CN114948364B

CN114948364B - A peripheral vascular stent and preparation method thereof

Info

Publication number: CN114948364B
Application number: CN202110208798.9A
Authority: CN
Inventors: 陆信武; 唐烈; 仇鹏; 叶开创; 秦金保; 王瑞华; 高成; 谢鹏
Original assignee: Polyrey Medical Tech Suzhou Co ltd
Current assignee: Polyrey Medical Tech Suzhou Co ltd
Priority date: 2021-02-25
Filing date: 2021-02-25
Publication date: 2025-07-15
Anticipated expiration: 2041-02-25
Also published as: CN114948364A

Abstract

The present invention relates to a peripheral vascular stent, which includes a plurality of support units and a membrane arranged at intervals, each support unit is formed by a silk thread and is in a closed ring shape, each support unit includes a plurality of peaks and valleys arranged periodically along the circumferential direction with the axis of the peripheral vascular stent as the axis, and two adjacent peaks form one period; the membrane is covered on the plurality of support units, the flexibility of the membrane is greater than the flexibility of the support unit, and a plurality of hollow areas are provided on the membrane between the silk threads of the same support unit and/or between two adjacent support units, and the two adjacent support units are connected only by the membrane outside the hollow area. The vascular stent of the present invention can meet the mechanical performance requirements of the lower limb artery under various deformation states, has a suitable radial support force and good flexibility, can well reduce the chronic outward expansion force in the vascular stent, and the vascular stent of the present invention has the advantages of small influence on blood flow, small damage to the inner wall of the blood vessel, and not easy to cause secondary thrombosis.

Description

Peripheral vascular stent and preparation method thereof

Technical Field

The invention belongs to the technical field of medical appliances, and particularly relates to a peripheral vascular stent and a preparation method thereof.

Background

Atherosclerosis-induced lower limb arteriosclerotic occlusive disease (PERIPHERAL ARTERY DISEASE, PAD) is the third atherosclerotic cardiovascular disease next to coronary heart disease, stroke. Over 3 million people worldwide suffer from PAD, and the evolution of this disease can cause lameness, rest pain, amputation, severely affecting the quality of life of the patient. The treatment method of PAD mainly includes medicine, open surgery and intracavitary intervention treatment modes. With the development of interventional therapy PAD, interventional therapy has proven to be less invasive and better in efficacy, and has become the primary way to treat PAD. The most common modes of endoluminal intervention are percutaneous transluminal balloon dilation and endoluminal stenting. The former has the defect that the patency rate of 1 year is only 28% -37%, and the latter has the defect that the short-term patency rate and the long-term patency rate of lesion blood vessels are obviously improved.

The current commonly used vascular stent mainly comprises two major types of cutting type and braiding type, wherein the braiding type stent is mainly woven by metal wires, and the cutting type stent comprises a plurality of closed rings which are axially distributed at intervals and are made of metal materials, and a connecting piece made of metal materials and used for connecting two adjacent closed rings. The woven stent has certain flexibility and fatigue resistance, but has very high axial shrinkage and relatively weak radial supporting force, while the cut stent has better radial supporting force and smaller axial shrinkage, but has poorer flexibility.

The peripheral vascular stent has unique physiological characteristics, pathological characteristics, kinematic mechanical characteristics, hydrodynamic characteristics and the like in addition to the lower limb artery of a human body, but the existing peripheral vascular stent cannot completely meet the unique requirements of the lower limb artery, and after the stent treatment, more than about 40 percent of patients can induce restenosis in the stent due to the chronic external expansion force of the stent and the low shear force in the stent. Under the condition that a certain radial supporting force is ensured, the peripheral vascular stent overcomes the mechanical factors such as chronic external expansion force, low shearing force and the like, but the existing peripheral vascular stent cannot meet the requirement, which is the most main reason for leading the re-intervention rate after the implantation operation of the peripheral vascular stent to be high.

Disclosure of Invention

The invention aims to provide a vascular stent with enough radial supporting force and good flexibility, which can be applied to peripheral blood vessels, and a preparation method thereof.

In order to achieve the above purpose, the invention adopts the following technical scheme:

in one aspect, the present invention provides a peripheral vascular stent having an expanded state and a contracted state, the peripheral vascular stent having an inner diameter in the expanded state that is greater than an inner diameter in the contracted state, the peripheral vascular stent comprising:

The support units are sequentially arranged at intervals along the axial direction of the peripheral vascular stent, each support unit is formed by a silk thread and is in a closed ring shape, each support unit comprises a plurality of peaks and valleys which are periodically arranged along the circumferential direction, and two adjacent peak tops are in a period;

The membrane is arranged on a plurality of supporting units in a covering mode, the flexibility of the membrane is larger than that of the supporting units, a plurality of hollowed-out areas are formed in the membrane between threads of one supporting unit and/or between two adjacent supporting units, and the two adjacent supporting units are connected through the membrane outside the hollowed-out areas.

Because the lower limb artery is different from other non-motile arterial blood vessels (such as coronary artery, carotid artery and aorta), the lower limb artery is in various deformation states under the action of the lower limb for a long time, such as popliteal artery after squatting, the shrinkage rate is 13-25%, the curvature radius after bending is 8-17mm, and the torsion degree is 14-26 degrees/cm. The arterial deformations after the movements can cause radial compression, torsion, buckling, axial stretching, compression and other effects on the stent, while the existing peripheral vascular stent is limited by a homogeneity design, so that the flexibility and the supporting force of the material cannot be simultaneously considered, and the characteristics of the lower limb artery cannot be simultaneously met. The vascular stent of the invention is superior to the limit of homogeneity design, a plurality of support units in the stent are not connected through a flexible membrane which is provided with a hollowed-out area, the flexible structure is connected with a fatigue damage which is not present in a metal connection structure on the first aspect, and the flexible structure has small irritation to endothelial cells in the shortening process, so that vascular damage is reduced, and the vascular stent can adapt to the shortening rate of arteries in various deformation states, the vascular stent of the invention can meet the deformation of peripheral blood vessels in a torsion state, and the irritation of the flexible structure to endothelial cells in the torsion process is small, so that vascular damage is reduced, the vascular stent of the invention has no 'fish scale phenomenon' and fatigue damage which are present in the flexible structure in the buckling state, particularly in peripheral blood vessels (such as popliteal artery and the like) of crotch joints, and the vascular stent of the structure can realize bending under small curvature radius and does not damage to vascular endothelium, and the fourth aspect, because the flexible connection is adopted, the vascular stent of the structure has enough axial stretching rate, and can meet the axial stretching deformation of the peripheral blood vessels, and the fifth aspect, the vascular stent of the invention adopts a plurality of annular support units in the axial spacing state, so that the vascular stent can provide enough supporting force and radial compression load to bear the peripheral blood vessel.

According to some specific and preferred embodiments, in two adjacent support units, one support unit and the other support unit are staggered on the circumferential surface, and the staggered distance is less than one half period, so that the vascular stent has better buckling, torsion, axial compression and stretching performances.

Further preferably, the offset distance is one quarter cycle or less.

Further preferably, each of the support units is staggered with an adjacent support unit on the circumferential surface along the clockwise direction by the same staggered distance, so that the support units can form a spiral-like structure as a whole, and the cross section of the vascular stent can be better maintained to be circular under the conditions of bending, torsion and the like, and the collapse of the vascular stent is avoided.

It should be noted that, the clockwise direction is only for convenience of description, and does not limit the protection scope of the present application, and the same technical effect can be achieved when the clockwise direction is along, and the present application is also within the protection scope of the present application.

According to some specific and preferred embodiments, the axis of each of the support units coincides with the axis of the peripheral vascular stent. The fact that the axis of each supporting unit coincides with the axis of the peripheral vascular stent in the application means that when the peripheral vascular stent comprises a main stent and a branch stent connected with the main stent, the axis of each supporting unit located in the main stent part coincides with the axis of the main stent, the axis of each supporting unit located in the branch stent part coincides with the axis of the branch stent, and when the peripheral vascular stent is not branched, the axis of each supporting unit coincides with the axis of the peripheral vascular stent.

According to some specific and preferred embodiments, the hollowed-out area comprises

A first hollowed-out part positioned in the peak of each supporting unit,

A second hollowed-out part positioned in the valley of each supporting unit,

The plurality of third hollowed-out parts are positioned between two adjacent supporting units and are respectively communicated with the first hollowed-out parts and the second hollowed-out parts; thereby leading the vascular stent to have better flexibility and be better buckled, twisted and the like along with the blood vessel.

In some embodiments, portions of the plurality of third hollowed-out portions between two adjacent support units may communicate with each other, but may not communicate entirely, resulting in separation between two adjacent support units without a membrane connection.

Further, each third hollowed-out part is only communicated with the nearest first hollowed-out part and the nearest second hollowed-out part, so that the connecting positions between two adjacent supporting units are more, and the connection between the two adjacent supporting units is firmer.

According to some specific and preferred embodiments, in two adjacent said support units, the valley bottom of one support unit is connected to the nearest peak top of the other support unit only by a strip-shaped membrane.

According to some more specific and preferred embodiments, the first hollow portion is surrounded by a first wall and a second wall, the upper end of which is connected, the second hollow portion is surrounded by a third wall and a fourth wall, the lower end of which is connected,

The third hollowed-out part is formed by encircling a fifth wall connected with the lower end of the first wall and the upper end of the fourth wall respectively and a sixth wall connected with the lower end of the second wall and the upper end of the third wall respectively.

Further preferably, the first hollow portion and the second hollow portion are as large as possible, and only the membrane is required to be guaranteed to cover the supporting units, in addition, because two adjacent supporting units are staggered, the first hollow portion and the second hollow portion are staggered, so that the hollow area forms two staggered and inverted triangles, the vascular stent has better flexibility, and buckling, torsion and the like along with blood vessels can be better performed.

Further preferably, when the peripheral vascular stent is cut along the axial direction and unfolded into a planar shape, two nearest first walls of two adjacent supporting units are on a first straight line, and the first straight line is obliquely arranged, so that the vascular stent can form a spiral-like structure, and the vascular stent can better maintain a circular cross section in bending, torsion and other states, and the collapse of the vascular stent is avoided.

Further preferably, the first wall forms an acute angle with the second wall.

Further preferably, the first wall and the third wall are parallel, the second wall and the fourth wall are parallel, and a plurality of the second walls are parallel.

According to some specific and preferred embodiments, the membrane is coated on the outer side or/and the inner side of the supporting unit, so that the intravascular stent has less influence on intravascular blood flow, thereby reducing the occurrence probability of blood flow disturbance and shear stress/shear rate abnormality after stent implantation, and further reducing the occurrence probability of a series of inflammation and vascular injury in a blood vessel. In addition, the soft membrane is covered outside the supporting unit, so that the application area of the vascular stent and the blood vessel is effectively increased, the extraction force of the vascular stent to the blood vessel is increased, and the chronic external expansion force of the vascular stent is reduced while the sufficient radial supporting force and good flexibility are maintained. On the one hand, the coating design closes the interlayer breach of the peripheral blood vessel to a certain extent, and on the other hand, the hollowed-out area is arranged on the surface film, so that compared with the full-coating design, the surface film can avoid completely covering the branch blood vessel, thereby being applicable to the peripheral blood vessel with more branch blood vessels, such as the popliteal artery.

According to some specific and preferred embodiments, the membrane comprises an inner membrane located inside the support unit and an outer membrane located outside the support unit, the inner membrane and the outer membrane are fixedly connected, and the support unit is coated between the inner membrane and the outer membrane.

Further, the inner film and the outer film in contact are heat-fused to integrally form the film.

According to some preferred embodiments, the inner diameter of the peripheral vascular stent in the unfolded state gradually decreases from one end to the other end, so that the physiological characteristic that the diameter of the artery of the lower limb of a human body is reduced in a conical shape is met, the application area of the vascular stent to the blood vessel is effectively increased, the chronic external expansion force of the stent is reduced, and the occurrence probability of restenosis in the stent is avoided.

According to some specific and preferred embodiments, the membrane is coated with a drug, thereby greatly increasing the drug attachment area and providing more drug attachment means, and the drug, including but not limited to a drug polymer carrier or active agent (e.g., bioactive agent), may be coated on the surface of the membrane to locally administer therapeutic substances, achieving anti-vascular proliferation and anti-endothelialization.

According to some specific and preferred embodiments, the material of the supporting unit is one or more of stainless steel, memory alloy, titanium alloy, tantalum alloy, cobalt-chromium alloy, biodegradable metal, biodegradable polymer, magnesium alloy, and pure iron, preferably nickel-titanium alloy.

According to some specific and preferred embodiments, the membrane is made of one or more of polytetrafluoroethylene, block polyether amide, polyimide, and bioabsorbable medical material, preferably, the membrane is a polytetrafluoroethylene microporous membrane.

The peripheral vascular stent is suitable for carrying out intravascular treatment on various peripheral blood vessels including superficial femoral arteries, iliac arteries, carotid arteries, radial arteries, lower limb arteries and the like. Among them, the peripheral vascular stent of the present invention is particularly suitable for vessels which undergo large deformation.

The support unit in the present invention may be a self-expanding or balloon-expanding support unit.

The second aspect of the present invention provides a method for preparing the peripheral vascular stent, wherein the membrane is fixed to the support unit, and then a plurality of hollow areas are formed on the membrane.

The third aspect of the present invention provides a method for preparing the peripheral vascular stent, wherein a plurality of hollowed areas are formed on the membrane, and then the membrane is fixed with the support unit.

According to a fourth aspect of the present invention, there is provided a method for preparing the peripheral vascular stent, wherein an inner membrane and an outer membrane are respectively disposed on the inner side and the outer side of a support unit, the support unit is wrapped between the inner membrane and the outer membrane by heating the inner membrane and the outer membrane, the inner membrane and the outer membrane outside the support unit are heat-fused into an integral membrane, and a plurality of hollowed-out areas are formed on the membrane.

In a fifth aspect of the present invention, there is provided a method for preparing the peripheral vascular stent, wherein a plurality of hollowed-out areas are formed on an inner membrane and an outer membrane, respectively, and then the inner membrane and the outer membrane are disposed on the inner side and the outer side of a support unit, respectively, and the hollowed-out areas on the inner membrane and the outer membrane are aligned, and the support unit is coated between the inner membrane and the outer membrane by heating, and the inner membrane and the outer membrane outside the support unit are heat-fused into a single film.

Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages:

The peripheral vascular stent can meet the mechanical performance requirements of peripheral blood vessels in various deformation states, can take account of proper radial supporting force and good flexibility, can well reduce chronic external expansion force in the peripheral vascular stent and reduce the occurrence rate of restenosis in the peripheral vascular stent, and has the advantages of small influence on blood flow, small damage to the inner wall of the blood vessels and difficult secondary thrombosis.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

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

Fig. 2 is a schematic structural view of a vascular stent according to embodiment 1 of the present invention, which is cut along an axial direction and deployed into a plane;

FIG. 3 is an enlarged view of a portion of a stent according to embodiment 1 of the present invention;

FIG. 4 is a cross-sectional view A-A of FIG. 3;

FIG. 5 is an enlarged view of a portion of FIG. 4;

FIG. 6 is a section B-B of FIG. 3;

FIG. 7 is an enlarged view of a portion of FIG. 6;

Fig. 8 is a schematic diagram of the vascular stent preparation process of example 1.

Detailed Description

Hereinafter, only certain exemplary embodiments are briefly described. As will be recognized by those of skill in the pertinent art, the described embodiments may be modified in numerous different ways without departing from the spirit or scope of the embodiments of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive.

In describing embodiments of the present invention, it should be understood that the terms "length," "inner," "upper," and the like indicate an orientation or a positional relationship based on the orientation or the positional relationship shown in fig. 1, only for convenience of describing embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements to be referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the embodiments of the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless explicitly defined otherwise.

In the embodiments of the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured" and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed, mechanically connected, electrically connected, or in communication, directly connected, or indirectly connected through an intermediary, or may be in communication with one another or an interaction relationship between two elements. The specific meaning of the above terms in the embodiments of the present invention will be understood by those of ordinary skill in the art according to specific circumstances.

In embodiments of the invention, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, or may include both the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is less level than the second feature.

The following disclosure provides many different implementations, or examples, for implementing different configurations of embodiments of the invention. In order to simplify the disclosure of embodiments of the present invention, components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit embodiments of the present invention. Furthermore, embodiments of the present invention may repeat reference numerals and/or letters in the various examples, which are for the purpose of brevity and clarity, and which do not themselves indicate the relationship between the various embodiments and/or arrangements discussed.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Example 1

Referring to fig. 1-8, in order to solve the problem that the existing vascular stent cannot well adapt to the requirement of a vessel having a large deformation in the movement process, such as a lower limb artery, the present embodiment provides a peripheral vascular stent comprising a plurality of supporting units 1 and a membrane 2.

As shown in fig. 1 and 2, a plurality of support units 1 are sequentially arranged at intervals along the axial direction of the peripheral vascular stent. Each supporting unit 1 is formed by wires and is in a closed ring shape, wherein the wires can be monofilaments formed by cutting and shaping a pipe or made in other forms, and can also be one wire formed by twisting and weaving a plurality of wires, the materials of the wires comprise one or more of stainless steel, memory alloy, titanium alloy, tantalum alloy, cobalt-chromium alloy, biodegradable metal, biodegradable polymer, magnesium alloy and pure iron, the supporting units 1 formed by the wires can be self-expanding supporting units or supporting units which can be expanded by means of a balloon or the like, and preferably, the wires adopt nickel-titanium alloy which can realize self expansion so as to provide better supporting force.

Each support unit 1 includes a plurality of peaks 11, valleys 12 which are periodically arranged in the circumferential direction with the axis of the peripheral vascular stent as the axis, and two adjacent peaks are one period. The shape of the filament constituting one cycle may be any shape having peaks and valleys, including, but not limited to, V-shape, U-shape, and the like. The axis of each supporting unit 1 coincides with the axis of the peripheral vascular stent. In order to adapt to the structure that the lower limb artery gradually becomes conical, the inner diameters of the supporting units 1 gradually become smaller from one end to the other end in the unfolding state, so that the physiological characteristic that the diameter of the lower limb artery of a human body is gradually reduced is met, the application area of a vascular stent to a blood vessel is effectively improved, the chronic external expansion force of the stent is reduced, and the occurrence probability of restenosis in the stent is obviously reduced.

As shown in fig. 1 and 2, the plurality of support units 1 are connected through the membrane 2 covered on the support units 1, and the flexibility of the membrane 2 is greater than that of the support units 1, so that the peripheral vascular stent adopts flexible connection, no fatigue damage exists in a metal connection structure, and the flexible structure has small irritation to endothelial cells in the processes of shortening, twisting, buckling, stretching and the like, thereby reducing vascular damage and meeting the shortening rate of arteries in various deformation states. The material of the membrane 2 includes but is not limited to polytetrafluoroethylene, block polyether amide, polyimide, and bioabsorbable medical materials, preferably the membrane 2 is polytetrafluoroethylene microporous membrane (ePTFE).

Wherein the membrane 2 may be a single layer membrane or a double layer membrane. When the membrane 2 is a single-layer membrane, the membrane 2 can be arranged on the inner side of the supporting unit 1 so as to reduce the influence of the peripheral vascular stent on blood flow as far as possible, and the membrane 2 can also be arranged on the outer side of the supporting unit 1 so as to increase the contact area between the peripheral vascular stent and the blood vessel wall and reduce the damage of the peripheral vascular stent on the blood vessel wall. Preferably, the membrane 2 is a double-layer membrane, that is, as shown in fig. 8, the membrane 2 includes an inner membrane 21 located inside the support unit 1 and an outer membrane 22 located outside the support unit 1, so that the influence of the peripheral vascular stent on the blood flow can be reduced, and the damage of the peripheral vascular stent on the blood vessel wall can be reduced.

In order to make the peripheral vascular stent capable of being better bent and twisted, a plurality of hollowed-out areas 23 are formed on the membrane 2 between the wires of the same supporting unit 1 and/or between two adjacent supporting units 1, so that when the vascular stent is bent or twisted, the hollowed-out areas 23 can provide avoidance space. In this embodiment, as shown in fig. 1 to 3, the hollowed-out areas 23 are formed on the film 2 between the threads of the same supporting unit 1 and between two adjacent supporting units 1. The support unit 1 is wrapped inside the membrane 2, and no support unit 1 protrudes to the hollowed-out area 23 and the support unit 1 is not directly contacted with the blood vessel wall, preferably, the area of the hollowed-out area 23 is set as large as possible.

Specifically, in the adjacent two support units 1, one support unit 1 and the other support unit 1 are provided with a stagger (peak staggering) on the circumferential surface, the stagger distance d is less than one half period, and preferably the stagger distance d is less than or equal to one quarter period. In this embodiment, as shown in fig. 2, the offset distance d is one quarter of a cycle. The stent shown in fig. 1 has a circumferential surface in cross section, and when the circumferential surface is viewed downward in the direction of fig. 1, the circumferential surface is aligned with the clockwise rotation direction, and each of the support units 1 is offset from the adjacent one of the support units 1 in the clockwise direction by the same distance, and it is, of course, expected by those skilled in the art that the stent obtained by the "offset from the adjacent one of the support units 1 in the counterclockwise direction by the same distance" can achieve the same effect. In order to more clearly illustrate the staggered structure between the two adjacent support units 1, as shown in fig. 2, when the peripheral vascular stent is cut along the axial direction thereof and unfolded into a plane, the next support unit 1 is always staggered towards the left side by the same distance relative to the previous support unit 1, so that the peak tops and peak tops, valley bottoms and valley bottoms, and peak tops and valley bottoms in the two adjacent support units are not aligned in the axial direction.

Specifically, as shown in fig. 2, each hollowed-out area 23 in the present embodiment includes a first hollowed-out portion 231 located in the peak 11 of each supporting unit 1, a second hollowed-out portion 232 located in the valley 12 of each supporting unit 1, and a third hollowed-out portion 233 located between two adjacent supporting units 1 and respectively communicating with the first hollowed-out portion 231 and the second hollowed-out portion 232. And, each third hollowed-out portion 233 is only connected with the nearest first hollowed-out portion 231 and the nearest second hollowed-out portion 232, and the hollowed-out areas 23 are mutually independent and not connected, so that in two adjacent supporting units 1, the valley bottom of one supporting unit 1 is connected with the nearest peak top of the other supporting unit 1 only through the strip-shaped film 2.

Further, the first hollow portion 231 is surrounded by a first wall 211 and a second wall 212, which are connected at the upper end, the second hollow portion 232 is surrounded by a third wall 213 and a fourth wall 214, which are connected at the lower end, and the third hollow portion 233 is surrounded by a fifth wall 215, which is connected with the lower end of the first wall 211 and the upper end of the fourth wall 214, and a sixth wall 216, which is connected with the lower end of the second wall 212 and the upper end of the third wall 213. The first walls 211 and the third walls 213 are parallel, the second walls 212 and the fourth walls 214 are parallel, the first walls 211 are parallel to each other, the second walls 212 are parallel to each other, and the included angle between the first walls 211 and the second walls 212 is an acute angle. As shown in fig. 2, when the peripheral vascular stent is cut along the axial direction thereof and expanded into a plane, the nearest two first walls 211 of the adjacent two support units 1 are on a first straight line L which is obliquely arranged, i.e., which intersects the longitudinal direction of the peripheral vascular stent. The staggered arrangement of the supporting units 1 and the structural design of the hollowed-out areas 23 enable the peripheral vascular stent to form a spiral-like structure, so that the peripheral vascular stent can better maintain a round shape on a cross section in bending, torsion and other states, collapse of the vascular stent is avoided, and the structural design enables the peripheral vascular stent to have better buckling, torsion, axial compression and stretching performances and better flexibility and radial supporting performance.

The preparation method of the peripheral vascular stent in the embodiment comprises the following steps:

The inner film 21 and the outer film 22 are respectively arranged on the inner side and the outer side of the supporting unit 1, the supporting unit 1 is coated between the inner film 21 and the outer film 22 by heating the inner film 21 and the outer film 22, the inner film 21 and the outer film 22 outside the supporting unit 1 are thermally fused into a whole to form a film 2, a plurality of hollowed-out areas 23 are formed on the film 2, or a plurality of hollowed-out areas 23 are respectively formed on the inner film 21 and the outer film 22, the inner film 21 and the outer film 22 are respectively arranged on the inner side and the outer side of the supporting unit 1, the hollowed-out areas 23 on the inner film 21 and the hollowed-out areas 23 on the outer film 22 are aligned, the supporting unit 1 is coated between the inner film 21 and the outer film 22 by heating, and the inner film 21 and the outer film 22 outside the supporting unit 1 are thermally fused into a whole to form the film 2.

In this embodiment, the outer surface of the inner membrane 21, the outer surface of the outer membrane 22, and the surfaces between the inner and outer membranes 21, 22 may be selectively coated with a drug, including but not limited to a drug polymer carrier or an active agent (e.g., a bioactive agent), to provide a substantially increased drug attachment area and manner, to locally administer a therapeutic substance, to achieve anti-vascular proliferation and anti-endothelialization.

Example 2 and example 3

The two embodiments are substantially the same as embodiment 1 except that the film 2 of embodiment 2 is a single-layer film provided on the inner side of the support unit 1, and the film 2 of embodiment 3 is a single-layer film provided on the outer side of the support unit 1.

The preparation method of the peripheral vascular stent of the two embodiments comprises the following steps:

The membrane 2 and the supporting unit 1 are fixed by means of hot melting, sewing and the like, and then a plurality of hollowed-out areas 23 are formed on the membrane 2, or a plurality of hollowed-out areas 23 are formed on the membrane 2, and then the membrane 2 and the supporting unit 1 are fixed by means of hot melting, sewing and the like.

The peripheral vascular stent has an expanded state and a contracted state, and the inner diameter in the expanded state is larger than the inner diameter in the contracted state. The structures of the peripheral vascular stent of the above embodiments 1 to 3 are described with the peripheral vascular stent in the expanded state.

The peripheral vascular stent of the 3 embodiments is stored in the delivery mechanism and is in a contracted state in the process of being delivered into a blood vessel, and after the delivery mechanism is retracted when the peripheral vascular stent is delivered to a required position of the blood vessel, the peripheral vascular stent is automatically unfolded to an unfolded state so as to support the blood vessel.

According to the vascular stent, the plurality of mutually independent supporting units 1 are connected through the flexible membrane 2 provided with the hollowed-out areas 23, and in the first aspect, the flexible structure is connected without fatigue damage of the metal connecting structure, and the flexible structure has small irritation to endothelial cells in the shortening process, so that vascular damage is reduced, and the vascular stent can adapt to the shortening rate of arteries in various deformation states; the vascular stent of the invention can adapt to deformation of peripheral blood vessels in a torsion state by the arrangement of the hollowed-out area 23, and has small irritation to endothelial cells in the torsion process, so that vascular damage is reduced, and has the advantages of no fish scale phenomenon and fatigue damage of the metal stent in a buckling state, and can realize bending under a small curvature radius without damaging vascular endothelium especially in the peripheral blood vessels of crotch joints (such as popliteal arteries and the like), and the vascular stent of the invention has enough axial stretching rate to meet the axial stretching deformation of the peripheral blood vessels by the arrangement of flexible connection, and has the advantages of providing enough radial supporting force by a plurality of closed annular supporting units 1 which are arranged at intervals along the axial direction, bearing the radial force of the peripheral blood vessels and crushing or pinching load and effectively supporting the arteries to provide enough blood flow.

The above embodiments are provided to illustrate the technical concept and features of the present invention and are intended to enable those skilled in the art to understand the content of the present invention and implement the same, and are not intended to limit the scope of the present invention. All equivalent changes or modifications made in accordance with the spirit of the present invention should be construed to be included in the scope of the present invention.

Claims

1. A peripheral vascular stent having an expanded state and a contracted state, the peripheral vascular stent having an inner diameter in the expanded state that is greater than an inner diameter in the contracted state, the peripheral vascular stent comprising:

The support units (1) are sequentially arranged at intervals along the axial direction of the peripheral vascular stent, each support unit (1) is formed by silk threads and is in a closed ring shape, each support unit (1) comprises a plurality of peaks (11) and valleys (12) which are periodically arranged along the circumferential direction, and two adjacent peaks are in a period;

The films (2) are arranged on a plurality of supporting units (1) in a covering mode, the flexibility of each film (2) is larger than that of each supporting unit (1), a plurality of hollowed-out areas (23) are formed in the films (2) between threads of the same supporting unit (1) and/or between two adjacent supporting units (1), and the two adjacent supporting units (1) are connected only through the films (2) except the hollowed-out areas (23) without metal connection;

In the two adjacent supporting units (1), one supporting unit (1) and the other supporting unit (1) are staggered on the circumferential surface, and the staggered distance is less than one half period;

The hollowed-out area (23) comprises:

A first hollowed-out part (231) positioned in the peak (11) of each supporting unit (1),

A second hollowed-out part (232) positioned in the valley (12) of each supporting unit (1);

and a plurality of third hollowed-out parts (233) which are positioned between two adjacent supporting units (1) and are respectively communicated with the first hollowed-out parts (231) and the second hollowed-out parts (232).

2. The peripheral vascular stent of claim 1 wherein the offset distance is one quarter cycle or less.

3. Peripheral vascular stent according to claim 2, wherein each of the support units (1) is offset from an adjacent one of the support units (1) in the clockwise direction by the same distance.

4. The peripheral vascular stent of claim 1, wherein the (1) axis of each support unit coincides with the axis of the peripheral vascular stent.

5. Peripheral vascular stent according to claim 1, wherein in two adjacent support units (1), the valley bottom of one support unit (1) and the nearest peak top of the other support unit (1) are connected only by a strip-shaped membrane (2).

6. The peripheral vascular stent according to claim 1, wherein the first hollow portion (231) is surrounded by a first wall (211) and a second wall (212) which are connected at the upper end portion, the second hollow portion (232) is surrounded by a third wall (213) and a fourth wall (214) which are connected at the lower end portion,

The third hollowed-out part (233) is formed by encircling a fifth wall (215) which is respectively connected with the lower end of the first wall (211) and the upper end of the fourth wall (214) and a sixth wall (216) which is respectively connected with the lower end of the second wall (212) and the upper end of the third wall (213).

7. Peripheral vascular stent according to claim 6, wherein the nearest two first walls (211) of the adjacent two support units (1) are on a first straight line when the peripheral vascular stent is cut along its axial direction and deployed in a planar shape.

8. The peripheral vascular stent of claim 6, wherein the first wall (211) is at an acute angle to the second wall (212).

9. The peripheral vascular stent of claim 6, wherein the first wall (211) and the third wall (213) are parallel, the second wall (212) and the fourth wall (214) are parallel, and a plurality of the second walls (212) are parallel.

10. Peripheral vascular stent according to claim 1, wherein the membrane (2) is wrapped on the outside or/and inside of the support unit (1).

11. The peripheral vascular stent according to claim 1, wherein the membrane (2) comprises an inner membrane (21) located inside the support unit (1) and an outer membrane (22) located outside the support unit (1), the inner membrane (21) and the outer membrane (22) are fixedly connected, and the support unit (1) is coated between the inner membrane (21) and the outer membrane (22).

12. Peripheral vascular stent according to claim 11, wherein the inner membrane (21) and the outer membrane (22) in contact are heat fused to form the membrane (2).

13. The peripheral vascular stent of claim 1, wherein the inner diameter of the peripheral vascular stent in the expanded state decreases gradually from one end to the other.

14. Peripheral vascular stent according to claim 1, wherein the membrane (2) is coated with a drug.

15. The peripheral vascular stent according to claim 1, wherein the material of the supporting unit (1) is one or more of stainless steel, memory alloy, titanium alloy, tantalum alloy, cobalt-chromium alloy, biodegradable metal, biodegradable polymer, magnesium alloy, pure iron.

16. Peripheral vascular stent according to claim 1, wherein the material of the support unit (1) is nitinol.

17. The peripheral vascular stent according to claim 1, wherein the membrane (2) is made of one or more of polytetrafluoroethylene, block polyether amide, polyimide, and bioabsorbable medical material.

18. Peripheral vascular stent according to claim 1, wherein the membrane (2) is a polytetrafluoroethylene microporous membrane.

19. A method of manufacturing a peripheral vascular stent as claimed in any of claims 1 to 18, wherein the membrane (2) is fixed to the support unit (1) and then a plurality of hollowed-out areas (23) are provided in the membrane (2).

20. A method of manufacturing a peripheral vascular stent as claimed in any of claims 1 to 18, wherein a plurality of hollowed-out areas (23) are provided in the membrane (2) and then the membrane (2) is secured to the support unit (1).

21. A method of manufacturing a peripheral vascular stent as claimed in any of claims 1 to 18, wherein an inner membrane (21) and an outer membrane (22) are provided on the inside and outside of the support unit (1), respectively, the support unit (1) is covered between the inner membrane (21) and the outer membrane (22) by heating the inner membrane (21) and the outer membrane (22), the inner membrane (21) and the outer membrane (22) outside the support unit (1) are heat fused together to form a membrane (2), and a plurality of hollowed-out areas (23) are provided on the membrane (2).

22. A method of manufacturing a peripheral vascular stent as claimed in any of claims 1 to 18, wherein a plurality of hollowed-out areas (23) are provided on an inner membrane (21) and an outer membrane (22) respectively, and then the inner membrane (21) and the outer membrane (22) are provided on the inner side and the outer side of a support unit (1) respectively, and the hollowed-out areas (23) on the inner membrane (21) and the hollowed-out areas (23) on the outer membrane (22) are aligned, and the support unit (1) is wrapped between the inner membrane (21) and the outer membrane (22) by heating, and the inner membrane (21) and the outer membrane (22) outside the support unit (1) are heat-fused into an integral membrane (2).