CN113017945A

CN113017945A - Blood vessel intervention stent

Info

Publication number: CN113017945A
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: 2021-06-25
Anticipated expiration: 2039-12-25
Also published as: CN113017945B

Abstract

The invention relates to an intravascular interventional stent, which is mainly applied to filtering of intracranial blood vessels, can realize the purpose 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 treatment effect of diseases. The vascular intervention stent comprises a supporting structure and a filtering structure, wherein the supporting structure is tubular, the filtering structure is a net structure and is connected with the supporting structure, the filtering structure has a closed state and an open state, when the filtering structure is configured to be acted by 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 also configured to be released from the external force, the filtering structure is converted into the closed state from the open state.

Description

Blood vessel intervention stent

Technical Field

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

Background

Emboli from the heart and aorta block the arteries supplying blood to the brain, which can cause Transient Ischemic Attacks (TIA) and strokes. In China, emboli of about half of patients with Acute Ischemic Stroke (AIS) originate from the heart. Emboli can be caused by atrial fibrillation, left ventricular thrombosis, dilated cardiomyopathy, rheumatic valvular disease, artificial heart valves, heart failure, myocardial infarction recently appeared in high-risk patients and the like. According to the National Institute of Health (NIH) stroke database, about 60% of all strokes are caused by embolism, and 14% -30% of ischemic strokes are caused by cardiogenic embolism. Even if the chance escapes the first AIS stroke attack, it is difficult to ensure that the next blockage of the cerebral supply artery does not occur.

Atrial fibrillation patients with a history of stroke or TIA that are the source of cardiac embolism are treated with lifelong anticoagulation at present. The most important risk of anticoagulant therapy is bleeding complications, especially intracranial bleeding, which, once bleeding, can lead to death or disability. However, the bleeding risk associated with anticoagulation can be circumvented by interventional therapy. In interventional therapy, a distal protection umbrella is used to filter broken plaque or thrombus only when a thrombus removal stent or a carotid artery stent is applied, and the distal protection umbrella is removed after the operation is finished, so that the capability of filtering embolus for a long time is not provided. Other intracranial vascular stents are rather incapable of filtering emboli. Moreover, the existing intravascular filtering device has the following problems and is not suitable for intracranial blood vessels:

1. the mesh of the filter screen is large, the filtering capacity is insufficient, the anchoring force is low, and the filter screen cannot adapt to intracranial blood vessels with faster blood flow speed and smaller embolus;

2. the intracranial vascular access is complicated, the difficulty of the interventional operation is high, the operation instrument needs to be passed through for the second time sometimes, but the totally closed filtering device can not meet the requirement;

3. the filtering device and the anchoring device are mutually independent and need to be assembled in a certain connection mode, the intracranial interventional device is extremely small in size and high in assembly difficulty, the risk of assembly failure is introduced, and the whole device is large in size;

4. regular recovery is needed, 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 interventional stent, which can avoid anticoagulant drug therapy and intracranial hemorrhage risk caused by the anticoagulant drug therapy, and also allows other interventional medical devices to conveniently perform other interventional therapies through the part implanted with the stent, thereby improving the disease treatment effect.

The invention provides a vascular intervention stent, which comprises a support structure and a filter structure, wherein the support structure is tubular, and the filter structure is a net structure and is connected with the support structure; the filter structure has a closed state and an open state;

the filtering structure is configured to be changed from the closed state to the open state when being subjected to an external force along the 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 includes a plurality of filtering rods, at least a portion of the filtering rods are connected to the supporting structure at first ends thereof, and at least a portion of the filtering rods are suspended at second ends thereof;

the second ends of the suspended devices are mutually close and lapped to realize the closing of the filtering structure; and when the filtering structure is acted by the external force, the second ends of the suspended arrangement are mutually separated so as to open the filtering structure, and when the filtering structure releases the external force, the second ends of the suspended arrangement are mutually closed and lapped.

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

Optionally, each first end of the filter rod is connected with the support structure, each second end of the filter rod is arranged in a suspended mode, and the second ends of the filter rods are mutually close and overlapped.

Optionally, the filter rods are arranged in a planar radial manner, a three-dimensional radial manner or a planar checkerboard manner.

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

Optionally, the first part of the filter rods extend along a first direction, the second part of the filter rods extend 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 planar chessboard shape.

Optionally, in all the filter rods extending in the first direction, both ends of a plurality of shorter filter rods are connected to the support structure, first ends of a plurality of longer filter rods are connected to the support structure, and second ends of the plurality of longer filter rods are arranged in a suspended manner;

follow in all filter rods that the second direction extends, a plurality of shorter filter rod's both ends all with bearing structure connects, and is a plurality of longer filter rod's first end with bearing structure connects, the unsettled setting of second end and follow first direction extends filter rod's the second end of unsettled setting is drawn close each other and the overlap joint.

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

D/2≤L≤D

wherein: l is the projected length and D is the expanded diameter of the support structure.

Optionally, the filter 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 filter structure and the support structure are an integrally formed structure.

Optionally, the filter structure and the support structure are integrally woven by weaving yarns, or the filter structure and the support structure are integrally cut by laser.

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

Optionally, the expanded diameter of the support structure is 3.0mm to 4.5mm, and an included angle between the support rod and the radial cross section of the support structure is 30 degrees to 35 degrees; or the diameter of the expanded supporting structure is 4.5 mm-5.5 mm, and the included angle between the supporting rod and the radial cross section of the supporting structure is 20-25 degrees; or the diameter of the expanded supporting structure is 5.5 mm-6.0 mm, and the included angle between the supporting rod and the radial cross section of the supporting 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 plurality of filter mesh openings, the maximum width of the filter mesh openings not exceeding 0.2 mm.

Optionally, a plurality of the filter meshes are distributed along the circumferential direction of the support structure, and the maximum width of the filter meshes along the circumferential direction is not more than 0.2 mm.

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

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

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

Optionally, 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 blood vessel interventional stent realizes the purpose of filtering embolus 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 risk caused by anticoagulation treatment. Meanwhile, the filtering structure can be opened when being acted by external force, so that other interventional medical instruments, such as catheters, other stents and the like, are allowed to pass through the blood vessel interventional stent of the invention for a second time, the filtered thrombus is conveniently treated through the suction catheter, the thrombus taking device and the like in the follow-up process, the interventional treatment is also conveniently carried out at other parts of the blood vessel, the disease treatment effect is further improved, and meanwhile, doctors are allowed to carry out more complicated operation, and the operation effect is improved. However, after the external force is removed, the filtering structure can automatically return to the closed state to filter emboli, the normal emboli filtering capability of the blood vessel intervention stent is not influenced, and the use is convenient. And through being pipy bearing structure anchor fixedly in the blood vessel, anchoring ability reinforce, anchoring effect is good, makes this blood vessel intervene the support and need not to set up the faster condition of extra anchoring device just can adapt to the blood flow velocity again, can ensure that the blood vessel intervenes the fixed steadiness of support, and is safe in utilization reliable again. Moreover, the filtering structure is of an open 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.

Above-mentioned blood vessel intervenes support is integrated into one piece structure, if integrative cutting or weave and form, helps controlling the whole size that blood vessel intervenes the support, is convenient for carry in tiny blood vessel, has also avoided the components of a whole that can function independently shaping to connect the risk of losing efficacy when the assembly simultaneously, has improved the reliability and the security of product.

The filtering structure of the blood vessel intervention stent uses filtering meshes with the maximum width not more than 0.2mm, is favorable for capturing finer emboli, and has good filtering effect.

The blood vessel intervention stent can be made of biodegradable materials, and secondary operation is avoided, so that thrombus risk caused by permanent implantation is avoided, operation risk caused by stent recovery is also avoided, and the safety of the operation is improved.

Drawings

Fig. 1a is a front view of a vascular access stent provided by a first embodiment of the present invention;

FIG. 1b is an axial cross-sectional view of a stent for vascular intervention according to a first embodiment of the present invention;

FIG. 1c is a top view of a stent for vascular intervention according to a first embodiment of the present invention;

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

FIG. 2b is an axial cross-sectional view of a stent for vascular intervention according to a second embodiment of the present invention;

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

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

FIG. 3b is an axial cross-sectional view of a stent for vascular intervention according to a third embodiment of the present invention;

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

In the figure:

10. 20, 30-vessel intervention stent;

1. 3, 5-support structure;

11. 31, 51-support bars;

2. 4, 6-filtration structure;

21. 41, 61-filter rods;

l-the projected length of the filter rod;

w-the maximum width of the filter mesh;

the angle between the alpha-support bar and the radial cross section of the support structure.

The same or similar elements are designated by different reference numerals in the drawings.

Detailed Description

To further clarify the objects, advantages and features of the present invention, a more particular description of the invention will be rendered by reference to the appended drawings. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present 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 a sense that it includes two or more, unless the content clearly dictates otherwise. The term "plurality" is generally employed in a sense including an indefinite amount unless the content clearly dictates otherwise. The term "proximal" generally refers to the end that is proximal to the operation of a medical device, and "distal" refers to the end that is distal to the operation of a medical device, unless the context clearly dictates 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 thin pipe diameter, such as intracranial blood vessels. The vascular access stent comprises a support structure and a filtering structure. Particularly, by arranging a structure design of the filter structure which can be opened at one end of the tubular support structure, when the filter structure is implanted into a blood vessel but is not opened, emboli can be filtered normally through the filter structure, and when the filter structure is opened under the action of external force exerted by other interventional medical devices (such as catheters, guide wires and the like), other interventional medical devices are allowed to pass through the blood vessel part implanted into the blood vessel interventional stent, so that interventional treatment can be conveniently carried out at other parts of the blood vessel or interventional treatment of multiple devices can be carried out at the same part, and by doing so, the disease treatment effect can be improved, and meanwhile, doctors are allowed to carry out more complicated operation, and the operation efficiency is improved. However, after the external force of other interventional medical instruments is removed, the filtering structure can be restored to the closed state to filter emboli, the normal emboli filtering capability of the blood vessel interventional stent is not influenced, and the use is convenient. And through being the fixed of tubulose bearing structure anchor in the blood vessel, the anchoring ability reinforce, anchoring effect is good, makes this blood vessel intervene the support and can adapt to the condition that the blood flow velocity of flow is faster, more is adapted to intracranial vascular intervention treatment, can ensure the fixed steadiness of blood vessel intervention support, and is safe in utilization reliable again. Moreover, the filtering structure is an open structure, so that the blood vessel interventional stent is easier to deform when being pressed and held, and is convenient to enter the conveying sheath after being pressed and held, and the problem that the filtering structure cannot rebound due to overlarge plastic deformation is avoided. It will be appreciated that when the filter structure is subjected to only the forces exerted by the blood flow, including the forces exerted by the intercepted thrombus, the filter structure remains in a closed state at this time because the forces exerted by the blood flow or thrombus are significantly less than the external forces exerted by the interventional medical device and are negligible for the filter structure. Generally, the impulse of 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 a force other than that of normal blood flow or thrombus, such as that exerted by an interventional medical device during delivery or use.

In more detail, the support structure is tubular and the filtering structure is a net structure and is connected with the support structure. The filter structure has a closed state and an open state for capturing a target (i.e., embolus) entering the support structure when the filter structure is in the closed state. The filtering structure is configured to be transformed from the closed state to the open state when subjected to an external force along the axial direction of the vascular access stent, and an external mechanism (such as other interventional medical devices) is allowed 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.

Furthermore, 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 arranged in a suspended manner; the second end of unsettled setting is drawn close and the overlap joint each other to realize filtration's closure, and works as filtration receives during exogenic action, for example, other medical instrument's of interveneeing of propelling movement power, the second end of unsettled setting separates each other, and makes filtration opens to make other intervene medical instrument can pass through filtration, but work as when filtration is relieved other medical instrument's of interveneeing exogenic action, the second end of unsettled setting is drawn close each other again and the overlap joint is in the same place and seals once more filtration ensures can also normally filter. It should be understood that the term "overlap" refers to a condition in which at least a portion of the filter rods overlap each other by a certain length or abut each other without overlapping each other in length, but the "overlap" is not a fixed connection but abuts against each other randomly or at a predetermined angle (which may be achieved by a heat treatment or the like) and is capable of relative movement.

Further, the filter structure and the support structure are preferably integrally formed structures, such as integrally woven from woven filaments, or integrally cut by laser. In other cases, the filtering structure and the supporting structure may be formed as separate bodies, i.e. manufactured separately and then assembled together. Compared with split molding, the integrally molded blood vessel intervention stent has smaller size, does not need to be assembled, 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-expandable stent.

Furthermore, the material of the vessel intervention stent is a medical material with good biocompatibility, such as a medical polymer material or a metal material, and the material of the support structure and the material of the filter structure can be the same or different. Further, the material of the support structure and/or the filter structure of the present invention is nitinol, 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 blood vessel intervention stent is made of biodegradable materials, the blood vessel intervention stent can be used for avoiding risks caused by permanent implantation, such as thrombus, and also can avoid operation risks caused by stent recovery, particularly for intracranial operations, the operation difficulty and the operation risks are very large, and the degradable blood vessel intervention stent can avoid the problem, so that the operation safety is greatly improved, the harm of the operation to patients is reduced, and the medical effect is improved.

Furthermore, the blood vessel interventional stent is mainly applied to intracranial blood vessels, realizes the purpose of filtering embolus in the intracranial blood vessels for a long time, replaces anticoagulation treatment to prevent AIS, avoids intracranial hemorrhage risk caused by anticoagulation treatment, and improves the effect of embolism prevention.

Because intracranial vessels are thinner and smaller emboli are filtered, while the mesh size of the filter screens used in peripheral vessels is larger and smaller emboli cannot be filtered, the mesh size in the filtering structure of the present invention is designed to be smaller and smaller so as to filter smaller emboli. 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 that the filtering structure has the function of effectively filtering fine thrombus in blood vessels. More preferably, the maximum width of the filter mesh is 0.15 mm-0.2 mm, in this case, it can not only filter the smaller emboli in the intracranial blood vessel well, but also ensure that the filter mesh does not obstruct the blood flow. It will be understood that, depending on the shape of the filtering mesh, the width of the filtering mesh refers to the dimension of the filtering mesh in a radial cross section of the filtering structure, the maximum width then 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 pore size 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 filtering structure does not overlap the support structure in the axial direction of the support structure, i.e., the entire filtering structure is disposed outside the support structure, in which case the filtering structure is more easily compressed, the compressed size of the entire stent is small, facilitating smooth compression into the delivery sheath, and the delivery sheath has a small diameter, facilitating advancement in small intracranial vessels. However, in other embodiments, the entire length of the filter structure may at least partially overlap the support structure in the axial direction of the support structure, i.e. at least part of the filter structure is disposed inside the support structure, in which case the length of the entire stent is shorter and the friction force exerted on the stent in the delivery system is smaller, which is beneficial to reduce the delivery resistance. Here, that the filter structure at least partly overlaps the support structure means that at least part of the filter structure extends from an end face of the support structure onto a side wall of said support structure.

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

The present invention provides a stent for vascular intervention, which is further described below with reference to the accompanying drawings and several embodiments.

Example one

Fig. 1a to 1c are a front view, an axial sectional view and a plan view of a stent for vascular intervention according to a first embodiment of the present invention.

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

The support structure 1 specifically comprises a plurality of support rods 11, and the plurality of support rods 11 are distributed in a certain manner to form the mesh-shaped support structure 1, but the shape of the meshes on the support structure 1 is not limited in the invention, and the meshes can be quadrilateral meshes, pentagonal meshes, hexagonal meshes or elliptical meshes, and the like, and are used for providing sufficient support force in the radial direction. Further, in the expanded state of the blood vessel intervention 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 ° to provide a strong radial supporting force, so that the blood vessel intervention stent 10 is more stably fixed. Further, when the expanded diameter D of the support structure 1 is 3.0mm to 4.5mm, the included angle α is 30 ° to 35 °, and preferably, when the expanded diameter D of the support structure 1 is 3.5mm, the included angle α is 27 °.

The filtering structure 2 is a filtering net structure, is arranged on one side of the supporting structure 1 and is connected with the supporting structure 1, and the filtering structure 2 has a closed state and an open state, and 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 the action of external force along the axial direction of the blood vessel interventional stent 10, the filtering structure is changed into the open state from the closed state, other interventional medical instruments are allowed to pass through the filtering structure 2, and then when the external force is relieved from the filtering structure 2, the filtering structure 2 is changed into the closed state from the open state and can normally capture the emboli. Further, the filtering structure 2 and the supporting structure 1 are integrally woven or integrally cut.

However, in practical applications, the entire length of the filter structure 2 may at least partially overlap the support structure 1 in the axial direction of the support structure 1, or the entire length of the filter structure 2 may not overlap the support structure 1 in the axial direction of the support structure 1. In the present embodiment, as shown in fig. 1a and 1b, the entire length of the filter structure 2 completely overlaps the support structure 1 in the axial direction of the support structure 1, that is, the entire filter structure 2 is not exposed outside the support structure 1 in the view shown in fig. 1a, and thus the filter structure 2 can be compressed in the support structure 1 during transportation, the overall length during transportation is reduced, which helps to reduce the transportation resistance and shorten the axial length after stent release. 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 (e.g. the distal end or the proximal end) of the supporting structure 1, so that a flat 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, and the filtering rods 21 are arranged in a plane radial manner. In this embodiment, the filtering structure 2 is disposed at the distal end of the supporting structure 1 to avoid the distal end of the stent from damaging the blood vessel. Of course, the filtering structure 2 is not limited to be arranged at the distal end of the support structure 1, but may be arranged at the proximal end of the support structure 1, and the exposed tip at the distal end of the support structure 1 is eliminated by process optimization or by a back-woven structure, thereby avoiding the distal end of the support 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 as a wave-shaped 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 as a wave-like structure.

The filtering structure 2 comprises a plurality of filtering rods 21, and the specific number of the filtering rods 21 is not limited in the invention as long as the formation of a filter screen is ensured. As shown in fig. 1c, in this embodiment, the first ends of all the filter rods 21 are arranged along the circumferential direction of the supporting structure 1, preferably uniformly arranged, so as to form a uniformly distributed filter screen, and the filtering effect is good. And every filter pole 21 first end with bearing structure 1 is connected (in integrated into one piece, bearing structure 1's tip edge is direct outwards to extend constitutes filter pole 21), and every filter pole 21's second end unsettled setting, simultaneously filter pole 21's second end is drawn close each other and the overlap joint, and under this condition, filter pole's one end and bearing structure 1 are connected, and the other end is unsettled and is drawn close each other, makes filter structure 2 construct the radial filter screen in plane to under the axial exogenic action of interveneeing the support along the blood vessel, filter structure 2 can be opened completely, is convenient for other intervene medical instrument and passes through. In other embodiments, part of the second end of the filter rod 21 may also be connected to the support structure 1, as long as the filter structure 2 can be partially opened for other interventional medical devices to pass through, and the filter structure 2 helps to improve the radial support force of the vascular interventional stent, so that the anchoring of the vascular interventional stent in the blood vessel is more stable.

Filtration 2 still includes a plurality of filter meshes, and in plane radial filter screen, a plurality of filter meshes are followed support structure 1's circumference distributes, and as shown in fig. 1c, filter meshes along the maximum width W of circumference no longer than 0.2mm, and further, maximum width W is 0.15 ~ 0.2 mm.

It should be noted that the filter structure 2 of the present embodiment can be opened, and when a sufficiently large pushing force is applied, the filter structure 2 can be opened at its central position (the area close to the central axis of the stent) or at an area deviated from the central position, specifically, the opened position is set according to the overlapping length of the filter rods 21, but under the impact of normal blood flow, the filter structure of the present invention is not sufficiently opened to ensure normal filtration, for example, the filter structure is structurally or materially ensured to have sufficient strength to avoid being opened by the impact of blood flow.

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

D/2≤L≤D

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

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

Example two

The structure of the stent for vascular intervention provided in this embodiment is substantially the same as that of the first embodiment, and only different points will be described below, and the details of the same parts will not be described again.

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

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

The filtering structure 4 is a sieve structure and comprises a plurality of filtering 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 radially arranged in a three-dimensional manner and are arranged at one end of the support structure 3, and the entire length of the filter structure 4 does not overlap the support structure 3 in the axial direction of the support structure 3, i.e., the entire filter structure 4 is outside the support structure 3. Further, as shown in fig. 2a, in the expanded state of the vascular access stent 20, the shape of the filter structure 4 is a dome shape, and in other embodiments, the filter structure 4 may also be a cone shape (e.g., a cone).

Furthermore, the length L of each filter rod 41 also satisfies the requirements of the formula described in the first embodiment, and when the expanded diameter D of the support structure 3 is 5.5mm to 6.0mm, the length L of each filter rod 41 is 2.8mm to 6.0mm, preferably 4.0mm to 4.5 mm. For example, when the expanded diameter D of the support structure 3 is 6.0mm, the projected length L is 4.5 mm. In other respects, the structure of the 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 advantages are that the supporting structure 3 can be smoothly compressed, the compression size of the blood vessel interventional stent is reduced, and the whole device can be smoothly loaded into a conveying sheath.

EXAMPLE III

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

As shown in fig. 3a to 3c, the vascular access stent 30 includes a support structure 5 and a filter structure 6. The expanded diameter D of the support structure 5 can be 4.5 mm-5.5 mm, and can be applied to blood vessels with medium diameters. The supporting structure 5 comprises a plurality of supporting rods 51, and the included angle α between the supporting rods 51 and the radial cross section of the supporting structure 5 is preferably 20-25 °, so as to endow the stent with smaller diameter with good radial supporting performance and compliance to tortuous vessels, and ensure that the vascular access stent 30 is fixed more stably.

The filtering structure 6 is a filtering net structure and comprises a plurality of filtering rods 61. In the expanded state of the stent 30, as shown in fig. 3c, the filter rods 61 are arranged in a planar checkerboard pattern and are disposed at one end of the support structure 5, and the entire length of the filter structure 6 overlaps the support structure 5 along the axial direction of the support structure 5, i.e. a flat checkerboard-shaped filter screen is constructed at the proximal or distal end of the support structure 5 to capture emboli.

More specifically, a first portion of the filter rods 61 extends along a first direction, a second portion of the filter rods 61 extends along a second direction, and the first direction and the second direction are arranged at a predetermined angle, so that the filter rods 61 are arranged in a planar checkerboard shape. The first direction may or may not be 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 formed at an angle of 120 °. In other embodiments, the filter structure 6 further comprises filter rods 61 extending in other directions, for example, a fourth filter rod 61 extending in a fourth direction, and the first direction, the second direction, the third direction and the fourth direction are respectively arranged at predetermined angles therebetween. Furthermore, in all the filter rods 61 extending along the first direction, two ends of a plurality of shorter filter rods 61 are connected with the support structure 5, first ends of a plurality of longer filter rods 61 are connected with the support structure 5, and second ends of the plurality of longer filter rods 61 are arranged in a suspended manner; simultaneously along in all filter rods 61 that the second direction extends, a plurality of shorter filter rods 61's both ends all with bearing structure 5 connects, and is a plurality of longer filter rods 61's first end with bearing structure 5 connects, the unsettled setting of second end and edge filter rods 61 that the first direction extends the second end of unsettled setting is drawn close each other and the overlap joint. Therefore, 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 short filter rod 61 at the outermost side in each direction are connected to the support structure 5, while the first ends of the middle filter rods with a plurality of longer filter rods are connected to the support structure 5, and the second ends are not connected to the support structure 5 and suspended.

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

Furthermore, the projected length of the filter rods 61 with free ends also meets the requirements of the formula described in the first embodiment, and when the expanded diameter D of the support structure 5 is between 4.5mm and 5.5mm, the projected length L of each filter rod 61 is between 2.3mm and 5.5mm, preferably between 3.5mm and 4.0 mm. For example, the expanded diameter D of the support structure 5 is 5.0mm and the projected length L is 3.5 mm. In other respects, the structure of the 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 disclosure of the above embodiments, for example, the present invention does not limit the shape of the filtering structure, including but not limited to the chessboard shape and radial shape, and can be honeycomb shape, the present invention does not limit the expanded diameter of the supporting structure, which is especially suitable for small intracranial vessels, and the present invention does not limit the material of the whole vascular access stent, including but not limited to nitinol, inconel, 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 filter structure is released, the filter structure is changed from the open state to the closed state by the self-resilience force.

In conclusion, the blood vessel interventional stent realizes the purpose of filtering embolus 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 risk caused by anticoagulation treatment. Meanwhile, the filtering structure can be opened when being acted by external force, so that other interventional medical instruments, such as catheters, other stents and the like, are allowed to pass through the blood vessel interventional stent of the invention for a second time, the filtered thrombus is conveniently treated through the suction catheter, the thrombus taking device and the like in the follow-up process, the interventional treatment is also conveniently carried out at other parts of the blood vessel, the disease treatment effect is further improved, and meanwhile, doctors are allowed to carry out more complicated operation, and the operation effect is improved. However, after the external force is removed, the filtering structure can automatically return to the closed state to filter emboli, the normal emboli filtering capability of the blood vessel intervention stent is not influenced, and the use is convenient. And through being pipy bearing structure anchor fixedly in the blood vessel, anchoring ability reinforce, anchoring effect is good, makes this blood vessel intervene the support and need not to set up the faster condition of extra anchoring device just can adapt to the blood flow velocity again, can ensure that the blood vessel intervenes the fixed steadiness of support, and is safe in utilization reliable again. Moreover, the filtering structure is of an open 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 for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims.

Claims

1. A vascular interventional stent is characterized by comprising a supporting structure and a filtering structure; the support structure is tubular; the filtering structure is a net structure and is connected with the supporting structure; the filter structure has a closed state and an open state;

2. The vessel intervention stent of claim 1, wherein the filter structure comprises a plurality of filter rods, at least some of the filter rods are connected to the support structure at first ends thereof, and at least some of the filter rods are suspended at second ends thereof;

3. The vascular access stent of claim 2, wherein the first ends of the filter rods are arranged along the circumference of the support structure.

4. The vessel intervention stent of claim 3, wherein a first end of each filter rod is connected with the support structure, a second end of each filter rod is suspended, and the second ends of all the filter rods are close to each other and overlapped.

5. The vessel intervention stent of claim 2, wherein the filter rods are arranged in a planar radial arrangement, a three-dimensional radial arrangement or a planar checkerboard arrangement.

6. The interventional vascular stent of claim 5, wherein the filtering structure is dome-shaped or cone-shaped when the filtering rods are arranged in a radiating manner.

7. The interventional vascular stent of claim 5, 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 the first direction is disposed at a predetermined angle to the second direction such that the filter rods are arranged in a planar checkerboard pattern.

8. The vessel intervention stent of claim 7, wherein among all the filter rods extending along the first direction, both ends of a plurality of shorter filter rods are connected with the support structure, and first ends of a plurality of longer filter rods are connected with the support structure, and second ends of the plurality of longer filter rods are suspended;

9. The vessel intervention stent of claim 2, wherein among all the filter rods suspended at the second end, at least a part of the filter rods have a projection length on a radial plane of the support structure that satisfies the following requirements:

D/2≤L≤D

10. Vessel access stent according to any of claims 1-9, wherein the filtering structure is arranged at one end of the support structure;

11. The vascular access stent of claim 1, wherein the filtering structure is a unitary structure with the support structure.

12. The stent according to claim 11, wherein the filter structure and the support structure are integrally woven from woven filaments, or the filter structure and the support structure are integrally cut by laser.

13. The vessel intervention stent of claim 1, wherein the supporting structure is in a shape of a net tube and comprises a plurality of supporting rods, the expanded diameter of the supporting structure is 3.0mm to 6.0mm, and the included angle between the supporting rods and the radial cross section of the supporting structure is 10 degrees to 45 degrees.

14. The vascular interventional stent according to claim 13, wherein the expanded diameter of the support structure is 3.0mm to 4.5mm, and the included angle between the support rod and the radial cross section of the support structure is 30 ° to 35 °; or the diameter of the expanded supporting structure is 4.5 mm-5.5 mm, and the included angle between the supporting rod and the radial cross section of the supporting structure is 20-25 degrees; or the diameter of the expanded supporting structure is 5.5 mm-6.0 mm, and the included angle between the supporting rod and the radial cross section of the supporting structure is 10-15 degrees.

15. Vessel access stent according to claim 1, characterized in that 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.

16. A vascular access stent as claimed in claim 1, wherein the filtering structure comprises a plurality of filtering meshes, the maximum width of which does not exceed 0.2 mm.

17. The vascular access stent of claim 16, wherein a plurality of the filter meshes are distributed along the circumferential direction of the support structure, and the maximum width of the filter meshes along the circumferential direction is not more than 0.2 mm.

18. A vascular access stent as claimed in claim 16, wherein the plurality of filtering meshes are distributed along a first direction and a second direction, and the maximum width of the filtering meshes is not more than 0.2mm, and the first direction is disposed at a predetermined angle to the second direction.

19. The vascular access stent of claim 16, wherein the maximum width of the filter meshes is 0.15mm to 0.2 mm.

20. The vascular interventional stent of claim 1, wherein the vascular interventional stent is an intracranial vascular interventional stent.

21. The interventional vascular stent of claim 1, wherein the filter structure is transformed from the open state to the closed state by a self-elastic force when the external force applied to the filter structure is released.