Flow diversion embolization stent

Abstract

The application discloses a blood flow guiding embolism stent, which comprises a stent body, the stent body is an integrated structure which is interlaced by at least two kinds of metal wires with different hardness, the stent body comprises a single-layer area and a layered area, the layered area is arranged on at least one end of the single-layer area, the interlacing density of the single-layer area is greater than that of the layered area, the layered area is at least two net body structures which are gradually separated and interlaced from the single-layer area, the hardness of each layer of the net body structure gradually decreases from outside to the center of the stent body, the outermost net body structure is an anchoring support part, and the remaining net body structures of the layered area are blood flow passage establishing parts. Compared with the prior art, the stent body has better flexibility and passability, the stent body is divided into the single-layer area and the layered area with different interlacing densities, the layered area can avoid collateral vessels, and the single-layer area can cover an aneurysm, so that the intracranial aneurysm can be effectively treated, and the treatment effect is improved.

Description

Technical Field

[0001] This invention relates to a medical device, and more particularly to a blood flow diversion embolization stent. Background Technology

[0002] Intracranial aneurysms are abnormally bulging cavities formed on the walls of intracranial arteries. Their thin walls pose a risk of rupture under continuous blood flow, making them a major cause of subarachnoid hemorrhage, accompanied by a certain rate of disability and mortality. Treatment methods for intracranial aneurysms typically include open craniotomy and endovascular interventional procedures.

[0003] However, traditional open craniotomy clipping surgery carries significant risks of trauma, and the procedure is complex and challenging. Interventional vascular surgery includes coil embolization and dense mesh stent implantation. Coil embolization requires filling the aneurysm with metal coils; improper operation can damage the thin-walled aneurysm, leading to the risk of acute aneurysm rupture. Furthermore, implanted coils also carry the risk of dislodgement (falling out of the aneurysm). If the aneurysm neck is large, one or more additional stents may be needed to plug the coils, a method that is cumbersome and costly. Dense mesh stents, as a novel interventional treatment method, offer certain advantages. They are typically made of woven metal wires with a high metal coverage density and few gaps, effectively reducing or blocking blood flow into the aneurysm and promoting healing of the aneurysm neck.

[0004] Dense-mesh stents have demonstrated good therapeutic effects in treating common aneurysms. However, current dense-mesh stents still have certain limitations:

[0005] 1. It is woven from very fine metal wires, which results in insufficient support for the stent, making it prone to collapse or deformation, and may also lead to the stent not being able to be opened.

[0006] 2. The stent has high rigidity and poor bending ability, which will cause continuous pressure on the blood vessels both during and after implantation, and is prone to damage to the blood vessels.

[0007] 3. Poor positioning ability: If the stent does not have a certain anchoring ability during the release process, it will increase the difficulty of the operation and the failure rate. Even if the operation is successful, there is a risk of stent slippage or displacement after implantation.

[0008] 4. A mesh tube woven from multiple strands of metal wires has a high metal density. In addition to blocking the aneurysm at the lesion site, it may also block the collateral vessels, thus causing a series of complications.

[0009] 5. Stents with poor flexibility have poor compliance and cannot conform well to the tortuous blood vessel course after deployment, resulting in insufficient stent apposition to the vessel wall, forming gaps, causing thrombosis, promoting vascular stenosis, or in-stent occlusion, etc.

[0010] 6. Poor permeability: Poor permeability can lead to damage to the stent during delivery within the catheter, or prevent it from reaching the lesion and achieving the therapeutic goal. Summary of the Invention

[0011] The purpose of this invention is to provide a blood flow guiding embolization stent. The technical problem to be solved is to improve the support anchoring force and wall adhesion performance of the dense mesh stent while providing better flexibility and permeability, so as to achieve more effective treatment of intracranial aneurysms.

[0012] To solve the above problems, the present invention adopts the following technical solution: a blood flow guiding embolization stent, comprising a stent body, wherein the stent body is an integral structure woven from at least two kinds of metal wires of different hardnesses. The stent body includes a single-layer region and a layered region. The layered region is at least located at one end of the single-layer region. The weaving density of the single-layer region is greater than the weaving density of the layered region. The layered region is a mesh structure of at least two layers gradually separated and woven from the single-layer region. The hardness of each layer of the mesh structure decreases sequentially from the outside to the center of the stent body. The outermost mesh structure is an anchoring support part, and the remaining mesh structures of the layered region are blood flow channel establishment parts, which also play a role in auxiliary support and protection.

[0013] Furthermore, the weaving density of the outermost mesh structure is less than the weaving density of the remaining mesh structures in the layered region.

[0014] Furthermore, the layered area has two layers, namely an outer layer and an inner layer. The hardness of the outer layer is greater than that of the inner layer, and the weaving density of the outer layer is less than that of the inner layer.

[0015] Furthermore, the longitudinal section of the outer layer is tapered or a variable-diameter circular tube, with its maximum diameter being greater than the outer diameter of the support body.

[0016] Furthermore, the metal wire is made of one or more of stainless steel, nickel-titanium alloy, cobalt-chromium alloy, platinum, iridium, and tungsten.

[0017] Furthermore, the cross-section of the metal wire is at least one of a circle, an ellipse, or a polygon.

[0018] Furthermore, the polygon is a rectangle, a square, or a triangle.

[0019] Furthermore, the outer layer has a wire diameter of 0.0005”-0.004”, and the inner layer 32 has a wire diameter of 0.0001”-0.003”.

[0020] Furthermore, the outer layer and the inner layer have equal lengths, the outer layer has a shorter length than the inner layer, or the outer layer has a longer length than the inner layer.

[0021] Furthermore, the layered regions are symmetrically arranged at both ends of the single-layer region.

[0022] Compared with existing technologies, this invention uses an integrated structure woven from at least two types of metal wires with different hardness to make the stent body more flexible and passable. The stent body is divided into single-layer and multi-layer areas with different weaving densities. The hardness of the multi-layer area gradually decreases from the outside to the center of the stent body, so that the outermost mesh structure has an anchoring and supporting function, while the remaining mesh structures are used to maintain blood flow and achieve drainage. The multi-layer area can avoid paravascular vessels, while the single-layer area can cover aneurysms, thereby effectively treating intracranial aneurysms and improving treatment outcomes. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention.

[0024] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the present invention.

[0025] Figure 3 This is a schematic diagram of the structure of Embodiment 3 of the present invention.

[0026] Figure 4 This is a schematic diagram of the structure of Embodiment 4 of the present invention.

[0027] Figure 5 This is a schematic diagram of the structure of Embodiment 5 of the present invention.

[0028] Figure 6 This is a schematic diagram of the structure of Embodiment 6 of the present invention.

[0029] Figure 7 This is a schematic diagram of the structure of Embodiment 7 of the present invention.

[0030] Figure 8 This is a structural schematic diagram of Embodiment 8 of the present invention.

[0031] Figure 9 This is a schematic diagram of the structure of Embodiment 9 of the present invention. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0033] like Figure 1As shown, this invention discloses a blood flow guiding embolization stent, including a stent body 1. The stent body 1 is an integral structure woven from at least two types of metal wires of different hardness. The stent body 1 includes a single-layer region 2 and a layered region 3. The layered region 3 is disposed at least at one end of the single-layer region 2. The weaving density of the single-layer region 2 is greater than that of the layered region 3, so as to achieve the occlusion of the aneurysm neck through the single-layer region 2. The layered region 3 has higher flexibility and freedom. The layered region 3 is a mesh structure of at least two layers gradually separated and woven from the single-layer region 2. The hardness of each mesh structure decreases from the outside to the center of the stent body 1. The outermost mesh structure has the highest hardness, forming an anchoring and protective part that contacts the inner wall of the blood vessel and plays an anchoring role, while also providing support. The hardness of the remaining mesh structures in the layered region 3 is less than that of the outermost mesh structure, forming a blood flow channel establishment part, which plays an auxiliary support role and is used to maintain the blood flow path to achieve the drainage effect, while also protecting the blood vessel. Of course, setting up a layered region can improve the flexibility of both ends of the stent body.

[0034] In this invention, the weaving density of the outermost mesh structure is less than that of the remaining mesh structures in the layered region 3, so that the outermost mesh structure can avoid the collateral vessels. The weaving density of the remaining mesh structures is greater than that of the outermost mesh structure, which can improve its own structural stability.

[0035] Preferably, the layered region 3 has two layers, namely an outer layer 31 and an inner layer 32. The hardness of the outer layer 31 is greater than that of the inner layer 32, but the hardness of both is less than that of the single-layer region 2.

[0036] In this invention, the metal wires can achieve different hardnesses through different materials, wire diameters, and / or cross-sectional shapes. Preferably, the metal wires are provided with two hardnesses, where the harder metal wire serves as the main support structure, while the softer metal wire fills the gaps to ensure sufficient coverage, thereby achieving the therapeutic effect.

[0037] The outer layer 31 uses the hardest metal wire as the main support structure, and the hardness of the outer layer 31 is adjusted by changing the weaving density. The inner layer 32 uses the hardest metal wire to fill the gaps, and the hardness of the inner layer 32 is adjusted by changing the weaving density to achieve the appropriate softness.

[0038] In this invention, the metal wire is made of one or more of stainless steel, nickel-titanium alloy, cobalt-chromium alloy, platinum, iridium, and tungsten, preferably cobalt-chromium or nickel-titanium. Cobalt-chromium alloy has high strength and corrosion resistance, and its hardness is also high. Nickel-titanium alloy is a shape memory metal, and its high elasticity and corrosion resistance are very suitable for human blood vessels.

[0039] The cross-sectional shape of the metal wire can be one or more of the following: circular, elliptical, and polygonal. A polygonal shape can be rectangular, square, or triangular. Two different shapes can be used for metal wires of different hardnesses, or they can be achieved using the same shape. Different cross-sectional shapes exhibit different performance effects (hardness, flexibility, and bending ability, etc.). In this invention, the number of metal wires in a single-layer region is the sum of the number of metal wires in the layered regions, and the ratio of the number of metal wires in the outer layer 31 to the inner layer 32 is less than or equal to 1:1.

[0040] In the metal wire, the outer layer 31 has a wire diameter of 0.0005”-0.004” and a circular or square cross-section; the inner layer 32 has a wire diameter of 0.0001”-0.003” and a circular or rectangular cross-section.

[0041] The longitudinal section of the outer layer 31 is tapered or a variable diameter circular tube, and its maximum diameter is greater than the outer diameter of the support body 1, which can increase the anchoring capacity.

[0042] It is cone-shaped. When the stent is released, the outermost ring with the largest diameter will contact the blood vessel first and be released at a fixed point. The remaining part will gradually expand and contact the blood vessel as the stent is released, so that the stent can better adhere to the wall.

[0043] Variable-diameter tubular stents are more suitable for use on aneurysms in blood vessels with significant differences in size. For example, if a blood vessel has a diameter of 4mm on the left and 3mm on the right, and the aneurysm is located in the middle or near the middle of this blood vessel, a variable-diameter stent is used when the implanted stent must cover the blood vessels with different diameters on both sides.

[0044] In this invention, the lengths of the outer layer 31 and the inner layer 32 have three forms: equal, the length of the outer layer 31 is less than the length of the inner layer 32, or the length of the outer layer 31 is greater than the length of the inner layer 32.

[0045] Example 1

[0046] like Figure 1 As shown, in Embodiment 1, the layered regions 3 are symmetrically arranged at both ends of the single-layer region 2, the outer layer 31 is conical, and the lengths of the outer layer 31 and the inner layer 32 are equal.

[0047] Example 2

[0048] like Figure 2 As shown, in embodiment 2, the layered regions 3 are symmetrically arranged at both ends of the single-layer region 2, the outer layer 31 is conical, and the length of the outer layer 31 is greater than the length of the inner layer 32.

[0049] Example 3

[0050] like Figure 3As shown, in embodiment 3, the layered regions 3 are symmetrically arranged at both ends of the single-layer region 2, the outer layer 31 is conical, and the length of the outer layer 31 is less than the length of the inner layer 32.

[0051] Example 4

[0052] like Figure 4 As shown, in embodiment 4, the layered regions 3 are symmetrically arranged at both ends of the single-layer region 2. The outer layer 31 is in the shape of a variable diameter tube. The length of the outer layer 31 is equal to the length of the inner layer 32. The outer layer 31 includes a tapered section and a straight pipe section. The tapered section connects the straight pipe section and the single-layer region 2.

[0053] Example 5

[0054] like Figure 5 As shown, in Embodiment 5, the difference from Embodiment 4 is that the length of the outer layer 31 is greater than the length of the inner layer 32.

[0055] Example 6

[0056] like Figure 6 As shown, in Embodiment 6, the difference from Embodiment 4 is that the length of the outer layer 31 is less than the length of the inner layer 32.

[0057] Example 7

[0058] like Figure 7 As shown, in Embodiment 7, the difference from Embodiment 4 is that the length of the outer layer 31 is the same as the length of the inner layer 32, and the inner diameter of the straight pipe section of the outer layer 31 is slightly larger than the outer diameter of the single-layer region 2.

[0059] Example 8

[0060] like Figure 8 As shown, in Embodiment 8, the difference from Embodiment 7 is that the length of the outer layer 31 is greater than the length of the inner layer 32.

[0061] Example 9

[0062] like Figure 9 As shown, in Embodiment 9, the difference from Embodiment 7 is that the length of the outer layer 31 is less than the length of the inner layer 32.

[0063] In this invention, when the inner layer 32 and the outer layer 31 have equal lengths, the performance in all aspects is more balanced and the structure is stable.

[0064] When the outer layer 31 is longer than the inner layer 32: the outer layer 31, which serves as support, is longer than the inner layer 32, which serves as drainage, ensuring sufficient support length and adequate protection for the inner layer. Furthermore, in practical use, this structure allows the outer layer 31 to preferentially contact blood vessels, enabling pre-deployment of positioning points before releasing the remaining portion.

[0065] When the inner layer 32 is longer than the outer layer 31: Because the inner layer 32 has higher flexibility, it can better adapt to the curvature of the blood vessel and be set longer. Therefore, when applied to aneurysms located before the bend of the blood vessel, it can achieve a smoother and more stable drainage effect. After establishing a stable blood flow channel, the outer layer 31 is then used to fix both sides of the aneurysm.

[0066] The present invention has the following advantages:

[0067] While possessing higher strength and radial support, it also enhances its overall flexibility and elasticity. During use, it can not only make it easier for doctors to operate and provide effective aneurysm embolization to achieve the treatment goal, but also reduce damage to blood vessels.

[0068] The outer layer provides better positioning capabilities, facilitating stability during the doctor's procedure and preventing slippage or displacement during and after stent implantation.

[0069] The layered structure at the end divides the stent into inner and outer layers. When the outer layer covers the inner layer, it can protect the inner layer, while the inner layer provides auxiliary support to establish a blood flow channel. When the inner layer is longer than the outer layer, the soft inner layer is released first to maintain the blood flow channel, and then the outer layer is released to provide positioning support. The main stress-bearing part of the stent body is on the outer layer, which can not only share the pressure on the inner channel, but also reduce the damage to the blood vessel during the release process.

Claims

1. A flow-directing embolization stent, comprising a stent body (1), characterized in that: The stent body (1) is an integral structure woven from at least two kinds of metal wires with different hardnesses. The stent body (1) includes a single-layer area (2) and a layered area (3). The layered area (3) is located at least at one end of the single-layer area (2). The weaving density of the single-layer area (2) is greater than that of the layered area (3). The layered area (3) is a mesh structure of at least two layers gradually separated and woven from the single-layer area (2). The hardness of each layer of the mesh structure decreases from the outside to the center of the stent body (1). The outermost mesh structure is the anchoring support part. The weaving density of the outermost mesh structure is less than that of the remaining mesh structures in the layered area (3). The remaining mesh structures in the layered area (3) are the blood flow channel establishment part, and at the same time play an auxiliary support and protection role.

2. The blood flow diversion embolization stent according to claim 1, characterized in that: The layered area (3) has two layers, namely an outer layer (31) and an inner layer (32). The hardness of the outer layer (31) is greater than that of the inner layer (32), and the weaving density of the outer layer (31) is less than that of the inner layer (32).

3. The blood flow diversion embolization stent according to claim 2, characterized in that: The longitudinal section of the outer layer (31) is tapered or variable diameter circular tube, and its maximum diameter is greater than the outer diameter of the support body (1).

4. The blood flow diversion embolization stent according to claim 3, characterized in that: The metal wire is made of one or more of the following materials: stainless steel, nickel-titanium alloy, cobalt-chromium alloy, platinum, iridium, and tungsten.

5. The blood flow diversion embolization stent according to claim 4, characterized in that: The cross-section of the metal wire is at least one of circular, elliptical, or polygonal.

6. The blood flow diversion embolization stent according to claim 5, characterized in that: The polygon is a rectangle or a triangle.

7. The blood flow diversion embolization stent according to claim 6, characterized in that: The outer layer (31) has a wire diameter of 0.0005”-0.004”, and the inner layer (32) has a wire diameter of 0.0001”-0.003”.

8. The flow diversion embolization stent according to any one of claims 2-7, characterized in that: The outer layer (31) and the inner layer (32) are of equal length, the outer layer (31) is shorter than the inner layer (32) or the outer layer (31) is longer than the inner layer (32).

9. The blood flow diversion embolization stent according to claim 8, characterized in that: The layered area (3) is symmetrically arranged at both ends of the single-layer area (2).

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