer peripheral surface of the tubular shafts 1A to 1F, similarly to the catheter 10 of the first embodiment. The same technical effects as those of the catheter 10 of the first embodiment can be obtained. Furthermore, since these catheters 15A to 15F have any of the above-described low rigidity regions 2A to 2F, the catheters 15A to 15F are used as hypotubes, for example, distal catheters such as vascular dilatation balloon catheters. If a long catheter is desired, which is desired to have relatively high flexibility at the end (low rigidity) and relatively low flexibility (high rigidity) at the proximal end, The technical effect of is obtained.
[0049]
That is, in obtaining the above-mentioned long catheter, even when a shaft having a relatively lower rigidity than the catheters 15A to 15F, such as a synthetic resin distal shaft, is joined to one end of each of the catheters 15A to 15F, By joining the low rigidity regions 2A to 2F so as to be included in the shaft, it is easy to suppress a sudden change in bending rigidity at the boundary between the hypotube and the distal shaft. As a result, it is possible to obtain a technical effect that it is easy to suppress crushing and kink of the distal shaft when the long catheter is inserted into a patient's body.
[0050]
The bending stiffness of the low rigidity areas 2A to 2F can be appropriately selected according to the use of the catheters 15A to 15F, and the length of each of the low rigidity areas 2A to 2F (the length along the longitudinal axis of the tubular shafts 1A to 1F). The thickness (the thickness of the element wire of the coil spring 12A in the low-rigidity area 2B shown in FIG. 2B) and the bending rigidity required for the low-rigidity areas 2A to 2F and the distance shaft The length can be appropriately selected according to the length of the joint at the time of connection (the length along the longitudinal axis of the tubular shafts 1A to 1F) and the like.
[0051]
For example, in the low-rigidity area 2A shown in FIG. 2A, the angle α (inner angle) formed by a plane including the end face of the tubular shaft 1A on the low-rigidity area 2A side and the longitudinal axis of the tubular shaft 1A is: It is preferable that the tangent tan α be selected to be approximately in the range of 0.003 to 0.015, and it is more preferable that the tangent tan α be selected to be approximately in the range of 0.005 to 0.01. The length of the low rigidity region 2A is naturally determined according to the outer diameter of the tubular shaft 1A and the tangent tanα.
[0052]
The outer ends of the low-rigidity regions 2A to 2F (ends in the longitudinal direction of the tubular shafts 1A to 1F) may be slightly rounded as necessary. This rounding makes it easy to prevent the inner surface of the distal shaft from being damaged by the outer ends of the low-rigidity regions 2A to 2F even when, for example, a distal shaft is connected to the outer end.
[0053]
<Second embodiment according to the catheter of the present invention>
FIGS. 4A and 4B schematically show a second embodiment of the catheter of the present invention. FIG. 4A schematically shows a state in which the catheter of the present embodiment is straightened, and FIG. 4B schematically shows a partial cross section of the catheter shown in FIG. 4A. The catheter 70 shown in these figures uses a catheter 15A shown in FIG. 2A as a hypotube (hereinafter, referred to as “hypotube 15A”) as a vascular dilatation balloon catheter (hereinafter, “vascular dilation balloon”). Catheter 70 "). In FIG. 4B, for convenience, the tubular shaft of the hypotube 15A and the fluororesin-based solid lubricant layer are depicted as one member without distinction.
[0054]
In the illustrated vascular dilatation balloon catheter 70, the connector 20 is connected to one end of the hypotube 15A (the end on the side where the low bending rigidity area 2A is not formed), and the other end (the side where the low bending rigidity area 2A is formed). A distal shaft 30 made of a synthetic resin is connected to each end, and a balloon 40 is connected to a distal end of an outer tube 32 constituting the distal shaft 30.
[0055]
The length of the hypotube 15A can be appropriately selected according to the use of the vascular dilatation balloon catheter 70, and is selected, for example, within a range of approximately 500 to 2000 mm, and more preferably within a range of approximately 700 to 1500 mm.
[0056]
The distal shaft 30 is a tubular member having a double structure (a so-called coaxial catheter tube structure) in which the inner tube 35 is disposed inside the outer tube 32. The proximal end of the outer tube 32 constituting the distal shaft 30 is airtightly joined to the distal end of the hypotube 15A by a method such as bonding, and the proximal end of the balloon 40 is connected to the distal end of the outer tube 32. The position ends are hermetically joined by a method such as heat fusion or adhesion.
[0057]
The length of the outer tube 32 can be appropriately selected according to the use of the vascular dilatation balloon catheter 70, and is selected in a range of approximately 100 to 400 mm, preferably in a range of approximately 200 to 300 mm. Further, the outer diameter of the outer tube 32 is preferably selected within a range of about 0.5 to 5.0 mm, more preferably within a range of 0.5 to 1.0 mm. The thickness of the outer tube 32 can also be appropriately selected, but is preferably selected within a range of approximately 0.05 to 0.5 mm, and more preferably selected within a range of approximately 0.1 to 0.2 mm. .
[0058]
Such an outer tube 32 is preferably formed of a synthetic resin having flexibility, and specific examples thereof include, for example, polyethylene, polyethylene terephthalate, polypropylene, ethylene-propylene copolymer, and ethylene-vinyl acetate copolymer. Examples include a polymer, polyvinyl chloride, a crosslinked ethylene-vinyl acetate copolymer, polyurethane, polyamide, polyamide elastomer, polyimide, and polyimide elastomer. Among these, it is particularly preferable to use those having a Shore A hardness of about 50 to 90, such as polyurethane, polyethylene, polyamide, and polyimide. Here, the “Shore A hardness” means a physical property value measured based on the provisions of JIS K-7215.
[0059]
On the other hand, the inner tube 35 constituting the distal shaft 30 extends from the outer peripheral surface of the outer tube 32 on the proximal end side to the outside of the balloon 40 via the inside of the outer tube 32 and the inside of the balloon 40, The proximal end is hermetically joined to the outer tube 32 by a method such as heat fusion or bonding, and is open to the outer peripheral surface of the outer tube 32. A distal end of the balloon 40 is air-tightly joined to the vicinity of the distal end of the inner tube 35 by a method such as heat fusion or adhesion, and the distal end of the inner tube 35 is a balloon catheter for vasodilation. 70 at the distal end. A guide wire 50 used when inserting the vascular dilatation balloon catheter 70 into a blood vessel is passed through the inner tube 35.
[0060]
The inner tube 35 can be formed of the same material as the outer tube 32, but can also be formed of a synthetic resin harder than the outer tube 32. The outer diameter of the inner tube 35 is preferably selected, for example, within a range of about 0.3 to 3.0 mm so that a gap is formed between the inner tube 35 and the inner peripheral surface of the outer tube 32. More preferably, it is selected within the range of 3 to 0.8 mm. The inner diameter of the inner tube 35 may be any size as long as the guide wire 50 can be inserted into the inner tube 35. For example, the inner diameter is within a range of about 0.1 to 1.0 mm, preferably about 0.25 to 0.6 mm. It can be selected within the range. The distance between the proximal end of the inner tube 35 and the distal end of the outer tube 32 (meaning the distance along the longitudinal axis of the distal shaft 30) is approximately 50 depending on the length of the outer tube 32. It is preferably within a range of from about 380 mm to 380 mm, and more preferably within a range of from about 150 to 280 mm.
[0061]
The balloon 40 is larger than the outer tube 32 and the inner tube 35 so that the balloon 40 can be inflated by introducing a fluid (gas or liquid) into the inside and can be deflated by discharging the introduced fluid. It is flexible. The balloon 40 before being inflated is folded and wound around the inner tube 35, and the outer diameter of the balloon 40 in this state is preferably approximately 0.5 to 3.5 mm. On the other hand, when the balloon 40 is inflated, the profile of the cross section at the center (the profile of the cross section in the direction orthogonal to the longitudinal axis direction) is circular or polygonal. The outer diameter of the balloon 40 in this state is preferably selected within a range of approximately 1.0 to 10.0 mm, depending on the use of the vascular dilatation balloon catheter 70, and is preferably approximately 1.5 to 5.0 mm. It is more preferable to select within the range. FIGS. 4A and 4B show a state where the balloon 40 is inflated (however, illustration of the fluid is omitted). The length of the balloon 40 in the longitudinal axis direction is determined by factors such as the size of the intravascular stenosis, but is generally in the range of 5 to 50 mm, preferably in the range of approximately 8 to 30 mm. It can be selected as appropriate.
[0062]
Such a balloon 40 is made of, for example, a copolymer of ethylene and another α-olefin such as polyethylene, polyethylene terephthalate, polypropylene, and ethylene-propylene copolymer, an ethylene-vinyl acetate copolymer, polyvinyl chloride, and a crosslinked type. Ethylene-vinyl acetate copolymer, polyurethane, polyamide, polyamide elastomer, polyimide, polyimide elastomer, silicone rubber, natural rubber, etc., the film thickness, so that desired flexibility and strength can be obtained, It is appropriately selected within a range of about 2 to 300 μm, preferably, within a range of about 2 to 50 μm. As a material of the balloon 40, polyethylene, polyethylene terephthalate, polyamide, or polyamide elastomer is preferable.
[0063]
The inner space of the hypotube 15A, the inner space of the outer tube 32 (excluding the inner tube 35), and the inner space of the balloon 40 are connected to each other to form one space. The supply of the fluid to the balloon 40 and the discharge of the fluid from the balloon 40 can be performed.
[0064]
If necessary, a contrast ring 60 made of a metal material such as gold, platinum, or tungsten can be attached to the outer peripheral surface of the inner tube 35 in the balloon 40. By attaching the contrast ring 60, when inserting the vascular dilatation balloon catheter 70 into the patient's body, the position of the balloon 40 in the patient's body can be accurately grasped by X-ray photography or the like. .
[0065]
In using the vascular dilatation balloon catheter 70 having the above-described configuration, first, the guide wire 50 is inserted into a patient's blood vessel, and then one end of the guide wire 50 is inserted from the distal end of the inner tube 35 to the inner tube 35. Passed through. Insertion of the vascular dilatation balloon catheter 70 into the blood vessel is performed by pushing the vasodilation balloon catheter 70 into the blood vessel from the balloon 40 side along the guide wire 50 until the balloon 40 reaches the stenosis portion of the blood vessel. Is
[0066]
In the vascular dilatation balloon catheter 70, since the catheter 15A of the above-described first modification is used as the hypotube, the pushing force of the operator is sufficiently transmitted to the distal end of the hypotube 15A, and the distal shaft 30 is used. The occurrence of crushing and kink is suppressed. Therefore, it is easy to insert the balloon 40 into the stenosis. In addition, since the outer peripheral surface of the hypotube 15A is formed by the fluororesin-based solid lubricant layer 5, it is easy to insert the balloon 40 to the stenotic portion of the blood vessel, and friction with the outer peripheral surface of the hypotube 15A is achieved. The blood vessel wall is also prevented from being damaged.
[0067]
After the balloon 40 reaches the stenosis of the blood vessel, gas or liquid is injected into the balloon 40 from the proximal end side of the hypotube 15A to inflate the balloon 40, thereby expanding the stenosis.
[0068]
At this time, since the hypotube 15A does not easily generate rust in the tubular shaft 1A as described above, even if the balloon 40 ruptures, the rust in the tubular shaft 1A may flow into the blood vessel. Less likely. Therefore, the safety of the vascular dilatation balloon catheter 70 using the hypotube 15A can be easily maintained for a long time.
[0069]
The vascular dilatation balloon catheter 70 and the guide wire 50 are sequentially removed from the blood vessel after the stenosis is inflated by the balloon 40. In the blood vessel after the stenosis is expanded by the balloon 40, the blood flow is restored.
[0070]
The outer periphery of the distal shaft 30 is preferably coated with a lubricating hydrophilic polymer substance from the viewpoint of reducing friction when the vascular dilatation balloon catheter 70 is inserted into a blood vessel. Although it is possible to coat the outer periphery of the balloon 40 with the hydrophilic polymer substance, it is not always preferable that the balloon 40 slide on the stenotic portion when the stenotic portion of the blood vessel is expanded.
[0071]
The hydrophilic polymer substance includes a natural polymer-based substance and a synthetic polymer-based substance. Examples of natural polymers include starch, cellulose, tannin / lignin, polysaccharide, and protein. Synthetic polymers include PVA, polyethylene oxide, acrylic acid, maleic anhydride, phthalic acid, water-soluble polyester, ketone aldehyde resin, (meth) acrylamide, polyamine, and water-soluble nylon. Etc. are exemplified.
[0072]
Among these, cellulose-based polymer substances (for example, hydroxypropyl cellulose), polyethylene oxide-based polymer substances (for example, polyethylene glycol), and maleic anhydride-based polymer substances (for example, maleic anhydride such as methyl vinyl ether-maleic anhydride copolymer) Acid copolymers) and acrylamide-based polymer substances (for example, polydimethylacrylamide) are particularly preferable as the above-mentioned hydrophilic polymer substances because a film having a low friction coefficient can be stably obtained.
[0073]
Although the present embodiment described above relates to a balloon catheter for vasodilation, the catheter 10 of the first embodiment described above, the catheters 15A to 15F of Modifications 1 to 6, and the catheters 18A to 18 of Modifications 7 to 12 described later. 18F can be widely used as a hypotube for long catheters that require relatively high flexibility at the distal end and relatively low flexibility at the proximal end.
[0074]
<Variations 7 to 12 according to the catheter of the present invention>
FIGS. 5 (A) to 5 (C) and FIGS. 6 (A) to 6 (C) separately show another modified example of the catheter of the present invention, particularly one component of a long catheter. 1 schematically illustrates a catheter suitable for (hypotube).
[0075]
In the catheters 18A to 18F of Modifications 7 to 12 shown in these figures, (1) the fluororesin-based solid lubricant layer is terminated before reaching from one end to the other end of the tubular shafts 1A to 1F to form a low-rigidity region. 2A to 2F are not covered with the fluororesin-based solid lubricant layer, and (2) the periphery of the low-rigidity regions 2A to 2F closes the openings on the low-rigidity regions 2A to 2F side of the tubular shafts 1A to 1F. The catheters are different from the catheters 15A to 15F of Modifications 1 to 6 in that they are covered with reinforcing tubes 17A to 17F so as not to be blocked. However, other configurations of the catheters 18A to 18F are the same as those of any of the catheters 15A to 15F of Modifications 1 to 6.
[0076]
For this reason, in FIGS. 5 (A) to 5 (C) and FIGS. 6 (A) to 6 (C), the tubular shafts and the low rigidity regions in the catheters 18A to 18F of Modifications 7 to 12 are respectively The same reference numerals as those used in the corresponding modified examples 1 to 6 are assigned. The fluororesin-based solid lubricant layers are sequentially denoted by reference numerals 5A to 5F, and the reinforcing tubes are sequentially denoted by reference numerals 17A to 17F.
[0077]
The reinforcing tubes 17A to 17F shown in these figures mechanically protect the low-rigidity areas 2A to 2F to prevent the low-rigidity areas 2A to 2F from being damaged, and construct a long catheter using the catheters 18A to 18F as hypotubes. Furthermore, it is for preventing the inner surface of the distal shaft from being damaged by the distal ends of the low rigidity regions 2A to 2F. For this reason, the tensile strength is preferably at least 27 MPa, more preferably at least 90 MPa. The bending strength is preferably at least 34 MPa, more preferably at least 130 MPa.
[0078]
Such reinforcing tubes 17A to 17F are formed of, for example, polyetheretherketone resin, and cover predetermined regions on the outer peripheral surfaces of the tubular shafts 1A to 1F. The inner diameter of the reinforcing tubes 17A to 17F is appropriately determined according to the outer diameter of the tubular shafts 1A to 1F (low rigidity regions 2A to 2F) so as to cover a predetermined region on the outer peripheral surface of the tubular shafts 1A to 1F. Selected. The thickness of the reinforcing tubes 17A to 17F is preferably selected within a range of approximately 10 to 200 μm, and more preferably within a range of approximately 30 to 100 μm.
[0079]
It is preferable that the coverage of the low-rigidity regions 2A to 2F by the reinforcing tubes 17A to 17F be as high as possible as long as the openings on the low-rigidity regions 2A to 2F side of the tubular shafts 1A to 1F are not closed.
[0080]
The catheters 18A to 18F of the modified examples 7 to 12 having the reinforcing tubes 17A to 17F have the same technical effects as the catheters 15A to 15F of the modified examples 1 to 6 described above. Furthermore, when these catheters 18A to 18F are used as hypotubes to form a long catheter having a distal shaft connected to the low-rigidity regions 2A to 2F, the long catheter is inserted into the body cavity of the patient. And the low rigidity regions 2A to 2F are prevented from being damaged when inserted into a blood vessel. As a result, the reliability of the long catheter can be improved.
[0081]
Note that the above-described reinforcing tubes 17A to 17F may be heat-shrinkable tubes that shrink by heating. When a heat-shrinkable tube is used as the reinforcing tubes 17A to 17F, it becomes easy to cover the low bending rigid regions 2A to 2F with the reinforcing tubes 17A to 17F.
[0082]
In the catheters 18A to 18F of Modifications 7 to 12, the tubular shafts 1A to 1F are locally located between the proximal ends of the reinforcing tubes 17A to 17F and the distal ends of the fluororesin-based solid lubricant layers 5A to 5F. The tubular shafts 1A to 1F are not necessarily exposed. The proximal ends of the reinforcing tubes 17A to 17F and the distal ends of the solid lubricant layers 5A to 5F may be in contact with each other. Further, similarly to the catheters 15A to 15F of the above-described modified examples 1 to 6, a fluororesin-based solid lubricant layer is formed on the entire outer peripheral surface of the tubular shafts 1A to 1F, and the outer peripheral surface of the solid lubricant layer is formed. The predetermined area may be covered with the reinforcing tubes 17A to 17F.
[0083]
<Embodiment of the manufacturing method of the catheter of the present invention>
Hereinafter, an embodiment according to a method for manufacturing a catheter of the present invention will be described by taking the catheter 10 of the first embodiment described above as an example. The following description will be made while appropriately referring to the reference numerals used in FIG.
[0084]
In the method for manufacturing a catheter of the present invention, first, a first step of preparing a tubular shaft 1 made of stainless steel is performed. The tubular shaft 1 can be manufactured in a manufacturing facility for the catheter 10, can be manufactured in a different facility from the manufacturing facility for the catheter 10, or a commercially available product can be purchased. The material and manufacturing method of the tubular shaft 1 have already been described in the description of the first embodiment relating to the catheter, and thus are omitted here.
[0085]
Next, a second step of coating the outer peripheral surface of the tubular shaft 1 with a material capable of forming the fluororesin-based solid lubricant layer 5 is performed. This material has already been described in the description of the first embodiment according to the catheter of the present invention, and thus is omitted here.
[0086]
The coating of the above-mentioned material can be performed by a method such as spray coating, electrostatic coating, fluid immersion coating, or the like, depending on the type of the material. Above all, it is particularly preferable to perform the coating by electrostatic coating. In order to increase the bonding strength between the tubular shaft 1 and the solid lubricant layer 5, it is preferable that the tubular shaft 1 be subjected to a pretreatment such as degreasing, sandblasting, etching, and primer application before the second step. .
[0087]
Next, a third step of heat-treating the material coated in the second step at 340 ° C. or lower to form a solid lubricant layer 5 on the outer peripheral surface of the tubular shaft 1 is performed. The heat treatment temperature may be 340 ° C. or less, but is preferably about 300 ° C. or less. If the heat treatment temperature is too low, the solid lubricant layer 5 having desired friction characteristics cannot be formed, or the joining strength between the solid lubricant layer 5 and the tubular shaft 1 becomes too low. The lower limit of the heat treatment temperature is preferably approximately 200 ° C., and more preferably approximately 260 ° C., depending on the type of material used in the second step. The heat treatment time is appropriately selected according to the type of the coating material used in the second step and the heat treatment temperature in the third step.
[0088]
In addition, from the viewpoint of obtaining the solid lubricant layer 5 having a uniform film thickness (thickness), the second step and the third step are preferably set as one set, and the set is preferably repeated twice or more as necessary. . When the set is repeated two or more times, the heat treatment temperature in the third step other than the final set can be set lower than the heat treatment temperature in the final set.
[0089]
By sequentially performing the above-described first to third steps, the catheter 10 of the above-described first embodiment can be obtained.
When a long catheter is obtained by using the catheter 10 as a hypotube, a fourth step of connecting a distal shaft to one end of the hypotube is performed following the third step, and then a balloon catheter is obtained. If so, a fifth step of connecting the balloon to the distal end of the distal shaft is performed. The method of joining the distal shaft and the hypotube and the method of joining the distal shaft and the balloon have already been described in the description of the second embodiment of the catheter according to the present invention, and thus will not be described here.
[0090]
【Example】
<Example 1>
A SUS304 tube having an inner diameter of 0.45 mm, an outer diameter of 0.65 mm, and a length of 1200 mm was prepared as a stainless steel tubular shaft (first step). As a material for the fluororesin-based solid lubricant layer, an organic solvent based on 15% by weight of FEP, 15% by weight of PTFE, and 20% by weight of an epoxy resin as a binder resin are dissolved in methyl isobutyl ketone. A modified fluorine paint was prepared.
[0091]
First, the tubular shaft was degreased with isopropyl alcohol (IPA), and the IPA used for degreasing was wiped off with a rag. Then, the tubular shaft was washed with water while the tubular shaft was set up.
[0092]
Next, the above-mentioned material was coated by electrostatic painting using an electrostatic painting gun with the tubular shaft standing (second step).
Next, the coated tubular shaft was preliminarily dried at 180 ° C. for 10 minutes in a hot air circulating electric furnace (third step).
[0093]
Thereafter, the water washing, the second step, and the preliminary drying (third step) are sequentially repeated in this order, and thereafter, heat treatment is performed by using a hot air circulating electric furnace at 210 ° C. for 40 minutes (final second step). 3) to obtain a catheter having the same shape as the catheter 10 shown in FIG.
[0094]
<Example 2>
A catheter was obtained in the same manner as in Example 1, except that the heat treatment (final third step) was performed at 220 ° C. for 40 minutes.
[0095]
<Example 3>
A catheter was obtained in the same manner as in Example 1, except that the heat treatment (final third step) was performed at 260 ° C. for 40 minutes.
[0096]
<Example 4>
A catheter was obtained in the same manner as in Example 1 except that the heat treatment (final third step) was performed at 300 ° C. for 40 minutes.
[0097]
<Comparative example>
As a material for the fluororesin-based solid lubricant layer, an aqueous dispersion paint in which 50% by weight of PTFE is dispersed in water is used, and heat treatment is performed at a temperature of 380 ° C. which is out of the range of the present invention (final third step). A catheter was obtained in the same manner as in Example 1 except that the procedure was performed.
[0098]
<Reference Examples 1 to 4>
Four tubular shafts having the same shape, size and material as the tubular shaft used in Example 1 were prepared, (1) the material of the solid lubricant layer was not applied to the tubular shaft, and (2) the final The heat treatment temperature in the third step was 250 ° C. in Reference Example 1, 300 ° C. in Reference Example 2, 345 ° C. in Reference Example 3, and 380 ° C. in Reference Example 4, except that the heat treatment was performed on each tubular shaft. The same processing as in Example 1 was performed.
[0099]
<Corrosion resistance test>
Each of the catheters obtained in Examples 1 to 4 and Comparative Example and each of the tubular shafts of Reference Examples 1 to 4 were cut in the longitudinal axis direction to obtain halved samples, respectively. It was immersed in water for 72 hours. Thereafter, the presence or absence of discoloration and the presence or absence of rust on the inner peripheral surface of each sample was visually confirmed, and the corrosion resistance was evaluated.
[0100]
Table 1 shows the evaluation results together with the heat treatment conditions in the final third step. 7 to 10 show the states of the samples obtained from the catheters of Examples 1 to 4 before and after the corrosion test in this order, and FIG. 11 shows the states of the samples obtained from the catheters of the comparative example before and after the corrosion test. .
[0101]
[Table 1]

[0102]
As is clear from Table 1, and as is clear from the comparison between FIGS. 7 to 10 and FIG. 11, by setting the heat treatment temperature at the time of forming the fluororesin-based solid lubricant layer to 340 ° C. or less. In addition, it is possible to suppress a decrease in the corrosion resistance of the stainless steel tubular shaft, and as a result, it is possible to suppress the generation of rust on the inner peripheral surface of the catheter (the tubular shaft).
[0103]
【The invention's effect】
As described above, according to the present invention, even when a fluororesin-based solid lubricant layer is formed on the outer peripheral surface of a stainless steel tubular shaft, rust is suppressed from being generated in the tubular shaft. It is possible to provide a catheter that can be easily inserted into a blood vessel or a blood vessel and that can easily maintain high safety for a long time.
[Brief description of the drawings]
FIG. 1A is a schematic view showing a state in which a catheter according to a first embodiment is straightened, and FIG. 1B is a longitudinal view of the catheter shown in FIG. 1A. FIG. 1C is a schematic view of a cross section when cut along a plane including an axis, and FIG. 1C is a schematic cross section when the catheter shown in FIG. 1A is cut along a plane with its longitudinal axis as a normal line. FIG.
FIGS. 2 (A) to 2 (C) are schematic views each showing a modified example of the catheter of the present invention, partially cut away.
FIGS. 3 (A) to 3 (C) are schematic views each showing another modified example of the catheter of the present invention, partially cut away.
FIG. 4 (A) is a schematic view showing a state where the catheter of the second embodiment is straightened, and FIG. 4 (B) is a cross-sectional view of the catheter shown in FIG. 4 (A). It is the schematic which partially shows.
5 (A) to 5 (C) are schematic views each showing another modified example of the catheter of the present invention separately.
FIGS. 6 (A) to 6 (C) are schematic views each showing another modified example of the catheter of the present invention separately.
FIG. 7 is a photograph as a drawing showing conditions of a sample obtained from the catheter of Example 1 before and after a corrosion resistance test.
FIG. 8 is a photograph as a drawing showing conditions before and after a corrosion test of a sample obtained from the catheter of Example 2.
FIG. 9 is a photograph as a substitute of a drawing showing a state of a sample obtained from the catheter of Example 3 before and after a corrosion resistance test.
FIG. 10 is a photograph as a drawing showing conditions before and after a corrosion resistance test of a sample obtained from the catheter of Example 4.
FIG. 11 is a photograph as a substitute of a drawing showing a state before and after a corrosion resistance test of a sample obtained from a catheter of a comparative example.
[Explanation of symbols]
1, 1A-1F Tubular shaft made of stainless steel
5,5A-5F Fluororesin-based solid lubricant layer
10, 15A-15F, 18A-18F Catheter (hypotube)
30 Distal shaft
40 balloon
70 Balloon catheter for vasodilation

Claims (10)

Having a stainless steel tubular shaft and a fluororesin-based solid lubricant layer formed on the outer peripheral surface of the tubular shaft,
A catheter in which the solid lubricant layer is formed by coating the material of the solid lubricant layer on the outer peripheral surface and then heat-treating the material at 340 ° C. or lower. The catheter according to claim 1, wherein the tubular shaft is made of austenitic stainless steel. The catheter according to claim 1, wherein the material includes a binder resin having a relatively low melting point and a fluorine-based resin having a relatively high melting point. The catheter according to any one of claims 1 to 3, wherein the material is heat-treated at 200 to 340 ° C. The catheter according to any one of claims 1 to 4, wherein one end of the flexible shaft is connected to one end of the tubular shaft, and a balloon is connected to the other end of the distal shaft. . A first step of preparing a stainless steel tubular shaft;
A second step of coating a material capable of forming a fluororesin-based solid lubricant layer on the outer peripheral surface of the tubular shaft;
A third step of heat-treating the material at 340 ° C. or lower to form the fluororesin-based solid lubricant layer on the outer peripheral surface of the tubular shaft;
A method for producing a catheter comprising: The method according to claim 6, wherein the tubular shaft prepared in the first step is made of austenitic stainless steel. The method according to claim 6, wherein the material used in the second step includes a binder resin having a relatively low melting point and a fluorine-based resin having a relatively high melting point. The method according to claim 6, wherein the material is heat-treated at 200 to 340 ° C. in the third step. Further, a fourth step of connecting one end of a flexible distal shaft to one end of the tubular shaft after the third step,
A fifth step of connecting a balloon to the other end of the distal shaft,
The method for producing a catheter according to any one of claims 6 to 9, comprising:

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