A lumen stent and its preparation method and application

Abstract

The application discloses a kind of luminal stent and its preparation method and application, and the stent includes front end, the front end constitutes the one end pipe body of stent, front end includes first part and second part, the first part and the second part are arranged along the circumference of the stent and are connected;Middle part, the middle part constitutes the pipe body of the stent, wherein, the part pipe body of the middle part is adjacent and is connected with the first part of the front end;And first transition, the first transition is between the second part of the front end and the middle part, and the second part of the front end is connected with the middle part by the first transition.The stent of the application has different performance regions in its axial or circumferential direction, meets the special luminal application requirements, and is particularly suitable for luminal stent for treating iliac vein stenosis disease.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices for interventional procedures, in particular to an implantable intraluminal stent, and its preparation method and application. BACKGROUND

[0002] Stents are used to be implanted in the diseased segment of a lumen to support the stenosis or occlusion segment of the lumen and keep the lumen unobstructed. Typical stents are used to be implanted in the diseased segment of a blood vessel to support the stenosis or occlusion segment of the blood vessel, reduce the elastic recoil and reshaping of the blood vessel, and keep the blood flow unobstructed. Due to the physiological structure differences of blood vessels in different parts of the human body, special stents have been developed for different blood vessel diseases, and in general, stents for different indications cannot be used interchangeably.

[0003] The most common clinical venous stenosis diseases are iliac vein stenosis, which is caused by Cockett syndrome, postthrombotic syndrome (PTS), tumor compression, etc. The most common one is Cockett syndrome, also known as iliac vein compression syndrome. It is caused by the long-term compression of the left common iliac vein by the right iliac artery from the front and the fifth lumbar vertebra from the back, and the mechanical action caused by the pulsation, resulting in intimal hyperplasia, intraluminal adhesion, and stenosis or occlusion of the left common iliac vein, which leads to obstruction of the iliac vein, deep vein thrombosis, varicose veins, pigmentation, and lower extremity erosion. Implanting a stent in the diseased segment of the left common iliac vein through interventional surgery is the preferred treatment for Cockett syndrome.

[0004] Compared with the general stenosis of venous or arterial blood vessels caused by deposition of embolic material or intimal hyperplasia, the stenosis of the left common iliac vein in Cockett syndrome is mainly caused by physical compression of the artery and the fifth lumbar vertebra and the resulting intravascular fibrosis. Therefore, the stent needs to have stronger support performance at the corresponding compression site, and at the same time, the iliac vein is close to the pelvic bone and has a more curved physiological structure, so the corresponding segment of the stent needs to have excellent flexibility.

[0005] Metallic tube cut stents with helical patterns have been proposed, which have excellent torsional flexibility and bending performance. For example, Chinese published patents CN108670511A, CN108371572A, CN103784222A, CN203662949U, CN103313681A, CN106137479A, US20040044401A, US20130338759A, and PCT published patent WO2012018844A, etc. respectively disclose various stents with single helix support structure.

[0006] In addition, Chinese patent CN108348345A, as well as the applicant's prior applications Chinese patents CN109662819A and CN113413256A, all disclose stents with double helix support structure.

[0007] In the above designs, the helix support structure of the stent usually needs to be closed in the end part in the circumferential direction.

[0008] For example, CN108348345A proposes that the helix body of the stent is closed and connected with an end ring through a plurality of axial connecting struts arranged in the circumferential direction and having different lengths, and the transition zone between the end ring and the helix body is divided into a plurality of hollow zones of different sizes in the circumferential direction by the axial connecting struts, wherein the helix body can be single helix or double helix.

[0009] In another example, US20040044401A1 proposes that the helix body of the stent is closed and connected with an end ring through a transition zone which is generally trapezoidal in the circumferential direction, and the transition zone is composed of a single winding of undulations, and the helix body is single helix.

[0010] The applicant's prior Chinese patent CN109662819A discloses a self-expanding stent which contains both single helix body and double helix body, and the double helix body is first closed into a single helix body in the circumferential direction to the side of the stent, and then the single helix body is closed and connected with an end ring through a transition zone, and the transition zone has the same manner as the transition zone of US20040044401A1, but the end ring is an inclined ring.

[0011] The stents disclosed in the foregoing patents have a transition zone which is an independent annular structure or a plurality of axial rod structures distributed in the annular direction, and connects the stent body and the stent end part located on both sides of the transition zone. Although the structures may be different, the transition zone gradually changes in shape or size in the circumferential direction to bridge the shape difference of the adjacent surfaces of the stent body and the stent end part.

[0012] However, the existing transition zone design may be disadvantageous in some cases. On the one hand, the gradual change in shape or size of the annular transition zone in the circumferential direction easily leads to a gradual change in the expansion capability of the transition zone in the circumferential direction when the stent is radially expanded. When the stent changes from the compressed state to the expanded state, different parts of the transition zone have different radial expansion capabilities, which easily leads to uneven expansion, thereby affecting the stent's adhesion to the blood vessel wall and support for the blood vessel lumen. On the other hand, the length of the stent acting on the treatment zone in the blood vessel is limited, and the transition zone to some extent can be regarded as limiting the optimal design of the stent performance. Compared with the end or middle part of the main body of the stent, the transition zone may be difficult to achieve the same degree of flexibility, support, torsion and other performances. In addition, due to the different pathophysiology and anatomical locations of arterial stenosis and iliac vein obstruction, an ideal vein stent must provide flexibility, radial support force, precise release and other characteristics under the pathophysiological conditions of vein disease. The annular design of the transition zone of the stent in the prior art generally provides a gradual performance transition from the end of the stent to the middle part, which may not be sufficient to meet the clinical needs of special lumens such as iliac veins. SUMMARY

[0013] One aspect of the present application is to provide a lumen stent having different performance regions in the axial or circumferential direction to meet the application requirements of special lumens.

[0014] Another aspect of the present application is to provide an application of the aforementioned lumen stent, i.e., to provide a lumen stent suitable for the treatment of iliac vein stenosis.

[0015] Still another aspect of the present application is to provide a preparation method of the aforementioned lumen stent.

[0016] In one embodiment of the present application, the lumen stent is a hollow tube, and the lumen stent comprises:

[0017] a front end portion constituting an end tube of the stent, the front end portion comprising a first portion and a second portion, the first portion and the second portion being arranged along the circumferential direction of the stent and being connected;

[0018] a middle portion constituting a section of the tube of the stent, wherein a part of the middle portion is adjacent to and connected with the first portion of the front end portion; and

[0019] a first transition portion between the second portion of the front end portion and the middle portion, and the second portion of the front end portion is connected with the middle portion through the first transition portion.

[0020] A stent for implanting in a diseased section of a lumen, typically a hollow tube, to fit the diseased section of the lumen, to provide support to the lumen to form a flow passage, and to maintain patency of the lumen. The tube of the stent typically needs to be provided with openings or apertures to provide the stent with the ability to transform from a compressed configuration for delivery through a catheter to an expanded configuration for implanting and supporting the diseased lumen. The distribution or shape of the openings or apertures in the tube can be varied to provide different properties of radial support or flexibility at different locations of the stent.

[0021] It can be appreciated that the tube of the stent can be obtained by etching a tube to remove excess material, and the pattern of the stent is formed by the distribution of the openings on the circumference of the tube, or the stent can be obtained by combining a plurality of rods and fixing them by welding or the like, and the pattern of the stent is formed by the apertures enclosed by the rods on the circumference of the tube. Different patterns of the stent provide different properties of torsion, support, bending, etc. of the stent, which are well known to those skilled in the art. The preparation method of the stent is not limited to the above, for example, the stent of the present application can also be prepared by 3D printing.

[0022] The stent of the present application provides a first transition portion between the front end portion and the middle portion of the stent, which connects the front end portion and the middle portion in part of the circumference of the tube of the stent, for example, a first part of the front end portion is connected to the middle portion by the first transition portion in the axial direction of the stent, and on the contrary, a second part of the front end portion is directly connected to the middle portion without the first transition portion. This can make the stent have different properties of radial support or flexibility at the first transition portion and other parts of the circumference, and it can be appreciated that the first transition portion and the other parts are connected in the circumference to form a continuous circumference of the tube of the stent, for example, the local connection of the first transition portion and the second part forms a continuous circumference of the tube of the stent, or the local connection of the first transition portion and the middle portion forms a continuous circumference of the tube of the stent, or the local connection of the first transition portion and the second part and the local connection of the middle portion form a continuous circumference of the tube of the stent.

[0023] Among them, the first transition portion, the first part and the second part of the front end portion, and the front end portion can be selected to have different properties of radial support or axial bending flexibility, for example, the first transition portion can have better support performance than the first part, the second part of the front end portion and the middle portion, to provide strong support performance of the tube of the stent at the first transition portion; or the first transition portion can have better flexibility than the first part, the second part of the front end portion and the middle portion, to provide excellent performance of the tube of the stent at the first transition portion to adapt to the tortuosity or bending of the lumen; or the first transition portion can have better flexibility than the first part of the front end portion, and at the same time, have stronger support performance than the second part of the front end portion and the middle portion.

[0024] As a preference, the first part and the second part of the front end portion can have substantially the same or similar performance but have different style designs, and the first transition portion has a more flexible performance than the first part and the second part of the front end portion and has a stronger support performance than the middle portion.

[0025] The above design is advantageous for the treatment of the special lesion segment lumen, which is affected by special biological anatomy and / or surrounding tissue, and an isotropic stent can not be suitable for the special lesion segment lumen, for example, iliac vein stenosis lesion.

[0026] The stent of the present application can provide the differential radial support or flexible performance of the different parts as described above, and can adapt to the treatment requirements of the special lesion segment lumen.

[0027] In one embodiment of the present application, the front end portion is provided with a bevel at the other end of the tube body not connected to the middle portion, the bevel has a distal end point and a proximal end point, a line between the distal end point and the proximal end point has a preset included angle with the central axis of the stent, the line divides the stent into two half-circumferential tube bodies along the axial direction of the stent, and the first transition portion is located in one of the half-circumferential tube bodies. The support performance of the first transition portion can be between the front end portion and the middle portion, and the support performance of the half-circumferential tube body provided with the first transition portion is greater than that of the half-circumferential tube body not provided with the first transition portion. When the bevel stent is applied to the left iliac vein blood vessel, the left iliac vein blood vessel is between the fifth lumbar vertebra and the right common iliac artery, wherein, on the side of the fifth lumbar vertebra, the left iliac vein blood vessel extends in the direction of the femoral vein after leaving the fifth lumbar vertebra and forms a large physiological bend, at this position, the half-circumferential tube body of the stent not provided with the first transition portion has higher flexibility, and on the side of the right common iliac artery, the left iliac vein blood vessel is compressed by the right common iliac artery with higher blood pressure to form a stenosis on the side of the fifth lumbar vertebra, at this position, the half-circumferential tube body of the stent provided with the first transition portion provides higher support performance, so that the first transition portion faces and resists the compression of the right common iliac artery, and can have better support performance, and the other half-circumferential tube body corresponding to the first transition portion faces and conforms to the fifth lumbar vertebra and extends in the direction of the femoral vein, the support performance of the first transition portion is stronger than that of the corresponding half-circumferential tube body, and the flexible performance of the corresponding half-circumferential tube body is stronger, which can adapt to the large bending of the left iliac vein blood vessel caused by the compression of the fifth lumbar vertebra.

[0028] It can be understood that the above design is also applicable to the stent without the bevel.

[0029] The bending performance or support performance of the half-circumferential tube body of the first transition portion and the other half-circumferential tube body opposite thereto can be tested and compared by various methods known to those skilled in the art. One simple method is to use the half-circumferential tube body as the inflection point of the bending, and test the difficulty of bending the stent at the inflection point.

[0030] In one embodiment of the present application, the first portion has a first face adjacent to the intermediate portion in the radial direction of the tube body, and the second portion has a second face adjacent to the first transition portion in the radial direction of the tube body, the second face is not coplanar with the first face, or the second face and the first face are respectively deviated to different sides of the radial cross section of the tube body. Since the second face of the present application is not coplanar with the first face, that is, the axial length of the first portion along the stent is not equal to that of the second portion, for example, the axial length of the first portion along the stent is greater than that of the second portion.

[0031] In one embodiment of the present application, the intermediate portion has a third face adjacent to the first portion in the radial direction of the tube body, and the third face coincides with the first face. The direct splicing of the first portion and the intermediate portion can realize the rapid transition of the stent in the axial direction and reduce the occupied area of the transition portion in the stent.

[0032] In one embodiment of the present application, the length of the first transition portion along the circumferential direction of the stent is less than the circumference of the radial cross section of the stent where the first transition portion is located, and preferably, the ratio of the lengths is 2 / 3, or 1 / 2, or 1 / 3, or 1 / 4, or between 1 / 4 and 2 / 3.

[0033] In one embodiment of the present application, the axial length of the first transition portion of the stent in the unbound state is 6.0-9.5 mm. The axial length of the first transition portion generally refers to the maximum length in the axial direction.

[0034] In one embodiment of the present application, the first portion comprises a plurality of first wave-shaped rods arranged in the axial direction of the stent, the first wave-shaped rods extend along the circumferential direction of the stent and have wave troughs and wave crests alternately distributed along the length direction thereof, and each two adjacent first wave-shaped rods are connected at the wave crests or wave troughs, so that the first portion has a mesh structure.

[0035] The second portion comprises a plurality of second wave-shaped rods arranged in the axial direction of the stent, the second wave-shaped rods extend along the circumferential direction of the stent and have wave troughs and wave crests alternately distributed along the length direction thereof, and each two adjacent second wave-shaped rods are connected at the wave crests or wave troughs, so that the second portion has a mesh structure.

[0036] The first transition portion comprises at least one third wave-shaped rod, the third wave-shaped rod extends along the circumferential direction of the stent and has wave troughs and wave crests alternately distributed along the length direction thereof.

[0037] The intermediate portion comprises a spiral segment, the spiral segment comprises at least one fourth wave-shaped rod extending along a spiral line in the circumferential direction of the tube body, the fourth wave-shaped rod has wave troughs and wave crests alternately distributed along the length direction thereof; wherein,

[0038] The first portion and the helical segment of the intermediate portion are connected at adjacent positions by forming a connection at each adjacent wave crest or wave trough, the second portion and the first transition portion are connected at adjacent positions by forming a connection at each adjacent wave crest or wave trough, and the first transition portion and the helical segment of the intermediate portion are connected at adjacent positions by forming a connection at each adjacent wave crest or wave trough.

[0039] In one embodiment of the present application, the first portion and the intermediate portion are connected at adjacent positions by connecting a partial wave trough of the first wave-shaped rod with a partial wave crest of the fourth wave-shaped rod, the second portion and the first transition portion are connected at adjacent positions by connecting a partial wave trough of the second wave-shaped rod with a partial wave crest of the third wave-shaped rod, and the first transition portion and the intermediate portion are connected at adjacent positions by connecting a partial wave trough of the third wave-shaped rod with a partial wave crest of the fourth wave-shaped rod. By connecting the first portion and the intermediate portion at adjacent positions by connecting a partial wave trough with a partial wave crest, connecting the second portion and the first transition portion at adjacent positions by connecting a partial wave trough with a partial wave crest, and connecting the first transition portion and the intermediate portion at adjacent positions by connecting a partial wave trough with a partial wave crest, a smooth transition of the axial support performance and the flexibility performance of the first portion to the intermediate portion, the second portion to the first transition portion, and the first transition portion to the intermediate portion can be achieved.

[0040] In one embodiment of the present application, the helical segment comprises two fourth wave-shaped rods extending in a helical line, and the two fourth wave-shaped rods are connected by a connecting rod and extend in the same direction around the central axis of the stent.

[0041] In one embodiment of the present application, the first transition portion and the second portion of the front end portion and the intermediate portion are respectively formed by different unit structures. This can make different parts of the stent have different performances, thereby meeting the demand of the iliac vein blood vessel for the diversity of the performance of the stent.

[0042] In one embodiment of the present application, the third wave-shaped rod comprises:

[0043] a first sub-wave-shaped rod; and

[0044] a second sub-wave-shaped rod, the second sub-wave-shaped rod and the first sub-wave-shaped rod are arranged along the circumference of the stent, and the second sub-wave-shaped rod is connected with the first sub-wave-shaped rod; wherein the length of the first sub-wave-shaped rod and the second sub-wave-shaped rod gradually decreases or gradually increases along the wave height of the circumference of the stent. The structure design of the third wave-shaped rod can cooperate with the double-helical structure of the intermediate portion to realize the connection of the intermediate portion and the first transition portion, and can further reduce the occupied area of the first transition portion, thereby increasing the occupied space of the flexible area and meeting the demand of the iliac vein stent for the flexible stent.

[0045] In one embodiment of the present application, the first part of the plurality of first wave-shaped rods gradually changes the angle with the central axis of the stent. The advantage of this design is that it can achieve uniform transition of the angle of the plurality of first wave-shaped rods of the first part, and can also achieve uniform expansion of the first part.

[0046] In one embodiment of the present application, the second part of the plurality of second wave-shaped rods gradually changes the angle with the central axis of the stent. On the one hand, it can achieve uniform transition of the angle of the plurality of second wave-shaped rods of the second part, and on the other hand, it can also achieve uniform expansion of the second part.

[0047] In one embodiment of the present application, the stent further comprises:

[0048] A second transition part, the second transition part constitutes a section of the pipe body of the stent, and is adjacent to and connected to the other side of the intermediate part away from the front end part; and

[0049] A terminal part, the terminal part constitutes another end part of the pipe body of the stent, and is adjacent to and connected to the other side of the second transition part away from the intermediate part. By providing the second transition part, on the one hand, it can achieve performance transition of the terminal part and the intermediate part, and on the other hand, it can meet the needs of the stent for different parts of the iliac vein blood vessel.

[0050] The present application also provides an application of the tubular stent as an iliac vein stent.

[0051] In one embodiment of the present application, when the tubular stent is applied to the left iliac vein blood vessel, the first transition part of the half-pipe body of the stent is used to resist the compression of the right common iliac artery, and the other half-pipe body of the stent is used to conform to the blood vessel of the fifth lumbar vertebra towards the femoral vein.

[0052] The present application provides a preparation method of the above-mentioned tubular stent, which comprises the steps of cutting a pipe material by laser and removing the excess part of the pipe material to obtain the pipe body of the stent with hollows.

[0053] Compared with the prior art, the tubular stent of the present application can directly connect the first part of the front end part with the intermediate part, can achieve rapid transition of the performance of the stent in the axial direction, can provide flexible change between different performance sections of the stent, can reduce the occupied area of the transition part in the stent, can reduce the influence of the non-uniformly distributed support structure in the transition part on the uniform expansion performance of the stent, can provide a larger effective design area of the stent, can meet the clinical needs, and the second part can be connected with the intermediate part through the first transition part, and can achieve connection and performance transition of the front end part and the intermediate part. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 This is a three-dimensional structural schematic diagram of an embodiment of the lumen stent provided in this application;

[0055] Figure 2 yes Figure 1 A front view of an embodiment of the central lumen stent;

[0056] Figure 3 yes Figure 1 A schematic diagram of the planar unfolded structure of an embodiment of a lumen support;

[0057] Figure 4 This is a schematic diagram showing the position of a stent with an oblique opening placed in the left iliac vein.

[0058] Figure 5 yes Figure 3 Enlarged schematic diagram of the front part, the first transition part, and the middle part;

[0059] Figure 6 yes Figure 3 A partial schematic diagram of the middle section shown;

[0060] Figure 7 yes Figure 3 A partially enlarged schematic diagram of the first transition section and its surroundings at a certain scale;

[0061] Figure 8 yes Figure 3 A magnified view of the first transition section and its surrounding area at another scale. Detailed Implementation

[0062] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0063] This invention provides a stent for placement in the diseased segment of a lumen to support the narrowed or occluded segment and maintain lumen patency. It is particularly suitable for intravascular implantation in complex lesions. Through the design of the stent's transition section, it endows different parts of the stent with differentiated support, compliance, and positioning properties to fully adapt to the special physiological environment of blood vessels or other lumens and improve the therapeutic effect.

[0064] In the embodiment of the present invention, the support is a hollow tube, which can be divided into a front end and a middle part along the axial direction of its cavity, each constituting a segment of the support tube body. The front end is located at one end of the support and includes a first part and a second part. The first part and the second part are arranged and connected along the circumference of the support. The first part of the front end is adjacent to and connected to the middle part along the axial direction of the support. The second part of the front end is not directly connected to the middle part along the axial direction of the support. A first transition part is provided between the second part and the middle part. The second part of the front end is connected to the middle part through the first transition part.

[0065] It can be understood that the front end portion, the first transition portion and the intermediate portion jointly constitute the stent tube body, or at least constitute a major part of the stent tube body. The connection of the front end portion and the intermediate portion in the circumferential direction of the stent tube body can be discontinuous and ends at the first transition portion, which is formed on a part of the tube circumference, like a patch, between the second part of the front end portion and the intermediate portion, so as to present a complete stent tube body.

[0066] The differentiated design of the front end portion and the intermediate portion is very advantageous for the implementation of the embodiment scheme of the present application, which is well known to those skilled in the art that, in addition to the material, the pattern design of the stent has an important influence on the performance of the stent, and the pattern design of the stent mainly includes the circumferential support body constituting the stent and the connecting piece connecting the circumferential support bodies in the axial direction. The differentiated design of the front end portion and the intermediate portion can be realized by using different patterns of circumferential support bodies. For example, one of the prior art stents sequentially includes a non-spiral circumferential support body, a circumferential transition region and a spiral circumferential support body along the axial direction thereof.

[0067] And the embodiment of the present application directly connects the first part of the front end portion with the intermediate portion along the axial direction of the stent, and connects the second part of the front end portion with the intermediate portion through the first transition portion, which not only realizes the axial splicing of the two parts with relatively large performance difference, but also realizes the existence of performance difference in the circumferential direction of the stent between the front end portion and the intermediate portion of the stent, so as to meet the needs of special lumens such as iliac veins for different support performances of different parts of the stent.

[0068] Among them, the front end portion, the first transition portion and the intermediate portion can jointly constitute an independent stent, and the other end of the intermediate portion relative to the connection of the front end portion and the intermediate portion constitutes the end of the stent.

[0069] It can be understood that, in some embodiments, the front end portion, the first transition portion and the intermediate portion can jointly constitute an independent stent with another part, for example, the other end of the intermediate portion relative to the connection of the front end portion and the intermediate portion is connected with an end portion constituting a tube segment, and the end portion constitutes the other end of the stent relative to the front end portion.

[0070] It can be understood that, in some embodiments, the stent tube body includes an end portion, a second transition portion which is symmetrical or asymmetrical to the front end portion and the first transition portion, for example, the other end of the intermediate portion relative to the connection of the front end portion and the intermediate portion is connected with an end portion constituting a tube segment, and the end portion constitutes the end of the stent, and the second transition portion is located between the end portion and the intermediate portion and constitutes a tube segment of the stent, and the second transition portion is used to realize the splicing of the intermediate portion and the end portion.

[0071] In the embodiment of the present application, the front end portion and the intermediate portion of the stent, and the end portion can be respectively constituted by different unit structures. The first transition portion and the second transition portion are usually different from the foregoing unit structures.

[0072] For example, the front end portion of the stent can be composed of the same repeating arrangement of unit mesh support structures, and the middle portion can be composed of repeating arrangement of circumferential spiral support structures or annular circumferential support structures. In a preferred embodiment of the present application, the first portion and the second portion of the front end portion are composed of different repeating arrangement of unit mesh support structures, for example, the unit meshes have different shapes, or the orientations of the unit meshes have significant differences.

[0073] It can be understood that the unit mesh support structures, the circumferential spiral support structures, and the annular circumferential support structures correspond to the pattern design of different regions of the stent, and the unit meshes and the circumferential spiral support structures or the annular circumferential support structures form the hollow or pores around the tube of the stent with the axial connecting rods.

[0074] The present application is further illustrated below.

[0075] Please refer to Figure 1 , Figure 2 and Figure 3 , the lumen stent 100 is provided as a hollow tube, and the stent 100 includes a front end portion 10, a middle portion 20, and a first transition portion 30. The front end portion 10 forms an end tube of the stent 100, and the front end portion 10 includes a first portion 11 and a second portion 12. The first portion 11 and the second portion 12 are arranged along the circumference of the stent and are connected.

[0076] The middle portion 20 forms a tube of the stent 100, and the middle portion 20 is adjacent to and connected with the first portion 11 of the front end portion 10.

[0077] The first portion 11 and the second portion 12 are connected to form an annular tube of the front end portion 10 of the stent, but the first portion 11 and the second portion 12 can have different lengths along the axial direction of the stent.

[0078] The first transition portion 30 is located between the second portion 12 of the front end portion 10 and the middle portion 20, and the second portion 12 of the front end portion 10 is connected with the middle portion 20 through the first transition portion 30. Since the first portion 11 of the front end portion 10 is directly connected with the middle portion 20, no transition section is needed, which can achieve a rapid transition of different performances of the stent in the axial direction and reduce the occupied area of the transition portion in the stent. The second portion is connected with the middle portion through the first transition portion, which can achieve the connection and performance transition of the front end portion and the middle portion.

[0079] And, since no transition section is arranged between the first part 11 of the front end part 10 and the middle part 20, the machining process and machining cost of the transition section can be saved. As known by those skilled in the art, a stent design forms a product, which usually needs to be provided in multiple specifications in different sizes and lengths to meet medical needs. The transition section is designed as a specific design, which usually needs to be designed separately in different specifications, which leads to great difficulty and workload in the design and machining of the multiple-specification stent product. Reducing the area of the transition part can effectively improve these problems.

[0080] The second part 12 of the front end part 10 is connected with the middle part 20 through the first transition part 30, so that there is a performance difference between the front end part 10 and the middle part 20 of the stent 100 in the circumferential direction of the stent 100, which can meet the demand of the same circumferential part of the iliac vein for different performances of the stent. For example, when the stent is applied to the iliac vein, since the proximal end of the stent is used to resist the compression of the right common iliac artery and the fifth lumbar vertebra, after the left iliac vein vessel leaves the fifth lumbar vertebra, it needs to be physiologically curved towards the direction of the femoral vein, and the flexibility of the stent is required to be higher; while on the side of the right common iliac artery, the left iliac vein vessel is compressed by the right common iliac artery, and the supportability of the stent is required to be higher, therefore, it is necessary to provide a difference in performance between the front end part and the middle part of the stent in the circumferential direction of the stent, so as to meet the demand of the same circumferential position of the iliac vein vessel for different performances of the stent.

[0081] The support performance of the front end part 10 is usually selected to be greater than that of the first transition part 30, and the support performance of the first transition part 30 is greater than that of the middle part 20, that is, the flexibility of the front end part 10 is less than that of the first transition part 30, and the flexibility of the first transition part 30 is less than that of the middle part 20. Since the first part 11 of the front end part 10 and the middle part 20 can be directly spliced without the need to arrange a transition section, only the first transition part 30 needs to be arranged between the second part 12 of the front end part 10 and the middle part 20, and since no transition section is arranged between the first part 11 of the front end part 10 and the middle part 20, the flexibility of the stent also changes greatly when the structure of the stent changes from the first part 11 to the middle part 20, which can make the middle part 20 near the first part 11 be able to bend greatly to conform to the vessel of the fifth lumbar vertebra towards the direction of the femoral vein, realize good stent adhesion, meet the demand of the iliac vein vessel for flexibility, and the first transition part 30 is used to resist the compression of the right common iliac artery, and meet the demand of the iliac vein vessel for supportability.

[0082] Further preferred embodiments of the stent described above can also be provided.

[0083] Please continue to refer to Figure 3 and refer to Figure 4, the front end part 10 is provided with a bevel at the other end of the tube body not connected with the middle part 20, that is, the front end part 10 is provided with a bevel at the end far away from the middle part 20, when the stent is applied to the left iliac vein blood vessel, the bevel of the front end part 10 of the stent is matched with the left iliac vein end part, and can be matched with the left iliac vein blood vessel, so as to reduce the obstruction of the stent to the blood flow of the right blood vessel when entering the iliac vein blood vessel, and avoid the formation of thrombus. Similarly, it can also be applied to the right iliac vein blood vessel, which will not be described one by one here.

[0084] The inclination angle of the bevel of the stent end part can be consistent with the inclination angle of the left iliac vein end part, so that when the stent enters the left iliac vein blood vessel, the distal end point of the farthest end of the bevel of the stent and the proximal end point of the nearest end respectively abut the left iliac vein blood vessel, and the support area of the stent to the iliac vein blood vessel can be improved.

[0085] Referring to Figure 2 The bevel has a distal end point 102 and a proximal end point 103, and the line D1-D2 between the distal end point 102 and the proximal end point 103 has a preset included angle with the central axis 60 of the stent 100, and the preset included angle is the inclination angle of the bevel. The preset included angle is an acute angle, for example, the preset included angle is 20-85 degrees, preferably the preset included angle is 30-70 degrees, and in the embodiment of the present application, the preset included angle is 67 degrees. The inclination angle of the bevel of the front end part 10 of the stent 100 is consistent with the included angle of the left iliac vein and the right iliac vein in the iliac vein blood vessel, which can avoid obstructing the blood flow of the right common iliac vein to the inferior vena cava, and can increase the effective area of the support function.

[0086] The line D1-D2 divides the stent 100 into two half circles of the tube body along the axial direction of the stent 100, and the first transition part 30 is located in one of the half circles of the tube body, that is, the first half circle tube body and the second half circle tube body. The first transition part 30 is located in the first half circle tube body or the second half circle tube body, for example, when the stent 100 is applied to the left iliac vein blood vessel, the first transition part 30 can be located in the first half circle tube body. The left iliac vein blood vessel is compressed between the fifth lumbar vertebra and the right common iliac artery, and after leaving the fifth lumbar vertebra, the left iliac vein blood vessel needs to be physiologically curved towards the femoral vein, so the compliance of the stent is required to be higher. On the side of the right common iliac artery, the left iliac vein blood vessel is compressed by the right common iliac artery, so the supportability of the stent is required to be higher. Therefore, the first transition part 30 on the first half circle tube body is used to resist the compression of the right common iliac artery, and the half circle corresponding to the first transition part 30 on the second half circle tube body is used to conform to the blood vessel towards the femoral vein direction of the fifth lumbar vertebra. Correspondingly, the support performance of the first transition part 30 is stronger than that of the corresponding half circle, and the first transition part 30 can more effectively resist the elastic compression of the right common iliac artery, and the corresponding half circle has stronger compliance and can adapt to the large curvature of the left iliac vein blood vessel compressed by the fifth lumbar vertebra.

[0087] Similarly, when the stent 100 is applied to the right iliac vein, the first transition section 30 can also be located at the second half-week pipe body.

[0088] In the above iliac vein, although in the same circumferential position, the performance requirements of the stent are different. In the area to ensure the resistance to compression of the proximal end, the compliance area is required to be maximized as much as possible. Therefore, the transition between the two different structure designs requires a sudden change.

[0089] As can be understood by those skilled in the art, in addition to the above embodiments, the front end 10 of the stent 100 can also be provided as a flat mouth, which can be applicable to a non-beveled lumen.

[0090] Please continue to refer to Figure 3 , the first part 11 has a first face 110 adjacent to the intermediate part 20 in the radial direction of the pipe body of the stent 100, the second part 12 has a second face 120 adjacent to the first transition section 30 in the radial direction of the pipe body of the stent 100, and the intermediate part 20 has a third face 201 adjacent to the first part 11 in the radial direction of the pipe body of the stent 100. Wherein, the first face 110 coincides with the third face 201, the second face 120 is not coplanar with the first face 110, or the second face is deviated to different sides of the radial cross section of the pipe body of the stent 100, that is, the second face 120 and the first face 110 have a preset included angle, which can be an acute angle, a right angle or an obtuse angle, for example, the preset included angle between the second face 120 and the first face 110 is 30 degrees, 45 degrees, 60 degrees, 105 degrees or 120 degrees, and the preset included angle between the second face 120 and the first face 110 in the embodiment is preferably 120 degrees. The second face 120 and the first face 110 are not coplanar, on the one hand, the area between the front end 10 and the intermediate part 20 can realize the performance difference in the circumferential direction of the stent, and meet the different performance requirements of the iliac vein at the same circumferential position; on the other hand, the third face 103 coincides with the first face 110, which can realize the direct splicing of the first part 11 and the intermediate part 20, realize the rapid transition of the performance of the first part 11 and the intermediate part 20, and reduce the occupied area of the transition section; on the other hand, the first part 11 and the intermediate part 20 do not need to be provided with a transition section, which can save the processing procedure, save the processing cost, and improve the processing efficiency of the stent.

[0091] It can be understood that in some embodiments, the first part 11 and the second part 12 are not equal in the axial length of the stent, for example, see Figure 3 , the axial length of the first part 11 is greater than that of the second part 12, the first part 11 and the intermediate part 20 are not provided with the first transition section 30, and the second part 12 and the intermediate part 20 are provided with the first transition section 30.

[0092] It can be understood that, in some embodiments, the axial length of the first portion 11 can also be less than or equal to the axial length of the second portion 12. When the axial length of the first portion 11 is less than or equal to the second portion 12, because no transition section is arranged between the first portion 11 and the intermediate portion 20, and the first transition section 30 is arranged between the second portion 12 and the intermediate portion 20, the area between the first portion 11 and the intermediate portion 20 opposite the first transition section 30 is filled with the intermediate portion 20, and the intermediate portion 20 accordingly increases the occupied area of the stent, so that the compliant area of the stent is increased, which can meet the demand of the iliac vein blood vessel for compliance.

[0093] Non-limitingly, the specific style structure of the stent described above can be realized by the following scheme.

[0094] Please refer to Figure 5 , the first portion 11 includes a plurality of first wave-shaped rods 111 arranged along the axial direction of the stent 100, the first wave-shaped rods 111 extend along the circumferential direction of the stent 100 and have wave troughs and wave crests alternately distributed along the length direction thereof, and each two adjacent first wave-shaped rods 111 are connected at the wave crests and the wave troughs, so that the first portion 11 has a net structure.

[0095] Specifically, please refer to Figure 5 , the first portion 11 includes a first wave-shaped rod 111a, a first wave-shaped rod 111b, a first wave-shaped rod 111c, a first wave-shaped rod 111d, and a first wave-shaped rod 111e, the first wave-shaped rod 111a, the first wave-shaped rod 111b, the first wave-shaped rod 111c, the first wave-shaped rod 111d, and the first wave-shaped rod 111e are arranged along the axis of the stent 100, and the first wave-shaped rod 111e is arranged adjacent to the intermediate section 20.

[0096] Among them, the adjacent two first wave-shaped rods 111 are connected to form a plurality of quadrilateral closed rings arranged along the circumferential direction of the stent. For example, the first wave-shaped rod 111a and the first wave-shaped rod 111b are connected to form a plurality of quadrilateral closed rings arranged along the circumferential direction of the stent, the first wave-shaped rod 111b and the first wave-shaped rod 111c are connected to form a plurality of quadrilateral closed rings arranged along the circumferential direction of the stent, the first wave-shaped rod 111c and the first wave-shaped rod 111d are connected to form a plurality of quadrilateral closed rings arranged along the circumferential direction of the stent, and the first wave-shaped rod 111d and the first wave-shaped rod 111e are connected to form a plurality of quadrilateral closed rings arranged along the circumferential direction of the stent. Because the first portion 11 of the front end portion is formed by a plurality of quadrilateral closed rings, the structure of the closed ring is relatively stable, so that the front end portion 10 has good support performance.

[0097] The inclination angle of each of the first wave-shaped rods 111 of the first portion 11 with respect to the central axis 60 of the stent 100 is different. The inclination angle of the first wave-shaped rods 111 of the first portion 11 can be uniformly transitioned, so that the inclination angle of the first wave-shaped rod 111e on the side adjacent to the intermediate portion 20 is the same as the inclination angle of the intermediate portion 20, thereby achieving seamless splicing of the first portion 11 and the intermediate portion 20 through the first wave-shaped rods 111, and further saving the space required for setting a transition zone.

[0098] It can be understood that the difference between the inclination angles of each of the two adjacent first wave-shaped rods 111 with respect to the central axis 60 of the stent 100 is within a predetermined range, and preferably the difference between the inclination angles of each of the two adjacent first wave-shaped rods 111 with respect to the central axis 60 of the stent 100 is equal. The inclination angle of the first wave-shaped rods 111 of the first portion 11 can be uniformly transitioned, so that the first portion 11 has a uniform tension, and the first portion 11 can be uniformly expanded.

[0099] For example, the first wave-shaped rod 111a has an inclination angle α1 with respect to the central axis 60 of the stent 100, the first wave-shaped rod 111b has an inclination angle α2 with respect to the central axis 60 of the stent 100, the first wave-shaped rod 111c has an inclination angle α3 with respect to the central axis 60 of the stent 100, the first wave-shaped rod 111d has an inclination angle α4 with respect to the central axis 60 of the stent 100, the first wave-shaped rod 111e has an inclination angle α5 with respect to the central axis 60 of the stent 100, and the spiral segment 21 of the intermediate portion 20 has an inclination angle α6 with respect to the central axis 60. The difference between the inclination angle α1 and the inclination angle α2 is equal to the difference between the inclination angle α2 and the inclination angle α3, the difference between the inclination angle α2 and the inclination angle α3 is equal to the difference between the inclination angle α3 and the inclination angle α4, and the difference between the inclination angle α3 and the inclination angle α4 is equal to the difference between the inclination angle α4 and the inclination angle α5. On the one hand, the inclination angle α1 of the first wave-shaped rod 111a to the inclination angle α5 of the first wave-shaped rod 111e can be uniformly transitioned, so that the inclination angle α5 is equal to the inclination angle α6 of the intermediate portion 20 with respect to the central axis 60 of the stent 100, and on the other hand, the first portion 11 can be uniformly expanded.

[0100] It should be noted that the inclination angle of the first wave-shaped rod 111 with respect to the central axis 60 can be the included angle between the connecting line of all wave crests of the first wave-shaped rod 111 and the central axis 60, and the inclination angle of the spiral segment 21 with respect to the central axis 60 can be the included angle between the connecting line of all wave crests of the fourth wave-shaped rod and the central axis 60.

[0101] Please continue to readFigure 5 The second portion 12 comprises a plurality of second wave-shaped rods 121 arranged along the axial direction of the stent 100, the second wave-shaped rods 121 extend along the circumferential direction of the stent 100 and have wave troughs and wave crests alternatingly arranged along the length direction thereof, and each two adjacent second wave-shaped rods 121 are connected at the wave crests and the wave troughs, so that the second portion 12 has a mesh structure.

[0102] The second portion 12 comprises a second wave-shaped rod 121a, a second wave-shaped rod 121b, a second wave-shaped rod 121c and a second wave-shaped rod 121d, the second wave-shaped rod 121a, the second wave-shaped rod 121b, the second wave-shaped rod 121c and the second wave-shaped rod 121d are arranged along the axial direction of the stent 100, and the second wave-shaped rod 121d is arranged adjacent to the first transition portion 30.

[0103] The second wave-shaped rods 121 are connected to each other to form a plurality of quadrilateral closed rings arranged along the circumferential direction of the stent. For example, the second wave-shaped rod 121a and the second wave-shaped rod 121b are connected to each other to form a plurality of quadrilateral closed rings arranged along the circumferential direction of the stent, the second wave-shaped rod 121b and the second wave-shaped rod 121c are connected to each other to form a plurality of quadrilateral closed rings arranged along the circumferential direction of the stent, and the second wave-shaped rod 121c and the second wave-shaped rod 121d are connected to each other to form a plurality of quadrilateral closed rings arranged along the circumferential direction of the stent. Since the second portion 11 of the front end portion is formed by a plurality of quadrilateral closed rings, the structure of the closed rings is relatively stable, so that the front end portion 10 has good support performance.

[0104] The second wave-shaped rods 121 of the second portion 12 and the central axis 60 of the stent 100 have different inclination angles.

[0105] The difference between the inclination angles of each two adjacent second wave-shaped rods 121 and the central axis 60 of the stent 100 is within a preset range, and preferably, the difference between the inclination angles of each two adjacent second wave-shaped rods 121 and the central axis 60 of the stent 100 is equal. The inclination angles of the second wave-shaped rods 121 of the second portion 12 can be uniformly transitioned, so that the second portion 12 has uniform tension and can be uniformly expanded.

[0106] For example, the second wave-shaped rod 121a has an inclination angle β1 with the central axis 60 of the stent 100, the second wave-shaped rod 121b has an inclination angle β2 with the central axis 60 of the stent 100, the third wave-shaped rod 121c has an inclination angle β3 with the central axis 60 of the stent 100, and the second wave-shaped rod 121d has an inclination angle β4 with the central axis 60 of the stent 100. The difference between the inclination angle β1 and the inclination angle β2 is equal to the difference between the inclination angle β2 and the inclination angle β3, and the difference between the inclination angle β2 and the inclination angle β3 is equal to the difference between the inclination angle β3 and the inclination angle β4. On the one hand, this can realize the uniform transition between the inclination angle β1 of the second wave-shaped rod 121a and the inclination angle β4 of the second wave-shaped rod 121d. On the other hand, this can realize the uniform expansion of the second part 12.

[0107] It should be noted that the inclination angle of the second wave-shaped rod 121 with the central axis 60 can be the included angle between the connecting line of all troughs of the second wave-shaped rod 121 and the central axis 60, or the included angle between the connecting line of all peaks formed by the second wave-shaped rod 121 and the central axis 60.

[0108] The area of the first part 11 of the stent 100 can be the same as or different from the area of the second part 12. For example, the area of the first part 11 of the stent 100 can be greater than or less than the area of the second part 12. When the area of the first part 11 is greater than the area of the second part 12, since the first part 11 is directly connected to the intermediate part 20 and the second part 12 is connected to the intermediate part 20 through the first transition part 30, and the support performance of the intermediate part 20 is less than that of the first transition part 30, the area of the region where the support performance of the two half-tube bodies is similar is close to the same by increasing the area of the first part 11.

[0109] The intermediate part 20 includes a spiral segment 21, and the spiral segment 21 includes at least one fourth wave-shaped rod 211 extending along a spiral line around the tube. The fourth wave-shaped rod 211 has troughs and peaks alternatingly distributed along the length direction thereof. The spiral segment 21 includes two fourth wave-shaped rods 211 extending along spiral lines, and the two fourth wave-shaped rods 211 are connected by a connecting rod 212 and extend in the same direction around the central axis 60 of the stent 100. The connecting rod 212 connects the peaks or troughs of the two fourth wave-shaped rods 211.

[0110] Please refer to Figure 6a2 and al, c2 and cl, e2 and el, g2 and gl, I2 and II of the intermediate portion 30 are the breakpoints when the first fourth wave-shaped rod is unfolded, b2 and bl, d2 and dl, f2 and fl, h2 and hl are the breakpoints when the second fourth wave-shaped rod is unfolded, and the two fourth wave-shaped rods are connected in sequence according to the aforementioned breakpoint combinations to form a double-helix structure of two fourth wave-shaped rod combinations, and the two fourth wave-shaped rods are approximately cylindrical helical lines spirally surrounding the tubular central axis to form a double-helix flexible tubular support structure.

[0111] Obviously, those skilled in the art can also adopt more fourth wave-shaped rods arranged at intervals to form a multi-helix flexible tubular support structure. For example, 3, 4 or 5 fourth wave-shaped rods are arranged at intervals, and each wave-shaped rod is approximately a cylindrical helical line spirally surrounding the tubular central axis to form a three-helix, four-helix or five-helix flexible tubular support structure.

[0112] The first transition portion 30 comprises at least one third wave-shaped rod 31 extending along the circumference of the stent and having wave troughs and wave crests alternately distributed along the length direction thereof.

[0113] In the embodiment, the first portion 11 and the spiral segment 21 of the intermediate portion 20 are connected at the adjacent positions by forming connections at the respective adjacent wave crests and wave troughs, the second portion 12 and the first transition portion 30 are connected at the adjacent positions by forming connections at the respective adjacent wave crests and wave troughs, and the first transition portion 30 and the spiral segment 21 of the intermediate portion 20 are connected at the adjacent positions by forming connections at the respective adjacent wave crests and wave troughs.

[0114] In the embodiment, the first portion 11 and the intermediate portion 20 are connected at the adjacent positions by connecting the partial wave troughs of the first wave-shaped rod 111 with the partial wave crests of the fourth wave-shaped rod 211, the second portion 12 and the first transition portion 30 are connected at the adjacent positions by connecting the partial wave troughs of the second wave-shaped rod 121 with the partial wave crests of the third wave-shaped rod 31, and the first transition portion 30 and the intermediate portion 20 are connected at the adjacent positions by connecting the partial wave troughs of the third wave-shaped rod 31 with the partial wave crests of the fourth wave-shaped rod 211.

[0115] For example, Figure 5 It is shown that the five wave troughs of the first portion 11 adjacent to the spiral segment 21 of the intermediate portion 20 are connected with the five wave crests of the intermediate portion 20.

[0116] Non-limitingly, those skilled in the art can also select more or less than five wave crests or wave troughs, and the five wave crests / wave troughs connected can be adjacent in the circumferential direction of the stent or arranged at intervals.

[0117] The four valleys of the second part 12 adjacent to the first transition part 30 are connected with the four peaks of the first transition part 30, wherein the four peaks or valleys can be adjacent or spaced apart. It can be understood that the number of peaks or valleys of the second part 12 connected with the first transition part 30 can not be limited to the above number, and can be set according to actual needs.

[0118] The four valleys of the first transition part 30 adjacent to the middle part 20 are connected with the four peaks of the middle part 20, wherein the four peaks or valleys can be adjacent or spaced apart. It can be understood that the number of peaks or valleys of the first transition part 30 connected with the middle part 20 can not be limited to the above number, and can be set according to actual needs.

[0119] Please continue to refer to Figure 5 , the first transition part 30 includes a third wave-shaped rod 31, and the third wave-shaped rod 31 includes a first sub-wave-shaped rod 311 and a second sub-wave-shaped rod 312, wherein the first sub-wave-shaped rod 311 and the second sub-wave-shaped rod 312 gradually decrease or gradually increase in wave height along the circumference of the stent 100. For example, the length of the first sub-wave-shaped rod 311 gradually decreases in wave height from the M end to the L end to form a small trapezoidal area; the length of the second sub-wave-shaped rod 312 gradually decreases in wave height from the L end to the N end to form a small trapezoidal area. Compared with the first transition part composed of a third wave-shaped rod with a wavelength gradient, the first transition part 30 composed of two sub-wave-shaped rods 311 and 312 with a wavelength gradient can have a smaller area. It can be easily understood that the former first transition part is similar to a large trapezoidal area, while the latter first transition part 30 is similar to two consecutive small trapezoidal areas, see Figure 3 .

[0120] Since the first transition part 30 is composed of two small trapezoids, the area occupied by the first transition part 30 in the stent 100 can be further reduced, thereby increasing the area of the compliant region and maximizing the design of the compliant region, so as to transition the performance of the flexibility and supportability of the stent and meet the needs of the iliac vein stent.

[0121] The length of the first transition part 30 along the circumference of the stent is less than the circumference of the radial cross section of the stent 100 where the first transition part 30 is located, and preferably, the ratio of the lengths is 2 / 3, or 1 / 2, or 1 / 3, or 1 / 4, or between 1 / 4 and 2 / 3.

[0122] Please refer to Figure 7 , the axial length d of the first transition part 30 is 6.0-9.5 mm when the stent 100 is in a non-constrained state, i.e., the stent 100 is in a fully expanded state.

[0123] Please continue to refer to Figure 5 and refer toFigure 8 The first wave-shaped rod 111 of the first part 11 comprises a plurality of wave-shaped rods with different lengths, which are arranged along the circumference of the bracket 100 and form alternating valleys and peaks along the length direction. The second wave-shaped rod 121 of the second part 12 comprises a plurality of wave-shaped rods with different lengths, which are arranged along the circumference of the bracket 100 and form alternating valleys and peaks along the length direction. The fourth wave-shaped rod 211 comprises a plurality of wave-shaped rods with different lengths, which are arranged along the circumference of the bracket 100 and form alternating valleys and peaks along the length direction. The first sub-wave-shaped rod 311 comprises a plurality of wave-shaped rods with different lengths, which are arranged along the circumference of the bracket 100 and form alternating valleys and peaks along the length direction. The a1 part of the first sub-wave-shaped rod 311, the c1 and c2 parts of the fourth wave-shaped rod 211, the wave-shaped rod f1 part of the first part 11, and the connecting rod e1 form a pentagonal structure. Compared with the quadrilateral structure, the pentagonal structure has more degrees of freedom when subjected to circumferential compression, so the bending compliance of the first sub-wave-shaped rod 311 is better than that of the front end part 10. However, since the pentagonal structure is a closed structure, its bending compliance is worse than that of the middle part 20.

[0124] Referring to Figure 8 The a1 and a2 parts of the first sub-wave-shaped rod 311 and the b1 and b2 parts of the wave-shaped rod of the second part 12 of the front end part 10 form a first quadrilateral structure, and similarly, the a2 and a3 parts of the first sub-wave-shaped rod 311 and the c3 and c4 parts of the fourth wave-shaped rod of the middle part 20 form a second quadrilateral structure. Since the first sub-wave-shaped rod 311 in the first and second quadrilateral structures is longer and thinner than the wave-shaped rod of the front end part 10, the support performance of the first and second quadrilateral structures is worse than that of the closed loop structure of the front end part, and the first and second quadrilateral structures are closed structures, so their compliance is worse than that of the middle part 20.

[0125] Please refer again to Figure 8 The b3 and b4 parts and the a3 and a4 parts form a semi-closed quadrilateral structure, the b5 and b6 parts and the a5 and a6 parts form a semi-closed quadrilateral structure, and the b7 and b8 parts and the a7 and a8 parts form a semi-closed quadrilateral structure. The c5 and c6 parts and the a4 and a5 parts form a semi-closed quadrilateral structure, and the c7 and c8 parts and the a6 and a7 parts form a semi-closed quadrilateral structure. The plurality of semi-closed quadrilateral structures have better compliance than the closed structure of the front end part 10, and stronger support than the open structure of the middle part 20. The transition of the support performance and the compliance can be realized in the axial direction of the bracket 100.

[0126] Similarly, please continue to refer to Figure 8The second sub-wave-shaped rod 312 includes a plurality of wave-shaped rods with different lengths, which are arranged in the circumferential direction of the stent 100 and form alternating valleys and peaks in the length direction. The second sub-wave-shaped rod 312 is connected with the wave-shaped rod 121 of the second part 12 on one side to form a plurality of semi-closed quadrilateral structures, and is connected with the fourth wave-shaped rod 211 of the intermediate part and / or the connecting rod on the other side to form a pentagonal structure or a semi-closed quadrilateral structure.

[0127] For example, Figure 8 As shown, the c9 and c10 parts of the fourth wave-shaped rod 211 and the a8 part of the first sub-wave-shaped rod 311, the d1 part of the second sub-wave-shaped rod 312, and the connecting rod e2 of the intermediate part form a closed pentagonal structure. In addition, the c11-c18 parts of the fourth wave-shaped rod 211 and the d2-d8 parts of the second sub-wave-shaped rod 312 form a semi-closed quadrilateral structure respectively, and the b9-b16 parts of the wave-shaped rod 121 of the second part 12 and the d2-d8 parts of the second sub-wave-shaped rod 312 form a semi-closed quadrilateral structure respectively. In the circumferential direction of the stent, the second sub-wave-shaped rod 312 is cut off at the d8 part and changes to the first wave-shaped rod 111 of the first part or the second wave-shaped rod 121 of the second part.

[0128] For further reference Figure 2 and Figure 3 The stent 100 of the embodiment of the present application can further include a second transition part 40 and a terminal part 50. The second transition part 40 constitutes a section of the pipe body of the stent 100, is adjacent to and connected with the other side of the intermediate part 20 away from the front end part 10, and the terminal part 50 constitutes another end pipe body of the stent 100, is adjacent to and connected with the other side of the second transition part 40 away from the intermediate part 20. The compliance of the second transition part 40 is greater than that of the first transition part 30, which can better meet the needs of the iliac vein stent.

[0129] The self-expanding stent 100 of the present application, the first part 11 of the front end part 10 is directly connected with the intermediate part 20, which can realize the rapid transition of the stent in the axial direction, provide flexible changes between different performance sections of the stent, reduce the occupied area of the transition part in the stent, reduce the influence of the non-uniformly distributed support structure in the transition part on the uniform expansion performance of the stent, provide a larger effective design area of the stent, meet the clinical needs, and the second part 12 is connected with the intermediate part 20 through the first transition part 30, which can realize the connection and performance change of the front end part 10 and the intermediate part 30, thereby meeting the special needs of the iliac vein stent.

[0130] The present application also provides the use of the foregoing self-expanding stent as an iliac vein stent. The present application also provides a preparation method of the foregoing self-expanding stent, comprising the steps of cutting a pipe material by laser and removing the excess part of the pipe material to obtain the hollow pipe structure of the stent, wherein the pipe material can be a shape memory or super-elastic material, preferably a super-elastic material.

[0131] After laser cutting, the excess material between the wave-shaped rods and the connecting rods is removed, and after expansion and heat treatment, a self-expanding stent with a required and determined diameter in a free expansion state is obtained.

[0132] The above description is only an embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation, or direct or indirect application in other related technical fields, which is made by using the content of the specification and drawings of the present application, is also included in the patent protection scope of the present application.

Claims

1. A lumen stent, characterized by, The stent is a hollow tube, and the stent comprises: a front end portion, which constitutes an end tube of the stent, the front end portion comprising a first portion and a second portion, the first portion and the second portion being arranged along the circumference of the stent and connected to each other; a middle portion, which constitutes a tube segment of the stent, wherein a part of the middle portion is adjacent to and directly connected to the first portion of the front end portion; and a first transition portion, which is located between the second portion of the front end portion and the middle portion, and the second portion of the front end portion is connected to the middle portion through the first transition portion; the front end portion is provided with a bevel at the other end of the tube not connected to the middle portion, the bevel has a distal end point and a proximal end point, the line between the distal end point and the proximal end point has a preset included angle with the central axis of the stent, the line divides the stent into two tube segments with a half circumference along the axial direction of the stent, and the first transition portion is located in one of the tube segments with a half circumference; the compliance of the front end portion is less than that of the first transition portion, and the compliance of the first transition portion is less than that of the middle portion.

2. The intraluminal stent of claim 1, wherein, The first portion has a first face adjacent to the middle portion in the radial direction of the tube, and the second portion has a second face adjacent to the first transition portion in the radial direction of the tube, and the second face is not coplanar with the first face.

3. The intraluminal stent of claim 2, wherein, The second face and the first face are offset to different sides of the radial cross section of the tube.

4. The intraluminal stent of claim 3, wherein, The middle portion has a third face adjacent to the first portion in the radial direction of the tube, and the third face coincides with the first face.

5. The intraluminal stent of claim 1, wherein, The length of the first transition portion along the circumference of the stent is less than the circumference of the radial cross section of the stent, and the ratio of the two lengths is 1 / 3 or 1 / 4.

6. The intraluminal stent of claim 1, wherein, In the unbound state of the stent, the axial length of the first transition portion is 6.0-9.5 mm.

7. The intraluminal stent of claim 1, wherein: the first portion comprises a plurality of first wave-shaped rods arranged along the axial direction of the stent, the first wave-shaped rods extend along the circumferential direction of the stent and have wave troughs and wave crests alternately distributed along the length direction thereof, and each two adjacent first wave-shaped rods are connected at the wave crests or wave troughs, so that the first portion has a mesh structure; the second portion comprises a plurality of second wave-shaped rods arranged along the axial direction of the stent, the second wave-shaped rods extend along the circumferential direction of the stent and have wave troughs and wave crests alternately distributed along the length direction thereof, and each two adjacent second wave-shaped rods are connected at the wave crests or wave troughs, so that the second portion has a mesh structure; the first transition portion comprises at least one third wave-shaped rod, the third wave-shaped rod extends along the circumferential direction of the stent and has wave troughs and wave crests alternately distributed along the length direction thereof; and the middle portion comprises a spiral segment, the spiral segment comprises at least one fourth wave-shaped rod extending along a spiral line in the tube circumference, the fourth wave-shaped rod has wave troughs and wave crests alternately distributed along the length direction thereof; and The first portion and the helical segment of the intermediate portion are connected at adjacent positions by forming a connection at each of the adjacent wave peaks or wave troughs, the second portion and the first transition portion are connected at adjacent positions by forming a connection at each of the adjacent wave peaks or wave troughs, and the first transition portion and the helical segment of the intermediate portion are connected at adjacent positions by forming a connection at each of the adjacent wave peaks and wave troughs.

8. The intraluminal stent of claim 7, wherein, The first portion and the intermediate portion are connected at adjacent positions by connecting a partial wave trough of the first wave-shaped rod with a partial wave peak of the fourth wave-shaped rod, the second portion and the first transition portion are connected at adjacent positions by connecting a partial wave trough of the second wave-shaped rod with a partial wave peak of the third wave-shaped rod, and the first transition portion and the intermediate portion are connected at adjacent positions by connecting a partial wave trough of the third wave-shaped rod with a partial wave peak of the fourth wave-shaped rod.

9. The intraluminal stent of claim 7, wherein, The helical segment comprises two fourth wave-shaped rods extending in a helical line, and the two fourth wave-shaped rods are connected by a connecting rod and extend in the same direction around the central axis of the stent.

10. The intraluminal stent of claim 9, wherein, The third wave-shaped rod comprises: a first sub-wave-shaped rod; and a second sub-wave-shaped rod arranged along the circumference of the stent and connected with the first sub-wave-shaped rod, wherein the first sub-wave-shaped rod and the second sub-wave-shaped rod gradually decrease or gradually increase in wave height along the circumference of the stent.

11. The intraluminal stent of claim 7, wherein, The inclination angles of the plurality of first wave-shaped rods of the first portion with respect to the central axis of the stent gradually change in sequence.

12. The intraluminal stent of claim 7, wherein, The inclination angles of the plurality of second wave-shaped rods of the second portion with respect to the central axis of the stent gradually change in sequence.

13. The intraluminal stent of claim 1, wherein, The stent further comprises: a second transition portion, which constitutes a tube segment of the stent, and is connected with the intermediate portion at a side of the intermediate portion distal to the front end portion; and a terminal portion, which constitutes another end tube segment of the stent, and is connected with the second transition portion at a side of the second transition portion distal to the intermediate portion.

14. The intraluminal stent of claim 1, wherein, The first transition portion, the second portion of the front end portion and the intermediate portion are respectively formed by different unit structures.

15. The intraluminal stent of claim 1, wherein, The tube stent is an iliac vein stent.

16. The method of claim 1-14, wherein, The steps include using a laser to cut a tube and remove excess portions of the tube to obtain the stent with the hollow tube structure. The inclination angles of the plurality of first wave-shaped rods of the first portion with respect to the central axis of the stent gradually change in sequence. The inclination angles of the plurality of second wave-shaped rods of the second portion with respect to the central axis of the stent gradually change in sequence. The stent further comprises: a second transition portion, which constitutes a tube segment of the stent, and is connected with the intermediate portion at a side of the intermediate portion distal to the front end portion; and a terminal portion, which constitutes another end tube segment of the stent, and is connected with the second transition portion at a side of the second transition portion distal to the intermediate portion. The first transition portion, the second portion of the front end portion and the intermediate portion are respectively formed by different unit structures. The tube stent is an iliac vein stent. The steps include using a laser to cut a tube and remove excess portions of the tube to obtain the stent with the hollow tube structure.

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