Stent for assisting balloon catheter in hooping and balloon catheter and manufacturing method thereof

Abstract

The invention discloses a stent for assisting back-holding of a balloon tube. The stent comprises a stent body, a connecting section and a balloon bonding section. The whole stent body is of a tubular structure and is used for being arranged outside the balloon tube expansion section in a sleeving mode, a net-shaped structure is formed on the surface of the stent body, and the stent body can be pushed by the balloon tube expansion section to deform and be unfolded. Balloon bonding sections are arranged at the two ends of the stent body respectively, and connecting sections are arranged between the stent body and the balloon bonding sections. The balloon bonding section is used for being connected with pins at the two ends of a balloon tube, and the connecting section is used for being arranged outside the pins of the balloon tube in a sleeving mode; the connecting section has axial elastic force larger than that of the support body. The invention further discloses a balloon catheter comprising the stent and a manufacturing method of the balloon catheter. Protrusions of the stent body can be reduced, flexibility is improved, the balloon tube can be repeatedly filled, and the hooping outer diameter is not changed.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a stent for assisting the retraction of a balloon tube, a balloon catheter and a manufacturing method thereof. Background Art

[0002] Angioplasty is a method used to restore narrowed blood vessels to their original shape, also known as balloon angioplasty. It is a minimally invasive procedure that mainly uses the physical expansion of a balloon tube to remove obstacles in narrowed or blocked arteries and play a role in plaque cleaning.

[0003] In the prior art, the constrained balloon catheter includes a balloon tube, a catheter, and a stent disposed outside the balloon tube. The stent is attached to the outer surface of the balloon tube and can expand with the expansion of the balloon tube to constrain the overall expansion of the balloon tube. The existing balloon tube will increase in outer diameter after repeated filling and re-embracing, and the connection is prone to warping and is not round, which increases the pushing force and has the risk of damaging blood vessels. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides a stent for assisting the re-embracement of a balloon tube, a balloon catheter and a manufacturing method thereof, which can reduce the protrusion of the stent body, increase flexibility, and can repeatedly fill the balloon tube without changing the re-embrace outer diameter.

[0005] The first aspect of the present invention is to provide a stent for assisting the retraction of a balloon tube, comprising a stent body, a connecting section and a balloon bonding section;

[0006] The stent body is in a tubular structure as a whole, and is used to be sheathed on the outside of the balloon tube expansion section. The surface of the stent body forms a mesh structure, which can be deformed and expanded under the push of the balloon tube expansion section;

[0007] The balloon bonding sections are respectively provided at both ends of the stent body, and the connecting section is provided between the stent body and the balloon bonding section; the balloon bonding section is used to connect with the pins at both ends of the balloon tube, and the connecting section is used to be sleeved on the outside of the balloon tube pins; the connecting section has an axial elastic force greater than that of the stent body.

[0008] In the first aspect of the present invention, as a preferred embodiment, compensation sections are respectively formed at both ends of the stent body, and the compensation sections are used to compensate for the covering length of the stent body on the balloon tube when the stent body is expanded.

[0009] In the first aspect of the present invention, as a preferred embodiment, the connecting section is a wave-shaped, spiral-shaped, single or multiple diamond-shaped structure.

[0010] In the first aspect of the present invention, as a preferred embodiment, the connecting section is composed of a plurality of groups of radially folded wavy structures, and the number of the wavy structures is adapted to the number of folded petals of the balloon.

[0011] In the first aspect of the present invention, as a preferred embodiment, a coating is attached to the stent, and the coating is the same drug coating as that of the drug-loaded balloon.

[0012] A second aspect of the present invention provides a balloon catheter, comprising a stent and a balloon tube as described in any one of the first aspects of the present invention, wherein the stent is sleeved on the outside of the balloon tube.

[0013] In the second aspect of the present invention, as a preferred embodiment, the balloon tube includes an expansion section and a tube pin, and the two tube pins are respectively arranged at both ends of the expansion section for connecting with the stent; the stent is sleeved on the surface of the balloon tube to form a balloon with a stent;

[0014] It also includes a catheter assembly, which includes an inner tube, an outer tube and a Y-shaped connector; the inner tube is inserted into the outer tube, and a gap is formed between the inner tube and the outer tube for filling fluid to pass through; one end of the catheter assembly is connected to the Y-shaped connector, and the other end of the catheter assembly is inserted into the balloon with a stent; a liquid hole is provided at the connection between the outer tube and the balloon tube, and the liquid hole can allow filling fluid to pass through to expand the balloon.

[0015] A third aspect of the present invention provides a method for manufacturing a balloon catheter, comprising the following steps:

[0016] The outer tube preparation step includes injecting a polyurethane reaction substance into a gap between two coaxially arranged metal tube core rods, adding a porogen to the polyurethane reaction substance during the injection process, wherein the ratio of the porogen to the polyurethane reaction substance is 0.5% to 20%, and soaking the mixture in injection water for 5 to 24 hours after curing and forming to obtain the outer tube;

[0017] The steps of preparing the inner tube are as follows: coating a polytetrafluoroethylene coating on the surface of a metal tube core rod; then processing a spring layer and a braided layer on the surface of the metal tube core rod; extruding a molten plastic layer on the surface of the braided layer so that the molten plastic is wrapped on the surface of the braided layer, and cooling and solidifying to obtain the inner tube;

[0018] Preparation steps of the stent: designing a 2D cutting drawing of the stent based on the diameter data of the balloon tube in the contracted state and the expanded state and the length data of the expanded section; laser cutting the substrate to obtain a cut piece based on the cutting drawing; and subjecting the cut piece to heat treatment and sandblasting to obtain the stent;

[0019] The step of bonding the stent to the balloon tube is as follows: the stent is sheathed on the outside of the balloon tube, and the pins at both ends of the balloon tube are bonded to the balloon bonding sections at both ends of the stent respectively; thus, the balloon tube with the stent is obtained;

[0020] The step of bonding the balloon tube with the stent to the outer tube is as follows: connecting the balloon tube with the stent to the end of the outer tube, and forming a liquid hole at the connection between the balloon tube and the outer tube;

[0021] The steps of connecting the outer tube and the inner tube are as follows: the inner tube is inserted into the outer tube, the inner tube extends from the far end of the outer tube to form an extension section, and the extension section is fixedly connected to the end of the outer tube by a metal welding machine;

[0022] The processing steps of the inner tube extension section are as follows: removing the plastic layer and part of the braided layer on the surface of the extension section by laser, and applying a plastic coating on the surface of the spring layer and the braided layer exposed in the extension section;

[0023] The bonding step of the joint is to install the Y-type joint on the proximal ends of the outer tube and the inner tube.

[0024] In the third aspect of the present invention, as a preferred embodiment, the step of preparing the inner tube specifically comprises the following steps:

[0025] Step S21: providing a metal tube core rod, denoted as a third metal tube core rod, coating a polytetrafluoroethylene coating on the surface of the third metal tube core rod, wherein the thickness of the polytetrafluoroethylene coating is preferably 10 μm to 20 μm;

[0026] Step S22: Processing a spring layer on the surface of the metal tube core rod, wherein the thickness of the spring layer is 20 μm to 30 μm;

[0027] Step S23: cross-weaving metal flat wires on the surface of the spring layer to form a braided layer, the thickness of the braided layer is 30 μm to 60 μm, and a first semi-finished product is obtained;

[0028] Step S24: sleeve the first semi-finished product on the outside of the core shaft of the extruder, and extrude the molten plastic onto the surface of the first semi-finished product through the extruder to form a molten plastic layer;

[0029] The surface of the first semi-finished product and the molten plastic layer are squeezed by a double roller machine, and the molten plastic is wrapped on the surface of the braided layer to obtain a second semi-finished product; after cooling and solidification, the third metal tube core rod is pulled out to obtain an inner tube.

[0030] In the third aspect of the present invention, as a preferred embodiment, the step of bonding the balloon tube with the stent to the outer tube specifically comprises the following steps:

[0031] Step S51: providing a metal tube core rod, which is referred to as a fourth metal tube core rod, and sleeve the fourth metal tube core rod onto the end of the outer tube;

[0032] Step S52: providing a heat shrink tube, preferably a fluorinated ethylene propylene heat shrink tube, and sleeve the heat shrink tube on the end of the outer tube, which is the end with the fourth metal tube core rod inside; using a hot air blower to heat the end, the heat shrink tube shrinks due to the heat, and drives the end of the outer tube to deform and fit the surface of the fourth metal tube core rod, so that the end of the outer tube forms a reduced diameter section, the diameter of the reduced diameter section is smaller than the diameter of the outer tube, and the length of the reduced diameter section is preferably 10 to 30 cm; after the reduced diameter section is cooled and solidified, the heat shrink tube is peeled off, and the fourth metal tube core rod is withdrawn;

[0033] Step S53: providing a plurality of liquid-passing holes for liquid circulation on the surface of the reduced diameter section;

[0034] Step S54: sleeve the balloon tube with the stent on the outside of the reduced diameter section, and evenly bond the tube pin of the balloon tube to the end of the reduced diameter section with medical glue, so that the flow hole is located inside the balloon tube after bonding.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. The stent body of the present invention is deformed when the balloon is inflated. The deformation is respectively manifested as an axial shortening and a radial enlargement of the stent body, thereby generating an axial tensile force and a radial retraction force. The radial retraction force assists the balloon tube in retraction, while the axial tensile force generated at the same time will increase the fatigue strength of the stent body, causing it to deform and reduce its service life. The present invention provides a connecting section, and the connecting section has an axial elastic force greater than that of the stent body. When the stent body is expanded, the connecting section connected at both ends of the stent body is stretched, so that the connecting section is deformed, thereby transferring the axial elastic force on the stent body. At the same time, the connecting section is elongated to compensate for the axial deformation of the stent body, thereby preventing the stent body from causing elastic fatigue and warping due to multiple expansion and contraction, which affects the pushing of the stent inside the blood vessel.

[0037] 2. The present invention provides a stent that can assist the retraction of a balloon, a balloon catheter having the stent, and a method for manufacturing the balloon catheter. The stent of the present invention can be used to assist the retraction of a quick delivery balloon or an OTW structure balloon. Since the outer diameter of the balloon will increase after filling and it is not circular, which increases the pushing force and the risk of damage, the stent is provided outside the balloon to solve this problem. And by providing a connecting section, the protrusion of the stent body is reduced and the flexibility is increased. The present invention can repeatedly fill the balloon without changing the outer diameter of the retraction, and can be used for conveying equipment to reduce the frequency of exchange of other equipment. At the same time, after filling, it can guide large-caliber catheters. When filled, the present invention can make the balloon expand more evenly, reduce the dog bone effect and reduce the risk of dissection. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the structure of the stent capable of assisting balloon retraction of the present invention;

[0039] Figure 2 It is a partial schematic diagram of the A part of the stent capable of assisting the balloon retraction of the present invention;

[0040] Figure 3 It is a schematic structural diagram of another angle of the stent capable of assisting the balloon to re-embrace of the present invention;

[0041] Figure 4 It is a partial schematic diagram of the B portion of the stent capable of assisting balloon retraction of the present invention;

[0042] Figure 5 It is a left view of the stent capable of assisting balloon retraction of the present invention;

[0043] Figure 6 It is a schematic diagram of the deployment state of the stent capable of assisting balloon retraction of the present invention;

[0044] Figure 7 Another embodiment of the connection section of the stent capable of assisting balloon re-embrace of the present invention;

[0045] Figure 8 This is another embodiment of the connecting section of the stent capable of assisting balloon re-embracement of the present invention;

[0046] Fig. 9 It is a schematic structural diagram of the balloon tube of the balloon catheter of the present invention.

[0047] In the figure: 11, stent body; 12, connecting section; 13, balloon bonding section; 20, balloon tube; 21, expansion section; 22, tube pin; 30, catheter assembly; 31, inner tube; 32, outer tube. DETAILED DESCRIPTION

[0048] Below, in conjunction with the accompanying drawings and specific embodiments, the invention is further described. It should be noted that, under the premise of no conflict, the various embodiments described below or the various technical features can be arbitrarily combined to form a new embodiment. Except as otherwise specified, the materials and equipment used in this embodiment can be purchased from the market. Examples of the embodiments are shown in the accompanying drawings, in which the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0049] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present application. In the description of the present application, "plurality" means two or more, unless otherwise precisely and specifically specified.

[0050] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, or it can be connected through an intermediary medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0051] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0052] Embodiment 1:

[0053] refer to Figures 1 to 9 As shown, this embodiment provides a stent for assisting the re-embracement of a balloon tube, comprising an integrally formed stent body 11, a connecting section 12 and a balloon bonding section 13;

[0054] The stent body 11 is annular as a whole and is used to be sheathed on the outside of the expansion section 21 of the balloon tube 20. A mesh structure is formed on the surface of the stent body 11. The mesh structure has a plurality of square, rectangular or diamond-shaped units, which can be deformed and expanded under the push of the expansion section 21 of the balloon tube 20.

[0055] Balloon bonding sections 13 are respectively provided at both ends of the stent body 11, and connecting sections 12 are provided between the stent body 11 and the balloon bonding sections 13 at both ends; the balloon bonding sections 13 are used to connect with the tube pins 22 at both ends of the balloon tube 20, and the stent body 11 connected with the balloon tube 20 covers the expansion section 21 of the balloon tube 20, and the connecting section 12 is sleeved outside the tube pin 22; the connecting section 12 has an axial elastic force greater than that of the stent body 11;

[0056] The stent body 11 of this embodiment is deformed when the balloon is inflated. The deformation is respectively manifested as the axial shortening and radial enlargement of the stent body 11, thereby generating axial tensile force and radial retraction force. The radial retraction force assists the balloon tube 20 in retraction, and the axial tensile force generated at the same time will increase the fatigue strength of the stent body 11 to deform it or reduce its service life. In this embodiment, a connecting section 12 is provided, and the connecting section 12 has an axial elastic force greater than that of the stent body 11. When the stent body 11 is inflated, the connecting section 12 connected at both ends is stretched, and the connecting section 12 is deformed, thereby transferring the axial elastic force on the stent body 11. At the same time, the connecting section 12 is stretched to compensate for the axial deformation of the stent body 11, thereby preventing the stent body 11 from elastic fatigue and warping due to multiple expansion and contraction, which affects the pushing of the stent inside the blood vessel.

[0057] Furthermore, compensation sections are formed at both ends of the stent body 11, respectively. The compensation sections make the stent body 11 exceed the length of the expansion section 21 of the balloon tube 20 when the stent body 11 is contracted, and compensate the axial length of the stent body 11 when the stent body 11 is expanded, so that the stent body 11 completely covers the expansion section 21 of the balloon tube 20, avoiding the dog-bone effect caused by the stent body 11 not covering both ends.

[0058] Specifically, the connecting section 12 can be a wavy, spiral, single or multiple diamond-shaped structure. The connecting section 12 of this embodiment is composed of multiple groups of radially folded wavy structures. The radially folded wavy axial connection point is small, which can provide greater axial elastic force. The gaps between the multiple groups of wavy structures can compensate for the radial deformation generated when the connecting section 12 is deformed, avoiding compression of the balloon tube 20 pin 22 that penetrates the inside. Furthermore, the number of wavy structures can be increased or decreased according to the number of folded flaps of the balloon to match the compression of the balloon flap. The connecting section 12 can be supported by a memory nickel-titanium alloy to improve the structural stability of the stent.

[0059] In some preferred embodiments, the stent may be coated with the same drug coating as the drug-loaded balloon, or may be subjected to a hydrophilic coating.

[0060] Embodiment 2:

[0061] Based on Example 1, this embodiment provides a balloon catheter, including a catheter assembly 30, a balloon tube 20, and the stent for assisting the balloon tube to re-embrace as described in Example 1;

[0062] The balloon tube 20 includes an expansion section 21 and a tube pin 22. The two tube pins 22 are respectively arranged at both ends of the expansion section 21 for connecting with the stent. The stent is sleeved on the surface of the balloon tube 20 to form a balloon with a stent.

[0063] The catheter assembly 30 includes an inner tube 31, an outer tube 32 and a Y-type connector; the inner tube 31 is inserted into the outer tube 32, and a gap is formed between the inner tube 31 and the outer tube 32 for the filling fluid to pass through. One end of the catheter assembly 30 is connected to the Y-type connector, and the other end is inserted into the inside of the balloon with a stent. A liquid hole is provided at the connection between the outer tube 32 and the balloon tube 20, and the liquid hole can allow the filling fluid to pass through to expand the balloon.

[0064] Embodiment 3:

[0065] This embodiment provides a method for manufacturing a balloon catheter based on Example 2, which is mainly used to manufacture the balloon catheter described in Example 2. The balloon catheter includes the stent for assisting the balloon tube to retract as described in Example 1. The method for manufacturing the balloon catheter in this embodiment includes the following steps:

[0066] S1: Step of preparing the outer tube 32, specifically comprising:

[0067] S11: providing two metal tube core rods, respectively referred to as a first metal tube core rod and a second metal tube core rod, wherein the diameter of the first metal tube core rod is larger than that of the second metal tube core rod, and the first metal tube core rod is sleeved outside the second metal tube core rod and coaxially arranged to form a gap between the two metal tube core rods;

[0068] S12: providing a main constituent material for the middle layer. The main constituent material of the middle layer in this embodiment is a polyurethane reaction material, and the polyurethane reaction material includes a mixture of a polyol component and an isocyanate component;

[0069] S13: injecting the main constituent material of the middle layer into the gap formed between the two metal tube core rods through an injection machine; at the same time, continuously adding a porogen to the mixture during the injection process, the ratio of the porogen to the mixture is preferably 0.5% to 20%, waiting for the cross-linking reaction to be completed, the mixture is solidified and formed into a tubular object, and the tubular object is soaked in injection water for 5 to 24 hours to fully remove the residual porogen, thereby obtaining an outer tube 32;

[0070] S14: The outer tube 32 is subjected to a water lubrication coating treatment.

[0071] S2: Step of preparing the inner tube 31, specifically comprising:

[0072] S21: providing a metal tube core rod, denoted as a third metal tube core rod, coating a polytetrafluoroethylene coating on the surface of the third metal tube core rod, wherein the thickness of the polytetrafluoroethylene coating is preferably 10 μm to 20 μm;

[0073] S22: Processing a spring layer on the surface of the metal tube core rod, wherein the thickness of the spring layer is 20 μm to 30 μm;

[0074] S23: cross-weaving metal flat wires on the surface of the spring layer to form a braided layer, the thickness of the braided layer is 30 μm to 60 μm, and a first semi-finished product is obtained;

[0075] S24: sleeve the first semi-finished product on the outside of the core shaft of the extruder, and extrude the molten plastic onto the surface of the first semi-finished product through the extruder to form a molten plastic layer;

[0076] The surface of the first semi-finished product and the molten plastic layer are extruded by a double roller machine, and the molten plastic is wrapped on the surface of the braided layer to obtain a second semi-finished product; after cooling and solidification, the third metal tube core rod is pulled out to obtain an inner tube 31.

[0077] S3: scaffold preparation step, specifically including:

[0078] S31: Design a 2D cutting drawing of the stent based on the diameters of the balloon tube 20 in the contracted state and the expanded state.

[0079] S32: Provide a stent material tube, laser cut the stent material tube according to the stent 2D cutting drawing to obtain a cut piece; heat treat the cut piece to make it super elastic; polish the heat-treated cut piece on a sandblasting machine to make it smooth to obtain a stent, the stent includes a balloon bonding section 13, a connecting section 12 and a stent body 11, and both ends of the stent body 11 are connected to the balloon bonding section 13 through the connecting section 12.

[0080] S4: The step of bonding the stent and the balloon tube 20 includes:

[0081] S41: The stent is sheathed outside the balloon tube 20, and the position is adjusted so that the tube pins 22 at both ends of the balloon tube 20 overlap with the balloon bonding sections 13 at both ends of the stent respectively;

[0082] S42: Provide a heat shrink tube, preferably a fluorinated ethylene propylene heat shrink tube, and sleeve the heat shrink tube on the outside of the tube pins 22 at both ends of the balloon tube 20 and the balloon bonding sections 13 at both ends of the stent. Use a hot air blower to heat the heat shrink tube. The heat shrink tube shrinks and makes the tube pins 22 at both ends of the balloon tube 20 and the balloon bonding sections 13 at both ends of the stent adhere together. After cooling, peel off the heat shrink tube to obtain the balloon tube 20 with the stent.

[0083] S5: The step of bonding the balloon tube 20 with the stent to the outer tube 32 specifically includes:

[0084] S51: Provide a metal tube core rod, which is referred to as the fourth metal tube core rod, and sleeve the fourth metal tube core rod on the end of the outer tube 32.

[0085] S52: Provide a heat shrink tube, preferably a fluorinated ethylene propylene heat shrink tube, and sleeve the heat shrink tube on the end of the outer tube 32, which end is the end with a fourth metal tube core rod installed inside; use a hot air blower to heat the end, and the heat shrink tube shrinks due to the heat, causing the end of the outer tube 32 to deform and fit the surface of the fourth metal tube core rod, thereby forming a reduced diameter section at the end of the outer tube 32, the diameter of the reduced diameter section is smaller than the diameter of the outer tube 32, and the length of the reduced diameter section is preferably 10 to 30 cm; after the reduced diameter section is cooled and solidified, peel off the heat shrink tube and withdraw the fourth metal tube core rod.

[0086] S53: a plurality of liquid passage holes for liquid circulation are arranged on the surface of the reduced diameter section.

[0087] S54: The balloon tube 20 with the stent is sleeved on the outside of the reduced diameter section, and the pin 22 of the balloon tube 20 is evenly bonded to the end of the reduced diameter section by medical glue, so that the flow hole is located inside the balloon tube 20 after bonding.

[0088] S6: The step of connecting the outer tube 32 and the inner tube 31 includes:

[0089] S61: insert the inner tube 31 into the outer tube 32, and the end of the inner tube 31 extends from one end of the reduced diameter section to form an extended section, and the extended section is preferably 15 to 25 cm;

[0090] S62: inserting a metal welding machine mandrel from the end of the extended section, the head end of the metal welding machine mandrel can overlap the portion of the inner tube 31 extending from the reduced diameter section, and providing a heat shrink tube sleeved on the end of the extended section and the end of the reduced diameter section; heating the metal welding machine to connect the end of the inner tube 31 with the end of the reduced diameter section of the outer tube 32, wherein the welding temperature of the metal welding machine is 90°C to 200°C, and the welding time is 10s to 30s;

[0091] S7: The processing steps of the extended section of the inner tube 31 specifically include:

[0092] S71: providing a metal core rod, and inserting the metal core rod into the extension section; irradiating the extension section with a laser, thereby removing the plastic layer and part of the braided layer on the surface of the extension section;

[0093] S72: A plastic coating is applied to the exposed surfaces of the spring layer and the braided layer of the extended section; thereby making the end portion smooth and flexible, eliminating the influence of welding on the end portion, and preventing the end portion from damaging the blood vessel.

[0094] S8: The bonding step of the joint includes:

[0095] S81: Provide a Y-type connector, and apply a layer of medical glue on the distal contact surface of the Y-type connector, the proximal contact surface of the Y-type connector, the outer side of the proximal end of the outer tube 32, and the outer side of the proximal end of the inner tube 31; the proximal end of the outer tube 32 is the end of the outer tube 32 away from the balloon tube 20; the proximal end of the inner tube 31 is the end of the inner tube 31 away from the balloon tube 20;

[0096] S82: Extend the proximal ends of the inner tube 31 and the outer tube 32 from the distal main inner hole of the Y-type connector to the corresponding assembly position, and then bond and fix them with medical glue.

[0097] When in use, the filling liquid is introduced into the gap between the inner tube and the outer tube 32 through the Y-shaped joint, and the filling liquid enters the interior of the balloon through the liquid hole to fill it.

[0098] The present invention provides a stent that can assist the retraction of a balloon, a balloon catheter having the stent, and a method for manufacturing the balloon catheter. The stent of the present invention can be used for assisting the retraction of a quick delivery balloon or an OTW structure balloon. Since the outer diameter of the current balloon will increase after filling and will not be circular, which increases the pushing force and the risk of damage, the stent is provided outside the balloon to solve this problem. And by providing a connecting section 12, the protrusion of the stent body 11 is reduced to increase flexibility. The present invention can repeatedly fill the balloon without changing the outer diameter of the retraction, and can be used for conveying equipment to reduce the frequency of exchange of other equipment. At the same time, after filling, it can guide large-caliber catheters. When filled, the present invention can make the balloon expand more evenly, reduce the dog bone effect, and reduce the risk of dissection.

[0099] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A stent for assisting the retraction of a balloon tube, characterized in that: It includes a stent body, a connecting section and a balloon bonding section; The stent body is in a tubular structure as a whole, and is used to be sheathed on the outside of the balloon tube expansion section. The surface of the stent body forms a mesh structure, which can be deformed and expanded under the push of the balloon tube expansion section; The balloon bonding sections are respectively provided at both ends of the stent body, and the connecting section is provided between the stent body and the balloon bonding section; the balloon bonding section is used to connect with the pins at both ends of the balloon tube, and the connecting section is used to be sleeved on the outside of the balloon tube pins; the connecting section has an axial elastic force greater than that of the stent body.

2. A stent for assisting the retraction of a balloon tube according to claim 1, characterized in that: Compensation sections are respectively formed at both ends of the stent body, and the compensation sections are used to compensate for the covering length of the stent body on the balloon tube when the stent body is expanded.

3. A stent for assisting the retraction of a balloon tube according to claim 1, characterized in that: The connecting section is a wave-shaped, spiral-shaped, single or multiple diamond-shaped structure.

4. A stent for assisting the retraction of a balloon tube according to claim 3, characterized in that: The connecting section is composed of a plurality of groups of radially folded wavy structures, and the number of the wavy structures matches the number of folded petals of the balloon.

5. A stent for assisting the retraction of a balloon tube according to claim 1, characterized in that: The stent is attached with a coating, which is the same drug coating as that of the drug-loaded balloon.

6. A balloon catheter, characterized in that: It comprises the stent and the balloon tube as described in any one of claims 1 to 5, wherein the stent is sleeved on the outside of the balloon tube.

7. A balloon catheter according to claim 6, characterized in that: The balloon tube comprises an expansion section and a tube pin, and the two tube pins are respectively arranged at both ends of the expansion section for connecting with the stent; the stent is sleeved on the surface of the balloon tube to form a balloon with a stent; It also includes a catheter assembly, which includes an inner tube, an outer tube and a Y-shaped connector; the inner tube is inserted into the outer tube, and a gap is formed between the inner tube and the outer tube for filling fluid to pass through; one end of the catheter assembly is connected to the Y-shaped connector, and the other end of the catheter assembly is inserted into the balloon with a stent; a liquid hole is provided at the connection between the outer tube and the balloon tube, and the liquid hole can allow filling fluid to pass through to expand the balloon.

8. A method for manufacturing a balloon catheter, characterized in that: The following steps are involved: The outer tube preparation step includes injecting a polyurethane reaction substance into a gap between two coaxially arranged metal tube core rods, adding a porogen to the polyurethane reaction substance during the injection process, wherein the ratio of the porogen to the polyurethane reaction substance is 0.5% to 20%, and soaking the mixture in injection water for 5 to 24 hours after curing and forming to obtain the outer tube; The inner tube is prepared by coating a polytetrafluoroethylene coating on the surface of a metal tube core rod; Then, a spring layer and a braided layer are processed on the surface of the metal tube core rod; A molten plastic layer is squeezed into the surface of the braided layer, so that the molten plastic is wrapped around the surface of the braided layer, and the inner tube is obtained after cooling and solidification; Preparation steps of the stent: designing a 2D cutting drawing of the stent based on the diameter data of the balloon tube in the contracted state and the expanded state and the length data of the expanded section; laser cutting the substrate to obtain a cut piece based on the cutting drawing; and subjecting the cut piece to heat treatment and sandblasting to obtain the stent; The step of bonding the stent to the balloon tube is as follows: the stent is sheathed on the outside of the balloon tube, and the pins at both ends of the balloon tube are bonded to the balloon bonding sections at both ends of the stent respectively; thus, the balloon tube with the stent is obtained; The step of bonding the balloon tube with the stent to the outer tube is as follows: connecting the balloon tube with the stent to the end of the outer tube, and forming a liquid hole at the connection between the balloon tube and the outer tube; The steps of connecting the outer tube and the inner tube are as follows: the inner tube is inserted into the outer tube, the inner tube extends from the far end of the outer tube to form an extension section, and the extension section is fixedly connected to the end of the outer tube by a metal welding machine; The processing steps of the inner tube extension section are as follows: removing the plastic layer and part of the braided layer on the surface of the extension section by laser, and applying a plastic coating on the surface of the spring layer and the braided layer exposed in the extension section; The bonding step of the joint is to install the Y-type joint on the proximal ends of the outer tube and the inner tube.

9. The method for manufacturing a balloon catheter according to claim 8, characterized in that: The step of preparing the inner tube specifically comprises the following steps: Step S21: providing a metal tube core rod, denoted as a third metal tube core rod, coating a polytetrafluoroethylene coating on the surface of the third metal tube core rod, wherein the thickness of the polytetrafluoroethylene coating is preferably 10 μm to 20 μm; Step S22: Processing a spring layer on the surface of the metal tube core rod, wherein the thickness of the spring layer is 20 μm to 30 μm; Step S23: cross-weaving metal flat wires on the surface of the spring layer to form a braided layer, the thickness of the braided layer is 30 μm to 60 μm, and a first semi-finished product is obtained; Step S24: sleeve the first semi-finished product on the outside of the core shaft of the extruder, and extrude the molten plastic onto the surface of the first semi-finished product through the extruder to form a molten plastic layer; The surface of the first semi-finished product and the molten plastic layer are squeezed by a double roller machine, and the molten plastic is wrapped on the surface of the braided layer to obtain a second semi-finished product; after cooling and solidification, the third metal tube core rod is pulled out to obtain an inner tube.

10. The method for manufacturing a balloon catheter according to claim 9, characterized in that: The step of bonding the balloon tube with the stent to the outer tube specifically includes the following steps: Step S51: providing a metal tube core rod, which is referred to as a fourth metal tube core rod, and sleeve the fourth metal tube core rod onto the end of the outer tube; Step S52: providing a heat shrink tube, preferably a fluorinated ethylene propylene heat shrink tube, and sleeve the heat shrink tube on the end of the outer tube, which is the end with the fourth metal tube core rod inside; using a hot air blower to heat the end, the heat shrink tube shrinks due to the heat, and drives the end of the outer tube to deform and fit the surface of the fourth metal tube core rod, so that the end of the outer tube forms a reduced diameter section, the diameter of the reduced diameter section is smaller than the diameter of the outer tube, and the length of the reduced diameter section is preferably 10 to 30 cm; after the reduced diameter section is cooled and solidified, the heat shrink tube is peeled off, and the fourth metal tube core rod is withdrawn; Step S53: providing a plurality of liquid-passing holes for liquid circulation on the surface of the reduced diameter section; Step S54: sleeve the balloon tube with the stent on the outside of the reduced diameter section, and evenly bond the tube pin of the balloon tube to the end of the reduced diameter section with medical glue, so that the flow hole is located inside the balloon tube after bonding.

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