Novel blood flow guiding device

Abstract

The invention relates to the field of medical instruments, in particular to a novel blood flow guiding device which comprises a first support and a second support. The second bracket is provided with a head section, a middle section and a tail section; the metal coverage rate of the first bracket is configured to be low metal coverage rate; under the condition that the second support is completely arranged in the first support, an overlapping structure formed by the first support and the head section is defined as a first overlapping structure, an overlapping structure formed by the first support and the middle section is defined as a second overlapping structure, and an overlapping structure formed by the first support and the tail section is defined as a third overlapping structure; the metal coverage rate of the first overlapping structure and the metal coverage rate of the third overlapping structure are respectively larger than the metal coverage rate of the first support and are respectively smaller than the metal coverage rate of the second overlapping structure, and the metal coverage rate of at least the second overlapping structure is configured to be high metal coverage rate. The first support is limited to be low in metal coverage rate, the purpose of improving the trafficability is achieved, and the supporting force of the first support is improved through the second support.

Description

Technical Field

[0001] The present invention relates to the field of medical devices, in particular to a novel blood flow guiding device. Background Art

[0002] A blood flow diversion device is essentially a vascular stent. When used to treat intracranial aneurysms, these devices are typically manufactured in three different metal coverage categories: low metal coverage, high metal coverage, and both low and high metal coverage.

[0003] The prior art provides a patent document entitled "Self-expanding intracranial artery stent" (referred to as "vascular stent") with application number 201020659175.0. The vascular stent described in this patent document is essentially a blood flow guiding device with a low metal coverage ratio.

[0004] The vascular stent is limited to a low metal coverage, resulting in low rigidity of the vascular stent and high flexibility, so that the vascular stent has relatively high passability in the tortuous position of the intracranial artery (for example, the intracranial artery siphon segment). However, the low rigidity of the vascular stent results in low supporting force of the vascular stent in the intracranial artery.

[0005] The prior art also provides a patent document entitled "Intracranial Stent and Intracranial Stent Delivery System" (hereinafter referred to as "Intracranial Stent") with application number 202111302295.4. The intracranial stent described in this patent document is essentially a blood flow guiding device with a high metal coverage rate.

[0006] The intracranial stent is limited to a high metal coverage, resulting in high rigidity of the intracranial stent and low flexibility. The high rigidity of the intracranial stent leads to high supporting force of the intracranial stent in the intracranial artery. However, the passability of the intracranial stent in tortuous locations of the intracranial artery (for example, the siphon segment of the intracranial artery) is relatively low.

[0007] In the prior art, there is another patent document entitled "A blood flow guiding device for treating intracranial aneurysms" (hereinafter referred to as "guiding device"), with application number 202021228902.8. The guiding device described in this patent document is essentially a blood flow guiding device with both low metal coverage and high metal coverage.

[0008] The guide device is limited to having both low and high metal coverage, resulting in a guide device having both low and high rigidity structures. The high rigidity structure provides a high support force for the guide device in the intracranial artery, while the low rigidity structure improves the flexibility of the guide device. However, the high rigidity of the structure affects the guide device's ability to pass through tortuous locations in the intracranial artery (e.g., the siphon segment of the intracranial artery), resulting in relatively low passability.

[0009] In addition, when the above-mentioned guide device is specifically arranged at a tortuous position of an intracranial artery, the guide device may experience stress concentration.

[0010] Therefore, how to make the blood flow guiding device have relatively high passability in the tortuous position of the intracranial artery and relatively high supporting force in the intracranial artery while reducing stress concentration becomes a technical problem to be solved. Summary of the Invention

[0011] In order to solve the technical problem of how to make the blood flow guiding device have relatively high passability in the tortuous position of the intracranial artery, and how to make the blood flow guiding device have relatively high supporting force in the intracranial artery, while also being able to reduce stress concentration phenomenon, the present invention provides a new blood flow guiding device.

[0012] To achieve the above object, the technical solution adopted by the present invention is:

[0013] According to one aspect of the present invention, there is provided a novel blood flow guiding device comprising a first stent and a second stent;

[0014] The first stent and the second stent are both tubular stents made of alloy wires, woven into a diamond-shaped grid structure, and having a self-expanding function. The length of the first stent is greater than the length of the second stent. The alloy wires of the first stent are defined as first alloy wires, and the alloy wires of the second stent are defined as second alloy wires.

[0015] The second bracket is provided with a head section, a middle section and a tail section, wherein the middle section is located between the head section and the tail section, wherein the number of the second alloy wires in the head section and the number of the second alloy wires in the tail section are respectively smaller than the number of the second alloy wires in the middle section;

[0016] The metal coverage of the first bracket is configured as low metal coverage;

[0017] Under the condition that the second bracket is completely disposed in the first bracket, the overlapping structure formed by the first bracket and the head section is defined as a first overlapping structure, the overlapping structure formed by the first bracket and the middle section is defined as a second overlapping structure, and the overlapping structure formed by the first bracket and the tail section is defined as a third overlapping structure;

[0018] The metal coverage of the first overlapping structure and the metal coverage of the third overlapping structure are respectively greater than the metal coverage of the first bracket and respectively less than the metal coverage of the second overlapping structure. At least the metal coverage of the second overlapping structure is configured as high metal coverage.

[0019] Furthermore, the metal coverage of the first stent is limited to a low metal coverage formed by sparsely weaving the first alloy wires.

[0020] Furthermore, the metal coverage of the middle section of the second stent is limited to a low metal coverage formed by sparsely weaving the second alloy wires;

[0021] The diameter of the first alloy wire is the same as the diameter of the second alloy wire, and there is an angle difference between the braiding angle of the first alloy wire and the braiding angle of the second alloy wire;

[0022] The metal coverage of the second overlapping structure is limited to a high metal coverage formed by the overlapping structure of the first bracket and the middle section having the angle difference.

[0023] Furthermore, the number of the first alloy wires and the number of the second alloy wires are 24 respectively;

[0024] The braiding angle of the first alloy wire is specifically 65 degrees, and the braiding angle of the second alloy wire is specifically 75 degrees.

[0025] Furthermore, the metal coverage of the middle section of the second stent is limited to a high metal coverage formed by densely weaving the second alloy wires;

[0026] The diameter of the first alloy wire is the same as the diameter of the second alloy wire;

[0027] The metal coverage of the second overlapping portion is limited to a high metal coverage formed by the overlapping structure of the first bracket with low metal coverage and the middle section with high metal coverage.

[0028] Furthermore, the number of the first alloy wires is 24, and the number of the second alloy wires is 48.

[0029] Furthermore, the number of the first alloy wires is the same as the number of the second alloy wires, the diameter of the second alloy wire is greater than the diameter of the first alloy wire, and the number of intersections per unit area of ​​the second alloy wires is the same as the number of intersections per unit area of ​​the first alloy wires, so that the metal coverage of the second bracket is different from the metal coverage of the first bracket, wherein the metal coverage of the second bracket is greater than the metal coverage of the first bracket;

[0030] The metal coverage of the second overlapping portion is limited to a high metal coverage formed by the overlapping structure of the first bracket and the middle section having different metal coverages.

[0031] Furthermore, the high metal coverage is specifically one of the metal coverages between 30% and 35%.

[0032] Furthermore, both ends of the first bracket are made using an open weaving process.

[0033] Furthermore, the first alloy wire and the second alloy wire are respectively made of nickel-titanium alloy.

[0034] The above technical solution has the following advantages or beneficial effects:

[0035] The present invention provides a novel blood flow guiding device, in which the first stent is limited to a low metal coverage rate, thereby achieving the purpose of improving the passability; the supporting force of the first stent is increased by the second stent; the first overlapping structure and the third overlapping structure are formed with the first stent by the head section and the tail section of the second stent respectively, so that the stress of the first stent can form a gradient distribution in the length direction of the first stent through the first overlapping structure and the third overlapping structure; the first stent and the second stent are woven into a diamond grid structure, and under the condition of low metal coverage, the number of intersections of alloy wires per unit area of ​​the two is reduced, so that the stress of the intersections is dispersed to a relatively large area. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic structural diagram of a novel blood flow guiding device provided by an embodiment of the present invention;

[0037] Figure 2 A schematic structural diagram of a first bracket provided in an embodiment of the present invention;

[0038] Figure 3 A schematic structural diagram of a second bracket provided in an embodiment of the present invention;

[0039] Figure 4 A schematic diagram of the braiding angle provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] Example 1:

[0041] In this embodiment, a new blood flow guiding device is provided to solve the technical problem of how to make the blood flow guiding device have relatively high passability in the tortuous position of the intracranial artery, and the blood flow guiding device has relatively high supporting force in the intracranial artery, and at the same time, it can also reduce the stress concentration phenomenon.

[0042] For details, see Figures 1 to 3 , a novel blood flow guiding device of this embodiment includes a first stent 1 and a second stent 2;

[0043] The first stent 1 and the second stent 2 are tubular stents made of alloy wires, woven into a diamond-shaped grid structure, and having a self-expanding function. The length of the first stent 1 is greater than that of the second stent 2. The alloy wires of the first stent 1 are defined as first alloy wires, and the alloy wires of the second stent 2 are defined as second alloy wires.

[0044] The second bracket 2 is provided with a head section 201, a middle section 202 and a tail section 203. The middle section 202 is located between the head section 201 and the tail section 203. The number of second alloy wires in the head section 201 and the number of second alloy wires in the tail section 203 are respectively smaller than the number of second alloy wires in the middle section 202.

[0045] The metal coverage of the first bracket 1 is configured as low metal coverage;

[0046] Under the condition that the second bracket 2 is completely disposed in the first bracket 1, the overlapping structure formed by the first bracket 1 and the head section 201 is defined as the first overlapping structure C1, the overlapping structure formed by the first bracket 1 and the middle section 202 is defined as the second overlapping structure C2, and the overlapping structure formed by the first bracket 1 and the tail section 203 is defined as the third overlapping structure C3;

[0047] The metal coverage of the first overlapping structure C1 and the metal coverage of the third overlapping structure C3 are respectively greater than the metal coverage of the first bracket 1 and less than the metal coverage of the second overlapping structure C2. At least the metal coverage of the second overlapping structure C2 is configured as high metal coverage.

[0048] In this embodiment, the metal coverage of the first bracket 1 is configured to be low metal coverage, so that the first bracket 1 has relatively high flexibility; at the same time, since the metal coverage of the first bracket 1 is low metal coverage, the rigidity of the first bracket 1 is relatively low. In other words, the elastic force of the first bracket 1 itself is relatively low.

[0049] In this embodiment, the metal coverage of the second bracket 2 is configured to be low metal coverage, so that the second bracket 2 has relatively high flexibility; at the same time, since the metal coverage of the second bracket 2 is low metal coverage, the rigidity of the second bracket 2 is relatively low. In other words, the elastic force of the second bracket 2 itself is relatively low.

[0050] Since the first stent 1 and the second stent 2 are respectively limited to a low metal coverage, when the second stent 2 is arranged in the first stent 1, the outer diameter of the overlapping structure (including the first to third overlapping structures C3) can be effectively reduced, thereby avoiding the new blood flow guiding device of this embodiment from applying a greater elastic force to the inner wall of the intracranial artery when it is arranged in the intracranial artery.

[0051] In this embodiment, the material of the first bracket 1 and the material of the second bracket 2 are respectively alloy wires; wherein the alloy wire of the first bracket 1 is defined as a first alloy wire, and the alloy wire of the second bracket 2 is defined as a second alloy wire. The first alloy wire and the second alloy wire can be configured to be the same material or different materials;

[0052] In this embodiment, preferably, the first alloy wire and the second alloy wire are configured to be the same material; specifically, the first alloy wire and the second alloy wire are preferably made of nickel-titanium alloy material.

[0053] It should be understood that nickel-titanium alloy material is one of the commonly used materials for manufacturing vascular stents (blood flow guiding devices). This is common knowledge known to those skilled in the art and will not be elaborated here.

[0054] It should be understood that in other embodiments, the first alloy wire and the second alloy wire may also be configured as different materials, for example: the first alloy wire may be configured as nickel-titanium alloy material, and the second alloy wire may be configured as cobalt-chromium alloy or platinum-tungsten alloy. However, the rigidity of these two materials is respectively higher than that of nickel-titanium alloy. The flexibility of the second stent 2 manufactured from cobalt-chromium alloy or platinum-tungsten alloy is significantly reduced, and thus the passability of the second stent 2 through the tortuous position of the intracranial artery is lower than the passability of the second stent 2 manufactured from nickel-titanium alloy through the tortuous position of the intracranial artery.

[0055] In this embodiment, the metal coverage of the first bracket 1 is limited to a low metal coverage formed by sparsely weaving the first alloy wires.

[0056] The opposite of the sparse weaving method is the dense weaving method. The specific weaving processes of the sparse weaving method and the dense weaving method are common knowledge known to those skilled in the art and will not be described in detail here.

[0057] In this embodiment, after the plurality of first alloy wires of the first stent 1 are woven in a sparse weaving manner, the mesh size of the first stent 1 is relatively large; corresponding to the first reference stent woven in a dense weaving manner, the mesh size of the first reference stent is relatively small;

[0058] In this embodiment, the mesh size of the first bracket 1 is relatively large, resulting in a relatively low rigidity of the first bracket 1. In other words, the elastic force of the first bracket 1 is relatively low; corresponding to the first reference bracket woven in a dense weaving manner, the mesh size of the first reference bracket is relatively small, resulting in a relatively high rigidity of the first reference bracket. In other words, the elastic force of the first reference bracket is relatively high.

[0059] In the novel blood flow guiding device of this embodiment, the metal coverage of the middle section 202 of the second stent 2 is limited to a low metal coverage formed by sparsely weaving the second alloy wire;

[0060] The diameter of the first alloy wire is the same as the diameter of the second alloy wire, and the braiding angle of the first alloy wire and the braiding angle of the second alloy wire have an angle difference;

[0061] The metal coverage of the second overlapping structure C2 is limited to a high metal coverage formed by the overlapping structure of the first bracket 1 and the middle section 202 having an angle difference.

[0062] In this embodiment, the weaving method of the second bracket 2 is the same as the weaving method of the aforementioned first bracket 1, both of which adopt a sparse weaving method. At the same time, the diameter of the second alloy wire of the second bracket 2 is the same as the diameter of the first alloy wire of the first bracket 1. Therefore, the metal coverage of the second bracket 2 is also a low metal coverage, which is the same as or close to the low metal coverage of the first bracket 1.

[0063] In this embodiment, since the multiple second alloy wires of the second bracket 2 are sparsely woven, the mesh size of the second bracket 2 is relatively large, resulting in relatively low rigidity of the second bracket 2. In other words, the elastic force of the second bracket 2 is relatively low.

[0064] As previously mentioned, when the second bracket 2 is disposed within the first bracket 1, at least the metal coverage of the second overlapping structure C2 is high. The high metal coverage of the second overlapping structure C2 is formed by overlapping the first bracket 1 with a low metal coverage and the second bracket 2 with a low metal coverage, and by having the braiding angle of the first alloy wire of the first bracket 1 and the braiding angle of the second alloy wire of the second bracket 2 be different.

[0065] Specifically, the braiding angle of the first alloy wire of the first bracket 1 is defined as a first angle, and the braiding angle of the second alloy wire of the second bracket 2 is defined as a second angle. The first angle and the second angle have an angle difference; see Figure 1 When the second bracket 2 is arranged in the first bracket 1, along the radial direction of the first bracket 1, a part of the first alloy wire of the first bracket 1 covers the mesh of a part of the diamond grid structure of the second bracket 2. Similarly, a part of the second alloy wire of the second bracket 2 covers the mesh of a part of the diamond grid structure of the first bracket 1. Overall, the first alloy wire of the first bracket 1 and the second alloy wire of the second bracket 2 form a mutually staggered positional relationship, resulting in that when a person observes the second overlapping structure C2 along the radial direction of the first bracket 1, the mesh of the diamond grid structure of the first bracket 1 is covered by the second alloy wire, resulting in a phenomenon of reduced mesh size. Correspondingly, the mesh of the diamond grid structure of the second bracket 2 is covered by the first alloy wire, resulting in a phenomenon of reduced mesh size. Therefore, the metal coverage rate of the second overlapping structure C2 changes from the original low metal coverage rate of the first bracket 1 and the low metal coverage rate of the second bracket 2 to a high metal coverage rate.

[0066] In this embodiment, see Figure 1 , the metal coverage of the first overlapping structure C1 and the metal coverage of the third overlapping structure C3 are respectively less than the metal coverage of the second overlapping structure C2, and respectively greater than the metal coverage of the first bracket 1;

[0067] For details, see Figures 1 to 3 The first overlapping structure C1 is formed by overlapping a portion of the first bracket 1 and the head section 201 of the second bracket 2. In the first overlapping structure C1, the braiding angle of the first alloy wires of the first bracket 1 is different from the braiding angle of the second alloy wires of the head section 201 of the second bracket 2, so that a portion of the first alloy wires covers the meshes of the diamond mesh structure of the head section 201 of the second bracket 2, and a portion of the second alloy wires of the head section 201 of the second bracket 2 covers the meshes of the diamond mesh structure of the first bracket 1. As a result, the metal coverage of the first overlapping structure C1 is higher than the metal coverage of the first bracket 1.

[0068] Also, see Figures 1 to 3 Since the number of second alloy wires in the head section 201 of the second bracket 2 is smaller than that in the middle section 202 of the second bracket 2, the mesh size of the diamond-shaped grid structure in the head section 201 of the second bracket 2 is larger than the mesh size of the diamond-shaped grid structure in the middle section 202 of the second bracket 2. This causes the mesh size of the diamond-shaped grid of the first bracket 1 to exhibit two phenomena:

[0069] The first phenomenon is that "in the first overlapping structure C1, the number of meshes of the diamond-shaped mesh structure of the first stent 1 covered by the second alloy wires of the head section 201 of the second stent 2" is smaller than "in the second overlapping structure C2, the number of meshes of the diamond-shaped mesh structure of the first stent 1 covered by the second alloy wires of the middle section 202 of the second stent 2";

[0070] For example, in the first overlapping structure C1, with the axis of the first stent 1 as the axis, along the circumferential direction, the number of meshes in the diamond-shaped grid structure of the first stent 1 is 10 (this is a hypothetical number and is not intended to limit the novel blood flow guiding device of this embodiment). Then, the second alloy wire of the head segment 201 of the second stent 2 covers 5 of the 10 meshes (this is a hypothetical number and is not intended to limit the novel blood flow guiding device of this embodiment).

[0071] Correspondingly, in the second overlapping structure C2, along the circumferential direction, the number of meshes of the diamond-shaped grid structure of the first stent 1 is 10 (this is an assumed number and is not intended to limit the novel blood flow guiding device of this embodiment). Then, the second alloy wire of the middle section 202 of the second stent 2 covers all 10 meshes (this is an assumed number and is not intended to limit the novel blood flow guiding device of this embodiment).

[0072] Since the amount of mesh of the first bracket 1 covered by the second alloy wire of the head section 201 of the second bracket 2 is less than the amount of mesh of the first bracket 1 covered by the second alloy wire of the middle section 202 of the second bracket 2, the metal coverage of the first overlapping structure C1 is less than the metal coverage of the second overlapping structure C2.

[0073] The second phenomenon is that "in the first overlapping structure C1, the number of meshes of the diamond-shaped mesh structure of the first bracket 1 covered by the second alloy wires of the head section 201 of the second bracket 2" is equal to "in the second overlapping structure C2, the number of meshes of the diamond-shaped mesh structure of the first bracket 1 covered by the second alloy wires of the middle section 202 of the second bracket 2", but "in the first overlapping structure C1, the number of second alloy wires of the head section 201 of the second bracket 2 used to cover the meshes of the first bracket 1" is less than "in the second overlapping structure C2, the number of second alloy wires of the middle section 202 of the second bracket 2 used to cover the meshes of the first bracket 1";

[0074] For example, in the first overlapping structure C1, the number of meshes in the diamond-shaped grid structure of the first stent 1 along the circumferential direction is 10 (this is a hypothetical number and is not intended to limit the novel blood flow guiding device of this embodiment). Then, the second alloy wire of the head section 201 of the second stent 2 covers all 10 meshes (this is a hypothetical number and is not intended to limit the novel blood flow guiding device of this embodiment). However, each mesh of the first stent 1 is covered by one second alloy wire (this is a hypothetical number and is not intended to limit the novel blood flow guiding device of this embodiment).

[0075] Correspondingly, in the second overlapping structure C2, along the circumferential direction, the number of meshes of the diamond-shaped grid structure of the first stent 1 is 10 (this is a hypothetical number and is not intended to limit the novel blood flow guiding device of this embodiment). Thus, the second alloy wires of the middle section 202 of the second stent 2 cover all 10 meshes (this is a hypothetical number and is not intended to limit the novel blood flow guiding device of this embodiment). However, each mesh of the first stent 1 is covered by two or three second alloy wires (this is a hypothetical number and is not intended to limit the novel blood flow guiding device of this embodiment).

[0076] Since "the number of second alloy wires used to cover the mesh of the first bracket 1 in the first overlapping structure C1" is less than "the number of second alloy wires used to cover the mesh of the first bracket 1 in the second overlapping structure C2", the metal coverage of the first overlapping structure C1 is less than the metal coverage of the second overlapping structure C2.

[0077] Similarly, the structure of the third overlapping structure C3 is the same as that of the first overlapping structure C1, and the metal coverage of the third overlapping structure C3 is the same as or similar to the metal coverage of the first overlapping structure C1. For the principle of the metal coverage of the third overlapping structure C3, please refer to the above-mentioned principle description of the first overlapping structure C1, which will not be repeated here.

[0078] In this embodiment, the number of the first alloy wires and the number of the second alloy wires are 24 respectively;

[0079] The braiding angle of the first alloy wire is specifically 65 degrees, and the braiding angle of the second alloy wire is specifically 75 degrees.

[0080] In a novel blood flow guiding device of this embodiment, the first stent 1 is made of 24 first alloy wires and is made through a weaving process, and the second stent 2 is made of 24 first alloy wires and is made through a weaving process, so that the metal coverage rate of the first stent 1 and the metal coverage rate of the second stent 2 respectively form a low metal coverage rate; when the second stent 2 is arranged in the first stent 1, at least the sum of the number of the first alloy wires and the second alloy wires of the second covering structure is 48.

[0081] The structure of the first bracket 1 is different from that of the second bracket 2;

[0082] Specifically, the first bracket 1 is divided into several sections along the length direction, and the number of first alloy wires of any two adjacent sections of the first bracket 1 is the same; and the number of first alloy wires of the first bracket 1 is limited to 24.

[0083] See also Figures 1 to 3 , along the length direction of the second bracket 2, the second bracket 2 is divided into the aforementioned head section 201, the middle section 202, and the tail section 203, wherein the number of second alloy wires in the head section 201 is less than the number of second alloy wires in the middle section 202, and the number of second alloy wires in the tail section 203 is less than the number of second alloy wires in the middle section 202;

[0084] Furthermore, along the direction from the head section 201 to the middle section 202, the number of the second alloy wires is configured to be arranged in a manner of gradually increasing the number of wires. For example, if the number of the second alloy wires in the head section 201 is 5 (this is an assumed number and is not used to limit the novel blood flow guiding device of this embodiment), and if the number of the second alloy wires in the middle section 202 is 10 (this is an assumed number and is not used to limit the novel blood flow guiding device of this embodiment), then, along the direction from the head section 201 to the middle section 202, one or two second alloy wires are added (this is an assumed number and is not used to limit the novel blood flow guiding device of this embodiment). In a novel blood flow guiding device according to an embodiment, the number of second alloy wires in the head section 201 is configured as 5 alloy wires at the end, 6 or 7 alloy wires between the intersection of the end and the middle section 202 (the head section 201 has a basic number of 5 second alloy wires, plus 1 or 2 second alloy wires), and 11 or 12 alloy wires between the intersection of the end and the middle section 202 and the middle of the middle section 202 (the middle section 202 has a basic number of 10 second alloy wires, plus 1 or 2 second alloy wires). The number of second alloy wires in the entire middle section 202 is described below and is not mentioned here for the time being.

[0085] Correspondingly, along the direction from the tail section 203 to the middle section 202, the number of second alloy wires is configured to be the same as the number of second alloy wires "along the direction from the head section 201 to the middle section 202" mentioned above. In other words, the two are the same or similar configurations and will not be repeated here.

[0086] It is worth noting that, since the number of second alloy wires is increased along the direction from the head section 201 to the middle section 202 and along the direction from the tail section 203 to the middle section 202, respectively, the number of second alloy wires is also increased for the middle section 202, and the number of second alloy wires in the middle section 202 is the sum of the number of the aforementioned basic second alloy wires, the number of the second alloy wires added to the head section 201, and the number of the second alloy wires added to the tail section 203; and, in the second bracket 2 in this embodiment, the number of second alloy wires in section 202 is limited to 24.

[0087] As mentioned above, the braiding angle of the first alloy wire and the braiding angle of the second alloy wire have an angle difference, the purpose of which is to make the first bracket 1 and the second bracket 2 form a high metal coverage together;

[0088] In this embodiment, the braiding angle of the first alloy wire is 65 degrees, and the braiding angle of the second alloy wire is 75 degrees, so that the braiding angle of the first alloy wire and the braiding angle of the second alloy wire form an angle difference;

[0089] In the known prior art, there are two ways to express the braiding angle, namely;

[0090] The first way to express the braiding angle is to use the axis of the blood flow guide device as a reference, and the angle (which can be acute or obtuse) formed by a single wire relative to the axis is used as the braiding angle;

[0091] The second way to express the braiding angle (see Figure 4 ): Taking the diameter direction of the blood flow guiding device as a reference, the angle formed by a single wire relative to the diameter direction (which can be an acute angle or an obtuse angle) is used as the braiding angle.

[0092] The braiding angle mentioned in the technical solution of this embodiment should be understood according to the expression of the second braiding angle.

[0093] The braiding angle has a significant impact on the parameters of the single-layer braided blood flow guide device, such as the radial support force and radial rebound rate of the blood flow guide device, but this is not emphasized in the technical solution of this embodiment; in the technical solution of this embodiment, more emphasis is placed on the fact that the braiding angle of the first alloy wire and the braiding angle of the second alloy wire are different, so that the metal coverage can be changed after the first stent 1 and the second stent 2 overlap.

[0094] The braiding angle of the first alloy wire of the first stent 1 is relatively small, which is intended to improve the flexibility of the first stent 1 and increase the porosity of the first stent 1. This setting can reduce the area of ​​the branch blood vessels (bifurcation blood vessels) covered by the first stent 1;

[0095] The braiding angle of the second alloy wire of the second stent 2 is relatively large, the purpose of which is to increase the supporting force of the second stent 2 and reduce the porosity of the second stent 2, so that when the second stent 2 covers the intersection of the aneurysm and the intracranial artery, the second stent 2 can enhance the blood flow retention effect.

[0096] When the second bracket 2 is disposed within the first bracket 1, the positional relationship between the first alloy wires and the second alloy wires of the first overlapping structure C1 is such that, due to the different angles between the first alloy wires and the second alloy wires of the first overlapping structure C1, the first alloy wires can cover the meshes of the diamond-shaped mesh structure of the second bracket 2, and the second alloy wires can cover the meshes of the diamond-shaped mesh structure of the first bracket 1. In other words, the first alloy wires and the second alloy wires do not overlap with each other.

[0097] When the second bracket 2 is arranged in the first bracket 1, the positional relationship between the first alloy wire and the second alloy wire of the second overlapping structure C2, and the positional relationship between the first alloy wire and the second alloy wire of the third overlapping structure C3 are respectively the same as or similar to the positional relationship between the first alloy wire and the second alloy wire of the aforementioned first overlapping structure C1, and are not repeated here.

[0098] Furthermore, in the novel blood flow guiding device of this embodiment, the high metal coverage is specifically one of the metal coverages between 30% and 35%.

[0099] Generally speaking, in the art, a metal coverage equal to or greater than 30% is considered high metal coverage;

[0100] On the one hand, both the prior art blood flow guiding device and the novel blood flow guiding device of this embodiment essentially reduce blood flow into the aneurysm. Therefore, a high metal coverage ratio indicates a high density of the blood flow guiding device between the blood flow and the aneurysm, while a low metal coverage ratio (a metal coverage ratio below 30%) indicates a low density of the blood flow guiding device between the blood flow and the aneurysm. Those skilled in the art will readily understand that a high-density blood flow guiding device blocks more blood flow, while a low-density blood flow guiding device blocks less blood flow.

[0101] On the other hand, both the blood flow guiding device of the prior art and the novel blood flow guiding device of the present embodiment essentially change the blood flow direction of the aneurysm artery to reduce or weaken the blood flow impact within the aneurysm, thereby achieving the purpose of blood retention and thrombosis within the aneurysm; ultimately, new endothelial cells are formed on the surface of the blood flow guiding device and at the aneurysm neck, thereby achieving complete closure and healing of the aneurysm.

[0102] Based on the above two reasons, for the novel blood flow guiding device of this embodiment, the higher the metal coverage, the better. Instead, the metal coverage should be limited to a reasonable range, especially the high metal coverage should be limited to a reasonable range. In this embodiment, a metal coverage of 35% is one of the high metal coverages and is the highest metal coverage that the inventors of this application believe can keep the high metal coverage of the novel blood flow guiding device of this embodiment within a reasonable range.

[0103] Since the high metal coverage is limited to a metal coverage of 30% to 35%, the metal coverage of the first stent 1 itself and the metal coverage of the second stent 2 itself are respectively limited; the metal coverage of the first stent 1 itself is not a high metal coverage, and the metal coverage of the first stent 1 itself is not the lower the better, but should be limited to a reasonable range; similarly, the metal coverage of the second stent 2 itself should be limited to a reasonable range, so that it can match the angle difference formed by the braiding angle of the first alloy wire and the braiding angle of the second alloy wire, and finally form a high metal coverage (one of the metal coverages of 30% to 35%) of a new blood flow guidance device of this embodiment.

[0104] It should be understood that the metal coverage of the first bracket 1 and the metal coverage of the second bracket 2 can be specifically achieved through a limited number of manufacturing cycles, as long as the metal coverage of the overlapping structure of the second bracket 2 (at least the second overlapping structure C2) when the second bracket 2 is disposed inside the first bracket 1 reaches one of the aforementioned metal coverages of 30% to 35%;

[0105] It should be understood that, for those skilled in the art, the method for measuring the metal coverage of a blood flow guiding device is common knowledge known to those skilled in the art and will not be described in detail here.

[0106] For further information, see Figures 1 to 3 In this embodiment, a new blood flow guiding device is provided, and both ends of the first stent 1 are made by an open braiding process.

[0107] Among them, the open weaving process is common knowledge known to those skilled in the art. The specific structures at both ends of the first stent 1 manufactured using the open weaving process are common knowledge known to those skilled in the art; for example: in the prior art with the invention name of Zero Exchange Balloon Catheter Stent System with Distal Protection Umbrella and Use Method, application number 202411422340.3, the proximal end of the proximal stent is a braided open-loop structure, which is essentially a structure made by an open weaving process.

[0108] It should be understood that the counterpart of the open braiding process is the closed braiding process. In this embodiment, the open braiding process is adopted so that the two ends of the first stent 1 are in a dispersed state under their own elastic force in a natural state. In contrast, in some prior arts, the guide devices manufactured using the closed braiding process have ring-shaped structures at both ends, which are not the dispersed state of the two ends of the first stent 1 in this embodiment.

[0109] In this embodiment, the two ends of the first stent 1 are made using an open weaving process, the purpose of which is to further improve the passability of the first stent 1; specifically, the rigidity of the two ends of the first stent 1 made by the open weaving process is lower than the rigidity of the structure between the two ends of the first stent 1; from another perspective, when the rigidity of the first stent 1 at the two ends is lower than the rigidity of the first stent 1 located between the two ends, the flexibility of the first stent 1 at the two ends is higher than the flexibility of the first stent 1 located between the two ends, which makes it easier for the first stent 1 at the two ends to deform when subjected to external force (such as resistance from the inner wall of the artery), thereby improving the passability of the first stent 1.

[0110] It should be noted that the novel blood flow guiding device of this embodiment is not simply a structure in which two stents are arranged in a sheath.

[0111] First, from the perspective of passability, the essence is the difficulty of the first stent 1 and the second stent 2 successively passing through or reaching the tortuous position of the intracranial artery;

[0112] In this embodiment, the first stent 1 and the second stent 2 are respectively pushed to the tortuous position of the intracranial artery, or through the tortuous position of the intracranial artery using the pushing mechanism of the prior art, wherein the pushing mechanism includes at least a catheter for limiting the moving path of the first stent 1 and the second stent 2, and a storage structure for accommodating the first stent 1 or the second stent 2, a pushing structure for releasing the first stent 1 or the second stent 2 outside the storage structure and outside the catheter, a guide wire for limiting the first stent 1 or the second stent 2 relative to the catheter, and other structures. These are common knowledge known to those skilled in the art, and their principles will not be repeated here.

[0113] Before the first stent 1 of this embodiment is pushed by the pushing mechanism, one end of the catheter of the pushing mechanism is first inserted into the intracranial artery and reaches or passes through the tortuous position of the intracranial artery. The other end of the catheter is located outside the human body for operation by medical personnel.

[0114] Then, the first stent 1 is placed in the catheter and pushed so that the first stent 1 reaches the intracranial artery along the catheter, wherein the movement path of the first stent 1 is limited within the catheter;

[0115] When the first stent 1 approaches the tortuous position of the intracranial artery, the catheter itself is affected by the tortuous position of the intracranial artery, and the catheter located at the tortuous position of the intracranial artery bends. This causes the first stent 1 to encounter resistance from the inner wall of the catheter when passing through the tortuous position of the catheter. This resistance causes the first stent 1 to undergo elastic deformation and bend. The shape of the first stent 1 after bending is similar to the current curved shape of the catheter, thereby continuing to push the first stent 1 so that the first stent 1 can smoothly pass through the curved position of the catheter.

[0116] In the first prior art (entitled "A Self-Expanding Intracranial Artery Stent [abbreviated as Stent], application number 201020659175.0), the metal coverage of the stent is low, resulting in a relatively low rigidity and high flexibility. The highly flexible stent is more easily traversable through the tortuous locations of the intracranial artery.

[0117] The first stent 1 in this embodiment is configured with a low metal coverage compared to the first prior art, so it has the same or similar flexibility. Therefore, the passability of the first stent 1 in this embodiment is the same or similar to the passability of the vascular stent in the first prior art.

[0118] In the second prior art (entitled "An Intracranial Stent and Intracranial Stent Delivery System [Intracranial Stent], application number 202111302295.4), the metal coverage of the intracranial stent is high, resulting in relatively high rigidity and relatively low flexibility. Vascular stents with relatively low flexibility are not easy to pass through the tortuous position of the intracranial artery, resulting in low passability of the intracranial stent;

[0119] The first stent 1 in this embodiment has a different metal coverage rate compared with the second prior art. The metal coverage rate of the first stent 1 in this embodiment is lower. Therefore, the rigidity of the first stent 1 in this embodiment is lower than the rigidity of the intracranial stent in the second prior art, which makes the flexibility of the first stent 1 in this embodiment higher than the flexibility of the intracranial stent in the second prior art. Therefore, the first stent 1 in this embodiment has higher passability.

[0120] In the third prior art (a blood flow guide device for treating intracranial aneurysms [hereinafter referred to as the guide device], application number 202021228902.8), the stent in the guide device is configured with a distal sparse mesh portion, a central dense mesh portion, and a proximal sparse mesh portion. Although the metal coverage of the distal sparse mesh portion and the proximal sparse mesh portion is low, since the distal sparse mesh portion and the proximal sparse mesh portion are directly connected to the central dense mesh portion, and the metal coverage of the central dense mesh portion is high, the central dense mesh portion has high rigidity but relatively low flexibility. The central dense mesh portion with relatively low flexibility is not easy to pass through the tortuous position of the intracranial artery, resulting in low passability of the guide device;

[0121] Compared with the third prior art, the metal coverage of the first bracket 1 in this embodiment is completely limited to a low metal coverage. Therefore, the rigidity of the first bracket 1 in this embodiment is lower than the rigidity of the central dense mesh part of the guide device of the third prior art, which makes the flexibility of the first bracket 1 in this embodiment higher than the flexibility of the central dense mesh part of the third prior art. Therefore, the passability of the first bracket 1 in this embodiment is higher.

[0122] Therefore, from the perspective of passability, the passability of the first stent 1 in this embodiment is the same as or similar to the passability of the stent (or device) in the prior art that is limited to low metal coverage, and is higher than the passability of the stent (or device) in the prior art that is completely limited to high metal coverage, or higher than the passability of the stent (or device) in the prior art with partial high metal coverage; the high passability of the first stent 1 in this embodiment can make it easier for the first stent 1 to pass through the tortuous position of the intracranial artery and reach a deeper position of the intracranial artery.

[0123] The second bracket 2 in this embodiment is also limited to a low metal coverage, so that the rigidity, flexibility and passability of the second bracket 2 are equal to or similar to those of the first bracket 1, which will not be repeated here.

[0124] Second, from the perspective of supporting force, the essence of supporting force is the resistance of the stent to the vascular pressure in the blood vessel. When a stent is set in a blood vessel, no matter whether the stent is self-expanding or expanded by a balloon, after the stent is expanded, it will inevitably be subjected to the pressure of the blood vessel wall. The pressure of the blood vessel wall can force the already expanded stent to produce a contraction movement trend. If the supporting force of a stent is low, then after the stent is expanded in the blood vessel and subjected to the pressure of the blood vessel wall, the diameter of the stent after expansion will be lower than the ideal diameter. On the contrary, if the supporting force of a stent is relatively high, then after the stent is expanded in the blood vessel and subjected to the pressure of the blood vessel wall, the diameter of the stent after expansion will be close to or reach the ideal diameter.

[0125] The first stent 1 in this embodiment is manufactured using a sparse weaving process, and the metal coverage of the first stent 1 is limited to a low metal coverage, which results in low rigidity of the first stent 1 itself, resulting in low supporting force of the first stent 1 when the first stent 1 is placed in a blood vessel;

[0126] Therefore, in order to improve the support force of the first stent 1, or to improve the support force of the novel blood flow guiding device of this embodiment, this embodiment achieves this by disposing the second stent 2 within the first stent 1 to form an overlapping structure. Specifically, after the first stent 1 has been disposed within the blood vessel, the second stent 2 is disposed within the first stent 1, so that the second stent 2 is deployed by self-expansion. After deployment, the second stent 2 contacts the first stent 1. From the perspective of the force applied to the first stent 1, on the one hand, the outer wall of the first stent 1 is subjected to pressure from the blood vessel wall, causing the first stent 1 to have a contraction tendency. On the other hand, the inner wall of the first stent 1 is subjected to the expansion force of the second stent 2, causing the first stent 1 to have an expansion tendency. Furthermore, the self-expansion force of the first stent 1 itself and the self-expansion force of the second stent 2 are in the same direction. This makes the sum of the expansion force of the first stent 1 and the expansion force of the second stent 2 close to or equal to the pressure applied to the first stent 1 by the blood vessel wall, thereby improving the support force of the first stent 1, or improving the support force of the novel blood flow guiding device of this embodiment.

[0127] In the first prior art, the metal coverage of the vascular stent is limited to a low metal coverage, thereby causing the vascular stent to have low rigidity, resulting in low supporting force of the vascular stent after the vascular stent is placed in a blood vessel and expanded;

[0128] The first stent 1 in this embodiment is equivalent to the first vascular stent in the prior art. Both have low metal coverage, so when the first stent 1 is independently set in the blood vessel, the supporting force is low due to the low rigidity of the first stent 1 itself. However, the second stent 2 in this embodiment is set in the first stent 1, and the expansion force of the second stent 2 increases the supporting force of the first stent 1 itself, or the overlapping structure of the first stent 1 and the second stent 2 increases the supporting force of a new blood flow guiding device in this embodiment.

[0129] In the second prior art, the metal coverage of the intracranial stent is limited to a high metal coverage, thereby increasing the rigidity of the intracranial stent, so that after the intracranial stent is placed in the blood vessel and expanded, the intracranial stent has a high supporting force;

[0130] In this embodiment, after the first stent 1 and the second stent 2 are respectively disposed in a blood vessel, with the second stent 2 disposed within the first stent 1, and the expansion force of the second stent 2 applied to the first stent 1, the first stent 1 and the second stent 2 form an overlapping structure (at least the second overlapping structure C2 described above) with a support force that is close to or reaches the support force of the second prior art intracranial stent;

[0131] However, the structures of the first stent 1 and the second stent 2 of this embodiment are completely different from the structures of the second prior art intracranial stent; the most significant structural difference is that the first stent 1 and the second stent 2 of this embodiment are respectively limited to structures corresponding to low metal coverage, while the intracranial stent of the second prior art is limited to structures corresponding to high metal coverage; in more popular terms, the mesh density of the first stent 1 and the mesh density of the second stent 2 of this embodiment are different from the mesh density of the second prior art intracranial stent.

[0132] In the third prior art, the guide device comprises a distal sparse mesh portion, a central dense mesh portion, and a proximal sparse mesh portion. The distal sparse mesh portion and the proximal sparse mesh portion are each limited to a low metal coverage ratio, resulting in low rigidity and low support force when the distal sparse mesh portion and the proximal sparse mesh portion are located within a blood vessel. The central dense mesh portion is limited to a high metal coverage ratio, resulting in high rigidity and high support force when the central dense mesh portion is located within a blood vessel.

[0133] In this embodiment, the first stent 1 and the second stent 2 are both disposed within a blood vessel, with the second stent 2 disposed within the first stent 1. After the expansion force of the second stent 2 is applied to the first stent 1, the first stents 1 located on both sides of the overlapping position of the first stent 1 and the second stent 2 are equivalent to the distal sparse mesh portion and the proximal sparse mesh portion in the third prior art. The overlapping structure of the first stent 1 and the second stent 2 (at least the second overlapping structure C2 described above) is equivalent to the central dense mesh portion in the third prior art.

[0134] Overall, the supporting force of the novel blood flow guiding device of this embodiment is close to or reaches the supporting force of the guiding device in the third prior art; however, structurally, the structures of the first stent 1 and the second stent 2 in this embodiment (including their own structures and the overall structure after overlapping) are completely different from the structure of the guiding device in the third prior art.

[0135] Therefore, from the perspective of supporting force, the supporting force of the first stent 1 or the second stent 2 in this embodiment itself is the same as that of the vascular stent in the first prior art. However, after the first stent 1 and the second stent 2 in this embodiment form an overlapping structure, the supporting force formed by the two is higher than the supporting force of the vascular stent in the first prior art; after the first stent 1 and the second stent 2 in this embodiment form an overlapping structure, at least the supporting force of the second overlapping structure C2 is close to or reaches the supporting force of the intracranial stent in the second prior art, or, at least the supporting force of the second overlapping structure C2 is close to or reaches the supporting force of the central dense network part in the third prior art.

[0136] Third, from the perspective of the stress of the first bracket 1 and the second bracket 2, stress is the internal force inside an object, which is common knowledge known to those skilled in the art;

[0137] In a scenario where the aneurysm is actually located at a tortuous position of an intracranial artery, the first stent 1 and the second stent 2 of this embodiment are respectively released at the tortuous position of the intracranial artery, wherein a portion of the first stent 1 and the middle section 202 of the second stent 2 should respectively cover the position where the aneurysm communicates with the intracranial artery, so that the second overlapping structure C2 covers the aneurysm to achieve the purpose of treating the aneurysm; wherein the first stent 1 is restricted by the tortuous position of the intracranial artery and bends, so that when the first stent 1 bends, it forms an outer arc portion with a relatively long length and an inner arc portion with a relatively short length; the direction of stress in the outer arc portion is from the middle to the two ends, and the direction of stress in the inner arc portion is from the two ends to the middle;

[0138] Since the first bracket 1 and the second bracket 2 are respectively made by a sparse weaving process, the density of the intersection points of the alloy wires within a unit area of ​​the first bracket 1 and the second bracket 2 is low, which makes the stress distribution of the first bracket 1 and the second bracket 2 itself more uniform, the stress peak of a single intersection point is reduced, and the stress of a single intersection point is dispersed to a larger area.

[0139] Under the condition that only the first stent 1 is set at the tortuous position of the intracranial artery and covers the aneurysm, the first stent 1 is divided into multiple sections along its length direction, and the cross-section of each section (the cross-section is perpendicular to the axis of the first stent 1) has the same or similar area. From the perspective of material mechanics, it can be regarded as that the change in the cross-section area of ​​the previous section and the cross-section area of ​​the latter section is relatively small; the first stent 1 itself is equivalent to the single-layer braided blood flow guide device of the prior art. When the first stent 1 is bent, the stress conduction phenomenon of the first stent 1 (the stress of each alloy wire) can be simplified to the beam structure model in material mechanics; this makes the first stent The stress of the frame 1 (the stress of each alloy wire) is transmitted along the axial direction of the first stent 1. The stress on the cross section of the first section is the same as the stress on the cross section of the second section. In addition, the stresses of the two alloy wires at the intersection are applied or distributed to each other, that is, the stress of one alloy wire is applied or distributed to the other alloy wire. This allows the two alloy wires at the intersection to reduce part of the stress by dissipating energy through the friction between the two alloy wires during the movement (movement caused by stretching due to bending stress). Therefore, the first stent 1 (single-layer braided blood flow guide device) is not prone to stress concentration.

[0140] However, after the first stent 1 is set at the tortuous position of the intracranial artery and covers the aneurysm, the second stent 2 is set at the tortuous position of the intracranial artery, and the second stent 2 is set inside the first stent 1 and covers the aneurysm. Since the second stent 2 applies an expansion force to the first stent 1, the stress of the first stent 1 changes.

[0141] In a hypothetical comparison scenario, the second bracket 2 is assumed to have the same metal coverage ratio for the head section 201, the middle section 202, and the tail section 203, and the first bracket 1 is roughly divided into three sections, namely the first section, the second section, and the third section. The second section completely overlaps with the second bracket 2. In this case, the first section and the third section are not affected by the expansion force of the second bracket 2, while the second section is affected by the expansion force of the second bracket 2.

[0142] In the above hypothetical comparison scheme, for the first bracket 1, since the second section is subjected to the expansion force of the second bracket 2, the shape of the outer arc portion of the current second section changes (this change may be very small and difficult to detect with the naked eye). This change causes the stress of the second section (the direction of the stress of the outer arc portion is along the middle toward the two ends) to change, while the cross-sectional area of ​​the second section remains unchanged; correspondingly, the stress and area of ​​the first section and the third section remain unchanged; the stress of the second section is compared with the stress of the first section and the third section respectively. Obviously, the stress of the second section is different from the stress of the first section and the stress of the third section, respectively. As a result, stress concentration occurs at the intersection of the first section and the second section, and at the intersection of the second section and the third section, respectively.

[0143] In this embodiment, the second bracket 2 is configured as a head section 201, a middle section 202, and a tail section 203, and the metal coverage of the head section 201 and the metal coverage of the tail section 203 are respectively lower than the metal coverage of the middle section 202. The purpose is at least to: by having the metal coverage of the head section 201 and the tail section 203 lower than the metal coverage of the middle section 202, ensure that the expansion force (defined as the first expansion force) exerted by the head section 201 on the first bracket 1 in the first overlapping structure C1 formed with the head section 201 is smaller than the expansion force (defined as the second expansion force) exerted by the middle section 202 on the first bracket 1 in the second overlapping structure C2 formed with the middle section 202, and ensure that the expansion force (defined as the third expansion force) exerted by the tail section 203 on the first bracket 1 in the third overlapping structure C3 formed with the tail section 203 is smaller than the second expansion force;

[0144] Therefore, in this embodiment, the first bracket 1 is actually divided into five sections, see Figure 1 , which are respectively segment A, segment B, segment C, segment D and segment E; wherein segments A to E are arranged in sequence, segment A is equivalent to the first segment in the aforementioned hypothetical comparison scheme, segment E is equivalent to the third segment in the aforementioned hypothetical comparison scheme, and segment C is equivalent to the second segment in the aforementioned hypothetical comparison scheme. Obviously, the difference between the scheme in this embodiment and the aforementioned hypothetical comparison scheme is that it also has segment B and segment D;

[0145] From the perspective of expansion force, the expansion force of section A is the expansion force of the first bracket 1 itself, the expansion force of section B is the sum of the expansion force of the first bracket 1 itself and the first expansion force of the second bracket 2, the expansion force of section C is the sum of the expansion force of the first bracket 1 itself and the second expansion force of the second bracket 2, the expansion force of section D is the sum of the expansion force of the first bracket 1 itself and the third expansion force of the second bracket 2, and the expansion force of section E is the expansion force of the first bracket 1 itself. This results in the actual function of section B being to form a smooth transition buffer structure between sections A and C, or to disperse the stress at the intersection of the first and second sections in the hypothetical comparison scheme to the area where section B is located, so that the stress change is smoother. Correspondingly, the actual function of section D is similar to that of section B. The difference is that section B is located between section C and section E, which will not be repeated here.

[0146] It should be understood that the above-mentioned smooth transition buffer structure is actually achieved by adjusting the number of intersections of the alloy wires within a unit axial length. The change in the number of intersections is due to the addition of alloy wires. The number of intersections is arranged in a direction from section A to section C and in a gradually increasing manner at the position of section B, thereby forming a gradient distribution effect; the effect of this gradient distribution makes the distribution of sections B and D of the first bracket 1 form a rigidity or stress gradient distribution effect, which is beneficial to reducing the stress concentration phenomenon of the first bracket 1.

[0147] The stress concentration between sections A and B is less than the stress concentration between the first and second sections in the aforementioned hypothetical comparative solution. From a material perspective, the stress concentration between sections A and B is weaker, resulting in the stress at the intersection of sections A and B being less likely to reach the yield strength (a technical term in material mechanics) of the material of the first bracket 1.

[0148] Similarly, the stress concentration phenomenon formed between segment B and segment C, the stress concentration phenomenon formed between segment C and segment D, and the stress concentration phenomenon formed between segment D and segment E are respectively smaller than the stress concentration phenomenon formed between the first segment and the second segment in the aforementioned hypothetical comparison scheme, or respectively smaller than the stress concentration phenomenon formed between the second segment and the third segment in the aforementioned hypothetical comparison scheme, resulting in the stress at the intersection of the above-mentioned segments not easily reaching the yield strength of the material of the first bracket 1.

[0149] In the first prior art, the metal coverage of the vascular stent is low, and the density of intersections (intersections formed after the cut metal forms a mesh) per unit area is low;

[0150] In this embodiment, the density of intersection points within a unit area of ​​the first stent 1 and the second stent 2 is the same as or similar to the density of intersection points within a unit area of ​​the vascular stent in the first prior art mentioned above. Therefore, the stress concentration phenomenon of the first stent 1 and the second stent 2 in this embodiment does not exceed the stress concentration phenomenon of the vascular stent in the first prior art.

[0151] In the second prior art, the metal coverage of the intracranial stent is high, and the density of the intersections per unit area is high;

[0152] In this embodiment, the density of intersection points per unit area of ​​the first bracket 1 and the second bracket 2 is lower than the density of intersection points per unit area of ​​the intracranial bracket in the second prior art mentioned above, which makes the stress concentration phenomenon of the first bracket 1 and the second bracket 2 in this embodiment lower than the stress concentration phenomenon of the intracranial bracket in the second prior art.

[0153] In the third prior art, its guide device has a distal sparse mesh part, a central dense mesh part and a proximal sparse mesh part. When the guide device is set at a tortuous position of the intracranial artery, the guide device bends under the influence of the intracranial artery. At this time, the weaving angles of the distal sparse mesh part and the central dense mesh part form a relatively large angle difference, and the weaving angles of the proximal sparse mesh part and the central dense mesh part form a relatively large angle difference. From the perspective of material mechanics, this angle difference leads to discontinuous spatial distribution of Young's modulus, forming a material interface in the sense of material mechanics; the difference in wire diameter or number of adjacent units at the connection causes a step decrease in the moment of inertia of the section, and the stress locally (at the location where the difference in wire number or wire diameter occurs) increases.

[0154] Regarding the third prior art, in layman's terms, due to the sudden change in cross-sectional area at the intersection of the distal sparse mesh portion and the central dense mesh portion, a relatively serious stress concentration phenomenon is formed at the intersection of the distal sparse mesh portion and the central dense mesh portion; similarly, a relatively serious stress concentration phenomenon is also formed at the intersection of the proximal sparse mesh portion and the central dense mesh portion; this relatively serious stress concentration phenomenon is caused by the sudden change in cross-sectional area. During the process of force flow being transmitted from the distal sparse mesh portion or the proximal sparse mesh portion to the central dense mesh portion, stress concentration is formed at the location of the sudden change in cross-sectional area.

[0155] For the third prior art, the relatively serious stress concentration phenomenon makes the stress at the intersection between the distal sparse mesh part and the central dense mesh part, as well as the stress at the intersection between the proximal sparse mesh part and the central dense mesh part, easily reach the yield strength of the material of its guide device.

[0156] It should be understood that before the stress reaches the yield strength, the material itself only produces elastic deformation, so that the material can return to its original shape through its own elastic force after bending or other deformation; after the stress reaches and exceeds the yield strength, the material itself will produce plastic deformation and cannot return to its original shape through its own elastic force. This is common knowledge known to those skilled in the art.

[0157] In a novel blood flow guiding device according to this embodiment, when the first stent 1 is positioned at a tortuous location of an intracranial artery and the second stent 2 is not positioned at a tortuous location of the intracranial artery, the first stent 1 itself does not have a structure that produces a sudden change in cross-sectional area, or a structure that produces a change in stress, thereby reducing stress concentration in the first stent 1. After the first stent 1 and the second stent 2 are simultaneously positioned at the tortuous location of the intracranial artery, the expansion force of the second stent 2 is applied to the first stent 1, causing a change in stress on the first stent 1, but without a change in cross-sectional area or a sudden change in braiding angle.

[0158] Compared to the third prior art, the first bracket 1 of this embodiment reduces stress concentration between two adjacent segments (specifically, any two adjacent segments among segments A to E mentioned above) under conditions of changing force due to the overlapping structures formed by the head segment 201, middle segment 202, and tail segment 203 of the second bracket 2, respectively, and the first bracket 1. The stress at the intersection of the two adjacent segments is unlikely to reach the yield strength of the material of the first bracket 1, and thus the intersection of the two adjacent segments is less likely to fracture.

[0159] In the second bracket 2 of the present embodiment, although the braiding density of the head section 201 and the middle section 202 are different, and the braiding density of the middle section 202 and the tail section 203 are different, the braiding density between the head section 201 and the middle section 202 is changed by increasing the number of alloy wires, and the braiding density between the tail section 203 and the middle section 202 is changed by increasing the number of alloy wires. Therefore, the braiding density of the second bracket 2 is continuously changed, and is not formed by the aforementioned sudden change in the braiding angle; in addition, the braiding angles of the head section 201, the middle section 202 and the tail section 203 of the second bracket 2 do not change.

[0160] The second stent 2 in this embodiment is arranged inside the first stent 1. Since the first stent 1 bears the bending force applied by the tortuous position of the intracranial artery, the first stent 1 rarely applies bending force to the second stent 2. In other words, the bending force applied by the first stent 1 to the second stent 2 is less than the supporting force applied by the second stent 2 to the first stent 1. Therefore, while the second stent 2 plays a role in improving the supporting force of the first stent 1, it reduces the stress concentration of the second stent 2 caused by bending, and avoids the stress at the intersection of the head section 201 and the middle section 202, and the stress at the intersection of the middle section 202 and the tail section 203 from exceeding the yield strength of the material of the second stent 2. In other words, the stress at the intersection of the head section 201 and the middle section 202, and the stress at the intersection of the middle section 202 and the tail section 203 of the second stent 2 are relatively small, so that the intersection of the head section 201 and the middle section 202, and the intersection of the middle section 202 and the tail section 203 only undergo elastic deformation, and no plastic deformation.

[0161] In addition, the impact force exerted by the blood flow in the intracranial artery on the second stent 2 will also cause changes in the stress of the first stent 1 and the second stent 2;

[0162] Specifically, when the impact force of blood flow is applied to the second stent 2, the impact force of blood flow can be regarded as the force applied by the second stent 2 to the first stent 1. This force is defined as the second supporting force. The direction of the second supporting force is the same as the direction of the expansion force applied by the second stent 2 to the first stent 1. As a result, the force applied to the first stent 1 changes again.

[0163] From another perspective, after the impact force of the blood flow is applied to the second stent 2, on the one hand, the low density of the intersection points of the alloy wires per unit area of ​​the second stent 2 causes a portion of the impact force to be converted into stress in the second stent 2 and then dispersed. On the other hand, the overlapping structure formed by the second stent 2 and the first stent 1 causes the impact force of the blood flow to be applied to the first stent 1, forming an interlayer transmission effect. This interlayer transmission effect makes it difficult for the second stent 2 to accumulate stress, which can avoid the negative phenomenon of cumulative fatigue stress or metal fatigue in the second stent 2, and is conducive to improving the service life of the second stent 2.

[0164] When the first bracket 1 produces a stress change due to the effect of layer transmission, the stress of the first bracket 1 is dispersed due to the low density structure of the intersection points of the alloy wires within the unit area of ​​the first bracket 1, thereby reducing the occurrence of stress concentration and avoiding the negative phenomenon of accumulated fatigue stress or metal fatigue in the first bracket 1.

[0165] Therefore, from the perspective of the stress of the first bracket 1 and the second bracket 2, the first overlapping structure C1 and the third overlapping structure C3 formed by the first bracket 1 and the second bracket 2 in this embodiment respectively become buffer structures for the smooth transition of the stress of the first bracket 1, which can also be called a stress gradient distribution structure. Its function is to reduce the stress concentration phenomenon of the first bracket 1 and prevent the stress from reaching the yield strength of the material of the first bracket 1.

[0166] In summary, based on the first, second and third contents mentioned above, the new blood flow guiding device of this embodiment does not solely pursue the metal coverage of the first stent 1 and the second stent 2, nor does it solely pursue the supporting force of the first stent 1 and the second stent 2, nor does it solely pursue reducing the stress concentration phenomenon of the first stent 1 and the second stent 2. Instead, it balances the metal coverage, supporting force and stress concentration phenomenon of the first stent 1 and the second stent 2 to meet the conditions for treating aneurysms and improve safety.

[0167] In addition to the foregoing, in this embodiment, the diameter of the first alloy wire of the first stent 1 is 30 μm, and the diameter of the second alloy wire of the second stent 2 is 30 μm; the first stent 1 and the second stent 2 are woven respectively by a one-press-one-weaving method; the surfaces of the first stent 1 and the second stent 2 are respectively provided with a bionic coating (phosphocholine) to reduce the risk of thrombosis; in addition, the first stent 1 and the second stent 2 of this embodiment are also provided with a developing structure, and the developing structure can adopt a developing point or developing wire structure in the prior art, which will not be repeated here.

[0168] Example 2:

[0169] The novel blood flow guiding device in this embodiment and the novel blood flow guiding device in the aforementioned embodiment 1 have the same technical purpose and achieve the same or similar technical effects, but their technical means are different.

[0170] Specifically, in a novel blood flow guiding device in this embodiment, the metal coverage of the middle section 202 of the second stent 2 is limited to a high metal coverage formed by densely braiding the second alloy wires;

[0171] The diameter of the first alloy wire is the same as the diameter of the second alloy wire;

[0172] The metal coverage of the second overlapping portion is limited to a high metal coverage formed by the overlapping structure of the first bracket 1 with low metal coverage and the middle section 202 with high metal coverage.

[0173] In this embodiment, a novel blood flow guiding device is configured with a high metal coverage of the second stent 2. When the second stent 2 is disposed within the first stent 1, the high metal coverage of the novel blood flow guiding device can be achieved solely through the high metal coverage of the second stent 2.

[0174] At the same time, since the second bracket 2 is limited to a high metal coverage, the expansion force exerted by the second bracket 2 on the first bracket 1 is greater, that is, the supporting force of the second bracket 2 is greater.

[0175] More specifically, in the novel blood flow guiding device of this embodiment, the number of the first alloy wires is 24, and the number of the second alloy wires is 48.

[0176] Among them, this embodiment forms a high metal coverage by increasing the number of second alloy wires; after increasing the number of second alloy wires, the density of the intersection points of the second alloy wires per unit area of ​​the second bracket 2 is high, resulting in a greater supporting force of the second bracket 2.

[0177] The remaining technical solutions and technical effects of this embodiment are the same as or similar to those in the aforementioned embodiment 1 and will not be described in detail here.

[0178] Example 3:

[0179] The novel blood flow guiding device in this embodiment and the novel blood flow guiding device in the aforementioned embodiment and embodiment 2 have the same technical purpose and achieve the same or similar technical effects, but have different technical means.

[0180] Specifically, in a novel blood flow guiding device of this embodiment, the number of first alloy wires is the same as the number of second alloy wires, the diameter of the second alloy wires is greater than the diameter of the first alloy wires, and the number of intersections per unit area of ​​the second alloy wires is the same as the number of intersections per unit area of ​​the first alloy wires, so that the metal coverage of the second stent 2 is different from the metal coverage of the first stent 1, wherein the metal coverage of the second stent 2 is greater than the metal coverage of the first stent 1;

[0181] The metal coverage of the second overlapping portion is limited to a high metal coverage formed by the overlapping structure of the first bracket 1 and the middle section 202 having different metal coverages.

[0182] A new blood flow guiding device in this embodiment limits the metal coverage of the second stent 2 to a high metal coverage by increasing the diameter of the second alloy wire, which results in that when the first stent 1 and the second stent 2 form an overlapping structure, the metal coverage of the second overlapping structure C2 forms a high metal coverage.

[0183] At the same time, since the second bracket 2 is limited to a high metal coverage rate, the expansion force exerted by the second bracket 2 on the first bracket 1 is greater, that is, the supporting force of the second bracket 2 is greater; the actual reason is that the diameter of the second alloy wire is relatively large, resulting in a higher yield strength of the second alloy wire, and thus the supporting force of the second bracket 2 is greater.

[0184] The remaining technical solutions and technical effects of this embodiment are the same as or similar to the technical solutions and technical effects of the aforementioned embodiment 1 or 2, and will not be repeated here.

[0185] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's description and drawings, or directly or indirectly applied to other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A new blood flow guiding device, characterized in that: comprising a first bracket and a second bracket; The first stent and the second stent are both tubular stents made of alloy wires, woven into a diamond-shaped grid structure, and having a self-expanding function. The length of the first stent is greater than the length of the second stent. The alloy wires of the first stent are defined as first alloy wires, and the alloy wires of the second stent are defined as second alloy wires. The second bracket is provided with a head section, a middle section and a tail section, wherein the middle section is located between the head section and the tail section, wherein the number of the second alloy wires in the head section and the number of the second alloy wires in the tail section are respectively smaller than the number of the second alloy wires in the middle section; The metal coverage of the first bracket is configured as low metal coverage; Under the condition that the second bracket is completely disposed in the first bracket, the overlapping structure formed by the first bracket and the head section is defined as a first overlapping structure, the overlapping structure formed by the first bracket and the middle section is defined as a second overlapping structure, and the overlapping structure formed by the first bracket and the tail section is defined as a third overlapping structure; The metal coverage of the first overlapping structure and the metal coverage of the third overlapping structure are respectively greater than the metal coverage of the first bracket and respectively less than the metal coverage of the second overlapping structure. At least the metal coverage of the second overlapping structure is configured as high metal coverage.

2. A novel blood flow guiding device according to claim 1, characterized in that: The metal coverage of the first stent is limited to a low metal coverage formed by sparsely weaving the first alloy wires.

3. A novel blood flow guiding device according to claim 2, characterized in that: The metal coverage of the middle section of the second stent is limited to a low metal coverage formed by sparsely weaving the second alloy wires; The diameter of the first alloy wire is the same as the diameter of the second alloy wire, and there is an angle difference between the braiding angle of the first alloy wire and the braiding angle of the second alloy wire; The metal coverage of the second overlapping structure is limited to a high metal coverage formed by the overlapping structure of the first bracket and the middle section having the angle difference.

4. A novel blood flow guiding device according to claim 3, characterized in that: The number of the first alloy wires and the number of the second alloy wires are 24 respectively; The braiding angle of the first alloy wire is specifically 65 degrees, and the braiding angle of the second alloy wire is specifically 75 degrees.

5. A novel blood flow guiding device according to claim 2, characterized in that: The metal coverage of the middle section of the second stent is limited to a high metal coverage formed by densely braiding the second alloy wires; The diameter of the first alloy wire is the same as the diameter of the second alloy wire; The metal coverage of the second overlapping portion is limited to a high metal coverage formed by the overlapping structure of the first bracket with low metal coverage and the middle section with high metal coverage.

6. A novel blood flow guiding device according to claim 5, characterized in that: The number of the first alloy wires is 24, and the number of the second alloy wires is 48.

7. A novel blood flow guiding device according to claim 2, characterized in that: The number of the first alloy wires is the same as the number of the second alloy wires, the diameter of the second alloy wires is greater than the diameter of the first alloy wires, and the number of intersections per unit area of ​​the second alloy wires is the same as the number of intersections per unit area of ​​the first alloy wires, so that the metal coverage of the second bracket is different from the metal coverage of the first bracket, wherein the metal coverage of the second bracket is greater than the metal coverage of the first bracket; The metal coverage of the second overlapping portion is limited to a high metal coverage formed by the overlapping structure of the first bracket and the middle section having different metal coverages.

8. The novel blood flow guiding device according to claim 1, characterized in that: The high metal coverage is specifically one of the metal coverages between 30% and 35%.

9. The novel blood flow guiding device according to claim 1, characterized in that: Both ends of the first bracket are made by adopting an open weaving process.

10. The novel blood flow guiding device according to claim 1, characterized in that: The first alloy wire and the second alloy wire are respectively made of nickel-titanium alloy.

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