A blood flow diverting device

Abstract

The application relates to the field of medical devices, in particular to a blood flow guiding device which comprises a first stent and a second stent; the second stent is provided with a head section, a middle section and a tail section; the metal coverage of the first stent is configured as low metal coverage; under the condition that the second stent is completely arranged in the first stent, the overlapping structure formed by the first stent and the head section is defined as a first overlapping structure, the overlapping structure formed by the first stent and the middle section is defined as a second overlapping structure, and the overlapping structure formed by the first stent and the tail section is defined as a third overlapping structure; the metal coverage of the first overlapping structure and the third overlapping structure is respectively greater than the metal coverage of the first stent and respectively less than the metal coverage of the second overlapping structure, and at least the metal coverage of the second overlapping structure is configured as high metal coverage. The first stent is limited to low metal coverage, the purpose of improving the passability is achieved, and the supporting force of the first stent is improved through the second stent.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of medical devices, in particular to a blood flow guiding device. BACKGROUND

[0002] The essence of the blood flow guiding device is a vascular stent. In the scenario of applying the blood flow guiding device (stent) to treat intracranial aneurysm, from the perspective of metal coverage, the blood flow guiding device is usually manufactured as: a blood flow guiding device with only low metal coverage, a blood flow guiding device with only high metal coverage, and a blood flow guiding device with both low metal coverage and high metal coverage.

[0003] In the prior art, a patent document with the title of a self-expanding intracranial artery vascular stent (referred to as a vascular stent) and the application number of 201020659175.0 is provided; the vascular stent of the patent document is essentially a blood flow guiding device with low metal coverage;

[0004] The vascular stent is limited to low metal coverage, which results in low rigidity and high flexibility of the vascular stent, so that the passability of the vascular stent in the tortuous position of the intracranial artery (for example, the intracranial artery siphon section) is relatively high, but the low rigidity of the vascular stent results in low support force of the vascular stent in the intracranial artery.

[0005] In the prior art, a patent document with the title of an intracranial stent and an intracranial stent delivery system (referred to as an intracranial stent) and the application number of 202111302295.4 is provided; the intracranial stent of the patent document is essentially a blood flow guiding device with high metal coverage;

[0006] The intracranial stent is limited to high metal coverage, which results in high rigidity and low flexibility of the intracranial stent, and the high rigidity of the intracranial stent results in high support force of the intracranial stent in the intracranial artery, but the passability of the intracranial stent in the tortuous position of the intracranial artery (for example, the intracranial artery siphon section) is relatively low.

[0007] In the prior art, a patent document with the title of a blood flow guiding device applied to treat intracranial aneurysm (referred to as a guiding device) and the application number of 202021228902.8 is provided; the guiding device of the 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 have low metal coverage and high metal coverage at the same time, resulting in the guide device having a structure with low rigidity and a structure with high rigidity at the same time, the structure with high rigidity of the guide device resulting in high support force of the guide device in the intracranial artery, and the structure with low rigidity of the guide device being beneficial to improve the flexibility of the guide device, but the passability of the guide device in the tortuous position (for example, the intracranial artery siphon section) of the intracranial artery is affected by the structure with high rigidity of the guide device, resulting in the phenomenon of relatively low passability;

[0009] In addition, the guide device described above has a stress concentration phenomenon when it is specifically arranged at the tortuous position of the intracranial artery.

[0010] Therefore, how to make the blood flow guide device have relatively high passability at the tortuous position of the intracranial artery, and the blood flow guide device have relatively high support force in the intracranial artery, while also reducing the stress concentration phenomenon, becomes a technical problem to be solved. SUMMARY

[0011] To solve the technical problem of how to make the blood flow guide device have relatively high passability at the tortuous position of the intracranial artery, and the blood flow guide device have relatively high support force in the intracranial artery, while also reducing the stress concentration phenomenon, the present application provides a blood flow guide device.

[0012] To achieve the above-mentioned object, the technical scheme adopted by the present application is as follows:

[0013] According to one aspect of the present application, a blood flow guide device is provided, comprising a first stent and a second stent;

[0014] The first stent and the second stent are respectively tubular stents made of alloy wires and woven into a diamond mesh structure, and have a self-expanding function, the length of the first stent is greater than the length of the second stent, wherein the alloy wire of the first stent is defined as a first alloy wire, and the alloy wire of the second stent is defined as a second alloy wire;

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

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

[0017] Under the condition that the second stent is completely arranged in the first stent, two ends of the first stent do not overlap with two ends of the second stent, an overlapping structure composed of the first stent and the head section is defined as a first overlapping structure, an overlapping structure composed of the first stent and the middle section is defined as a second overlapping structure, and an overlapping structure composed of the first stent and the tail section is defined as a third overlapping structure;

[0018] The weaving angle of the first alloy wire and the weaving angle of the second alloy wire have an angle difference, 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 stent and respectively less than the metal coverage of the second overlapping structure, and at least the metal coverage of the second overlapping structure is configured as a high metal coverage.

[0019] Further, the metal coverage of the first stent is limited to a low metal coverage formed by the first alloy wire in a sparse weaving manner.

[0020] Further, the metal coverage of the middle section of the second stent is limited to a low metal coverage formed by the second alloy wire in a sparse weaving manner.

[0021] The diameter of the first alloy wire and the diameter of the second alloy wire are the same.

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

[0023] Further, the number of the first alloy wires and the number of the second alloy wires are respectively 24.

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

[0025] Further, the metal coverage of the middle section of the second stent is limited to a high metal coverage formed by the second alloy wire in a dense weaving manner.

[0026] The diameter of the first alloy wire and the diameter of the second alloy wire are the same.

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

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

[0029] Further, the number of the first alloy wires and the number of the second alloy wires are the same, the diameter of the second alloy wires is greater than the diameter of the first alloy wires, and the number of the intersection points per unit area of the second alloy wires is the same as the number of the intersection points per unit area of the first alloy wires, so that the metal coverage of the second stent is different from the metal coverage of the first stent, and the metal coverage of the second stent is greater than the metal coverage of the first stent.

[0030] The metal coverage of the second overlapping structure is limited to a high metal coverage formed by overlapping of the first stent and the middle segment with different metal coverages.

[0031] Further, the high metal coverage is between 30% and 35%.

[0032] Further, the two ends of the first stent are made by using an open weaving process.

[0033] Further, the first alloy wires and the second alloy wires are respectively made of a nickel-titanium alloy.

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

[0035] The blood flow guiding device provided by the application limits the first stent to a low metal coverage, achieves the purpose of improving the passability, improves the support of the first stent through the second stent, forms the first overlapping structure and the third overlapping structure with the head segment and the tail segment of the second stent respectively, so that the stress of the first stent can be distributed in the length direction of the first stent through the first overlapping structure and the third overlapping structure, and the first stent and the second stent are woven into a rhombus grid structure, so that the number of intersection points of the alloy wires per unit area of the two is reduced under the condition of the low metal coverage, and the stress of the intersection points is dispersed to a relatively large area. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 A structure schematic view of a blood flow guiding device provided by an embodiment of the application;

[0037] Figure 2 A structure schematic view of a first stent provided by an embodiment of the application;

[0038] Figure 3 A structure schematic view of a second stent provided by an embodiment of the application;

[0039] Figure 4 A schematic view of a weaving angle provided by an embodiment of the application. DETAILED DESCRIPTION Embodiment 1

[0040] In the embodiment, a blood flow guiding device is provided to solve the technical problem of how to make the blood flow guiding device have relatively high passability at a tortuous position of an intracranial artery and have relatively high support in the intracranial artery, while also being able to reduce stress concentration.

[0041] Specifically, referring to Figures 1 to 3 The blood flow guiding device of the embodiment includes a first stent 1 and a second stent 2.

[0042] The first stent 1 and the second stent 2 are tubular stents made of alloy wires and woven into a diamond mesh structure and have a self-expanding function. The length of the first stent 1 is greater than the length 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.

[0043] The second stent 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 of the head section 201 and the number of second alloy wires of the tail section 203 are less than the number of second alloy wires of the middle section 202.

[0044] The metal coverage of the first stent 1 is configured as low metal coverage.

[0045] Under the condition that the second stent 2 is completely arranged in the first stent 1, the two ends of the first stent 1 do not overlap with the two ends of the second stent 2. The overlapping structure formed by the first stent 1 and the head section 201 is defined as a first overlapping structure C1. The overlapping structure formed by the first stent 1 and the middle section 202 is defined as a second overlapping structure C2. The overlapping structure formed by the first stent 1 and the tail section 203 is defined as a third overlapping structure C3.

[0046] The weaving angle of the first alloy wires and the weaving angle of the second alloy wires have an angle difference. 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 stent 1 and respectively 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.

[0047] In the embodiment, the metal coverage of the first stent 1 is configured as low metal coverage, so that the first stent 1 has relatively high flexibility. At the same time, because the metal coverage of the first stent 1 is low metal coverage, the rigidity of the first stent 1 is relatively low. In other words, the elastic force of the first stent 1 itself is relatively low.

[0048] In the embodiment, the metal coverage of the second stent 2 is configured as low metal coverage, so that the second stent 2 has relatively high flexibility; at the same time, due to the low metal coverage of the second stent 2, the rigidity of the second stent 2 is relatively low, in other words, the self-elastic force of the second stent 2 is relatively low.

[0049] Since the first stent 1 and the second stent 2 are respectively limited to 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 blood flow guiding device of the embodiment exerting greater elastic force on the inner wall of the intracranial artery when arranged in the intracranial artery.

[0050] In the embodiment, the material of the first stent 1 and the material of the second stent 2 respectively adopt alloy wires as the material; wherein the alloy wire of the first stent 1 is defined as the first alloy wire, and the alloy wire of the second stent 2 is defined as the second alloy wire, and the first alloy wire and the second alloy wire can be configured as the same material or different materials.

[0051] In the embodiment, preferably, the first alloy wire and the second alloy wire are configured as the same material; specifically, the first alloy wire and the second alloy wire are respectively preferably made of a nickel-titanium alloy material.

[0052] It should be understood that the nickel-titanium alloy material is one of the commonly used materials for manufacturing vascular stents (blood flow guiding devices), which is the common knowledge of those skilled in the art and will not be described here.

[0053] It should be understood that in other embodiments, the first alloy wire and the second alloy wire can also be configured as different materials, for example: the first alloy wire is configured as a nickel-titanium alloy material, and the second alloy wire is configured as a cobalt-chromium alloy or a platinum-tungsten alloy, but the rigidity of these two materials is higher than that of the nickel-titanium alloy. The flexibility of the second stent 2 made of cobalt-chromium alloy or platinum-tungsten alloy is significantly reduced, so that the passability through the tortuous position of the intracranial artery is lower than that of the second stent 2 made of nickel-titanium alloy.

[0054] In the embodiment, the metal coverage of the first stent 1 is limited to low metal coverage formed by using the sparse weaving method for the first alloy wire.

[0055] The opposite method of the sparse weaving method is the dense weaving method, and the specific weaving process of the sparse weaving method and the dense weaving method is the common knowledge of those skilled in the art, which will not be described here.

[0056] In the embodiment, the first plurality of alloy wires of the first stent 1 are woven in a sparse weaving manner, and the mesh size of the first stent 1 is relatively large; compared with the first reference stent woven in a dense weaving manner, the mesh size of the first reference stent is relatively small;

[0057] In the embodiment, the mesh size of the first stent 1 is relatively large, which leads to that the rigidity of the first stent 1 is relatively low, or in other words, the elasticity of the first stent 1 is relatively low; compared with the first reference stent woven in a dense weaving manner, the mesh size of the first reference stent is relatively small, which leads to that the rigidity of the first reference stent is relatively high, or in other words, the elasticity of the first reference stent is relatively high.

[0058] In the embodiment, the metal coverage of the middle section 202 of the second stent 2 is limited to a low metal coverage formed by the second plurality of alloy wires woven in a sparse weaving manner;

[0059] The diameter of the first plurality of alloy wires is the same as the diameter of the second plurality of alloy wires;

[0060] The metal coverage of the second overlapping structure C2 is limited to a high metal coverage formed by the overlapping structure of the first stent 1 and the middle section 202 having an angle difference.

[0061] In the embodiment, the weaving manner of the second stent 2 is the same as the weaving manner of the first stent 1, both of which are the sparse weaving manner, and the diameter of the second plurality of alloy wires of the second stent 2 is the same as the diameter of the first plurality of alloy wires of the first stent 1, so that the metal coverage of the second stent 2 is also a low metal coverage, which is the same as or close to the low metal coverage of the first stent 1.

[0062] In the embodiment, since the second plurality of alloy wires of the second stent 2 are woven in a sparse weaving manner, the mesh size of the second stent 2 is relatively large, which leads to that the rigidity of the second stent 2 is relatively low, or in other words, the elasticity of the second stent 2 is relatively low.

[0063] In the foregoing, it has been proposed that when the second stent 2 is arranged in the first stent 1, the metal coverage of at least the second overlapping structure C2 is a high metal coverage; the high metal coverage of the second overlapping structure C2 is formed by the first stent 1 with a low metal coverage and the second stent 2 with a low metal coverage being overlapped with each other, and the weaving angle of the first plurality of alloy wires of the first stent 1 is different from the weaving angle of the second plurality of alloy wires of the second stent 2;

[0064] Specifically, the weaving angle of the first plurality of alloy wires of the first stent 1 is defined as a first angle, the weaving angle of the second plurality of alloy wires of the second stent 2 is defined as a second angle, and the first angle and the second angle have an angle difference; see Figure 1When the second support 2 is arranged in the first support 1, a part of the first alloy wires of the first support 1 covers a part of the mesh holes of the diamond mesh structure of the second support 2 along the radial direction of the first support 1, and a part of the second alloy wires of the second support 2 covers a part of the mesh holes of the diamond mesh structure of the first support 1. Overall, the first alloy wires of the first support 1 and the second alloy wires of the second support 2 are in a staggered position relationship, so that when a person views the second overlapping structure C2 along the radial direction of the first support 1, the mesh holes of the diamond mesh structure of the first support 1 are covered by the second alloy wires to form a mesh hole reduction phenomenon, and correspondingly, the mesh holes of the diamond mesh structure of the second support 2 are covered by the first alloy wires to form a mesh hole reduction phenomenon. Therefore, the metal coverage of the second overlapping structure C2 changes from the low metal coverage of the first support 1 and the low metal coverage of the second support 2 to high metal coverage.

[0065] In the embodiment, referring to 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 support 1;

[0066] Specifically, referring to Figures 1 to 3 , the first overlapping structure C1 is formed by overlapping a part of the first support 1 and the head section 201 of the second support 2, and in the first overlapping structure C1, the weaving angle of the first alloy wires of the first support 1 is different from the weaving angle of the second alloy wires of the head section 201 of the second support 2, so that a part of the first alloy wires cover the mesh holes of the diamond mesh structure of the head section 201 of the second support 2, and a part of the second alloy wires of the head section 201 of the second support 2 cover the mesh holes of the diamond mesh structure of the first support 1, so that the metal coverage of the first overlapping structure C1 is higher than the metal coverage of the first support 1;

[0067] At the same time, referring to Figures 1 to 3 , since the number of the second alloy wires of the head section 201 of the second support 2 is less than the number of the second alloy wires of the middle section 202 of the second support 2, the size of the mesh holes of the diamond mesh structure of the head section 201 of the second support 2 is greater than the size of the mesh holes of the diamond mesh structure of the middle section 202 of the second support 2, which makes the mesh holes of the diamond mesh of the first support 1 appear two phenomena:

[0068] The first phenomenon is that the number of the mesh holes of the diamond mesh structure of the first support 1 covered by the second alloy wires of the head section 201 of the second support 2 in the first overlapping structure C1 is less than the number of the mesh holes of the diamond mesh structure of the first support 1 covered by the second alloy wires of the middle section 202 of the second support 2 in the second overlapping structure C2;

[0069] For example, in the first overlapping structure C1, along the circumferential direction, the number of the mesh holes of the diamond mesh structure of the first stent 1 is 10 (this is a hypothetical number, not used to limit the blood flow guide device of the present embodiment), then the second alloy wires of the head section 201 of the second stent 2 cover 5 of the 10 mesh holes (this is a hypothetical number, not used to limit the blood flow guide device of the present embodiment);

[0070] Correspondingly, in the second overlapping structure C2, along the circumferential direction, the number of the mesh holes of the diamond mesh structure of the first stent 1 is 10 (this is a hypothetical number, not used to limit the blood flow guide device of the present embodiment), then the second alloy wires of the middle section 202 of the second stent 2 cover all the 10 mesh holes (this is a hypothetical number, not used to limit the blood flow guide device of the present embodiment);

[0071] Since the number of the mesh holes of the first stent 1 covered by the second alloy wires of the head section 201 of the second stent 2 is less than the number of the mesh holes of the first stent 1 covered by the second alloy wires of the middle section 202 of the second stent 2, the metal coverage of the first overlapping structure C1 is less than the metal coverage of the second overlapping structure C2.

[0072] The second phenomenon, “in the first overlapping structure C1, the number of the mesh holes of the diamond mesh structure of the first stent 1 covered by the second alloy wires of the head section 201 of the second stent 2”, is equal to “in the second overlapping structure C2, the number of the mesh holes of the diamond mesh structure of the first stent 1 covered by the second alloy wires of the middle section 202 of the second stent 2”, but “in the first overlapping structure C1, the number of the second alloy wires of the head section 201 of the second stent 2 used to cover the mesh holes of the first stent 1”, is less than “in the second overlapping structure C2, the number of the second alloy wires of the middle section 202 of the second stent 2 used to cover the mesh holes of the first stent 1”;

[0073] For example: in the first overlapping structure C1, along the circumferential direction, the number of the mesh holes of the diamond mesh structure of the first stent 1 is 10 (this is a hypothetical number, not used to limit the blood flow guide device of the present embodiment), then the second alloy wires of the head section 201 of the second stent 2 cover all the 10 mesh holes (this is a hypothetical number, not used to limit the blood flow guide device of the present embodiment), but each mesh hole of the first stent 1 is covered by one second alloy wire respectively (this is a hypothetical number, not used to limit the blood flow guide device of the present embodiment);

[0074] Correspondingly, in the second overlapping structure C2, along the circumferential direction, the number of mesh holes of the rhombic mesh structure of the first stent 1 is 10 (this is a hypothetical number, which does not limit the blood flow guiding device of the embodiment), then, the second alloy wires of the middle section 202 of the second stent 2 cover all the 10 mesh holes (this is a hypothetical number, which does not limit the blood flow guiding device of the embodiment), but each mesh hole of the first stent 1 is covered by two or three second alloy wires respectively (this is a hypothetical number, which does not limit the blood flow guiding device of the embodiment);

[0075] Since the number of second alloy wires used to cover the mesh holes of the first stent 1 in the first overlapping structure C1 is less than the number of second alloy wires used to cover the mesh holes of the first stent 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.

[0076] Similarly, the structure of the third overlapping structure C3 is the same as that of the first overlapping structure C1, the metal coverage of the third overlapping structure C3 is the same or similar to that of the first overlapping structure C1, and the principle of the metal coverage of the third overlapping structure C3 is described above. The principle of the first overlapping structure C1 will not be repeated here.

[0077] In the embodiment, the number of first alloy wires and the number of second alloy wires are 24 respectively;

[0078] The weaving angle of the first alloy wire is specifically 65 degrees, and the weaving angle of the second alloy wire is specifically 75 degrees.

[0079] The blood flow guiding device of the embodiment is made of 24 first alloy wires by weaving process, and the second stent 2 is made of 24 first alloy wires by weaving process, which makes the metal coverage of the first stent 1 and the metal coverage of the second stent 2 form low metal coverage respectively; When the second stent 2 is arranged in the first stent 1, the sum of the number of first alloy wires and second alloy wires of the second overlapping structure is 48.

[0080] The structure of the first stent 1 and the structure of the second stent 2 are different;

[0081] Specifically, along the length direction of the first stent 1, the first stent 1 is divided into several sections, and the number of first alloy wires of any two adjacent sections of the first stent 1 is the same; and the number of first alloy wires of the first stent 1 is limited to 24.

[0082] Referring to Figures 1 to 3, along the length direction of the second stent 2, the second stent 2 is divided into the aforementioned head section 201, middle section 202 and tail section 203, wherein the number of the second alloy wires of the head section 201 is less than the number of the second alloy wires of the middle section 202, and the number of the second alloy wires of the tail section 203 is less than the number of the second alloy wires of the middle section 202;

[0083] 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 set in a manner of gradually increasing the number of the wires, for example: if the number of the second alloy wires of the head section 201 is 5 (this is a hypothetical number, not used to limit the blood flow guiding device of the embodiment) and if the number of the second alloy wires of the middle section 202 is 10 (this is a hypothetical number, not used to limit the blood flow guiding device of the 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 a hypothetical number, not used to limit the blood flow guiding device of the embodiment), so that the number of the second alloy wires of the head section 201 is configured to be 5 alloy wires at the end, 6 or 7 alloy wires between the end and the intersection of the middle section 202 (the number of the second alloy wires of the head section 201 is 5, plus 1 or 2 second alloy wires), 11 or 12 alloy wires from the intersection of the end and the middle section 202 to the middle position of the middle section 202 (the number of the second alloy wires of the middle section 202 is 10, plus 1 or 2 second alloy wires), and the number of the second alloy wires of the whole middle section 202 is described below, which is not mentioned here;

[0084] Correspondingly, along the direction from the tail section 203 to the middle section 202, the number of the second alloy wires is configured to be the same or similar to the number of the second alloy wires in the aforementioned "along the direction from the head section 201 to the middle section 202", which is not described here.

[0085] It is worth noting that, due to the increase in the number of the second alloy wires 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 aforementioned manner of increasing the number of the second alloy wires is formed, so that the number of the second alloy wires of the middle section 202 is also increased, and the number of the second alloy wires of the middle section 202 is the sum of the aforementioned number of the second alloy wires, the number of the second alloy wires added by the head section 201, and the number of the second alloy wires added by the tail section 203; and the number of the second alloy wires of the middle section 202 of the second stent 2 in the embodiment is limited to 24.

[0086] It has been mentioned in the foregoing that the weaving angle of the first alloy wire and the weaving angle of the second alloy wire have an angle difference, and the purpose is to make the first stent 1 and the second stent 2 jointly form a high metal coverage;

[0087] In the embodiment, the weaving angle of the first alloy wire is 65 degrees, and the weaving angle of the second alloy wire is 75 degrees, which makes the weaving angle of the first alloy wire and the weaving angle of the second alloy wire form an angle difference;

[0088] In the known prior art, there are two expressions of weaving angle, respectively,

[0089] The first expression of the weaving angle: taking the axial line direction of the blood flow guiding device as the reference, taking the angle (which can be acute or obtuse) formed by a single wire relative to the axial line direction as the weaving angle;

[0090] The second expression of the weaving angle (see Figure 4 ): taking the diameter direction of the blood flow guiding device as the reference, taking the angle (which can be acute or obtuse) formed by a single wire relative to the diameter direction as the weaving angle.

[0091] The weaving angle mentioned in the technical solution of the embodiment should be understood according to the second expression of the weaving angle.

[0092] The weaving angle has a significant influence on the radial support force, the radial resilience rate and other parameters of the single-layer woven blood flow guiding device of the blood flow guiding device, but this is not the emphasis of the technical solution of the embodiment; in the technical solution of the embodiment, more emphasis is placed on the fact that the weaving angle of the first alloy wire and the weaving angle of the second alloy wire are not the same, so that the first stent 1 and the second stent 2 can change the metal coverage after overlapping.

[0093] The weaving angle of the first alloy wire of the first stent 1 is relatively small, and the purpose is to improve the flexibility of the first stent 1 and improve the porosity of the first stent 1. This setting can reduce the area of the first stent 1 covering the branch blood vessels (bifurcated blood vessels);

[0094] The weaving angle of the second alloy wire of the second stent 2 is relatively large, and the purpose is to improve the support 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 position of the aneurysm and the intracranial artery, the second stent 2 can enhance the blood flow retention effect.

[0095] When the second stent 2 is arranged in the first stent 1, the positional relationship between the first alloy wire and the second alloy wire of the first overlapping structure C1 is that, due to the angles of the first alloy wire and the second alloy wire of the first overlapping structure C1 being different, the first alloy wire can cover the mesh holes of the diamond mesh structure of the second stent 2, and the second alloy wire can cover the mesh holes of the diamond mesh structure of the first stent 1; in other words, the first alloy wire and the second alloy wire do not overlap each other.

[0096] When the second stent 2 is arranged in the first stent 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 the same as or similar to the positional relationship between the first alloy wire and the second alloy wire of the first overlapping structure C1 described above, which will not be described here.

[0097] Further, the blood flow guiding device of the embodiment has a high metal coverage rate of 30% to 35%.

[0098] Generally, in the field, a metal coverage rate equal to or greater than 30% is considered as a high metal coverage rate.

[0099] On the one hand, whether it is a blood flow guiding device of the prior art or a blood flow guiding device of the embodiment, the essence is to reduce the blood flow into the aneurysm, so a high metal coverage rate represents that the density of the blood flow guiding device between the blood flow and the aneurysm is high, and a low metal coverage rate (a metal coverage rate below 30%) represents that the density of the blood flow guiding device between the blood flow and the aneurysm is low, and a person skilled in the art can easily understand that a high-density blood flow guiding device blocks more blood flow, and a low-density blood flow guiding device blocks less blood flow.

[0100] On the other hand, whether it is a blood flow guiding device of the prior art or a blood flow guiding device of the embodiment, the essence is to change the direction of the blood flow in the aneurysm artery to reduce or weaken the blood flow impact in the aneurysm, so as to achieve the purpose of blood retention and thrombosis in the aneurysm; finally, new endothelial cells are formed on the surface of the blood flow guiding device and at the neck of the aneurysm, so as to achieve complete closure and cure of the aneurysm.

[0101] Based on the above two reasons, for the blood flow guiding device of the embodiment, it is not that the higher the metal coverage rate is, the better, but to limit the metal coverage rate within a reasonable range, especially to limit the high metal coverage rate within a reasonable range; in the embodiment, a metal coverage rate of 35% is one of the high metal coverage rates, and is the highest metal coverage rate that the inventors of the present application believe to limit the high metal coverage rate of the blood flow guiding device of the embodiment within a reasonable range.

[0102] Since the high metal coverage is limited to a metal coverage of 30% to 35%, restrictions are made on the metal coverage of the first stent 1 itself and the metal coverage of the second stent 2 itself respectively; the metal coverage of the first stent 1 itself is not the high metal coverage, and the metal coverage of the first stent 1 itself is not the lower the better, but should be limited within a reasonable range; similarly, the metal coverage of the second stent 2 itself should be limited within a reasonable range, so as to cooperate with the angle difference formed by the weaving angles of the first alloy wire and the second alloy wire to finally form the high metal coverage (one of the metal coverages of 30% to 35%) of the blood flow guiding device of the embodiment.

[0103] It should be understood that the metal coverage of the first stent 1 and the metal coverage of the second stent 2 can be obtained by a limited number of manufacturing, as long as the metal coverage of the overlapping structure (at least the second overlapping structure C2) of the two is one of the aforementioned metal coverages of 30% to 35% when the second stent 2 is arranged inside the first stent 1.

[0104] It should be understood that the method for measuring the metal coverage of the blood flow guiding device is known to those skilled in the art, and will not be described here.

[0105] Further, referring to Figures 1 to 3 The two ends of the first stent 1 of the blood flow guiding device of the embodiment are made of an open weaving process.

[0106] The open weaving process is known to those skilled in the art, and the specific structure of the two ends of the first stent 1 made of the open weaving process is known to those skilled in the art; for example: in the prior art with the title 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 woven open loop structure, which is essentially a structure made of an open weaving process.

[0107] It should be understood that the open weaving process corresponds to the closed weaving process; in the embodiment, the open weaving process is used, so that the two ends of the first stent 1 are in a dispersed state under the natural state by the elastic force of the first stent 1 itself; in some prior art, the guiding device made of the closed weaving process has a ring structure at its two ends, which is not the dispersed state of the two ends of the first stent 1 of the embodiment.

[0108] In the embodiment, the two ends of the first stent 1 are made by an open weaving process, which aims 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. In other words, when the rigidity of the first stent 1 at the two ends is lower than the rigidity of the first stent 1 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 between the two ends, which makes the first stent 1 at the two ends more easily deformed when subjected to external force (such as resistance from the inner wall of the artery), thereby improving the passability of the first stent 1.

[0109] It should be noted that the blood flow guiding device of the embodiment is not simply configured as a sleeving structure of two stents.

[0110] First, from the perspective of passability, the essence is the difficulty of the first stent 1 and the second stent 2 to pass through or reach the tortuous position of the intracranial artery in sequence.

[0111] In the embodiment, the first stent 1 and the second stent 2 are respectively pushed to the tortuous position of the intracranial artery or pass through the tortuous position of the intracranial artery by using a pushing mechanism of the prior art, wherein the pushing mechanism at least includes a catheter for limiting the movement path of the first stent 1 and the second stent 2, and includes a receiving structure for receiving 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 receiving structure and outside the catheter, and a guide wire for limiting the first stent 1 or the second stent 2 relative to the catheter. These are common knowledge known to those skilled in the art, and the principle will not be described again.

[0112] In the embodiment, before the first stent 1 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, and the other end of the catheter is located outside the human body for operation by medical personnel.

[0113] Then, the first stent 1 is arranged in the catheter and is 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 in the catheter.

[0114] When the first stent 1 approaches the tortuous position of the intracranial artery, the catheter located at the tortuous position of the intracranial artery is bent due to the influence of the tortuous position of the intracranial artery on the catheter itself, which causes the first stent 1 to be resisted by the inner wall of the catheter when passing through the bent position of the catheter. The resistance causes the first stent 1 to elastically deform and bend; the shape of the first stent 1 after bending is similar to the current bending shape of the catheter, so that the first stent 1 can smoothly pass through the bent position of the catheter by continuing to push the first stent 1.

[0115] In the first prior art (named a self-expanding intracranial artery blood vessel stent, application number 201020659175.0), the metal coverage of the blood vessel stent is low, so that the rigidity of the blood vessel stent is relatively low and the flexibility is relatively high. The blood vessel stent with higher flexibility is more likely to pass through the tortuous position of the intracranial artery.

[0116] The first stent 1 in the embodiment is configured to have low metal coverage, so it has the same or similar flexibility as the first prior art. Therefore, the passability of the first stent 1 in the embodiment is the same or similar to that of the blood vessel stent in the first prior art.

[0117] In the second prior art (named an intracranial stent and an intracranial stent delivery system, application number 202111302295.4), the metal coverage of the intracranial stent is high, resulting in higher rigidity and lower flexibility of the intracranial stent. The blood vessel stent with lower flexibility is not easy to pass through the tortuous position of the intracranial artery, so the passability of the intracranial stent is low.

[0118] The metal coverage of the first stent 1 in the embodiment is lower than that of the second prior art, so the rigidity of the first stent 1 in the embodiment is lower than that of the intracranial stent in the second prior art, and the flexibility of the first stent 1 in the embodiment is higher than that of the intracranial stent in the second prior art. Therefore, the passability of the first stent 1 in the embodiment is higher.

[0119] In the third prior art (a blood flow guiding device applied to treat intracranial aneurysm, application number 202021228902.8), the stent in the guiding 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 metal coverage, the central dense mesh portion is directly connected with the distal sparse mesh portion and the proximal sparse mesh portion, and the metal coverage of the central dense mesh portion is high metal coverage, which makes the rigidity of the central dense mesh portion high and the flexibility low. The central dense mesh portion with low flexibility is not easy to pass through the tortuous position of the intracranial artery, so the passability of the guiding device is low.

[0120] Compared with the third prior art, the metal coverage of the first stent 1 in the embodiment is completely limited to low metal coverage, so the rigidity of the first stent 1 in the embodiment is lower than that of the central dense mesh portion of the guiding device of the third prior art. The flexibility of the first stent 1 in the embodiment is higher than that of the central dense mesh portion of the third prior art, so the passability of the first stent 1 in the embodiment is higher.

[0121] Therefore, from the perspective of passability, the passability of the first stent 1 in the embodiment is the same as or similar to that of the stent (or device) in the prior art which is limited to low metal coverage, and is higher than that of the stent (or device) in the prior art which is completely limited to high metal coverage, or higher than that of the stent (or device) in the prior art which has partial high metal coverage. The high passability of the first stent 1 can make the first stent 1 more easily pass through the tortuous position of the intracranial artery and reach a deeper position of the intracranial artery.

[0122] The second stent 2 in the embodiment is also limited to low metal coverage, so the rigidity, flexibility and passability of the second stent 2 are equivalent or similar to those of the first stent 1, which will not be described here.

[0123] Second, from the perspective of support force, the essence of support force is the resistance of the stent in the blood vessel to the pressure of the blood vessel wall. When a stent is arranged in the blood vessel, whether the stent is self-expandable or expanded by a balloon, after the stent is expanded, it will inevitably be subjected to the pressure of the blood vessel wall, which can force the expanded stent to shrink. If the support force of a stent is low, the diameter of the expanded stent will be lower than the ideal diameter after the stent is expanded in the blood vessel and subjected to the pressure of the blood vessel wall. Conversely, if the support force of a stent is high, the diameter of the expanded stent will be close to or reach the ideal diameter after the stent is expanded in the blood vessel and subjected to the pressure of the blood vessel wall.

[0124] The first stent 1 in the embodiment is manufactured by sparse weaving process, and the metal coverage of the first stent 1 is limited to low metal coverage, which results in low rigidity of the first stent 1 itself, so that when the first stent 1 is arranged in the blood vessel, the supporting force of the first stent 1 is low;

[0125] Therefore, in order to improve the supporting force of the first stent 1, or in order to improve the supporting force of the blood flow guiding device in the embodiment, the overlapping structure formed by arranging the second stent 2 in the first stent 1 is adopted in the embodiment; wherein, after the first stent 1 is arranged in the blood vessel, the second stent 2 is arranged in the first stent 1, so that the second stent 2 is expanded by self-expansion; after the second stent 2 is expanded, the second stent 2 contacts the first stent 1; from the force bearing angle of the first stent 1, on the one hand, the outer wall of the first stent 1 is subjected to the pressure of the blood vessel wall, so that the first stent 1 has a contraction trend, on the other hand, the inner wall of the first stent 1 is subjected to the expansion force of the self-expansion of the second stent 2, so that the first stent 1 has an expansion trend; and the expansion force of the self-expansion of the first stent 1 and the expansion force of the self-expansion of the second stent 2 are in the same direction, which 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 of the blood vessel wall on the first stent 1, so as to improve the supporting force of the first stent 1, or improve the supporting force of the blood flow guiding device in the embodiment.

[0126] In the first prior art, the metal coverage of the vascular stent is limited to low metal coverage, so that the rigidity of the vascular stent is low, which results in that the supporting force of the vascular stent is low after the vascular stent is arranged in the blood vessel and expanded;

[0127] The first stent 1 in the embodiment corresponds to the vascular stent in the first prior art, and the metal coverage of both is low metal coverage, so that when the first stent 1 is arranged in the blood vessel independently, the supporting force is low due to the low rigidity of the first stent 1 itself, but the second stent 2 in the embodiment is arranged in the first stent 1, the expansion force of the second stent 2 improves the supporting force of the first stent 1 itself, or the overlapping structure of the first stent 1 and the second stent 2 improves the supporting force of the blood flow guiding device in the embodiment.

[0128] In the second prior art, the metal coverage of the intracranial stent is limited to high metal coverage, so that the rigidity of the intracranial stent is high, which results in that the supporting force of the intracranial stent is high after the intracranial stent is arranged in the blood vessel and expanded;

[0129] The first stent 1 and the second stent 2 in the embodiment form the support force of the overlapping structure (at least the second overlapping structure C2 in the foregoing) of the first stent 1 and the second stent 2 after being respectively arranged in the blood vessel and the second stent 2 being arranged in the first stent 1 and the expansion force of the second stent 2 being applied to the first stent 1, which is close to or reaches the support force of the second prior art intracranial stent;

[0130] However, the structure of the first stent 1 and the second stent 2 in the embodiment is completely different from the structure of the second prior art intracranial stent; the most significant structural difference is that the first stent 1 and the second stent 2 in the embodiment are respectively limited to the structure corresponding to the low metal coverage, while the second prior art intracranial stent is limited to the structure corresponding to the high metal coverage; more popularly speaking, the mesh density of the first stent 1 and the mesh density of the second stent 2 in the embodiment are different from the mesh density of the second prior art intracranial stent.

[0131] In the third prior art, the guide device has a distal sparse mesh portion, a central dense mesh portion and a proximal sparse mesh portion; wherein the distal sparse mesh portion and the proximal sparse mesh portion are respectively limited to low metal coverage, resulting in low rigidity of the two, so that the support force of the two is low when they are located in the blood vessel; and the central dense mesh portion is limited to high metal coverage, so that the rigidity of the central dense mesh portion is high, and then the support force of the central dense mesh portion is high when the central dense mesh portion is located in the blood vessel;

[0132] The first stent 1 and the second stent 2 in the embodiment are arranged in the blood vessel, and the second stent 2 is arranged in the first stent 1, and after the expansion force of the second stent 2 is applied to the first stent 1, the first stent 1 located on both sides of the overlapping position of the first stent 1 and the second stent 2 is equivalent to the distal sparse mesh portion and the proximal sparse mesh portion in the third prior art, and the overlapping structure (at least the second overlapping structure C2 in the foregoing) of the first stent 1 and the second stent 2 is equivalent to the central dense mesh portion in the third prior art;

[0133] Overall, the support force of the blood flow guide device in the embodiment is close to or reaches the support force of the guide device in the third prior art; however, in terms of structure, the structure (including the structure of the two themselves and the overall structure after overlapping) of the first stent 1 and the second stent 2 in the embodiment is completely different from the structure of the guide device in the third prior art.

[0134] Therefore, from the perspective of the support force, the support force of the first stent 1 or the second stent 2 in the embodiment itself is the same as that of the first prior art vascular stent, but after the first stent 1 and the second stent 2 form the overlapping structure, the support force formed by the two together is higher than that of the first prior art vascular stent; after the first stent 1 and the second stent 2 form the overlapping structure, the support force of at least the second overlapping structure C2 approaches or reaches the support force of the second prior art intracranial stent, or the support force of at least the second overlapping structure C2 approaches or reaches the support force of the central dense mesh portion of the third prior art.

[0135] Thirdly, from the perspective of the stress of the first stent 1 and the second stent 2, stress is the internal force inside an object, which is common knowledge known by those skilled in the art;

[0136] In the scenario where the aneurysm actually locates at a tortuous position of the intracranial artery, the first stent 1 and the second stent 2 of the embodiment are respectively released at the tortuous position of the intracranial artery, wherein one part 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 bent due to the limitation of the tortuous position of the intracranial artery, so that the first stent 1 forms a relatively long outer arc portion and a relatively short inner arc portion when it is bent; the stress direction of the outer arc portion is along the direction from the middle to the two ends, and the stress direction of the inner arc portion is along the direction from the two ends to the middle;

[0137] Since the first stent 1 and the second stent 2 are respectively made by using the sparse weaving process, the density of the intersection points of the alloy wires in the unit area of the first stent 1 and the second stent 2 is low, which makes the stress distribution of the first stent 1 itself and the second stent 2 itself more uniform, the stress peak value of a single intersection point is reduced, and the stress of a single intersection point is dispersed to a larger area.

[0138] In the condition that only the first stent 1 is arranged at the tortuous position of the intracranial artery and covers the aneurysm, the first stent 1 is divided into multiple sections along the length direction thereof, and the area of the cross section of each section (the cross section is perpendicular to the axis of the first stent 1) is the same or similar. From the perspective of material mechanics, the change amount of the area of the cross section of the previous section and the area of the cross section of the next section is small. The first stent 1 itself is equivalent to the single-layer braided blood flow guiding device in the prior art. When the first stent 1 is bent, the stress (stress of each alloy wire) conduction phenomenon of the first stent 1 can be simplified as a beam structure model in material mechanics. This makes the stress (stress of each alloy wire) of the first stent 1 transfer along the axial direction of the first stent 1, and the stress received by the cross section of the previous section is the same as the stress received by the cross section of the next section. In addition, the stress of the two alloy wires at the intersection point is applied to or distributed to each other, that is, the stress of one alloy wire is applied to or distributed to the other alloy wire. This makes the two alloy wires at the intersection point reduce a part of the stress by dissipating energy through the friction force between the two alloy wires in the process of generating movement (movement generated by the stretching of the bending stress). Therefore, the first stent 1 (single-layer braided blood flow guiding device) is not prone to stress concentration phenomenon.

[0139] However, in the condition that the first stent 1 is arranged at the tortuous position of the intracranial artery and covers the aneurysm, and then the second stent 2 is arranged at the tortuous position of the intracranial artery and arranged in the first stent 1 and covers the aneurysm, the stress of the first stent 1 changes due to the expansion force applied by the second stent 2 to the first stent 1.

[0140] In a hypothetical comparative scheme, the second stent 2 is assumed to have the same metal coverage as the head section 201, the middle section 202 and the tail section 203, and the first stent 1 is roughly divided into three sections, which are the first section, the second section and the third section. The second section completely overlaps the second stent 2. In this case, the first section and the third section are not subjected to the expansion force of the second stent 2, and the second section is subjected to the expansion force of the second stent 2.

[0141] In the above-mentioned hypothetical comparative scheme, for the first support 1, due to the second section being subjected to the expansion force of the second support 2, the shape of the outer arc portion of the current second section is changed (this change can be very small and not easy to be perceived by the naked eye), which leads to a change in the stress of the second section (the direction of the stress of the outer arc portion is along the middle to the ends), while the cross-sectional area of the second section remains unchanged; correspondingly, the stresses and areas of the first section and the third section remain unchanged; comparing the stress of the second section with the stresses of the first section and the third section respectively, it is obvious that the stress of the second section is different from the stresses of the first section and the third section respectively, thereby forming stress concentration phenomena at the intersections of the first section and the second section and at the intersections of the second section and the third section respectively.

[0142] In the present embodiment, the second support 2 is provided as the head section 201, the middle section 202 and the 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, and the purposes thereof at least include: through the scheme that the metal coverage of the head section 201 and the tail section 203 is lower than the metal coverage of the middle section 202, the expansion force (defined as the first expansion force) applied by the first support 1 in the first overlapping structure C1 formed with the head section 201 is less than the expansion force (defined as the second expansion force) applied by the first support 1 in the second overlapping structure C2 formed with the middle section 202, and the expansion force (defined as the third expansion force) applied by the first support 1 in the third overlapping structure C3 formed with the tail section 203 is less than the second expansion force;

[0143] Therefore, in the present embodiment, the first support 1 is actually divided into five sections, which are the A section, the B section, the C section, the D section and the E section, as shown in Figure 1 , wherein the A to E sections are sequentially arranged, the A section corresponds to the first section in the above-mentioned hypothetical comparative scheme, the E section corresponds to the third section in the above-mentioned hypothetical comparative scheme, and the C section corresponds to the second section in the above-mentioned hypothetical comparative scheme, and it is obvious that the difference between the scheme in the present embodiment and the above-mentioned hypothetical comparative scheme is that the B section and the D section are further provided;

[0144] From the perspective of expansion force, the expansion force of section A is the expansion force of the first stent 1 itself, the expansion force of section B is the sum of the expansion force of the first stent 1 itself and the first expansion force of the second stent 2, the expansion force of section C is the sum of the expansion force of the first stent 1 itself and the second expansion force of the second stent 2, the expansion force of section D is the sum of the expansion force of the first stent 1 itself and the third expansion force of the second stent 2, and the expansion force of section E is the expansion force of the first stent 1 itself, which leads to the fact that the actual role of section B is to form a smooth transition buffer structure between sections A and C, or to disperse the stress at the intersection of the first section and the second section in the hypothetical comparative scheme into the area where section B is located, so that the change of stress is more gentle. Correspondingly, the actual role of section D is similar to that of section B, except that section B is located between sections C and E, which will not be described here.

[0145] It should be understood that the smooth transition buffer structure described above is essentially achieved by adjusting the number of intersection points of alloy wires within a unit axial length. The change in the number of intersection points is due to the increase in alloy wires. The number of intersection points is gradually increased in the direction from section A to section C and at the position of section B, thereby forming a gradient distribution effect. This gradient distribution effect causes the distribution of sections B and D of the first stent 1 to form a gradient distribution of rigidity or stress, which is beneficial to reducing the stress concentration phenomenon of the first stent 1.

[0146] The stress concentration phenomenon formed between sections A and B is smaller than the stress concentration phenomenon formed between the first section and the second section in the aforementioned hypothetical comparative scheme. From the perspective of materials, the stress concentration phenomenon formed between sections A and B is weaker, which causes the stress at the intersection of sections A and B to not easily reach the yield strength of the material of the first stent 1 (a special term in material mechanics).

[0147] Similarly, the stress concentration phenomenon between sections B and C, the stress concentration phenomenon between sections C and D, and the stress concentration phenomenon between sections D and E are respectively smaller than the stress concentration phenomenon between the first section and the second section in the aforementioned hypothetical comparative scheme, or respectively smaller than the stress concentration phenomenon between the second section and the third section in the aforementioned hypothetical comparative scheme, which causes the stress at the intersection between the above sections to not easily reach the yield strength of the material of the first stent 1.

[0148] In the first prior art, the metal coverage of the vascular stent is low metal coverage, and the density of intersection points (intersection points after the cut metal forms a mesh) in a unit area is low.

[0149] In the embodiment, the density of intersection points in the unit area of the first stent 1 and the second stent 2 is the same as or similar to the density of intersection points in the unit area of the vascular stent in the first prior art, so that the stress concentration phenomenon of the first stent 1 and the second stent 2 in the embodiment does not exceed the stress concentration phenomenon of the vascular stent in the first prior art.

[0150] In the second prior art, the metal coverage of the intracranial stent is high metal coverage, and the density of intersection points in the unit area is high.

[0151] In the embodiment, the density of intersection points in the unit area of the first stent 1 and the second stent 2 is lower than the density of intersection points in the unit area of the intracranial stent in the second prior art, which makes the stress concentration phenomenon of the first stent 1 and the second stent 2 in the embodiment lower than the stress concentration phenomenon of the intracranial stent in the second prior art.

[0152] In the third prior art, the guide device has a distal sparse network portion, a central dense network portion and a proximal sparse network portion, respectively. When the guide device is arranged 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 network portion and the central dense network portion form a relatively large angle difference, and the weaving angles of the proximal sparse network portion and the central dense network portion also form a relatively large angle difference. From the perspective of material mechanics, such 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 position causes a step drop in the sectional moment of inertia, and the stress at the local position (where the number of wires or wire diameter differs) increases.

[0153] For the third prior art, in a popular way, due to the intersection of the distal sparse network portion and the central dense network portion, the cross-sectional area changes suddenly, resulting in a relatively serious stress concentration phenomenon at the intersection of the distal sparse network portion and the central dense network portion; similarly, at the intersection of the proximal sparse network portion and the central dense network portion, a relatively serious stress concentration phenomenon is also formed; such relatively serious stress concentration phenomenon is caused by the sudden change of cross-sectional area, and stress concentration is formed at the position of sudden change of cross-sectional area in the process of force flow transmission from the distal sparse network portion or the proximal sparse network portion to the central dense network portion.

[0154] For the third prior art, the relatively serious stress concentration phenomenon makes the stress at the intersection between the distal sparse network portion and the central dense network portion, and the stress at the intersection between the proximal sparse network portion and the central dense network portion, respectively, easily reach the yield strength of the material of the guide device.

[0155] It should be understood that before the stress reaches the yield strength, the material itself only produces elastic deformation, so that the material can restore to its original shape by 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 restore to its original shape by its own elastic force, which is known to those skilled in the art.

[0156] The blood flow guiding device of the embodiment, when the first stent 1 is arranged at the tortuous position of the intracranial artery and the second stent 2 is not arranged at the tortuous position of the intracranial artery, the first stent 1 itself does not have a structure that causes a sudden change in cross-sectional area, or the first stent 1 itself does not have a structure that causes a change in stress, so that the stress concentration phenomenon of the first stent 1 is relatively low; after the first stent 1 and the second stent 2 are arranged at the tortuous position of the intracranial artery at the same time, the expansion force of the second stent 2 is applied to the first stent 1, so that the first stent 1 causes a change in stress, but the first stent 1 does not cause a change in cross-sectional area, nor a sudden change in weaving angle;

[0157] The first stent 1 in the embodiment, relative to the third prior art described above, under the condition of a change in stress, the overlapping structure formed by the head segment 201, the middle segment 202 and the tail segment 203 of the second stent 2 with the first stent 1 respectively, causes the stress concentration phenomenon between the two adjacent segments (specifically, any two adjacent segments in the A to E segments described above) to be reduced, and the stress at the intersection of the two adjacent segments is not easy to reach the yield strength of the material of the first stent 1, so that the intersection of the two adjacent segments is not easy to break;

[0158] The second stent 2 in the embodiment, although the weaving density of the head segment 201 and the middle segment 202 is different, and the weaving density of the middle segment 202 and the tail segment 203 is different, the weaving density between the head segment 201 and the middle segment 202 is changed by increasing the number of alloy wires, and the weaving density between the tail segment 203 and the middle segment 202 is changed by increasing the number of alloy wires, so that the weaving density of the second stent 2 is continuously changed, rather than being formed by the sudden change in the weaving angle described above; in addition, the weaving angle of the head segment 201, the middle segment 202 and the tail segment 203 of the second stent 2 does not change.

[0159] The second stent 2 in the embodiment is arranged inside the first stent 1. Since the first stent 1 bears the bending force exerted by the tortuous position of the intracranial artery, the first stent 1 rarely exerts bending force on the second stent 2. In other words, the bending force exerted by the first stent 1 on the second stent 2 is smaller than the support force exerted by the second stent 2 on the first stent 1. Thus, the second stent 2 plays a role in improving the support force of the first stent 1, and at the same time, reduces the stress concentration phenomenon of the second stent 2 caused by bending, avoids the stress at the intersection of the head section 201 and the middle section 202, and avoids the stress at the intersection of the middle section 202 and the tail section 203, which exceeds 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 of the second stent 2, and the stress at the intersection of the middle section 202 and the tail section 203 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 have elastic deformation, but no plastic deformation.

[0160] In addition, the impact force of the blood flow in the intracranial artery on the second stent 2 also causes changes in the stress of the first stent 1 and the second stent 2;

[0161] Specifically, when the impact force of the blood flow is exerted on the second stent 2, the impact force of the blood flow can be regarded as the force exerted by the second stent 2 on the first stent 1. This force is defined as the second support force. The direction of the second support force is the same as the direction of the expansion force exerted by the second stent 2 on the first stent 1. Thus, the stress on the first stent 1 changes again.

[0162] In other words, after the impact force of the blood flow is exerted on the second stent 2, on the one hand, the low-density structure of the intersection points of the alloy wires in the unit area of the second stent 2 causes a part of the impact force to be dispersed after being converted into the stress of the second stent 2. 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 exerted on the first stent 1, forming a layer-to-layer transmission effect. This layer-to-layer transmission effect makes the second stent 2 not easy to accumulate stress, avoids the negative phenomenon of the second stent 2 forming cumulative fatigue stress or metal fatigue, and is beneficial to improving the service life of the second stent 2.

[0163] When the first stent 1 changes in stress through the layer-to-layer transmission effect, the low-density structure of the intersection points of the alloy wires in the unit area of the first stent 1 causes the stress of the first stent 1 to be dispersed, reduces the occurrence of stress concentration, and avoids the negative phenomenon of the first stent 1 accumulating fatigue stress or metal fatigue.

[0164] Therefore, from the perspective of stress of the first stent 1 and the second stent 2, the first stent 1 and the second stent 2 in the embodiment, the first overlapping structure C1 and the third overlapping structure C3 formed by the first stent 1 and the second stent 2, respectively, become a buffer structure for smooth transition of stress of the first stent 1, which can also be called a stress gradient distribution structure, and the function of the buffer structure is to reduce the stress concentration phenomenon of the first stent 1 and avoid the stress reaching the yield strength of the material of the first stent 1.

[0165] In summary, from the first, second and third contents described above, the blood flow guiding device in the embodiment is not a single pursuit of the metal coverage of the first stent 1 and the second stent 2, nor a single pursuit of the support force of the first stent 1 and the second stent 2, nor a single pursuit of reducing the stress concentration phenomenon of the first stent 1 and the second stent 2, but the metal coverage, the support force and the stress concentration phenomenon of the first stent 1 and the second stent 2 are balanced to meet the conditions for treating aneurysm and improve safety.

[0166] In addition to the foregoing, in the 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 respectively woven into a press-braided structure; the surfaces of the first stent 1 and the second stent 2 are respectively provided with a biomimetic coating (phosphorylcholine) to reduce the risk of thrombosis; in addition, the first stent 1 and the second stent 2 of the embodiment are also provided with a developing structure, which can adopt the developing point or developing wire structure in the prior art, which will not be described here. Embodiment 2

[0167] The blood flow guiding device in the embodiment has the same technical purpose as the blood flow guiding device in the foregoing embodiment 1, achieves the same or similar technical effects, and has differences in technical means.

[0168] Specifically, in the blood flow guiding device in the embodiment, the metal coverage of the middle segment 202 of the second stent 2 is limited to a high metal coverage formed by densely braiding the second alloy wire;

[0169] The diameter of the first alloy wire is the same as the diameter of the second alloy wire;

[0170] The metal coverage of the second overlapping structure is limited to a high metal coverage formed by overlapping the first stent 1 with low metal coverage and the middle segment 202 with high metal coverage.

[0171] The metal coverage of the second stent 2 is configured as high metal coverage in the blood flow guiding device of the embodiment, so that when the second stent 2 is arranged in the first stent 1, the high metal coverage of the blood flow guiding device of the embodiment is formed only by the high metal coverage of the second stent 2.

[0172] At the same time, since the second stent 2 is limited to high metal coverage, the expansion force of the second stent 2 applied to the first stent 1 is greater, that is, the support force of the second stent 2 is greater.

[0173] More specifically, the number of first alloy wires of the blood flow guiding device of the embodiment is 24, and the number of second alloy wires is 48.

[0174] Among them, the high metal coverage of the embodiment is formed 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 in the unit area of the second stent 2 is high, resulting in a greater support force of the second stent 2.

[0175] The remaining technical solutions and technical effects of the embodiment are the same as or similar to the technical solutions and technical effects of the aforementioned embodiment 1, and will not be described here. Embodiment 3

[0176] The blood flow guiding device of the embodiment is the same as the blood flow guiding devices of the aforementioned embodiments and embodiment 2 in terms of technical purpose and technical effects, and the technical means of the three is different.

[0177] Specifically, the number of first alloy wires and the number of second alloy wires of the blood flow guiding device of the embodiment are the same, the diameter of the second alloy wire is greater than the diameter of the first alloy wire, and the number of intersection points per unit area of the second alloy wire is the same as the number of intersection points per unit area of the first alloy wire, so that the metal coverage of the second stent 2 is not the same as 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.

[0178] The metal coverage of the second overlapping structure is limited to high metal coverage formed by overlapping the first stent 1 and the middle section 202 having different metal coverages.

[0179] The blood flow guiding device of the embodiment limits the metal coverage of the second stent 2 to high metal coverage by increasing the diameter of the second alloy wire, which results in the metal coverage of the second overlapping structure C2 being high metal coverage when the first stent 1 and the second stent 2 form an overlapping structure.

[0180] At the same time, since the second support 2 is limited to high metal coverage, so that the second support 2 exerts greater expansion force on the first support 1, that is, the support force of the second support 2 is greater; the essential reason is that the diameter of the second alloy wire is relatively large, which leads to higher yield strength of the second alloy wire, so that the support force of the second support 2 is greater.

[0181] The remaining technical solutions and technical effects of the embodiment are the same as or similar to those of the technical solutions and technical effects in the aforementioned embodiments 1 or 2, and will not be described here.

[0182] The above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application, any equivalent structural transformation made by using the content of the specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A blood flow diverting device, comprising: The first stent and the second stent are respectively a tubular stent with a diamond mesh structure and a self-expanding function, which is made of alloy wires as materials, and the length of the first stent is greater than the length of the second stent, wherein 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 stent is provided with a head section, a middle section and a tail section, and the middle section is located between the head section and the tail section, wherein the number of the second alloy wires of the head section and the number of the second alloy wires of the tail section are respectively less than the number of the second alloy wires of the middle section. The metal coverage of the first stent is configured as a low metal coverage. Under the condition that the second stent is completely arranged in the first stent, the two ends of the first stent do not overlap with the two ends of the second stent, the overlapping structure composed of the first stent and the head section is defined as a first overlapping structure, the overlapping structure composed of the first stent and the middle section is defined as a second overlapping structure, and the overlapping structure composed of the first stent and the tail section is defined as a third overlapping structure. The weaving angles of the first alloy wires and the second alloy wires have an angle difference, the metal coverages of the first overlapping structure and the third overlapping structure are respectively greater than the metal coverage of the first stent and respectively less than the metal coverage of the second overlapping structure, and at least the metal coverage of the second overlapping structure is configured as a high metal coverage. The metal coverage of the first stent is limited to a low metal coverage formed by the first alloy wires using a sparse weaving method.

2. A blood flow diverting device according to claim 1, wherein, The metal coverage of the middle section of the second stent is limited to a low metal coverage formed by the second alloy wires using a sparse weaving method.

3. A blood flow diverting device according to claim 2, wherein, The diameters of the first alloy wires and the second alloy wires are the same. The metal coverage of the second overlapping structure is limited to a high metal coverage formed by the overlapping structure of the first stent and the middle section with the angle difference. The number of the first alloy wires and the number of the second alloy wires are respectively 24.

4. A blood flow diverting device according to claim 3, wherein, The weaving angle of the first alloy wires is specifically 65 degrees, and the weaving angle of the second alloy wires is specifically 75 degrees. The metal coverage of the middle section of the second stent is limited to a high metal coverage formed by the second alloy wires using a dense weaving method.

5. A blood flow diverting device according to claim 2, wherein, The diameters of the first alloy wires and the second alloy wires are the same. The metal coverage of the second overlapping structure is limited to a high metal coverage formed by the overlapping of the first stent with a low metal coverage and the middle section with a high metal coverage. The number of the first alloy wires is 24, and the number of the second alloy wires is 48.

6. A blood flow diverting device according to claim 5, wherein, ​ 7. A blood flow diverting device as in claim 2, wherein, 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 larger 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 is different from the metal coverage of the first stent, wherein the metal coverage of the second stent is greater than the metal coverage of the first stent. The metal coverage of the second overlapping structure is limited to a high metal coverage formed by overlapping the first stent and the middle section with different metal coverages.

8. The blood flow diverting device of claim 1, wherein, The high metal coverage is between 30% and 35%.

9. The blood flow diverting device of claim 1, wherein, The two ends of the first stent are made by an open weaving process.

10. The blood flow diverting device of claim 1, wherein, The first alloy wires and the second alloy wires are respectively made of nickel-titanium alloy.

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