WO2023284595A1

WO2023284595A1 - Medical stent

Info

Publication number: WO2023284595A1
Application number: PCT/CN2022/104018
Authority: WO
Inventors: 黄云帆; 周炯
Original assignee: 神途医疗科技(上海)有限公司
Priority date: 2021-07-14
Filing date: 2022-07-06
Publication date: 2023-01-19
Also published as: CN115624423A

Abstract

A medical stent comprises a stent outer layer (1) and a stent inner layer (2). The stent outer layer (1) is a tubular body covering the stent inner layer (2) and formed by woven first filaments. The stent inner layer (2) comprises a thick filament (21) and a fine filament structure (22) which have opposite spiral directions and the same extension direction. The fine filament structure (22) has multiple interwoven rings (101) arranged in sequence along the extension direction. The thick filament (21) penetrates through the interwoven rings (101). The stent outer layer (1) is used to cover the plaque. Furthermore, the stent inner layer (2) formed by the spirally-extending thick filament (21) and fine filament structure (22) has excellent mechanical properties, large radial force, resistance to deformation and high flexibility, and can thus continuously expand narrowed blood vessels. Moreover, since the thick filament (21) penetrates through the interwoven rings (101) of the fine filament structure (22), the fine filament structure (22) can also provide a moving space for the thick filament (21) during bending while fixing the thick filament (21), and can also prevent deformation of the stent caused by excessive displacement of the thick filament (21).

Description

medical stent

technical field

The invention relates to the technical field of medical devices, in particular to a medical bracket.

Background technique

Carotid angioplasty and stenting (CAS) is a new minimally invasive and low-invasive interventional treatment developed in the past ten years, with high surgical efficiency and simple implementation. During the operation, a small puncture hole is made in the patient's femoral artery, the protective device is sent to the carotid artery through the catheter, and then the stent is placed to stretch the hardened and narrowed carotid artery. The entire operation does not take long, and the success rate exceeds 98%, which can effectively reduce the chance of ischemic stroke caused by carotid artery stenosis. The length of hospital stay for CAS surgery is short, especially for older patients who are not candidates for major surgery.

At present, the carotid stent is woven with a dense mesh, and the mesh is relatively large, usually more than 1 mm ² , which causes the plaque to fall easily after the stenosis is expanded, resulting in stroke. Moreover, in the prior art, the radial support force of the carotid artery stent braided with a dense mesh is relatively small, and it cannot well expand the hardened and narrowed carotid artery.

To sum up, in the prior art, the carotid stent has a large mesh and a small radial support force, and the effect of treating carotid stenosis is not good.

Contents of the invention

The purpose of the present invention is to provide a medical stent to solve the problem of large grid and small radial support force in the prior art carotid artery stent.

In order to solve the above technical problems, the present invention provides a medical stent: comprising: the outer layer of the stent and the inner layer of the stent; wherein,

The outer layer of the stent is a tubular body woven by first filaments covering the inner layer of the stent;

The inner layer of the stent includes a thick wire structure and a thin wire structure with opposite helical directions and the same extension direction. lock up.

Optionally, in the medical stent, a part or the whole of the inner layer of the stent is integrally braided with the outer layer of the stent.

Optionally, in the medical stent, along the axial direction of the outer layer of the stent, the inner layer of the stent is interwoven with the outer layer of the stent every set distance.

Optionally, in the medical stent, the inner layer of the stent includes 1-10 thick wires.

Optionally, in the medical stent, when the inner layer of the stent includes at least two thick wires, the thick wires do not intersect each other.

Optionally, in the medical stent, when the inner layer of the stent includes at least 2 thick wires, the tails of every n consecutive thick wires are connected, and n is a positive integer greater than 2.

Optionally, in the medical stent, the filament structure includes 2 second filaments, and the 2 second filaments rotate and interweave with each other to form a plurality of interweaving loops.

Optionally, in the medical stent, the inner layer of the stent includes a plurality of filament structures.

Optionally, in the medical stent, the plurality of filament structures do not intersect each other.

Optionally, in the medical stent, the thick wire, the second thin wire and the first thin wire are made of the same material, and the thick wire, the second thin wire, the The diameters of the first filaments decrease sequentially.

Optionally, in the medical stent, the outer layer of the stent is formed by weaving the first filaments in two directions at an angle to each other by sinking and floating by 1

interval

1, 1

interval

2 or 2 intervals 2 .

Optionally, in the medical stent, the grid area of the outer layer of the stent is 0.04mm ² -0.09mm ² .

In summary, the medical stent provided by the present invention includes that the outer layer of the stent is a tubular body woven from the first filament and covers the inner layer of the stent; the inner layer of the stent includes Thick filaments and thin filaments with the same extension direction, the filament structure has a plurality of interweaving loops arranged in sequence along the extension direction, and the thick filaments are threaded through the plurality of interweaving loops.

Compared with the prior art, it has the following advantages:

(1) The outer layer of the stent bears the role of covering the plaque in the blood vessel, while the inner layer of the stent formed by the helical extension of the thick wire and the thin wire structure has better mechanical properties, large radial force, and resistance Deformation, but also high flexibility, can continuously dilate blood vessels in narrowed areas;

(2) The thick wire is threaded through the interweaving circle of the thin wire structure, and the thin wire structure can not only fix the thick wire, but also provide a moving space for the thick wire when bending, and It can prevent the deformation of the bracket caused by the excessive displacement of the thick wire;

(3) Further, part or the whole of the inner layer of the stent is integrally braided with the outer layer of the stent, so that the inner layer of the stent will not be detached from the outer layer of the stent, thereby achieving high stability of the stent.

Description of drawings

Fig. 1 is the structural representation of the medical stent provided by the embodiment of the present invention;

Figure 2a is a schematic diagram of the non-interlaced part of the stent outer layer and the stent inner layer of the medical stent provided by the embodiment of the present invention;

Fig. 2b is a schematic diagram of the interweaving part of the stent outer layer and the stent inner layer of the medical stent provided by the embodiment of the present invention;

Fig. 3 is a schematic structural view of the inner layer of the stent comprising two thick wires in an embodiment of the present invention;

Fig. 4 is a schematic view of the state of the thick wire when the medical stent provided by the embodiment of the present invention is bent;

Fig. 5 is a schematic diagram of the effect of the open-loop stent shown in the embodiment of the present invention;

Fig. 6 is a structural schematic diagram of the filament structure described in the embodiment of the present invention;

Fig. 7 is a schematic diagram of the connection state between the thick wires in the embodiment of the present invention;

Fig. 8 is a weaving structure diagram of the outer layer of the stent in the embodiment of the present invention;

Fig. 9a is a schematic diagram of the first weaving method of the outer layer of the stent in the example of the embodiment of the present invention;

Fig. 9b is a schematic diagram of the second weaving method of the outer layer of the stent in the example of the embodiment of the present invention;

Fig. 9c is a schematic diagram of the third weaving method of the outer layer of the stent according to the embodiment of the present invention;

Wherein, each reference sign is explained as follows:

1-outer layer of stent; 2-inner layer of stent; 3-vascular wall; 4-braided mandrel;

21-coarse filament; 22-fine filament structure;

101 - interweaving circle;

201 - connection part.

detailed description

In order to make the purpose, advantages and features of the present invention clearer, the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in very simplified form and not drawn to scale, and are only used to facilitate and clearly assist the purpose of illustrating the embodiments of the present invention. In addition, the structures shown in the drawings are often a part of the actual structures. In particular, each drawing needs to display different emphases, and sometimes uses different scales. It should also be understood that, unless otherwise specified or pointed out, the terms “first”, “second”, “third” and other descriptions in the specification are only used to distinguish each component, element, step, etc. in the specification, rather than It is used to express the logical relationship or sequence relationship between various components, elements, and steps.

Please refer to FIG. 1 , an embodiment of the present invention provides a medical stent, which is characterized in that it includes: a stent outer layer 1 and a stent inner layer 2; wherein,

The stent outer layer 1 is a tubular body covered with the stent inner layer 2 woven by first filaments;

The stent inner layer 2 includes thick wires 21 and thin wire structures 22 with opposite helical directions and the same extension direction; a plurality of said interweaving loops.

In the medical stent provided by the embodiment of the present invention, the outer layer 1 of the stent bears the role of plaque coverage, and the inner layer 2 of the stent formed by the helical extension of the thick wire 21 and the thin wire structure 22 has better excellent mechanical properties, large radial force, resistance to deformation, and high flexibility, which can continuously dilate blood vessels in narrowed places; in addition, since the thick wire 21 is threaded through the interweaving circle 101 of the thin wire structure 22, the The thin wire structure 22 not only fixes the thick wire 21, but also provides a moving space for the thick wire 21 when it is bent, and prevents the bracket from being deformed due to excessive displacement of the thick wire 21.

In this embodiment, when forming the inner layer 2 of the stent, the thick wire 21 and the thin wire structure 22 can be integrally braided on the braided mandrel 4, and then the braided mandrel 4 is pulled out of the stent formed by braiding. Pull out. And preferably, part or the whole of the stent inner layer 2 is integrally braided with the stent outer layer 1, so that the stent inner layer 2 will not be detached from the stent outer layer 1 to achieve high stability of the stent sex. Optionally, the stent inner layer 2 is integrally braided with the stent outer layer 1 through a part or the whole of the thick wire 21 , and/or, a part or the whole of the thin wire structure 22 and the stent outer layer 1 .

In this embodiment, preferably, the stent outer layer 1 interweaves with the stent inner layer 2 at some positions, and the stent outer layer 1 interweaves with the thick wire 21 in the stent inner layer 2 at some positions. Compared with the interweaving of the outer layer 1 of the stent with the inner layer 2 of the stent at all positions and the inner layer 2 of the stent through filaments, the difficulty of weaving can be reduced due to the reduced number of interweaving times.

When the medical stent provided in this embodiment is applied, please refer to Fig. 2a and Fig. 2b, where the stent outer layer 1 is not interwoven with the stent inner layer 2, the stent outer layer 1 is close to the blood vessel wall 3; please Referring to Fig. 2b, at the position where the stent outer layer 1 and the stent inner layer 2 interweave, the stent inner layer 2 is close to the vessel wall 3, specifically, in the stent outer layer 1 and the stent inner layer At the position where the layers 2 are interwoven, the thick filaments 21 in the inner layer 2 of the stent are tightly attached to the vessel wall 3 .

Further preferably, along the axial direction of the stent outer layer 1, the stent inner layer 2 interweaves with the stent outer layer 1 every set distance apart, that is, every set distance apart, the stent inner layer 2 The thick filaments 21 of layer 2 are interwoven with the outer layer of the stent. In this way, when the stent inner layer 2 is bent, the acting force between the stent inner layer 2 and the stent outer layer 1 can be uniform, thereby improving the overall reliability of the stent. Wherein, the set distance can be specifically designed according to the axial length of the bracket. In this embodiment, the set distance can be 1/2 of the total axial length of the bracket. In this way, at the middle position of the bracket, the The inner layer 2 of the stent is interwoven with the outer layer 1 of the stent, and at both ends of the stent, the inner layer 2 of the stent is interwoven with the outer layer 1 of the stent, so the set distance is the total axial length of the stent 1/2 of the stent, when the axial length of the stent becomes longer, the set distance, for example, can also be 1/3, 1/4, etc. of the total axial length of the stent, that is to say, when the axial length of the stent The longer the distance is, the smaller the ratio of the set distance to the total axial length of the stent is, so that the force between the inner layer 2 of the stent and the outer layer 1 of the stent can be ensured to be uniform.

Optionally, the stent inner layer 2 includes one thick wire 21 , and preferably, the one thick wire 21 has no intersection point on the extending path. Alternatively, the stent inner layer 2 includes two or more thick wires 21 extending helically in the same direction, preferably, one or more thick wires 21 extending helically in the same direction do not intersect each other; The combined use of two or more than two thick wires 21 enables the stent to have a good uniform support effect. Each of the thick wires 21 forms a helical structure, and the helical structures do not intersect each other. The existence of the helical structure makes the stent It has good flexibility and adhesion. In this embodiment, preferably, the stent inner layer 2 includes 1 to 10 thick wires 21, and the number of thick wires 21 can be selected according to the target support force of the stent and the thick wires 21 themselves. tuned performance characteristics.

Fig. 3 is an example that the stent layer contains 2 thick wires 21. According to this design, the stent processed at a braiding angle of 45° (the angle between the wire and its axial direction) has a high resistance to bending deformation. B/A is greater than 95%, see Figure 5, where B is the diameter of the bend, and A is the diameter of both ends of the bend.

Please refer to Fig. 4, since there is no intersection point between the helical structures formed by the thick filaments 21, the stent will not be bent when bent, similar to the effect shown in Fig. 5, when the bending angle is large, the bent Small changes in the diameter of the stent at this location allow for high compliance. Further, in order to ensure that the helical structures formed by each of the thick filaments 21 do not intersect with each other, the helical structures formed by each of the thick filaments 21 can be set to have the same helix angle; in other embodiments, the The thick filaments 21 have different helix angles, and there are intersection points between the thick filaments 21 .

Please refer to Fig. 6. In this embodiment, the filament structure 22 includes 2 second filaments, and the 2 second filaments rotate and interweave with each other to form multiple interweaving points. An interweaving loop 101 is formed between them, so that the filament structure 22 has a plurality of interlacing loops 101 arranged in sequence along the helical extension direction. In addition, preferably, the stent inner layer 2 includes a plurality of filament structures 22 . More preferably, the plurality of filament structures 22 do not intersect each other, that is, each filament structure 22 forms a helical structure, and the helical structures formed by each filament structure 22 do not intersect each other. In other embodiments, intersections exist between the plurality of filamentary structures. The multiple thin wire structures 22 are designed so that when the helical structure formed by the thick wires 21 is bent, each part can be limited in displacement by the thin wires, so that the stent can be deformed within a target range.

In some embodiments, the size of the interweaving loops 101 may be uniform or non-uniform. In some embodiments, the thick filaments 21 pass through all the interlaced loops 101 of the thin filament structure 22 ; in other embodiments, the thick filaments 21 pass through part of the interwoven loops 101 of the filament structure 22 . In some embodiments, one thick wire 21 is passed through a single interweaving loop 101; 2 or 3 of the thick filaments are threaded in the interweaving loops 101; Describe thick silk 21.

Figure 6 illustrates an embodiment of the specific weaving structure of the inner layer of the stent 2, the thick wire 21 spirals in one direction to form a helical structure, and the second thin wire spirals in the opposite direction to the thick wire 21. Helical in the other direction, every two second filaments are twisted and intertwined with each other to form several interweaving points, and the thick filaments 21 run through between the two interweaving points, this structure can prevent the thick filaments 21 from occurring displacement in the axial direction. In some other embodiments, the interweaving point formed by the intertwining and intertwining of the second filaments may contain multiple twisting knots, for example, the interweaving point between two filaments is formed by two twisting knots. In other embodiments, each plurality of second filaments are intertwined and intertwined with each other to form several intertwined points, for example, three or four of the second filaments are intertwined and intertwined with each other to form intertwined points.

In addition, referring to FIG. 7 , preferably, when the stent inner layer 2 includes at least two thick wires 21 , the tails of every n consecutive thick wires 21 are connected to form a connecting portion 201 , wherein, n is a positive integer greater than 2, that is to say, a connecting portion can be formed by connecting the tails of every two adjacent thick wires 21 , or a connecting portion can be formed by connecting the tails of every consecutive thick wires 21 , or, the tails of all the thick wires 21 are connected to form a connecting portion. When the tails of the thick wires 21 are connected, the thick wires 21 and the second thin wires may be prevented from being detached from each other due to excessive bending deformation.

Further preferably, the tails of the thick filaments 21 are smoothed to form smooth edges and prevent blood vessels from being punctured. In some embodiments, the tails of all the thick wires 21 may be welded to form smooth edges. In some other embodiments, the tail of the thick wire 21 may also be cut directly and then smoothed. The way of the smoothing treatment can be, for example, grinding treatment, coating, etc., and the application does not limit the way of smoothing the tail of the thick wire 21 .

Please refer to FIG. 8 , in this embodiment, the outer layer 1 of the stent is a fabric structure braided by the first filaments in two directions at angles to each other. Preferably, when weaving and forming, as shown in Figure 9a, the first filaments in the two directions at an angle to each other sink and float at intervals of one at a time, and as shown in Figure 9b, the two angles at each other The first filaments in one direction sink and float with each other at intervals of 2, or as shown in FIG. The mesh area of the outer layer 1 of the stent is 0.04mm ² -0.09mm ² , which has a good effect in preventing the thrombus falling from the plaque from escaping. In some other embodiments, other weaving methods can also be selected to form the outer layer 1 of the stent. In this application, there is no limit to the method of forming the outer layer 1 of the stent by weaving, as long as the outer layer 1 of the stent is ensured. The grid area may be within the range of 0.04mm ² to 0.09mm ² .

In this embodiment, the thick wire 21, the second thin wire and the first thin wire can be made of the same material, such as cobalt-chromium alloy, nickel-titanium alloy, tungsten wire, and stainless steel wire. In the manner, the thick wire 21, the second thin wire and the first thin wire can be made of different materials, for example, the thick wire 21, the second thin wire and the first thin wire are respectively made of Any one of cobalt-chromium alloy, nickel-titanium alloy, tungsten wire, stainless steel wire, and metal composite wire. In some other embodiments, any one or several of the thick wire 21, the second thin wire, and the first thin wire is made of radiopaque developing wire, such as platinum wire, platinum tungsten wire, platinum wire, etc. Any one or several kinds of developing filaments such as iridium filaments. In this embodiment, the diameters of the thick wire 21, the second thin wire, and the first thin wire decrease sequentially, so that the hardness of the thick wire 21 is greater than the hardness of the second thin wire > the hardness of the first thin wire, so that the thick wire 21 with a relatively large wire diameter can be used to provide structural support for expanding outward against the blood vessel, and the second wire with a relatively small diameter can be used The thin wires limit the degree of bending or compression of the thick wires 21, so that the overall stent is not easily deformed, and the outer layer 1 of the braided stent meets the requirements of 0.04 mm ² to 0.09 mm by using the first thin wire with the smallest wire diameter. mm ² grid area requirements. In some other embodiments, the diameter of the thick wire 21 is the largest, and the diameters of the second thin wire and the first thin wire may be the same.

In a specific embodiment, the diameter of the thick wire 21 may be 4/1000-6/1000 inch, the diameter of the second thin wire may be 21/10000-35/10000 inch, the first The diameter of the filaments can be 10/10000-16/10000 inch.

In summary, the medical stent provided by the present invention includes: an outer layer of a stent and an inner layer of a stent; wherein, the outer layer of the stent is a tubular body woven from a first filament covering the inner layer of the stent ; the inner layer of the stent includes a thick wire structure and a thin wire structure with opposite helical directions and the same extension direction, the thin wire structure has a plurality of interweaving circles arranged in sequence along the extension direction, and the thick wire passes through a plurality of the interwoven circles. In the medical stent provided by the present invention, the outer layer of the stent bears the role of covering the plaque, while the inner layer of the stent formed by the helical extension of the thick wire and the thin wire structure has better mechanical properties, radial Strong force, resistance to deformation, and high flexibility at the same time, can continuously expand the narrowed blood vessels; in addition, because the thick wire is passed through the interweaving circle of the thin wire structure, the thin wire structure can fix the At the same time, the thick wires can also provide a moving space for the thick wires when they are bent, and can prevent the deformation of the stent caused by excessive displacement of the thick wires.

It should be noted that the medical stent provided by the present invention can be used in the carotid artery, and can also be applied to other parts in need, such as the subclavian artery, vertebral artery ostium, intracranial blood vessels, peripheral blood vessels, coronary arteries, etc. Applications are not limited to this.

In addition, it should be understood that although the present invention has been disclosed above with preferred embodiments, the above embodiments are not intended to limit the present invention. For any person skilled in the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or be modified into equivalent changes, etc. effective example. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention, which do not deviate from the content of the technical solution of the present invention, still belong to the scope of protection of the technical solution of the present invention.

Claims

A medical stent, characterized in that it comprises: an outer layer of the stent and an inner layer of the stent; wherein,

The outer layer of the stent is a tubular body woven by first filaments covering the inner layer of the stent;

The inner layer of the stent includes a thick wire structure and a thin wire structure with opposite helical directions and the same extension direction. lock up.
The medical stent according to claim 1, wherein a part or the whole of the inner layer of the stent is integrally braided with the outer layer of the stent.
The medical stent according to claim 2, wherein the inner layer of the stent and the outer layer of the stent interweave each other at a set distance along the axial direction of the outer layer of the stent.
The medical stent according to claim 1, wherein the inner layer of the stent comprises 1 to 10 thick wires.
The medical stent according to claim 4, wherein when the inner layer of the stent includes at least two thick wires, the thick wires do not intersect each other.
The medical stent according to claim 4, wherein when the inner layer of the stent includes at least 2 thick wires, the tails of every n consecutive thick wires are connected, and n is a positive integer greater than 2 .
The medical stent according to claim 1, wherein the filament structure comprises two second filaments, and the two second filaments rotate and interweave with each other to form a plurality of interweaving loops.
The medical stent according to any one of claims 1-7, wherein the inner layer of the stent comprises a plurality of filament structures.
The medical stent according to claim 8, wherein the plurality of filament structures do not intersect each other.
The medical stent according to claim 6, wherein the thick wire, the second thin wire and the first thin wire are made of the same material, and the thick wire, the second thin wire , The diameters of the first filaments decrease sequentially.
The medical stent according to claim 1, wherein the outer layer of the stent consists of the first filaments in two directions at an angle to each other by sinking and floating by 1 interval 1, 1 interval 2 or 2 intervals 2 Woven to shape.
The medical stent according to claim 1 or 11, wherein the grid area of the outer layer of the stent is 0.04mm 2 -0.09mm 2 .