CN114948364A

CN114948364A - Peripheral vascular stent and preparation method thereof

Info

Publication number: CN114948364A
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: 2022-08-30

Abstract

The invention relates to a peripheral vascular stent, which comprises a plurality of supporting units and a membrane which are arranged at intervals, wherein each supporting unit is formed by silk threads and is in a closed ring shape, each supporting unit comprises a plurality of peaks and valleys which take the axial lead of the peripheral vascular stent as the axis and are periodically arranged along the circumferential direction, and two adjacent peaks are in a period; the membrane covers and establishes on a plurality of supporting element, and the flexibility of membrane is greater than the flexibility of supporting element, has seted up a plurality of fretwork areas on the membrane between the silk thread of same supporting element and/or between two adjacent supporting element, and two adjacent supporting element only connect through the membrane outside the fretwork area. The intravascular stent can meet the mechanical performance requirements of lower limb arteries in various deformation states, has proper radial supporting force and good flexibility, and can well reduce the chronic outward expansion force in the intravascular stent.

Description

Peripheral vascular stent and preparation method thereof

Technical Field

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

Background

Atherosclerosis-induced lower extremity atherosclerotic occlusion (PAD) is the third atherosclerotic cardiovascular disease second only to coronary heart disease, stroke. More than 3 million people worldwide suffer from PAD, and the progression of the disease can cause lameness, rest pain and amputation, which seriously affects the quality of life of patients. The treatment methods of PAD mainly comprise medicine, open surgery and intracavity intervention treatment. As the intervention for PAD has progressed, it has proven to be less traumatic and more effective, and has become the primary means of treating PAD. The two most common modes of endoluminal intervention are percutaneous transluminal balloon dilatation and endoluminal stenting. The former has the disadvantage that the patency rate is only 28-37% in 1 year, and the appearance of the latter obviously improves the near-far patency rate of diseased vessels.

The currently commonly used vascular stents mainly include two types, namely a cutting type stent and a weaving type stent, wherein the weaving type stent is mainly formed by weaving metal wires, and the cutting type stent comprises a plurality of closed rings which are distributed at intervals along the axial direction and are made of metal materials, and a connecting piece which is made of metal materials and is used for connecting two adjacent closed rings. The braided stent has certain flexibility and fatigue resistance, but the axial shrinkage rate is very high and the radial supporting force is relatively weak; the cutting type stent has better radial supporting force and smaller axial shrinkage, but has poorer flexibility.

The peripheral vascular stent has unique physiological characteristics, pathological characteristics, motion mechanics characteristics, hydromechanics characteristics and the like of lower limb arteries of a human body, but the existing peripheral vascular stents cannot completely meet the unique requirements of the lower limb arteries, and after the lower limb artery diseases are treated by the stent, about more than 40 percent of patients can induce in-stent restenosis due to the chronic external expansion force of the stent and low shearing force in the stent. The peripheral vascular stent needs to overcome mechanical factors such as chronic outward expansion force and low shearing force under the condition of ensuring a certain radial supporting force, but the existing peripheral vascular stent can not meet the requirement, which is the most main reason for leading the intervention rate after the peripheral vascular stent implantation operation to be high.

Disclosure of Invention

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

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

the invention provides a peripheral blood vessel support which has an expansion state and a contraction state, wherein the inner diameter of the peripheral blood vessel support in the expansion state is larger than that in the contraction state; the peripheral vascular stent includes:

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

the membrane, the membrane covers and establishes on a plurality of the supporting element, the flexibility of membrane is greater than the flexibility of supporting element, same between the silk thread of supporting element and/or adjacent two between the supporting element a plurality of fretwork regions have been seted up on the membrane, adjacent two the supporting element only passes through outside the fretwork region the membrane is connected.

Since the lower limb artery is different from other non-moving artery vessels (such as coronary artery, carotid artery and aorta), it is in various deformed states for a long time under the action of lower limbs, such as popliteal artery after squatting: the short shrinkage is 13-25%, the curvature radius after bending is 8-17mm, and the torsion degree is 14-26 degrees/cm. The artery deformation after the movement can cause the effects of radial compression, torsion, buckling, axial stretching, compression and the like on the stent, and the existing peripheral vascular stent is limited by homogeneous design, so that the flexibility and the supporting force of the material cannot be considered at the same time, and the characteristics of the lower limb artery cannot be met at the same time. The vascular stent of the invention surpasses the limitation of homogeneity design, a plurality of supporting units in the stent are not connected by metal, and are only connected by a flexible membrane which is provided with a hollow area, on the one hand, the flexible structure is connected with the fatigue damage which is not existed in the metal connecting structure, and the flexible structure has small irritation to endothelial cells in the shortening process, thereby reducing the vascular damage and being capable of adapting to the shortening rate of the artery in various deformation states; in the second aspect, the vascular stent with the structure can meet the deformation of peripheral blood vessels in a twisting state, and the flexible structure has small irritation to endothelial cells in the twisting process, so that the vascular injury is reduced; in a third aspect, the vascular stent of the structure does not have the fish scale phenomenon and fatigue injury existing in a metal stent in a buckling state, and particularly in peripheral blood vessels of a hip joint (such as popliteal artery and the like), the vascular stent can be bent under a small curvature radius without damaging the endothelium of the blood vessels; in the fourth aspect, the vascular stent of the structure of the invention adopts flexible connection, so that enough axial stretching rate exists, and the axial stretching deformation of peripheral blood vessels can be met; in the fifth aspect, the vessel stent of the present invention employs a plurality of closed loop-shaped supporting units arranged at intervals in the axial direction, so that sufficient radial supporting force can be provided, and the vessel stent can bear the radial force and the crushing or pinching load of the peripheral vessel, and effectively support the artery to provide sufficient blood flow.

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

Further preferably, the staggered distance is equal to or less than one-quarter of a period.

Further preferably, in the clockwise direction, each of the supporting units and an adjacent supporting unit are arranged in a staggered manner on the circumferential surface and have the same staggered distance, so that the supporting 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 in the bending, twisting and other states, and the vascular stent is prevented from collapsing.

It should be noted that the clockwise direction is only for convenience of description and is not to be construed as a limitation of the protection scope of the present application, and the same technical effect can be achieved when the counterclockwise direction 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 coincidence of the axial lead of each support unit and the axial lead of the peripheral vascular stent in the application means that: when the peripheral vascular stent comprises a main stent and a sub-stent connected with the main stent, the axis of the supporting unit positioned on the main stent part is superposed with the axis of the main stent, and the axis of the supporting unit positioned on the sub-stent part is superposed with the axis of the sub-stent; when the peripheral blood vessel stent is not branched, the axial lead of each supporting unit is superposed with the axial lead of the peripheral blood vessel stent.

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

A first hollow part positioned in the peak of each supporting unit,

A second hollow part positioned in the valley of each supporting unit,

The plurality of third hollow parts are positioned between two adjacent supporting units and are respectively communicated with the first hollow parts and the second hollow parts; therefore, the vascular stent has better flexibility and can better flex, twist and the like along with the blood vessel.

In some embodiments, the portions of the plurality of third hollow portions between two adjacent supporting units may be communicated with each other, but not all of the portions may be communicated with each other, so that two adjacent supporting units are separated without membrane connection.

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

According to some specific and preferred embodiments, in two adjacent supporting units, the valley bottom of one supporting unit is connected with the nearest peak top of the other supporting unit only through a strip-shaped film.

According to some more specific and preferred embodiments, the first hollowed-out portion is defined by a first wall and a second wall connected by an upper end portion, the second hollowed-out portion is defined by a third wall and a fourth wall connected by a lower end portion,

the third hollow-out part is formed by surrounding a fifth wall which is respectively connected with the lower end of the first wall and the upper end of the fourth wall, and a sixth wall which is respectively connected with the lower end of the second wall and the upper end of the third wall.

Further preferably, first fretwork portion with second fretwork portion is as big as possible, only need to guarantee that the membrane will the supporting element cladding can, in addition, because adjacent two the supporting element setting of staggering, consequently, first fretwork portion and second fretwork portion also set up of staggering to make the fretwork region form two triangles of staggering and invering, thereby make vascular support have better compliance, can be better buckle along with the blood vessel, twist etc..

Further preferably, when the peripheral blood vessel stent is cut along the axial direction thereof and expanded into a plane shape, the two nearest first walls of the two adjacent support units are on a first straight line, and the first straight line is obliquely arranged, so that the blood vessel stent can form a spiral-like structure, and the blood vessel stent can better maintain a circular cross section in a bending state, a twisting state and the like, and avoid the blood vessel stent from collapsing.

Further preferably, the included angle between the first wall and the second wall is an acute angle.

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 disorder and shear stress/shear rate abnormality after stent implantation, and further reducing the occurrence probability of a series of inflammations and vascular injuries in blood vessels. In addition, the soft membrane is arranged outside the supporting unit, so that the attaching area of the vascular stent and the blood vessel is effectively increased, the pull-out force of the vascular stent on the blood vessel is increased, and the chronic outward expansion force of the vascular stent is further reduced while the sufficient radial supporting force and the good flexibility are maintained. On one hand, the tectorial membrane is designed to seal the interlayer lacerations of the peripheral blood vessels to a certain extent; and a hollow area is arranged on the mask on the other side, so that the mask can avoid completely covering branch blood vessels compared with a full-film-covered design, and is suitable for peripheral blood vessels with more branch blood vessels, such as 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 being fixedly connected, and the support unit being enclosed between the inner membrane and the outer membrane.

Further, the inner film and the outer film which are 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 expanded 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 tapered manner is met, the application area of the vascular stent to the blood vessel is effectively increased, the chronic outward 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 area of drug attachment and providing more drug attachment, and the surface of the membrane may be coated with a drug including, but not limited to, a drug polymer carrier or an active agent (e.g., a bioactive agent), locally administering a therapeutic substance, and 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, and is preferably nickel-titanium alloy.

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

The peripheral vascular stent is suitable for intravascular treatment of various peripheral blood vessels including superficial femoral artery, iliac artery, carotid artery, radial artery, lower limb artery and the like. Among them, the peripheral vascular stent of the present invention is particularly suitable for blood vessels that are subject to large deformation.

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

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

The third aspect of the invention is to provide a method for preparing the peripheral vascular stent, wherein a plurality of hollow areas are arranged on the membrane, and then the membrane is fixed with the supporting unit.

The fourth aspect of the present invention provides a method for preparing the peripheral vascular stent, wherein an inner membrane and an outer membrane are respectively arranged on the inner side and the outer side of a supporting unit, the supporting unit is coated 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 supporting unit are thermally fused into a whole to form a membrane, and a plurality of hollow areas are formed on the membrane.

The fifth aspect of the present invention provides a method for preparing the peripheral vascular stent, wherein a plurality of hollowed regions are respectively formed on an inner membrane and an outer membrane, then the inner membrane and the outer membrane are respectively arranged on the inner side and the outer side of a supporting unit, the hollowed regions on the inner membrane and the hollowed regions on the outer membrane are aligned, the supporting unit is wrapped between the inner membrane and the outer membrane by heating, and the inner membrane and the outer membrane outside the supporting unit are heat-fused into a whole to form a membrane.

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 give consideration to proper radial supporting force and good flexibility, can well reduce the chronic outward expansion force in the peripheral vascular stent and reduce the incidence 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 a blood vessel and difficult secondary thrombosis.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a perspective view of a vascular stent provided in example 1 of the present invention;

FIG. 2 is a schematic structural view of the blood vessel stent provided in example 1 of the present invention, which is axially cut and expanded into a plane;

FIG. 3 is a partially enlarged view of a vascular stent provided in example 1 of the present invention;

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

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

FIG. 6 is a cross-sectional view taken along line B-B of FIG. 3;

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

fig. 8 is a schematic view of the process for preparing the vascular stent of example 1.

Detailed Description

In the following, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the embodiments of the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.

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

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

In the embodiments of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," "fixed," and the like are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrated; the connection can be mechanical connection, electrical connection or communication; either directly or indirectly through intervening media, either internally or in any other relationship. Specific meanings of the above terms in the embodiments of the present invention can be understood by those of ordinary skill in the art according to specific situations.

In embodiments of the invention, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise the first and second features being in direct contact, or the first and second features being in contact, not directly, but via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly above and obliquely above the second feature, or simply meaning that the first feature is at a lesser level than the second feature.

The following disclosure provides many different embodiments or examples for implementing different configurations of embodiments of the invention. To simplify the disclosure of embodiments of the invention, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit embodiments of the invention. Furthermore, embodiments of the present invention may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

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

Example 1

Referring to fig. 1 to 8, in order to solve the problem that the conventional vascular stent cannot be well adapted to the requirement of a blood vessel with large deformation during exercise, such as a lower limb artery, the present embodiment provides a peripheral vascular stent, which includes a plurality of support units 1 and a membrane 2.

As shown in fig. 1 and 2, a plurality of support units 1 are sequentially arranged at intervals in the axial direction of the peripheral vascular stent. Each supporting unit 1 is formed by a wire in a closed ring shape, wherein the wire can be a monofilament formed by cutting and sizing a pipe or made in other forms, or can be a wire formed by twisting and weaving a plurality of wires, the material of the wire includes but is not limited to one or more of stainless steel, memory alloy, titanium alloy, tantalum alloy, cobalt-chromium alloy, biodegradable metal, biodegradable polymer, magnesium alloy and pure iron, and the supporting unit 1 formed by the wire can be a self-expanding supporting unit, or a supporting unit which needs to be expanded by a balloon and the like; preferably, the wire is made of nickel titanium alloy, which can realize self expansion, thereby providing better supporting force.

Each supporting unit 1 includes a plurality of peaks 11, valleys 12 arranged periodically in the circumferential direction with the axial line 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, and includes, but is not limited to, V-shape, U-shape, and the like. The axial lead of each supporting unit 1 is coincident with the axial lead of the peripheral vascular stent. In order to adapt to the structure that the artery of the lower limb is gradually tapered, the inner diameters of the plurality of supporting units 1 in the unfolding state gradually decrease 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 tapered is met, the application area of the vascular stent to the blood vessel is effectively improved, the chronic outward 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, a plurality of supporting units 1 are connected through a membrane 2 coated on the supporting units 1, and the flexibility of the membrane 2 is greater than that of the supporting units 1, so that the peripheral vascular stent adopts flexible connection, fatigue damage existing in a metal connecting structure is avoided, and the flexible structure has small irritation to endothelial cells in the processes of shortening, twisting, buckling, stretching and the like, so that vascular damage is reduced, and the requirement of the artery short contraction rate in various deformation states is met. The material of the membrane 2 includes but is not limited to polytetrafluoroethylene, block polyether amide, polyimide, and bioabsorbable medical material, and preferably the membrane 2 is polytetrafluoroethylene microporous membrane (ePTFE).

The film 2 may be a single-layer film or a double-layer film. When the membrane 2 is a single-layer membrane, the membrane 2 may be disposed inside the support unit 1 so as to minimize the influence of the peripheral vascular stent on the blood flow; the membrane 2 can also be arranged outside the supporting unit 1 so as to increase the contact area of the peripheral blood vessel stent and the blood vessel wall and reduce the damage of the peripheral blood vessel stent to the blood vessel wall. The membrane 2 is preferably a double-layer membrane, i.e. as shown in fig. 8, 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, so as to reduce the influence of the peripheral vascular stent on the blood flow and the damage of the peripheral vascular stent on the vascular wall.

In order to enable the peripheral blood vessel stent to be capable of better bending and twisting, a plurality of hollow areas 23 are formed on the film 2 between the wires of the same supporting unit 1 and/or between two adjacent supporting units 1, so that when the blood vessel stent is bent or twisted, the hollow areas 23 can provide an avoiding space. In the present embodiment, as shown in fig. 1 to 3, the hollowed-out regions 23 are opened on the film 2 between the wires of the same support unit 1 and between two adjacent support units 1. The supporting unit 1 is wrapped inside the film 2 without the supporting unit 1 protruding to the hollowed-out area 23 and without the supporting unit 1 directly contacting the vessel wall, and it is preferable that the area of the hollowed-out area 23 is set as large as possible.

Specifically, in two adjacent support units 1, one support unit 1 and the other support unit 1 are provided with a shift (peak offset) in the circumferential surface by a distance d of less than one-half period, preferably by a distance d of one-quarter period or less. In this embodiment, as shown in fig. 2, the offset distance d is a quarter of a period. Moreover, the cross section of the blood vessel stent shown in fig. 1 is taken as a circumferential surface, and when the circumferential surface is viewed downwards according to the orientation in fig. 1, the direction consistent with the rotation direction of the hour hand is taken as a clockwise direction; in the clockwise direction, each supporting unit 1 is circumferentially staggered from an adjacent supporting unit 1 by the same distance, and of course, a person skilled in the art can expect that the vascular stent obtained by the scheme of "in the counterclockwise direction, each supporting unit 1 is circumferentially staggered from an adjacent supporting unit 1 by the same distance" can obtain the same effect. In order to more clearly illustrate the staggered arrangement structure between two adjacent supporting units 1, as shown in fig. 2, when the peripheral vascular stent is cut along its axial direction and is unfolded into a plane, the next supporting unit 1 is always staggered to the left side by the same distance with respect to the previous supporting unit 1, so that the peaks and the peaks, the valley bottoms and the valley bottoms, and the peaks and the valley bottoms in the two adjacent supporting units are not aligned in the axial direction.

Specifically, as shown in fig. 2, each hollow area 23 in the present embodiment includes a first hollow portion 231 located in the peak 11 of each supporting unit 1, a second hollow portion 232 located in the valley 12 of each supporting unit 1, and a third hollow portion 233 located between two adjacent supporting units 1 and respectively communicated with the first hollow portion 231 and the second hollow portion 232. Moreover, each third hollow portion 233 is only communicated with the nearest first hollow portion 231 and the nearest second hollow portion 232, and the hollow areas 23 are independent and not communicated with each other, 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-out portion 231 is formed by enclosing a first wall 211 and a second wall 212 which are connected with each other at the upper end portions, the second hollow-out portion 232 is formed by enclosing a third wall 213 and a fourth wall 214 which are connected with each other at the lower end portions, and the third hollow-out portion 233 is formed by enclosing a fifth wall 215 which is connected with the lower end portions of the first wall 211 and the fourth wall 214 respectively and a sixth wall 216 which is connected with the lower end portions of the second wall 212 and the upper end portions of the third wall 213 respectively. The first wall 211 is parallel to the third wall 213, the second wall 212 is parallel to the fourth wall 214; the plurality of first walls 211 are parallel to each other, the plurality of second walls 212 are parallel to each other, and an included angle between the first walls 211 and the second walls 212 is an acute angle. When the peripheral stent is cut along its axial direction and expanded into a flat surface, as shown in fig. 2, the nearest two first walls 211 of two adjacent support units 1 are on a first straight line L, which is obliquely arranged, i.e., the first straight line L intersects with the length direction of the peripheral stent. The staggered arrangement of the supporting units 1 and the structural design of the hollow-out areas 23 enable the peripheral vascular stent to form a similar spiral structure, so that the peripheral vascular stent can better maintain the circular cross section in the states of bending, twisting and the like, and the vascular stent is prevented from collapsing; in addition, the peripheral vascular stent has better buckling, twisting, axial compression and tensile properties and better flexibility and radial support properties.

The preparation method of the peripheral vascular stent of this embodiment is:

respectively arranging an inner film 21 and an outer film 22 on the inner side and the outer side of a support unit 1, heating the inner film 21 and the outer film 22 to enable the support unit 1 to be covered between the inner film 21 and the outer film 22, thermally melting the inner film 21 and the outer film 22 outside the support unit 1 into a whole to form a film 2, and forming a plurality of hollow areas 23 on the film 2; or, a plurality of hollowed-out areas 23 are respectively arranged on the inner film 21 and the outer film 22, then 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 through heating, and the inner film 21 and the outer film 22 outside the supporting unit 1 are integrally hot-melted 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 interface between the inner membrane 21 and the outer membrane 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), that is topically administered with a therapeutic substance to achieve anti-angiogenesis and anti-endothelialization, thereby greatly increasing the area and manner of drug attachment.

Example 2 and example 3

The two embodiments are substantially the same as embodiment 1 except that: the film 2 of example 2 is a single-layer film disposed inside the supporting unit 1, and the film 2 of example 3 is a single-layer film disposed outside the supporting unit 1.

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

fixing the film 2 and the supporting unit 1 by means of hot melting, sewing and the like, and then forming a plurality of hollow areas 23 on the film 2; alternatively, a plurality of hollow areas 23 are formed in the film 2, and then the film 2 and the supporting unit 1 are fixed by heat fusion, sewing, or 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 stents of the above-described embodiments 1 to 3 are described with the peripheral vascular stents in the deployed state.

The peripheral blood vessel stent of the 3 embodiments is stored in the delivery mechanism and is in a contracted state in the process of delivering into the blood vessel, and when the peripheral blood vessel stent is delivered to the required part of the blood vessel, the peripheral blood vessel stent is automatically expanded to an expanded state to support the blood vessel after the delivery mechanism is withdrawn.

According to the intravascular stent, a plurality of mutually independent supporting units 1 are connected through the flexible membrane 2 provided with the hollow area 23, on the one hand, the flexible structure is connected with fatigue damage existing in a metal-free connecting structure, and the flexible structure has small irritation to endothelial cells in the shortening process, so that vascular damage is reduced, and the intravascular stent can adapt to the shortening rate of arteries in various deformation states; in a second aspect, the hollow area 23 enables the vascular stent of the present invention to adapt to the deformation of the peripheral blood vessel in a twisted state, and the stimulation of the flexible structure to endothelial cells is small in the twisting process, thereby reducing the damage of the blood vessel; in a third aspect, the blood vessel stent does not have the fish scale phenomenon and fatigue damage of a metal stent in a buckling state, and particularly can be bent under a small curvature radius without damaging the endothelium of a blood vessel in a peripheral blood vessel of a hip joint (such as a popliteal artery and the like); in a fourth aspect, the flexible connection is arranged, so that the intravascular stent has enough axial stretching rate, and can meet the requirement of axial stretching deformation of peripheral blood vessels; in the fifth aspect, the plurality of closed ring-shaped supporting units 1 arranged at intervals in the axial direction can provide enough radial supporting force, can bear the radial force and the crushing or pinching load of the peripheral blood vessel, and effectively support the artery to provide enough blood flow.

The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection 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 larger than the inner diameter in the contracted state; characterized in that said peripheral vascular stent comprises:

the supporting units (1) are sequentially arranged at intervals along the axial direction of the peripheral vascular stent, each supporting unit (1) is formed by a silk thread and is in a closed ring shape, each supporting 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 film (2) is covered on the plurality of supporting units (1), the flexibility of the film (2) is larger than that of the supporting units (1), a plurality of hollowed-out areas (23) are formed in the film (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 through the film (2) except the hollowed-out areas (23).

2. A peripheral vascular stent according to claim 1, wherein, in two adjacent strut elements (1), one strut element (1) and the other strut element (1) are arranged with a shift in the circumferential surface by a distance of less than one-half period.

3. The peripheral vascular stent of claim 2, wherein the offset distance is equal to or less than one-quarter of a period.

4. A peripheral vascular stent according to claim 2 or 3, wherein each of the strut units (1) is disposed offset from an adjacent one of the strut units (1) on the circumferential surface by the same distance in the clockwise direction.

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

6. Peripheral vascular stent according to claim 1, characterized in that the hollowed-out area (23) comprises:

a first hollowed-out portion (231) located inside a peak (11) of each of said supporting units (1),

A second hollowed-out portion (232) located inside a valley (12) of each support unit (1);

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

7. Peripheral vascular stent according to claim 6, characterized in that, in two adjacent strut elements (1), the valley bottom of one strut element (1) is connected with the nearest peak top of the other strut element (1) only by the strip-shaped membrane (2).

8. The peripheral vascular stent of claim 6, wherein the first hollow-out (231) is surrounded by a first wall (211) and a second wall (212) connected at their upper ends, and the second hollow-out (232) is surrounded by a third wall (213) and a fourth wall (214) connected at their lower ends,

the third hollow-out portion (233) is formed by a fifth wall (215) connected with the lower end of the first wall (211) and the upper end of the fourth wall (214) respectively and a sixth wall (216) connected with the lower end of the second wall (212) and the upper end of the third wall (213) respectively in a surrounding mode.

9. A peripheral vascular stent according to claim 8, characterized in that when the peripheral vascular stent is cut open in its axial direction and expanded into a planar shape, the nearest two first walls (211) of two adjacent support elements (1) are in a first straight line.

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

11. The peripheral vascular stent of claim 8, 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.

12. Peripheral vascular stent according to claim 1, characterized in that the membrane (2) is coated on the outside or/and inside of the support unit (1).

13. Peripheral vascular stent according to claim 1, characterized in that the membrane (2) comprises an inner membrane (21) inside the support unit (1) and an outer membrane (22) outside the support unit (1), the inner membrane (21) and the outer membrane (22) being fixedly connected, and the support unit (1) being wrapped between the inner membrane (21) and the outer membrane (22).

14. Peripheral vascular stent according to claim 13, characterized in that the inner membrane (21) and the outer membrane (22) in contact are hot-melted to form the membrane (2) in one piece.

15. A peripheral vascular stent according to claim 1, wherein the inner diameter of the peripheral vascular stent in the deployed state gradually decreases from one end to the other end.

16. Peripheral vascular stent according to claim 1, characterized in that the membrane (2) is coated with a drug.

17. Peripheral vascular stent according to claim 1, characterized in that the material of the support elements (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, preferably nitinol.

18. Peripheral vascular stent according to claim 1, characterized in that the material of the membrane (2) is one or more of polytetrafluoroethylene, block polyetheramide, polyimide, bioabsorbable medical material, preferably the membrane (2) is a polytetrafluoroethylene microporous membrane.

19. A method for preparing a peripheral vascular stent as claimed in claims 1 to 18, characterized in that a membrane (2) is fixed to the supporting element (1) and then a plurality of hollowed-out areas (23) are provided on the membrane (2).

20. A method for preparing a peripheral vascular stent as claimed in claims 1 to 18, characterized in that a plurality of hollowed-out areas (23) are provided on the membrane (2), and the membrane (2) is then fixed to the support element (1).

21. A method for preparing a peripheral vascular stent as claimed in claims 1 to 18, characterized in that an inner membrane (21) and an outer membrane (22) are respectively arranged on the inner side and the outer side of the supporting unit (1), the supporting unit (1) is wrapped 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 supporting unit (1) are heat-fused into a whole to form the membrane (2), and then a plurality of hollowed-out regions (23) are formed on the membrane (2).

22. A method for preparing a peripheral vascular stent according to claims 1 to 18, characterized in that a plurality of hollowed-out regions (23) are respectively formed on an inner membrane (21) and an outer membrane (22), then the inner membrane (21) and the outer membrane (22) are respectively arranged on the inner side and the outer side of a supporting unit (1), the hollowed-out regions (23) on the inner membrane (21) and the hollowed-out regions (23) on the outer membrane (22) are aligned, the supporting unit (1) is coated between the inner membrane (21) and the outer membrane (22) through heating, and the inner membrane (21) and the outer membrane (22) outside the supporting unit (1) are fused into a whole to form a membrane (2).