Catheter

Abstract

The invention provides a catheter, which at least comprises a polymer layer, the polymer layer at least comprises a transition structure, the transition structure is a tubular structure, the transition structure comprises a single material area and a mixed material area, any one continuous closed area in the single material area is called as a first sub-area, and any one continuous closed area in the mixed material area is called as a second sub-area. Any one continuous closed area in the mixed material area is called as a second sub-area, any section of the transition structure in the axial direction comprises at least one second sub-area, and the starting section or the ending section of the transition structure comprises at least one first sub-area and at least one second sub-area; the edge of one end of the mixed material area is an inclined surface which forms an inclination angle with the axial direction of the conduit, and the edge of the other end is a right-angle surface perpendicular to the axial direction of the conduit.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and more specifically to catheters used for intracranial vascular interventional therapy. Background Technology

[0002] Minimally invasive interventional surgery, supported by imaging systems, uses intravascular catheter delivery systems to deliver implantable medical devices or therapeutic drugs to the lesion site with minimal trauma for mechanical or chemical treatment. Catheters, as an important component of the delivery system, have been widely used in various minimally invasive interventional procedures.

[0003] Currently, such interventional procedures typically begin with a puncture at a small blood vessel (such as the femoral or radial artery) as the entry point. The catheter is then advanced along the vessel through this entry point, guided by a sheath and guidewire, to the target lesion. During clinical procedures, due to the tortuous nature of the blood vessels, establishing the access system requires considerable time from the surgeon. However, for particularly tortuous vascular locations, such as the type III aortic arch or the ophthalmic artery within the intracranial artery, if the catheter can still be successfully delivered, intraoperative time can be significantly reduced.

[0004] Typically, a catheter consists of a three-layer structure: an inner layer, a reinforcing layer, and an outer layer. The inner and outer layers are usually made of polymer tubing, while the reinforcing layer is typically a metal or polymer filament structure embedded between the inner and outer layers. Structurally, three factors affect the catheter's flexibility: the hardness of the inner layer, the strength and coverage density of the reinforcing filament, and the hardness of the outer layer. The catheter has segments with varying hardness, being harder proximally and softer distally, with the hardness gradually decreasing from proximal to distal. The design of the hardness of different segments needs to be based on vascular anatomy. This design structure allows the catheter to be delivered to the lesion site during clinical use. The transition between hardness and softness is usually adjusted by regulating the type and hardness of the polymer material in the splicing segments, as well as the strength or pitch of the metal filament in the reinforcing layer. Commonly used polymer raw materials for the catheter body include polytetrafluoroethylene, polyurethane, polyamide, and polyolefins. Softer polymer materials (such as Pebax 25D) are used distally, while harder polymer materials (such as Pebax 72D and Nylon) are used proximally. Structurally, when the rigidity of two adjacent segments differs too much, the flexibility of the catheter will be affected. This type of design is not conducive to pushing the catheter in tortuous blood vessels and poses a certain risk of damaging blood vessels.

[0005] To meet the delivery performance requirements of catheters, it is necessary to splice polymers of different hardness to make the catheters meet the mechanical performance requirements of different blood vessel locations. The splicing methods of catheters in the existing technology do not result in a smooth transition of the mechanical properties of the catheters, thus affecting the delivery performance and safety performance of the catheters. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing catheters and catheter transition structures, in order to solve the technical problem that in existing catheters, the splicing method results in an insufficiently smooth transition of the mechanical properties of the catheter, thereby affecting the delivery performance and safety performance of the catheter.

[0007] To solve the above-mentioned technical problems, the present invention provides a catheter comprising:

[0008] At least one polymer layer, the polymer layer contains at least one transition structure, the transition structure is a tubular structure, the transition structure includes a single material region and a mixed material region, any continuous closed region in the single material region is called a first sub-region, any continuous closed region in the mixed material region is called a second sub-region, any segment of the transition structure in the axial direction contains at least one second sub-region, and the starting segment and / or ending segment of the transition structure contains at least one first sub-region and at least one second sub-region.

[0009] Optionally, any segment of the transition structure in the axial direction includes at least one first sub-region and at least one second sub-region.

[0010] Optionally, from the starting position and / or ending position of the transition structure, axially from the end to the middle region of the transition structure, the ratio of the external surface area of ​​the single material region to the mixed material region gradually decreases.

[0011] Optionally, from one end to the other, the ratio of the external surface area of ​​the single-material region to the mixed-material region in the transition structure gradually decreases to a minimum and then gradually increases.

[0012] Optionally, at least one edge of the mixed material zone is an inclined surface at an angle to the axial direction of the conduit.

[0013] Optionally, the angle between the inclined plane and the axial direction of the conduit is 5-60°.

[0014] Optionally, the edge of at least one end of the mixed material region has a wavy structure.

[0015] Optionally, the axial length of the mixed material zone is uniform, and the axial length of the mixed material zone is 1-15mm.

[0016] Optionally, the axial length of the mixed material zone is not uniform, with the axial length of the mixed material zone being 3-20 mm at its maximum and 0.5-15 mm at its minimum.

[0017] Optionally, the single-material region includes a first polymer region and a second polymer region, which are distributed on both sides of the mixed-material region. The first polymer region is composed of a first polymer material, and the second polymer region is composed of a second polymer material. The hardness of the first polymer material is greater than that of the second polymer material.

[0018] Optionally, the hardness of the mixed material region is less than that of the first polymer region, and the hardness of the mixed material region is greater than that of the second polymer region.

[0019] Optionally, at least one edge of the mixed material region is an inclined surface at an angle to the axial direction of the conduit. The greater the hardness difference between the first polymer material and the second polymer material, the smaller the inclination angle.

[0020] Optionally, the mixed material region is formed by blending and fusing a first polymer material and a second polymer material.

[0021] Optionally, the mixed material region is formed by overlapping and splicing a first polymer material and a second polymer material.

[0022] Optionally, the first polymer material is any one of polytetrafluoroethylene, polyolefin, polyurethane, polyether block polyamide, and polyamide, and the second polymer material is any one of polytetrafluoroethylene, polyolefin, polyurethane, polyether block polyamide, and polyamide.

[0023] Optionally, the catheter may also include a reinforcing layer.

[0024] Optionally, the catheter has a three-layer structure, consisting of an inner layer, a reinforcing layer, and an outer layer from the inside out. The inner and outer layers are polymer layers, and the inner and / or outer layers contain at least one transition structure.

[0025] Optionally, the inner layer includes at least one transition structure.

[0026] Optionally, the distal end of the inner layer includes at least one transition structure.

[0027] Optionally, the outer layer includes at least one transition structure.

[0028] Furthermore, the present invention also provides a method for preparing a conduit transition structure, the method comprising: cutting the tips of a first polymer tubing and a second polymer tubing such that the circumferential extension range of the tips of the first polymer tubing and / or the second polymer tubing is less than one circumferential direction, the first polymer tubing being composed of a first polymer material, the second polymer tubing being composed of a second polymer material, the hardness of the first polymer material being greater than the hardness of the second polymer material, and the tips of the first polymer tubing and the second polymer tubing being at least partially overlapped and spliced ​​before being heat-shrinked.

[0029] Optionally, the heat shrinking temperature is higher than the melting point of the first polymer material and the second polymer material.

[0030] Optionally, the heat shrinking temperature is between the melting point of the first polymer material and the melting point of the second polymer material.

[0031] Optionally, before overlapping and splicing, the ends of the first polymer tube and / or the second polymer tube are stretched so that the thickness of the ends of the first polymer tube and / or the second polymer tube is less than the thickness of the tube body.

[0032] In summary, the catheter provided by this invention includes at least one polymer layer, and the polymer layer contains at least one transition structure. The transition structure is tubular and includes a single-material region and a mixed-material region. Any continuously closed region in the single-material region is called a first sub-region, and any continuously closed region in the mixed-material region is called a second sub-region. Any segment of the transition structure in the axial direction contains at least one second sub-region, and the starting and / or ending segments of the transition structure contain at least one first sub-region and at least one second sub-region. Furthermore, this invention also provides a method for preparing the transition structure. The catheter and the method for preparing the transition structure provided by this invention have at least the following advantages:

[0033] 1. The smooth transition of the polymer material in the catheter, in terms of both hardness and mechanical properties, results in better overall mechanical properties of the catheter, thus improving its delivery performance and safety.

[0034] 2. It meets the mechanical performance requirements of the catheter in different blood vessel locations, and is less prone to bending at locations where mechanical performance changes.

[0035] 3. It makes it less likely for stress concentration points to form after splicing two materials with large differences in hardness, and can reduce the amount of polymer material in the conduit and the number of spliced ​​segments.

[0036] 4. By stretching the end of the polymer pipe to make the thickness of the splice end less than the thickness of the pipe body, the thickness at the splice position can be controlled, thus preventing the outer diameter of the conduit from being too large.

[0037] 5. The presence of mixed material zones helps to improve the splicing strength at the joint locations and enhance the safety performance of the conduit. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of a catheter provided in a preferred embodiment of the present invention;

[0039] Figure 2 This is an axial projection view of the transition structure in the catheter provided in a preferred embodiment of the present invention;

[0040] Figure 3 This is a cross-sectional view of a segment of a catheter provided in a preferred embodiment of the present invention;

[0041] Figure 4 This is an unfolded view of the transition structure in the catheter provided in a preferred embodiment of the present invention;

[0042] Figure 5This is an unfolded view of the transition structure in the catheter provided in a preferred embodiment of the present invention;

[0043] Figure 6 This is an unfolded view of the transition structure in the catheter provided in a preferred embodiment of the present invention;

[0044] Figure 7 This is an axial projection view of the transition structure in the catheter provided in a preferred embodiment of the present invention;

[0045] Figure 8 This is an unfolded view of the transition structure in the catheter provided in a preferred embodiment of the present invention;

[0046] Figure 9 This is a cross-sectional view of the catheter provided in a preferred embodiment of the present invention.

[0047] [The annotations in the attached figures are explained below]:

[0048] 100-Cavity; 200-Transition structure; 201-Starting position; 202-Ending position; 210-Starting segment; 220-Ending segment; 1-Single material region; 2-Mixed material region; 101-First polymer region; 102-Second polymer region; 1011, 1021-First sub-region; 2001-Second sub-region; 3-Proximal tube; 4-Distal tube; 1001-Inner layer; 1002-Reinforcing layer; 1003-Outer layer; 1004-Inner lumen. Detailed Implementation

[0049] To make the objectives, advantages, and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clearly illustrate the objectives of the embodiments of the present invention.

[0050] As used herein, the singular forms “a,” “an,” and “the” include plural objects, and the plural form “a plurality” includes two or more objects, unless otherwise expressly indicated. As used herein, the term “or” is generally used to include the meaning of “and / or,” unless otherwise expressly indicated; and the term “proximal” generally refers to the end closer to the operator, and the term “distal” generally refers to the end closer to the patient and the lesion, unless otherwise expressly indicated. Those skilled in the art will understand the specific meaning of the above terms in this invention according to the specific circumstances. The same or similar reference numerals in the drawings represent the same or similar parts.

[0051] Example 1

[0052] Example 1 provides a catheter 100, which includes at least one polymer layer and at least one transition structure 200. Figure 1 This is a schematic diagram of the catheter 100 provided in Embodiment 1, as shown below. Figure 1 As shown, the transition structure 200 is a tubular structure from the starting position 201 to the ending position 202. In the transition structure 200, the area between the starting position 201 and the ending position 202 is the intermediate area. The transition structure 200 includes a single material area 1 and a mixed material area 2.

[0053] Figure 2 This is an axial projection of a specific plane of the transition structure 200 in the conduit 100. Figure 2 From the shown projection viewpoint, the transition structure 200 is symmetrical front to back. In other embodiments, the transition structure 200 may also not have front-to-back symmetry in its projection viewpoint. For example... Figure 2 As shown, the single-material region 1 further includes a first polymer region 101 and a second polymer region 102. The first polymer region 101 is composed of a first polymer material, and the second polymer region 102 is composed of a second polymer material. The hardness of the first polymer material is greater than that of the second polymer material. In some other embodiments, the hardness of the first polymer material may also be less than that of the second polymer material.

[0054] Any continuous closed region in the transition structure 200 is called a sub-region. The transition structure 200 is actually a tubular structure. The sub-region is defined as follows: any continuous closed shape is selected on the outer surface of the tubular structure, and the continuous closed body obtained by "cutting" the closed shape perpendicular to the tube wall is the sub-region. Any continuous closed region in the single material region 1 is called the first sub-region 1011 (or 1021), and any continuous closed region in the mixed material region 2 is called the second sub-region 2001.

[0055] exist Figure 2 In the diagram, the area defined by the circular dashed line is a sub-region, the quadrilateral area defined by the two diagonal lines is the mixed material region 2, and the two triangular areas are the single material region 1. Single material region 1 includes a first polymer region 101 and a second polymer region 102. Any consecutive closed region within the first polymer region 101 and the second polymer region 102 is respectively the first sub-region 1011 and the first sub-region 1012. The first sub-region 1011 is located within the first polymer region 101, and the first sub-region 1012 is located within the second polymer region 102. Any consecutive closed region within the mixed material region 2 is the second sub-region 2001. Figure 2 As can be seen from this, any axial segment of arbitrary length can be selected on the transition structure 200, such as... Figure 2The area defined by the dashed line includes at least one second sub-region 2001 within the selected segment; simultaneously, within the axial region from the axial end of the first polymer region 101 of the transition structure 200 (located at the starting position 201 of the transition structure 200) to the ending position of the first polymer region 101 (located in the middle region of the transition structure 200), any axial segment of arbitrary length can be selected, such as... Figure 2 The area defined by the dashed line includes at least one first sub-region 1011 and at least one second sub-region 2001 within this segment. Similarly, within the axial region from the axial end of the second polymer region 102 (located at the end position of the transition structure 200) to the end position of the second polymer region 102 (located in the middle region of the transition structure 200), any axial segment of arbitrary length may be selected, which includes at least one first sub-region 1021 and at least one second sub-region 2001. In this embodiment, both ends of the transition structure 200 include a single-material region 1. In other embodiments, only one end of the transition structure 200 may include a first polymer region 101, or only one end may include a second polymer region 102. In this embodiment, the end of the first polymer region 101 is the starting position 201 of the transition structure 200, and the segment near the starting position 201 is the starting segment 210. It should be noted that the starting segment 210 is a shorter segment near the starting position 201, representing a segment from the starting position 201 to a selected position located in the middle region of the transition structure 200 but close to the starting position 201. The end of the second polymer region 102 is the ending position 202 of the transition structure 200, and the segment near the ending position 202 is the ending segment 220. It should be noted that the ending segment 220 is a shorter segment near the ending position 202, representing a segment from the ending position 202 to a selected position located in the middle region of the transition structure 200 but close to the ending position 202. The transition structure 200 in the catheter 100 provided in this embodiment includes at least one first sub-region 1011 (and / or first sub-region 1021) and at least one second sub-region 2001 in both the starting segment 210 and the ending segment 220; in some other embodiments, the starting segment 210 of the transition structure 200 includes at least one first sub-region 1011 (or first sub-region 1021) and at least one second sub-region 2001, while the ending segment 220 includes only at least one second sub-region 2001; or, in some other embodiments, the ending segment 220 of the transition structure 200 includes at least one first sub-region 1011 (or first sub-region 1021) and at least one second sub-region 2001, while the starting segment 210 includes only at least one second sub-region 2001.

[0056] In this embodiment, the mixed material region 2 forms an inclined tube structure, meaning that the edges at both ends of the mixed material region 2 are inclined surfaces at an angle to the axial direction of the conduit. The angles formed by the edges at both ends of the mixed material region 2 and the axial direction of the conduit can be the same or different, and the angles can be 5-60°. In some other embodiments, the mixed material region 2 may have only one edge that is an inclined surface at an angle to the axial direction of the conduit, while the edge at the other end is a right-angled surface perpendicular to the axial direction of the conduit.

[0057] The material of the mixed material region 2 can be a blend of a first polymer and a second polymer. For example, in the manufacturing process of a conduit, a one-piece tube needs to be obtained through heat shrinking. During heat shrinking, if the heat shrinking temperature reaches above the melting point of two or more materials at the contact surface where different materials come into contact, the materials can melt and penetrate each other to form a blend. The material of the mixed material region 2 can also be a composite material formed by overlapping and splicing a first polymer and a second polymer. For example, a polymer with a beveled end face is inserted into another polymer with or without a beveled end face. During the heat shrinking process, the heat shrinking temperature is controlled to be no higher than the melting point temperature of the higher melting point material, but higher than the melting point temperature of the lower melting point material. After heat shrinking, a blend will not be formed, but rather a composite material layer of two materials superimposed and bonded together. In some embodiments, the mixed material region 2 can be formed by blending and fusing a first polymer and a second polymer. In other embodiments, the mixed material region 2 can be a composite material layer formed by overlapping and bonding a first polymer and a second polymer.

[0058] In this embodiment, the hardness of the mixed material region 2 is between that of the first polymer material and the second polymer material; in other embodiments, the hardness of the mixed material region 2 is slightly higher than that of the first polymer material and the second polymer material. The presence of the mixed material region 2 helps to improve the splicing strength at the splicing position and enhance the safety performance of the catheter.

[0059] like Figure 2 As shown, in this embodiment, from the starting position 201 and ending position 202 of the transition structure 200 to the intermediate region of the transition structure 200, the ratio of the external surface area of ​​the first polymer region 101 or the second polymer region 102 to the mixed material region 2 gradually decreases; and there is a section in the intermediate region of the transition structure 200 that has only the area of ​​the mixed material region 2 in the axial direction. In other embodiments, from one end of the transition structure 200 to the other end, the ratio of the external surface area of ​​the first polymer region 101 (or the second polymer region 102) to the mixed material region 2 gradually decreases; or, in some other embodiments, from one end of the transition structure 200 to the other end, the ratio of the external surface area of ​​the first polymer region 101 (or / and the second polymer region 102) to the mixed material region 2 first decreases to a minimum value and then gradually increases.

[0060] The polymer layer of the catheter 100 provided in this embodiment contains a transition structure 200, which can make the transition of the softness, hardness and mechanical properties of the catheter 100 smooth, resulting in better overall mechanical properties of the catheter 100 and improving the delivery performance and safety performance of the catheter 100.

[0061] Meanwhile, in order to meet the mechanical performance requirements of different blood vessel locations, the catheter 100 needs to have different hardness at different locations. Therefore, it is necessary to use a variety of polymer materials with different hardness and / or different types for splicing. If the hardness difference between the two polymer materials being spliced ​​is large, the catheter 100 is prone to bending at the splicing position, resulting in a reduction in the volume of the lumen or even permanent deformation. Therefore, at least one polymer layer of the catheter 100 often requires multiple splicing of multiple polymer materials to meet the mechanical performance requirements of different blood vessel locations and achieve a smooth transition of mechanical performance. The transition structure 200 described in this embodiment at the splicing position can prevent stress concentration points from being generated after splicing of two materials with large hardness differences, and can reduce the amount of polymer material in the catheter and the number of splicing segments, while also meeting the requirements of a smooth transition of mechanical performance.

[0062] Example 2

[0063] A partial axial cross-sectional view of a conduit 100 including a transition structure 200 is shown below. Figure 3 , Figure 3 In the diagram, the area enclosed by the rectangular border is the transition structure 200. The proximal end of the transition structure 200 is the proximal tube 3, and the distal end is the distal tube 4. The proximal tube 3 is made of a first polymer material, and the distal tube 4 is made of a second polymer material. The first polymer material has a higher hardness than the second polymer material. The first polymer region 101 is the area extending from the proximal tube 3 to the distal end, the second polymer region 102 is the area extending from the distal tube 4 to the proximal end, and the mixed material region 2 is the area where the proximal tube 3 and the distal tube 4 contact or mix. For ease of distinction, Figure 3Taking the composite material layer obtained by overlapping and bonding the first polymer material and the second polymer material in the mixed material region 2 as an example, in other embodiments, the material of the mixed material region 2 can be a blended material obtained by blending and fusing the first polymer material and the second polymer material. In the transition structure 200, the edge of the mixed material region 2 and the single material region 1 is an inclined plane with an angle to the axial direction of the conduit. The angle of inclination of the inclined plane between the edge of the mixed material region 2 and the first polymer region 101 and the axial direction of the conduit is β, and the angle of inclination of the inclined plane between the edge of the mixed material region 2 and the second polymer region 102 and the axial direction of the conduit is α. The minimum axial length of the mixed material region 2 is L1, and the maximum axial length of the mixed material region 2 is L2. The values ​​of β and α can be the same or different, and the values ​​of L1 and L2 can be the same or different. When β and α are the same, L1 and L2 are the same. When the inner diameter of the catheter 100 is 0.013”~0.029”, L1 and L2 are preferably 1mm~3mm, and α and β are preferably 45°~60°; when the inner diameter of the catheter 100 is 0.055”~0.090”, L1 and L2 are preferably 6mm~15mm, and α and β are preferably 5°~60°. In some other embodiments, L1 and L2 can be 0.5-20mm. In some embodiments, the axial length of the mixed material region is uniform, i.e., L1 and L2 are the same, and the values ​​of L1 and L2 are 1-15 mm, such as 1 mm, 3 mm, 5 mm, 7.5 mm, 10 mm, 12 mm, 15 mm, etc.; in some embodiments, the axial length of the mixed material region is not uniform, i.e., L1 and L2 are not the same, and the value of L1 is 0.5-15 mm, such as 0.5 mm, 2 mm, 5 mm, 6 mm, 8 mm, 11 mm, 12.5 mm, 15 mm, etc., and the value of L2 is 3-20 mm, such as 3 mm, 5 mm, 7 mm, 10 mm, 12 mm, 15 mm, 17.5 mm, 20 mm, etc.

[0064] Figure 3 The unfolded view of the transition structure 200 after being cut along the axial direction is shown in the figure. Figure 4 , Figure 4 This more intuitively shows the positions of L1, L2, α, and β and the relationships between them. Figure 4 In this embodiment, the axial cut-off position is the location where the axial length of the mixed material region 2 is minimum. The transition structure 200 is a symmetrical structure. Figure 4 As can be seen from the diagram, after being cut along the axial direction, the unfolded view of the transition structure 200 is symmetrical vertically; for example... Figure 5 As shown, in some other embodiments, the transition structure 200 may not be a symmetrical structure, such as the end position of the first polymer region 101 ( Figure 5 The right vertex of the left triangle in the middle) and the end position of the second polymer region 102 ( Figure 5 The line connecting the rightmost intersection point to the conduit axis is not parallel to the conduit axis. Figure 4 As can be seen, within the transition structure 200, an axial segment of arbitrary length is selected, and this selected segment necessarily includes a second sub-region 2001. Within the axial region from the axial end of the first polymer region 101 (located at the starting position 201 of the transition structure 200) to the end position of the first polymer region 101 (located in the middle region of the transition structure 200), any axial segment of arbitrary length is selected, and this segment includes at least one first sub-region 1011 and at least one second sub-region 2001. Within the axial region from the axial end of the second polymer region 102 (located at the end position 202 of the transition structure 200) to the end position of the second polymer region 102 (located in the middle region of the transition structure 200), any axial segment of arbitrary length is selected, and this segment includes at least one first sub-region 1021 and at least one second sub-region 2001. In this embodiment, the angles α and β are different, but neither is 90°. In other embodiments, the angles α and β can be the same, but neither is 90°. In other embodiments, when β is not 90°, α can be 90°. In this case, the transition structure 200 contains only the first polymer region 101 and the mixed material region 2. In the axial region from the axial end of the first polymer region 101 (located at the starting position 201 of the transition structure 200) to the end position of the first polymer region 101 (located in the middle region of the transition structure 200), any axial segment of arbitrary length can be selected. This segment contains at least one first sub-region 1011 and at least one second sub-region 2001. Similarly, when α is not 90°, β can be 90°. In this case, the transition structure 200 contains only the second polymer region 102 and the mixed material region 2. Within the axial region from the axial end of the second polymer region 102 (located at the end position 202 of the transition structure 200) to the end position of the second polymer region 102 (located in the middle region of the transition structure 200), any axial segment of arbitrary length can be selected. This segment includes at least one first sub-region 1021 and at least one second sub-region 2001. In this embodiment, α and β have the same orientation; in other embodiments, α and β may have different orientations, for example, α may be oriented towards the end position 202 of the transition structure 200, and β towards the beginning position 201 of the transition structure 200, or vice versa. It should be noted that in this embodiment, α and β refer to the angle of inclination of the slope between the end edge of the mixed material region 2 and the axial direction of the conduit. This angle is acute, and α and β do not refer to obtuse angles complementary to this angle.

[0065] With the same catheter inner diameter, the greater the difference between angles α and β, the greater the difference between L1 and L2. To ensure a smooth transition in the hardness of the catheter 100, and to prevent the catheter 100 from bending at the transition position, in a preferred embodiment of the invention, the greater the hardness difference between the first polymer material and the second polymer material, the smaller the controlled tilt angles α and / or β. The smaller the controlled tilt angles α and / or β, the smoother the material change at the transition position of the catheter 100, and the smoother the trend of the change in the mechanical properties of the catheter 100, which is beneficial to the delivery performance and safety of the catheter 100 in tortuous blood vessels.

[0066] In this embodiment, the transition structure 200 has an axial segment containing only the second sub-region 2001, without the first sub-region 1011 (or 1021). Figure 6 As shown, in some other embodiments, any axial segment in the transition structure 200 includes at least one first sub-region 1011 (and / or first sub-region 1021) and at least one second sub-region 2001.

[0067] Example 3

[0068] The catheter 100 provided in Embodiment 3 includes at least one transition structure 200, and a schematic diagram of the transition structure 200 is shown below. Figure 7 The transition structure 200 provided in Embodiment 3 includes a single material region 1 and a mixed material region 2. The single material region 1 further includes a first polymer region 101 and a second polymer region 102. The first polymer region 101 is composed of a first polymer material, and the second polymer region 102 is composed of a second polymer material. The hardness of the first polymer material is higher than that of the second polymer material. The first polymer region 101 and the second polymer region 102 are located on both sides of the mixed material region 2.

[0069] The edges of the mixed material region 2 in the transition structure 200 exhibit a stepped structure (or rectangular wave-like structure) in the axial projection direction of a specific plane. In this embodiment, the edges of both ends of the mixed material region 2 in the axial direction contain a stepped structure; in other embodiments, the mixed material region 2 of the transition structure 200 may contain a stepped structure only at one end.

[0070] In the transition structure 200 of the catheter 100 provided in Embodiment 3, any axial segment can be selected, such as... Figure 7The area defined by the dashed line includes at least one second sub-region 2001 in the selected segment. Simultaneously, within the axial region from the axial end of the first polymer region 101 of the transition structure 200 (located at the starting position 201 of the transition structure 200) to the ending position of the first polymer region 101 (located in the middle region of the transition structure 200), any axial segment of arbitrary length can be selected, as shown in the area defined by the dashed line. This segment includes at least one first sub-region 1011 and at least one second sub-region 2001. Similarly, within the axial region from the axial end of the second polymer region 102 (located at the ending position 202 of the transition structure 200) to the ending position of the second polymer region 102 (located in the middle region of the transition structure 200), any axial segment of arbitrary length can be selected, and this segment includes at least one first sub-region 1021 and at least one second sub-region 2001.

[0071] Figure 7 The unfolded view of the transition structure 200 after being cut along the axial direction is shown in the figure. Figure 8 ,from Figure 8 It can be seen from this that Figure 7 The transition structure 200 is a symmetrical tube structure. In some other embodiments, the transition structure 200 is an asymmetrical tube structure.

[0072] In some other embodiments, the edge of any one end or both ends of the mixed material region 2 can be a wavy structure. The wavy structure can be, but is not limited to, a triangular wavy structure, a rectangular wavy structure, a square wavy structure, a sinusoidal wavy structure, an irregular wavy structure, etc.

[0073] The other structures are similar to those in Embodiment 1, and will not be described in detail here.

[0074] Example 4

[0075] The axial and radial cross-sectional views of the catheter 100 provided in Example 4 are shown below. Figure 9 ,like Figure 9 As shown, an inner layer 1001, a reinforcing layer 1002, and an outer layer 1003 are sequentially arranged radially from the inside to the outside of the conduit 100. The reinforcing layer 1002 is sleeved outside the inner layer 1001, and the outer layer 1003 covers the reinforcing layer 1002. The inner layer 1001 defines the inner lumen 1004 of the conduit 100. The inner layer 1001 and the outer layer 1003 are polymer layers. In some other embodiments, the conduit 100 includes only the outer layer 1003 and the inner layer 1001, excluding the reinforcing layer 1002; or, the conduit 100 includes only one polymer layer; or, the conduit 100 includes only one polymer layer and the reinforcing layer 1002.

[0076] The outer layer 1003 is a polymer layer. In embodiments of the present invention, the material of the outer layer 1003 is selected from at least one of polyamide, polyolefin, polyether block polyamide, and polyurethane. In this embodiment, the material of the outer layer 1003 includes polyamide, polyether block polyamide, polyurethane, and polyolefin, and the outer layer 1003 is spliced ​​from the above materials. In embodiments of the present invention, the reinforcing layer 1002 is composed of a metallic material or a polymer material, and its function is to improve the strength, support performance, lumen collapse resistance, force transmission, and torsional control transmission of the conduit 100. In this embodiment, the reinforcing layer 1002 is composed of a metallic material. The inner layer 1001 is a polymer layer. In embodiments of the present invention, the material of the inner layer 1001 includes at least one of polytetrafluoroethylene, polyolefin, polyurethane, and polyether block polyamide. In this embodiment, the material of the inner layer 1001 includes polytetrafluoroethylene and polyolefin, and the splicing position of the materials in the inner layer 1001 includes any one of the transition structures 200 described in Embodiments 1 to 3. In embodiments of the present invention, the catheter 100 comprises at least one polymer layer, and the at least one polymer layer contains any one of the transition structures 200 described in Embodiments 1 to 3. In other embodiments, the catheter 100 comprises only one polymer layer, which contains any one of the transition structures 200 described in Embodiments 1 to 3; or, the catheter 100 comprises two polymer layers: an inner layer 1001 and an outer layer 1003, wherein the inner layer 1001 and / or the outer layer 1003 contains any one of the transition structures 200 described in Embodiments 1 to 3; or, the catheter 100 comprises two or more polymer layers, and at least one polymer layer contains any one of the transition structures 200 described in Embodiments 1 to 3.

[0077] In this embodiment, the inner layer 1001 is divided into a first inner layer segment located at the proximal end and a second inner layer segment located at the distal end. The material of the first inner layer segment is a first polymer material, and the material of the second inner layer segment is a second polymer material. The hardness of the first polymer material is greater than that of the second polymer material. In embodiments of the present invention, the hardness of the first polymer material is 40D-70D, and its material may be, but is not limited to, polytetrafluoroethylene (PTFE). In this embodiment, the hardness of the first polymer material is 60D, and its material is PTFE. In other embodiments, the hardness of the first polymer material may be 40D, 45D, 50D, 54D, 62D, 65D, 66D, 68D, or 70D. The hardness of the second polymer material is 30A-55D, and the material can be, but is not limited to, any one or a mixture of several of polyolefins, polyether block polyamides, and polyurethanes. In this embodiment, the second polymer material is a polyolefin with a hardness of 35D. In other embodiments, the second polymer material is linear low-density polyethylene or a polyolefin elastomer, a polyether block polyamide with added lubricant, or a polyurethane with added lubricant. In other embodiments, the hardness of the second polymer material can be 30A, 40A, 45A, 60A, 70A, 80A, 90A, 30D, 35D, 38D, 40D, 50D, or 55D. In embodiments of the present invention, the length of the first inner layer segment is 1000-1550mm, and the length of the second inner layer segment is 50-600mm. In this embodiment, the length of the first inner layer segment is 1100mm, and the length of the second inner layer segment is 350mm.

[0078] In other embodiments, the constituent materials of the first inner layer segment and / or the second inner layer segment may also be a blend of several polymeric materials, or a polymer mixed with inorganic substances such as developing metal powder; in some other embodiments, the materials of the first inner layer segment and / or the second inner layer segment are a blend of polyolefin and polyether block polyamide in a 1:1 ratio; in some other embodiments, the materials of the first inner layer segment and / or the second inner layer segment are a blend of polyolefin and polyurethane in a 2:1 ratio; in some other embodiments, the materials of the first inner layer segment and / or the second inner layer segment are polyether block polyamide and polyurethane. In some embodiments, the materials of the first inner layer segment and / or the second inner layer segment are blends of polyolefin, polyether block polyamide, and polyurethane in a ratio of 1:1:1; in some embodiments, the materials of the first inner layer segment and / or the second inner layer segment are blends of linear low-density polyethylene and polyolefin elastomer in a ratio of 1:1; in some embodiments, the materials of the first inner layer segment and / or the second inner layer segment are linear low-density polyethylene mixed with tungsten powder, the polymer mixed with tungsten powder can provide the imaging performance of the catheter 100 body. In some embodiments, the materials of the first inner layer segment and / or the second inner layer segment are polyether block polyamide with added lubricant; in some embodiments, the materials of the first inner layer segment and / or the second inner layer segment are polyurethane with added lubricant; in some embodiments, the materials of the first inner layer segment and / or the second inner layer segment are a mixture of polyether block polyamide with added lubricant and polyurethane in a ratio of 1:1.

[0079] In one embodiment, the length of the first inner layer segment is 1000 mm and the length of the second inner layer segment is 170 mm; in other embodiments, the length of the first inner layer segment is 1550 mm and the length of the second inner layer segment is 50 mm; in other embodiments, the length of the first inner layer segment is 1150 mm and the length of the second inner layer segment is 600 mm; in other embodiments, the length of the first inner layer segment is 200 mm and the length of the second inner layer segment is 1200 mm.

[0080] Example 5

[0081] Example 5 provides a method for preparing the transition structure 200 in any of the conduits 100 described in Examples 1 to 4. The preparation method provided in Example 5 is as follows: the ends of the first polymer tubing and the second polymer tubing are cut so that the circumferential extension range of the ends of the first polymer tubing and / or the second polymer tubing is less than one circumferential direction. The first polymer tubing is composed of a first polymer material, and the second polymer tubing is composed of a second polymer material. The hardness of the first polymer material is greater than the hardness of the second polymer material. The ends of the first polymer tubing and the ends of the second polymer tubing are at least partially overlapped and spliced, and then heat-shrinked to obtain the transition structure 200.

[0082] Although the preparation method provided in Example 5 is a method for preparing the transition structure 200, the transition structure 200 is actually generated during the preparation of the conduit 100 (or the polymer layer of the conduit 100), and is not prepared separately for use in the conduit 100. For example, the first polymer tubing is actually the proximal tubing (raw material) of the inner layer 1001 of the conduit, and the second polymer tubing is actually the distal tubing (raw material) of the inner layer 1001 of the conduit. After processing the first polymer tubing and the second polymer tubing using the above preparation method, the inner layer 1001 of the conduit 100 is actually obtained, and the transition structure 200 exists at the material transition position of the inner layer 1001; or, for a multilayer conduit structure, the head end of any polymer tubing of any polymer layer can be cut, and then assembled as a whole and heat-shrinked. After heat-shrinking, the overall structure of the conduit 100 is actually obtained, and the transition structure 200 exists at the material transition position of the polymer layer in the conduit 100.

[0083] In this embodiment, the heat shrinking temperature is between the melting point of the first polymer material and the melting point of the second polymer material. After heat shrinking, the mixed material region 2 in the transition structure 200 is formed by overlapping and splicing the first polymer material and the second polymer material, and the material of the mixed material region 2 is a composite material. In other embodiments, the heat shrinking temperature is higher than the melting points of the first polymer material and the second polymer material. After heat shrinking, the mixed material region 2 is formed by blending and fusing the first polymer material and the second polymer material, and the material of the mixed material region 2 is a blended material.

[0084] In some other implementations, before cutting the ends of the first and second polymer tubing, or after cutting the ends of the first and second polymer tubing and before overlapping them, the ends of the first and / or second polymer tubing can be stretched to make their thickness less than the body thickness. This stretched end thickness, being less than the body thickness, results in a smaller thickness at the splicing point after the tubing ends are joined. Controlling the thickness at the splicing point allows for a more uniform overall size of the conduit 100, avoiding abrupt changes in outer diameter. This further smooths the transition of the overall mechanical properties of the conduit 100, improving its pushing performance. Furthermore, for certain materials, stretching within a certain range can increase their strength. Stretching before splicing improves the strength of the material transition points, making them less prone to breakage.

[0085] While the present invention has been disclosed above, it is not limited thereto. Those skilled in the art can make various modifications and variations to the present invention without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims and their equivalents, the present invention also intends to include such modifications and variations.

Claims

1. A catheter, characterized in that: It comprises at least one polymer layer, and the polymer layer comprises at least one transition structure, which is a tubular structure. The transition structure includes a single-material region and a mixed-material region. Any continuous closed region in the single-material region is called a first sub-region, and any continuous closed region in the mixed-material region is called a second sub-region. Any segment of the transition structure in the axial direction contains at least one second sub-region. The starting or ending segment of the transition structure contains at least one first sub-region and at least one second sub-region. The edge of one end of the mixed-material region is an inclined plane with an angle to the axial direction of the conduit, and the edge of the other end is a right-angled plane perpendicular to the axial direction of the conduit.

2. The catheter as described in claim 1, characterized in that, From the starting or ending position of the transition structure, axially from the end to the middle region of the transition structure, the ratio of the outer surface area of ​​the single material region to that of the mixed material region gradually decreases.

3. The catheter as described in claim 1, characterized in that, The angle between the inclined plane and the axial direction of the conduit is 5-60°.

4. The catheter as described in claim 1, characterized in that, The axial length of the mixed material zone is uneven, with the maximum axial length being 3-20 mm and the minimum axial length being 0.5-15 mm.

5. The catheter as described in claim 1, characterized in that, The proximal end of the transition structure is a proximal tube, and the distal end of the transition structure is a distal tube. The material of the proximal tube is a first polymer material, and the material of the distal tube is a second polymer material. The hardness of the first polymer material is greater than that of the second polymer material.

6. The catheter as described in claim 5, characterized in that, The hardness of the mixed material region is less than that of the first polymer region, and the hardness of the mixed material region is greater than that of the second polymer region.

7. The catheter as described in claim 5, characterized in that, The hardness of the mixed material region is higher than that of the first polymer region and the second polymer region.

8. The catheter as described in claim 5, characterized in that, The mixed material region is formed by blending and fusing the first polymer material and the second polymer material, or the mixed material region is formed by overlapping and splicing the first polymer material and the second polymer material.

9. The catheter as claimed in claim 1, characterized in that, The catheter also includes a reinforcing layer.

10. The catheter as claimed in claim 1, characterized in that, The catheter has a three-layer structure, consisting of an inner layer, a reinforcing layer, and an outer layer from the inside out. The inner layer and the outer layer are polymer layers, and the inner layer and / or the outer layer contains at least one of the transition structures.

11. The catheter as claimed in claim 10, characterized in that, The inner layer contains at least one of the transition structures.

12. The catheter as claimed in claim 11, characterized in that, The distal end of the inner layer includes at least one of the transition structures.

13. The catheter as claimed in claim 10, characterized in that, The outer layer includes at least one of the transition structures.

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