CN113017945B

CN113017945B - Vascular intervention stent

Info

Publication number: CN113017945B
Application number: CN201911360869.6A
Authority: CN
Inventors: 谢志永; 刘子昂; �田�浩
Original assignee: Microport Neurotech Shanghai Co Ltd
Current assignee: Microport Neurotech Shanghai Co Ltd
Priority date: 2019-12-25
Filing date: 2019-12-25
Publication date: 2024-01-23
Anticipated expiration: 2039-12-25
Also published as: CN113017945A

Abstract

The invention relates to an intravascular interventional stent which is mainly applied to filtering of intracranial blood vessels, can realize the aim of filtering emboli of the intracranial blood vessels for a long time, and is convenient for other interventional medical instruments to realize interventional treatment of other parts of the blood vessels through the stent, thereby improving the disease treatment effect. The vascular intervention stent comprises a supporting structure and a filtering structure, wherein the supporting structure is tubular, the filtering structure is a net-shaped structure and is connected with the supporting structure, the filtering structure is provided with a closed state and an open state, when the filtering structure is configured to be subjected to the action of external force along the axial direction of the vascular intervention stent, the filtering structure is converted into the open state from the closed state, and when the filtering structure is further configured to release the action of external force, the filtering structure is converted into the closed state from the open state.

Description

Vascular intervention stent

Technical Field

The invention relates to the technical field of medical appliances, in particular to a vascular intervention stent.

Background

Emboli from the heart and aorta occlude cerebral blood supply arteries, which can cause transient ischemic attacks (Transient Ischemic Attack, TIA) and strokes. In China, about half of the emboli of patients suffering from acute ischemic stroke (Acute Ischemic Stroke, AIS for short) are derived from the heart. Atrial fibrillation, left ventricular thrombosis, dilated cardiomyopathy, rheumatic valvular disease, prosthetic heart valve, heart failure, and myocardial infarction in the near future in high risk patients may all cause emboli. According to the national institutes of health (national institutes of health, NIH) stroke database, about 60% of all strokes are caused by embolism, and 14% -30% of ischemic strokes are caused by cardiac embolism. Even if the race escapes from the first AIS stroke, it is difficult to ensure that the next cerebral blood supply artery occlusion does not occur.

Patients with atrial fibrillation, who currently have a history of stroke or TIA from a source of heart embolism, should receive lifelong anticoagulation therapy. However, the most important risk of anticoagulant therapy is bleeding complications, especially intracranial bleeding, which, once bleeding, can cause death or disability. However, the bleeding risk associated with anticoagulant therapy can be circumvented by interventional therapy. In interventional therapy, only the thrombus taking stent or the carotid stent is generally used for filtering broken plaque or thrombus at the same time, and the distal protection umbrella is taken out after the operation is finished and does not have the capability of filtering the thrombus for a long time. Other intracranial vascular stents are even more free of the ability to filter emboli. Moreover, the existing intravascular filter device has the following problems and is not suitable for intracranial blood vessels:

1. the mesh of the filter screen is larger, the filtering capability is insufficient, the anchoring force is lower, and the filter screen cannot adapt to intracranial blood vessels with faster blood flow velocity and smaller emboli;

2. the intracranial vascular access has complex tortuosity, the intervention operation has higher difficulty, and a surgical instrument is needed to pass through for the second time sometimes, but the fully-closed filter device cannot meet the requirement;

3. the filtering device and the anchoring device are mutually independent and are required to be assembled in certain connection modes, the intracranial intervention device is extremely small in size and high in assembly difficulty, the risk of assembly failure can be introduced, and meanwhile, the whole device is relatively large in size;

4. periodic recovery is required, otherwise thrombus can be caused, but intracranial surgery is difficult and risky, and is not suitable for multiple operations.

Disclosure of Invention

The invention provides a vascular intervention stent, which can avoid anticoagulant drug treatment and intracranial hemorrhage risks caused by the anticoagulant drug treatment, and also allows other intervention medical instruments to pass through the part implanted with the stent, so that other intervention treatments are convenient to perform, and the disease treatment effect is improved.

The vascular intervention support comprises a supporting structure and a filtering structure, wherein the supporting structure is tubular, and the filtering structure is of a net structure and is connected with the supporting structure; the filter structure has a closed state and an open state;

the filtering structure is configured to transition from the closed state to the open state when subjected to an external force in an axial direction of the vascular access stent; the filter structure is further configured to transition from the open state to the closed state upon release of the external force.

Optionally, the filtering structure comprises a plurality of filtering rods, at least part of the first ends of the filtering rods are connected with the supporting structure, and at least part of the second ends of the filtering rods are suspended;

the second ends of the hanging arrangement are mutually close and overlap joint to realize the closing of the filtering structure; and when the filtering structure is acted by the external force, the second ends of the hanging arrangement are separated from each other so that the filtering structure is opened, and when the filtering structure releases the external force, the second ends of the hanging arrangement are mutually closed and overlapped.

Optionally, the first ends of the filter rods are arranged along the circumference of the support structure.

Optionally, the first end of each filter rod is connected with the supporting structure, the second end of each filter rod is suspended, and the second ends of all filter rods are mutually close and overlap.

Optionally, the filter rods are radially arranged on a plane, radially arranged on a three-dimensional plane or arranged on a chessboard.

Optionally, when the filter rods are arranged in a three-dimensional radial manner, the filter structure is dome-shaped or cone-shaped.

Optionally, the first part of the filter rods extends along a first direction, the second part of the filter rods extends along a second direction, and the first direction and the second direction form a preset angle, so that the filter rods are arranged in a plane chessboard shape.

Optionally, among all the filter rods extending along the first direction, two ends of the shorter filter rods are connected with the supporting structure, and the first ends of the longer filter rods are connected with the supporting structure, and the second ends of the longer filter rods are suspended;

among all the filter rods extending along the second direction, two ends of the filter rods with shorter lengths are connected with the supporting structure, first ends of the filter rods with longer lengths are connected with the supporting structure, and second ends of the filter rods extending along the first direction are suspended and mutually close to and overlap with second ends of the suspended filter rods.

Optionally, among all the filter rods suspended at the second end, a projection length of at least a part of the filter rods on a radial plane of the supporting structure meets the following requirements:

D/2≤L≤D

wherein: l is the projection length, and D is the diameter of the support structure after expansion.

Optionally, the filtering structure is disposed at one end of the support structure;

the entire length of the filter structure does not overlap the support structure in the axial direction of the support structure, or the entire length of the filter structure at least partially overlaps the support structure in the axial direction of the support structure.

Optionally, the filtering structure and the supporting structure are integrally formed.

Optionally, the filtering structure and the supporting structure are integrally woven by woven wires, or the filtering structure and the supporting structure are integrally cut by laser.

Optionally, the supporting structure is in a net pipe shape and comprises a plurality of supporting rods, the diameter of the supporting structure after expansion is 3.0-6.0 mm, and the included angle between the supporting rods and the radial cross section of the supporting structure is 10-45 degrees.

Optionally, the diameter of the expanded supporting structure is 3.0-4.5 mm, and the included angle between the supporting rod and the radial cross section of the supporting structure is 30-35 degrees; or the diameter of the support structure after expansion is 4.5-5.5 mm, and the included angle between the support rod and the radial cross section of the support structure is 20-25 degrees; or the diameter of the support structure after expansion is 5.5-6.0 mm, and the included angle between the support rod and the radial cross section of the support structure is 10-15 degrees.

Optionally, the material of the support structure and/or the filter structure is nickel-titanium alloy, cobalt-chromium alloy, stainless steel, polylactic acid or magnesium alloy.

Optionally, the filter structure comprises a number of filter mesh openings, the maximum width of the filter mesh openings not exceeding 0.2mm.

Optionally, a plurality of the filter mesh openings are distributed along the circumference of the support structure, and the maximum width of the filter mesh openings along the circumference is not more than 0.2mm.

Optionally, the plurality of filter cells are distributed along a first direction and a second direction, and the maximum width of the filter cells is not more than 0.2mm, and the first direction and the second direction are arranged at a preset angle.

Optionally, the maximum width of the filter mesh is 0.15 mm-0.2 mm.

Optionally, the vascular intervention stent is an intracranial vascular intervention stent.

Alternatively, when the external force applied to the filter structure is released, the filter structure is changed from the open state to the closed state by the self-resilience force.

The vascular intervention stent achieves the purpose of filtering emboli in blood vessels, particularly intracranial blood vessels, for a long time through the supporting structure and the filtering structure, can replace anticoagulation treatment to prevent AIS, and avoids intracranial hemorrhage risks caused by anticoagulation treatment. Meanwhile, the filtering structure can be opened when the external force acts on the filtering structure, so that other interventional medical instruments such as a catheter, other stents and the like are allowed to pass through the vascular interventional stent of the invention for the second time, the filtered thrombus is conveniently treated by the suction catheter, the thrombus taking device and the like, the interventional therapy is also conveniently carried out on other parts of the blood vessel, the disease treatment effect is further improved, meanwhile, a doctor is allowed to carry out more complex operation, and the operation effect is improved. However, after external force is removed, the filtering structure can automatically recover to a closed state to filter the emboli, so that the normal embolic filtering capability of the vascular interventional stent is not affected, and the use is convenient. And anchor fixedly in the blood vessel through being tubular bearing structure, anchor strong ability, anchoring effect is good, makes this blood vessel intervene the support and need not to set up extra anchor again and just can adapt to the circumstances that blood flow velocity is faster, can ensure the vascular intervention support fixed steadiness, uses safe and reliable. Moreover, the filtering structure is an opening structure, is easier to deform when being pressed and held, is convenient to enter the conveying sheath after being pressed and held, and avoids the problem that the filtering structure cannot rebound due to overlarge plastic deformation.

The vascular intervention stent is of an integrated structure, such as an integrated cutting or braiding structure, is beneficial to controlling the overall size of the vascular intervention stent, is convenient to convey in tiny blood vessels, avoids the risk of connection failure during assembly of split molding, and improves the reliability and safety of products.

The filtering structure of the vascular intervention stent uses the filtering mesh with the maximum width not exceeding 0.2mm, is favorable for capturing finer emboli and has good filtering effect.

The vascular intervention stent can be made of biodegradable materials, so that secondary operation is avoided, thrombus risks caused by permanent implantation are avoided, operation risks caused by stent recovery are also avoided, and operation safety is improved.

Drawings

Fig. 1a is a front view of a vascular interventional stent according to a first embodiment of the present invention;

FIG. 1b is an axial cross-sectional view of a vascular access stent provided in a first embodiment of the present invention;

FIG. 1c is a top view of a vascular access stent provided in a first embodiment of the present invention;

fig. 2a is a front view of a vascular intervention stent provided in a second embodiment of the present invention;

fig. 2b is an axial cross-sectional view of a vascular access stent provided by a second embodiment of the present invention;

fig. 2c is a top view of a vascular access stent provided by a second embodiment of the present invention;

fig. 3a is a front view of a vascular intervention stent provided in a third embodiment of the present invention;

FIG. 3b is an axial cross-sectional view of a vascular access stent provided by a third embodiment of the present invention;

fig. 3c is a top view of a vascular intervention stent provided in a third embodiment of the present invention.

In the figure:

10. 20, 30-vascular intervention stents;

1. 3, 5-support structure;

11. 31, 51-supporting rods;

2. 4, 6-filtration;

21. 41, 61-filter rods;

the projected length of the L-filter rod;

maximum width of W-filter mesh;

and an included angle between the alpha-supporting rod and the radial cross section of the supporting structure.

The use of different reference numbers in the figures indicates identical or similar items.

Detailed Description

The invention will be further described in detail with reference to the accompanying drawings, in order to make the objects, advantages and features of the invention more apparent. It should be noted that the drawings are in a very simplified form and are all to a non-precise scale, merely for convenience and clarity in aiding in the description of embodiments of the invention.

As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise. The term "plurality" is generally employed in its sense including two or more unless the content clearly dictates otherwise. The term "plurality" is used generally in a sense including an indefinite number unless the content clearly indicates otherwise. The term "proximal" generally refers to the end that is operated proximal to the medical device and "distal" refers to the end that is operated distal to the medical device, unless the context clearly indicates otherwise

The core idea of the invention is to provide a vascular interventional stent which is particularly suitable for blood vessels with complex vascular access and smaller vessel diameters, such as intracranial blood vessels. The vascular access stent includes a support structure and a filter structure. In particular, by arranging a structural design of the filtering structure capable of being opened at one end of the tubular supporting structure, when the filtering structure is implanted in a blood vessel but not opened, emboli can be filtered normally through the filtering structure, and when the filtering structure is opened under the action of external force exerted by other interventional medical devices (such as a catheter or a guide wire) and the like, other interventional medical devices are allowed to pass through the vascular part implanted in the vascular interventional stent, so that interventional treatment is conveniently carried out at other parts of the blood vessel at the same time or the interventional treatment of various devices is carried out at the same part, the disease treatment effect can be improved, and meanwhile, a doctor is allowed to carry out more complex operation, and the operation efficiency is improved. However, after the external force of other interventional medical devices is removed, the filtering structure can be restored to the closed state to filter the emboli, so that the normal embolic filtering capacity of the vascular interventional stent is not affected, and the vascular interventional stent is convenient to use. And the anchoring and fixing are carried out in the blood vessel through the tubular supporting structure, the anchoring capacity is strong, the anchoring effect is good, the vascular intervention stent can adapt to the condition of faster blood flow velocity, is more suitable for the intervention treatment of intracranial blood vessels, can ensure the stability of the vascular intervention stent fixation, and is safe and reliable to use. Moreover, the filtering structure is of an opening structure, is easier to deform when the vascular intervention stent is pressed and held, is convenient to press and hold and enters the conveying sheath tube, and solves the problem that the filtering structure is excessively plastic deformed and cannot rebound. It will be appreciated that when the filtering structure is subjected to only the forces exerted by the blood flow, including the forces exerted by the intercepted thrombus, the filtering structure remains closed as the blood flow or the forces exerted by the thrombus are significantly less than the external forces exerted by the interventional medical device, which is negligible for the filtering structure. Generally, the force of the intracranial blood is less than 0.05N, while the pushing force of the interventional medical device is greater than 1N. The term "external force" as used herein refers to forces other than normal blood flow or thrombotic forces, such as those exerted by interventional medical devices during delivery or use.

In more detail, the support structure is tubular, and the filter structure is a mesh structure and is connected to the support structure. The filter structure has a closed state and an open state for capturing a target (i.e., an embolic) entering the support structure when the filter structure is in the closed state. The filtering structure is configured to transition from the closed state to the open state upon application of an external force in an axial direction of the vascular access stent while allowing an external mechanism (e.g., other interventional medical devices) to pass through the filtering structure. The filter structure is further configured to transition from the open state to the closed state upon release of the external force.

Further, in the invention, the filtering structure comprises a plurality of filtering rods, at least part of the first ends of the filtering rods are connected with the supporting structure, and at least part of the second ends of the filtering rods are suspended; the second ends of the hanging arrangement are mutually close and overlap joint to realize the closing of the filtering structure, and when the filtering structure is subjected to the action of external force, for example, pushing the pushing force of other intervention medical instruments, the second ends of the hanging arrangement are mutually separated, so that the filtering structure is opened, other intervention medical instruments can pass through the filtering structure, but when the filtering structure is relieved of the action of external force of the other intervention medical instruments, the second ends of the hanging arrangement are mutually close and overlap joint together to seal the filtering structure again, and normal filtering is ensured. It should be understood that the aforementioned "overlap" refers to the case where at least a portion of the filter rods overlap each other by a certain length or, although not overlapping in length but abutting each other, are not fixedly connected but are optionally abutted together or abutted together at a predetermined angle (which may be achieved by a heat treatment or the like) and are relatively movable.

Further, the filter structure and the support structure are preferably integrally formed structures, such as integrally woven from woven filaments, or integrally cut from laser. In other cases, the filter structure and the support structure may be formed as separate structures, i.e. assembled together after being manufactured separately. Compared with split molding, the integrally molded vascular intervention stent has smaller size, does not need assembly, and can avoid the risk of assembly failure. Further, the support structure may be a self-expanding stent structure, such as a self-expanding braided stent or a self-expanding cut stent, or the support structure may also be a passive expanding stent structure, such as a balloon-expanding stent.

Furthermore, the material of the vascular intervention stent is a medical material with good biocompatibility, such as a medical polymer material or a metal material, and the materials of the supporting structure and the filtering structure can be the same or different. Still further, the material of the support structure and/or the filter structure of the present invention is nickel-titanium alloy, cobalt-chromium alloy or stainless steel. Preferably, the material of the support structure and/or the filter structure of the present invention is a biodegradable material, including but not limited to polylactic acid or magnesium alloy. If the vascular intervention stent is made of biodegradable materials, the vascular intervention stent can be used for avoiding risks caused by permanent implantation, such as thrombus, and also avoiding operation risks existing in the recovery stent, especially for intracranial operation, the operation difficulty and operation risks are large, and the degradable vascular intervention stent can avoid the problem, so that the operation safety is greatly improved, the injury to patients caused by the operation is also reduced, and the medical effect is improved.

Furthermore, the vascular intervention stent is mainly applied to intracranial blood vessels, realizes the purpose of filtering emboli in the intracranial blood vessels for a long time, replaces the anti-coagulation treatment for preventing AIS, avoids intracranial hemorrhage risks caused by the anti-coagulation treatment, and improves the embolism prevention effect.

Because intracranial blood vessels are thinner, filtered emboli are smaller, and the size of a filter screen mesh used in general peripheral blood vessels is larger, so that smaller emboli cannot be filtered. In the invention, the filtering structure comprises a plurality of filtering meshes, and the maximum width of the filtering meshes is not more than 0.2mm so as to effectively filter the tiny thrombus in the blood vessel. More preferably, the maximum width of the filter mesh is 0.15 mm-0.2 mm, in which case, the filter mesh can not only better filter smaller emboli in intracranial blood vessels, but also ensure that the filter mesh does not obstruct the passage of blood flow. It will be appreciated that the width of a filter mesh refers to the dimension of the filter mesh in the radial cross section of the filter structure, depending on the shape of the filter mesh, the maximum width being the distance between the two furthest points in the mesh. For example, when the filter mesh is circular or elliptical, the width is the aperture of the filter mesh, and the maximum width of the ellipse is the length of the major axis.

Further, in some embodiments, the entire length of the filter structure does not overlap the support structure in the axial direction of the support structure, i.e., the entire filter structure is disposed outside the support structure, in which case the filter structure is more easily compressed, the compressed size of the entire stent is small, facilitating smooth compression into the delivery sheath, and the diameter of the delivery sheath is small, facilitating pushing within a small intracranial vessel. However, in other embodiments, the entire length of the filter structure may also overlap the support structure at least partially in the axial direction of the support structure, i.e. at least part of the filter structure is arranged inside the support structure, in which case the entire length of the stent is shorter and the stent is subjected to less friction in the delivery system, which is advantageous for reducing the delivery resistance. Here, at least partial overlap of the filter structure with the support structure means that at least part of the filter structure extends from the end face of the support structure to the side wall of said support structure.

Further, the supporting structure is in a net pipe shape and comprises a plurality of supporting rods, the diameter of the supporting structure after expansion can be selected to be 3.0-6.0 mm, and the included angle between the supporting rods and the radial cross section of the supporting structure can be selected to be 10-45 degrees.

The vascular intervention stent proposed by the invention is further described below with reference to the accompanying drawings and several embodiments.

Example 1

Fig. 1a to 1c are a front view, an axial cross-sectional view and a top view, respectively, of a vascular access stent according to a first embodiment of the present invention.

As shown in fig. 1a to 1c, the vascular access stent 10 comprises a support structure 1 and a filtering structure 2. The support structure 1 is tubular and may be woven from braided filaments or cut by laser. The support structure 1 may be a self-expanding structure or may be passively inflated by an inflatable balloon. Further, the expanded diameter D of the support structure 1 is 3.0mm to 4.5mm, preferably 3.5mm, and can be applied to finer blood vessels, especially intracranial blood vessels.

The supporting structure 1 specifically includes a plurality of supporting rods 11, and the plurality of supporting rods 11 are distributed together in a certain manner to form a net-shaped supporting structure 1, but the shape of the net holes on the supporting structure 1 is not limited in the invention, and the net holes can be quadrangular net holes, pentagonal net holes, hexagonal net holes, elliptic net holes or the like, so as to provide sufficient supporting force in the radial direction. Further, in the expanded state of the vascular access stent 10, the included angle α between the support rod 11 and the radial cross section of the support structure 1 is preferably 10 ° to 45 °, so as to provide a sufficiently strong radial supporting force, so that the vascular access stent 10 is fixed more firmly. Still further, the included angle α is 30 ° to 35 ° when the diameter D of the support structure 1 after expansion is 3.0mm to 4.5mm, and preferably, the included angle α is 27 ° when the diameter D of the support structure 1 after expansion is 3.5mm.

The filtering structure 2 is a filtering net structure, which is disposed at one side of the supporting structure 1 and connected with the supporting structure 1, and the filtering structure 2 has a closed state and an open state, when the filtering structure 2 is in the closed state, the filtering structure is used for capturing emboli entering the supporting structure 1, and when the filtering structure 2 is subjected to an external force along the axial direction of the vascular intervention support 10, the filtering structure is converted into the open state by the closed state, and other intervention medical instruments are allowed to pass through the filtering structure 2, and when the filtering structure 2 is relieved of the external force, the filtering structure is converted into the closed state by the open state, and the emboli can be captured normally. Further, the filtering structure 2 is integrally woven or integrally cut with the supporting structure 1.

However, in practical applications, the entire length of the filtering structure 2 may at least partially overlap the supporting structure 1 in the axial direction of the supporting structure 1, or the entire length of the filtering structure 2 may not overlap the supporting structure 1 in the axial direction of the supporting structure 1. In this embodiment, as shown in fig. 1a and 1b, the whole length of the filtering structure 2 completely overlaps with the supporting structure 1 in the axial direction of the supporting structure 1, that is, the whole filtering structure 2 is not exposed outside the supporting structure 1 in the view angle shown in fig. 1a, so that the filtering structure 2 can be compressed in the supporting structure 1 during conveying, the whole length during conveying is reduced, the conveying resistance is reduced, and the axial length after the stent is released is shortened. Further, the shape of the filter structure 2 is not limited, and may be a planar structure or a three-dimensional structure. In this embodiment, the filtering structure 2 is disposed at one end (such as a distal end or a proximal end) of the supporting structure 1, so that a flat and spread radial filter screen is configured at one end of the supporting structure 1 to capture emboli, and the filtering structure 2 includes a plurality of filtering rods 21, where the filtering rods 21 are radially arranged in a plane. In this embodiment, the filtering structure 2 is disposed at the distal end of the supporting structure 1, so as to avoid the distal end of the vascular interventional stent from damaging the blood vessel. Of course, the filtering structure 2 is not limited to be disposed at the distal end of the supporting structure 1, but may be disposed at the proximal end of the supporting structure 1, and the exposed tip at the distal end of the supporting structure 1 is eliminated by optimizing the process or braiding back the structure, so as to avoid the distal end of the supporting structure 1 from damaging the blood vessel. Further, when the filter structure 2 is arranged at the proximal end of the support structure 1, the distal edge of the support structure 1 is configured in a wave-like structure; when the filter structure 2 is arranged at the distal end of the support structure 1, the proximal edge of the support structure 1 is configured in a wave-like structure.

The filter structure 2 includes a plurality of filter rods 21, and the present invention is not limited to a specific number of filter rods 21, as long as the formation of a filter screen can be ensured. As shown in fig. 1c, in this embodiment, the first ends of all the filtering rods 21 are arranged along the circumferential direction of the supporting structure 1, preferably uniformly arranged, so as to form a uniformly distributed filtering net, which has a good filtering effect. And every filter rod 21's first end with bearing structure 1 connects (in integrated into one piece, bearing structure 1's tip edge directly outwards extends constitutes filter rod 21), and every filter rod 21's second end unsettled setting, simultaneously filter rod 21's second end draws close and overlap joint each other, in this case, filter rod's one end is connected with bearing structure 1, and the other end is unsettled and draw close each other, makes filter structure 2 constitute plane radial filter screen to under the axial external force effect along the vascular intervention support, filter structure 2 can open completely, is convenient for other intervention medical instrument to pass through. In other embodiments, a portion of the second end of the filtering rod 21 may be connected to the support structure 1, so long as the filtering structure 2 may be partially opened for other interventional medical devices to pass through, and the filtering structure 2 helps to improve the radial supporting force of the vascular interventional stent, so that the vascular interventional stent is anchored more firmly in the blood vessel.

The filter structure 2 further comprises a plurality of filter meshes, wherein in the plane radial filter screen, a plurality of filter meshes are distributed along the circumferential direction of the support structure 1, and as shown in fig. 1c, the maximum width W of the filter meshes along the circumferential direction is not more than 0.2mm, and further, the maximum width W is 0.15-0.2 mm.

It should be noted that, the filtering structure 2 of this embodiment can be opened, and when a pushing force is sufficiently applied, the filtering structure 2 can be opened at its central position (a region close to the central axis of the stent) or can be opened at a region deviated from the central position, and the opened position is specifically set according to the overlap length of the filtering rod 21, but under the effect of normal blood flow impact force, the filtering structure of the present invention is insufficient to be opened to ensure normal filtering, for example, the filtering structure is structurally or materially ensured to have sufficient strength to avoid being opened by blood flow impact.

Further, as shown in fig. 1b, in this embodiment, among all the filter rods having the second end suspended, a projection length L of at least a portion of the filter rods 21 on a radial plane of the support structure 1 satisfies the following requirements:

D/2≤L≤D

If the projection length of each filter rod 21 is set according to the above formula, it is convenient to configure the filter structure 2 to be opened at its centered position, i.e. the overlapping position of the filter rods 21 is centered. However, in other embodiments, the overlapping position may be offset from the center, for example, where a portion of the filter rod has a projected length L that satisfies the above equation and another portion of the filter rod has a projected length L that is less than D/2, which may change the overlapping position (or overlap position) of the filter rod 21.

Further, in the present embodiment, the projection length L of each filter rod 21 satisfies the requirement of the above formula, and when the diameter D of the support structure 1 after expansion is 3.0mm to 4.5mm, the projection length L is 1.5mm to 4.5mm, preferably 3.0mm to 3.5mm. For example, when the support structure 1 has an expanded diameter D of 3.5mm, the projected length L is 3.0mm.

Example two

The structure of the vascular intervention stent provided in this embodiment is substantially the same as that of the first embodiment, and only the differences will be described below, and the same parts will not be described in detail.

Fig. 2a to 2c are a front view, an axial cross-sectional view and a top view, respectively, of a vascular access stent according to a second embodiment of the present invention.

As shown in fig. 2 a-2 c, the vascular access stent 20 comprises a support structure 3 and a filtering structure 4. The diameter D of the expanded support structure 3 can be selected to be 5.5-6.0 mm, and the expanded support structure can be applied to blood vessels with larger diameters. The support structure 3 comprises a plurality of support rods 31, and the included angle alpha between the support rods 31 and the radial cross section of the support structure 3 is preferably 10-15 degrees, so that the support with larger diameter is endowed with good radial support performance, and the vascular intervention support 20 is fixed more stably.

The filter structure 4 is a filter screen structure and comprises a number of filter rods 41. As shown in fig. 2c, the filter rods 41 are radially arranged, and further, as shown in fig. 2a and 2b, the filter rods 41 are spatially radially arranged at one end of the support structure 3, and the entire length of the filter structure 4 is not overlapped with the support structure 3 along the axial direction of the support structure 3, that is, the entire filter structure 4 is outside the support structure 3. Further, as shown in fig. 2a, the shape of the filtering structure 4 is dome-shaped in the expanded state of the vascular access stent 20, and in other embodiments, the filtering structure 4 may be conical (e.g., conical).

In addition, the projection length L of each filter rod 41 also satisfies the requirement of the formula described in the first embodiment, and when the diameter D of the support structure 3 after expansion is 5.5mm to 6.0mm, the projection length L of each filter rod 41 is 2.8mm to 6.0mm, preferably 4.0mm to 4.5mm. For example, when the support structure 3 has an expanded diameter D of 6.0mm, the projected length L is 4.5mm. Regarding other aspects, the structure of the vascular access stent 20 of the present embodiment is substantially the same as that of the first embodiment, and will not be described in detail. In addition, by arranging the filtering structure 4 outside the supporting structure 3, the advantage is that the supporting structure 3 can be compressed smoothly, and the compression size of the vascular intervention stent is reduced, so that the whole device can be loaded into the delivery sheath smoothly.

Example III

Fig. 3a to 3c are a front view, an axial cross-sectional view and a top view, respectively, of a vascular access stent according to a third embodiment of the present invention.

As shown in fig. 3 a-3 c, the vascular access stent 30 comprises a support structure 5 and a filter structure 6. The diameter D of the expanded support structure 5 is optionally 4.5mm to 5.5mm, and can be applied to a blood vessel with a medium diameter. The support structure 5 comprises a plurality of support rods 51, and the included angle alpha between the support rods 51 and the radial cross section of the support structure 5 is preferably 20-25 degrees, so that the support with smaller diameter has good radial support performance and compliance to tortuous vessels, and the vascular intervention support 30 is fixed more firmly.

The filter structure 6 is a filter screen structure and comprises a number of filter rods 61. As shown in fig. 3c, in the expanded state of the vascular access stent 30, the filtering rods 61 are arranged in a planar checkerboard shape and are arranged at one end of the supporting structure 5, and the whole length of the filtering structure 6 overlaps with the supporting structure 5 along the axial direction of the supporting structure 5, i.e. a flat spreading checkerboard-shaped filter screen is configured at the proximal end or the distal end of the supporting structure 5 to capture emboli.

More specifically, the first portion of the filter rods 61 extends along a first direction, the second portion of the filter rods 61 extends along a second direction, and the first direction and the second direction are disposed at a predetermined angle, so that the filter rods 61 are arranged in a planar checkerboard shape. The first direction may be perpendicular or non-perpendicular to the second direction. Further, the third partial filter rod 61 extends in a third direction, and the first direction, the second direction and the third direction are respectively at an angle of 120 °. In other embodiments, the filtering structure 6 further includes filtering rods 61 extending in other directions, such as a fourth portion of filtering rods 61 extending in a fourth direction, where the first direction, the second direction, the third direction, and the fourth direction are disposed at predetermined angles. Further, among all the filter rods 61 extending along the first direction, two ends of a plurality of shorter filter rods 61 are connected with the supporting structure 5, and a first end of a plurality of longer filter rods 61 is connected with the supporting structure 5, and a second end is suspended; meanwhile, among all the filter rods 61 extending along the second direction, two ends of the filter rods 61 with shorter lengths are connected with the supporting structure 5, first ends of the filter rods 61 with longer lengths are connected with the supporting structure 5, and second ends of the filter rods 61 extending along the first direction are suspended and mutually close to and overlap with second ends of the suspended filter rods. Thus, both ends of a part of the filter rods of the filter structure 6 of the present embodiment are connected to the support structure 5, for example, both ends of the outermost short filter rod 61 in each direction are connected to the support structure 5, while the first ends of the middle ones of the longer filter rods are connected to the support structure 5, and the second ends thereof are not connected to the support structure 5 and are suspended, of course, in each direction, the positions of the free ends of the adjacent two filter rods 61 may be opposite or adjacent, i.e., the adjacent two filter rods 61 may be disposed opposite or in the same direction, so long as all the free ends can be brought close to each other and overlap together, so as to facilitate the opening of the filter structure 6 in the central position.

The filter structure 6 further comprises a number of filter meshes. In this embodiment, as shown in fig. 3c, in the planar checkerboard-shaped filter screen, a plurality of the filter cells are distributed in a matrix along the first direction and the second direction, and the maximum width W (i.e., the length of the longest side) of the filter cells is not more than 0.2mm, more preferably, the maximum width W is 0.15mm to 0.2mm. Here, the long side is a longer side with respect to the short side. Moreover, the width W of the checkerboard meshes is more uniform than that of the radial meshes, and the filtering effect is better. In other embodiments, the filter mesh may also be square, diamond, etc. shaped, such that the maximum dimension of the filter mesh is no more than 0.2mm, and more preferably the maximum dimension is between 0.15mm and 0.2mm.

Furthermore, the projected length of the filter rods 61 having free ends also satisfies the requirement of the formula described in embodiment one, and when the diameter D of the support structure 5 after expansion is 4.5mm to 5.5mm, the projected length L of each filter rod 61 is 2.3mm to 5.5mm, preferably 3.5mm to 4.0mm. For example, the expanded diameter D of the support structure 5 is 5.0mm and the projected length L is 3.5mm. Regarding other aspects, the structure of the vascular access stent 30 of the present embodiment is substantially the same as that of the first embodiment, and will not be described in detail.

The preferred embodiments of the present invention are described above, but not limited to the scope of the embodiments disclosed above, for example, the present invention is not limited to the shape of the filtering structure, including but not limited to the checkerboard shape and the radial shape, and also can be honeycomb shape, etc., the present invention is not limited to the expanded diameter of the supporting structure, which is especially suitable for small intracranial vessels, and the present invention is not limited to the material of the whole vascular intervention stent, including but not limited to nickel-titanium alloy, chromium-cobalt alloy, stainless steel, polylactic acid and magnesium alloy, and the materials of the supporting structure and the filtering structure can be the same or different. In addition, when the external force applied to the filtering structure is released, the filtering structure is converted from the open state to the closed state under the action of self resilience force.

In conclusion, the vascular intervention stent achieves the aim of filtering emboli in blood vessels, particularly intracranial blood vessels, for a long time through the supporting structure and the filtering structure, can replace anticoagulation treatment to prevent AIS, and avoids intracranial hemorrhage risks caused by anticoagulation treatment. Meanwhile, the filtering structure can be opened when the external force acts on the filtering structure, so that other interventional medical instruments such as a catheter, other stents and the like are allowed to pass through the vascular interventional stent of the invention for the second time, the filtered thrombus is conveniently treated by the suction catheter, the thrombus taking device and the like, the interventional therapy is also conveniently carried out on other parts of the blood vessel, the disease treatment effect is further improved, meanwhile, a doctor is allowed to carry out more complex operation, and the operation effect is improved. However, after external force is removed, the filtering structure can automatically recover to a closed state to filter the emboli, so that the normal embolic filtering capability of the vascular interventional stent is not affected, and the use is convenient. And anchor fixedly in the blood vessel through being tubular bearing structure, anchor strong ability, anchoring effect is good, makes this blood vessel intervene the support and need not to set up extra anchor again and just can adapt to the circumstances that blood flow velocity is faster, can ensure the vascular intervention support fixed steadiness, uses safe and reliable. Moreover, the filtering structure is an opening structure, is easier to deform when being pressed and held, is convenient to enter the conveying sheath after being pressed and held, and avoids the problem that the filtering structure cannot rebound due to overlarge plastic deformation.

The above description is only illustrative of the preferred embodiments of the present invention and is not intended to limit the scope of the present invention, and any alterations and modifications made by those skilled in the art based on the above disclosure shall fall within the scope of the appended claims.

Claims

1. A vascular access stent for filtering emboli within a blood vessel, comprising a support structure and a filtering structure; the support structure is tubular and is used for anchoring and fixing in a blood vessel; the filtering structure is a net structure, is arranged at one end of the supporting structure and is connected with the supporting structure; the filter structure has a closed state and an open state;

the filtering structure is configured to transition from the closed state to the open state upon application of an external force in an axial direction of the vascular access stent to allow an external mechanism to pass through the vascular access stent; the filtering structure is further configured to transition from the open state to the closed state upon release of the external force to capture emboli;

the filter structure comprises a plurality of filter rods, at least part of the first ends of the filter rods are connected with the support structure, and at least part of the second ends of the filter rods are suspended;

2. The vascular access stent of claim 1, wherein the first ends of the filter rods are arranged circumferentially of the support structure.

3. The vascular access stent of claim 2, wherein a first end of each of the filter rods is connected to the support structure, a second end of each of the filter rods is suspended, and the second ends of all of the filter rods are brought together and overlap.

4. The vascular access stent of claim 1, wherein the filter rods are arranged radially in a plane, radially in a solid, or in a checkerboard pattern.

5. The vascular access stent of claim 4, wherein the filter structure is dome-shaped or cone-shaped when the filter rods are spatially radially arranged.

6. The vascular access stent of claim 4, wherein a first portion of the filter rods extend in a first direction and a second portion of the filter rods extend in a second direction, and wherein the first direction is disposed at a predetermined angle to the second direction such that the filter rods are in a planar checkerboard arrangement.

7. The vascular access stent of claim 6, wherein of all the filter rods extending in the first direction, a plurality of shorter filter rods are connected at both ends to the support structure, and a plurality of longer filter rods are suspended at the first ends to the support structure;

8. The vascular access stent of claim 1, wherein the projected length of at least a portion of all filter rods suspended from the second end on a radial plane of the support structure meets the following requirements:

D/2≤L≤D

9. The vascular access stent of any one of claims 1-8, wherein the filtering structure is disposed at one end of the support structure;

10. The vascular access stent of claim 1, wherein the filtering structure is an integral structure with the support structure.

11. The vascular access stent of claim 10, wherein the filtering structure is integrally woven with the support structure from braided filaments or the filtering structure is integrally cut with the support structure from a laser.

12. The vascular intervention stent of claim 1, wherein the support structure is in a mesh tube shape and comprises a plurality of support rods, the diameter of the support structure after expansion is 3.0 mm-6.0 mm, and the included angle between the support rods and the radial cross section of the support structure is 10-45 degrees.

13. The vascular intervention stent of claim 12, wherein the expanded diameter of the support structure is 3.0 mm-4.5 mm, and the included angle between the support rod and the radial cross section of the support structure is 30-35 degrees; or the diameter of the support structure after expansion is 4.5 mm-5.5 mm, and the included angle between the support rod and the radial cross section of the support structure is 20-25 degrees; or the diameter of the support structure after expansion is 5.5 mm-6.0 mm, and the included angle between the support rod and the radial cross section of the support structure is 10-15 degrees.

14. The vascular access stent of claim 1, wherein the material of the support structure and/or the filter structure is nickel-titanium alloy, cobalt-chromium alloy, stainless steel, polylactic acid or magnesium alloy.

15. The vascular access stent of claim 1, wherein the filtering structure comprises a plurality of filtering mesh openings, the maximum width of the filtering mesh openings not exceeding 0.2mm.

16. The vascular access stent of claim 15, wherein a plurality of the filter mesh openings are distributed along a circumferential direction of the support structure, and wherein a maximum width of the filter mesh openings along the circumferential direction is no more than 0.2mm.

17. The vascular access stent of claim 15, wherein a plurality of the filter cells are distributed along a first direction and a second direction, and wherein a maximum width of the filter cells is no more than 0.2mm, the first direction being disposed at a predetermined angle to the second direction.

18. The vascular access stent of claim 15, wherein the maximum width of the filter mesh is 0.15 mm-0.2 mm.

19. The vascular access stent of claim 1, wherein the vascular access stent is an intracranial vascular access stent.

20. The vascular access stent of claim 1, wherein the filtering structure transitions from the open state to the closed state under the force of self-resilience when the external force applied to the filtering structure is released.