Delivery device and method for a vascular stent

Abstract

The application provides a vascular stent delivery device and a delivery method. The vascular stent delivery device comprises a pushing assembly, a restraint catheter and a sleeve assembly which are sequentially nested from inside to outside. The restraint catheter comprises a delivery part at a proximal end and a restraint part at a distal end. The sleeve assembly is rotatably sleeved on a part of the outer surface of the delivery part. The pushing assembly comprises a limiting main pipe. The proximal end of the limiting main pipe is located in the delivery part, and the distal end of the limiting main pipe extends out of the restraint part. A tubular stent is sleeved on the outer peripheral wall of the part of the limiting main pipe located in the restraint part, so that the tubular stent is accommodated in the restraint part. The restraint catheter moves along the axial direction of the limiting main pipe to release the accommodation of the tubular stent. The application adopts a coaxial multi-layer structure design, has good supportability and is more easily passed through a lesion.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology and relates to a vascular stent delivery device and delivery method. Background Technology

[0002] Lower extremity arteriosclerosis obliterans is a common disease in vascular surgery. The main cause is atherosclerosis of the lower extremity arteries, leading to narrowing and blockage of blood vessels, insufficient blood supply, and chronic ischemia of the limbs, which can even result in amputation in severe cases. Compared to traditional endarterectomy, percutaneous endovascular stenting has advantages such as shorter operation time, less trauma, and fewer postoperative complications. It can effectively dilate narrowed blood vessels and restore normal blood flow.

[0003] In percutaneous transluminal stent placement surgery, substandard stent delivery systems frequently result in problems such as stent deformation, kinking, bending, and displacement. Furthermore, currently available conventional stent delivery systems often suffer from insufficient pushing force during stent deployment, leading to incomplete deployment of long stents and requiring manual levering to complete the process. However, this two-stage deployment increases the risk of stent deformation, kinking, and breakage, raising the difficulty of the procedure for surgeons and posing greater risks to patients.

[0004] Therefore, it is very important to provide a delivery device that is easy to operate and can avoid the problem of deformation during support release. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a vascular stent delivery device and delivery method. The device employs a coaxial four-layer structure design, which provides good support and facilitates passage through lesions. At the same time, it reduces the risk of the entire system twisting and becoming unstable in tortuous lesions, as is common in traditional designs.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a vascular stent delivery device, the vascular stent delivery device comprising a push assembly, a restraint catheter and an outer sleeve assembly arranged in sequence from the inside to the outside, the push assembly being used to support a tubular stent, and the restraint catheter being used to accommodate the push assembly loaded with the tubular stent.

[0008] The restraint catheter includes a delivery portion at a proximal end and a restraint portion at a distal end. The outer sleeve assembly is rotatably fitted onto a portion of the outer surface of the delivery portion. The push assembly includes a limiting main tube, the proximal end of which is located within the delivery portion, and the distal end of which extends out of the restraint portion. A tubular stent is fitted onto a portion of the outer peripheral wall of the limiting main tube located within the restraint portion, such that the tubular stent is housed within the restraint portion. The restraint catheter moves axially along the limiting main tube to release the housed tubular stent.

[0009] The vascular stent delivery device provided by this invention mounts a clamped tubular stent onto a limiting main tube. A restraining catheter is fitted around the periphery of the limiting main tube containing the tubular stent. The pushing component and the restraining catheter have a nested structure, which improves support performance and facilitates passage through the lesion site. The end of the limiting main tube extending beyond the restraining catheter acts as a guide, enabling the entire delivery device to accurately reach the lesion site. Before reaching the lesion site, the tubular stent is in a contracted state and housed within the restraining portion. After reaching the lesion site, the restraining catheter retracts, releasing the tubular stent, which then returns to its expanded state, completing stent delivery. The outer sleeve component provides torque and strong support while offering a lower surface friction coefficient, reducing release resistance.

[0010] It should be noted that, in this invention, the proximal end refers to the end facing the surgeon during surgery, while the distal end refers to the end facing the patient.

[0011] As a preferred embodiment of the present invention, the pushing component further includes an ejector tube located within the delivery section, the ejector tube being nested at the proximal end of the limiting tube, and the distal end of the ejector tube being provided with a protrusion.

[0012] Preferably, the diameter of the protrusion is greater than or equal to the diameter of the ejector tube.

[0013] The ejector tube in this invention can be sleeved on the outer layer of the limiting tube, which can be a separate connected double-layer structure, or the ejector tube and the limiting tube can be melted by rheoforming to obtain an integrally formed irregular tube, which can provide good support and pushing performance.

[0014] Preferably, the protrusion includes a combination of at least two of the first developing element, the covering element, and the filler element.

[0015] Preferably, the protrusion includes a first developing element and a covering element.

[0016] As a preferred embodiment of the present invention, the material of the first developing element includes any one or a combination of at least two of tantalum, gold, platinum or platinum alloy, wherein typical but non-limiting combinations include: tantalum and platinum alloy, tantalum and platinum, gold and platinum, and tantalum, gold and tantalum mixtures, etc.

[0017] Preferably, the material of the covering includes a heat-shrinkable material.

[0018] The present invention does not specifically limit the selection of heat-shrinkable materials, including but not limited to FEP (fluorinated ethylene propylene copolymer), PET (polyethylene terephthalate), etc. Of course, it is understood that other heat-shrinkable materials that can be used in the support conveying device also fall within the protection scope and disclosure scope of the present invention. Therefore, other heat-shrinkable materials that have been disclosed in the prior art or not disclosed in the new technology can also be used in the present invention.

[0019] The covering component of the present invention can be a tubular structure surrounding the distal end of the ejector tube. After heat shrinking, a smooth surface is obtained, which reduces frictional resistance, reduces harm to the human body, and enhances the bonding force between the components.

[0020] Preferably, the filler comprises a polymer material doped with a developing agent.

[0021] Preferably, the polymer material includes, but is not limited to, PA12 (polydodecanoic acid lactam) or Pebax (block polyether amide).

[0022] Preferably, the developing material includes, but is not limited to, BaSO4 or bismuth oxide, with a doping ratio of 10% to 40%.

[0023] As a preferred embodiment of the present invention, a hollow cavity is formed inside the limiting main tube, the hollow cavity is used to accommodate the wire, and a guide is provided at one end of the limiting main tube extending out of the binding part.

[0024] Preferably, the limiting main tube and the guide part are integrally formed.

[0025] Preferably, the limiting main tube and the guide part are fixed by bonding, welding or fitting.

[0026] Preferably, the guide portion has a tapered structure.

[0027] In this invention, the guide part is pre-embedded in the limiting main pipe, and the distal end is conical, which makes it easier to pass through the lesion site.

[0028] As a preferred embodiment of the present invention, the limiting main tube includes a polymer single tube or a composite tube.

[0029] Preferably, the polymer single tube includes any one of PEEK (polyetheretherketone), Pebax, or PA12.

[0030] Preferably, the composite tube includes a substrate, and the outer surface of the substrate is provided with at least one protective layer.

[0031] Preferably, the substrate comprises PTFE (polytetrafluoroethylene).

[0032] Preferably, the material of the guide portion includes any one or a combination of at least two of PU, Pebax, tungsten powder, or barium sulfate.

[0033] As a preferred embodiment of the present invention, the binding catheter has a variable diameter structure, wherein the inner diameter of the binding part is larger than the inner diameter of the delivery part.

[0034] In this invention, the binding catheter adopts a variable diameter structure, with the distal binding part being a thicker end to increase the load space of the stent, improve release performance, and reduce release force, while the proximal delivery part is a thinner end for superior pushing performance.

[0035] Preferably, the constricting catheter is a single-layer catheter or a composite catheter with at least two layers.

[0036] Preferably, a second developing element is provided at the distal end of the binding portion.

[0037] As a preferred embodiment of the present invention, the binding catheter is a three-layer composite catheter, consisting of an inner tube, a middle tube, and an outer tube from the inside out.

[0038] Preferably, the material of the inner tube includes any one or a combination of at least two of high-density polyethylene (HDPE), nylon, polytetrafluoroethylene, silicone resin, or polyether block amide.

[0039] Preferably, the intermediate tube is formed by spiral weaving or winding of polymer and / or metal wire.

[0040] Preferably, the outer tube is made of any one or a combination of at least two of the following materials: high-density polyethylene, nylon, polytetrafluoroethylene, silicone resin, or polyether block amide.

[0041] In this invention, the inner tube of the constricting catheter provides good lubrication performance, the middle tube is formed by polyethylene polymer and / or metal braiding or winding, which can improve the support and pushability of the catheter, and the outer tube further optimizes the support performance.

[0042] As a preferred embodiment of the present invention, the outer diameter of the binding part is larger than the inner diameter of the outer jacket assembly.

[0043] The outer sheath assembly of this invention is circumferentially rotating relative to the restraint catheter, providing torque and strong support. During use, the outer sheath assembly contacts the sheath. When encountering a tortuous lesion, the restraint catheter can freely twist to release overall stress, while the outer sheath assembly and sheath remain relatively stationary. This reduces the risk of overall system twisting and release instability in conventional designs when adapting to tortuous lesions. The inner diameter of the restraint portion is larger than the inner diameter of the outer sheath assembly, preventing the restraint portion from entering the outer sheath assembly during the release of the tubular stent, thus avoiding excessive retraction of the restraint catheter.

[0044] It should be noted that the outer casing component in this invention can be a single layer or a composite structure with at least two layers.

[0045] In a second aspect, the present invention provides a method for delivering a vascular stent, wherein the method uses the vascular stent delivery device described in the first aspect to deliver a tubular stent, and the method includes:

[0046] The compressed tubular stent is fitted onto the distal end of the limiting main tube, so that the tubular stent is housed within the binding portion of the binding catheter.

[0047] The pushing component is delivered to the lesion site, and the restraint portion is close to the lesion site;

[0048] The restraint catheter is driven to retract axially along the limiting main tube to release the tubular stent.

[0049] As a preferred embodiment of the present invention, the specific delivery method of the push component includes:

[0050] The guidewire is inserted into the hollow cavity of the limiting tube, and the first imaging element located at the distal end of the tube and the second imaging element located at the distal end of the binding catheter are observed, so that the binding part is close to the lesion site.

[0051] Preferably, during the driving process, the delivery portion of the restraint catheter moves axially within the outer sheath assembly, and the first imaging element located at the distal end of the ejector tube and the second imaging element located at the distal end of the restraint catheter are observed to determine the movement distance so that the tubular stent is completely released.

[0052] It should be noted that the retraction mentioned in this invention refers to the process in which the delivery part of the restraint catheter moves axially towards the proximal end within the drive sheath assembly to expose the tubular stent and release the tubular stent.

[0053] This invention does not impose specific limitations or special requirements on the driving component and driving method for retracting the restraint catheter. Driving components disclosed in the prior art or not disclosed in new technologies can be used in this invention. To help those skilled in the art better understand the overall technical solution and working process of this invention, the invention provides the following exemplary driving method for the driving component for retracting the restraint catheter:

[0054] The driving component may include a rotating handle and a guide rod. The guide rod is connected to the proximal end of the restraint catheter. The inner surface of the rotating handle is provided with an internal thread, and the outer surface of the guide rod is provided with an external thread. The internal and external threads mesh with each other to achieve a rotational connection between the rotating handle and the guide rod. When the rotating handle is configured to rotate in a first direction, the guide rod retracts, thereby driving the restraint catheter to move proximally and release the tubular stent. When the rotating handle is configured to rotate in a second direction, the guide rod advances, thereby driving the restraint catheter to move distally to restrain the tubular stent.

[0055] It should be noted that the driving component is not limited to having the above structure. Any component that can achieve the same or similar function can be arbitrarily replaced, and the technical solution obtained after replacement also falls within the protection scope and disclosure scope of this invention.

[0056] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0057] This invention provides a vascular stent delivery device and method. A clamped tubular stent is mounted on a limiting main tube. A restraining catheter is fitted around the periphery of the limiting main tube containing the tubular stent. One end of the limiting main tube extends beyond the restraining catheter, acting as a guide to ensure accurate delivery to the lesion site. Before reaching the lesion site, the tubular stent is in a contracted state and contained within the restraining portion. Upon reaching the lesion site, the restraining catheter moves, releasing the tubular stent, which then returns to its expanded state, completing stent delivery. This invention improves support performance, enhances the ability to traverse lesion sites, and reduces the risk of system distortion and release instability in tortuous lesions, common in traditional designs. Attached Figure Description

[0058] Figure 1 This is a schematic diagram of the delivery device for accommodating a tubular stent provided in Embodiment 1 of the present invention;

[0059] Figure 2 This is a schematic diagram of the delivery device for releasing a tubular stent in the form of a vascular stent, as provided in Embodiment 1 of the present invention.

[0060] Figure 3 This is a schematic diagram of the structure of the limiting main tube provided in Embodiment 1 of the present invention;

[0061] Figure 4 This is a schematic diagram of the ejector tube provided in Embodiment 1 of the present invention;

[0062] Figure 5 This is a schematic diagram of the structure of the protrusion provided in Embodiment 1 of the present invention;

[0063] Figure 6 This is a schematic diagram of the binding catheter provided in Embodiment 1 of the present invention;

[0064] Figure 7 This is a schematic diagram of the limiting main tube and the ejection main tube provided in Embodiment 3 of the present invention.

[0065] Among them, 1-limiting main tube; 11-guide part; 2-ejection main tube; 21-protrusion part; 221-first imaging element; 222-covering element; 3-binding catheter; 31-binding part; 32-delivery part; 4-outer sleeve assembly. Detailed Implementation

[0066] It should be understood that in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0067] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0068] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0069] In one specific embodiment, the present invention provides a vascular stent delivery device, comprising a push assembly, a restraint catheter 3 and an outer sleeve assembly 4 arranged in a nested manner from the inside out. The push assembly is used to support the tubular stent, and the restraint catheter 3 is used to accommodate the push assembly loaded with the tubular stent.

[0070] The restraint catheter 3 includes a delivery portion 32 at the proximal end and a restraint portion 31 at the distal end. The outer sleeve assembly 4 is rotatably fitted onto a portion of the outer surface of the delivery portion 32. The push assembly includes a limiting main tube 1, the proximal end of which is located within the delivery portion 32, and the distal end of which extends out of the restraint portion 31. A tubular stent is fitted onto a portion of the outer peripheral wall of the limiting main tube 1 located within the restraint portion 31, such that the tubular stent is housed within the restraint portion 31. The restraint catheter 3 moves axially along the limiting main tube 1 to release the housing of the tubular stent.

[0071] The vascular stent delivery device provided by this invention mounts a clamped tubular stent onto a limiting main tube 1. A restraining catheter 3 is fitted around the periphery of the limiting main tube 1 containing the tubular stent. The pushing component and the restraining catheter 3 have a nested structure, which improves support performance and makes it easier to pass through the lesion site. The end of the limiting main tube 1 extending out of the restraining catheter 3 acts as a guide, enabling the entire delivery device to accurately reach the lesion site. Before reaching the lesion site, the tubular stent is in a contracted state and housed within the restraining part 31. After reaching the lesion site, the restraining catheter 3 moves, releasing the tubular stent, which then returns to its expanded state, completing the stent delivery. The outer sleeve assembly 4 provides torque and strong support, while also providing a lower surface friction coefficient, reducing release resistance.

[0072] In this invention, the proximal end refers to the end facing the surgeon during surgery, and the distal end refers to the end facing the patient.

[0073] In some embodiments, the pushing component further includes an ejector tube 2 located within the delivery section 32, the ejector tube 2 being nested at the proximal end of the limiting tube 1, and the distal end of the ejector tube 2 being provided with a protrusion 21. The diameter of the protrusion 21 is greater than or equal to the diameter of the ejector tube 2.

[0074] In this invention, the ejector tube 2 can be sleeved on the outer layer of the limiting tube 1, which is a separate, movable, double-layer structure. Alternatively, the ejector tube 2 and the limiting tube 1 can be melted together by rheoforming to obtain an integrally formed irregular tube, which can provide good support and pushing performance.

[0075] In some embodiments, the protrusion 21 includes a combination of at least two of the first developing element 221, the covering element 222, and the filler element.

[0076] In some embodiments, the protrusion 21 includes a first developing element 221 and a covering element 222.

[0077] In some embodiments, the material of the first developing element 221 includes any one or a combination of at least two of tantalum, gold, platinum, or platinum alloys.

[0078] The material of the covering 222 includes heat-shrinkable materials. This invention does not specifically limit the selection of heat-shrinkable materials, including but not limited to FEP, PET, etc. It is understood that other heat-shrinkable materials that can be used in the support conveying device also fall within the protection and disclosure scope of this invention. Therefore, other heat-shrinkable materials disclosed in the prior art or not disclosed in new technologies can also be used in this invention. The covering 222 of this invention can be a tubular structure surrounding the distal end of the ejector main tube 2. After heat shrinking, it obtains a smooth surface, reduces frictional resistance, minimizes harm to the human body, and enhances the bonding force between the components.

[0079] In some embodiments, the filler comprises a polymer material doped with a developing agent.

[0080] In some embodiments, the polymer material includes PA12 or Pebax, and the developing substance includes BaSO4 or bismuth oxide, etc., with a doping ratio of 10% to 40%.

[0081] In some embodiments, a hollow cavity is formed inside the limiting main tube 1 to accommodate the wire, and a guide part 11 is provided at one end of the limiting main tube 1 extending out of the binding part 31.

[0082] In some embodiments, the limiting main tube 1 and the guide part 11 are integrally formed.

[0083] In some embodiments, the limiting main tube 1 and the guide part 11 are fixed by bonding, welding or fitting.

[0084] In some embodiments, the guide portion 11 has a conical structure. In this invention, the guide portion 11 is pre-embedded in the limiting main pipe 1, and its distal end is conical, making it easier to pass through the lesion site.

[0085] In some embodiments, the limiting main tube 1 includes a polymer single tube or a composite tube.

[0086] In some embodiments, the polymer single tube includes any one of PEEK, Pebax, or PA12.

[0087] In some embodiments, the composite tube includes a substrate, the outer surface of which is provided with at least one protective layer. The substrate includes PTFE.

[0088] In some embodiments, the guide portion 11 is made of any one or a combination of at least two of PU, Pebax, tungsten powder, or barium sulfate.

[0089] In some embodiments, the restraint catheter 3 has a variable diameter structure, with the inner diameter of the restraint portion 31 being larger than the inner diameter of the delivery portion 32. In this invention, the restraint catheter 3 adopts a variable diameter structure, with the distal restraint portion 31 being a thicker end, increasing the stent load space, improving release performance, and reducing release force, while the proximal delivery portion 32 is a thinner end, resulting in superior pushing performance.

[0090] In some embodiments, the restraint catheter 3 is a single-layer catheter or a composite catheter with at least two layers.

[0091] In some embodiments, a second developing element is provided at the distal end of the binding portion 31.

[0092] In some embodiments, the binding conduit 3 is a three-layer composite conduit, consisting of an inner tube, a middle tube, and an outer tube from the inside out. The inner tube is made of any one or a combination of at least two of high-density polyethylene, nylon, polytetrafluoroethylene, silicone resin, or polyether block amide. The middle tube is formed by spiral braiding or winding of a polymer and / or metal wire. The inner tube is also made of any one or a combination of at least two of high-density polyethylene, nylon, polytetrafluoroethylene, silicone resin, or polyether block amide. In this invention, the inner tube, middle tube, and outer tube may be made of the same material or different materials.

[0093] In this invention, the inner tube of the binding catheter 3 provides good lubrication performance, the middle tube is formed by polyethylene polymer and / or metal braiding or winding, which can improve the support and pushability of the catheter, and the outer tube further optimizes the support performance.

[0094] In some embodiments, the outer diameter of the restraint portion 31 is larger than the inner diameter of the outer sleeve assembly 4. The outer sleeve assembly 4 of the present invention is circumferentially rotating relative to the restraint catheter 3, providing torque and strong support. During use, the outer sleeve assembly 4 contacts the sheath. When encountering a tortuous lesion, the restraint catheter 3 can freely twist to release overall stress, while the outer sleeve assembly 4 remains relatively stationary with respect to the sheath. This reduces the risk of overall system distortion and release instability in conventional designs when adapting to tortuous lesions. Because the outer diameter of the restraint portion 31 is larger than the inner diameter of the outer sleeve assembly 4, the restraint portion 31 cannot enter the outer sleeve assembly 4 during the release of the tubular stent, preventing excessive retraction of the restraint catheter 3.

[0095] The outer casing component 4 in this invention can be a single layer or a composite structure with at least two layers. For example, when the outer casing component 4 adopts a three-layer composite structure, it consists of an inner lining layer, a middle layer, and an outer layer from the inside out. The inner lining layer can be made of PTFE material, the middle layer is formed by woven metal wire, and the material of the outer layer includes, but is not limited to, PEEK, Pebax, or PA12.

[0096] In another specific embodiment, the present invention provides a method for delivering a vascular stent, wherein the delivery method employs a vascular stent delivery device as described in a specific embodiment to deliver a tubular stent, and the delivery method includes:

[0097] The compressed tubular stent is fitted onto the distal end of the limiting main tube 1, so that the tubular stent is housed within the binding portion 31 of the binding catheter 3.

[0098] The pushing component is delivered to the lesion site, and the restraint part 31 is close to the lesion site;

[0099] Drive the restraint catheter 3 to retract axially along the limiting main tube 1 to release the tubular stent.

[0100] The retraction described in this invention refers to the process in which the delivery part 32 of the restraint catheter 3 moves axially towards the proximal end within the drive sheath assembly 4 to expose the tubular stent and release the tubular stent.

[0101] In some implementations, the specific delivery method of the push component includes:

[0102] The guidewire is inserted into the hollow cavity of the limiting main tube 1, and the first imaging element 221 located at the distal end of the ejection main tube 2 and the second imaging element located at the distal end of the binding catheter 3 are observed, so that the binding part 31 is close to the lesion site.

[0103] In some embodiments, during the driving process, the delivery portion 32 of the restraint catheter 3 moves axially within the outer sheath assembly 4, and the first imaging element 221 located at the distal end of the ejection main tube 2 and the second imaging element located at the distal end of the restraint catheter 3 are observed to determine the movement distance so that the tubular stent is completely released.

[0104] This invention does not impose specific limitations or special requirements on the driving component and driving method for retracting the restraint catheter 3. Driving components disclosed in the prior art or not disclosed in new technologies can be used in this invention. In order to help those skilled in the art better understand the overall technical solution and working process of this invention, this invention provides the following exemplary driving method for the driving component for retracting the restraint catheter 3:

[0105] The driving component may include a rotating handle and a guide rod. The guide rod is connected to the proximal end of the restraint catheter 3. The inner surface of the rotating handle is provided with an internal thread, and the outer surface of the guide rod is provided with an external thread. The internal and external threads mesh with each other to achieve a rotational connection between the rotating handle and the guide rod. When the rotating handle is configured to rotate in a first direction, the guide rod retracts, thereby driving the restraint catheter 3 to move proximally and release the tubular stent. When the rotating handle is configured to rotate in a second direction, the guide rod advances, thereby driving the restraint catheter 3 to move distally to restrain the tubular stent.

[0106] Example 1

[0107] This embodiment provides a vascular stent delivery device, such as... Figure 1 and Figure 2 As shown, it includes a limiting main tube 1, an ejection main tube 2, a restraint conduit 3, and an outer casing assembly 4, which are nested from the inside out.

[0108] like Figure 3 As shown, the proximal end of the limiting main tube 1 extends into the ejection main tube 2, and the distal end of the limiting main tube 1 extends out of the restraint part 31 and is provided with a guide part 11. The guide part 11 has a conical structure, is made of PU material with a hardness of 70-90A, and is welded to the limiting main tube 1. The distal end is conical, making it easier to pass through the lesion site. The limiting main tube 1 is made of PEEK material with a wall thickness of 100μm, which has strong support. It has a hollow cavity inside, which can accommodate a 0.035" guidewire.

[0109] like Figure 4 and Figure 5 As shown, the distal end of the ejector tube 2 has a protrusion 21, which consists of a first developing element 221 and a covering element 222. The ejector tube 2 is made of PI material with a wall thickness of 125μm and is fitted onto the outer surface of the limiting tube 1. The two are bonded together using an adhesive process. The developing ring is made of platinum-iridium alloy and is fitted onto the ejector tube 2, also bonded together using an adhesive process. The covering element 222 is made of PET heat shrink tubing and is heated with hot air at 100℃~120℃ for 1~2 minutes, causing the heat shrink tubing to tightly adhere the developing ring and the ejector tube 2.

[0110] like Figure 6 As shown, the restraint catheter 3 has a variable diameter structure, including a delivery part 32 located at the proximal end and a restraint part 31 located at the distal end. The distal restraint part 31 is a thicker end, which increases the load space of the stent, improves release performance, and reduces release force. The proximal delivery part 32 is a thinner end, which makes the pushing performance better.

[0111] The restraint unit consists of 31 three-layer composite tubes, which are arranged from the inside out as an inner tube, a middle tube, and an outer tube. The inner tube is made of PTFE material to provide good lubrication, the middle tube uses a stainless steel braided layer to improve the support and pushing ability of the restraint guide tube 3, and the outer tube is made of PA12 material, with the harder grade ML21 selected to further optimize the support performance.

[0112] The tubular stent is fitted onto the outer peripheral wall of the limiting main tube 1 located in the binding part 31 in a press-fitting manner, so that the tubular stent is housed in the binding part 31. The two ends of the press-fitted tubular stent are reserved with a total of 300mm, which can meet the pressing of stents of different lengths from 40mm to 150mm.

[0113] The outer casing assembly 4 is a three-layer composite tube. The inner lining is made of PTFE material, providing a lower coefficient of surface friction and reducing release resistance. The middle layer is made of stainless steel braided material, and the outer layer is made of PA12 material, specifically the harder grade ML21, to optimize support performance. The outer casing assembly 4 can rotate circumferentially relative to the restraint conduit 3, covering part of the outer surface of the delivery section 32, providing torque and strong support.

[0114] The delivery method of the vascular stent delivery device provided in this embodiment specifically includes:

[0115] The guidewire is inserted into the hollow cavity of the limiting main tube 1. The first imaging element 221 located at the distal end of the ejection main tube 2 and the second imaging element located at the distal end of the restraint catheter 3 are observed. The push assembly is delivered to the lesion site, and the restraint part 31 is close to the lesion site. The delivery part 32 of the restraint catheter 3 is driven to retract axially along the limiting main tube 1 within the outer sleeve assembly 4. The first imaging element 221 located at the distal end of the ejection main tube 2 and the second imaging element located at the distal end of the restraint catheter 3 are observed to determine the movement distance until the tubular stent is completely released.

[0116] Example 2

[0117] This embodiment provides a vascular stent delivery device, which differs from Embodiment 1 in that:

[0118] The ejector main tube 2 is a sodium hypochlorite tube, and the stiffness of the main tube can be adjusted according to the size and spacing of the slits. The ejector main tube 2 and the limiting main tube 1 are bonded together by adhesive. The developing ring of the ejector main tube 2 is welded to the ejector main tube 2 by laser welding. The outer covering 222 of the ejector main tube 2 is made of PET heat shrink tubing, which is heated with hot air at 100℃~120℃ for 1~2 minutes. The heat shrink tubing completely covers the outer surface of the ejector main tube 2 to obtain a smooth surface, reduce frictional resistance, and reduce harm to the human body. The remaining structure is the same as in Example 1, and will not be described again here.

[0119] Example 3

[0120] This embodiment provides a vascular stent delivery device, which differs from Embodiment 1 in that:

[0121] The limiting main pipe 1 uses a double-layer composite pipe. The inner layer is a PTFE liner, providing a smooth channel for the guide wire, and the outer layer is PA12, grade ML21, providing support. The ejection main pipe 2 is made of PA12, grade ML21. Figure 7 As shown, a developing ring is fitted onto the limiting main tube 1. The ejector main tube 2 is fitted onto the outermost layer of the limiting main tube 1, and a one-piece molded tube can be obtained by rheoforming. The ejector main tube 2 and the limiting main tube 1 are fused together to obtain a shaped tube, which can provide good support and pushing performance. The rest of the structure is the same as in Example 1, and will not be described again here.

[0122] Compared to conventional stent release systems, the delivery device provided by this invention employs a coaxial four-layer structure design, offering better support and easier passage through lesions. Conventional delivery systems typically consist of a single-layer outer tube. This invention, however, splits the traditional outer tube into a binding catheter 3 and an outer sheath assembly 4, which can rotate circumferentially relative to the binding catheter 3. In clinical use, the outer sheath assembly 4 contacts the sheath. When encountering tortuous lesions, the binding catheter 3 can freely twist to release overall stress, while the outer sheath assembly 4 remains relatively stationary with respect to the sheath. Furthermore, this reduces the risk of system distortion and unstable release in conventional designs when adapting to tortuous lesions. This invention divides the binding catheter 3 into a delivery section 32 and a binding section 31, featuring a variable diameter structure. This allows the binding section 31 to have a larger inner lumen, meeting the requirements for stent installation, while the delivery section 32 has a smaller outer diameter, ensuring that even with the outer sheath assembly 4, the overall outer diameter of the delivery system remains small, reducing the maximum diameter of the delivery system and improving its ability to pass through lesions.

[0123] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A vascular stent delivery device, characterized in that, The vascular stent delivery device includes a push assembly, a restraint catheter, and an outer sleeve assembly nested from the inside out. The push assembly is used to support the tubular stent, and the restraint catheter is used to accommodate the push assembly loaded with the tubular stent. The binding catheter includes a delivery portion at a proximal end and a binding portion at a distal end. The outer sleeve assembly is rotatably fitted onto a portion of the outer surface of the delivery portion. The outer sleeve assembly is circumferentially rotatable relative to the binding catheter. The pushing assembly includes a limiting main tube, the proximal end of which is located within the delivery portion, and the distal end of which extends out of the binding portion. A tubular support is fitted onto a portion of the outer peripheral wall of the limiting main tube located within the binding portion, such that the tubular support is housed within the binding portion. The binding catheter moves axially along the limiting main tube to release the housing of the tubular support. The binding catheter has a variable diameter structure, with the inner diameter of the binding portion being larger than the inner diameter of the delivery portion. The pushing component also includes an ejector tube located within the delivery section. The ejector tube is nested at the proximal end of the limiting tube, and the distal end of the ejector tube is provided with a protrusion. The ejector tube and the limiting tube are fused together to form an integrally molded irregular tube. The protrusion includes a combination of at least two of a first developing element, a covering element, and a filler element; the material of the first developing element includes any one or a combination of at least two of tantalum, gold, platinum, or platinum alloy; the covering element is a tubular structure surrounding the distal end of the ejector tube, which obtains a smooth surface after heat shrinking to reduce frictional resistance; and the filler element includes a polymer material doped with developing substances.

2. The vascular stent delivery device according to claim 1, characterized in that, The diameter of the protrusion is greater than or equal to the diameter of the ejector tube.

3. The vascular stent delivery device according to claim 1, characterized in that, The material of the covering includes heat-shrinkable material.

4. The vascular stent delivery device according to claim 1, characterized in that, A hollow cavity is formed inside the limiting main tube to accommodate the wire, and a guide is provided at one end of the limiting main tube extending out of the binding part.

5. The vascular stent delivery device according to claim 4, characterized in that, The limiting main tube and the guide part are integrally formed.

6. The vascular stent delivery device according to claim 4, characterized in that, The limiting main tube and the guide part are fixed by bonding, welding or fitting.

7. The vascular stent delivery device according to claim 6, characterized in that, The guide section has a tapered structure.

8. The vascular stent delivery device according to claim 7, characterized in that, The limiting main tube includes a polymer single tube or a composite tube.

9. The vascular stent delivery device according to claim 8, characterized in that, The polymer single tube includes any one of PEEK, Pebax, or PA12.

10. The vascular stent delivery device according to claim 8, characterized in that, The composite tube includes a substrate, and the outer surface of the substrate is provided with at least one protective layer.

11. The vascular stent delivery device according to claim 10, characterized in that, The substrate comprises PTFE.

12. The vascular stent delivery device according to claim 11, characterized in that, The guide part is made of any one or a combination of at least two of the following materials: PU, Pebax, tungsten powder, or barium sulfate.

13. The vascular stent delivery device according to claim 1, characterized in that, The confinement catheter is a single-layer catheter or a composite catheter with at least two layers.

14. The vascular stent delivery device according to claim 13, characterized in that, A second developing element is provided at the distal end of the binding part.

15. The vascular stent delivery device according to claim 14, characterized in that, The binding catheter is a three-layer composite catheter, consisting of an inner tube, a middle tube, and an outer tube from the inside out.

16. The vascular stent delivery device according to claim 15, characterized in that, The inner tube is made of any one or a combination of at least two of the following materials: high-density polyethylene, nylon, polytetrafluoroethylene, silicone resin, or polyether block amide.

17. The vascular stent delivery device according to claim 15, characterized in that, The intermediate tube is formed by spiral weaving of polymer and / or metal wire.

18. The vascular stent delivery device according to claim 15, characterized in that, The intermediate tube is formed by winding a polymer and / or metal wire.

19. The vascular stent delivery device according to claim 15, characterized in that, The outer tube is made of any one or a combination of at least two of the following materials: high-density polyethylene, nylon, polytetrafluoroethylene, silicone resin, or polyether block amide.

20. The vascular stent delivery device according to claim 1, characterized in that, The outer diameter of the restraint part is larger than the inner diameter of the outer garment assembly.

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