A vascular plug assembly

Abstract

The present application relates to a kind of vascular plug assemblies, including multiple vascular plug units, vascular plug unit is connected in series along the axial direction;Vascular plug unit includes: a filling core made of biocompressible material, the woven shell that is covered in the outer filling core, and the center link that is axially through the filling core;The two ends of center link are fixedly connected with the end of woven shell, so that filling core is constrained and packaged in woven shell;Woven shell is woven from shape memory material wire, so that vascular plug unit can be compressed to first radial size, so that vascular plug unit can be transported by sheath tube, after vascular plug assembly is released from sheath tube, woven shell is self-expanded to second radial size, so that woven shell is attached to blood vessel wall, drive filling core to be unfolded to form embolus body together, to block the blood flow of blood vessel.It is convenient to transport by sheath tube, and can ensure the stability of anchoring in blood vessel.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and specifically to a vascular plug assembly. Background Technology

[0002] Vascular embolization is a key technique in interventional therapy used to block pathological blood flow. Its core lies in the precise delivery of embolic material to the target vessel and the achievement of durable and safe occlusion. In addition, embolic devices can fill the false lumen of abdominal aortic aneurysms and aortic dissections; they can block blood flow, fill the volume, promote thrombosis, and shrink the aneurysm and false lumen. Currently, commonly used permanent vascular plugs are mainly divided into two categories: metal braided plugs and polymer-filled plugs. However, both have inherent limitations, making it difficult to achieve an ideal balance between ease of delivery, reliable anchoring, visual imaging, and long-term safety.

[0003] Metallic vascular plugs, especially those made of shape-memory nickel-titanium alloy wires woven into mesh or cage-like structures, are currently widely used. Their advantages lie in the high strength of the alloy, which provides excellent radial support, adapts well to the contraction and relaxation of blood vessels, and has a relatively low risk of displacement after thrombosis. Simultaneously, the dense metal mesh effectively disrupts blood flow, generating turbulence or slowing blood flow velocity, thereby promoting coagulation. However, to achieve effective blood flow disturbance and support, these vascular plugs typically require dense weaving of multiple strands of metal wire, resulting in a large metal volume ratio. Therefore, even under compression, their overall profile remains large, often preventing the use of smaller-diameter minimally invasive delivery sheaths. This necessitates high compatibility with catheter systems, sometimes requiring specialized braided catheters for delivery, limiting their application in thinner or more tortuous vessels. Furthermore, the hollow interior of the metal mesh structure poses a risk of internal recanalization after thrombus organization.

[0004] On the other hand, polymer embolization materials, represented by porous polyurethane foam, exhibit different characteristics as a new type of filler vascular plug. These materials have an extremely low mass-to-volume ratio, possess a certain degree of shape memory and elastic recovery, can be delivered through microcatheters after compression, and self-expand upon release at the target location, exhibiting a high expansion ratio. Their hardness is far lower than that of metals, resulting in less frictional damage to the vascular wall, gentler radial tension, and a lower risk of vascular rupture. Furthermore, they have better biocompatibility, with some materials gradually biodegrading in vivo, avoiding permanent foreign body retention. However, their disadvantages are also significant: the low rigidity of polymers results in weak radial support for thrombi formed within blood vessels, making them prone to displacement due to blood flow impact or vascular pulsation, leading to unstable anchoring and uncontrolled occlusion. Summary of the Invention

[0005] In view of this, the present invention provides a vascular plug assembly that is convenient to be delivered through a sheath and can ensure stable anchoring within the blood vessel.

[0006] The technical solution adopted in this invention:

[0007] A vascular plug assembly includes multiple vascular plug units connected in series along an axial direction; each vascular plug unit includes: a filling core made of a biocompressible material, a braided shell covering the outside of the filling core, and a central connecting rod axially penetrating the filling core; both ends of the central connecting rod are fixedly connected to the ends of the braided shell, thereby constraining and encapsulating the filling core within the braided shell;

[0008] The woven outer shell is made of shape memory material filaments, allowing the vascular plug unit to be compressed to a first radial dimension, enabling delivery of the vascular plug unit through a sheath.

[0009] After the vascular plug assembly is released from the sheath, the braided outer shell expands to a second radial dimension, causing the braided outer shell to conform to the vessel wall, and driving the filling core to unfold together to form an embolus to block blood flow in the vessel.

[0010] Preferably, adjacent vascular plug units are connected in series by a flexible connecting joint at the end of the central connecting rod, so that the series vascular plug units can conform to the curvature of the blood vessel after being deployed.

[0011] Preferably, the flexible connector is a ball-and-socket mating structure, a chain-link structure, or a plug-in structure.

[0012] Preferably, the two ends of the central connecting rod are fixed with developing rings made of platinum-iridium alloy, and the developing rings are exposed outside the filling core.

[0013] Preferably, the woven shell is made of 8 to 24 shape memory material filaments woven in a cross-hatching manner.

[0014] Preferably, the shape memory material filament is selected from one or more of nickel-titanium alloy filament, polydioxanone filament, polyetheretherketone filament, or polyetherketone filament.

[0015] Preferably, the filling core is made of polyurethane foam, and the diameter of the filling core in its unfolded state is 1.2 to 2 times the maximum diameter of the woven shell.

[0016] Preferably, the filling core is prepared by the following steps:

[0017] S100. A polyurethane foam matrix is ​​impregnated in a solution containing the drug, and the drug is carried inside and on the outer surface of the polyurethane foam after curing to obtain a drug matrix; the drug is a procoagulant or antifibrinolytic drug, and the drug is one or more of vitamin K, tranexamic acid, oxidized cellulose, and aminocaproic acid.

[0018] S200. A hydrophilic coating solution is sprayed onto the outer surface of the drug matrix to form a hydrophilic lubricating coating on the outer surface of the drug matrix.

[0019] Preferably, the hydrophilic coating solution comprises resin, photoinitiator, dispersant, and solvent, with a mass ratio of 2-6:0.1-1:0.1-1:92-97.8.

[0020] Preferably, the resin is one or more selected from polyurethane acrylate, polyester acrylate, polyether acrylate, silicone acrylate, and epoxy acrylate resin;

[0021] The photoinitiator is one or more of Irgacure 819, Irgacure 2959, Irgacure 1173, TPO, and BAPO;

[0022] The dispersant is one or more of polyether-modified silicone oil, acrylate-modified silicone oil, acrylate copolymer, and polyoxyethylene ether;

[0023] The solvent is one or more selected from water, methanol, ethanol, isopropanol, n-butanol, butanone, ethyl acetate, butyl acetate, cyclohexane, and n-hexane.

[0024] The beneficial effects of this invention are:

[0025] By employing a core-shell structure that encases a compressible core within a braided shell made of shape memory material fibers, this design minimizes the amount of necessary metal or other rigid materials while maintaining embolization functionality. This allows the entire vascular plug unit to be compressed to an extremely small radial dimension (the first radial dimension), enabling it to pass smoothly through sheaths with smaller inner diameters (e.g., no more than 2 mm). This overcomes the limitation of traditional all-metal braided plugs, which cannot pass through small sheaths due to their large metal volume.

[0026] After the vascular plug assembly is released through the sheath, the self-expanding braided shell first provides immediate and strong radial support, actively adhering to and anchoring to the vessel wall, thus solving the problems of weak anchoring force and easy displacement of pure polymer plugs. Simultaneously, the filling core, constrained within the braided shell, expands and unfolds, tightly filling the space between the braided shell and the vessel wall, achieving rapid blood flow occlusion. Furthermore, even if the filling core collapses in the future, its outer braided shell, as an independent and stable mechanical skeleton, can persistently maintain its original position, ensuring safety.

[0027] This application employs a design of multiple vascular plug units connected in series, allowing the length of each unit to be controlled within 4 mm. By continuously arranging multiple such short units, it is possible to flexibly combine them to achieve the required overall embolization length, ensuring sufficient and reliable blood flow blockage. At the same time, the shorter unit structure also significantly improves the flexibility of the device within the blood vessel, enabling it to better conform to the tortuous vascular anatomy and avoid the vascular wall damage or poor apposition problems that may be caused by a single long rigid embolization body. Thus, while achieving effective embolization, it also improves the safety of the procedure. Attached Figure Description

[0028] The above and other objects, features and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0029] Figure 1 This is a schematic diagram of the structure of a vascular plug assembly;

[0030] Figure 2 These are schematic diagrams of three types of center links;

[0031] Figure 3 This is a schematic diagram of the filling core;

[0032] Figure 4 This is a schematic diagram of the woven shell structure. Detailed Implementation

[0033] The present invention is described below based on embodiments, but the present invention is not limited to these embodiments. In the following detailed description of the present invention, some specific details are described in detail, but well-known methods, processes, procedures, and elements are not described in detail in order to avoid obscuring the essence of the present invention.

[0034] Furthermore, those skilled in the art should understand that the accompanying drawings provided herein are for illustrative purposes only and are not necessarily drawn to scale.

[0035] Unless the context explicitly requires it, the words "comprising," "including," and similar terms throughout the specification and claims should be interpreted as encompassing rather than being exclusive or exhaustive; that is, meaning "including but not limited to."

[0036] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0037] See Figures 1-4The present invention provides a vascular plug assembly, comprising a plurality of vascular plug units connected in series along an axial direction; each vascular plug unit includes: a filling core made of a biocompressible material, a braided shell covering the outside of the filling core, and a central connecting rod axially penetrating the filling core; both ends of the central connecting rod are fixedly connected to the ends of the braided shell, thereby constraining and encapsulating the filling core within the braided shell;

[0038] The woven outer shell is made of shape memory material filaments, allowing the vascular plug unit to be compressed to a first radial dimension, enabling delivery of the vascular plug unit through a sheath.

[0039] After the vascular plug assembly is released from the sheath, the braided outer shell expands to a second radial dimension, causing the braided outer shell to conform to the vessel wall, and driving the filling core to unfold together to form an embolus to block blood flow in the vessel.

[0040] The vascular plug assembly of the present invention is composed of multiple independent vascular plug units connected in series along the axial direction. For example... Figure 1 As shown, a typical vascular plug assembly consists of three such vascular plug units connected in series.

[0041] For each vascular plug unit, it includes:

[0042] The filling core: This part is made of a biocompressible material, such as a cylindrical or olive-shaped open-cell polyurethane foam block. Its function is to expand within the blood vessel to physically fill the space and promote thrombus formation.

[0043] Braided Shell: This part is a tubular mesh structure woven from shape-memory metal wires (such as nickel-titanium alloy wires). It tightly wraps around the outside of the filling core like a cage. To create the braided shell, the filling core is first trimmed, and then metal wires are woven around its outer surface.

[0044] Central connecting rod: This part is a slender metal rod that runs axially through the entire filler core. Both ends of the central connecting rod extend out of the filler core and are securely welded to the ends of the braided outer shell. Through this connection method, the filler core is effectively encapsulated and constrained within the internal cavity formed by the braided outer shell.

[0045] The woven outer shell serves only as a restraining framework, rather than a completely dense metal mesh, so the amount of wire used (reflected in wire diameter and weaving density) can be optimized to the minimum necessary limit. This allows the entire vascular plug unit to be radially compressed to a very small "first radial dimension" (e.g., less than 1.8 mm in diameter), thus enabling it to be easily inserted into a small sheath (less than 2 mm in inner diameter) for delivery.

[0046] Once the vascular plug assembly is ejected from the delivery sheath, its operation proceeds as follows: The braided outer shell, based on its shape memory effect, rapidly expands back to its "second radial dimension" (determined by the vessel's inner diameter), thus adhering to the vessel wall and providing initial anchoring force. Simultaneously, the encapsulated filling core expands under the influence of body fluid and the constraint of the outer shell, rapidly filling the internal space of the braided outer shell to form an effective embolus, ultimately achieving the goal of blocking blood flow to the target vessel.

[0047] Adjacent vascular plug units are connected in series via flexible connectors at the ends of the central connecting rods, allowing the series-connected vascular plug units to conform to the curvature of the blood vessel after deployment. The adjacent vascular plug units are flexibly connected. Specifically, a flexible connector is provided at the end of each central connecting rod. This connection method allows adjacent vascular plug units to move relatively freely within a certain angular range, enabling the entire vascular plug assembly to conform to the natural curvature of the blood vessel like a "chain" when deployed within the vessel, avoiding undue stress on the vessel wall.

[0048] It should be noted that, under natural conditions, the lengths of multiple vascular plug units may be the same or different; the radial dimensions of multiple vascular plug units may be the same or different.

[0049] The flexible connector can be a ball-and-socket joint, a chain-link structure, or a plug-in structure. In the ball-and-socket joint structure, the connecting end of the central link of one vascular plug unit is machined into a ball head, and the corresponding connecting end of an adjacent vascular plug unit is machined into a matching ball-socket joint; the two are then engaged to form a multi-directionally rotatable joint. In another embodiment, a chain-link structure (similar to a necklace link) or a plug-in structure can be used (rotation is achieved through a pin and hole connection). All these structures provide the required flexible hinge functionality.

[0050] Preferably, both ends of the central connecting rod are fixed with contrast rings made of platinum-iridium alloy, which protrude from the filling core. These contrast rings are preferably made of platinum-iridium alloy (a material with high X-ray impermeability). The contrast rings are fixed to the ends of the central connecting rod, and their position is designed so that they protrude from the filling core. In this way, under X-ray fluoroscopy, the surgeon can clearly see the contrast points at both ends of each vascular plug unit, thereby accurately determining the position, deployment shape, and connection status between units, achieving precise intraoperative positioning and release.

[0051] Preferably, the woven shell is made of 8 to 24 shape memory material filaments woven in a cross-hatching manner. For example, 16 nickel-titanium alloy wires are used. The preferred weaving method is a cross-hatching weave (e.g., a 1-over-1-under plain weave), which can form a uniform and stable mesh-like tubular structure, ensuring sufficient radial support while also having good flexibility and compressibility.

[0052] Preferably, the shape memory material filament is selected from one or more of nickel-titanium alloy filament, polydioxanone filament, polyetheretherketone filament, or polyetherketone filament.

[0053] Preferably, the filling core is made of polyurethane foam, and the diameter of the filling core in its unfolded state is 1.2 to 2 times the maximum diameter of the braided outer shell. For example, if the free diameter of the braided outer shell is 5 mm, the free diameter of the filling core can be designed to be 6 mm to 10 mm. This dimensional relationship ensures that the filling core is in a "pre-compressed" state after being inserted into the shell. Upon release in vivo, the core has a strong tendency to expand outward, thereby adhering more tightly to the blood vessel wall and enhancing the immediate occlusion effect.

[0054] Preferably, the filling core is prepared by the following steps:

[0055] S100. The polyurethane foam matrix is ​​immersed in a solution containing the drug, and the drug is carried inside and on the outer surface of the polyurethane foam after curing to obtain a drug matrix; the drug is a procoagulant or antifibrinolytic drug, and the drug is one or more of vitamin K, tranexamic acid, oxidized cellulose, and aminocaproic acid.

[0056] After soaking for a sufficient time, the material is cured by heating or light, so that the drug is stably attached to the internal pores and outer surface of the polyurethane foam, thus obtaining the drug matrix.

[0057] S200. A hydrophilic coating solution is sprayed onto the outer surface of the drug matrix to form a hydrophilic lubricating coating on the outer surface of the drug matrix.

[0058] After the hydrophilic coating solution cures, a smooth, hydrophilic lubricating coating is formed on the surface of the drug matrix. This coating significantly reduces the frictional resistance of the vascular plug assembly within the sheath, improves the push feel, and accelerates blood infiltration into the core surface, synergistically promoting rapid thrombus formation with the internal drug.

[0059] The hydrophilic coating solution comprises resin, photoinitiator, dispersant, and solvent, with a mass ratio of 2-6:0.1-1:0.1-1:92-97.8.

[0060] The resin is one or more of polyurethane acrylate, polyester acrylate, polyether acrylate, silicone acrylate, and epoxy acrylate resin;

[0061] The photoinitiator is one or more of Irgacure 819, Irgacure 2959, Irgacure 1173, TPO, and BAPO; used to initiate resin curing under ultraviolet light irradiation.

[0062] The dispersant is one or more of polyether-modified silicone oil, acrylate-modified silicone oil, acrylate copolymer, and polyoxyethylene ether; it is used to ensure the uniformity and coating effect of the hydrophilic coating solution.

[0063] The solvent is one or more selected from water, methanol, ethanol, isopropanol, n-butanol, butanone, ethyl acetate, butyl acetate, cyclohexane, and n-hexane.

[0064] Untreated polyurethane foam, due to its porous structure and the resulting microscopically rough surface after cutting, generates significant frictional resistance when passing through a narrow sheath, leading to a stiff and laborious pushing experience, and potentially causing surface wear or jamming. This application addresses this by constructing a uniform hydrophilic lubricating coating on the polyurethane foam surface to obtain the filling core. During delivery, the hydrophilic lubricating coating forms a smooth interface upon contact with blood or saline solution, significantly reducing the resistance as the filling core moves within the sheath. Furthermore, the surgeon experiences smoother and more controllable delivery force feedback when operating the pusher, improving the precision and controllability of the surgical procedure.

[0065] The drug solution includes coagulant, initiator, resin, dispersant and solvent, with the following mass ratio: coagulant: initiator: resin: dispersant: solvent = (3-10) : (0.1-2) : (1-5) : (0.1-1) : (82-95.8).

[0066] in,

[0067] The coagulant is one or more of the following: kaolin, montmorillonite, thrombin, fibrinogen, batroxobin, platelet-rich material, collagen, chitosan, carboxymethyl chitosan, polylysine, and sodium alginate.

[0068] The initiator is one or more of the following: azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, benzoyl peroxide, potassium persulfate, sodium bisulfite, methyl p-toluenesulfonate, methyl ethyl ketone peroxide, diphenyliodonium hexafluorophosphate, mercaptoethanol, n-dodecyl mercaptoethanol, pentaerythritol tetra(3-mercaptopropionate), N,N-dimethylcyclohexylamine, and triethylamine.

[0069] The resin is one or more of epoxy resin, acrylic resin, amino resin, and polyester resin.

[0070] The dispersant is one or more of the following: polyether-modified silicone oil, acrylate-modified silicone oil, acrylate copolymer, polyoxyethylene ether, and polyethylene glycol ester.

[0071] The solvent is one or more of the following: water, methanol, ethanol, isopropanol, n-butanol, butanone, ethyl acetate, butyl acetate, cyclohexane, n-hexane, and acetic acid.

[0072] Step S100 is as follows:

[0073] Completely immerse the clean, dry polyurethane foam matrix in the prepared drug solution, ensuring the solution fully wets all pores of the foam. The immersion time is preferably 10-30 minutes. After immersion, remove the polyurethane foam matrix and gently squeeze to remove excess drug solution. Then, transfer it to an oven at 60-80°C for heat curing, with a curing time of 30-120 minutes. This process cross-links and cures the resin, firmly fixing the curing agent to the interior and exterior surfaces of the polyurethane foam matrix.

[0074] After thermosetting, the polyurethane foam matrix is ​​repeatedly squeezed and cleaned with deionized water to remove unreacted residual components. Finally, the cleaned polyurethane foam matrix is ​​dried in a low-temperature vacuum drying oven at 45°C to obtain a drug matrix with a coagulating drug coating on both the interior and surface.

[0075] It should be understood that the above embodiments are merely exemplary and not restrictive. Various obvious or equivalent modifications or substitutions that can be made by those skilled in the art regarding the above details without departing from the basic principles of the present invention will be included within the scope of the claims of the present invention.

Claims

1. A vascular plug assembly, comprising: The vascular plug unit comprises a filling core made of biocompressible material, a woven shell wrapped outside the filling core, and a central link penetrating through the filling core in the axial direction; the two ends of the central link are fixedly connected with the end of the woven shell, so as to constrain and encapsulate the filling core in the woven shell; The woven shell is woven by shape memory material wires, so that the vascular plug unit can be compressed to a first radial size, so that the vascular plug unit can be transported through a sheath tube, After the vascular plug assembly is released from the sheath tube, the woven shell self-expands to a second radial size, so that the woven shell is in close contact with the blood vessel wall, and the filling core is expanded together to form a plug body to block the blood flow of the blood vessel.

2. The vaso-occlusive assembly of claim 1, wherein, The adjacent vascular plug units are connected in series through the flexible connecting joints at the ends of the central link, so that the series-connected vascular plug units can conform to the curved direction of the blood vessel after expansion.

3. The vaso-occlusive assembly of claim 2, wherein, The flexible connecting joint is a matching structure of ball head and ball socket, a chain structure or a plug-in structure.

4. The vaso-occlusive assembly of any of claims 1-3, wherein, The two ends of the central link are fixedly connected with the developing ring made of platinum-iridium alloy, and the developing ring is exposed to the filling core.

5. The vaso-occlusive assembly of any of claims 1-3, wherein, The woven shell is woven by 8 to 24 shape memory material wires in a crosswise manner.

6. The vaso-occlusive assembly of claim 5, wherein, The shape memory material wire is selected from one or more of a nickel-titanium alloy wire, a polydioxanone wire, a polyether ether ketone wire or a polyether ketone ketone wire.

7. The vaso-occlusive assembly of claim 1, wherein, The filling core is made of polyurethane foam, and the diameter of the filling core in the expanded state is 1.2 to 2 times the maximum diameter of the woven shell.

8. The vaso-occlusive assembly of claim 7, wherein, The filling core is prepared by the following steps: S100, immerse the polyurethane foam base in a solution containing a drug, and after curing, carry the drug on the inside and outside surface of the polyurethane foam to obtain a drug base; the drug is a procoagulant drug or an antifibrinolytic drug, and the drug is one or more of vitamin K, tranexamic acid, oxidized cellulose, and aminocaproic acid; S200, spray a hydrophilic coating solution on the outer surface of the drug base to form a hydrophilic lubricating coating on the outer surface of the drug base.

9. The vaso-occlusive assembly of claim 8, wherein, The hydrophilic coating solution is resin, photoinitiator, dispersant and solvent, and the mass ratio between them is 2-6:0.1-1:0.1-1:92-97.

8.

10. The vaso-occlusive assembly of claim 9, wherein, The resin is one or more of polyurethane acrylate, polyester acrylate, polyether acrylate, silicone acrylate, and epoxy acrylate resin; The photoinitiator is one or more of Irgacure 819, Irgacure 2959, Irgacure 1173, TPO, and BAPO; The dispersant is one or more of polyether-modified silicone oil, acrylate-modified silicone oil, acrylate copolymer, and polyoxyethylene ether; The solvent is one or more of water, methanol, ethanol, isopropanol, n-butanol, butanone, ethyl acetate, butyl acetate, cyclohexane, and n-hexane.

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