A hemodialysis catheter

Abstract

The application provides a hemodialysis catheter, belonging to the field of hemodialysis equipment, which comprises a cylindrical tube body and a partition plate, a lumen is arranged in the tube body along the axial direction thereof, a tip structure is arranged at the distal end of the tube body and is communicated with the lumen, the partition plate divides the lumen into two groups of blood passages arranged side by side along the axial direction, the tip structure comprises two groups of side grooves which are arranged in a central symmetry with the central axis of the lumen as the center, the two groups of side grooves are respectively communicated with the two groups of blood passages, and the side grooves are sequentially provided with a first straight section, a curved smooth transition section and a second straight section along the axial direction of the tube body from the distal end opening. The side-hole-free design of the tip structure improves the thrombus setting risk of the conventional side-hole tip, and the risk of introducing lateral blood flow to stimulate the blood vessel wall, and the smooth and gradual narrowing and the central symmetric design of the side groove are used to synergistically optimize the hemodynamic performance, solve the problem of high recirculation rate of the side-hole-free tip, and thus improve the survival rate of the catheter and the treatment effect of hemodialysis.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of hemodialysis equipment, in particular to a hemodialysis catheter. BACKGROUND

[0002] Chronic renal failure is a progressive renal injury caused by primary or secondary renal disease, which is manifested as a series of symptoms or metabolic disorders. The main treatment for end-stage renal failure is dialysis and kidney transplantation. Hemodialysis is the main method of maintenance renal replacement therapy in China at present, and a hemodialysis catheter is generally used as a vascular access. During hemodialysis, the arterial blood in the body is introduced into the dialyzer through the hemodialysis catheter, and the purified blood is still returned to the venous blood vessel in the body through the hemodialysis catheter.

[0003] The hemodialysis catheter currently used in clinical practice is mainly made of polyurethane or silicone, but there are still two major technical problems in actual application. The first is the problem of hemodynamics: the catheter often has poor blood introduction during use. When stable blood flow cannot be maintained, the clinical operation specification recommends reversing the use of the catheter arterial and venous ports. However, if the catheter tip is designed asymmetrically, this operation will cause the recirculation rate to increase significantly (i.e., part of the purified blood does not pass through the body circulation but directly enters the arterial end from the venous end), which seriously affects the dialysis efficiency and treatment adequacy. The second is the problem of catheter blockage: the blockage mechanism mainly includes two types, one of which is mechanical blockage, which is manifested as positional blockage caused by the catheter tip being covered in the surrounding tissue, and the other is thrombotic blockage, which is manifested as the formation of a complex clot composed of fibrin, platelets and blood cells in the lumen, which will cause partial or complete loss of catheter function when the blockage reaches a critical level.

[0004] Therefore, the existing hemodialysis catheter usually adopts a double-lumen separation and spiral symmetric tip design, and in order to solve the problem of high recirculation, a side hole is usually provided near the outlet of the catheter tip (see Figure 20 and Figure 21 ). However, the blood flow shear stress at the position of the side hole is high, the blood flow at the side hole has a large scouring on the blood vessel wall, and the side hole can easily cause thrombus deposition in the side hole and may cause leakage of the catheter locking fluid, thereby increasing the risk of thrombotic blockage. In addition, the spiral symmetric tip design is usually designed in the shape of a local sharp corner, which causes a high shear stress area in the local area of the catheter tip, easily activates platelets, and aggravates mechanical hemolysis and thrombus formation. SUMMARY

[0005] Based on this, the purpose of the present application is to provide a hemodialysis catheter, aiming to improve the hemodynamic performance of blood entering the hemodialysis catheter by designing a new tip structure of the hemodialysis catheter, to reduce the recirculation rate when the catheter is connected in positive and negative directions, to reduce the probability of thrombosis and catheter location blockage, and to improve the survival rate of the hemodialysis catheter and the treatment effect of hemodialysis as a whole.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: a hemodialysis catheter, comprising a cylindrical tube body, a partition plate, a lumen being provided in the tube body along the axial direction thereof, a tip structure being provided at the distal end of the tube body and being in communication with the lumen, and the partition plate being provided in the lumen to separate the lumen into two groups of blood passages arranged side by side along the axial direction of the tube body; wherein the tip structure comprises two groups of side grooves which are centrally symmetrically arranged with respect to the central axis of the lumen, and the two groups of side grooves are respectively in communication with the two groups of blood passages; the side grooves are sequentially provided with a first flat section, a curved smooth transition section, and a second flat section along the axial direction of the tube body from the opening at the distal end of the tube body; the radial width of the second flat section is smaller than the radial width of the first flat section, and the radial width of the second flat section is less than or equal to 2 mm; the second flat section is tangent to the tube body; the distance between the tangent surfaces on both sides of the second flat section gradually increases from inside to outside along the radial direction of the tube body; the included angle between the tangent surfaces on both sides of the second flat section is 60°-140°; the total length of the first flat section, the curved smooth transition section, and the second flat section is 15 mm-35 mm; one end of the second flat section is provided with a semicircular arc transition; one end of the first flat section and the curved smooth transition section is provided with a circular arc smooth transition; the radial width of the first flat section is greater than or equal to the maximum radial width of the curved smooth transition section; the other end of the second flat section and the curved smooth transition section is provided with a circular arc smooth transition; and the radial width of the second flat section is less than or equal to the minimum radial width of the curved smooth transition section.

[0007] In addition, the hemodialysis catheter according to the present application can also have the following additional technical features:

[0008] Further, the side grooves share a first straight hole edge surface on one side edge thereof along the axial direction of the tube body; and the side grooves are sequentially and smoothly connected by a second straight hole edge surface, a first smooth curved edge surface, and a third straight hole edge surface on the opposite side edge thereof along the axial direction of the tube body.

[0009] Further, the first straight hole edge surface is perpendicular to the second straight hole edge surface, and the curvature radius of the first smooth curved edge surface changes as a single-period sine function along the extension direction thereof.

[0010] Further, the radial section of the tip structure transitions from a circular shape to an elliptical shape along its extending path, wherein the length of the long axis of the elliptical shape is equal to the diameter of the circular shape, and the length of the short axis of the elliptical shape is less than 4 / 5 of the length of the long axis of the elliptical shape.

[0011] Further, the partition plate extends axially along the tube body to outside of the lumen, and the portion of the partition plate located outside of the lumen is provided with a second smooth curved edge surface which is smoothly connected with the edge of the distal opening of the tube body.

[0012] Further, the radial width of the second flat section is 0.5mm-2.0mm.

[0013] Further, the length of the first flat section is 3mm-7mm.

[0014] Further, the length of the second flat section is 3mm-15mm.

[0015] The beneficial effects of the present application at least include: by setting two groups of side grooves which are central symmetric to the central axis of the lumen, and setting a tapered curved smooth transition section between the two flat sections which are staggered in the axial space of the side grooves, the tip structure has no sharp corners and no transition is not smooth, so that the blood flow is more smooth, the turbulence is reduced, the shear stress of blood flow is reduced, thereby reducing the risk of platelet activation and mechanical hemolysis, and finally reducing the probability of thrombosis; at the same time, the included angle between the two flat surfaces on both sides of the second flat section is set to 60°-140°, and the tail end of the second flat section adopts a semicircular arc transition design, which can avoid the impact of blood flow on the catheter side wall, reduce the shear stress of blood, and further reduce the formation of thrombus; at the same time, the first flat section, the curved smooth transition section and the second flat section form a tapered channel structure, which can promote the self-flushing effect of blood on the inner wall of the catheter during catheter sealing, reduce the deposition of blood coagulation factors, reduce the risk of catheter blockage, and at the same time, the backflow port of the second flat section forms an included angle with the central axis of the catheter, which improves the positional blockage caused by catheter adhesion; at the same time, the radial width of the second flat section is strictly controlled within 2mm, which can avoid the problem of high PLI and easy blockage caused by excessive width, and can also avoid the problem of increased recirculation caused by the dispersion of blood flow out of the side wall due to the lack of limiting; in addition, the lateral opening (first flat section) and the lateral opening (second flat section) are designed by an axial distance difference (i.e. not at the same horizontal position), since the arterial end blood flows out from the first flat section (wider inlet), and the venous end blood flows back from the second flat section (narrower outlet), the intersection point of the arterial end blood flow and the venous end blood flow is pushed away from the catheter tip, thereby reducing the direct mixing of the two blood flows, in addition, during the process of blood flow out of the first flat section, the effective cross-sectional area of the flow passage gradually decreases, and the flow velocity gradually increases, which can form a certain jet effect, so that the blood flow can flow deeper into the center of the blood vessel after flowing out of the first flat section, thereby reducing the contact with the venous end backflow, thereby solving the problem of high recirculation rate of the tip structure without side hole. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the first view angle of the hemodialysis catheter in an embodiment of the present application.

[0017] Figure 2 It is a structural schematic diagram of the second view angle of the hemodialysis catheter in an embodiment of the present application.

[0018] Figure 3 It is a structural schematic diagram of the first view angle of the tip structure of the hemodialysis catheter in an embodiment of the present application. Figure 2 It is a local enlarged view of A in the middle.

[0019] Figure 4 It is a structural schematic diagram of the first view angle of the tip structure of the hemodialysis catheter in an embodiment of the present application.

[0020] Figure 5 Structure diagram of a second perspective view of a tip structure of a hemodialysis catheter in an embodiment of the present application;

[0021] Figure 6 Radial sectional view of a tip structure of a hemodialysis catheter in an embodiment of the present application;

[0022] Figure 7 Distribution diagram of a region where the shear stress is greater than 10 Pa of a hemodialysis catheter in Embodiment 1 to Embodiment 5 of the present application in a dialysis state;

[0023] Figure 8 Distribution diagram of the inner side wall surface shear stress of a hemodialysis catheter in Embodiment 1 to Embodiment 5 of the present application in a sealed state;

[0024] Figure 9 Distribution diagram of a region where the shear stress is greater than 10 Pa of a hemodialysis catheter in Embodiment 3, Embodiment 9 to Embodiment 12 of the present application in a dialysis state;

[0025] Figure 10 Distribution diagram of the inner side wall surface shear stress of a hemodialysis catheter in Embodiment 3, Embodiment 9 to Embodiment 12 of the present application in a sealed state;

[0026] Figure 11 Curve diagram of the relationship between PLI and length L formed according to the statistical data of Comparative Example 1, Comparative Example 2, and Embodiment 1 to Embodiment 8 in the present application;

[0027] Figure 12 Curve diagram of the relationship between PLI and width W formed according to the statistical data of Comparative Example 3, Comparative Example 4, Embodiment 3, and Embodiment 9 to Embodiment 15 in the present application;

[0028] Figure 13 10% isosurface diagram of the streamline and the proportion of filtered blood of a hemodialysis catheter in Embodiment 3 of the present application in a dialysis state;

[0029] Figure 14 Streamline and velocity cloud diagram of a hemodialysis catheter in Embodiment 3 of the present application in a dialysis state;

[0030] Figure 15 Distribution diagram of the shear stress of the venous lumen to the venous vessel wall of a hemodialysis catheter in Embodiment 3 of the present application in a dialysis state;

[0031] Figure 16 Distribution diagram of the wall surface shear stress of the lumen of a hemodialysis catheter in Embodiment 3 of the present application in a dialysis state;

[0032] Figure 17Velocity and streamline plot for the hemodialysis catheter in Example 3 of the present invention near the tip in the capped state;

[0033] Figure 18 Volume fraction of heparin and streamline plot for the hemodialysis catheter in Example 3 of the present invention in the lumen in the capped state;

[0034] Figure 19 Wall shear stress distribution plot for the hemodialysis catheter in Example 3 of the present invention in the capped state;

[0035] Figure 20 Front and side view of the hemodialysis catheter with side hole and helical symmetric tip design manufactured by C.R. Bard, Inc. with lot number 2324100142;

[0036] Figure 21 Front and side view of the hemodialysis catheter with side hole and helical symmetric tip design manufactured by C.R. Bard, Inc. with lot number 2314300079;

[0037] Explanation of main component symbols:

[0038] Tube body 100, side groove 110, first straight section 111, curved smooth transition section 120, second straight section 122, first straight hole edge surface 130, second straight hole edge surface 140, first smooth curved edge surface 150, third straight hole edge surface 160, partition plate 200, arterial lumen 210, venous lumen 220, second smooth curved edge surface 230;

[0039] The following detailed description will further describe the present invention with reference to the above mentioned figures. DETAILED DESCRIPTION

[0040] In order to facilitate the understanding of the present invention, the following will make a more comprehensive description of the present invention with reference to the relevant drawings. The drawings show several embodiments of the present invention. However, the present invention can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0041] It should be noted that when an element is referred to as being "fixedly attached" to another element, it can be directly on the other element or there can be an intervening element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements can be present. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. The use herein of the terms "and / or" includes a set of one or more associated listed items.

[0043] Please refer to Figures 1 to 6 A hemodialysis catheter provided by the present application comprises a cylindrical tube body 100 and a partition plate 200. Specifically, the tube body 100 is provided with a lumen along its axial direction, and the lumen can be in a D shape or other shapes. The end of the tube body 100 inserted into the body (i.e. the distal end of the tube body 100) is provided with a tip structure communicating with the lumen, and the partition plate 200 is arranged in the lumen to divide the lumen into two groups of blood passages arranged side by side along the axial direction of the tube body 100, and the two groups of blood passages can be of the same size or different sizes. One group of blood passages serves as an arterial lumen 210, and the other group of blood passages serves as a venous lumen 220. The tip structure comprises two groups of side grooves 110 arranged symmetrically with respect to the center of the central axis of the lumen, and the two groups of side grooves 110 respectively communicate with the two groups of blood passages, so that the hemodialysis catheter can be used in both positive and reverse connection modes. The side groove 110 is sequentially provided with a first flat section 111, a curved smooth transition section 120 and a second flat section 122 along the axial direction of the tube body 100 from the distal end opening. The radial width of the first flat section 111 and the second flat section 122 remains unchanged along the axial direction, the radial width of the curved smooth transition section 120 gradually decreases from the distal end opening of the tube body 100 from outside to inside, so as to form a smooth tapered narrowing between the first flat section 111 and the second flat section 122, the second flat section 122 is tangent to the tube body 100, thereby forming two tangent surfaces (such as Figure 5 the upper tangent surface S1 and the lower tangent surface S2 in the drawing) arranged symmetrically with respect to the central axial surface C1 of the tube body 100 on both sides of the second flat section 122, the distance between the upper tangent surface S1 and the lower tangent surface S2 gradually increases from inside to outside along the radial direction of the tube body 100, the included angle β between the upper tangent surface S1 and the lower tangent surface S2 is arranged to be 60°-140°, the radial width of the second flat section 122 is smaller than the radial width of the first flat section 111, and the radial width of the second flat section 122 is less than or equal to 2mm, and the end of the second flat section 122 away from the curved smooth transition section 120 is arranged in a semicircular arc transition.

[0044] In this embodiment, when the distal end of the tube 100 is inserted into the patient's superior vena cava, negative pressure is applied to the connector at the proximal end of the tube 100, allowing blood circulating in the body to enter through the side groove 110 connected to the arterial lumen 210, pass through the arterial lumen 210 and the connector to the extracorporeal circulation, where the blood is purified by dialysis outside the body. The dialyzed blood is then transferred from the connector to the venous lumen 220, and then returned to the body's internal circulation through the side groove 110 connected to the venous lumen 220, thereby achieving hemodialysis treatment.

[0045] In some alternative embodiments, such as Figure 3 , Figure 4 As shown, the left end of the first straight segment 111 and the smooth transition segment 120 is smoothly transitioned by an arc, and the radial width of the first straight segment 111 is greater than or equal to the maximum radial width of the smooth transition segment 120. In this embodiment, the smooth transition from the first straight segment 111 to the smooth transition segment 120 makes blood flow smoother, reduces turbulence, and lowers the shear stress of blood flow, thereby reducing the probability of thrombus formation. Simultaneously, when the tip structure adheres to the wall, the smooth transition causes less stimulation to the body tissues, thus reducing stress damage to the body tissues.

[0046] In some alternative embodiments, such as Figure 3 , Figure 4 As shown, the second straight segment 122 and the right end of the curved smooth transition segment 120 are smoothly transitioned by an arc, and the radial width of the second straight segment 122 is less than or equal to the minimum radial width of the curved smooth transition segment 120. In this embodiment, the smooth transition from the curved smooth transition segment 120 to the second straight segment 122 makes the blood flow smoother, reduces turbulence, and lowers the shear stress of blood flow, thereby reducing the probability of thrombus formation. At the same time, when the tip structure adheres to the wall, the smooth transition causes less stimulation to the body tissues, thereby reducing stress damage to the body tissues.

[0047] In some alternative embodiments, such as Figure 3 As shown, the side groove 110 shares a first straight hole side surface 130 along the lower side of the tube body 100 along the axial direction. The side groove 110 is smoothly connected from the distal opening of the tube body 100 along the upper side of the tube body 100 along the axial direction through a second straight hole side surface 140, a first smooth curved side surface 150 and a third straight hole side surface 160, so that the edge of the side groove 110 is smoothly transitioned as a whole, thereby improving hemodynamic performance and reducing the probability of thrombus formation.

[0048] In some alternative embodiments, such as Figure 4 , Figure 5As shown, the first straight hole edge surface 130 and the second straight hole edge surface 140 are perpendicular to each other, and the curvature radius of the first smooth curved edge surface 150 varies as a single period sinusoidal function along the extension direction thereof. Preferably, the peak value of the absolute value of the curvature radius is controlled between 2mm and 3mm, for example, the curvature radius of point E is set to 2.45mm, and the curvature radius of point F is set to -2.49mm. In the present embodiment, by arranging the first smooth curved edge surface 150 with sinusoidal variation of the curvature radius between the first straight hole edge surface 130 and the second straight hole edge surface 140 arranged perpendicularly to each other, the wall shear stress of the side groove 110 can be maintained within the ideal range, the area of the low shear zone is reduced, thereby meeting the requirements of hemodynamics, while the pipe wall structure is maintained to the greatest extent, the open area is maintained to be large, and the tensile strength of the catheter tip is improved.

[0049] In some alternative embodiments, as shown in FIG. 6, the first straight hole edge surface 130 and the second straight hole edge surface 140 are arranged perpendicularly to each other, and the curvature radius of the first smooth curved edge surface 150 varies as a single period sinusoidal function along the extension direction thereof. Preferably, the peak value of the absolute value of the curvature radius is controlled between 2mm and 3mm, for example, the curvature radius of point E is set to 2.45mm, and the curvature radius of point F is set to -2.49mm. In the present embodiment, by arranging the first smooth curved edge surface 150 with sinusoidal variation of the curvature radius between the first straight hole edge surface 130 and the second straight hole edge surface 140 arranged perpendicularly to each other, the wall shear stress of the side groove 110 can be maintained within the ideal range, the area of the low shear zone is reduced, thereby meeting the requirements of hemodynamics, while the pipe wall structure is maintained to the greatest extent, the open area is maintained to be large, and the tensile strength of the catheter tip is improved. Figure 6 As shown in FIG. 7, the radial cross section of the tip structure transitions from a circular shape to an elliptical shape along the extension path thereof, specifically, the transverse dimension at the center is unchanged, i.e. the length of the major axis of the elliptical shape is equal to the diameter of the circular shape, and the longitudinal dimension at the center is reduced (as shown in FIG. 7, the dimension H1 in FIG. 6 is reduced to the dimension H2). Preferably, the length of the minor axis of the elliptical shape is less than 4 / 5 of the length of the major axis of the elliptical shape. In the present embodiment, the variable cross section design causes the backflow port of the second straight section 122 to form an angle with the catheter central axis, thereby improving the positional obstruction caused by the catheter wall adhesion. Figure 6 As shown in FIG. 8, the radial cross section of the tip structure transitions from a circular shape to an elliptical shape along the extension path thereof, specifically, the transverse dimension at the center is unchanged, i.e. the length of the major axis of the elliptical shape is equal to the diameter of the circular shape, and the longitudinal dimension at the center is reduced (as shown in FIG. 8, the dimension H1 in FIG. 6 is reduced to the dimension H2). Preferably, the length of the minor axis of the elliptical shape is less than 4 / 5 of the length of the major axis of the elliptical shape. In the present embodiment, the variable cross section design causes the backflow port of the second straight section 122 to form an angle with the catheter central axis, thereby improving the positional obstruction caused by the catheter wall adhesion.

[0050] In some alternative embodiments, as shown in FIG. 9, the partition plate 200 extends to the outside of the lumen along the axial direction of the pipe body 100, and the portion of the partition plate 200 located outside the lumen is provided with a second smooth curved edge surface 230 which is smoothly connected with the edge of the distal end opening of the pipe body 100. In the present embodiment, the partition plate 200 extends to the outside of the lumen and is smoothly connected with the distal end of the pipe body 100 through the second smooth curved edge surface 230, thereby avoiding the sharp part of the tip structure which mechanically stimulates the blood vessel, while ensuring the effective separation of the arterial lumen 210 and the venous lumen 220. Figure 3 In some alternative embodiments, as shown in FIG. 10, the total length L of the first straight section 111, the curved smooth transition section 120 and the second straight section 122 is 15mm-35mm. In the present embodiment, in the case where the side groove 110 is not provided with a side hole, if the total length L is too short, the recirculation rate is high, if the total length L is too long, the area which is not sealed by the pipe is large, and the risk of long thrombus is high, therefore the total length L is set to 15mm-35mm.

[0051] Figure 4 In some alternative embodiments, as shown in FIG. 11, the radial width W of the second straight section 122 is 0.5mm-2.0mm.

[0052] In some alternative embodiments, as shown in FIG. 12, the radial width W of the second straight section 122 is 0.5mm-2.0mm. Figure 4 In some alternative embodiments, as shown in FIG. 13, the radial width W of the second straight section 122 is 0.5mm-2.0mm.​

[0053] In some optional embodiments, the length of the first flat section 111 is 3mm-7mm.

[0054] In some optional embodiments, the length of the second flat section 122 is 3mm-15mm.

[0055] The application is further described below with specific embodiments:

[0056] Embodiment 1

[0057] This embodiment provides a hemodialysis catheter, denoted as dc2-1, comprising a tube body 100 and a partition plate 200. Specifically, the cylindrical tube body 100 is provided with a lumen along its axial direction, and the end of the tube body 100 inserted into the body (i.e. the distal end of the tube body 100) is provided with a tip structure communicating with the lumen, and the partition plate 200 is arranged in the lumen to divide the lumen into two groups of D-shaped blood passages of the same size arranged side by side along the axial direction of the tube body 100, one group of D-shaped blood passages being an arterial lumen 210 and the other group of D-shaped blood passages being a venous lumen 220; wherein the tip structure comprises two groups of side grooves 110 arranged symmetrically with respect to the center of the lumen axis, the two groups of side grooves 110 respectively communicating with the two groups of blood passages, and the side groove 110 is sequentially provided with a first flat section 111, a curved smooth transition section 120 and a second flat section 122 along the axial direction of the tube body 100 from the distal end opening, the outer diameter of the tube body 100 is 3.5mm-5.5mm, the wall thickness of the tube body 100 is 0.4mm-0.7mm, the total length L of the first flat section 111, the curved smooth transition section 120 and the second flat section 122 is 15mm, the length of the first flat section 111 is 3mm-7mm, the length of the second flat section 122 is 3mm-15mm, and the radial width W of the second flat section 122 is 0.83mm.

[0058] Embodiment 2

[0059] This embodiment provides a hemodialysis catheter, denoted as dc2-2, which is different from the hemodialysis catheter provided in Embodiment 1 in that, in this embodiment, the total length L of the first flat section 111, the curved smooth transition section 120 and the second flat section 122 is 18mm.

[0060] Embodiment 3

[0061] This embodiment provides a hemodialysis catheter, denoted as dc2-3, which is different from the hemodialysis catheter provided in Embodiment 1 in that, in this embodiment, the total length L of the first flat section 111, the curved smooth transition section 120 and the second flat section 122 is 21mm.

[0062] Embodiment 4

[0063] The present embodiment provides a hemodialysis catheter, denoted as dc2-4, which is different from the hemodialysis catheter provided in Embodiment 1 in that, in the present embodiment, the total length L of the first straight section 111, the curved smooth transition section 120 and the second straight section 122 is 24 mm.

[0064] Embodiment 5

[0065] The present embodiment provides a hemodialysis catheter, denoted as dc2-5, which is different from the hemodialysis catheter provided in Embodiment 1 in that, in the present embodiment, the total length L of the first straight section 111, the curved smooth transition section 120 and the second straight section 122 is 27 mm.

[0066] Embodiment 6

[0067] The present embodiment provides a hemodialysis catheter, which is different from the hemodialysis catheter provided in Embodiment 1 in that, in the present embodiment, the total length L of the first straight section 111, the curved smooth transition section 120 and the second straight section 122 is 30 mm.

[0068] Embodiment 7

[0069] The present embodiment provides a hemodialysis catheter, which is different from the hemodialysis catheter provided in Embodiment 1 in that, in the present embodiment, the total length L of the first straight section 111, the curved smooth transition section 120 and the second straight section 122 is 33 mm.

[0070] Embodiment 8

[0071] The present embodiment provides a hemodialysis catheter, which is different from the hemodialysis catheter provided in Embodiment 1 in that, in the present embodiment, the total length L of the first straight section 111, the curved smooth transition section 120 and the second straight section 122 is 35 mm.

[0072] Comparative Example 1

[0073] The present embodiment provides a hemodialysis catheter, which is different from the hemodialysis catheter provided in Embodiment 1 in that, in the present embodiment, the total length L of the first straight section 111, the curved smooth transition section 120 and the second straight section 122 is 12 mm.

[0074] Comparative Example 2

[0075] The present embodiment provides a hemodialysis catheter, which is different from the hemodialysis catheter provided in Embodiment 1 in that, in the present embodiment, the total length L of the first straight section 111, the curved smooth transition section 120 and the second straight section 122 is 36 mm.

[0076] Embodiment 9

[0077] This example provides a hemodialysis catheter, designated dc2-6, which differs from the hemodialysis catheter provided in Example 3 in that in this example the radial width W of the second straight section 122 is 0.47 mm.

[0078] Example 10

[0079] This example provides a hemodialysis catheter, designated dc2-7, which differs from the hemodialysis catheter provided in Example 3 in that in this example the radial width W of the second straight section 122 is 0.66 mm.

[0080] Example 11

[0081] This example provides a hemodialysis catheter, designated dc2-9, which differs from the hemodialysis catheter provided in Example 3 in that in this example the radial width W of the second straight section 122 is 0.99 mm.

[0082] Example 12

[0083] This example provides a hemodialysis catheter, designated dc2-10, which differs from the hemodialysis catheter provided in Example 3 in that in this example the radial width W of the second straight section 122 is 1.15 mm.

[0084] Example 13

[0085] This example provides a hemodialysis catheter, which differs from the hemodialysis catheter provided in Example 3 in that in this example the radial width W of the second straight section 122 is 1.50 mm.

[0086] Example 14

[0087] This example provides a hemodialysis catheter, which differs from the hemodialysis catheter provided in Example 3 in that in this example the radial width W of the second straight section 122 is 1.80 mm.

[0088] Example 15

[0089] This example provides a hemodialysis catheter, which differs from the hemodialysis catheter provided in Example 3 in that in this example the radial width W of the second straight section 122 is 2.0 mm.

[0090] Comparative Example 3

[0091] This example provides a hemodialysis catheter, which differs from the hemodialysis catheter provided in Example 3 in that in this example the radial width W of the second straight section 122 is 0.32 mm.

[0092] Comparative Example 4

[0093] The embodiment provides a hemodialysis catheter, and the radial width W of the second straight section 122 is 2.2 mm in the embodiment.

[0094] Embodiment 16

[0095] The embodiment provides a hemodialysis catheter, which comprises a tube body 100 and a partition plate 200. Specifically, the tube body 100 is provided with a lumen along the axial direction thereof, one end (i.e. the distal end of the tube body 100) of the tube body 100 is provided with a tip structure communicating with the lumen, and the partition plate 200 is arranged in the lumen to divide the lumen into two groups of D-shaped blood passages with the same size arranged side by side along the axial direction of the tube body 100, wherein one group of the D-shaped blood passages is an arterial cavity 210, and the other group of the D-shaped blood passages is a venous cavity 220. The tip structure comprises two groups of side grooves 110 which are centrally symmetrically arranged relative to the central axis of the lumen, the two groups of side grooves 110 respectively communicate with the two groups of blood passages, the side groove 110 is sequentially provided with a first straight section 111, a curved smooth transition section 120 and a second straight section 122 along the axial direction of the tube body 100 from the distal end opening, the outer diameter of the tube body 100 is 3.5mm-5.5mm, the wall thickness of the tube body 100 is 0.4mm-0.7mm, the total length L of the first straight section 111, the curved smooth transition section 120 and the second straight section 122 is 21mm, the length of the first straight section 111 is 3mm-7mm, the length of the second straight section 122 is 3mm-15mm, the radial width W of the second straight section 122 is 0.83mm, and the included angle β between the upper tangent plane S1 and the lower tangent plane S2 is 60°.

[0096] Embodiment 17

[0097] The embodiment provides a hemodialysis catheter, and the included angle β between the upper tangent plane S1 and the lower tangent plane S2 is 100° in the embodiment.

[0098] Embodiment 18

[0099] The embodiment provides a hemodialysis catheter, and the included angle β between the upper tangent plane S1 and the lower tangent plane S2 is 140° in the embodiment.

[0100] Comparative Example 5

[0101] The embodiment provides a hemodialysis catheter, and the included angle β between the upper tangent plane S1 and the lower tangent plane S2 is 40° in the embodiment.

[0102] Comparative Example 6

[0103] The embodiment provides a hemodialysis catheter, wherein the angle β between the upper flat surface S1 and the lower flat surface S2 is 160°.

[0104] Embodiment 19

[0105] The embodiment provides a hemodialysis catheter, which comprises a tube body 100 and a partition plate 200. Specifically, the tube body 100 is provided with a lumen along the axial direction thereof, one end (i.e., the distal end of the tube body 100) of the tube body 100 is provided with a tip structure communicating with the lumen, and the partition plate 200 is arranged in the lumen to divide the lumen into two groups of D-shaped blood passages with the same size arranged side by side along the axial direction of the tube body 100, wherein one group of the D-shaped blood passages is an arterial cavity 210, and the other group of the D-shaped blood passages is a venous cavity 220. The tip structure comprises two groups of side grooves 110 which are centrally symmetrically arranged relative to the central axis of the lumen, the two groups of side grooves 110 respectively communicate with the two groups of blood passages, the side groove 110 is sequentially provided with a first flat section 111, a curved smooth transition section 120 and a second flat section 122 along the axial direction of the tube body 100 from the distal end opening, the outer diameter of the tube body 100 is 3.5mm-5.5mm, the wall thickness of the tube body 100 is 0.4mm-0.7mm, the total length L of the first flat section 111, the curved smooth transition section 120 and the second flat section 122 is 24mm, the length of the first flat section 111 is 3mm-7mm, the length of the second flat section 122 is 3mm-15mm, the radial width W of the second flat section 122 is 1mm, and the angle β between the upper flat surface S1 and the lower flat surface S2 is 100°.

[0106] In the field, the numerical simulation method based on computational fluid dynamics can accurately obtain the flow field in the process of using the hemodialysis catheter, and the performance of different dialysis catheters can be evaluated by analyzing the shear stress, wall shear stress, blood residence time, platelet lysis index, platelet activation index and recirculation rate, so as to guide or optimize the design of the catheter tip and side hole. Among them, the shear stress, and the low flow rate area related to the blood residence time are the key factors for blood clot formation. The core of the catheter tip design is to reduce the shear stress when flowing in, and the shear stress greater than 10Pa is the potential threshold of platelet activation and blood injury, so the volume fraction of the shear stress greater than 10Pa near the catheter tip is one of the key indicators for evaluating the performance of the catheter.

[0107] In addition, the blood residence time is obtained by solving the following equation:

[0108]

[0109] where u, v, w are the three velocity components, t is the scalar residence time, and x, y, z are the spatial coordinates. The boundary conditions for this equation are: at the inlet boundary, the value of the residence time t is given as zero; at the other boundaries, the flux is set to zero. In short, the value of the residence time t at any point represents the time it takes for the fluid to travel from the inlet to that point.

[0110] Dialysis catheter designs generally emphasize higher flow rates, as higher flow rates can theoretically shorten treatment time and reduce the low flow rate zone at the catheter tip. At the same time, excessively high blood flow rates can generate high shear rates, which can lead to platelet activation and mechanical hemolysis, while excessively low flow rates can increase the residence time of blood cells within the lumen, promoting thrombus formation. Therefore, the optimal dialysis catheter flow rate requires a balance, and shear stress and blood residence time need to be considered together.

[0111] The platelet lysis index (PLI) takes into account both shear stress and time, and can comprehensively evaluate the formation of blood clots, and its calculation formula is as follows:

[0112]

[0113] where represents the time exposed to shear stress . It can be seen that the longer the platelets are exposed to high shear stress, the more likely they are to be damaged and form thrombi. Generally, when the PLI is greater than 0.25, the hemodynamic performance of the hemodialysis catheter is poor, when the PLI is in the range of 0.2-0.25, the hemodynamic performance of the catheter is good, and when the PLI is less than 0.2, the hemodynamic performance of the hemodialysis catheter is better.

[0114] Another key parameter of dialysis catheter performance is recirculation rate, which indicates that the dialyzed venous blood does not return well to the body, but is re-pumped back to the dialysis machine for re-dialysis. During dialysis, a minimum proportion of clean blood is required to return to the dialyzer, as higher recirculation rates can require longer hemodialysis times to remove target solutes or control blood pressure. At the same time, high recirculation rates can prolong dialysis time, waste drug resources, make patients bear more economic costs, and increase the risk of complications.

[0115] The hemodynamic performance of the hemodialysis catheters provided in Examples 1 to 8, as well as Comparative Examples 1 and 2, was analyzed using simulation software. It should be noted that the geometry of all hemodialysis catheters was created using the fusion engineering software Solidworks and exported to the mesh generation software Fluent. The final results show the average velocity, average shear stress, volume with shear stress greater than 10 Pa, and platelet-to-liquidity index (PLI) of the fluid in the lumen of each embodiment during dialysis (the process of connecting the hemodialysis catheter to the extracorporeal circulation system for blood purification), and the average flushing velocity and average inner wall shear stress of the fluid in the lumen of each embodiment during the closed state (the stage after dialysis when the lumen of the hemodialysis catheter is closed to prevent thrombosis and infection, such as when heparin is used). Specific data are shown in Table 1.

[0116] Table 1

[0117]

[0118] refer to Figure 7 The distribution of areas with shear stress greater than 10 Pa in the hemodialysis catheters of Examples 1 to 5 under dialysis conditions is shown. Figure 8 The distribution of shear stress on the inner wall of the hemodialysis catheters in Examples 1 to 5 under the sealed state is shown. Combined with the data in Table 1, it can be seen that: as the length L increases, the average blood flow velocity near the tip structure of the hemodialysis catheter first decreases and then increases during dialysis; the average shear stress first decreases and then increases; the volume with shear stress greater than 10 Pa also first decreases and then increases; and the PLI (particulate intensity) also first decreases and then increases. However, in the sealed state, the average scouring velocity of the hemodialysis catheter gradually decreases, and the amplitude continuously narrows; the average shear stress on the inner wall has a maximum value, showing a trend of first increasing and then decreasing. Especially when the length L is selected in the range of 20 mm to 30 mm, the PLI value is less than 0.2, indicating that the hemodynamic performance of the hemodialysis catheter is better at this time.

[0119] The hemodynamic performance of the hemodialysis catheters provided in Examples 3, 9 to 15, and Comparative Examples 3 and 4 was analyzed using simulation software. It should be noted that the geometry of all hemodialysis catheters was created using the fusion engineering software Solidworks and exported to the mesh generation software Fluent Meshing. The final results show the average velocity, average shear stress, volume with shear stress greater than 10 Pa, and platelet-dissolving index of the fluid in the lumen of each embodiment during dialysis, as well as the average flushing velocity and average inner wall shear stress of the fluid in the lumen of each embodiment during the sealed state. Specific data are shown in Table 2.

[0120] Table 2

[0121]

[0122] refer to Figure 9 The distribution of areas with shear stress greater than 10 Pa in the hemodialysis catheters of Examples 3, 9 to 12 under dialysis conditions is shown. Figure 10 The distribution of shear stress on the inner wall of the hemodialysis catheters in Examples 3, 9 to 12 under sealed conditions, as shown in Table 2, indicates that: with the increase of width W, the average blood flow velocity near the tip structure of the hemodialysis catheter gradually decreases, the average shear stress gradually decreases, and the volume with shear stress greater than 10 Pa gradually decreases, but PLI first decreases and then increases; while in the sealed state, the average flushing velocity of the hemodialysis catheter generally shows a gradually increasing trend, and the average shear stress on the inner wall generally shows a gradually increasing trend. Considering all performance indicators, a width W preferably within the range of 0.8 mm to 1.7 mm is preferred.

[0123] It should also be noted that when the width W is less than 0.32, the side groove 110 is very difficult to machine.

[0124] Furthermore, based on all the data provided in Tables 1 and 2, curve fitting was performed on the relationship between the PLI values ​​and the length L and width W, resulting in the following: Figure 11 The relationship between PLI and length L shown, and as... Figure 12 The relationship between PLI and width W is shown. (Comparison) Figure 11 and Figure 12 It can be seen that PLI changes more drastically with length L, indicating that length L has a greater impact on PLI.

[0125] Simultaneously, a simulation analysis of the hemodialysis state was performed on the hemodialysis catheter provided in Example 3, and the results were as follows: Figure 13 The streamlines and filtered blood percentages shown are isosurfaces representing the 10% saturation (where the inlet velocity of the superior vena cava is 0.069 m / s at the simulation time, and the inlet velocity of the dialysis catheter is constant at 1.11 m / s), and as shown... Figure 14 The streamlines and velocity contour plots shown, and Figure 15 The shear stress exerted by the hemodialysis catheter on the venous wall is shown, and Figure 16 The wall shear stress of the hemodialysis catheter lumen is shown.

[0126] Depend on Figure 13It can be seen that the dialysis blood flowing into the hemodialysis catheter in Example 3 is concentrated on one side of the venous lumen 220, and the equivalent surface of the catheter filtering blood is more concentrated, and the aspiration of the arterial lumen 210 mainly occurs at the tail end of the side groove 110, so that recirculation does not occur, and because there is no side hole, the lateral velocity of the outflowing blood is small, so the scouring effect on the blood vessel wall is small.

[0127] It can be seen that the velocity of the blood flowing into the hemodialysis catheter in Example 3 is concentrated on one side of the venous lumen 220, and the equivalent surface of the catheter filtering blood is more concentrated, and the aspiration of the arterial lumen 210 mainly occurs at the tail end of the side groove 110, so that recirculation does not occur, and because there is no side hole, the lateral velocity of the outflowing blood is small, so the scouring effect on the blood vessel wall is small. Figure 14 It can be seen that the velocity of the blood flowing into the hemodialysis catheter in Example 3 is concentrated on one side of the venous lumen 220, and the equivalent surface of the catheter filtering blood is more concentrated, and the aspiration of the arterial lumen 210 mainly occurs at the tail end of the side groove 110, so that recirculation does not occur, and because there is no side hole, the lateral velocity of the outflowing blood is small, so the scouring effect on the blood vessel wall is small.

[0128] Figure 15 It can be seen that the wall shear stress of the blood vessel wall near the outlet of the venous lumen 220 of the hemodialysis catheter in Example 3 is small (when the wall shear stress of the blood vessel wall is greater than 10 Pa, it will have a strong stimulation on the blood vessel), and only the tail end of the side groove 110 of the venous lumen 220 has a large wall shear stress. Figure 16 It should be noted that the streamlines described above are curves that describe the trajectory of fluid motion. For blood flow, streamlines can intuitively show the direction and path of blood flow in the hemodialysis catheter and blood vessel, and velocity cloud maps can intuitively show the distribution of blood flow rate in the hemodialysis catheter and blood vessel. In blood flow data processing, some filtering algorithms are usually used to remove noise or highlight specific blood flow characteristics. The 10% blood volume fraction isophase after filtering is that in the filtered blood flow data, the area with a blood volume fraction of 10% is extracted and visualized. This isophase can be used as a reference to help analyze and understand the distribution of blood in the hemodialysis catheter and blood vessel under specific blood flow conditions. Combining streamlines and the 10% blood volume fraction isophase can more comprehensively analyze the characteristics and rules of blood flow. Streamlines provide direction and path information of blood flow, and the 10% isophase provides distribution and proportion information of blood flow in space. The two complement each other.

[0129] Further, the hemodialysis catheter provided in Example 3 was simulated and analyzed in a sealed state, and the velocity and streamline diagram near the catheter tip is shown in

[0130] , the heparin volume fraction and streamline diagram is shown in Figure 17 , and the wall shear stress distribution diagram on the inside of the catheter lumen is shown in Figure 18 Figure 19 It can be seen that the velocity of the blood flowing into the hemodialysis catheter in Example 3 is concentrated on one side of the venous lumen 220, and the equivalent surface of the catheter filtering blood is more concentrated, and the aspiration of the arterial lumen 210 mainly occurs at the tail end of the side groove 110, so that recirculation does not occur, and because there is no side hole, the lateral velocity of the outflowing blood is small, so the scouring effect on the blood vessel wall is small. Figure 17 ​​It can be seen that the side groove 110 of the hemodialysis catheter in Example 3 can also successfully guide the blood flow into the catheter, and the statistical data of the average flushing speed is 0.046 m / s, thereby forming the effect of strong flushing of the lumen of the tip end. It can be seen from Figure 18 It can be seen that there is a certain heparin adhesion on the local wall surface of the catheter tip, which is due to the wall adhesion. This indicates that the end of the dialysis catheter will cause blood adhesion due to the effect of wall adhesion, and form blood clotting over time, so the design of the dialysis catheter must consider introducing blood flow and forming wall shear stress to flush the wall to prevent blood clotting. In combination with Figure 19 It can be seen that, Figure 18 the blood adhesion area shown in Figure 19 and the range with small wall shear stress value in It can be seen that the average wall shear stress of the hemodialysis catheter in Example 3 is larger, and the statistical data of the average wall shear stress is 0.577 Pa, so that the wall can be flushed with a larger force, thereby playing a function of preventing blood clotting.

[0131] Further, the hemodialysis catheters provided by Examples 16 to 18, and Comparative Examples 5 and 6 are analyzed for hemodynamic performance using simulation software. It should be noted that the geometric figures of all the hemodialysis catheters are created using the fusion engineering software Solidworks and exported to the mesh division software Fluent. Finally, the average velocity of the fluid in the lumen of the hemodialysis catheter of each example, the average shear stress, the volume of shear stress greater than 10 Pa, and the platelet lysis index PLI when the hemodialysis catheter is in a dialysis state (the hemodialysis catheter is connected to an extracorporeal circulation system for blood purification) are obtained, and the specific data are shown in Table 3:

[0132] Table 3

[0133]

[0134] According to the data in Table 3, it can be seen that as the angle β increases, the average blood flow velocity near the tip structure of the hemodialysis catheter in the dialysis state gradually decreases, the average shear stress gradually decreases and the amplitude continuously decreases, the volume of shear stress greater than 10 Pa also gradually decreases and the amplitude continuously decreases, but the PLI first decreases and then increases. In combination with various performance indicators, the angle β is preferably selected from the range of 60° to 140°.

[0135] Further, the hemodialysis catheter of Example 19 and the existing spiral symmetric tip design are tested in vitro for the data of recirculation rate. The existing spiral symmetric tip design of the blood catheter selects two groups, one group is selected from the spiral symmetric tip design of the hemodialysis catheter with a side hole produced by the Coeur Limited Liability Company with a batch number of 2324100142, and the specific structure of the front and side surfaces is shown inFigure 20 , another group is selected from the blood dialysis catheter with side hole and spiral symmetrical tip design produced by C.R. Bard, Inc. with batch number 2314300079, the specific structure of the front and side of which is shown in Figure 21 Test conditions: blood flow rate is set to 2000 mL / min, and the flow rate of the simulated dialysis pipeline (venous end, arterial end) is set to 300 mL / min. Test scheme: after each fluid passage runs stably for 2 minutes, a detection liquid sample is taken every 1 min, and ultraviolet analysis is performed thereon. The final experimental database is shown in Table 4:

[0136] Table 4

[0137]

[0138] According to the data in Table 4, it can be seen that, compared with the blood dialysis catheter with side hole and spiral symmetrical tip design with batch number 2324100142, the recirculation rate of Example 19 is reduced after the side hole is cancelled, and compared with the blood dialysis catheter with side hole and spiral symmetrical tip design with batch number 2314300079, the recirculation rate of Example 19 can achieve the same effect after the side hole is cancelled, and the problem of contradiction between recirculation rate and thrombus setting value is solved.

[0139] In summary, through the setting of the central symmetrical tapered side groove structure (containing the specifically designed curved surface smooth transition section and smooth transition edge surface) at the distal end of the tube body and the accurate size control, the shear stress of the catheter tip area is effectively reduced, hemolysis and thrombus formation are significantly inhibited, and at the same time, the optimized symmetrical design significantly reduces the blood recirculation rate during reverse connection operation, overcomes the defects of the prior art, achieves the overall structure combined with the optimized fluid dynamics performance and reliable size parameters, improves the efficiency and safety of hemodialysis treatment, and guarantees the long-term indwelling reliability and manufacturing feasibility of the catheter.

[0140] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0141] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the protection scope of the present application. It should be pointed out that for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, which all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A hemodialysis catheter, characterized in that, The hemodialysis catheter comprises: a cylindrical tube body, an inner cavity of which is provided with blood passages along an axial direction of the tube body, and a tip structure is provided at a distal end of the tube body and communicates with the inner cavity; a partition plate is provided in the inner cavity to divide the inner cavity into two groups of blood passages arranged side by side along the axial direction of the tube body; wherein the tip structure comprises two groups of side grooves which are centrally symmetrically arranged relative to a central axis of the inner cavity, the two groups of side grooves respectively communicate with the two groups of blood passages, and the side grooves are sequentially provided with a first flat section, a curved smooth transition section and a second flat section along the axial direction of the tube body from an opening at the distal end of the tube body, the radial width of the second flat section is smaller than the radial width of the first flat section, and the radial width of the second flat section is less than or equal to 2 mm, the second flat section is tangent to the tube body, the distance between the tangent surfaces on both sides of the second flat section gradually increases from inside to outside along the radial direction of the tube body, the included angle between the tangent surfaces on both sides of the second flat section is 60°-140°, the total length of the first flat section, the curved smooth transition section and the second flat section is 15 mm-35 mm, and one end of the second flat section is provided with a semicircular arc transition. The first flat section and one end of the curved smooth transition section are smoothly connected by an arc, and the radial width of the first flat section is greater than or equal to the maximum radial width of the curved smooth transition section. The second flat section and the other end of the curved smooth transition section are smoothly connected by an arc, and the radial width of the second flat section is less than or equal to the minimum radial width of the curved smooth transition section.

2. The hemodialysis catheter of claim 1, wherein, The side grooves share a first straight hole edge surface on one side along the axial direction of the tube body, and the side grooves are smoothly connected by a second straight hole edge surface, a first smooth curved edge surface and a third straight hole edge surface in sequence on the other side opposite to the one side along the axial direction of the tube body from the opening at the distal end of the tube body.

3. The hemodialysis catheter of claim 2, wherein, The first straight hole edge surface is perpendicular to the second straight hole edge surface, and the curvature radius of the first smooth curved edge surface changes as a single-period sine function along the extension direction thereof.

4. The hemodialysis catheter of claim 1, wherein, The radial cross section of the tip structure is transitioned from a circular shape to an elliptical shape along the extension path thereof, wherein the length of the major axis of the elliptical shape is equal to the diameter of the circular shape, and the length of the minor axis of the elliptical shape is less than 4 / 5 of the length of the major axis of the elliptical shape.

5. The hemodialysis catheter of claim 1, wherein, The partition plate extends to the outside of the inner cavity along the axial direction of the tube body, and the portion of the partition plate located outside the inner cavity is provided with a second smooth curved edge surface which is smoothly connected with the opening edge of the distal end of the tube body.

6. The hemodialysis catheter of any one of claims 1-5, wherein, The radial width of the second flat section is 0.5 mm-2.0 mm.

7. The hemodialysis catheter of claim 6, wherein, The length of the first flat section is 3 mm-7 mm.

8. The hemodialysis catheter of claim 7, wherein, The length of the second flat section is 3 mm-15 mm.

Images