Intravascular stent for preventing occlusion of branch vessels and method for manufacturing the same

Abstract

This invention discloses an endovascular stent for preventing branch vessel occlusion. The stent includes a proximal end, a distal end, and a mid-section. The stent is a mesh-like structure formed by weaving multiple biocompatible braided filaments with one or more high-density metal wires. The number of filaments in the proximal and distal ends is less than that in the mid-section, and the mesh size in the proximal and distal ends is larger than that in the mid-section. This endovascular stent provides sufficient support while effectively reducing the risk of branch vessel occlusion. The stent is also easier to press into a smaller diameter stent delivery tube, and the filaments at both ends are less prone to tangling during stent deployment.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to an endovascular stent that can treat vascular stenosis. Background Technology

[0002] Cerebrovascular disease is a major threat to human health today and is the leading cause of death in my country. For example... Figure 1 As shown, atherosclerosis is the main cause of stenosis in the cerebral and carotid arteries. Given the extremely high risks of surgery, interventional treatment involving the placement of vascular stents via catheter is the preferred option. Figure 2 This is a schematic diagram of carotid artery stent deployment. Current intracranial stents used clinically to treat cerebral vascular stenosis have the following major drawbacks: 1) The stent material is a non-degradable metal, making it highly thrombogenic. Patients must take antiplatelet or anticoagulant drugs long-term, but the risk of cerebral hemorrhage is high when taking dual antiplatelet drugs; 2) Numerous clinical reports indicate that branch vessel occlusion has occurred in many cases when using cerebral vascular stents, leading to complications of varying degrees, some of which can be life-threatening; 3) When braided stents use many metal wires, multiple wires often become entangled at both ends of the stent during deployment, posing a significant challenge to the procedure and posing a substantial risk to the patient. Summary of the Invention

[0003] This invention proposes an endovascular stent that prevents branch vessel blockage and entanglement of the stent's two ends. It comprises a mesh-like stent woven from multiple biocompatible braided filaments and one or more high-density metal wires. The number of filaments at both ends of the stent is less than the number of filaments in the middle section, and the mesh size in the middle section is smaller than or equal to the mesh size at both ends. Furthermore, the braided filaments are biodegradable metal wires or biodegradable polymer filaments. The composite structure endovascular stent of this invention effectively solves many problems of existing products: 1) Compared to existing clinically used vascular stents, the stent body of this invention is biodegradable, eliminating the need for long-term antiplatelet medication for patients; 2) The large mesh size at both ends of the stent makes it less prone to blocking branch vessels; 3) The fewer filaments at both ends make it easier to press-fit into small-diameter catheters, and the filaments are less likely to entangle during stent release. Existing vascular stents cannot simultaneously meet all of these characteristics. Attached Figure Description

[0004] Figure 1 Schematic diagram of atherosclerosis Figure 2 Schematic diagram of carotid artery stent deployment Figure 3 This is a schematic diagram of an intravascular stent according to Embodiment 1 of the present invention. Figure 4 This is a schematic diagram of the endovascular stent in Embodiment 2 of the present invention. Figure 5This is a schematic diagram of the endovascular stent in Embodiment 3 of the present invention. In the diagram: 1. Proximal end of the stent; 2. Mid-section of the stent; 3. Distal end of the stent. Detailed Implementation

[0005] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0006] Example 1 The main body of this embodiment consists of 30 magnesium alloy wires, mixed with two platinum-iridium alloy wires, each with a diameter of 0.02 mm. After fixing the 30 spools of magnesium alloy wire and the two spools of platinum-iridium alloy wire onto the braiding machine, a stainless steel tube with an outer diameter of 3 mm, an inner diameter of 2 mm, and a length of 1 m is used as the braiding mandrel. The mandrel is fixed to the braiding machine, and an 80-90 cm long braided mesh tube is prepared at a mesh count of 75-100 meshes per inch and a rotation speed of 70-180 r / min. After the braided mesh tube is wound and fixed with stainless steel wire, the braiding mandrel with the braided mesh tube is removed and shaped. After shaped, the braided mesh tube is cut to 4 cm. The magnesium alloy wires at both ends of the support are shortened by 5 mm every other wire, and then the shortened wires are welded together in pairs to obtain the desired shape. Figure 3 The stent shown has 17 wires at both ends and 32 wires in the middle. In this embodiment, the stent has a diameter of 3mm in its natural state (i.e., fully deployed) and a middle section length of 3cm, making it suitable for treating vascular lesions with stenosis lengths of 25-28mm. The dense, small-mesh middle section of the stent provides sufficient radial support, while the sparse, large-mesh ends prevent the wires from tangling during stent deployment, significantly reducing the risk of branch vessel occlusion.

[0007] Example 2 The main body of this embodiment consists of 28 polylactic acid (PLLA) filaments, mixed with 4 tantalum filaments, all with a diameter of 0.03 mm. The 28 spools of PLLA filaments and the 4 spools of tantalum filaments are fixed to the braiding machine. A stainless steel tube with an outer diameter of 3 mm, an inner diameter of 2 mm, and a length of 1 m is used as the braiding mandrel. The mandrel is fixed to the braiding machine, and a braided mesh tube of 80-90 cm in length is prepared at a mesh count of 75-100 meshes per inch and a rotation speed of 70-180 r / min. After the braided mesh tube is wound and fixed with stainless steel wire, the braiding mandrel with the mesh tube is removed and shaped. After shaping, the braided mesh tube is cut to 30 mm. Every other PLLA filament at both ends of the support is shortened by 5 mm, and then the shortened filaments at the far end of the support are riveted together in pairs. This yields the desired result. Figure 4The stent shown has 18 wires at both ends and 32 wires in the middle. In this embodiment, the stent has a diameter of 3mm in its natural state (i.e., fully deployed state) and a middle section length of 20mm, making it suitable for treating lesions with stenosis lengths of 15-18mm. The dense, small-mesh middle section of the stent provides sufficient radial support, while the sparse, large-mesh ends prevent the wires from tangling during stent deployment, significantly reducing the risk of branch vessel occlusion.

[0008] Example 3 The main body of this embodiment consists of 32 nickel-titanium alloy wires, mixed with 2 platinum-iridium alloy wires, all with a diameter of 0.02 mm. After fixing the 32 spools of nickel-titanium alloy wires and 4 spools of platinum-iridium alloy wires onto the braiding machine, a stainless steel tube with an outer diameter of 4 mm, an inner diameter of 3 mm, and a length of 1 m is used as the braiding mandrel. The mandrel is fixed onto the braiding machine, and a braided mesh tube 80-90 cm long is prepared at a mesh count of 75-100 meshes per inch and a rotation speed of 70-180 r / min. After the braided mesh tube is wound and fixed with stainless steel wire, the braiding mandrel with the mesh tube is removed and shaped. After shaped, the braided mesh tube is cut to 35 mm. Every other nickel-titanium alloy wire at both ends of the support is shortened by 5 mm, resulting in an open, unconnected structure between the braided wires at both ends of the support, thus obtaining the desired shape. Figure 5 The stent shown has 17 wires at both ends and 32 wires in the middle. In this embodiment, the stent has a diameter of 4 mm in its natural state (i.e., fully deployed state) and a middle section length of 25 mm, making it suitable for treating lesions with stenosis lengths of 20-22 mm. The dense, small-mesh middle section of the stent provides sufficient radial support, while the sparse, large-mesh ends prevent the wires from tangling during stent deployment, significantly reducing the risk of branch vessel occlusion.

[0009] The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention; it is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the present invention. The endovascular stent of the present invention can be applied to many clinical occasions, such as intracranial vascular stents, carotid artery stents, vertebral artery stents, renal artery stents, iliac artery stents, iliac vein stents, cross-knee vascular stents, lower limb vascular stents, etc.

Claims

1. An endovascular stent for preventing branch vessel blockage, characterized in that: It includes a mesh-like scaffold made of multiple biocompatible braided filaments and one or more high-density metal wires; the filaments are interwoven or back-and-forth in a spiral feeding manner along the axial direction, and two intersecting braided filaments can slide freely at the nodes; the braided filaments at both ends of the mesh-like scaffold are in an unconnected open structure or a closed structure fixed in pairs.

2. The endovascular stent for preventing branch vessel blockage as described in claim 1, characterized in that: The diameter of the braided filaments and high-density metal wires ranges from 10 micrometers to 200 micrometers.

3. The endovascular stent for preventing branch vessel blockage as described in claim 1, characterized in that: The cross-sectional shapes of the braided wires and high-density metal wires include, but are not limited to, circles, ellipses, and rectangles.

4. The endovascular stent for preventing branch vessel blockage according to claim 1, characterized in that: The stent consists of the proximal end, the distal end, and the mid-section. The number of wires in the proximal and distal ends is less than the number of wires in the mid-section.

5. The endovascular stent for preventing branch vessel blockage according to claim 1, characterized in that: The mesh size in the middle section of the tubular support is smaller than or equal to the mesh size at both ends of the support.

6. The endovascular stent for preventing branch vessel blockage according to claim 1, characterized in that... The braided yarn material includes one or more of the following: nickel-titanium alloy, cobalt-chromium alloy, magnesium alloy, zinc alloy, iron-based alloy, molybdenum alloy, polyglycolic acid, polylactic acid, polyglycolic acid-lactide, polycaprolactone, polyglycolic acid, poly-L-glutamic acid, polyaspartic acid, and polydioxanone.

7. The endovascular stent for preventing branch vessel blockage according to claim 1, characterized in that... The surfaces of the braided filaments and high-density metal wires are coated with a polymer film. The film is made of one or more biodegradable or non-biodegradable polymer materials, including polyglycolic acid, polylactic acid, polyglycolic acid-lactide, polycaprolactone, polyglycolic acid, poly-L-glutamic acid, polyaspartic acid, polydioxanone, polyurethane, silicone, etc.

8. The endovascular stent for preventing branch vessel blockage according to claim 1, characterized in that... The surface and film layer of the braided filaments and high-density metal wires can be loaded with therapeutic drugs, including one or more of antiplatelet drugs, anticoagulants, anti-inflammatory drugs, antibacterial drugs, and endothelialization-promoting drugs.

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