CN115430004A

CN115430004A - Intravascular access catheter

Info

Publication number: CN115430004A
Application number: CN202110626390.3A
Authority: CN
Inventors: 许永松; 郭琦; 唐航; 王金磊; 廖芝美; 吴健
Original assignee: BEIJING TAIJIE WEIYE TECHNOLOGY CO LTD
Current assignee: BEIJING TAIJIE WEIYE TECHNOLOGY CO LTD
Priority date: 2021-06-04
Filing date: 2021-06-04
Publication date: 2022-12-06

Abstract

The application discloses an intravascular access catheter, which comprises a catheter body, a stress relief catheter and a catheter seat; one end of the tube body is fixedly connected with one end of the stress relief tube, and the other end of the stress relief tube is fixedly connected with the tube seat; the body comprises most advanced, development mark, gentle soft section, time soft section, changeover portion and rigidity near-end, most advanced one end is equipped with the development mark, development mark one end is equipped with soft section, soft section one end is equipped with time soft section, time soft section one end is equipped with the changeover portion, just changeover portion one end is equipped with the rigidity near-end. The catheter can achieve high in-place performance of intracranial blood vessels, can enable supporting instruments to reach lesion parts more frequently, can ensure that pushing force in an operation can be smoothly conducted from a near end to a far end in the pushing process, cannot cause the phenomenon that the far end of the catheter bounces in the blood vessels, and can reduce damage to the inner walls of the blood vessels to the maximum extent.

Description

Intravascular access catheter

Technical Field

The application relates to the technical field of vascular interventional therapy, in particular to an intravascular access catheter.

Background

With the continuous development of the nerve intervention technology, the clinical application puts higher requirements on the access product of the interventional therapy. For intracranial interventional surgery, the support catheter is required to reach farther positions of blood vessels and be closer to a treatment area, so that stronger support is provided for matched diagnosis or treatment instruments. The traditional guide catheter has limited reaching position due to size reasons, and cannot meet clinical requirements, so that a novel access catheter appears in the market in recent years. The passageway pipe needs the trafficability characteristic good, high in place often can reach the sponge sinus section, can reach the middle and upper section of middle cerebral artery even, M2 section or basilar artery, and the main function is for providing better support nature for the pipe distal end that declines, for the thrombus capture device provides bigger passageway or for the high in place of intracranial sacculus pipe provides assurance etc. the appearance of passageway pipe has brought very big facility for the clinic, has greatly reduced the condition that leads to the intervention treatment to fail because of the difficulty of entrying.

The access catheter on the market still has certain defects, for example, because the inner diameter of the inner cavity of the access catheter is larger than that of the nerve microcatheter, when the catheter passes through a tortuous section in an intracranial blood vessel, the catheter is easy to cause clinical problems such as folding, local loss or collapse of the lumen, difficulty in passing through a specific tortuous part, poor transmission of pushing force, bounce at the distal end of the catheter and the like. Accordingly, an intravascular access catheter is proposed to address the above-mentioned problems.

Disclosure of Invention

An intravascular access catheter comprises a catheter body, a stress relief catheter and a catheter seat;

one end of the tube body is fixedly connected with one end of the stress relief tube, and the other end of the stress relief tube is fixedly connected with the tube seat; the tube body comprises a tip, a development mark, a soft section, a secondary soft section, a transition section and a rigid near end, wherein the development mark is arranged at one end of the tip, the soft section is arranged at one end of the development mark, the secondary soft section is arranged at one end of the soft section, the transition section is arranged at one end of the secondary soft section, and the rigid near end is arranged at one end of the transition section;

the soft section, the secondary soft section and the transition section are all composed of a first inner layer, a first middle layer, a second middle layer and an outermost layer, the first middle layer is positioned on the outer side of the first inner layer, the second middle layer is positioned on the outer side of the first middle layer, and the outermost layer is positioned on the outer side of the second middle layer; the rigid proximal end is comprised of a second inner layer, a third intermediate layer, and an outer layer, the third intermediate layer being located outboard of the second inner layer, and the outer layer being located outboard of the third intermediate layer.

Further, the length of the tip is 0.3-1.0mm, the material of the tip can be silica gel, pebax, polyurethane elastomer and the like, and preferably, the material of the tip is silica gel.

Further, the soft section has 1-2 hardness gradients, the outermost layer is made of polyurethane elastomer or Pebax material, preferably, the outermost layer is made of polyurethane elastomer, and the length of the soft section is 3-8cm; the secondary soft section has 2-3 hardness gradients, the material of the outermost layer at the section is Pebax material or polyurethane elastomer with different brands, and the length of the secondary soft section is 5-10cm; the transition section is provided with 2-3 hardness gradients, the material of the outermost layer at the section is Pebax material or polyurethane elastomer with different brands, and the length of the transition section is 5-15cm.

Further, the rigid proximal end has a 1 hardness gradient, the outer layer at the section is made of Pebax material or PA material, preferably, the outer layer is made of PA material, and the length of the rigid proximal end is 60-100cm.

Further, the first inner layer and the second inner layer are both PTFE inner layers, and the inner diameter of the tube body ranges from 0.03 inches to 0.09 inches.

Further, the first intermediate layer is a winding structure, and the axial length of the winding structure penetrates through the soft section, the secondary soft section and the transition section; the soft segment, the secondary soft segment, and the first intermediate layer have relatively uniform pitch, and the transition segment to the first intermediate layer has a gradually decreasing pitch.

Further, the second intermediate layer axially penetrates through the soft section, the secondary soft section and the transition section, the second intermediate layer is composed of a polymer fixing layer or a metal braided tube layer, and the second intermediate layer is preferably the metal braided tube layer; the polymer fixing layer is made of polyurethane, pebax or polyester fiber materials, the metal braided tube layer is provided with a braided tube structure, the metal material is nickel-titanium alloy or stainless steel, and the PPI of the braided tube structure is set to be 100-300.

Furthermore, the third middle layer adopts a metal winding structure or a weaving structure, and the selected material is nickel-titanium alloy or stainless steel; if the third middle layer adopts a metal winding structure, the third middle layer and the first middle layer can be in a segmented structure or a continuous and integrated winding structure.

Further, if the third middle layer adopts a woven structure and the second middle layer is a polymer fixing layer, the first middle layer and the third middle layer are in close butt joint or partially overlapped lap joint at the near end of the transition section.

Further, if the third intermediate layer and the second intermediate layer are both metal woven layers, the third intermediate layer and the second intermediate layer may be of a segmented structure or a continuous integral woven structure.

Through the above-mentioned embodiment of this application, adopted unique structural design, the different sections of pipe adopt the section structural design of differentiation, and the tip is the individual layer design promptly, and gentle section, time soft section and changeover portion are four layers of designs, and the rigidity near-end is the three-layer design, and the pipe inner chamber is whole unanimous design, and the external diameter is reducing or whole unanimous design.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.

FIG. 1 is a schematic overall perspective view of an embodiment of the present application;

fig. 2 is a schematic structural view of a tube according to an embodiment of the present application;

FIG. 3 is a cross-sectional end view of a tip according to one embodiment of the present application;

FIG. 4 is a cross-sectional end view of the soft segment, sub-soft segment, and transition segment of one embodiment of the present application;

FIG. 5 is a rigid proximal end cross-sectional view of one embodiment of the present application;

FIG. 6 is a schematic view of a winding configuration according to an embodiment of the present application;

FIG. 7 is a schematic view of a braided tube structure according to an embodiment of the present application.

In the figure: 1. tube body, 2, stress relief tube, 3, tube seat, 4, tip, 5, development mark, 6, soft section, 7, secondary soft section, 8, transition section, 9, rigid near end, 10, first inner layer, 11, first intermediate layer, 12, second intermediate layer, 13, outermost layer, 14, second inner layer, 15, third intermediate layer, 16, outer layer, 17, winding structure, 18, braided tube structure.

Detailed Description

In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It should be understood that the data so used may be interchanged under appropriate circumstances such that embodiments of the application described herein may be used. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

In this application, the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings. These terms are used primarily to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to a particular orientation or to be constructed and operated in a particular orientation.

Moreover, some of the above terms may be used to indicate other meanings besides the orientation or positional relationship, for example, the term "on" may also be used to indicate some kind of attachment or connection relationship in some cases. The specific meaning of these terms in this application will be understood by those of ordinary skill in the art as the case may be.

Furthermore, the terms "mounted," "disposed," "provided," "connected," and "coupled" are to be construed broadly. For example, it may be a fixed connection, a removable connection, or a unitary construction; can be a mechanical connection, or an electrical connection; may be directly connected, or indirectly connected through intervening media, or may be in internal communication between two devices, elements or components. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as the case may be.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

The access catheter in this embodiment can be applied to various vascular interventional treatment devices, for example, a cardiovascular interventional treatment device is provided in this embodiment, and the access catheter in this embodiment can be used to assist the cardiovascular interventional treatment device.

The cardiovascular and cerebrovascular interventional therapy device comprises a device main body, the lower end outer surface of the device main body is provided with a universal wheel, the upper end outer surface of the universal wheel is provided with a material box, the upper end outer surface of the material box is provided with a material box II, the upper end outer surface of the material box II is provided with a material box III, the upper end outer surface of the material box III is provided with an alcohol cotton containing tank, one side of the alcohol cotton containing tank is provided with a telescopic rod III, the upper end outer surface of the telescopic rod III is provided with a telescopic rod II, one end outer surface of the telescopic rod II is provided with a telescopic rod I, one end of the telescopic rod I is provided with a puncture catheter head, the upper end outer surface of the alcohol cotton containing tank is provided with a protective cover, the outer surface of the alcohol cotton containing tank is provided with a tank body, the outer surface of the telescopic rod III is provided with a spring resetting device, one side outer surface of the spring resetting device is provided with a fixing bolt, the outer surface of the telescopic rod II is provided with a fixing hole, the upper end outer surface of the puncture catheter head is provided with a limiting groove, the lower end outer surface of the replaceable puncture catheter head is provided with a sponge disinfection ring, the upper end outer surface of the universal wheel body, the lower end of the connecting rod is provided with a brake shaft body.

A first fixing groove is formed between the alcohol cotton containing tank and the third material box, and the outer wall of the alcohol cotton containing tank is detachably connected with the outer surface of the upper end of the third material box through the first fixing groove, so that the alcohol cotton can be replaced conveniently; the inner wall of the third telescopic rod is movably connected with the outer wall of the third telescopic rod through a fixing bolt, so that the length of the telescopic rod can be adjusted conveniently; a second fixing groove is formed between the puncture catheter head and the replaceable sponge disinfection ring, and the outer surface of the lower end of the puncture catheter head is detachably connected with the outer wall of the replaceable sponge disinfection ring through the second fixing groove, so that the puncture catheter is favorably disinfected; the outer surface of the upper end of the universal wheel is movably connected with the outer surface of the lower end of the first material box through a connecting rod, so that the device can move conveniently; the outer surface of the upper end of the third material box is provided with a storage disc, and the outer surface of the upper end of the third material box is detachably connected with the outer surface of the lower end of the storage disc, so that the storage disc is favorably stored.

Of course, the embodiment can also be used for the auxiliary use of other vascular interventional therapy devices. The following description will be made of the access conduit according to the embodiments of the present application, which will not be repeated herein.

Referring to fig. 1-7, an intravascular access catheter includes a catheter body 1, a stress relief tube 2, and a tube holder 3;

one end of the tube body 1 is fixedly connected with one end of the stress relief tube 2, and the other end of the stress relief tube 2 is fixedly connected with the tube seat 3; the tube body 1 comprises a tip 4, a developing mark 5, a soft section 6, a secondary soft section 7, a transition section 8 and a rigid near end 9, wherein the developing mark 5 is arranged at one end of the tip 4, the soft section 6 is arranged at one end of the developing mark 5, the secondary soft section 7 is arranged at one end of the soft section 6, the transition section 8 is arranged at one end of the secondary soft section 7, and the rigid near end 9 is arranged at one end of the transition section 8;

the soft section 6, the secondary soft section 7 and the transition section 8 are all composed of a first inner layer 10, a first middle layer 11, a second middle layer 12 and an outermost layer 13, wherein the first middle layer 11 is positioned on the outer side of the first inner layer 10, the second middle layer 12 is positioned on the outer side of the first middle layer 11, and the outermost layer 13 is positioned on the outer side of the second middle layer 12; the rigid proximal end 9 is constituted by a second inner layer 14, a third intermediate layer 15 and an outer layer 16, the third intermediate layer 15 being located outside the second inner layer 14 and the outer layer 16 being located outside the third intermediate layer 15.

The length of the tip 4 is 0.3-1.0mm, the tip 4 can be made of silica gel, pebax, polyurethane elastomer and other materials, and the preferred tip 4 is made of silica gel; the soft section 6 has 1-2 hardness gradients, the outermost layer 13 is made of a polyurethane elastomer or a Pebax material, preferably, the outermost layer 13 is made of a polyurethane elastomer, and the length of the soft section 6 is 3-8cm; the secondary soft section 7 has 2-3 hardness gradients, the material of the outermost layer 13 at the section is Pebax material or polyurethane elastomer with different brands, and the length of the secondary soft section 7 is 5-10cm; the transition section 8 has 2-3 hardness gradients, the material of the outermost layer 13 at the section is Pebax material or polyurethane elastomer with different brands, and the length of the transition section 8 is 5-15cm; the rigid proximal end 9 has 1 hardness gradient, the material of the outer layer 16 at this section is Pebax material or PA material, preferably, the outer layer 16 is made of PA material, and the length of the rigid proximal end 9 is 60-100cm; the first inner layer 10 and the second inner layer 14 are both PTFE inner layers, and the inner diameter of the pipe body 1 ranges from 0.03 inch to 0.09 inch; the first intermediate layer 11 is a winding structure 17, and the axial length of the winding structure penetrates through the soft section 6, the secondary soft section 7 and the transition section 8; the soft segment 6, the secondary soft segment 7 and the first intermediate layer 11 have relatively uniform pitches, and the transition segment 8 to the first intermediate layer 11 have gradually changed pitches from small pitches to large pitches, which is beneficial to provide a more optimized catheter segment, and an end segment with relatively large pitches has softer characteristics, while the gradual change of pitches in the transition segment 8 can make the hardness of the segment slowly change; the second intermediate layer 12 also axially penetrates through the flexible section 6, the secondary flexible section 7 and the transition section 8, the second intermediate layer 12 is composed of a polymer fixing layer or a metal woven tube layer, and preferably, the second intermediate layer 12 is the metal woven tube layer; the polymer fixing layer is made of polyurethane, pebax or polyester fiber materials, the metal braided tube layer is provided with a braided tube structure 18, the metal materials are nickel-titanium alloy or 304 stainless steel, and the PPI of the braided tube structure 18 is set to be 100-300; in order to reduce the thickness of the tube wall to a greater extent, the metal wire used for weaving the tube is preferably in a flat wire form (the thickness of the flat wire is in the range of 0.0005-0.003 "and the width is in the range of 0.001" -0.004 "), because the distal soft segment 6 is easy to break and cause the lumen collapse when the large-lumen catheter passes through a tortuous blood vessel, the second intermediate layer 12 is designed to improve the bending resistance of the catheter from the soft segment 6 to the transition segment 8, and in case of bending, on one hand, the first intermediate layer 11 can serve as a support lumen, and on the other hand, the second intermediate layer 12 makes the form of the first intermediate layer 11 more stable and difficult to break; the third intermediate layer 15 adopts a metal winding structure 17 or a braided structure, and is made of nickel-titanium alloy or 304 stainless steel; if the third intermediate layer 15 adopts a metal winding structure 17, the third intermediate layer 15 and the first intermediate layer 11 may be of a segmented structure, or may be of a continuous integral winding structure 17; if the third middle layer 15 adopts a woven structure and the second middle layer 12 is a polymer fixing layer, the first middle layer 11 and the third middle layer 15 are in close butt joint or partial overlapping joint at the near end of the transition section 8; if the third intermediate layer 15 and the second intermediate layer 12 are both metal woven layers, the third intermediate layer 15 and the second intermediate layer 12 may be of a segmented structure or a continuous integral woven structure.

When the flexible catheter is used, the flexible section 6 and the secondary flexible section 7 can ensure that the catheter tip 4 can better adapt to the tortuous blood vessel form, and the excellent passing performance is realized; the soft section 6, the secondary soft section 7 and the transition section 8 adopt a four-layer design, so that the catheter tip 4 can have excellent bending resistance;

when the large-cavity catheter passes through a tortuous blood vessel, the flexible section 6 at the far end is easy to bend to cause the collapse of an official cavity, so that the design of the second intermediate layer 12 is used for improving the bending resistance of the catheter from the flexible section 6 to the transition section 8, and under the condition of bending, on one hand, the first intermediate layer 11 can play a role in supporting the lumen and is not easy to ovalize, and on the other hand, the second intermediate layer 12 enables the first intermediate layer 11 to be more stable in shape and not easy to bend;

the transition section 8 to the first intermediate layer 11 has a gradually changing pitch from small to large, which is beneficial to provide a more optimized catheter section, and an end section with a relatively large pitch has a softer characteristic, while the transition section 8 with a gradually changing pitch to smaller can make the hardness of the section slowly change; the primary determinant of the overall stiffness of the catheter is that the tip 17 and the first intermediate layer 11 facilitate better retention of the lumen integrity of the catheter in a flexed condition.

The application has the advantages that:

1. the catheter can achieve high in-place performance of intracranial blood vessels, can enable matched instruments to reach lesion positions more frequently, can ensure that the pushing force in the operation can be smoothly transmitted from a near end to a far end in the pushing process, cannot cause the phenomenon that the far end of the catheter bounces in the blood vessels, can reduce the damage to the inner walls of the blood vessels to the maximum extent, and meanwhile, when the catheter passes through extremely tortuous blood vessels, the inner cavity of the catheter has complete holding capacity, and can be better compatible with matched instruments or other media;

2. the catheter adopts unique structural design, different sections of the catheter adopt differentiated section structural design, namely the tip is designed in a single layer mode, the soft section, the secondary soft section and the transition section are designed in four layers, the rigid near end is designed in three layers, the inner cavity of the catheter is designed in a uniform whole process, and the outer diameter of the inner cavity of the catheter is designed in a variable diameter or uniform whole process;

3. the hardness gradient of the whole tube body is designed to be 7-10 hardness gradients, so that the hardness of the catheter can be gradually increased from the tip to the near end, the transmission of the pushing force of the catheter from the near end to the far end can be better ensured, and the excellent pushing performance is reflected; the soft section and the secondary soft section can ensure that the distal end of the catheter can better adapt to the tortuous blood vessel form and show excellent passing performance; the soft section, the secondary soft section and the transition section adopt four-layer design, so that the far end of the catheter can have excellent bending resistance.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An intravascular access catheter, comprising: comprises a pipe body (1), a stress relief pipe (2) and a pipe seat (3);

one end of the tube body (1) is fixedly connected with one end of the stress relief tube (2), and the other end of the stress relief tube (2) is fixedly connected with the tube seat (3); the tube body (1) is composed of a tip (4), a development mark (5), a soft section (6), a secondary soft section (7), a transition section (8) and a rigid near end (9), the development mark (5) is arranged at one end of the tip (4), the soft section (6) is arranged at one end of the development mark (5), the secondary soft section (7) is arranged at one end of the soft section (6), the transition section (8) is arranged at one end of the secondary soft section (7), and the rigid near end (9) is arranged at one end of the transition section (8);

the soft section (6), the secondary soft section (7) and the transition section (8) are all composed of a first inner layer (10), a first middle layer (11), a second middle layer (12) and an outermost layer (13), the first middle layer (11) is positioned on the outer side of the first inner layer (10), the second middle layer (12) is positioned on the outer side of the first middle layer (11), and the outermost layer (13) is positioned on the outer side of the second middle layer (12); the rigid proximal end (9) is constituted by a second inner layer (14), a third intermediate layer (15) and an outer layer (16), the third intermediate layer (15) being located outside the second inner layer (14) and the outer layer (16) being located outside the third intermediate layer (15).

2. An intravascular access catheter according to claim 1, wherein:

the length of the tip (4) is 0.3-1.0mm, the tip (4) can be made of silica gel, pebax, polyurethane elastomer and the like, and the preferred tip (4) is made of silica gel.

3. An intravascular access catheter according to claim 1, wherein:

the soft section (6) has 1-2 hardness gradients, the outermost layer (13) is made of polyurethane elastomer or Pebax material, preferably, the outermost layer (13) is made of polyurethane elastomer, and the length of the soft section (6) is 3-8cm; the secondary soft section (7) has 2-3 hardness gradients, the material of the outermost layer (13) at the section is Pebax material or polyurethane elastomer with different brands, and the length of the secondary soft section (7) is 5-10cm; the transition section (8) has 2-3 hardness gradients, the material of the outermost layer (13) at the section is Pebax material or polyurethane elastomer with different brands, and the length of the transition section (8) is 5-15cm.

4. An intravascular access catheter according to claim 1, wherein:

the rigid proximal end (9) has 1 hardness gradient, the material of the outer layer (16) at the section is Pebax material or PA material, preferably, the outer layer (16) is made of PA material, and the length of the rigid proximal end (9) is 60-100cm.

5. An intravascular access catheter according to claim 1, wherein:

the first inner layer (10) and the second inner layer (14) are PTFE inner layers, and the inner diameter of the pipe body (1) is 0.03-0.09 inches.

6. An intravascular access catheter according to claim 1, wherein:

the first intermediate layer (11) is a winding structure (17) the axial length of which penetrates the soft segment (6), the secondary soft segment (7) and the transition segment (8); the soft segment (6), the secondary soft segment (7) and the first intermediate layer (11) have a relatively uniform pitch, and the transition segment (8) to the first intermediate layer (11) has a gradually changing to smaller pitch.

7. An intravascular access catheter according to claim 1, wherein:

the second middle layer (12) axially penetrates through the soft section (6), the secondary soft section (7) and the transition section (8) in the same way, the second middle layer (12) is composed of a macromolecule fixing layer or a metal woven tube layer, and the second middle layer (12) is preferably the metal woven tube layer; the high polymer fixing layer is made of polyurethane, pebax or polyester fiber materials, the metal braided tube layer is provided with a braided tube structure (18), the metal materials are nickel-titanium alloy or 304 stainless steel, and the PPI of the braided tube structure (18) is set to be 100-300.

8. An intravascular access catheter according to claim 1, wherein:

the third middle layer (15) adopts a metal winding structure (17) or a weaving structure, and the selected material is nickel-titanium alloy or 304 stainless steel; if the third intermediate layer (15) adopts a metal winding structure (17), the third intermediate layer (15) and the first intermediate layer (11) can be in a segmented structure or a continuous integral winding structure (17).

9. An intravascular access catheter according to claim 8, wherein:

if the third middle layer (15) adopts a woven structure and the second middle layer (12) is a polymer fixing layer, the first middle layer (11) and the third middle layer (15) are in close butt joint or partial overlapping joint at the near end of the transition section (8).

10. An intravascular access catheter according to claim 9, wherein:

if the third intermediate layer (15) and the second intermediate layer (12) are both metal woven layers, the third intermediate layer (15) and the second intermediate layer (12) may be of a segmented structure or a continuous integral woven structure.