JP2012029872A - Catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catheter which has a reinforcement structure by braiding, places a low burden on a blood vessel, has smooth reachability, and has sufficient pressing property as a rigidity on the proximal side is enhanced.SOLUTION: An outer diameter of a shaft of the catheter 10 contracts toward a distal end part 26 side. A reinforcement layer 34 (braid 35) provided in the shaft 12 has a first spiral part 38 and a second spiral part 50 different in spiral direction from each other. The number of windings of a second spiral part is larger than that of a first spiral part. Pitch ratio (P2/P1) between pitches P1, P2 of the first spiral part 38 and the second spiral part 40 is smaller towards the distal end part 26 side.

Description

  The present invention relates to a catheter having a reinforcing layer constituted by a braid in which thin wires are folded.

  A catheter is used to insert a therapeutic tip or a diagnostic contrast agent into a blood vessel or body cavity so that the tip of the catheter reaches a target site. For this reason, it is necessary for the catheter shaft to be selectively advanced along a guide wire introduced in advance in a blood vessel or a body cavity that is complicatedly branched in the body, and is used for injection of a therapeutic drug or imaging for diagnosis. It is necessary to have excellent agent injection characteristics.

  For example, in the treatment of liver cancer, in order to preserve the normal region, it is required to insert a catheter only into a blood vessel (nutrient blood vessel) feeding nutrients to cancer cells and inject a drug. If the diameter is large, there is a concern that it does not enter the blood vessel or stimulates the blood vessel to cause spasm. On the other hand, a clear angiography is necessary to identify the nutrient blood vessels, and in order to inject a contrast medium in a sufficient amount per unit time, or in the treatment, a highly viscous oil-based contrast medium is injected by hand injection. A large lumen is required for the catheter. Thus, the catheter has conflicting demands that the outer diameter is narrow and the lumen is large.

  Since such characteristics are required for the catheter, the proximal side ensures rigidity and pushability while ensuring the drug or contrast agent injection characteristics, and the distal end side is made flexible so that it is flexible to the peripheral blood vessels. Ingenuity to improve reachability and followability to the guide wire has been made.

  In recent years, in order to reduce medical accidents, a catheter having a reinforcing structure with a braid (blade) formed by folding a wire such as a metal wire is aimed at increasing the lumen strength of the catheter and increasing the breaking strength of the catheter itself. Usage is increasing. A catheter having such a reinforcing structure is disclosed in Patent Documents 1 and 2 below, for example.

JP-T-2006-515778 JP 2008-183226 A

  However, a catheter having a braided reinforcing structure has a problem that it is difficult to give sufficient flexibility to the distal end portion of the catheter due to the presence of the braid. In particular, with the recent development of diagnostic devices, it has become possible to find smaller peripheral cancers, and more catheters have been advanced into the peripheral meandering blood vessels than ever before, placing a burden on the blood vessels. No smooth reachability is required. Therefore, there is a demand for a catheter having a braided reinforcing structure that becomes stiffer from the distal end to the hand as well as the flexibility of the distal end portion of the catheter.

  In general, it is known that the braided body improves the performance of the catheter in terms of axial compression strength, torque transmission, etc., but the flexibility required to advance the bent part There was a problem that would be damaged.

  The present invention has been made in view of the above circumstances, and in a catheter having a braided reinforcing structure, the burden on the blood vessel is small, smooth reachability is obtained, and sufficient rigidity is achieved by increasing the rigidity on the proximal side. An object of the present invention is to provide a catheter that can be obtained.

  In order to achieve the above object, the present invention provides a catheter having a shaft formed with a lumen communicating from the distal end to the proximal end, wherein the shaft has a constant outer diameter in the axial direction. A distal end portion having a constant outer diameter in the axial direction and having an outer diameter smaller than the outer diameter of the proximal end portion, and a portion from the proximal end of the distal end portion to the distal end of the proximal end portion. And an intermediate portion whose outer diameter decreases toward the distal end side, and the shaft is provided with a reinforcing layer composed of a braid in which fine wires are woven from the proximal end portion to the distal end portion. The braid includes a first spiral portion made of one or more wires wound in a first spiral direction, and one or more wound in a second spiral direction different from the first spiral direction. Consists of a second spiral portion made of wire and arranged to intersect And the number of windings of the wire constituting the second spiral portion is larger than the number of windings of the wire constituting the first spiral portion, and the pitch of the first spiral portion at the distal end portion is at the base end portion. The pitch of the first spiral portion is smaller than the pitch of the first spiral portion, the pitch of the first spiral portion at the intermediate portion is smaller than the pitch of the first spiral portion at the proximal end portion, and the first spiral portion at the distal end portion. The pitch of the second spiral portion at the distal end portion is smaller than the pitch of the second spiral portion at the proximal end portion, and the second spiral portion at the intermediate portion is the proximal end portion. The pitch of the first spiral portion is P1 and the pitch of the second spiral portion is P2, which is smaller than the pitch of the second spiral portion and larger than the pitch of the second spiral portion at the tip. In this case, the pitch ratio (P2 / P1) is the largest at the proximal end portion, the smallest at the distal end portion, and a size between the proximal end portion and the distal end portion at the intermediate portion. .

  According to said structure, since a lumen | bore and an outer diameter become small as it goes to a front-end | tip part from a base end part, although the lumen | bore near the front-end | tip of a catheter is thin, sufficient lumen | bore can be ensured in the base side of a catheter. . For this reason, it is possible to reduce the outer diameter of the catheter tip, and it is also possible to easily inject a high-viscosity contrast agent (for example, an oil-based contrast agent) by hand injection. In addition, since the number of windings of the wire rods of the first spiral portion and the second spiral portion is different, compared to the case where the number of windings is the same, the catheter itself is structured to bend and has a braided reinforcing layer. It is possible to provide a catheter with a very soft tip while maintaining the advantages of lumen retention and high breaking strength. Furthermore, since the pitch becomes wider from the distal end of the catheter toward the proximal side, sufficient flexibility can be secured at the distal end portion, and moderate hardness can be secured at the proximal side. Furthermore, since the pitch ratio (P2 / P1) is also reduced stepwise toward the tip, the rigidity can be set more finely and easily in each part. Therefore, according to the catheter of the present invention, the burden on the blood vessel is small and smooth reachability can be obtained, and the rigidity on the hand side can be increased to provide sufficient pushability.

  In the above catheter, each pitch of the first spiral portion and the second spiral portion at the proximal end portion may be set so as to decrease stepwise toward the distal end side.

  According to the above configuration, the proximal side has a high rigidity on the proximal side and becomes softer toward the distal end side, and the rigidity (hardness) changes in stages, so smooth reachability and sufficient Therefore, it is possible to suitably ensure a good pushability.

  In the catheter, five sections are set in the proximal end portion along the axial direction, and the pitches of the first spiral section and the second spiral section are set for each section, It is better that the pitch is smaller as the section is closer.

  According to the above configuration, five pitches are set in each of the first spiral portion and the second spiral portion, and the pitch is smaller in the section on the distal end side, so the flexibility on the distal end side and the rigidity on the proximal side are reduced. The balance can be set more finely, and both smooth reachability and sufficient pushability can be improved more suitably.

  In the above-described catheter, it is preferable that a reduction rate of the pitch toward the distal end side of the shaft with respect to the second spiral portion is larger than that of the first spiral portion.

  According to said structure, a front-end | tip part becomes easier to bend and the softness | flexibility of a front-end | tip part can be improved further. For this reason, a catheter with better reachability can be realized.

  In the catheter described above, a ratio (N1 / N2) of the number N1 of the wires constituting the first spiral portion and the number N2 of the wires constituting the second spiral portion may be ½. In addition, the number of wire rods constituting the first spiral portion may be four, and the number of wire rods constituting the second spiral portion may be eight. In this way, by configuring the first spiral portion and the second spiral portion by changing the number of windings of the wire, it is possible to adopt a structure in which flexible portions and rigid portions are alternately arranged. It is possible to achieve the compressive strength in the axial direction, which is a feature of the braid, and the flexibility that has been a problem.

  According to the catheter of the present invention, the burden on the blood vessel is small, smooth reachability is obtained, and the rigidity on the proximal side is increased to obtain sufficient pushability.

1 is a partially omitted overall configuration diagram of a catheter according to an embodiment of the present invention. It is the one part omission schematic diagram of the shaft which is one component of the catheter. It is sectional drawing along the III-III line in FIG. It is a figure which shows the structure of the braid which comprises the reinforcement layer provided in the shaft. The result of having measured the pitch of the 1st spiral part and the pitch of the 2nd spiral part for every section about the example of the catheter according to Table 1 is shown. It is a graph which shows the result of having measured the pitch ratio (P2 / P1) of a 1st spiral part and a 2nd spiral part for every Example about the Example of the catheter according to Table 1. FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a catheter according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a partially omitted overall configuration diagram of a catheter 10 according to an embodiment of the present invention. The catheter 10 is inserted into a blood vessel or a body cavity so that the distal end of the catheter 10 reaches a target site, and is used to inject a therapeutic drug or a diagnostic contrast medium. As shown in FIG. 1, the catheter 10 includes a thin and long shaft 12, a hub 14 connected to the proximal end of the shaft 12, and a strain relief 16 provided at a connection portion of the shaft 12 to the hub 14. With.

  In the following description, regarding the shaft 12, the hub 14 side is also referred to as a proximal end side, and the side opposite to the side to which the hub 14 is connected is also referred to as a distal end side, and the same applies to other drawings.

  The shaft 12 is a tubular member having flexibility in which a lumen 18 (see FIG. 2) communicating from the distal end to the proximal end is formed. The length of the shaft 12 is about 500 mm to 2000 mm, preferably about 1000 mm to 1500 mm. The inner diameter and outer diameter of the shaft 12 will be described later.

  An X-ray opaque marker (contrast marker) 22 is fixed to the outer peripheral surface of the most distal end portion of the shaft 12. The radiopaque marker 22 is formed of a material having radiopacity made of gold, platinum, or the like, so that the distal end position of the catheter 10 can be viewed in vivo under radiography. Is. The X-ray opaque marker 22 is not limited to the configuration provided to be exposed on the outer peripheral surface, but may be embedded in the tube wall of the shaft 12. The most distal portion of the shaft 12 may have a taper.

  The hub 14 holds the proximal end of the shaft 12 at its distal end, and other instruments such as a syringe can be connected to the proximal end. The strain relief 16 is for preventing bending (kinking) at the connection portion of the shaft 12 to the hub 14. For example, the strain relief 16 is formed of a resin having moderate flexibility and rigidity formed in a tapered tube shape. It is a member.

  FIG. 2 is a partially omitted schematic view of the shaft 12. 2 shows the schematic shape of the shaft 12, the dimensional ratio between the outer diameter and the length does not necessarily match that of the shaft 12 shown in FIG. As shown in FIG. 2, the shaft 12 includes a proximal end portion 24 constituting the proximal end side, a distal end portion 26 constituting the distal end side, and an intermediate portion 28 constituting between the proximal end portion 24 and the distal end portion 26. Have

  The base end portion 24 is a portion constituting a section from the position C to the position H (the most base end position of the shaft 12) shown in FIG. 2 in the shaft 12, and the outer diameter is constant in the axial direction. . The distal end portion 26 is a portion constituting a section from the position A (the most advanced position of the shaft 12) to the position B in the shaft 12, and the outer diameter is constant in the axial direction and the outer diameter is the base end. The outer diameter of the portion 24 is smaller.

  The intermediate portion 28 is a portion constituting a portion from the position B (the base end of the distal end portion 26) to the position C (the distal end of the proximal end portion 24), and decreases in diameter toward the distal end portion 26 side. The intermediate portion 28 is not limited to the configuration shown in FIG. 2 that decreases in diameter toward the distal end portion 26 at a constant ratio, and may have a configuration that decreases exponentially toward the distal end portion 26 side.

  The length of the base end portion 24 (the length from the position C to the position H) is set to, for example, about 200 mm to 1800 mm, and preferably set to about 400 mm to 1300 mm. The outer diameter of the base end portion 24 is set, for example, to about 0.5 mm to 3.0 mm, and preferably about 0.7 mm to 2.0 mm. The inner diameter of the base end portion 24 (the lumen diameter at the base end portion 24) is set to, for example, about 0.4 mm to 2.0 mm, and preferably about 0.5 mm to 1.6 mm.

  The length of the distal end portion 26 (the length from the position A to the position B) is set to, for example, about 3 mm to 300 mm, and preferably about 10 mm to 150 mm. The outer diameter of the distal end portion 26 is set to, for example, about 0.4 mm to 2.0 mm, preferably about 0.6 mm to 1.6 mm. The inner diameter of the distal end portion 26 (the lumen diameter in the distal end portion 26) is set to, for example, about 0.2 mm to 1.5 mm, and preferably set to about 0.4 mm to 1.2 mm.

  The length of the intermediate portion 28 (the length from the position B to the position C) is set to, for example, about 5 mm to 500 mm, and preferably about 20 mm to 100 mm. The distal end outer diameter of the intermediate portion 28 is set to be the same as the outer diameter of the distal end portion 26, and the proximal end outer diameter of the intermediate portion 28 is set to be the same as the outer diameter of the proximal end portion 24. The inner diameter of the intermediate portion 28 (the lumen diameter in the intermediate portion 28) coincides with the inner diameter of the distal end portion 26 on the distal end side, and coincides with the inner diameter of the proximal end portion 24 on the proximal end side, and in the meantime, toward the distal end portion 26 side. To reduce the diameter.

  3 is a cross-sectional view taken along line III-III in FIG. As shown in FIG. 3, the shaft 12 includes an inner layer 30 in which the lumen 18 is formed, an outer layer 32 formed on the radially outer side of the inner layer 30, and a reinforcing layer 34 provided along the outer periphery of the inner layer 30. Have

  The inner layer 30 and the outer layer 32 can be made of a synthetic resin having appropriate flexibility. Examples of the constituent material of the inner layer 30 include PFA (a copolymer of tetrafluoroethylene and perfluoroalkoxyethylene). Examples of the constituent material of the outer layer 32 include polyamide elastomer. Of course, the inner layer 30 and the outer layer 32 may be made of other materials. The cross-sectional shapes of the inner layer 30 and the outer layer 32 in a natural state (a state where no external force is applied) are substantially circular.

  FIG. 4 is a partially enlarged side view of the shaft 12, and the outer layer is shown by phantom lines in order to facilitate understanding of the configuration of the reinforcing layer 34 provided along the outer periphery of the inner layer 30. As shown in FIG. 4, the reinforcing layer 34 is configured by a mesh-like braid 35 (blade) in which fine lines are interwoven, and is provided over the entire length of the shaft 12. The braid 35 includes a first spiral portion 38 composed of one or more wire rods 38a wound in a first spiral direction, and one or more wire rods wound in a second spiral direction different from the first spiral direction. The second spiral portion 40 made of 40a is arranged so as to intersect.

  Examples of the constituent material of the wires 38a and 40a constituting the braid 35 include metals, polymers, composites of metals and polymers, metal alloys (for example, stainless steel), and combinations thereof. The number of windings (referred to as N2) of the wire rod 40a constituting the second spiral portion 40 is greater than the number of windings (referred to as N1) of the wire rod 38a constituting the first spiral portion 38. In the configuration example shown in FIG. 4, the ratio of N1 and N2 (N1 / N2) = 1/2. Of course, N1 / N2 may be other ratios such as 1/3, 2/3, etc. depending on the specification of the catheter 10 and the like.

  Specifically, the winding number N1 of the wire rod 38a constituting the first spiral portion 38 is four, and the winding number N2 of the wire rod 40a constituting the second spiral portion 40 is eight. With this configuration, the catheter 10 of the present invention achieves a desired effect. Of course, the winding numbers N1 and N2 can be appropriately increased or decreased with respect to the above-described number depending on the specifications of the catheter 10 or the like.

  The wire rod 40a constituting the second spiral portion 40 is arranged so that a large interval and a small interval are alternately repeated in the axial direction, and the small interval is defined as a pitch P2 of the second spiral portion 40 in the present invention. As shown in FIG. 4, the pitch (referred to as P <b> 1) of the first spiral portion 38 is larger than the pitch P <b> 2 of the second spiral portion 40. The pitch refers to the distance in the axial direction of the spiral portion wound around the catheter 10.

  The width (thickness) W of the wire constituting the first spiral portion 38 and the second spiral portion 40 is set to, for example, about 5 μm to 200 μm, and preferably about 15 μm to 100 μm. In the present embodiment, the width of the wire rod 38a of the first spiral portion 38 and the width of the wire rod 40a of the second spiral portion 40 are the same, but may be different widths. The cross-sectional shape of the wires 38a and 40a may be circular, elliptical, or rectangular.

  As for the 1st spiral part 38 and the 2nd spiral part 40 in the base end part 24, pitch P1, P2 becomes small gradually toward the front end side. In the present embodiment, five sections (section CD, section DE, section EF, section FG, section GH) are set in the base end portion 24 along the axial direction, and the first spiral section 38 and the second spiral section. The pitches P1 and P2 of 40 are set for each section, and the pitches P1 and P2 are smaller in the section on the distal end portion 26 side.

  Further, the pitch P 1 of the first spiral portion 38 at the distal end portion 26 is smaller than the pitch P 1 of the first spiral portion 38 at the proximal end portion 24. The pitch P1 of the first spiral portion 38 in the intermediate portion 28 is smaller than the pitch P1 of the first spiral portion 38 in the proximal end portion 24 and larger than the pitch P1 of the first spiral portion 38 in the distal end portion 26.

  Further, the pitch P2 of the second spiral portion 40 in the distal end portion 26 is smaller than the pitch P2 of the second spiral portion 40 in the proximal end portion 24, and the pitch P2 of the second spiral portion 40 in the intermediate portion 28 is the proximal end portion. 24, which is smaller than the pitch P2 of the second spiral portion 40 at 24 and larger than the pitch P2 of the second spiral portion 40 at the distal end portion 26.

  In the present embodiment, the decreasing rate of the pitch P <b> 2 toward the distal end portion 26 side of the shaft 12 with respect to the second spiral portion 40 is larger than that of the first spiral portion 38.

Specifically, the pitches P1 and P2 of the first spiral portion 38 and the second spiral portion 40 in the section AB (tip portion) are P1 _AB and P2 _AB , respectively, and the first spiral portion 38 and the second spiral portion in the section GH. when the pitch P1, P2 of 40 was distinguished from _P1 GH, _{P2 GH respectively,} P2 AB / _{P2 GH is} less than _P1 AB / P1 _GH.

  Further, the second spiral portion 40 is larger than the first spiral portion 38 in the pitch reduction rate of the portion (section CD to section BC) that transitions from the base end portion 24 to the intermediate portion 28. Similarly, the second spiral portion 40 is larger than the first spiral portion 38 in terms of the pitch reduction rate of the portion (section BC to section AB) that transitions from the intermediate section 28 to the tip section 26.

  In the present embodiment, the pitch ratio (P2 / P1) is not constant, is the largest at the proximal end portion 24, is smallest at the distal end portion 26, and is between the proximal end portion 24 and the distal end portion 26 at the intermediate portion 28. Is the size of

  Table 1 below shows an example of setting the inner layer outer diameter for each section in the catheter 10, the pitch P1 of the first spiral portion 38, the pitch P2 of the second spiral portion 40, and the length when the catheter 10 is configured according to the above. . Of course, these dimensions can be appropriately changed according to the specifications of the catheter 10 or the like. For example, in Table 1, the length of the section GH is 895 mm, which is the case of the catheter 10 having the total length of the shaft 12 of about 130 cm + α, but in the case of the catheter 10 in which the total length of the shaft 12 is increased or decreased. Increases or decreases the length of the section GH by the increase or decrease, and the other sections may be the same as in Table 1.

  FIG. 5 shows the results of measuring the pitch P1 of the first spiral portion 38 and the pitch P2 of the second spiral portion 40 for each section for the example of the catheter 10 according to Table 1. As apparent from FIG. 5, the pitch P <b> 1 of the first spiral portion 38 and the pitch P <b> 2 of the second spiral portion 40 are smaller in the intermediate portion 28 than in the base end portion 24 and smaller in the distal end portion 26 than in the intermediate portion 28. . Moreover, in the base end part 24, the pitches P1 and P2 are different for each section, and the pitches P1 and P2 are smaller as they are closer to the distal end part 26 side.

  FIG. 6 is a graph showing the results of measuring the pitch ratio (P2 / P1) between the first spiral portion 38 and the second spiral portion 40 for each section for the example of the catheter 10 according to Table 1. As apparent from FIG. 6, the pitch ratio (P2 / P1) is smaller in the intermediate portion 28 than in the proximal end portion 24 and smaller in the distal end portion 26 than in the intermediate portion 28.

  In Table 1, since the pitch P1 of the first spiral portion 38 in the section GH is 360 μm and the pitch P1 of the first spiral section 38 in the section AB is 120 μm, the rate of change is about 0.33 ( = 120/360). On the other hand, since the pitch of the second spiral portion 40 in the section GH is 170 μm and the pitch of the second spiral section 40 in the section AB is 40 μm, the change rate is about 0.26 (= 40/170). ). Therefore, as described above, the rate of decrease in the pitch of the second spiral portion 40 toward the tip portion 26 of the shaft 12 is larger than that of the first spiral portion 38.

  Moreover, in Table 1, when the ratio of the change of the part (section CD to section BC) which transfers from the base end part 24 to the intermediate part 28 is seen, the 1st spiral part 38 is about 0.94 (= 160/170), The second spiral portion 40 is about 0.86 (= 60/70), and the second spiral portion 40 has a larger pitch reduction rate than the first spiral portion 38.

  Similarly, in Table 1, when the rate of change of the portion (section BC to section AB) transitioning from the intermediate section 28 to the tip section 26 is seen, the first spiral section 38 is about 0.75 (= 120/160), The second spiral portion 40 is about 0.67 (= 40/60), and the pitch reduction rate of the second spiral portion 40 is larger than that of the first spiral portion 38.

  The catheter 10 according to an embodiment of the present invention is basically configured as described above, and the operation and effect thereof will be described below.

  In the catheter 10 configured as described above, since the lumen 18 and the outer diameter decrease from the proximal end portion 24 toward the distal end portion 26, the lumen 18 near the distal end of the catheter 10 is narrow, but the catheter 10 A sufficient lumen 18 can be secured on the root side. For this reason, the outer diameter of the distal end of the catheter 10 can be reduced, and a high-contrast contrast agent (for example, an oil-based contrast agent) can be easily injected by hand injection.

  In addition, since the number of windings of the wire rods of the first spiral portion 38 and the second spiral portion 40 is different, the catheter 10 itself tends to bend as compared with the case where the number of windings is the same, and the reinforcing layer formed by the braid 35 It is possible to provide the catheter 10 with a very soft tip 26 while maintaining the lumen retention and high breaking strength, which are the advantages of having 34.

  Further, since the pitches P1 and P2 are widened from the distal end of the catheter 10 toward the proximal side, sufficient flexibility can be secured at the distal end portion 26, and moderate hardness can be secured at the proximal side.

  Furthermore, the pitch ratio (P2 / P1) at the intermediate portion 28 is smaller than the pitch ratio (P2 / P1) at the base end portion 24, and the tip end is larger than the pitch ratio (P2 / P1) at the intermediate portion 28. The pitch ratio (P2 / P1) at the portion 26 is configured to be smaller, and not only the pitches P1 and P2, but also the pitch ratio (P2 / P1) is decreased stepwise toward the tip side. Therefore, the setting of rigidity in each part can be performed more finely and easily. Therefore, it is possible to realize a catheter that can easily obtain sufficient flexibility of the distal end portion.

  Therefore, according to the catheter 10 of the present invention, the burden on the blood vessel is small, smooth reachability is obtained, and the rigidity on the hand side can be increased to provide sufficient pushability.

  Moreover, since the decreasing rate of the pitch P2 toward the front end portion 26 side of the shaft 12 with respect to the second spiral portion 40 is larger than that of the first spiral portion 38, the front end portion 26 is more easily bent, Flexibility can be further improved. For this reason, the catheter 10 with much better reachability can be realized.

  In the catheter 10 according to the present embodiment, the pitches of the first spiral portion 38 and the second spiral portion 40 at the proximal end portion 24 are set so as to decrease stepwise toward the distal end portion 26 side. In the base end portion 24, the proximal side has a high rigidity and becomes softer toward the distal end portion 26 side, so that the rigidity (hardness) changes in stages. For this reason, it is possible to suitably ensure smooth reachability and sufficient pushability.

  In particular, in the catheter 10 according to this embodiment, five pitches are respectively set in the first spiral portion 38 and the second spiral portion 40, and the pitch is smaller in the section on the distal end portion 26 side. The balance between the flexibility and the rigidity on the hand side can be set more finely, and both smooth reachability and sufficient pushability can be improved more suitably.

[Example]
The catheter 10 was manufactured by changing the number of the wires 38a and 40a of the first spiral portion 38 and the second spiral portion 40. The manufactured catheter 10 was evaluated for axial compressive strength, axial flexibility, and peripheral reachability in a blood vessel model. The results are shown in Table 2 below. In Table 2, a circle symbol indicates “good”, and a triangle symbol indicates “normal”.

  As is clear from Table 2, the catheter 10 in which the number of the wire rods 40a and 38a of the second spiral portion 40 and the first spiral portion 38 is 8 and 4, respectively, was excellent in all evaluations.

  In the above description, the present invention has been described with reference to preferred embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. Needless to say.

DESCRIPTION OF SYMBOLS 10 ... Catheter 12 ... Shaft 18 ... Lumen 24 ... Base end part 26 ... Tip part 28 ... Intermediate | middle part 34 ... Reinforcement layer 35 ... Braid 38 ... 1st spiral part 38a, 40a ... Wire rod 40 ... 2nd spiral part

Claims (6)

A catheter having a shaft formed with a lumen communicating from the distal end to the proximal end;
The shaft is
A proximal end portion having a constant outer diameter in the axial direction;
A distal end portion whose outer diameter is constant in the axial direction and whose outer diameter is smaller than the outer diameter of the base end portion;
A portion from the proximal end of the distal end portion to the distal end of the proximal end portion, comprising an intermediate portion whose outer diameter decreases toward the distal end side;
The shaft is provided with a reinforcing layer composed of a braid in which fine wires are woven from the proximal end portion to the distal end portion,
The braid includes a first spiral portion made of one or more wires wound in a first spiral direction, and one or more wire rods wound in a second spiral direction different from the first spiral direction. The second spiral portion is arranged to intersect with each other,
The winding number of the wire constituting the second spiral portion is larger than the winding number of the wire constituting the first spiral portion,
The pitch of the first spiral portion at the distal end portion is smaller than the pitch of the first spiral portion at the proximal end portion,
The pitch of the first spiral portion in the intermediate portion is smaller than the pitch of the first spiral portion in the proximal end portion and larger than the pitch of the first spiral portion in the distal end portion,
The pitch of the second spiral portion at the distal end portion is smaller than the pitch of the second spiral portion at the proximal end portion,
The second spiral portion in the intermediate portion is smaller than the pitch of the second spiral portion in the proximal end portion and larger than the pitch of the second spiral portion in the distal end portion,
When the pitch of the first spiral portion is P1 and the pitch of the second spiral portion is P2, the pitch ratio (P2 / P1) is the largest at the proximal end portion, the smallest at the distal end portion, and the intermediate portion. In the portion, the size is between the base end and the tip.
A catheter characterized by that. The catheter of claim 1,
Each pitch of the first spiral portion and the second spiral portion at the base end portion is set so as to decrease stepwise toward the distal end side.
A catheter characterized by that. The catheter of claim 2,
In the base end, five sections are set along the axial direction,
The pitch of the first spiral portion and the second spiral portion is set for each section, and the pitch is smaller toward the tip side section,
A catheter characterized by that. The catheter according to any one of claims 1 to 3,
The pitch decreasing rate toward the tip end side of the shaft with respect to the second spiral portion is larger than that of the first spiral portion,
A catheter characterized by that. The catheter according to any one of claims 1 to 4,
The ratio (N1 / N2) of the number N1 of wires constituting the first spiral portion and the number N2 of wires constituting the second spiral portion is 1/2.
A catheter characterized by that. The catheter of claim 5,
The number of wires constituting the first spiral portion is four, and the number of wires constituting the second spiral portion is eight.
A catheter characterized by that.

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