Interventional sheath hemostatic valve based on phase change hydrogel and method of assembling the same

Abstract

The application discloses an intervention sheath hemostatic valve based on a phase change hydrogel and an assembling method thereof, and belongs to the technical field of medical devices. The intervention sheath hemostatic valve based on the phase change hydrogel comprises a valve body and a valve core. The valve body is provided with a valve cavity which extends along the axial direction of the valve body and penetrates through two opposite surfaces of the valve body. The valve core is arranged in the valve cavity and is provided with a slit along the axial direction of the valve body, and the slit is used for passing medical intervention instruments. The valve core is made of a phase change hydrogel material, the valve core is in a water absorption and swelling state, and the outer wall of the valve core is in interference fit with the inner wall of the valve cavity. The hemostatic valve provided by the application adopts a water absorption and swelling valve core made of a phase change hydrogel material. The water absorption and swelling valve core not only has an ultra-long service life, a low friction coefficient and extremely low operation resistance when inserting and pulling out intervention instruments, but also has excellent sealing performance and biocompatibility, and has no risk of falling debris during use.

Description

Technical Field

[0001] This application relates to the field of medical device technology, specifically to an interventional sheath hemostatic valve based on phase change hydrogel and its assembly method. Background Technology

[0002] Currently, the catheter sheath used in percutaneous vascular interventional surgery is a key instrument for establishing an external and intravascular access route. The hemostatic valve, as a core component at the sheath's end, primarily functions to prevent blood leakage during repeated insertions and removals of instruments such as guidewires, catheters, and balloons, and to seal the vascular access after instrument withdrawal. Most existing hemostatic valves use valve cores made of medical-grade silicone rubber or thermoplastic elastomer (TPE). However, these materials have the following inherent drawbacks: (1) High frictional resistance: The surface friction coefficient is high, which makes other instruments (such as catheters or guidewires) feel heavy when entering and exiting, affecting the doctor's operating accuracy; (2) Limited tear resistance and self-healing ability: In complex surgery, frequent punctures or long-term placement of large-diameter instruments (such as large balloons and stent delivery systems) can easily lead to permanent deformation, microcracks or even tears in the valve orifice of the valve core, causing blood leakage. (3) Risk of debris: During mechanical puncture, tiny particles (Corning) may be generated, which may enter the blood vessels and cause embolism; (4) Poor sealing adaptability: It does not enclose non-circular cross-section instruments well and is prone to side leakage; (5) Poor sealing of multiple instruments: In stent placement surgery, multiple catheters or guidewires are often required to be inserted at the same time. The valve core made of silicone rubber or thermoplastic elastomer cannot fit well with each instrument, which can easily cause leakage.

[0003] Therefore, developing a safe and reliable interventional sheath hemostatic valve is a pressing problem that needs to be solved in this field. Summary of the Invention

[0004] Based on the deficiencies of the existing technology, the purpose of this application is to provide an interventional sheath hemostatic valve based on phase change hydrogel and its assembly method.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows: In a first aspect of this application, an interventional sheath hemostatic valve based on phase change hydrogel is provided, including a valve body and a valve core; The valve body has a valve cavity that extends axially along the valve body and penetrates two opposing surfaces of the valve body; The valve core is disposed in the valve cavity, and the valve core has a slit along the axial direction of the valve body for medical interventional instruments to pass through. The valve core is made of phase change hydrogel material, and the valve core is in a water-absorbing and swelling state. The outer wall of the valve core is interference-fitted with the inner wall of the valve cavity.

[0006] Preferably, the inner wall of the valve cavity is provided with an annular step, the valve core includes a main body and a protrusion, the main body and the protrusion are integrated, the protrusion is inserted into the annular step, the protrusion is interference-fitted with the inner wall of the annular step, and the main body is in contact with the step surface of the annular step.

[0007] More preferably, a locking post is provided on the step surface of the annular step, and the main body is provided with a locking groove corresponding to the locking post, and the locking post is inserted into the locking groove.

[0008] Preferably, the valve core has an elastic reinforcing rope on the side surface facing away from the annular step.

[0009] Preferably, the valve body has a fluid delivery chamber, which is in communication with the valve chamber.

[0010] Preferably, the interventional sheath hemostasis valve further includes a valve cover, which is connected to the valve body, and the valve cover is provided with a through hole communicating with the valve cavity.

[0011] More preferably, the main body is sandwiched between the valve cover and the annular step.

[0012] In a second aspect, this application provides a method for assembling the aforementioned interventional sheath hemostatic valve, comprising the following steps: Place the dry rigid valve core into the valve cavity of the valve body, and insert the protrusion of the dry rigid valve core into the annular step. The retaining post abuts against the inner wall of one side of the retaining groove. Cover the valve with the valve cover, and then immerse it in deionized water or physiological saline for 10-60 seconds to transform the dry rigid valve core into a water-absorbing and swelling valve core. The outer wall of the water-absorbing and swelling valve core is interference-fitted with the inner wall of the valve cavity. After removal, wipe off the excess water to obtain the interventional sheath hemostatic valve.

[0013] Preferably, the valve core comprises the following raw materials by mass percentage: 5-10% of a first reactive monomer, 15-25% of acrylamide, 0.05-0.2% of a first crosslinking agent, 2-5% of a second crosslinking agent, 0.1-0.3% of an initiator, 0-10% of a plasticizer, and water as the balance. The first reactive monomer comprises at least one of N-acryloyl-L-valine and acrylic acid, and the second reactive monomer comprises acrylamide.

[0014] More preferably, the first crosslinking agent includes N,N'-methylenebisacrylamide; the second crosslinking agent includes at least one of lithium chloride and magnesium chloride.

[0015] Compared with the prior art, the beneficial effects of this application are as follows: The hemostatic valve provided in this application uses a water-absorbing and swelling valve core made of phase change hydrogel material. The water-absorbing and swelling valve core not only has an ultra-long service life and a low coefficient of friction, resulting in extremely low operating resistance when inserting and removing interventional devices, but also has excellent sealing performance and biocompatibility. There is no risk of debris falling during use, making it safer and more reliable. Attached Figure Description

[0016] The embodiments described in this application are not limited to the figures described below, which are only some of the embodiments described in this application. Those skilled in the art can obtain figures of other embodiments based on the content of this application.

[0017] Figure 1 A schematic diagram illustrating the connection between the interventional sheath hemostatic valve and other devices provided in one embodiment of this application; Figure 2 An explosion diagram of the interventional sheath hemostatic valve provided in one embodiment of this application; Figure 3 A perspective view of a valve core provided in one embodiment of this application; Figure 4 This is a schematic diagram of the assembly of the interventional sheath hemostatic valve provided in one embodiment of this application; Figure 5 A schematic diagram of the structure of the interventional sheath hemostasis valve after the valve core swells according to one embodiment of this application; Figure 6 An explosion diagram of a hemostatic valve provided for another embodiment of this application.

[0018] In the diagram, 1-interventional sheath hemostatic valve, 11-valve body, 111-valve cavity, 112-fluid delivery cavity, 113-annular step, 114-locking post, 12-valve core, 121-main body, 122-protrusion, 1211-locking groove, 123-elastic reinforcing rope, 13-valve cover, 131-through hole, 2-sheath, 3-fluid delivery tube, 4-three-way valve. Detailed Implementation

[0019] To better illustrate the purpose, technical solution, and advantages of this application, the following description, in conjunction with specific embodiments and comparative examples, aims to provide a detailed understanding of the content of this application, rather than to limit its scope. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this application.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0021] It is understood that spatial relation terms such as "below," "under," "below," "below," "above," "over," etc., can be used here to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as "below" or "under" or "below" of the other element or feature will be oriented "over" the other element or feature. Therefore, the exemplary terms "below" and "under" can include both upper and lower orientations. Furthermore, the device may also include other orientations (e.g., rotated 90° or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0022] It should be noted that when one element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intermediary element. In the following embodiments, "connection" should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have the transmission of electrical signals or data between them.

[0023] It should be noted that the singular forms of “a,” “one,” and “the” can also include the plural forms, unless the context clearly indicates otherwise.

[0024] It should also be understood that the terms “including / comprise” or “have” specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof.

[0025] It should also be understood that, unless otherwise specified or indicated, the terms "first," "second," "third," etc., in the specification are used only to distinguish the various parts, elements, and steps in the specification, and not to indicate the logical or sequential relationships between the various parts, elements, and steps.

[0026] In the description of this application, it should be noted that the term "distal" usually refers to the end of the medical device that first enters the patient's body during normal operation, while "proximal" usually refers to the end of the medical device that is closer to the operator during normal operation.

[0027] In the first aspect of this application, please refer to Figures 1-6 This application provides an interventional sheath hemostasis valve 1 based on phase change hydrogel, including a valve body 11 and a valve core 12; The valve body 11 has a valve cavity 111, which extends axially along the valve body 11 and penetrates two opposing surfaces of the valve body 11. The valve core 12 is disposed in the valve cavity 13. The valve core 12 has a slit along the axial direction of the valve body 11. The slit is used for medical interventional devices to pass through. The medical interventional devices may include at least one of guide wire and catheter. The valve core 12 is made of phase change hydrogel material. The valve core 12 is a water-absorbing and swelling valve core. The outer wall of the valve core 12 is interference-fitted with the inner wall of the valve cavity 13.

[0028] Before assembly, the valve core 12 is in a dry state. During assembly, the dry valve core 12 is inserted into the valve cavity 13 of the interventional sheath hemostasis valve 1. Then, the interventional sheath hemostasis valve 1 is immersed in physiological saline or rehydration solution. The valve core 12 absorbs water and swells, so that the outer wall of the valve core 12 is press-fitted with the inner wall of the valve cavity 13. At the same time, the valve core 12 has high elasticity and a smooth surface.

[0029] Compared to existing valve cores made of medical-grade silicone rubber or thermoplastic elastomers, the water-absorbing and swelling valve core of this application, made of phase change hydrogel, has the following advantages: (1) Ultra-long service life: The water-absorbing and swelling valve core made of phase change hydrogel material can withstand thousands of puncture cycles without fatigue fracture or leakage. (2) Extremely low operating resistance: The valve core used in this application has high water content and extremely low friction coefficient (less than 0.05), which significantly reduces the friction between the instrument (such as catheter) and the valve core when it enters and exits, making the interventional operation smoother and thus improving the surgical feel.

[0030] (2) Excellent sealing performance: The water-absorbing and swelling valve core made of phase change hydrogel material has a highly tear-resistant network structure, which can adapt to different shapes (such as round and elliptical) and different sizes of interventional instruments (such as guide wires, catheters with a diameter of 0.5mm~8mm, etc.). After the instrument is pulled out, the polymer chains around the slit of the valve core are quickly sufficient under the action of dynamic bonds, which can achieve "second-level" closure, thereby preventing blood backflow, thus achieving zero leakage sealing when alternating interventional instruments, and also achieving zero leakage sealing when multiple catheters and guide wires are intervened at the same time; (3) No risk of debris: The water-absorbing and swelling valve core made of phase change hydrogel material has high elasticity and no risk of debris falling off; (4) Convenient storage and transportation: The valve core made of phase change hydrogel material has the characteristic of "dry hardening". Before assembly, the valve core can be stored in dry solid form without pre-filling with water, which extends the shelf life and reduces packaging costs. (5) Biocompatibility: The phase change hydrogel material of the valve core in this application is not only hydrophilic but also very soft, which can have a small activation effect on blood components and reduce the risk of thrombus formation.

[0031] In one embodiment, the inner wall of the valve cavity 111 is provided with an annular step 113, and the valve core 12 includes a main body 121 and a protrusion 122. The main body 121 and the protrusion 122 are integrated, the protrusion 122 is inserted into the annular step 113, the protrusion 122 is press-fitted with the inner wall of the annular step 113, and the main body 121 is in contact with the step surface of the annular step 113.

[0032] In some embodiments, a locking post 114 is provided on the step surface of the annular step 113, and the main body 121 is provided with a locking groove 1211 corresponding to the locking post 114, into which the locking post 114 is inserted. The locking post 114 and the locking groove 121 form a mechanical interlocking structure, which plays a positioning and limiting role for the valve core 12 during assembly, reducing the difficulty of assembling the interventional sheath hemostatic valve.

[0033] Optionally, the orthographic projection of the slot 1211 onto the valve core 12 axis can be any shape among circles, ellipses, polygons, and unicornuates; the orthographic projection of the main body 121 onto the valve core 12 axis can be any shape among circles, ellipses, polygons, and unicornuates; and the orthographic projection of the protrusion 122 onto the valve core 12 axis can be any shape among circles, ellipses, polygons, and unicornuates. The orthographic projection of the pin 114 onto the valve body 11 axis can be any shape among circles, ellipses, polygons, and unicornuates.

[0034] Optionally, the locking pins 114 correspond one-to-one with the locking slots 1211, and the number of locking slots 1211 is N, where N is a positive integer not less than 2. N is preferably a positive integer not less than 3, and the N locking slots surround the protrusion 122 and are evenly distributed.

[0035] In some embodiments, the valve core 12 has M elastic reinforcing ropes 123 on its surface opposite to the annular step 113, where M is a positive integer not less than 2. The M elastic reinforcing ropes 123 are arranged in an alternating pattern. For example, M is 4, and the 4 elastic reinforcing ropes 123 are arranged in an alternating pattern to form a mesh structure.

[0036] The elastic reinforcing rope 123 can be made of thermoplastic elastomers, such as natural rubber, silicone, TPR, etc. The elastic reinforcing rope 123 improves the compressive strength of the valve core 12.

[0037] In some embodiments, one end of the valve body 11 is connected to a sheath 2, and the inner cavity of the sheath 2 is in communication with the valve cavity 111.

[0038] In some embodiments, the valve body 11 has a fluid delivery chamber 112 that communicates with the valve chamber 111. A fluid delivery pipe 3 is connected to the side end of the valve body 11 and communicates with the fluid delivery chamber 112. A three-way valve 4 is connected to the end of the fluid delivery pipe 3 away from the valve body 11 for delivering medical fluids (such as medical air, medical saline, or medical contrast agents).

[0039] Optionally, the connection between the fluid delivery chamber 112 and the valve chamber 111 is located between the valve core 12 and the sheath 2.

[0040] In some embodiments, the interventional sheath hemostasis valve 1 further includes a valve cover 13, which is disposed at the end of the valve body 11 away from the sheath, and the valve cover 13 is provided with a through hole 131 communicating with the valve cavity 111.

[0041] In some embodiments, the main body 121 is sandwiched between the valve cover 13 and the annular step 113.

[0042] In a second aspect, this application provides a method for assembling the aforementioned interventional sheath hemostatic valve, comprising the following steps: The dry rigid valve core is placed in the valve cavity 111 of the valve body 11, and the protrusion of the dry rigid valve core is inserted into the annular step. The locking post 1 abuts against the inner wall of one side of the locking groove 1211. The valve cover is then placed on top, and the valve is immersed in deionized water or physiological saline for 10-60 seconds to transform the dry rigid valve core into a water-absorbing and swelling valve core. The outer wall of the water-absorbing and swelling valve core is press-fitted with the inner wall of the valve cavity 13. After removal and drying, the interventional sheath hemostatic valve is obtained.

[0043] In some embodiments, the ratio between the radial dimension of the water-absorbing and swelling valve core and the radial dimension of the dry, rigid valve core is (1.4~1.7):1.

[0044] The ratio between the axial dimension of the water-absorbing and swelling valve core and the axial dimension of the dry, rigid valve core is (1.4~1.7):1.

[0045] In some embodiments, the dry rigid valve core comprises the following raw materials by mass percentage: 5-10% first reactive monomer, 15-25% acrylamide, 0.05-0.2% first crosslinking agent, 2-5% second crosslinking agent, 0.1-0.3% initiator, 0-10% plasticizer, and water as the balance.

[0046] The first reactive monomer includes at least one of N-acryloyl-L-valine and acrylic acid.

[0047] The second reactive monomer includes acrylamide.

[0048] The initiator includes ammonium persulfate.

[0049] The first crosslinking agent includes N,N'-methylenebisacrylamide.

[0050] The second crosslinking agent includes at least one of lithium chloride and magnesium chloride.

[0051] The plasticizer includes glycerin.

[0052] The inventors discovered that by selecting at least one of N-acryloyl-L-valine and acrylic acid as the first reactive monomer, the first reactive monomer undergoes polymerization under the action of an initiator, and simultaneously crosslinks with a first crosslinking agent to construct a rigid, porous network structure as a skeleton, which can improve the mechanical strength of the dry-state rigid valve core. In particular, N-acryloyl-L-valine has a chiral structure, which facilitates the formation of strong hydrogen bonds. The higher the mass percentage of the first reactive monomer in the raw materials, the harder the dry-state rigid valve core, but the brittleness increases. When the mass percentage of the first reactive monomer in the raw materials is 8%, the dry-state rigid valve core exhibits better overall performance, higher hardness, and lower brittleness.

[0053] Acrylamide (AAm) was selected as the second reactive monomer. Under the action of an initiator, it undergoes a polymer reaction within the pores of the backbone, simultaneously crosslinking with both the second and first crosslinking agents to construct an interpenetrating double-network structure. This improves the elasticity and self-healing ability of the valve core in a wet state (after water absorption and swelling). The higher the mass proportion of the first reactive monomer in the raw materials, the better the strength of the valve core in a wet state (after water absorption and swelling).

[0054] Introducing the second crosslinking agent in the above-mentioned mass ratio into the raw materials can be used for ionic crosslinking or salting-out effect of the second network, induce phase change, and use the salting-out effect to control the swelling degree of the interventional sheath hemostatic valve in solution (such as deionized water or physiological saline) to prevent excessive expansion of the interventional sheath hemostatic valve.

[0055] Using glycerol as a plasticizer can lower the freezing point. In the preparation process, if freeze-drying is used, it is preferable to introduce 5-10% glycerol into the raw materials to prevent the structure of the double network hydrogel from being destroyed during freeze-drying and to avoid brittleness.

[0056] In some embodiments, the method for preparing the dry hard valve core includes the following steps: S1. Mix the first reaction monomer, the first crosslinking agent, 40-60% of the formulation amount of the initiator and 40-60% of the formulation amount of water to obtain a mixed solution; S2. Inert gas is introduced into the mixed solution obtained in step S1 for deoxygenation treatment; S3. Pour the mixed solution treated in step S2 into a mold and react it in a water bath at 60~70℃ for 1~3 hours to obtain a hydrogel; S4. The second reactant monomer, the second crosslinking agent and the remaining initiator are added to the remaining water and mixed to obtain a precursor solution. The hydrogel obtained in step S3 is immersed in the precursor solution and allowed to stand at 0~10℃ for 18~32h. Then it is reacted at 30~45℃ for 3~5h to obtain a double network hydrogel. S5. The double-network hydrogel obtained in step S4 is washed with water, salted out and dried to obtain a dry rigid valve core.

[0057] In the above preparation method, at 60~70℃, the first reactive monomer undergoes polymerization under the action of an initiator, and simultaneously the first reactive monomer undergoes cross-linking reaction with the first cross-linking agent to form a white, opaque, hard hydrogel with a network structure. Hydrogel A is immersed in a precursor solution, allowing the network structured hydrogel A to fully absorb the precursor solution. In an environment of 30~45℃, the second reactive monomer and the remaining first reactive monomer undergo polymerization under the action of an initiator within the pores of the hydrogel, and simultaneously cross-link with the second cross-linking agent, thereby forming an interpenetrating double network structure to obtain a double network hydrogel. Unreacted monomers and excess salts in the double network hydrogel are removed by washing with water, and then salting out is used to fix the gel, allowing most of the water to be removed. Finally, after drying, a dry, hard valve core is obtained.

[0058] In step S2, the inert gas includes at least one of nitrogen, argon, and helium.

[0059] In step S5, the salting-out shaping step includes immersing the water-washed double-network hydrogel in a salting-out solution for 0.5 to 1 hour. The salting-out solution includes at least one of a saturated sodium chloride solution and an ethanol solution. During the immersion process, utilizing the "salting-out effect" or "dehydration shrinkage," the gel expels most of the water, shrinking its volume to 1 / 2 to 1 / 3 of its original size. The hardness of the salted-out hydrogel increases dramatically, giving it a texture similar to hard plastic.

[0060] In step S5, the drying method includes at least one of air drying and freeze drying. The air drying temperature is 30~45℃.

[0061] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0062] Unless otherwise specified, all experimental reagents and instruments involved in the implementation of this application are commonly used ordinary reagents and instruments.

[0063] Unless otherwise specified, all components and raw materials used in the embodiments and comparative examples of this application are commercially available, and the same type of components and raw materials are used in each parallel experiment.

[0064] Example 1 Please see Figures 1-3 This embodiment provides an interventional sheath hemostasis valve 1 based on phase change hydrogel, including valve body 11, valve core 12 and valve cover 13.

[0065] The valve body 11 has a valve cavity 111, which extends axially along the valve body 11 and penetrates two opposite surfaces of the valve body 11. One end of the valve body 11 is connected to a sheath 2, the inner cavity of which communicates with the valve cavity 111. The valve body 11 also has a fluid delivery cavity 112, which communicates with the valve cavity 111. A fluid delivery pipe 3 is connected to the side end of the valve body 11, communicating with the fluid delivery cavity 112. A three-way valve 4 is connected to the end of the fluid delivery pipe 3 furthest from the valve body 11, used for delivering medical fluids (such as medical air, medical saline, or medical contrast agents). The connection between the fluid delivery cavity 112 and the valve cavity 111 is located between the valve core 12 and the sheath 2.

[0066] A valve cover 13 is located at the end of the valve body 11 away from the sheath 2, and a through hole 131 communicating with the valve cavity 111 is provided on the valve cover 13. A valve core 12 is located in the valve cavity 13, and a slit is opened along the axial direction of the valve body 11 in the valve core 12. The slit is used for medical interventional devices to pass through. The medical interventional device may include at least one of guidewire and catheter. The valve core 12 is made of phase change hydrogel material and is a water-absorbing and swelling valve core. The outer wall of the valve core 12 is interference-fitted with the inner wall of the valve cavity 13.

[0067] The inner wall of the valve cavity 111 is provided with an annular step 113. The valve core 12 includes a main body 121 and a protrusion 122. The main body 121 and the protrusion 122 are integrated. The protrusion 122 is inserted into the annular step 113. The protrusion 122 is press-fitted with the inner wall of the annular step 113. The main body 121 is sandwiched between the valve cover 13 and the annular step 113.

[0068] The annular step 113 has a locking post 114 on its step surface, and the main body 121 has a locking groove 1211 corresponding to the locking post 114. The locking post 114 is inserted into the locking groove 1211. There are 4 locking grooves 1211, which surround the outer periphery of the protrusion 122 and are evenly distributed.

[0069] This embodiment also provides a method for assembling the above-mentioned interventional sheath hemostatic valve, including the following steps: The dry rigid valve core is placed in the valve cavity 111 of the valve body 11, and the protrusion of the dry rigid valve core is inserted into the annular step. The retaining post 1 abuts against the inner wall of one side of the retaining groove 1211. The valve cover is then placed on top, and the assembled interventional sheath hemostatic valve is as follows: Figure 4 As shown, the valve core is then immersed in deionized water or physiological saline for 30 seconds to transform the dry, rigid valve core into a water-absorbing, swollen valve core. The outer wall of the water-absorbing, swollen valve core is press-fitted with the inner wall of the valve cavity 13. After removal, excess water is wiped off, resulting in the swollen interventional sheath hemostatic valve, the structure of which is shown below. Figure 5 As shown.

[0070] The dry-state rigid valve core is made from the following raw materials in the following mass percentages: 8% first reactive monomer, 20% acrylamide, 0.1% first crosslinking agent, 4% second crosslinking agent, 0.2% initiator, and the balance being deionized water, wherein the first reactive monomer is N-acryloyl-L-valine, the second reactive monomer is acrylamide, the initiator is ammonium persulfate, the first crosslinking agent is N,N'-methylenebisacrylamide, and the second crosslinking agent is lithium chloride.

[0071] The preparation method of the dry hard valve core includes the following steps: S1. Mix the first reaction monomer, the first crosslinking agent, 50% of the formulation amount of the initiator, and 50% of the formulation amount of deionized water to obtain a mixed solution; S2. Nitrogen gas is introduced into the mixed solution obtained in step S1 for deoxygenation treatment for 10 min; S3. Pour the mixed solution after step S2 into a mold and react it in a water bath at 65°C for 2 hours to obtain a white, opaque, hard hydrogel with a network structure. S4. The second reactant monomer, the second crosslinking agent and the remaining initiator are added to the remaining deionized water and mixed to obtain a precursor solution. The hydrogel obtained in step S3 is immersed in the precursor solution, allowed to stand at 4°C for 24 h, and then reacted at 37°C for 4 h to obtain a double network hydrogel. S5. The double-network hydrogel obtained in step S4 is washed with water to remove unreacted monomers and excess salt. The washed double-network hydrogel is then immersed in a saturated sodium chloride solution for 1 hour to complete salting out and shaping. Finally, it is dried in an oven at 40°C to constant weight to obtain the dry rigid valve core.

[0072] Example 2 The difference between this embodiment and Embodiment 1 is that, please refer to... Figure 5 In this embodiment, the valve core 12 has four elastic reinforcing ropes 123 made of natural rubber on the side surface away from the annular step 113. The four elastic reinforcing ropes 123 are arranged in pairs to form a mesh structure.

[0073] Example 3 The difference between this embodiment and Embodiment 1 is that, in this embodiment, the preparation method of the dry rigid valve core does not include step S4. In step S5, the hydrogel obtained in step S3 is washed with water to remove unreacted monomers. The washed hydrogel is then immersed in a saturated sodium chloride solution for 1 hour and finally dried in an oven at 40°C to constant weight to obtain the dry rigid valve core.

[0074] To verify the effectiveness of the interventional sheath hemostatic valve in Examples 1-3 above, this application also conducted the following tests: First, immerse the assembled interventional sheath hemostatic valve (which has been soaked in normal saline for 60 seconds to allow the valve core to fully swell); seal the valve chamber 111 at the end connected to the sheath 2 and the fluid delivery chamber 112, then use a filling device to connect and seal the fluid delivery chamber 112, inject normal saline into the other end of the interventional sheath hemostatic valve, and pressurize it to 100 kPa, maintaining the pressure constant; prepare a polymer catheter with a diameter of 8 mm made of medical-grade ABS material; prepare a guidewire with a diameter of 0.8 mm; prepare a small beaker with a graduated capacity greater than 30 ml.

[0075] An 8mm diameter catheter was inserted into the slit of the valve core and inserted and removed 30 times (30 times is far more than the number of times a disposable hemostatic valve catheter can be used). Then, the status of the interventional sheath hemostatic valve was observed when the 8mm catheter was inserted or removed under a pressure of 100kPa. After each insertion or removal, the catheter was left to stand for 30 seconds to observe whether there was any liquid leakage. At the same time, a beaker was used to collect the liquid dripping from the interventional sheath hemostatic valve during the 30 insertions and removals of the catheter to measure the dynamic leakage of saline in the interventional sheath hemostatic valve.

[0076] Finally, after the hemostatic valve has undergone the 8mm catheter insertion and removal test, insert a 0.8mm guidewire, then use a filling device to pressurize the hemostatic valve to 100kPa, and let it stand for 30 seconds to check for any liquid leakage or dripping.

[0077] Test results showed that after 30 cycles of insertion and removal of an 8mm diameter catheter, when the catheter was inserted into or removed from the hemostasis valve, under a pressure of 100kPa, there was no obvious leakage or continuous dripping of saline solution from the hemostasis valve after 30 seconds of stillness. Furthermore, during the 30 cycles of insertion and removal of the catheter, the dynamic leakage of saline solution from the hemostasis valve provided in each embodiment was ≤5ml. This demonstrates that the interventional sheath hemostasis valve provided in each embodiment of this application has excellent sealing performance.

[0078] Finally, after the hemostasis valve underwent the 8mm catheter insertion and removal test, a 0.8mm guidewire was inserted, and the hemostasis valve was pressurized to 100kPa using a filling device. After standing for 30 seconds, the interventional sheath hemostasis valves provided in each embodiment showed no obvious leakage or continuous dripping of saline water droplets.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit the scope of protection of this application. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the substance and scope of the technical solutions of this application.

Claims

1. A hemostatic valve for interventional sheaths based on phase change hydrogel, characterized in that, Includes valve body and valve core; The valve body has a valve cavity that extends axially along the valve body and penetrates two opposing surfaces of the valve body; The valve core is disposed in the valve cavity, and the valve core has a slit along the axial direction of the valve body for medical interventional instruments to pass through. The valve core is made of phase change hydrogel material, and the valve core is in a water-absorbing and swelling state. The outer wall of the valve core is interference-fitted with the inner wall of the valve cavity.

2. The interventional sheath hemostatic valve based on phase change hydrogel as described in claim 1, characterized in that, The inner wall of the valve cavity is provided with an annular step. The valve core includes a main body and a protrusion. The main body and the protrusion are integrated. The protrusion is inserted into the annular step. The protrusion is interference-fitted with the inner wall of the annular step. The main body is in contact with the step surface of the annular step.

3. The interventional sheath hemostatic valve based on phase change hydrogel as described in claim 2, characterized in that, The annular step has a locking post on its surface, and the main body has a locking groove corresponding to the locking post, with the locking post inserted into the locking groove.

4. The interventional sheath hemostatic valve based on phase change hydrogel as described in claim 2, characterized in that, The valve core has an elastic reinforcing rope on the side surface facing away from the annular step.

5. The interventional sheath hemostatic valve based on phase change hydrogel as described in claim 1, characterized in that, The valve body has a fluid delivery chamber, which is connected to the valve chamber.

6. The interventional sheath hemostatic valve based on phase change hydrogel as described in claim 1, characterized in that, It also includes a valve cover, which is connected to the valve body, and the valve cover is provided with a through hole communicating with the valve cavity.

7. The interventional sheath hemostatic valve based on phase change hydrogel as described in claim 6, characterized in that, The main body is sandwiched between the valve cover and the annular step.

8. A method for assembling the interventional sheath hemostatic valve as described in any one of claims 1 to 7, characterized in that, The steps include the following: Place the dry rigid valve core into the valve cavity of the valve body, and insert the protrusion of the dry rigid valve core into the annular step. The retaining post abuts against the inner wall of one side of the retaining groove. Cover the valve with the valve cover, and then immerse it in deionized water or physiological saline for 10-60 seconds to transform the dry rigid valve core into a water-absorbing and swelling valve core. The outer wall of the water-absorbing and swelling valve core is interference-fitted with the inner wall of the valve cavity. After removal, wipe off the excess water to obtain the interventional sheath hemostatic valve.

9. The assembly method of the interventional sheath hemostatic valve as described in claim 8, characterized in that, The valve core comprises the following raw materials by mass percentage: 5-10% first reactive monomer, 15-25% acrylamide, 0.05-0.2% first crosslinking agent, 2-5% second crosslinking agent, 0.1-0.3% initiator, 0-10% plasticizer, and water as balance. The first reactive monomer comprises at least one of N-acryloyl-L-valine and acrylic acid, and the second reactive monomer comprises acrylamide.

10. The assembly method of the interventional sheath hemostatic valve as described in claim 9, characterized in that, The first crosslinking agent includes N,N'-methylenebisacrylamide; the second crosslinking agent includes at least one of lithium chloride and magnesium chloride.

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