JP4852814B2 - Stent delivery catheter - Google Patents

Description

本発明に係る実施例１から４ではステントの移動或いは脱落が殆ど発生せず、体内への挿入特性も良好だった。比較例１ではステントの移動或いは脱落が発生しやすく、ステントデリバリーカテーテルとしては不適当であることが明らかになった。また、比較例２ではステントの移動或いは脱落は発生しないものの、バルーンの先端側テーパー部及び後端側テーパー部の折り畳み外径が大きすぎるためガイドカテーテル内で大きな抵抗を生じ、操作性が極めて悪いことが示された。
【００４１】
【発明の効果】
以上の如く、本発明のステントデリバリーカテーテルによれば、前記ステントデリバリーカテーテルは先端部と後端部を有し、前記後端部には圧力流体供給用のポートを有するハブを有し、前記先端部には円筒形状の直管部及び前記直管部の先端側及び後端側に円錐台形状のテーパー部を備えた折り畳み可能なバルーンを有し、前記先端側テーパー部略中央部の肉厚Ｔ１と前記直管部略中央部の肉厚Ｔ２の間に１．３≦（Ｔ１／Ｔ２）≦２．５なる関係が成立すると同時に、前記後端側テーパー部略中央部の肉厚Ｔ３と前記直管部略中央部の肉厚Ｔ２の間に１．３≦（Ｔ３／Ｔ２）≦２．５なる関係が成立し、折り畳まれた前記バルーンの直管部の外面に前記ステントが収縮状態で配設されており、折り畳まれた前記バルーンの先端側テーパー部及び前記バルーンの後端側テーパー部により前記ステントのカテーテル軸方向への移動が抑制されることを特徴とするため、狭窄部まで挿入する際にステントの脱落や移動が発生しないステントデリバリーカテーテルを提供することが可能である。また、移動防止のための特別な部材を必要としないので、部品点数の増加や加工工数の増加による製造工程の煩雑化を伴わずに効率良く製造することが可能である。
【図面の簡単な説明】
【図１】一般的なバルーンカテーテルのうち、高速交換型の概略斜視図である。
【図２】一般的なバルーンカテーテルのうち、オーバー・ザ・ワイヤー型の概略斜視図である。
【図３】一般的なバルーンカテーテルのコアキシャル構造の断面を示す概略側面図である。
【図４】図３のＡ−Ａ’断面図である。
【図５】一般的なバルーンカテーテルのバイアキシャル構造の断面を示す概略側面図である。
【図６】図５のＢ−Ｂ’断面図である。
【図７】先端側テーパー部略中央部の肉厚Ｔ１と直管部略中央部の肉厚Ｔ２の間に（Ｔ１＜Ｔ２）＜１．３なる関係が成立すると同時に、後端側テーパー部略中央部の肉厚Ｔ３と前記直管部略中央部の肉厚Ｔ２の間に（Ｔ３／Ｔ２）＜１．３なる関係が成立するバルーンを備えたステントデリバリーカテーテルにおいて、バルーンを折り畳み、ステントを配設した場合の概略斜視図である。
【図８】先端側テーパー部略中央部の肉厚Ｔ１と直管部略中央部の肉厚Ｔ２の間に１．３≦（Ｔ１＜Ｔ２）なる関係が成立すると同時に、後端側テーパー部略中央部の肉厚Ｔ３と前記直管部略中央部の肉厚Ｔ２の間に１．３≦（Ｔ３／Ｔ２）なる関係が成立するバルーンを備えたステントデリバリーカテーテルにおいて、バルーンを折り畳み、ステントを配設した場合の概略斜視図である。
【図９】体内への挿入特性を評価する評価系の概略図である。
【符号の説明】
１ バルーン
１Ａ 直管部
１Ｂ 先端側テーパー部
１Ｃ 後端側テーパー部
２ アウターチューブ
３ インナーチューブ
４ Ｘ線不透過マーカー
５ ガイドワイヤルーメン
６ インフレーションルーメン
７ デュアルルーメンチューブ
８ ハブ
９ ガイドワイヤ入口部
１０ ステント
１１ ガイドカテーテル
１２ ヘモスタックバルブ
１３ ガイドワイヤ
１４ ステントデリバリーカテーテル先端サンプル[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a delivery catheter for introduction and placement of a stent used for dilatation treatment of a stenosis formed in a blood vessel, esophagus, trachea, urethra, bile duct and the like, and in particular, introduction of a stent in a stenosis of a cardiac coronary artery And a delivery catheter for placement.
[0002]
[Prior art]
Stents are widely used as devices that are placed in stenosis portions formed in blood vessels, esophagus, trachea, urethra, bile ducts, and other stenosis to efficiently secure a lumen. The stent is introduced into the vessel in a folded state, placed in the desired stenosis, expanded to a predetermined size, and deployed.
[0003]
Stents are roughly classified into the following two types according to the mechanism when expanded to a predetermined size. One is a stent made of a shape memory alloy or the like, and is a self-expandable stent that can be expanded without mechanically expanding the stent. The other is a stent that requires expansion of a mechanical stent, and is generally a balloon expandable type that is expanded by a known balloon catheter used to expand vessels, particularly arteries and veins. A stent (balloon-expandable stent).
[0004]
The balloon-expandable stent does not have an expansion function in the stent itself, and in order to place the stent in the desired stenosis, the stent attached to the balloon part of the balloon catheter is placed to the desired stenosis, and then the balloon is expanded. In general, a method of bringing the stent into close contact with the inner surface of the stenosis by plastically deforming the stent by the expansion force of the balloon is generally performed.
[0005]
When a balloon-expandable stent is placed by the above method, it is necessary to insert a balloon catheter with the stent attached to the balloon part to the stenosis part. At the time of insertion, there is a risk that the stent moves on the balloon and falls off the balloon catheter. is there. A balloon generally used for a balloon catheter has a shape in which a truncated cone-shaped tapered portion is formed before and after a straight tube portion that expands into a cylindrical shape, and a balloon expandable stent is formed on the outer surface of the straight tube portion. Is installed. Even if the stent moves on the front and back of the straight tube portion even if the stent moves on the balloon and does not fall off the balloon catheter at the time of insertion, one end of the stent will be located on the outer surface of the tapered portion of the balloon. . Since the balloon in this portion is expanded only in a tapered shape, the stent is insufficiently expanded, and there is an extremely high possibility that restenosis of the stenosis portion will occur.
[0006]
From the above viewpoint, a prior art for preventing the stent from dropping or moving to a balloon catheter used for placement of a balloon expandable stent is disclosed.
[0007]
Japanese Patent Application Laid-Open No. 8-164210 discloses an intravascular support device having means for encapsulating a stent. In this prior art, encapsulation is realized by heating, pressurizing, and cooling the balloon so that the balloon expands around the folded stent.
[0008]
However, the process of heating, pressurizing, and cooling the balloon causes mechanical or thermal damage to the balloon, and there is a concern that the pressure strength may be lowered and pinholes may be generated. It is necessary to introduce a process, and there is a concern that the process is complicated.
[0009]
Japanese Patent Laid-Open No. 9-276414 discloses a technique for forming a layer having a large coefficient of friction on the outer surface of a balloon as a stent delivery system having a stent holding means for preventing the stent from moving from the balloon, and exists inside the balloon. A technique has been disclosed in which a portion (saddle or sheet) having a small diameter is provided in an inner tube, and a stent is disposed on the outer surface of a balloon on the sheet portion.
[0010]
Although both are effective as a stent holding means, a new process is required during the manufacturing process, and the process becomes complicated.
[0011]
Further, in Japanese Patent Application Laid-Open No. 11-128366, two collars are opposed to each other on the outer periphery of a portion located inside the balloon and are spaced apart in parallel, and a tubular adapter is disposed on the outer periphery of the portion between the two collars. A balloon structure is disclosed in which a balloon is wound around a collar and a tubular adapter, and a mechanism for preventing movement of the stent disposed around the balloon to both sides in the axial direction is formed.
[0012]
Also in this prior art, since it is necessary to join two collars and a tubular adapter to the outer periphery of the part located inside the balloon, it will be judged that the manufacturing process is complicated and the cost is increased.
[0013]
[Problems to be solved by the invention]
Therefore, in view of the above problems, the problem to be solved by the present invention is to insert a balloon catheter with a stent attached to a stenosis without complicating the manufacturing process due to an increase in the number of parts and an increase in processing steps. It is an object of the present invention to provide a stent delivery catheter that does not cause the stent to drop or move.
[0014]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, a stent delivery catheter for delivering a stent for treatment of a stenosis in a living body to the stenosis, wherein the stent delivery catheter has a front end and a rear end, and the rear A hub having a pressure fluid supply port is provided at the end, and the tip is provided with a cylindrical straight pipe part and a truncated cone-shaped tapered part on the front end side and rear end side of the straight pipe part. There is a foldable balloon, and a relationship of 1.3 ≦ (T1 / T2) ≦ 2.5 between the wall thickness T1 of the tip side taper portion substantially central portion and the wall thickness T2 of the straight pipe portion substantially center portion Is established, and a relationship of 1.3 ≦ (T3 / T2) ≦ 2.5 is established between the thickness T3 of the substantially central portion of the rear end side tapered portion and the thickness T2 of the substantially central portion of the straight pipe portion. Of the straight tube portion of the balloon folded while decompressing the inside. The stent contracted state on the surface is disposed in a state of being brought into close contact with the further balloon outer surface with heat shrinkable tube, the distal side tapered portion of the balloon which is folded while reducing the pressure inside and the rear end side of the balloon The stent delivery catheter is characterized in that the movement of the stent in the catheter axial direction is suppressed by the tapered portion.
[0015]
In this case, a relationship of 1.6 ≦ (T1 / T2) ≦ 2.5 is established between the thickness T1 of the tip side taper portion substantially central portion and the thickness T2 of the straight pipe portion substantially center portion, A relationship of 1.6 ≦ (T3 / T2) ≦ 2.5 is established between the thickness T3 of the substantially central portion of the rear end side tapered portion and the thickness T2 of the substantially central portion of the straight pipe portion. More preferable.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, various embodiments of a stent delivery catheter according to the present invention will be described in detail with reference to the drawings.
[0017]
The stent delivery catheter according to the present invention is a high-speed exchange type catheter having a guide wire lumen 5 only at the distal end side of the catheter as shown in FIG. 1, or a guide wire lumen over the entire length of the catheter as shown in FIG. Any structure of an over-the-wire catheter with 5 is possible.
[0018]
Further, the structure of the stent delivery catheter is not limited as long as the guide wire lumen 5 and the inflation lumen 6 are provided. That is, the outer tube 2 and the inner tube 3 are arranged in a coaxial double tube, and the inflation wire 6 determined by the guide wire lumen 5 and the inner surface of the outer tube 2 and the outer surface of the inner tube 3 inside the inner tube. A co-axial structure (FIGS. 3 and 4) having a bi-axial structure with a dual lumen tube 7 in which a guide wire lumen 5 and an inflation lumen 6 are arranged in parallel is also possible. The structure (FIGS. 5 and 6) may be used. Moreover, even if it is structures other than illustrated above, the effect of this invention is not restrict | limited at all.
[0019]
The balloon 1 according to the present invention has a cylindrical straight tube portion 1A, a truncated cone-shaped tapered portion 1B on the distal end side of the straight tube portion, and a truncated cone-shaped tapered portion 1C on the rear end side of the straight tube portion. However, the taper angle in the taper portions 1B and 1C is not limited, and an arbitrary angle can be selected.
[0020]
The balloon 1 can be folded, and can be folded long and narrow by winding the balloon 1 along the inner tube 3 while decompressing the inside of the balloon 1. By disposing the contracted stent 10 on the outer surface of the folded balloon 1, preferably on the outer surface of the straight tube portion 1A, the stent can be inserted into the body using a balloon catheter.
[0021]
A relationship of (T1 / T2) <1.3 is established between the thickness T1 of the substantially tapered portion at the front end side taper portion and the thickness T2 of the substantially central portion of the straight pipe portion, and at the same time, the tapered shape of the rear end side tapered portion. When a relationship of (T3 / T2) <1.3 is established between the thickness T3 of the central portion and the thickness T2 of the straight tube portion approximately the central portion, the balloon 10 is folded and the stent 10 in the contracted state is formed. When disposed, the outer diameter of the contracted stent 10 becomes larger than the outer diameters of the straight tube portion 1A, the front end taper portion 1B, and the rear end taper portion 1C of the balloon 1, and the stent 10 is inserted into the body. The stent 10 may move on the surface of the balloon 1 due to friction with the hemostack valve or the guide catheter that occurs when the stent 10 is moved. (FIG. 7) Here, the expression “substantially central” in the present invention means “substantially central” and is defined to mean a range of ± 1 mm from the true central portion.
[0022]
On the other hand, when the relationship of 1.3 ≦ (T1 / T2) is established at the same time as the relationship of 1.3 ≦ (T3 / T2) is established, the thicknesses of the front end side taper portion 1B and the rear end side taper portion 1C are increased. Due to the thickness, the folded front end side taper portion 1B and rear end side taper portion 1C portion become bulky so that it becomes larger than the outer diameter of the stent 10 in the contracted state, and the stent 10 on the surface of the balloon 1 It becomes possible to suppress movement and dropout from the catheter. (Fig. 8)
In the case of the stent 10 for treating coronary arteries, taking into consideration that the thickness of the metal elements constituting the stent is suitably about 100 μm to 150 μm, in order to prevent the stent 10 from moving and dropping more effectively. More preferably, the relationship of 1.6 ≦ (T1 / T2) is satisfied and the relationship of 1.6 ≦ (T3 / T2) is satisfied.
[0023]
However, when the relationship of 2.5 <(T1 / T2) is established and at the same time the relationship of 2.5 <(T3 / T2) is established, the thickness of the front end side taper portion 1B and the rear end side taper portion 1C is increased. As described above, the folded distal end taper portion 1B and rear end taper portion 1C are bulky due to the thickness. However, the outer diameter of the contracted stent 10 is excessively bulky. Becomes much larger than. In this case, when the stent delivery catheter is inserted into the stenosis portion in the bent blood vessel or along the guide catheter, the followability to the bending is extremely lowered and the operability is deteriorated. In addition, there is a high risk of damaging the inner wall of the blood vessel due to the excessive bulkiness of the folded front end side taper portion 1B or rear end side taper portion 1C. In addition, when the balloon catheter decompressed after expanding the stent 10 is removed from the body, there is a high risk that the balloon 1 will be caught inside the stent 10 and will be difficult to remove.
[0024]
As described above, the relationship of 1.3 ≦ (T1 / T2) ≦ 2.5 is established between the thickness T1 of the tip side taper portion substantially central portion and the thickness T2 of the straight pipe portion substantially center portion, Preferably, a relationship of 1.3 ≦ (T3 / T2) ≦ 2.5 is established between the thickness T3 of the substantially central portion of the rear end side tapered portion and the thickness T2 of the substantially central portion of the straight pipe portion, At the same time as the relationship of 1.6 ≦ (T1 / T2) ≦ 2.5 is established between the thickness T1 of the front end taper portion substantially central portion and the thickness T2 of the straight pipe portion substantially central portion, the rear end It is more preferable that a relationship of 1.6 ≦ (T3 / T2) ≦ 2.5 is established between the thickness T3 of the substantially central portion of the side taper portion and the thickness T2 of the substantially central portion of the straight pipe portion. .
[0025]
As a manufacturing method of the balloon 1, there are dipping molding, blow molding and the like, and it is possible to select a suitable method. However, in order to realize a sufficient pressure resistance required for the balloon for stent expansion, blow molding is used. preferable. For example, a tubular parison having an arbitrary size is first formed by extrusion molding or the like. A balloon having the same shape as the mold shape can be formed by disposing the tubular parison in a mold having a shape corresponding to the balloon shape and stretching it in the axial direction and the radial direction by a biaxial stretching process. .
It is obvious for those skilled in the art that T1 and T3 can be changed while T2 is kept substantially constant by adjusting the amount of stretching in the axial direction and the balance of biaxial stretching. In order to change only T1 and T3 more effectively, it is preferable to carry out the biaxial stretching step under heating conditions and to perform biaxial stretching a plurality of times, and the straight pipe portion 1A and the tip side taper portion 1B. It is more preferable to use an apparatus that can arbitrarily heat each of the rear end side tapered portions 1C and selectively / biaxially stretch any portion. Further, the axial stretching may be performed simultaneously with or before or after the radial stretching, and may be subjected to an annealing treatment in order to stabilize the shape and dimensions of the balloon. As described above, it is possible to suppress the movement of the stent 10 without complicating the manufacturing process by optimizing the biaxial stretching conditions.
[0026]
The material of the balloon 1 does not affect the effect of the present invention as long as it is a biaxially stretchable material, and polyolefin, polyolefin elastomer, polyester, polyester elastomer, polyamide, polyamide elastomer, polyurethane, polyurethane elastomer, etc. can be used. From the viewpoint of realizing a pressure strength that sufficiently expands the stent 10, polyester, polyester elastomer, polyamide, and polyamide elastomer are preferable.
[0027]
The material of the inner tube 3 does not affect the effect of the present invention and is not particularly limited. In the case of the coaxial structure shown in FIG. 3, polyolefin, polyolefin elastomer, polyester, polyester elastomer, polyamide, polyamide elastomer, polyurethane, polyurethane elastomer, or the like can be used as the inner tube 3. Since the lumen 5 is defined, in consideration of the sliding property of the guide wire, polyethylene, particularly high-density polyethylene is preferable. In addition, the inner tube 3 may have a multilayer structure, and the innermost layer may be made of a high-density polyethylene and the outermost layer may be made of a material that can be bonded or fused to the balloon 1 in order to ensure the slidability of the guide wire. Furthermore, in order to further improve the slidability of the guide wire, it is possible to apply a lubricious coating such as silicon or polytetrafluoroethylene on the inner surface of the inner tube 3. Even in the case of the biaxial structure and other cases, it is possible to select a suitable material in consideration of the above contents.
[0028]
The material of the outer tube 2 is not particularly limited as in the case of the inner tube 3, and polyolefin, polyolefin elastomer, polyester, polyester elastomer, polyamide, polyamide elastomer, polyurethane, polyurethane elastomer, or the like can be used.
[0029]
As the material constituting the hub 8, polycarbonate, polyamide, polyurethane, polysulfone, polyarylate, styrene-butadiene copolymer, polyolefin and the like can be suitably used.
[0030]
The method for joining the balloon 1 to the outer tube 2 and the inner tube 3 is not particularly limited, and a known technique, that is, adhesion using an adhesive, fusion, or the like can be used. Further, the composition and chemical structure of the adhesive used and the curing type are not limited. From the point of composition and chemical structure, adhesives such as urethane type, silicone type, epoxy type and cyanoacrylate type can be used. From the point of curing type, two-component mixed type, UV curable type, water absorption curable type Adhesives such as heat curing type and radiation curing type can be used. However, when an adhesive is used, the hardness after curing is such that the rigidity of the joint does not change discontinuously before and after the joint at the joint between the balloon 1 and the outer tube 2 and between the balloon 1 and the inner tube 3. It is preferable to use an adhesive having the following, and can be selected in consideration of the rigidity of the balloon 1, the outer tube 2, and the inner tube 3.
[0031]
The material of the radiopaque marker 4 may be any material that is radiopaque, and any type of material such as metal or resin may be used. Moreover, the fixing method of the radiopaque marker 4 is not limited.
[0032]
A hydrophilic coating can be applied to the outer surface of the stent delivery catheter to facilitate insertion. That is, it is preferable to apply a hydrophilic coating that exhibits lubricity when in contact with blood to a portion that comes into contact with blood. The kind of hydrophilic coating is not particularly limited, and hydrophilic polymers such as poly (2-hydroxyethyl methacrylate), polyacrylamide, and polyvinylpyrrolidone, or blends thereof can be suitably used, and the coating method is not particularly limited.
[0033]
In addition, a hydrophobic coating can be applied to the outer surface of the balloon 1 in order to prevent the balloon 1 from slipping during positioning and post-dilatation after stent expansion on the surface of the balloon 1. . The kind of the hydrophobic coating is not particularly limited, and a hydrophobic polymer such as silicon can be suitably used, and the coating method is not particularly limited.
[0034]
The stent 10 according to the present invention may be a balloon-expandable stent, and the material is not particularly limited, but stainless steel such as SUS316 can be preferably used. In addition, the design of the stent 10 is not limited at all.
[0035]
【Example】
Specific examples and comparative examples according to the present invention will be described in detail below, but it is obvious that the present invention is not limited to the following examples.
Example 1
A tubular parison (inner diameter: 0.51 mm, outer diameter: 1.02 mm) was produced by an extrusion method using a polyamide elastomer (trade name: PEBAX7033SA01; manufactured by elfatochem), and then biaxially stretched blow using this parison A balloon with an outer diameter of 3.00 mm in the straight tube portion, a wall thickness of about 26 μm at the front end taper portion, a wall thickness of about 19 μm at the straight tube portion, and a wall thickness of about 25 μm at the rear end taper portion. Was made. In addition, the thickness of the front end side taper portion substantially central portion, straight pipe portion substantially center portion, and rear end side taper portion substantially center portion is a laser focus displacement meter (controller: LT-8100, head: LT-8010, camera unit: LT. -V201, all manufactured by Keyence Corporation).
[0036]
The inner tube (inner diameter 0.42 mm, outer diameter 0.56 mm) and outer tube (inner diameter 0.71 mm, outer diameter 0.88 mm) were prepared by extrusion molding using a polyamide elastomer (trade name: PEBAX7233SA01; manufactured by elf atchem). did.
[0037]
The stent was prepared by cutting a SUS316L tube (inner diameter 1.80 mm, outer diameter 2.05 mm) into a desired pattern by laser processing and then electrolytic polishing.
[0038]
After the outer tube and the balloon were joined by heat welding, the outer peripheral surface of the outer tube at the rear end side of about 200 mm from the joined portion of the outer tube and the balloon was cut by about 180 ° in the circumferential direction to produce a cut portion. The inner tube was inserted from the notch and was arranged coaxially with the outer tube. At this time, one end of the inner tube is made to coincide with the cut portion, and the other end is positioned on the tip side from the balloon by penetrating the inside of the balloon, and then the outer tube and the inner tube are joined by heat welding at the cut portion, The balloon and the inner tube were joined by heat welding on the balloon tip side. In joining, a core material of an arbitrary size coated with a highly lubricious material such as molded polytetrafluoroethylene was appropriately used to secure an inflation lumen or a guide wire lumen.
[0039]
While decompressing the balloon, the balloon is folded into a triset shape (the number of folded wings is 3), the contracted stent is placed in the straight tube of the balloon, and the heat-shrinkable tube placed on the outer surface of the stent is contracted to contract. The stent was closely attached to the outer surface of the balloon. Finally, the sample from which the heat-shrinkable tube was removed was used as a tip portion sample of the high-speed exchange type stent delivery catheter.
(Example 2)
Changed biaxial stretch blow molding conditions, straight pipe part outer diameter 2.95mm, tip side taper part approximately center thickness 38μm, straight pipe part substantially center part thickness 21μm, rear end side taper part approximate center It was produced in the same manner as in Example 1 except that the thickness of the part was 40 μm.
(Example 3)
Changed biaxial stretch blow molding conditions, straight pipe part outer diameter 2.97mm, tip side taper part approximately center thickness 34μm, straight pipe part approximately center part thickness 20μm, rear end side taper part approximately center It was produced in the same manner as in Example 1 except that the thickness of the part was 33 μm.
Example 4
A tubular parison (inner diameter: 0.51 mm, outer diameter: 1.12 mm) was produced by an extrusion method using a polyamide elastomer (trade name: PEBAX7033SA01; manufactured by elfatochem), and then biaxially stretched blow using this parison Balloon having a straight tube portion outer diameter of 2.92 mm, a tip side taper portion substantially central portion thickness of 57 μm, a straight tube portion substantially center portion thickness of 23 μm, and a rear end side taper portion substantially center portion of a thickness of 53 μm. It was produced in the same manner as in Example 1 except that was produced.
(Comparative Example 1)
Changed the biaxial stretch blow molding conditions, straight pipe part outer diameter 3.02mm, tip side taper part approximately center thickness 24μm, straight pipe part substantially center part thickness 19μm, rear end side taper part approximately center This was prepared in the same manner as in Example 1 except that the thickness of the part was 23 μm.
(Comparative Example 2)
Changed the biaxial stretch blow molding conditions, straight pipe part outer diameter 2.91mm, tip side taper part approximate center thickness 62μm, straight pipe part approximate center part thickness 23μm, rear end side taper part approximate center This was prepared in the same manner as in Example 4 except that the thickness of the part was 60 μm.
(Evaluation of stent migration prevention characteristics)
The sample was moved back and forth while holding the stent portion of the produced sample, and it was qualitatively evaluated whether or not the stent could easily move or drop out.
(Evaluation of insertion characteristics into the body)
The operability of inserting the prepared sample into the body was evaluated. For the evaluation, as shown in FIG. 9, a guide catheter 11, hemostack valve 12, and guide wire 13 were arranged, and a system in which water was circulated inside the guide catheter 11 and hemostack valve 12 was used. A sample was inserted from the inlet of the hemostack valve 12 and the operability at the time of insertion was evaluated.
(Evaluation results)
[0040]
[Table 1]

In Examples 1 to 4 according to the present invention, the stent hardly moved or dropped out, and the insertion characteristics into the body were good. In Comparative Example 1, it was revealed that the stent was easily moved or dropped out, which was inappropriate as a stent delivery catheter. In Comparative Example 2, the stent does not move or drop off, but the folded outer diameters of the front end taper portion and the rear end taper portion of the balloon are too large, resulting in a large resistance in the guide catheter and extremely poor operability. It was shown that.
[0041]
【The invention's effect】
As described above, according to the stent delivery catheter of the present invention, the stent delivery catheter has a distal end portion and a rear end portion, and the rear end portion has a hub having a pressure fluid supply port. The tube has a cylindrical straight tube portion and a foldable balloon having a truncated cone-shaped taper portion on the front end side and the rear end side of the straight tube portion, and the wall thickness of the substantially central portion of the front end taper portion A relationship of 1.3 ≦ (T1 / T2) ≦ 2.5 is established between T1 and the thickness T2 of the straight tube portion substantially central portion, and at the same time, the thickness T3 of the rear end taper portion substantially central portion A relationship of 1.3 ≦ (T3 / T2) ≦ 2.5 is established between the thickness T2 of the substantially central portion of the straight tube portion, and the stent is contracted on the outer surface of the straight tube portion of the folded balloon. The tip side taper of the balloon is arranged and folded Since the movement of the stent in the catheter axial direction is suppressed by the tapered portion of the balloon and the rear end side of the balloon, a stent delivery catheter that does not cause the stent to drop or move when inserted to the stenosis is provided. It is possible to provide. In addition, since no special member for preventing movement is required, it is possible to manufacture efficiently without complicating the manufacturing process due to an increase in the number of parts and an increase in the number of processing steps.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of a high-speed exchange type among general balloon catheters.
FIG. 2 is a schematic perspective view of an over-the-wire type of a general balloon catheter.
FIG. 3 is a schematic side view showing a cross section of a coaxial structure of a general balloon catheter.
4 is a cross-sectional view taken along line AA ′ of FIG.
FIG. 5 is a schematic side view showing a cross section of a biaxial structure of a general balloon catheter.
6 is a cross-sectional view taken along the line BB ′ of FIG.
FIG. 7 shows that a relationship of (T1 <T2) <1.3 is established between the wall thickness T1 of the front end taper portion substantially central portion and the wall thickness T2 of the straight tube portion substantially central portion, and at the same time the rear end taper portion In a stent delivery catheter provided with a balloon in which a relationship of (T3 / T2) <1.3 is established between a thickness T3 at a substantially central portion and a thickness T2 at a substantially central portion of the straight pipe portion, the balloon is folded, and the stent It is a schematic perspective view at the time of arrange | positioning.
FIG. 8 shows that a relationship of 1.3 ≦ (T1 <T2) is established between the wall thickness T1 of the front end taper portion substantially central portion and the wall thickness T2 of the straight pipe portion substantially center portion, and at the same time, the rear end taper portion In a stent delivery catheter having a balloon in which a relationship of 1.3 ≦ (T3 / T2) is established between a thickness T3 at a substantially central portion and a thickness T2 at a substantially central portion of the straight pipe portion, the balloon is folded, and the stent It is a schematic perspective view at the time of arrange | positioning.
FIG. 9 is a schematic diagram of an evaluation system for evaluating insertion characteristics into the body.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Balloon 1A Straight pipe part 1B Tip side taper part 1C Rear end side taper part 2 Outer tube 3 Inner tube 4 X-ray opaque marker 5 Guide wire lumen 6 Inflation lumen 7 Dual lumen tube 8 Hub 9 Guide wire entrance part 10 Stent 11 Guide catheter 12 Hemostack valve 13 Guide wire 14 Stent delivery catheter tip sample

Claims (2)

A stent delivery catheter for delivering a stent for treatment of a stenosis in a living body to the stenosis, wherein the stent delivery catheter has a front end and a rear end, and a pressure fluid supply is provided at the rear end. And a foldable balloon having a cylindrical straight tube portion and a truncated cone-shaped tapered portion on the front end side and the rear end side of the straight tube portion at the front end portion, At the same time as the relationship of 1.3 ≦ (T1 / T2) ≦ 2.5 is established between the wall thickness T1 of the front end taper portion substantially central portion and the wall thickness T2 of the straight pipe portion substantially central portion, the rear end A relationship of 1.3 ≦ (T3 / T2) ≦ 2.5 is established between the wall thickness T3 of the side taper portion substantially central portion and the wall thickness T2 of the straight pipe portion substantially center portion, and the inside is folded while decompressing. the said stent in a contracted state on the outer surface of the straight pipe portion of the balloon The catheter of the stent but is disposed in a state of being brought into close contact with the further balloon outer surface with heat shrinkable tube, the rear side tapered portion of the distal side tapered portion and the balloon of the balloon folded while reducing the pressure inside A stent delivery catheter characterized in that axial movement is suppressed.   At the same time as the relationship of 1.6 ≦ (T1 / T2) ≦ 2.5 is established between the thickness T1 of the front end taper portion substantially central portion and the thickness T2 of the straight pipe portion substantially central portion, the rear end The relationship of 1.6 ≦ (T3 / T2) ≦ 2.5 is established between the thickness T3 of the substantially central portion of the side taper portion and the thickness T2 of the substantially central portion of the straight pipe portion. The stent delivery catheter according to 1.

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