Cutting and weaving covered stent
By employing a multi-layered structural design involving a cut skeleton, braided mesh, and ePTFE membrane, the problem of plaque detachment and restenosis during the expansion of metal stents was solved, achieving stent stability and flexibility and preventing microembolism and vascular restenosis.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-23
- Publication Date
- 2026-04-03
AI Technical Summary
Existing metal stents are prone to plaque detachment during expansion, leading to vascular embolism, and insufficient radial support can easily cause in-stent restenosis.
The design combines a cut skeleton and a woven mesh, with an outer layer covered by an ePTFE membrane and drug-coated inner and outer layers, forming a multi-layered structure to provide good support and flexibility while preventing plaque detachment and restenosis.
It effectively prevents microembolism caused by plaque detachment, inhibits vascular smooth muscle proliferation, prevents vascular restenosis, and ensures the stability and flexibility of the stent.
Smart Images
Figure CN224070646U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of medical device technology, specifically relating to a cut and braided covered stent. Background Technology
[0002] Narrowing of blood vessels severely restricts blood flow and promotes thrombus formation, leading to myocardial infarction or stroke. The most common site of narrowing is the carotid artery. To improve carotid artery stenosis, laser-cut or braided metal stents are usually placed. The stent is typically implanted into the blood vessel in a compressed state, and once it reaches the narrowed area, its expansion opens the lumen of the blood vessel.
[0003] As the stent expands, it comes into contact with relatively fragile plaques in the surrounding carotid artery tissue. Traditional carotid stent structures have large gaps, and the expanded stent can cause the plaque to rupture, producing fragments. These fragments can enter the bloodstream and flow to small intracranial blood vessels, leading to a stroke.
[0004] While mesh-woven metal stents can effectively prevent detached plaques from passing through the stent's mesh and entering the blood vessel lumen, their radial support is insufficient, making them prone to in-stent restenosis later on.
[0005] The following problems exist: 1. Most existing metal stents are manufactured using laser cutting or mesh braiding technology. The mesh of the cut stent is relatively large, which can easily cause vascular embolism after plaque detachment. If the mesh size of the stent is reduced, the radial support force of the stent will increase significantly, which will inevitably damage the vascular intima.
[0006] 2. Single braided stents have smaller mesh sizes, which can effectively prevent detached plaques from passing through the stent mesh and entering the blood vessel lumen. However, their radial support is insufficient, which can easily lead to in-stent restenosis in the later stages.
[0007] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Utility Model Content
[0008] The purpose of this invention is to provide a cut braided covered stent to solve the problem that the mesh size of a single cut stent is relatively large, which can easily cause vascular embolism after plaque detachment. If the mesh size of the stent is reduced, the radial support force of the stent will increase significantly, which will inevitably damage the vascular intima.
[0009] To achieve the above objectives, this utility model provides the following technical solution:
[0010] A cut-and-woven film-coated scaffold includes a cut frame, a woven mesh, and an ePTFE membrane. The cut frame is designed with a combination of open and closed loops, and the two ends of the scaffold have good anchoring effect in the body. The middle part is an open-loop structure, which, through the support of the woven mesh, makes the whole structure both supportive and flexible.
[0011] Preferably, the support has a multi-layer structure with two or more layers. From the outside to the inside, the support consists of a braided layer and a cut layer. The braided layer and the cut layer are not interwoven and can be separated from each other. There is no strong connection between them.
[0012] Preferably, the woven layer is made of fine filaments, densely woven, with a high metal coverage rate of 20% to 40%.
[0013] Preferably, the scaffold consists of, from the outside to the inside, a polymer film layer, a braided layer, and a cut layer. The polymer film layer and the braided layer have a strong bonding point and cannot be separated. The braided layer and the cut layer scaffold do not interweave and can be separated from each other, and there are no strong bonding sites between them.
[0014] Preferably, the polymer film can be ePTFE, PET, PA, or other materials.
[0015] Preferably, the scaffold consists of, from the outside in, a coating layer, a polymer film layer, a braided layer, and a cutting layer. The coating layer is attached to the polymer film layer. There is a strong bond between the polymer film layer and the braided layer, and the two cannot be separated. The braided layer and the cutting layer scaffold are not interwoven and can be separated from each other. There is no strong bond between the two.
[0016] Preferably, the coating can be a hydrophilic coating, a biomimetic coating that inhibits thrombus formation, or a drug coating that inhibits cell endothelialization. The drug can be paclitaxel, rapamycin, etc.
[0017] Beneficial effects:
[0018] (1) This utility model is composed of a cutting skeleton, a woven mesh and an ePTFE membrane. The cutting skeleton is designed with a combination of open and closed loops. The two ends of the support have a good anchoring effect in the body. The middle is an open loop structure. With the support of the woven mesh, the whole structure has both good support and flexibility.
[0019] (2) The outer layer of this utility model is covered with an ePTFE membrane, which has a larger coverage area for the plaque and can effectively reduce the probability of the plaque falling off from the mesh of the support and prevent microembolism after the plaque falls off.
[0020] (3) The ePTFE membrane of the inner and outer layers of this utility model is coated with a drug-loaded coating, which can resist thrombosis, inhibit the proliferation of vascular smooth muscle, and prevent intravascular restenosis.
[0021] (4) By coating the inner and outer layers, the cutting skeleton, the woven mesh, and the ePTFE membrane coating are integrated to prevent the woven mesh from shifting and failing, and the inner and outer layers of the support from delaminating, which would cause restenosis. Attached Figure Description
[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. Wherein:
[0023] Figure 1 This is a schematic diagram of the double-layer bracket of this utility model;
[0024] Figure 2 This is a schematic diagram of the self-expanding support for cutting according to this utility model;
[0025] Figure 3 This is a schematic diagram of the overall structure of the bracket of this utility model;
[0026] Figure 4 This is a schematic diagram of the cutting skeleton of this utility model;
[0027] Figure 5 This is a schematic diagram of the circumferential braided yarn of this utility model;
[0028] Figure 6 This is a schematic diagram of the axial braided yarn of this utility model.
[0029] In the diagram: 1. Cutting skeleton; 2. Woven mesh; 3. ePTFE membrane coating; 4. Circumferential braided yarn; 5. Axial braided yarn. Detailed Implementation
[0030] The technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art are within the protection scope of this utility model.
[0031] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0032] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.
[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" and "second" may explicitly or implicitly include one or more features.
[0034] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, it can be a fixed connection or a movable connection, a detachable connection or a non-detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection or a connection that can communicate with each other; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two elements, an indirect connection, or an interaction between two elements.
[0035] In the description of this utility model, "distal end" refers to the end that is farther away from the doctor during surgery, and "proximal end" refers to the end that is closer to the doctor during surgery.
[0036] The present invention will now be described in detail with reference to the embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.
[0037] This invention addresses the issue that existing metal stents are mostly manufactured using laser cutting or mesh weaving techniques. The mesh size of the cut stent is relatively large, which can easily lead to vascular embolism after plaque detachment. If the mesh size of the stent is reduced, the radial support force of the stent will increase significantly, which will inevitably damage the vascular intima.
[0038] The present invention provides a detailed description of a cut-and-woven film-coated bracket through specific embodiments below.
[0039] Example 1
[0040] This embodiment provides a cut-woven coated support structure, which is made of... Figure 1 As shown, a double-layer stent system is used, consisting of an inner layer of self-expanding stent and an outer layer of densely woven stent, to address the problems of plaque detachment and restenosis at the narrowing of the densely woven stent.
[0041] Depend on Figure 2As shown, the self-expanding stent is laser-cut from alloy tubing. The alloy tubing can be made of nickel-titanium alloy, stainless steel, or biodegradable magnesium alloy, iron alloy, zinc-based alloy, etc. The stent features a closed-loop design at both ends, with flared ends and imaging mounting points to facilitate intraoperative observation of the stent's position and status. After release, the stent's ends provide excellent anchorage within the body. The middle section has an open-loop design, with only two staggered connecting beams between the upper and lower loops, providing good flexibility and support. Each loop contains 12 or more V-shaped rods; the open-loop arc angle ∠1 is 45-65°, and the closed-loop arc angle ∠2 is 20-35°. The connecting beam width can be 0.25mm, and the length of the rods at both ends is three times that of the middle rod. The self-expanding stent utilizes a combination of closed-loop and open-loop design to provide excellent flexibility and support.
[0042] The braided support is made of braided filaments with a diameter of 0.03mm-0.05mm. The braided filaments are platinum core nickel-titanium wire (DFT wire). Because the inner platinum core has the property of being non-transparent, the braided mesh can be developed in its entirety, which makes it easy to cut the support of the self-expanding support.
[0043] The DFT wire is a tubular support formed by axial and radial interlacing and cyclically wrapping around each other from one end to the other, with the mesh area of the woven support ranging from 0.3 m² to 0.6 mm². Figure 1 The braided mesh support is shown.
[0044] The braided stent has a smaller mesh size, which can effectively prevent detached plaques from passing through the stent mesh and entering the blood vessel lumen on the outer layer. The self-expanding cut stent on the inner layer provides good support and solves the problem of narrowing of the dense mesh.
[0045] Example 2
[0046] like Figure 3 As shown, the integrated cutting-braiding film-coated support structure consists of a cutting skeleton 1, a braided mesh 2, and an ePTFE membrane coating 3. The cutting skeleton combines open-loop and closed-loop designs; the braided mesh is nested on the open-loop skeleton; the ePTFE membrane has a microporous structure and is dip-coated with an inner and outer layer.
[0047] like Figure 4As shown, the cutting skeleton 1 is laser-cut from alloy tubing. The alloy tubing can be made of nickel-titanium alloy, stainless steel, or biodegradable magnesium alloy, iron alloy, zinc-based alloy, etc. The skeleton has a closed-loop design at both ends, with flared ends and imaging mounting points to facilitate intraoperative observation of the stent's position and status. After release, the stent's ends have good anchoring within the body. The middle section has an open-loop design, with only two connecting beams between the upper and lower loops, and these beams are staggered. Each loop has 12 or more V-shaped rods; the open-loop arc angle ∠1 is 45-65°, and the closed-loop arc angle ∠2 is 20-35°. The width of the connecting beams can be 0.25mm, and the length of the rods at both ends is three times the length of the middle rod.
[0048] The woven mesh 2 is hand-woven based on the cut frame 1. The circumferential weaving wires 4 enter from one side of the V-shaped rod of the cut frame 1 and exit from the other side, extending circumferentially around the frame. The beginning and end of the circumferential weaving wires are fixed to the side of the V-shaped rod by welding. Figure 5 As shown. The axial braided wire 5 enters from a crest or trough of the cutting skeleton 1 and exits from the crest or trough of the next cycle, extending axially and passing through the beginning and end of the cutting skeleton 1. The head and tail ends of the axial braided wire are fixed to the inner side of the crest or trough by welding, as shown. Figure 6 As shown. The weaving is performed sequentially in the manner described above, ultimately forming woven net 2.
[0049] The ePTFE membrane coating consists of three layers, inner and outer, made of 0.01mm thick tubing with a density of 0.5±0.15g / cc. These layers undergo a 20-minute heat fusion treatment at 425℃ under argon protection. This process integrates the cut skeleton, woven mesh, and ePTFE membrane coating into a single unit. The ePTFE membrane's microporous structure allows for the impregnation of macrocyclic antibiotics or heparin coatings, thereby preventing thrombosis, inhibiting vascular smooth muscle proliferation, and preventing restenosis.
[0050] In summary:
[0051] This invention utilizes a stent composed of a cutting framework 1, a braided mesh 2, and an ePTFE membrane. The cutting framework 1 features a combination of open and closed-loop designs, providing excellent anchoring at both ends within the body. The middle section is an open-loop structure, supported by the braided mesh 2, offering both good support and flexibility. The outer layer is covered with an ePTFE membrane, providing greater plaque coverage and effectively reducing the probability of plaque detachment from the stent mesh, preventing microembolism after plaque detachment. Both inner and outer ePTFE membranes are coated with a drug-eluting coating, which has anti-thrombotic properties, inhibits vascular smooth muscle proliferation, and prevents intravascular restenosis. The inner and outer membranes form a unified structure, preventing displacement and failure of the braided mesh 2, and preventing delamination of the stent layers, which could lead to restenosis.
[0052] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A cut braided covered stent, characterized by, It comprises a cutting framework, a woven net and a polymer film arranged in sequence from inside to outside, the cutting framework is a combination of open loop and closed loop, the two ends of the framework are designed as closed loop structure, which has good anchoring effect in the body; the middle part is designed as open loop structure, the support of the woven net makes the whole have good support and softness at the same time. The polymer film is made of polymer or PET or PA material.
2. The cut braided covered stent of claim 1, wherein, The woven net is made of fine wires and has high metal coverage, the metal coverage is up to 20%~40%.
3. The cut braided covered stent of claim 1, wherein, There are firm bonding points between the polymer film and the woven net, they cannot be separated, the woven net and the cutting framework are not interwoven and can be separated, and there are no firm bonding points between them.
4. The cut stent graft of claim 1, wherein, A coating is arranged on the outer side of the polymer film.
5. The cut stent graft of claim 4, wherein, The coating can be a hydrophilic coating, a biomimetic coating for inhibiting thrombosis, or a drug coating for inhibiting endothelialization, and the drug can be paclitaxel or rapamycin.