A stent for assisting balloon tube retraction, balloon catheter and manufacturing method thereof

Abstract

The present invention discloses a stent for assisting the retraction of a balloon tube, comprising a stent body, a connecting section and a balloon bonding section; the stent body is in an overall tubular structure, and is used to be sheathed on the outside of the balloon tube expansion section. A mesh structure is formed on the surface of the stent body, and can be deformed and unfolded under the push of the balloon tube expansion section; balloon bonding sections are respectively provided at both ends of the stent body, and a connecting section is provided between the stent body and the balloon bonding section; the balloon bonding section is used to connect to the pins at both ends of the balloon tube, and the connecting section is used to be sheathed on the outside of the balloon tube pins; the connecting section has an axial elastic force greater than that of the stent body. The present invention also discloses a balloon catheter including the above-mentioned stent and a method for manufacturing the same. The present invention can reduce the protrusion of the stent body, increase flexibility, and can repeatedly fill the balloon tube without changing the retraction outer diameter.

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 thereof, and a manufacturing method thereof. Background Art

[0002] Angioplasty, also known as balloon angioplasty, is a procedure used to restore narrowed blood vessels to their original shape. It is a minimally invasive procedure that utilizes the physical expansion of a balloon to remove obstructions and plaque from narrowed or blocked arteries.

[0003] Prior art constrained balloon catheters consist of a balloon tube, a catheter, and a stent positioned outside the tube. The stent adheres to the outer surface of the tube and expands with it to constrain its overall expansion. Repeated inflation and retraction can increase the outer diameter of existing balloon tubes, leading to warping at the joints and a loss of circularity. This increases the pushing force and risks 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 retraction of a balloon tube, a balloon catheter thereof, and a manufacturing method thereof, which can reduce the protrusion of the stent body, increase flexibility, and allow the balloon tube to be repeatedly filled without changing the retraction 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 an overall tubular structure, which 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 sections; the balloon bonding sections are 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 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 several 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 the stent according to any one of the first aspects of the present invention and a balloon tube, 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 provided 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 the 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 allows the 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 is prepared by injecting a polyurethane reaction material into a gap between two coaxially arranged metal tube core rods, adding a porogen to the polyurethane reaction material during the injection process, with the ratio of the porogen to the polyurethane reaction material being 0.5% to 20%. After solidification, the outer tube is immersed in injection water for 5 to 24 hours to obtain the outer tube.

[0017] The inner tube preparation steps include: coating a polytetrafluoroethylene coating on the surface of a metal tube core rod; then processing a spring layer and a braid layer on the surface of the metal tube core rod; extruding a molten plastic layer into the surface of the braid layer so that the molten plastic wraps the surface of the braid layer, and cooling and solidifying the inner tube.

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

[0019] The stent and the balloon tube are bonded together by: placing the stent on the outside of the balloon tube, and bonding the pins at both ends of the balloon tube to the balloon bonding sections at both ends of the stent, respectively, to obtain a balloon tube with the stent;

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

[0021] The outer tube and the inner tube are connected by inserting the inner tube into the outer tube, extending the inner tube from the distal end of the outer tube to form an extension section, and fixing the extension section to the end of the outer tube by a metal welder;

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

[0023] In the bonding step of the joint, the Y-type joint is installed at 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 includes the following steps:

[0025] Step S21: providing a metal tube core rod, denoted as a third metal tube core rod, and coating a polytetrafluoroethylene coating on the surface of the third metal tube core rod. 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 spring layer has a thickness of 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 with a thickness of 30 μm to 60 μm, thereby obtaining a first semi-finished product;

[0028] Step S24: sleeve the first semi-finished product onto the outer portion 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 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 includes the following steps:

[0031] Step S51: providing a metal tube core rod, 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 tubing, preferably a fluorinated ethylene propylene heat shrink tubing, and fitting the heat shrink tubing over the end of the outer tube, the end having the fourth metal tube core rod disposed therein; heating the end with a hot air blower, causing the heat shrink tubing to deform and conform to the surface of the fourth metal tube core rod, thereby forming a reduced diameter section at the end of the outer tube. 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 cools and solidifies, the heat shrink tubing is peeled off, and the fourth metal tube core rod is removed;

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

[0034] Step S54: The balloon tube with the stent is placed outside the reduced diameter section, and the pin of the balloon tube is evenly bonded to the end of the reduced diameter section using 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 manifested as the axial shortening and radial enlargement of the stent body, thereby generating axial tensile force and radial retraction force. The radial retraction force assists the balloon tube in retraction, and 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, and the connecting section is deformed, thereby transferring the axial elastic force applied to the stent body. At the same time, the connecting section is elongated to compensate for the axial deformation of the stent body, thereby avoiding elastic fatigue of the stent body 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 in 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 in the retraction of a quick delivery balloon or an OTW structure balloon. Since the outer diameter of the current balloon increases after filling and is not circular, which increases the pushing force and the risk of damage, arranging a stent outside the balloon can solve this problem. And by arranging 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 to transport instruments to reduce the frequency of exchange of other instruments. 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 This is a schematic structural diagram of a stent capable of assisting balloon retraction according to the present invention;

[0039] Figure 2 A partial schematic diagram of portion A of the balloon-assisted stent of the present invention;

[0040] Figure 3 This is a schematic structural diagram of another angle of the stent capable of assisting balloon retraction according to the present invention;

[0041] Figure 4 This is a partial schematic diagram of portion B of the balloon-assisted stent of the present invention;

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

[0043] Figure 6 Schematic diagram of the expanded state of the balloon-assisted stent of the present invention;

[0044] Figure 7 Another embodiment of the connecting section of the stent capable of assisting balloon retraction of the present invention;

[0045] Figure 8 This is another embodiment of the connecting segment of the stent capable of assisting balloon retraction of the present invention;

[0046] Figure 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, the invention is further described in conjunction with the accompanying drawings and specific embodiments. 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. Unless 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 this application, it should be understood that the terms "upper," "lower," "front," "back," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting this application. In the description of this application, "plurality" means two or more, unless otherwise specifically specified.

[0050] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "connected," "connected," and "connected" should be understood in a broad sense. For example, they may refer to a fixed connection, a connection through an intermediary medium, internal communication between two components, or an interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0051] The terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or sequential sequence. In addition, the terms "including," "comprising," and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to the process, method, product, or apparatus.

[0052] Example 1:

[0053] refer to Figures 1 to 9 As shown, this embodiment provides a stent for assisting the retraction 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 in shape and is used to fit over the expansion section 21 of the balloon tube 20. The surface of the stent body 11 forms a mesh structure having multiple 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 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 to the pins 22 at both ends of the balloon tube 20. After the stent body 11 is connected to the balloon tube 20, the expansion section 21 of the balloon tube 20 is covered by the stent body 11, and the connecting section 12 is sleeved outside the pins 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 manifested as the axial shortening and radial enlargement of the stent body 11, thereby generating axial tensile force and radial recoiling force. The radial recoiling force assists the balloon tube 20 in recoiling, and the axial tensile force generated at the same time will increase the fatigue strength of the stent body 11, causing it to deform 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 applied to the stent body 11. At the same time, the connecting section 12 is elongated to compensate for the axial deformation of the stent body 11, thereby avoiding elastic fatigue and warping of the stent body 11 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. The compensation sections allow the stent body 11 to 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 segment 12 can be wavy, spiral, or have a single or multiple diamond-shaped structures. In this embodiment, the connecting segment 12 is composed of multiple groups of radially folded wavy structures. These radially folded wavy structures have smaller axial connection points, providing greater axial elastic force. The gaps between the multiple groups of wavy structures compensate for radial deformation of the connecting segment 12, preventing compression on the pins 22 of the balloon tube 20 inserted within. Furthermore, the number of wavy structures can be increased or decreased based on the number of folded flaps of the balloon to accommodate the compression of the flaps. The connecting segment 12 can be supported by a memory nickel-titanium alloy to enhance 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 hydrophilic coated.

[0060] Example 2:

[0061] This embodiment provides a balloon catheter based on the embodiment 1, including a catheter assembly 30, a balloon tube 20 and the stent for assisting the balloon tube to retract as described in the embodiment 1;

[0062] The balloon tube 20 includes an expansion section 21 and pins 22. The two pins 22 are respectively provided at both ends of the expansion section 21 for connecting with the stent. The stent is sheathed 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-shaped 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-shaped connector, and the other end is inserted into 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] Example 3:

[0065] This embodiment provides a method for manufacturing a balloon catheter based on Example 2. The method 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 of this embodiment includes the following steps:

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

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

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

[0069] S13: The main constituent material of the intermediate layer is injected into the gap formed between the two metal core rods by an injection machine; porogen is continuously added to the mixture during the injection process, with the ratio of porogen to the mixture preferably being 0.5% to 20%. After the cross-linking reaction is completed, the mixture solidifies and forms a tubular object, which is then soaked in injection water for 5 to 24 hours to fully remove any residual porogen, thereby obtaining an outer tube 32;

[0070] S14: Performing a water lubricating coating treatment on the outer tube 32 .

[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, and coating a polytetrafluoroethylene coating on a surface of the third metal tube core rod. 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 spring layer has a thickness of 20 μm to 30 μm;

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

[0075] S24: The first semi-finished product is sleeved on the outside of the core shaft of the extruder, and the molten plastic is extruded onto the surface of the first semi-finished product by the extruder to form a molten plastic layer;

[0076] The surface of the first semi-finished product and the molten plastic layer are squeezed by a 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 the 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 and expanded states.

[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, which 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: Bonding the stent and the balloon tube 20: specifically comprising:

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

[0082] S42: Provide a heat shrink tube, preferably a fluorinated ethylene propylene heat shrink tube, and put 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 bracket. 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 bracket adhere together. After cooling, peel off the heat shrink tube to obtain the balloon tube 20 with the bracket.

[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 onto 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 is the end with the fourth metal tube core rod 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 cools and solidifies, peel off the heat shrink tube and withdraw the fourth metal tube core rod.

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

[0087] S54: The balloon tube 20 with the stent is placed outside the reduced diameter section, and the pin 22 of the balloon tube 20 is evenly bonded to the end of the reduced diameter section using medical glue. After bonding, the flow hole is located inside the balloon tube 20.

[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, with the end of the inner tube 31 extending from one end of the reduced diameter section to form an extended section, which is preferably 15 to 25 cm long;

[0090] S62: Insert a metal welding mandrel from the end of the extended section. The tip of the metal welding mandrel can overlap the portion of the inner tube 31 extending from the reduced diameter section. Provide a heat shrink tubing over the ends of the extended section and the reduced diameter section. Heat the metal welding machine to connect the end of the inner tube 31 to the reduced diameter section of the outer tube 32. The welding temperature of the metal welding machine is 90° C. to 200° C., and the welding time is 10 seconds to 30 seconds.

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

[0092] S71: providing a metal core rod, 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: Apply a plastic coating to the surface of the spring layer and braided layer exposed at the extended section; thereby making the end section smooth and flexible, eliminating the impact of welding on the end section, and preventing the end section from damaging the blood vessel.

[0094] S8: Joint bonding steps, specifically including:

[0095] S81: Provide a Y-shaped connector, and apply a layer of medical glue to the distal contact surface of the Y-shaped connector, the proximal contact surface of the Y-shaped 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-shaped connector to the corresponding assembly positions, and then bond and fix them with medical glue.

[0097] During use, the filling liquid is introduced into the gap between the inner tube and the outer tube 32 through the Y-shaped connector, 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 in 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 in the retraction of a quick delivery balloon or an OTW structure balloon. Since the outer diameter of the current balloon increases after filling and is not circular, which increases the pushing force and the risk of damage, arranging a stent outside the balloon can solve this problem. And by arranging the connecting section 12, the protrusion of the stent body 11 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 to transport instruments to reduce the frequency of exchange of other instruments. 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 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 replacements made by technicians in this field on the basis of the present invention 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 an overall tubular structure, which 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 sections; the balloon bonding sections are used to connect to the pins at both ends of the balloon tube, and the connecting section is used to be sleeved outside the pins of the balloon tube; the connecting section has an axial elastic force greater than that of the stent body; Compensation sections are formed at both ends of the stent body, respectively, 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, so that the stent body can completely cover the expansion section of the balloon tube.

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

3. A stent for assisting the retraction of a balloon tube according to claim 2, 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 is adapted to the number of folded petals of the balloon.

4. The 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.

5. A balloon catheter, characterized in that: It comprises the stent and the balloon tube according to any one of claims 1 to 4, wherein the stent is sleeved on the outside of the balloon tube.

6. A balloon catheter according to claim 5, characterized in that: The balloon tube includes an expansion section and a tube pin, wherein the two tube pins are respectively provided 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 the 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 allows the filling fluid to pass through to expand the balloon.

7. A method for manufacturing a balloon catheter according to claim 5 or 6, characterized in that: The following steps are involved: The outer tube preparation step comprises injecting a polyurethane reaction material into a gap between a first and a second coaxially arranged metal tube core rod, adding a porogen to the polyurethane reaction material during the injection process, wherein the ratio of the porogen to the polyurethane reaction material is (0.5-20):100, and after curing and forming, soaking the outer tube in injection water for 5-24 hours to obtain the outer tube; The inner tube preparation steps include: coating a polytetrafluoroethylene coating on the surface of a third metal tube core rod; and then performing a spring layer processing and a braid layer processing on the surface of the third 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; Stent preparation steps: designing a 2D cutting drawing of the stent based on the diameter data and the length data of the expanded section of the balloon tube in the deflated and expanded states; laser cutting the substrate to obtain a cut piece based on the cutting drawing; and heat treating and sandblasting the cut piece to obtain the stent; The stent and the balloon tube are bonded together by: placing the stent on the outside of the balloon tube, and bonding the pins at both ends of the balloon tube to the balloon bonding sections at both ends of the stent, respectively, to obtain a balloon tube with the stent; The steps of bonding the balloon tube with the stent to the outer tube are as follows: connecting the balloon tube with the stent to the end of the outer tube, wherein a liquid hole is formed at the connection between the balloon tube and the outer tube; The outer tube and the inner tube are connected by inserting the inner tube into the outer tube, extending the inner tube from the distal end of the outer tube to form an extension section, and fixing the extension section to the end of the outer tube by a metal welder; The processing steps of the inner tube extension section are as follows: the plastic layer and part of the braided layer on the surface of the extension section are removed by laser, and the exposed spring layer and braided layer of the extension section are coated with a plastic coating; In the bonding step of the joint, the Y-type joint is installed at the proximal ends of the outer tube and the inner tube.

8. The method for manufacturing a balloon catheter according to claim 7, 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, and coating a polytetrafluoroethylene coating on a surface of the third metal tube core rod, wherein the polytetrafluoroethylene coating has a thickness of 10 μm to 20 μm; Step S22: Processing a spring layer on the surface of the third metal tube core rod, wherein the spring layer has a thickness of 20 μm to 30 μm; Step S23: Cross-weaving metal flat wires on the surface of the spring layer to form a braided layer with a thickness of 30 μm to 60 μm, thereby obtaining a first semi-finished product; Step S24: sleeve the first semi-finished product onto the outer portion 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 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.

9. The method for manufacturing a balloon catheter according to claim 8, 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, 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 tubing, and fitting the heat shrink tubing over the end of the outer tube, where the fourth metal tube core rod is located. Using a hot air blower to heat the end, the heat shrink tubing shrinks and deforms the outer tube end, causing it to adhere to the surface of the fourth metal tube core rod, thereby forming a reduced diameter section at the end of the outer tube. 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 10 to 30 cm. After the reduced diameter section cools and solidifies, the heat shrink tubing is peeled off, and the fourth metal tube core rod is removed. Step S53: providing a plurality of liquid holes for liquid circulation on the surface of the reduced diameter section; Step S54: The balloon tube with the stent is placed outside the reduced diameter section, and the pin of the balloon tube is evenly bonded to the end of the reduced diameter section using medical glue, so that the flow hole is located inside the balloon tube after bonding.

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