A high axial support dilating catheter

Abstract

The application provides a high-axial-support expansion catheter, relates to the technical field of medical devices, and comprises a luer joint; an expansion tube section connected with the luer joint; the expansion tube section comprises a first tube section, a second tube section and a third tube section arranged in sequence in the direction away from the luer joint; the second tube section comprises an inner layer and an outer layer wrapped outside the inner layer; the outer layer is provided with an elastomer, and the hardness of the elastomer is lower than the hardness of the inner layer, the first tube section and the third tube section. When the expansion catheter is used in cooperation with an outer sheath with a complex bending shape, the corresponding bending position of the expansion catheter has high axial strength and sufficient flexibility, so that the expansion catheter can smoothly pass through skin tissue or an atrial septum and the like, the influence of the angle change of the outer sheath is small when the outer sheath is withdrawn, and the sheath can be ensured to be left in a predetermined position.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and in particular to a dilation catheter with high axial support. Background Technology

[0002] When establishing intraoperative access in interventional vascular procedures, the design of the sheath assembly (sheath and dilator) should be adjusted according to conditions such as the location of the lesion or the responsible vessel. Therefore, for some complex and tortuous vascular pathways, the instruments need to be designed with complex bends. For example, in left atrial appendage occlusion, the sheath needs to enter the left atrial appendage via the inferior vena cava-right atrium-atrial septum-left atrium-left atrial appendage. Therefore, depending on the specific location of the left atrial appendage, the sheath needs to be designed with a bend in two spatial dimensions. In thrombectomy, the sheath needs to enter the pulmonary artery via the inferior vena cava-right atrium-right ventricle-pulmonary artery pathway to complete the thrombectomy.

[0003] In actual clinical surgery, the dilator catheter is first inserted into the sheath, and a guidewire guides the sheath assembly to the lesion site. Then, the dilator catheter is withdrawn from the sheath, leaving only the sheath inside the body to create a passage. During this process, due to the high rigidity of the dilator catheter, the sheath may deform and its angle may shift when withdrawn from the complexly curved sheath. If the angle change is too large, the sheath may displace from its intended position, requiring the surgeon to reposition it, thus prolonging the operation time and increasing the surgical risk. The larger the sheath size (12F and above) and the greater the bending angle, the more severe these problems become.

[0004] The issue of sheath angle variation can be addressed by designing the dilator catheter as a low-rigidity catheter, as lower catheter rigidity minimizes its impact on the angle variation when passing through sheaths with complex angles. However, this introduces other problems: when the sheath and dilator catheter pass through areas such as skin tissue or the interatrial septum, the dilator catheter requires a certain level of axial support. Otherwise, insufficient axial support can cause the dilator catheter to retract axially as it passes through tissue, creating a step with the sheath, which not only causes pain for the patient but may also lead to safety issues. Therefore, there is an urgent need to develop a dilator catheter that combines high axial support with a flexible bend. Utility Model Content

[0005] This application provides a dilation catheter with high axial support to solve the problem that existing dilation catheters cannot simultaneously provide axial support and prevent sheath displacement.

[0006] This application provides a high axial support dilation catheter, comprising:

[0007] Luer joint;

[0008] The expansion tube section connected to the Luer joint;

[0009] The expansion pipe section includes a first pipe section, a second pipe section, and a third pipe section arranged sequentially in a direction away from the Luer joint;

[0010] The second pipe section includes an inner layer and an outer layer covering the outside of the inner layer;

[0011] The outer layer is provided with an elastomer, and the hardness of the elastomer is lower than that of the inner layer, the first pipe section and the third pipe section.

[0012] In some embodiments, the outer layer includes a support rod; the support rod is arranged along an axis parallel to the second pipe segment, and its two ends are respectively connected to the first pipe segment and the third pipe segment; one side of the support rod is connected to the inner layer.

[0013] In some embodiments, the support rod includes an axial portion and at least one branch portion; the two ends of the axial portion are respectively connected to the first pipe segment and the third pipe segment; one end of the branch portion is connected to the axial portion, and the other end extends circumferentially along the second pipe segment.

[0014] In some embodiments, multiple support rods are provided, and an elastic body is provided between two adjacent support rods; the elastic bodies are evenly arranged along the circumference of the second pipe segment.

[0015] In some embodiments, the support rod and the inner layer are integrally formed.

[0016] In some embodiments, the support rod and the inner layer are connected by adhesive or welding.

[0017] In some embodiments, the number of support rods is 3 to 8.

[0018] In some embodiments, the first pipe segment, the inner layer, and the third pipe segment are respectively one of PE pipe, PP pipe, PI pipe, PEEK pipe, PTFE pipe, and PVDF pipe.

[0019] In some embodiments, the elastomer is one or more of polyolefin elastomers, polyurethane elastomers, polyamide elastomers, silicone or rubber.

[0020] In some embodiments, the third pipe segment has a tapered tip at the end away from the Luer connector.

[0021] The beneficial effects of the solution provided in this application are: when used in conjunction with an outer sheath with a complex bend, the dilator catheter has high axial strength at the bend position, allowing it to pass smoothly through skin tissue or interatrial septum during use, while also having sufficient flexibility to ensure that the angle change of the outer sheath has little impact when it is withdrawn, thus ensuring that the sheath remains in the predetermined position. Attached Figure Description

[0022] Figure 1 A schematic diagram of the structure of the expansion catheter with high axial support provided in the embodiments of this application;

[0023] Figure 2 A partial schematic diagram of the second segment of the high axial support expansion conduit provided in an embodiment of this application;

[0024] Figure 3 A cross-sectional view of the second segment in the high axial support expansion conduit provided in an embodiment of this application;

[0025] Figure 4 A partial schematic diagram of the support rod in the expansion conduit with high axial support provided in an embodiment of this application. Detailed Implementation

[0026] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of this application.

[0027] See Figure 1 This is a schematic diagram of the structure of the expansion catheter with high axial support provided in the embodiments of this application.

[0028] Depend on Figure 1 It is understood that this application provides a dilation catheter with high axial support, comprising:

[0029] Luer connector 1; The Luer connector is a standard medical device interface. Its core function is to achieve a quick and sealed connection with syringes or infusion devices, ensuring a stable delivery of media such as contrast agents or saline during surgery. This design is directly related to the ease of operation and fluid control reliability of the catheter system.

[0030] The expansion tube section 2 is connected to the Luer connector 1; as the main functional part, its multi-layer segmented structure can ensure that it meets the high axial support requirements when passing through human tissue, and also maintains flexibility in the bending path to maintain the stability of the sheath position. The segmented design makes the catheter form a gradient transition in mechanical properties.

[0031] The expansion tube section 2 includes a first tube section 21, a second tube section 22, and a third tube section 23 arranged sequentially in a direction away from the Luer joint 1. The first tube section 21 serves as a proximal rigid section and mainly undertakes the function of transmitting pushing force. The tapered tip of the third tube section 23 is designed for tissue penetration and passage establishment. The second tube section 22, located in the middle, serves as the core tube section and is mainly used to cooperate with the sheath tube, achieving both axial support and radial compliance through a special structure.

[0032] In some examples, the first tube segment 21 and the third tube segment 23 can be made of a blend of low-density polyethylene (LDPE) and barium sulfate. LDPE provides excellent flexibility (elongation at break > 300%) and low-temperature processability (melt index 2-20 g / 10 min), ensuring the compliance of the catheter when passing through curved blood vessels. After being surface-treated with a silane coupling agent, the barium sulfate particles form a strong interfacial bond with the LDPE matrix. While maintaining a Shore hardness of 45D-55D, the tensile strength can reach 15-25 MPa, which is much higher than that of pure LDPE (about 10 MPa).

[0033] In some examples, the first pipe segment 21 can be a single-layer pipe.

[0034] In some embodiments, the design length of the second tube segment 22 can be determined based on the length of the bent portion of the sheath. For example, if the length of the bent portion of the sheath is 10±5cm, then the length range of the second tube segment of the dilation catheter can also be designed to be 10±5cm.

[0035] See Figure 2 This is a partial schematic diagram of the second segment of the high axial support expansion conduit provided in an embodiment of this application; it should be noted that... Figure 2 This is an attached diagram showing the structural relationship between the inner layer 221 and the outer layer 222, with the elastic element hidden.

[0036] Depend on Figure 2 It is understood that the second tube segment 22 includes an inner layer 221 and an outer layer 222 covering the outside of the inner layer 221; the inner layer 221 serves as a strength layer, and its core function is to provide basic compressive strength and prevent the conduit from collapsing when passing through dense tissue. The composite structure of the outer layer 222 is used to solve the flexibility problem by combining rigid support units with elastic materials to achieve adaptive deformation in bending paths.

[0037] In some examples, the inner 221 material can be a blend of high-density polyethylene (HDPE) and barium sulfate, which has a higher hardness than the first pipe section.

[0038] See Figure 3 This is a cross-sectional view of the second segment in the high axial support expansion conduit provided in the embodiments of this application;

[0039] The outer layer 222 is provided with an elastomer 2221, the hardness of which is lower than that of the inner layer 221, the first tube segment 21, and the third tube segment 23. In this embodiment, a hardness difference is set between different tube segments. The lower hardness of the elastomer 2221 allows the catheter to conform to the shape of the sheath when bent, significantly reducing interference with the sheath angle when the catheter is withdrawn. At the same time, the elastomer 2221 also serves to buffer stress, avoiding local stress concentration caused by direct contact between the support rod and human tissue.

[0040] Furthermore, the outer layer 222 includes support rods 2222; the core function of the support rods 2222 is to establish a mechanical bridge across the tube segments, and their axial layout is directly related to the transmission efficiency of axial support force. This design ensures that pressure can be transmitted from the third tube segment (puncture end) to the proximal end without loss, avoiding energy loss during the pushing process.

[0041] In some examples, the material of the support rod 2222 can be the same as that of the inner layer 221.

[0042] In some examples, the material hardness of the support rod 2222 and the inner layer 221 can be 5D to 15D higher than the Shore hardness of the first pipe section 21.

[0043] The support rod 2222 is arranged parallel to the axis of the second pipe segment 22, and its two ends are connected to the first pipe segment 21 and the third pipe segment 23, respectively. The end of the support rod 2222 is connected to the two pipe segments before and after it, which can maintain the continuity of force transmission between segments and avoid the risk of stress concentration fracture caused by sudden changes in hardness. Especially when the catheter passes through tough tissues such as the interatrial septum, this structure can prevent compression deformation of the intermediate segment.

[0044] One side of the support rod 2222 is connected to the inner layer 221. The lateral connection between the support rod 2222 and the inner layer 221 ensures structural stability and provides a basic framework for the coverage of the elastic body 2221 of the outer layer 222.

[0045] See Figure 4 This is a partial schematic diagram of the support rod in the expansion conduit with high axial support provided in the embodiments of this application;

[0046] Furthermore, by Figure 4 It is known that the support rod 2222 includes an axial portion 22221 and at least one branch portion 22222; wherein, the axial portion 22221 undertakes the main axial load transmission function, while the core function of the branch portion 22222 is to further enhance the structural strength between the support rod 2222 and the elastic body 2221.

[0047] During use, when the dilator catheter is inserted into the sheath, the elastic body 2221 of the second tube segment 22 has a certain degree of flexibility, so the angle change at the distal end of the sheath is small after the dilator catheter is inserted into place. The magnitude of the angle change at the distal end of the sheath can be controlled by controlling the number and thickness of the support rods 2222.

[0048] The two ends of the axial section 22221 are connected to the first pipe segment 21 and the third pipe segment 23 respectively; this cross-segment connection forms a mechanically continuous structure, further increasing the axial support effect.

[0049] One end of the branch 22222 is connected to the axis 22221, and the other end extends circumferentially along the second pipe segment 22. The circumferential extension of the branch achieves a spatial anchoring function: it limits excessive displacement of the elastomer during bending and improves bending resistance by dispersing stress. This design allows the conduit to maintain the integrity of its cross-sectional shape when passing through sharp bends.

[0050] Furthermore, multiple support rods 2222 are provided, and an elastic body 2221 is provided between two adjacent support rods 2222. The discrete layout of the support rods 2222 and the spaced filling of the elastic bodies 2221 form a modular structure that combines rigidity and flexibility. Each support rod-elastic body unit functions independently, and together they construct a predictable bending mechanical response, forming the core mechanism for controlling the sheath angle deviation.

[0051] The elastomer 2221 is uniformly arranged circumferentially along the second tube segment 22. This uniform distribution ensures consistent compliance of the catheter in all bending directions. This isotropic design is particularly important for sheaths with complex spatial curvatures (such as double-curved sheaths in left atrial appendage occlusion), as it avoids stress concentration on one side of the sheath due to directional differences.

[0052] Furthermore, the support rod 2222 and the inner layer 221 are integrally formed. This integral forming process eliminates weaknesses in the interface connection, significantly improving fatigue life. This is crucial for interventional devices that repeatedly traverse bending paths, preventing sudden structural failures caused by material delamination.

[0053] In some examples, the support rod 2222 and the inner layer 221 can also be connected by adhesive bonding or welding. This choice of connection method provides process flexibility. Adhesive bonding is more suitable for temperature-sensitive materials, maintaining the integrity of the molecular structure; welding provides higher bond strength, especially suitable for high-load applications.

[0054] In some examples, the elastomer 2221 in the second pipe section 22 can be connected to the support rod 2222 and the inner layer 221 by means of injection, reflow welding, etc.

[0055] Furthermore, the number of support rods 2222 is between 3 and 8. This range directly relates to performance balance: fewer support rods improve flexibility but reduce support strength, while more support rods enhance compressive strength but increase rigidity. This range has been experimentally validated to cover diverse clinical needs, from peripheral vascular to cardiac interventions.

[0056] Furthermore, the first pipe segment 21, the inner layer 221, and the third pipe segment 23 are selected from PE pipe, PP pipe, PI pipe, PEEK pipe, PTFE pipe, and PVDF pipe, respectively. The material selection considers both biocompatibility and the gradient of mechanical properties: the proximal first pipe segment prioritizes high-modulus materials to ensure delivery; the middle inner layer needs to balance strength and toughness; and the distal third pipe segment focuses on radioactivity and flexural strength. This differentiated material strategy synergistically supports the three-segment functional design. When selecting the above materials, ensuring a Shore hardness range of 45D to 70D is sufficient.

[0057] Furthermore, the elastomer 2221 is one or more of polyolefin elastomers, polyurethane elastomers, polyamide elastomers, silicone, or rubber, with a hardness range of Shore A 15A to 90A. The core criterion for elastomer selection is to achieve a balance between low elastic modulus and large deformation capacity while meeting biosafety requirements. Polyurethane materials are preferred due to their excellent creep resistance and fatigue resistance, while silicone provides more extreme softness. This material combination can be optimized for different clinical scenarios.

[0058] Furthermore, the third tube segment 23 has a tapered tip at the end furthest from the Luer connector 1. This tapered design not only reduces tissue penetration resistance but, more importantly, creates a smooth transition with the sheath tip. This gradual change in cross-section significantly reduces scraping of the sheath opening when the dilating catheter is withdrawn from the sheath, fundamentally reducing the risk of sheath displacement.

[0059] In some examples, the reproducibility of the third segment 23 may be higher than that of the first segment 21, and the material may be an oxide of barium, tungsten and / or its oxides, and / or an oxide of bismuth.

[0060] During use, when the proximal end of the sheath is locked with the Luer connector 1 of the dilator provided in this application, the third segment 23 at the distal end of the dilator protrudes from the distal end of the sheath, combining the sheath with the dilator. When the distal tip penetrates the skin and other human tissues, the dilator is subjected to axial pressure. At this time, due to the presence of the inner layer 221 and the support rod 2222 of the outer layer 222 of the second segment 22, and the fact that its material hardness is higher than that of the first segment, the flexible segment can maintain sufficient compressive strength, allowing the dilator to maintain its support performance under axial pressure. Furthermore, because the outer layer 222 of the second segment 22 has branches and an elastomer 2221, the presence of both gives the tube good resistance to bending even under stress.

[0061] When the sheath and dilator catheter successfully penetrate human tissue and reach the lesion site, the dilator catheter is withdrawn from the sheath. Due to the elastic body 2221 in the second tube segment 22, the tube has good flexibility, which can prevent the sheath angle from changing when the catheter is withdrawn from the sheath, ensuring that the distal end of the sheath can remain in the predetermined position.

[0062] It is readily understood that, based on the several embodiments provided in this application, those skilled in the art can combine, split, or reorganize the embodiments of this application to obtain other embodiments, none of which exceed the protection scope of this application.

[0063] The above detailed embodiments further illustrate the purpose, technical solution, and beneficial effects of the embodiments of this application. It should be understood that the above are merely specific embodiments of the embodiments of this application and are not intended to limit the protection scope of the embodiments of this application. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solutions of the embodiments of this application should be included within the protection scope of the embodiments of this application.

Claims

1. A dilation catheter with high axial support, characterized in that, include: Luer joint (1); The expansion tube section (2) is connected to the Luer connector (1); The expansion pipe section (2) includes a first pipe section (21), a second pipe section (22) and a third pipe section (23) arranged sequentially in a direction away from the Luer joint (1); The second pipe segment (22) includes an inner layer (221) and an outer layer (222) covering the outside of the inner layer (221); The outer layer (222) is provided with an elastomer (2221), the hardness of which is lower than that of the inner layer (221), the first pipe segment (21) and the third pipe segment (23).

2. The dilation catheter with high axial support according to claim 1, characterized in that, The outer layer (222) includes a support rod (2222); the support rod (2222) is arranged along the axis parallel to the second pipe segment (22), and the two ends of the support rod (2222) are respectively connected to the first pipe segment (21) and the third pipe segment (23); one side of the support rod (2222) is connected to the inner layer (221).

3. The expansion catheter with high axial support according to claim 2, characterized in that, The support rod (2222) includes an axial portion (22221) and at least one branch portion (22222); the two ends of the axial portion (22221) are respectively connected to the first pipe segment (21) and the third pipe segment (23); one end of the branch portion (22222) is connected to the axial portion (22221), and the other end extends circumferentially along the second pipe segment (22).

4. The expansion catheter with high axial support according to claim 3, characterized in that, Multiple support rods (2222) are provided, and an elastic body (2221) is provided between two adjacent support rods (2222); the elastic body (2221) is evenly arranged along the circumference of the second pipe section (22).

5. A high axial support dilation catheter according to any one of claims 2-4, characterized in that, The support rod (2222) and the inner layer (221) are integrally formed.

6. A high axial support dilation catheter according to any one of claims 2-4, characterized in that, The support rod (2222) and the inner layer (221) are connected by adhesive or welding.

7. The expansion catheter with high axial support according to claim 4, characterized in that, The number of support rods (2222) is 3 to 8.

8. The expansion catheter with high axial support according to claim 1, characterized in that, The first pipe section (21), the inner layer (221) and the third pipe section (23) are respectively one of PE pipe, PP pipe, PI pipe, PEEK pipe, PTFE pipe and PVDF pipe.

9. A high axial support dilation catheter according to claim 1, characterized in that, The elastomer (2221) is one or more of polyolefin elastomers, polyurethane elastomers, polyamide elastomers, silicone or rubber.

10. A high axial support dilation catheter according to claim 1, characterized in that, The third pipe section (23) has a tapered tip at the end away from the Luer joint (1).

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