An external vascular stent and its preparation method

Abstract

The present invention relates to a peripheral vascular stent, which comprises a plurality of support units arranged at intervals and a membrane. Each support unit is formed by a silk thread and is a closed ring shape. Each support unit comprises a plurality of peaks and valleys that are centered on the axis of the peripheral vascular stent and are arranged periodically in the circumferential direction. Two adjacent peak tops form one cycle. The membrane is covered on the plurality of support units. The flexibility of the membrane is greater than that of the support unit. A plurality of hollowed-out areas are formed on the silk threads of the same support unit and / or on the membrane between two adjacent support units. Two adjacent support units are connected only through the membrane outside the hollowed-out areas. The vascular stent of the present invention can meet the mechanical property requirements under various deformation states of the lower limb artery, has appropriate radial supporting force and good flexibility, can well reduce the chronic outward expansion force in the vascular stent. The vascular stent of the present invention has little influence on blood flow, little damage to the inner wall of the blood vessel, and is not easy to cause secondary thrombosis formation.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical devices, and particularly relates to a peripheral vascular stent and a preparation method thereof. Background Art

[0002] Peripheral artery disease (PAD) caused by atherosclerosis is the third atherosclerotic cardiovascular disease after coronary heart disease and stroke. More than 300 million people worldwide suffer from PAD. The progression of this disease can cause claudication, rest pain, and amputation, seriously affecting the quality of life of patients. The main treatment methods for PAD include drugs, open surgery, and endovascular interventional treatment. With the development of interventional treatment for PAD, interventional treatment has been proven to be less invasive and more effective, and thus has become the main method for treating PAD. The two most common endovascular interventional methods are percutaneous transluminal balloon angioplasty and endovascular stent implantation. The disadvantage of the former is that the 1-year patency rate is only 28%-37%, while the latter significantly improves the short-term and long-term patency rates of diseased blood vessels.

[0003] Currently, the commonly used vascular stents are mainly divided into two categories: cutting type and braided type. Among them, the braided stent is mainly woven by metal wires, and the cutting type stent includes a plurality of closed rings made of metal and distributed at intervals along the axis, and a connecting piece made of metal for connecting adjacent two closed rings. Among them, the braided stent has certain flexibility and fatigue resistance, but the axial shortening rate is very high and the radial supporting force is relatively weak; while the cutting type stent has better radial supporting force and smaller axial shortening rate, but its flexibility is poor.

[0004] The lower limb arteries of the human body have unique physiological characteristics, pathological characteristics, kinematic characteristics, hydrodynamic characteristics, etc. However, the existing peripheral vascular stents cannot fully meet the unique requirements of the lower limb arteries. And after stent treatment for lower limb artery diseases, more than 40% of patients will have in-stent restenosis induced by chronic outward expansion force of the stent and low shear force in the stent. The peripheral vascular stent needs to overcome mechanical factors such as chronic outward expansion force and low shear force while ensuring a certain radial supporting force. However, the existing peripheral vascular stents cannot meet this requirement, which is the main reason for the high reintervention rate after peripheral vascular stent implantation surgery. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a vascular stent with sufficient radial supporting force and good flexibility, which can be applied to peripheral blood vessels, and a preparation method thereof.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] On the one hand, the present invention provides a peripheral vascular stent, which has a deployed state and a contracted state, and the inner diameter of the peripheral vascular stent in the deployed state is larger than that in the contracted state; the peripheral vascular stent includes:

[0008] Support units, which are a plurality of support units arranged at intervals along the axial direction of the peripheral vascular stent in sequence. Each support unit is formed by a silk thread and is a closed ring shape. Each support unit includes a plurality of peaks and valleys arranged periodically in the circumferential direction, and two adjacent peak tops are one cycle;

[0009] A membrane, which is covered on a plurality of the support units. The flexibility of the membrane is greater than that of the support units. A plurality of hollowed-out areas are formed on the membrane between the silk threads of the same support unit and / or between two adjacent support units. Two adjacent support units are connected only through the membrane outside the hollowed-out areas.

[0010] Since the lower limb arteries are different from other non-moving arterial vessels (such as coronary arteries, carotid arteries, aorta), they are in various deformed states under the long-term activities of the lower limbs. For example, the popliteal artery after squatting: the shortening rate is 13%-25%, the curvature radius after bending is 8-17 mm, and the twist degree is 14-26° / cm. These arterial deformations after movement will cause radial compression, torsion, flexion, axial tension and compression on the stent. However, the existing peripheral vascular stents are limited by the homogeneous design, so the flexibility and supporting force of the material cannot be taken into account at the same time, and thus cannot meet the characteristics of the above-mentioned lower limb arteries at the same time. The vascular stent of the present invention transcends the limitation of the homogeneous design. There is no metal connection between the multiple support units in the stent, and they are only connected through a flexible membrane with hollowed-out areas. On the one hand, the flexible structure connection has no fatigue damage of the metal connection structure, and the flexible structure has little irritation to endothelial cells during the shortening process, thereby reducing vascular damage and can adapt to the shortening rate of the artery in various deformed states; on the other hand, the vascular stent with the structure of the present invention can meet the deformation under the torsional state of the peripheral blood vessels, and the flexible structure has little irritation to endothelial cells during the torsion process, thereby reducing vascular damage; on the third hand, the vascular stent with the structure of the present invention has no "fish scale phenomenon" and fatigue damage of the metal stent in the flexed state. Especially in the peripheral blood vessels of the hip joint (such as the popliteal artery, etc.), the present invention can achieve bending with a small curvature radius without damaging the vascular endothelium; on the fourth hand, since the vascular stent with the structure of the present invention adopts a flexible connection, there is a sufficient axial elongation rate, which can meet the axial tensile deformation of the peripheral blood vessels; on the fifth hand, the vascular stent of the present invention adopts a plurality of closed ring-shaped support units arranged at intervals in the axial direction, so it can provide sufficient radial supporting force, can withstand the radial force and crushing or constriction load of the peripheral blood vessels, and effectively support the artery to provide sufficient blood flow.

[0011] According to some specific and preferred embodiments, in two adjacent support units, one support unit and the other support unit are staggeredly arranged on the circumferential surface, and the staggering distance is less than half a period, so that the vascular stent has better flexion, torsion, axial compression and tensile properties.

[0012] Further preferably, the staggering distance is less than or equal to one-quarter of a period.

[0013] Further preferably, in the clockwise direction, each support unit is staggeredly arranged with an adjacent support unit on the circumferential surface and the staggering distances are the same, so that the support units can generally form a structure similar to a helix, so that when the vascular stent is in a bent, twisted state, etc., the cross-section of the vascular stent can be better maintained in a circular shape, avoiding the collapse of the vascular stent.

[0014] It should be noted that the clockwise direction in the text is only for convenience of description and does not constitute a limitation on the protection scope of the present application. When in the counterclockwise direction, the same technical effects can be achieved and it is also within the protection scope of the present application.

[0015] According to some specific and preferred embodiments, the axis line of each support unit coincides with the axis line of the outer peripheral vascular stent. In the present application, the meaning that the axis line of each support unit coincides with the axis line of the outer peripheral vascular stent is: when the outer peripheral vascular stent includes a main stent and a branch stent connected to the main stent, the axis line of the support unit located in the main stent part coincides with the axis line of the main stent, and the axis line of the support unit located in the branch stent part coincides with the axis line of the branch stent; when the outer peripheral vascular stent has no branches, the axis line of each support unit coincides with the axis line of the outer peripheral vascular stent.

[0016] According to some specific and preferred embodiments, the hollowed-out area includes

[0017] a first hollowed-out part located within the peak of each support unit,

[0018] a second hollowed-out part located within the valley of each support unit,

[0019] a plurality of third hollowed-out parts located between two adjacent support units and respectively communicating with the first hollowed-out part and the second hollowed-out part; so that the vascular stent has better flexibility and can better flex and twist along with the blood vessel.

[0020] In some embodiments, some of the plurality of third hollowed-out parts between two adjacent support units can communicate with each other, but cannot all communicate to cause the separation of the two adjacent support units without a membrane connection.

[0021] Further, each of the third hollow portions is only connected to the nearest first hollow portion and second hollow portion, so that there are more connection positions between adjacent support units, and thus the connection between adjacent support units is more firm.

[0022] According to some specific and preferred embodiments, between two adjacent support units, the bottom of one support unit and the nearest peak of the other support unit are only connected by a strip-shaped film.

[0023] According to some more specific and preferred embodiments, the first hollow portion is surrounded by a first wall and a second wall connected at the upper end, and the second hollow portion is surrounded by a third wall and a fourth wall connected at the lower end.

[0024] The third hollow portion is surrounded by a fifth wall connected to the lower end of the first wall and the upper end of the fourth wall, and a sixth wall connected to the lower end of the second wall and the upper end of the third wall.

[0025] Further preferably, the first hollow portion and the second hollow portion are as large as possible, and only need to ensure that the film wraps the support unit. In addition, since two adjacent support units are staggeredly arranged, the first hollow portion and the second hollow portion are also staggeredly arranged, so that the hollow area forms two staggered and inverted triangles, thereby making the vascular stent have better flexibility and being able to better flex and twist along with the blood vessel.

[0026] Further preferably, when the peripheral vascular stent is axially cut and unfolded into a planar shape, the nearest two first walls in two adjacent support units are on a first straight line, and the first straight line is inclined, so that the vascular stent can form a similar spiral structure, and thus the vascular stent can better maintain a circular cross-section in a bent or twisted state and avoid collapse of the vascular stent.

[0027] Further preferably, the included angle between the first wall and the second wall is an acute angle.

[0028] Further preferably, the first wall and the third wall are parallel, the second wall and the fourth wall are parallel, and multiple second walls are parallel.

[0029] According to some specific and preferred embodiments, the membrane is coated on the outer side and / or the inner side of the support unit, so that the vascular stent of the present invention has less influence on the blood flow in the blood vessel, thereby reducing the probability of blood flow disorder and abnormal shear stress / shear rate after stent implantation, and thus reducing the probability of a series of inflammations and blood vessel injuries in the blood vessel. And the present invention effectively increases the adhesion area between the vascular stent and the blood vessel by covering a relatively soft membrane outside the support unit, thereby increasing the pulling-out force of the vascular stent on the blood vessel, and thus further reducing the chronic outward expansion force of the vascular stent while maintaining sufficient radial support force and good flexibility. Moreover, on the one hand, the film-covered design closes the dissection break of the peripheral blood vessel to a certain extent; on the other hand, a hollowed-out area is provided on the film. Compared with the fully film-covered design, it can avoid completely covering the branch blood vessels, so it is applicable to peripheral blood vessels with more branch blood vessels, such as the popliteal artery.

[0030] According to some specific and preferred embodiments, the membrane includes an inner membrane located on the inner side of the support unit and an outer membrane located on the outer side of the support unit. The inner membrane and the outer membrane are fixedly connected, and the support unit is covered between the inner membrane and the outer membrane.

[0031] Furthermore, the contacting inner membrane and outer membrane are melted together to form the membrane.

[0032] According to some preferred embodiments, the inner diameter of the peripheral vascular stent gradually decreases from one end to the other end in the deployed state, so as to meet the physiological characteristics of the conical decrease in the diameter of the lower limb arteries of the human body, effectively increasing the adhesion area of the vascular stent to the blood vessel and reducing the chronic outward expansion force of the stent, thereby avoiding the probability of in-stent restenosis.

[0033] According to some specific and preferred embodiments, the membrane is coated with a drug, thus greatly increasing the drug attachment area and providing more drug attachment methods. The drugs that can be coated on the surface of the membrane include, but are not limited to, drug-polymer carriers or active agents (such as bioactive agents), and local administration of therapeutic substances can achieve anti-angiogenesis and anti-endothelialization.

[0034] According to some specific and preferred embodiments, the material of the support unit is one or more of stainless steel, shape memory alloy, titanium alloy, tantalum alloy, cobalt-chromium alloy, bioabsorbable metal, bioabsorbable polymer, magnesium alloy, pure iron, and preferably nitinol.

[0035] According to some specific and preferred embodiments, the material of the membrane is one or more of polytetrafluoroethylene, block polyether amide, polyimide, bioabsorbable medical materials. Preferably, the membrane is a polytetrafluoroethylene microporous membrane.

[0036] The peripheral vascular stent of the present invention is applicable to endovascular treatment of various peripheral blood vessels, including the superficial femoral artery, iliac artery, carotid artery, radial artery, lower extremity artery, etc. Among them, the peripheral vascular stent of the present invention is particularly applicable to blood vessels that will undergo large deformations.

[0037] The support unit in the present invention can be a self-expanding or balloon-expandable support unit.

[0038] The second aspect of the present invention is to provide a method for preparing the peripheral vascular stent described above, fixing the membrane to the support unit, and then opening a plurality of hollowed areas on the membrane.

[0039] The third aspect of the present invention is to provide a method for preparing the peripheral vascular stent described above, opening a plurality of hollowed areas on the membrane, and then fixing the membrane to the support unit.

[0040] The fourth aspect of the present invention is to provide a method for preparing the peripheral vascular stent described above, respectively arranging the inner membrane and the outer membrane on the inner side and the outer side of the support unit, heating the inner membrane and the outer membrane so that the support unit is covered between the inner membrane and the outer membrane, and the inner membrane and the outer membrane outside the support unit are melted together to form a membrane, and then opening a plurality of hollowed areas on the membrane.

[0041] The fifth aspect of the present invention is to provide a method for preparing the peripheral vascular stent described above, respectively opening a plurality of hollowed areas on the inner membrane and the outer membrane, then respectively arranging the inner membrane and the outer membrane on the inner side and the outer side of the support unit, and aligning the hollowed areas on the inner membrane and the hollowed areas on the outer membrane, and heating so that the support unit is covered between the inner membrane and the outer membrane, and the inner membrane and the outer membrane outside the support unit are melted together to form a membrane.

[0042] Due to the application of the above technical solutions, the present invention has the following advantages compared with the prior art:

[0043] The peripheral vascular stent of the present invention can meet the mechanical performance requirements under various deformation states of the peripheral blood vessels. The peripheral vascular stent of the present invention can balance appropriate radial support force and good flexibility, can well reduce the chronic outward expansion force in the peripheral vascular stent, reduce the incidence of restenosis in the peripheral vascular stent, and moreover, the peripheral vascular stent of the present invention has little influence on blood flow, little damage to the blood vessel inner wall, and is not easy to cause secondary thrombus formation. Description of the Drawings

[0044] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0045] Figure 1 Stereogram of the vascular stent provided in Embodiment 1 of the present invention;

[0046] Figure 2 Structural schematic diagram of the vascular stent provided in Embodiment 1 of the present invention axially cut and unfolded into a plane;

[0047] Figure 3 Partial enlarged view of the vascular stent provided in Embodiment 1 of the present invention;

[0048] Figure 4 For Figure 3 A - A sectional view;

[0049] Figure 5 For Figure 4 Partial enlarged view;

[0050] Figure 6 For Figure 3 B - B sectional view;

[0051] Figure 7 For Figure 6 Partial enlarged view;

[0052] Figure 8 Schematic diagram during the preparation process of the vascular stent in Embodiment 1. Detailed implementation manners

[0053] In the following, only some exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the embodiments of the present invention. Therefore, the drawings and descriptions are considered to be exemplary in nature rather than restrictive.

[0054] In the description of the embodiments of the present invention, it should be understood that the orientation or positional relationships indicated by terms such as "length", "inner", "upper", etc. are based on the Figure 1 orientation or positional relationships shown in the drawings. It is only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the embodiments of the present invention.

[0055] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present invention, the meaning of "a plurality of" is two or more, unless otherwise specifically defined.

[0056] In the embodiments of the present invention, unless otherwise clearly defined and limited, terms such as "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or a communication connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0057] In the embodiments of the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature in terms of horizontal height. The first feature being "under", "beneath" and "underneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature is at a lower level than the second feature in terms of horizontal height.

[0058] The following disclosure provides many different embodiments or examples for implementing different structures of the embodiments of the present invention. To simplify the disclosure of the embodiments of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the embodiments of the present invention. In addition, the embodiments of the present invention may repeat reference numerals and / or reference letters in different examples. This repetition is for the purpose of simplification and clarity and does not itself indicate the relationship between the various embodiments and / or settings discussed.

[0059] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0060] Embodiment 1

[0061] Please refer to Figures 1 - 8 , in order to solve the problem that existing vascular stents cannot well adapt to blood vessels with large deformations during movement, such as the requirements of the lower limb arteries, this embodiment provides a peripheral vascular stent, which includes a plurality of support units 1 and a membrane 2.

[0062] As Figure 1 and Figure 2 shown, a plurality of support units 1 are sequentially arranged at intervals along the axial direction of the peripheral vascular stent. Each support unit 1 is formed by a silk thread and is a closed ring shape. The silk thread can be a single wire formed by cutting and shaping a pipe material or other forms, or can be a single wire formed by twisting and braiding multiple silk threads. The material of the silk thread includes but is not limited to one or more of stainless steel, shape memory alloy, titanium alloy, tantalum alloy, cobalt-chromium alloy, bioabsorbable metal, bioabsorbable polymer, magnesium alloy, pure iron. The support unit 1 formed by the silk thread can be a self-expanding support unit or a support unit that needs to be expanded by means of a balloon, etc.; preferably, the silk thread is made of nitinol alloy, which can achieve self-expansion and thus can provide better supporting force.

[0063] Each support unit 1 includes a plurality of peaks 11 and valleys 12 that are centered on the axis of the peripheral vascular stent and are periodically arranged in the circumferential direction, and two adjacent peak tops are one cycle. Among them, the shape of the silk thread forming one cycle only needs to be a shape with peaks and valleys, including but not limited to V-shaped, U-shaped, etc. The axis of each support unit 1 coincides with the axis of the peripheral vascular stent. In order to adapt to the gradually tapered structure of the lower limb artery, the inner diameter of the plurality of support units 1 gradually decreases from one end to the other end in the deployed state, so as to meet the physiological characteristics of the decreasing diameter of the human lower limb artery in a tapered shape, effectively increase the apposition area of the vascular stent to the blood vessel, and reduce the chronic outward expansion force of the stent, thereby significantly reducing the occurrence probability of restenosis in the stent.

[0064] As Figure 1 and Figure 2 shown, the plurality of support units 1 are connected by a membrane 2 covering the support unit 1. The flexibility of the membrane 2 is greater than that of the support unit 1, so that the peripheral vascular stent adopts a flexible connection, there is no fatigue damage caused by a metal connection structure, and the flexible structure has little irritation to endothelial cells during processes such as shortening, torsion, flexion, and stretching, thereby reducing blood vessel damage and can meet the shortening rate of the artery in various deformed states. The material of the membrane 2 includes but is not limited to polytetrafluoroethylene, block polyether amide, polyimide, bioabsorbable medical materials. Preferably, the membrane 2 is a polytetrafluoroethylene microporous membrane (ePTFE).

[0065] Among them, the membrane 2 can 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 inside the support unit 1 to minimize the influence of the peripheral vascular stent on blood flow as much as possible; the membrane 2 can also be arranged outside the support unit 1 to increase the contact area between the peripheral vascular stent and the blood vessel wall and reduce the damage of the peripheral vascular stent to the blood vessel wall. Preferably, the membrane 2 is a double-layer membrane, that is, as Figure 8As shown, 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, which can not only reduce the influence of the peripheral vascular stent on blood flow but also reduce the damage of the peripheral vascular stent to the blood vessel wall.

[0066] In order to enable the peripheral vascular stent to bend and twist better, a plurality of hollowed-out areas 23 are provided on the membrane 2 between the filaments of the same support unit 1 and / or between two adjacent support units 1. Thus, when the vascular stent bends or twists, the hollowed-out areas 23 can provide a clearance space. In this embodiment, Figures 1 to 3 As shown, the hollowed-out areas 23 are provided on the membrane 2 between the filaments of the same support unit 1 and between two adjacent support units 1. The support unit 1 is covered inside the membrane 2, and no support unit 1 extends into the hollowed-out areas 23 and the support unit 1 does not directly contact the blood vessel wall. Preferably, the area of the hollowed-out areas 23 is set as large as possible.

[0067] Specifically, in two adjacent support units 1, one support unit 1 and the other support unit 1 are arranged staggeredly (staggered peaks) on the circumferential surface, and the staggering distance d is less than half a period, and preferably the staggering distance d is less than or equal to a quarter of a period. In this embodiment, Figure 2 As shown, the staggering distance d is a quarter of a period. And, taking the cross-section of the vascular stent as shown in Figure 1 as the circumferential surface, and observing this circumferential surface downward according to the orientation in Figure 1 , the clockwise direction is the direction consistent with the clockwise rotation of the hour hand; in the clockwise direction, each support unit 1 is arranged staggeredly on the circumferential surface with an adjacent support unit 1 and the staggering distance is the same. Of course, those skilled in the art can expect that the vascular stent obtained by the solution of "in the counterclockwise direction, each support unit 1 is arranged staggeredly on the circumferential surface with an adjacent support unit 1 and the staggering distance is the same" can achieve the same effect. To more clearly illustrate the staggered structure between two adjacent support units 1, as Figure 2 shown, when the peripheral vascular stent is axially cut and unfolded into a plane, the next support unit 1 is always staggered to the left by the same distance relative to the previous support unit 1, so that the peaks and peaks, valleys and valleys, peaks and valleys in the axial direction of two adjacent support units are not aligned.

[0068] Specifically, as Figure 2As shown, each hollowed-out area 23 in this embodiment includes a first hollowed-out portion 231 located within the peak 11 of each support unit 1, a second hollowed-out portion 232 located within the valley 12 of each support unit 1, and a third hollowed-out portion 233 located between two adjacent support units 1 and communicating with the first hollowed-out portion 231 and the second hollowed-out portion 232 respectively. Moreover, each third hollowed-out portion 233 communicates only with the nearest first hollowed-out portion 231 and second hollowed-out portion 232, and the hollowed-out areas 23 are independent of each other and not connected. Such that between two adjacent support units 1, the bottom of one support unit 1 is connected to the nearest peak of the other support unit 1 only through the strip-shaped film 2.

[0069] Furthermore, the first hollowed-out portion 231 is formed by enclosing with a first wall 211 and a second wall 212 whose upper ends are connected; the second hollowed-out portion 232 is formed by enclosing with a third wall 213 and a fourth wall 214 whose lower ends are connected; the third hollowed-out portion 233 is formed by enclosing with a fifth wall 215 connected to the lower end of the first wall 211 and the upper end of the fourth wall 214, and a sixth wall 216 connected to the lower end of the second wall 212 and the upper end of the third wall 213. The first wall 211 and the third wall 213 are parallel, and the second wall 212 and the fourth wall 214 are parallel; multiple first walls 211 are parallel to each other, multiple second walls 212 are parallel to each other, and the included angle between the first wall 211 and the second wall 212 is an acute angle. As Figure 2 shown, when the peripheral vascular stent is axially cut and unfolded into a plane, the nearest two first walls 211 in two adjacent support units 1 are on the first straight line L, and the first straight line L is inclined, that is, the first straight line L intersects with the length direction of the peripheral vascular stent. The staggered arrangement of the support units 1 and the structural design of the hollowed-out area 23 enable the peripheral vascular stent to form a similar spiral structure, so that when the peripheral vascular stent is in a bent, twisted and other states, it can better maintain a circular cross-section and avoid the collapse of the vascular stent; moreover, this structural design enables the peripheral vascular stent to have better flexion, torsion, axial compression and tensile properties while having better flexibility and radial support performance.

[0070] The preparation method of the peripheral vascular stent in this embodiment is as follows:

[0071] The inner membrane 21 and the outer membrane 22 are respectively arranged inside and outside the support unit 1. By heating the inner membrane 21 and the outer membrane 22, the support unit 1 is wrapped between the inner membrane 21 and the outer membrane 22. The inner membrane 21 and the outer membrane 22 outside the support unit 1 are melted together to form the membrane 2, and then a plurality of hollow areas 23 are formed on the membrane 2; alternatively, a plurality of hollow areas 23 are respectively formed on the inner membrane 21 and the outer membrane 22, and then the inner membrane 21 and the outer membrane 22 are respectively arranged inside and outside the support unit 1, and the hollow areas 23 on the inner membrane 21 and the hollow areas 23 on the outer membrane 22 are aligned. By heating, the support unit 1 is wrapped between the inner membrane 21 and the outer membrane 22, and the inner membrane 21 and the outer membrane 22 outside the support unit 1 are melted together to form the membrane 2.

[0072] In this embodiment, the outer surface of the inner membrane 21, the outer surface of the outer membrane 22, and the surface between the inner membrane 21 and the outer membrane 22 can be selectively coated with drugs, thereby greatly increasing the drug attachment area and method. The coated drugs include but are not limited to drug polymer carriers or active agents (such as bioactive agents), and local administration of therapeutic substances is used to achieve anti-angiogenesis and anti-endothelialization.

[0073] Embodiment 2 and Embodiment 3

[0074] These two embodiments are basically the same as Embodiment 1, except that: the membrane 2 in Embodiment 2 is a single-layer membrane arranged inside the support unit 1, and the membrane 2 in Embodiment 3 is a single-layer membrane arranged outside the support unit 1.

[0075] The preparation method of the peripheral vascular stent in these two embodiments is as follows:

[0076] The membrane 2 and the support unit 1 are fixed by means of hot melting, sewing, etc., and then a plurality of hollow areas 23 are formed on the membrane 2; or, a plurality of hollow areas 23 are formed on the membrane 2, and then the membrane 2 and the support unit 1 are fixed by means of hot melting, sewing, etc.

[0077] The peripheral vascular stent has a deployed state and a contracted state, and the inner diameter in the deployed state is larger than that in the contracted state. The structures of the peripheral vascular stents in the above Embodiments 1 to 3 are described when the peripheral vascular stent is in the deployed state.

[0078] During the process of the peripheral vascular stent in these 3 embodiments being delivered into the blood vessel, it is stored in the delivery mechanism and in the contracted state. When it is delivered to the required part of the blood vessel, after withdrawing the delivery mechanism, the peripheral vascular stent automatically expands to the deployed state to support the blood vessel.

[0079] A plurality of mutually independent support units 1 in the vascular stent of the present invention are connected by a flexible membrane 2 provided with a hollowed-out area 23. In the first aspect, the flexible structure connection has no fatigue damage of the metal connection structure, and the flexible structure has little irritation to endothelial cells during the shortening process, thereby reducing vascular damage and can adapt to the shortening rate of arteries in various deformed states; in the second aspect, the setting of the hollowed-out area 23 enables the vascular stent of the present invention to adapt to the deformation under the torsional state of peripheral blood vessels, and the flexible structure has little irritation to endothelial cells during the torsion process, thereby reducing vascular damage; in the third aspect, the vascular stent of the present invention has no "fish scale phenomenon" and fatigue damage of the metal stent in the flexed state. Especially in the peripheral blood vessels of the hip joint (such as the popliteal artery, etc.), the present invention can achieve bending with a small radius of curvature without damaging the vascular endothelium; in the fourth aspect, the setting of the flexible connection enables the vascular stent of the present invention to have a sufficient axial elongation rate to meet the axial tensile deformation of peripheral blood vessels; in the fifth aspect, a plurality of closed annular support units 1 arranged at intervals along the axis can provide sufficient radial support force, can withstand the radial force, crushing or constriction load of peripheral blood vessels, and effectively support the artery to provide sufficient blood flow.

[0080] The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. An extracorporeal vascular stent, which has a deployed state and a contracted state, and the inner diameter of the extracorporeal vascular stent in the deployed state is larger than its inner diameter in the contracted state; characterized in that, The peripheral vascular stent includes: Support units (1), a plurality of the support units (1) are arranged at intervals in sequence along the axial direction of the peripheral vascular stent, each of the support units (1) is formed by a silk thread and is a closed ring shape, each of the support units (1) includes a plurality of peaks (11) and valleys (12) arranged periodically in the circumferential direction, and two adjacent peak tops are one period; A membrane (2), the membrane (2) is covered on a plurality of the support units (1), the flexibility of the membrane (2) is greater than that of the support unit (1), a plurality of hollowed - out areas (23) are formed on the membrane (2) between the silk threads of the same support unit (1) and / or between two adjacent support units (1), and two adjacent support units (1) are connected only through the membrane (2) outside the hollowed - out areas (23), without metal connection; Among two adjacent support units (1), one support unit (1) and the other support unit (1) are arranged staggeredly on the circumferential surface, and the staggering distance is less than half of a period; The hollowed - out area (23) includes: A first hollowed - out part (231) located within the peak (11) of each support unit (1), A second hollowed - out part (232) located within the valley (12) of each support unit (1); A plurality of third hollowed - out parts (233) located between two adjacent support units (1) and respectively communicating with the first hollowed - out part (231) and the second hollowed - out part (232).

2. The peripheral vascular stent according to claim 1, wherein The staggering distance is less than or equal to one - quarter of a period.

3. The peripheral vascular stent according to claim 2, wherein In the clockwise direction, each support unit (1) is arranged staggeredly with an adjacent support unit (1) on the circumferential surface and the staggering distance is the same.

4. The peripheral vascular stent according to claim 1, characterized in that, The axis line of each support unit (1) coincides with the axis line of the peripheral vascular stent.

5. The peripheral vascular stent according to claim 1, wherein Among two adjacent support units (1), only a strip - shaped membrane (2) is used to connect the bottom of one support unit (1) and the nearest peak top of the other support unit (1).

6. The peripheral vascular stent according to claim 1, wherein The first hollowed - out part (231) is surrounded by a first wall (211) and a second wall (212) whose upper ends are connected, and the second hollowed - out part (232) is surrounded by a third wall (213) and a fourth wall (214) whose lower ends are connected. The third hollowed - out part (233) is surrounded by a fifth wall (215) respectively connected to the lower end of the first wall (211) and the upper end of the fourth wall (214), and a sixth wall (216) respectively connected to the lower end of the second wall (212) and the upper end of the third wall (213).

7. The peripheral vascular stent according to claim 6, characterized in that, When the peripheral vascular stent is axially cut and unfolded into a planar shape, the nearest two first walls (211) among two adjacent support units (1) are on a first straight line.

8. The peripheral vascular stent according to claim 6, wherein The included angle between the first wall (211) and the second wall (212) is an acute angle.

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

10. The peripheral vascular stent according to claim 1, characterized in that, The membrane (2) is coated on the outer side and / or the inner side of the support unit (1).

11. The peripheral vascular stent according to claim 1, characterized in that, 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). 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. The peripheral vascular stent according to claim 11, characterized in that, The in-contact inner membrane (21) and outer membrane (22) are melted together by heat to form the membrane (2).

13. The peripheral vascular stent according to claim 1, characterized in that, The inner diameter of the peripheral vascular stent gradually decreases from one end to the other end in the deployed state.

14. The peripheral vascular stent according to claim 1, characterized in that, The membrane (2) is coated with a drug.

15. The peripheral vascular stent according to claim 1, characterized in that, The material of the support unit (1) is one or more of stainless steel, shape memory alloy, titanium alloy, tantalum alloy, cobalt-chromium alloy, bio-degradable metal, bio-degradable polymer, magnesium alloy, and pure iron.

16. The 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 material of the membrane (2) is one or more of polytetrafluoroethylene, block polyether amide, polyimide, and bioabsorbable medical materials.

18. The peripheral vascular stent according to claim 1, characterized in that, The membrane (2) is a polytetrafluoroethylene microporous membrane.

19. A method for preparing a peripheral vascular stent according to any one of claims 1 to 18, characterized in that, Fix the membrane (2) to the support unit (1), and then form a plurality of hollowed areas (23) on the membrane (2).

20. A method for preparing a peripheral vascular stent according to any one of claims 1 to 18, characterized in that, Form a plurality of hollowed areas (23) on the membrane (2), and then fix the membrane (2) to the support unit (1).

21. A method for preparing a peripheral vascular stent according to any one of claims 1 to 18, characterized in that, Dispose the inner membrane (21) and the outer membrane (22) on the inner side and the outer side of the support unit (1) respectively. By heating the inner membrane (21) and the outer membrane (22), the support unit (1) is coated between the inner membrane (21) and the outer membrane (22). The inner membrane (21) and the outer membrane (22) outside the support unit (1) are melted together by heat to form the membrane (2), and then form a plurality of hollowed areas (23) on the membrane (2).

22. A method for preparing a peripheral vascular stent according to any one of claims 1 to 18, characterized in that, Form a plurality of hollowed areas (23) on the inner membrane (21) and the outer membrane (22) respectively. Then dispose the inner membrane (21) and the outer membrane (22) on the inner side and the outer side of the support unit (1) respectively, and align the hollowed areas (23) on the inner membrane (21) with the hollowed areas (23) on the outer membrane (22). By heating, the support unit (1) is coated between the inner membrane (21) and the outer membrane (22). The inner membrane (21) and the outer membrane (22) outside the support unit (1) are melted together by heat to form the membrane (2).

Images