A closed loop bracket

Abstract

The present application relates to a closed-loop stent, which is formed by a plurality of longitudinally extending repeating units connected circumferentially, wherein the repeating units are composed of two corrugated structures and a connecting unit arranged between the two corrugated structures, and adjacent repeating units share a corrugated structure, and the two corrugated structures are respectively a first corrugated structure and a second corrugated structure, and the connecting unit is composed of a plurality of first L-shaped struts, a plurality of second L-shaped struts and a plurality of S-shaped struts, wherein one end of the first L-shaped strut is connected to the first corrugated structure, and the other end of the first L-shaped strut is connected to the S-shaped strut, one end of the second L-shaped strut is connected to the second corrugated structure, and the other end of the second L-shaped strut is connected to the S-shaped strut, and the first L-shaped strut, the second L-shaped strut and the two adjacent S-shaped struts form an eye-shaped structure, and the stent has the advantages of high metal utilization rate and low cost in the manufacturing process, adjustable axial stiffness of the stent, and small diameter after crimping.

Description

Technical Field

[0001] The present application belongs to the field of medical devices, and specifically relates to a closed-loop stent. Background Art

[0002] With the development of the times, the treatment of coronary, intracranial and other peripheral vascular diseases through the femoral artery, carotid artery and radial artery has been widely used. The extensive clinical development of minimally invasive surgery has enabled medical staff to have a deeper understanding of the diseases in various parts of the body. Due to the uncertainty of clinical patient access, for tortuous lesions or intracranial blood vessels, a smaller outer diameter of the stent delivery system can have better controllability and positioning.

[0003] Patent CN108852570 discloses a closed self-expanding unit stent, the unit stent includes a main body section and a developing marking portion connected to one end of the main body section, the main body section is a tubular structure and has a collapsed state for easy placement in a blood vessel and an expanded state for expansion in the blood vessel; the main body section includes a triangular waveform unit connected in the circumferential and axial directions of the stent in the collapsed state to form a whole, and the triangular waveform unit has an octagonal closed frame formed in the expanded state. Since the stent structure is a triangular waveform structural unit, the adjustment of the vertex angle of the triangle can adjust its flexibility, but there are certain limitations. When the stent is cut from a small diameter tube, a small vertex angle will increase the flexibility of the stent, but when the stent is expanded, due to the original tube diameter, the curvature of the triangular structure in the circumferential direction is small, which affects its wall adhesion after expansion; when the stent is cut from a large diameter tube, a small vertex angle will increase the flexibility of the stent, but when the stent is pressed and gripped, due to the large curvature of the triangular structure in the circumferential direction, the stent cannot reach a smaller outer diameter after being gripped. When it is necessary to place it in a curved blood vessel, the stent with large axial stiffness will affect the original shape of the blood vessel, reduce the curvature of the blood vessel, and easily cause intravascular stenosis at both ends of the stent. On the other hand, the stent cannot adhere to the wall normally, and a gap is formed between the large or small curved side and the blood vessel, thereby causing restenosis. In particular, because the triangular waveform unit has an octagonal closed frame structure formed in the expanded state, the diameter of the clamped state is large and the porosity is high, and the metal utilization rate is low during the stent manufacturing process.

[0004] Patent US 6,960,228 discloses a closed-loop stent structure that can be used for intracranial aneurysm auxiliary coils, and its main structure is composed of two forms of units repeatedly arranged. However, in the compressed state, there is a certain gap between the stent rods, and the metal utilization rate is low during the stent manufacturing process, which increases the manufacturing cost. Summary of the invention

[0005] In view of the limitations of the prior art, the purpose of this application is to provide a closed-loop stent made by laser cutting. This stent structure solves the problems of the existing stents having high axial stiffness, large diameter after compression and gripping, poor wall adhesion and change in blood vessel direction when treating tortuous and complex vascular lesions. It has the advantages of high metal utilization and low cost in the manufacturing process, adjustable axial stiffness of the stent and small diameter after compression and gripping.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] A closed-loop stent is formed by circumferentially connecting a plurality of longitudinally extending repeating units, wherein the repeating units are composed of two corrugated structures and a connecting unit arranged between the two corrugated structures, and adjacent repeating units share a corrugated structure, and the two corrugated structures are respectively a first corrugated structure and a second corrugated structure, and the connecting unit is composed of a plurality of first L-shaped struts, a plurality of second L-shaped struts and a plurality of S-shaped struts, wherein one end of the first L-shaped strut is connected to the first corrugated structure, and the other end of the first L-shaped strut is connected to the S-shaped strut, one end of the second L-shaped strut is connected to the second corrugated structure, and the other end of the second L-shaped strut is connected to the S-shaped strut, and the first L-shaped strut, the second L-shaped strut and two adjacent S-shaped struts form an eye-shaped structure.

[0008] The purpose of the present invention can be further achieved by the following technical solutions:

[0009] In one embodiment, the first corrugated structure and the second corrugated structure are sinusoidal waveforms, and the crests of the first corrugated structure and the crests of the second corrugated structure are on the same circumference.

[0010] In one embodiment, the first L-shaped support rod consists of a long rod segment and a short rod segment, and one end of the long rod segment of the first L-shaped support rod is connected to the first corrugated structure; the second L-shaped support rod consists of a long rod segment and a short rod segment, and one end of the long rod segment of the second L-shaped support rod is connected to the second corrugated structure.

[0011] In a preferred embodiment, the long rod sections of the plurality of first L-shaped supporting rods are parallel to each other.

[0012] In a preferred embodiment, the long rod sections of the plurality of second L-shaped supporting rods are parallel to each other.

[0013] In a preferred embodiment, when the long rod section of the first L-shaped support rod and the long rod section of the second L-shaped support rod are located on the same straight line, one end of the short rod section of the first L-shaped support rod and one end of the short rod section of the second L-shaped support rod are connected to the same S-shaped support rod.

[0014] In a more preferred embodiment, one end of the short rod segment of the first L-shaped support rod and one end of the short rod segment of the second L-shaped support rod are connected to the middle part of the same S-shaped support rod, and the two ends of the S-shaped support rod are respectively connected to the long rod segment of the first L-shaped support rod and the long rod segment of the second L-shaped support rod.

[0015] In a more preferred embodiment, two ends of the S-shaped support rod are respectively connected to the middle of the long rod section of the first L-shaped support rod and the long rod section of the second L-shaped support rod.

[0016] In a more preferred embodiment, the lengths of the first L-shaped support rod and the second L-shaped support rod are equal, and the length of the upper half of the eye-shaped structure is equal to the length of the lower half thereof.

[0017] In one embodiment, the highest point and the lowest point of the first corrugated structure and the second corrugated structure are respectively referred to as a crest and a trough, and a line connecting the crests of the first corrugated structure is parallel to the axis of the closed-loop stent.

[0018] In a preferred embodiment, the long rod section of the first L-shaped support rod and the long rod section of the second L-shaped support rod are parallel to each other.

[0019] In one embodiment, the S-shaped support rod is composed of a first curved section and a second curved section located at both ends and a straight section located in the middle, one end of the short rod section of the first L-shaped support rod and one end of the short rod section of the second L-shaped support rod are respectively connected to the end positions of the straight section of the same S-shaped support rod, one end of the first curved section of the S-shaped support rod is respectively connected to the long rod section of the first L-shaped support rod, and one end of the second curved section is connected to the long rod section of the second L-shaped support rod.

[0020] In a preferred embodiment, the end of the first curved section of the S-shaped support rod is connected to the connection between the long rod section and the short rod section of the first L-shaped support rod, and the end of the second curved section of the S-shaped support rod is connected to the connection between the long rod section and the short rod section of the second L-shaped support rod.

[0021] In one embodiment, the highest point and the lowest point of the first corrugated structure and the second corrugated structure are respectively referred to as a crest and a trough, and a line connecting the crests of the first corrugated structure forms an angle with the axis of the closed-loop stent.

[0022] In one embodiment, the ends of the S-shaped support rods at both ends of the closed-loop support extend outward and are respectively connected to the extension lines of the ends of the first corrugated structure or the second corrugated structure to form the end structure of the closed-loop support.

[0023] In a preferred embodiment, the end structure is in an arc shape, or the end structure is in a square shape.

[0024] In a preferred embodiment, a development mark is provided on the end structure.

[0025] In a preferred embodiment, an extension section is provided at the distal end of the end structure, and a hole is provided on the extension section.

[0026] In a preferred embodiment, the development mark is disposed in the hole, and the development mark includes but is not limited to one or more materials selected from the group consisting of platinum-iridium, platinum-tungsten, tantalum, and gold.

[0027] In a preferred embodiment, a sawtooth structure is provided on the rods on one side or both sides of the end structure, and a developing mark is provided on the sawtooth structure.

[0028] In a preferred embodiment, a dog-bone-shaped structure is provided on the rods on one side or both sides of the end structure, and a development mark is provided on the dog-bone-shaped structure.

[0029] In a preferred embodiment, a sawtooth-shaped and dog-bone-shaped combined structure is provided on the rods on one side or both sides of the end structure, and a developing mark is provided on the sawtooth-shaped and dog-bone-shaped combined structure.

[0030] In a preferred embodiment, the developing mark is in the form of a thread, and the developing mark in the form of a thread is wound around the main structure of the closed-loop stent and extends from one end of the closed-loop stent to the other end of the closed-loop stent.

[0031] In a more preferred embodiment, the material of the development mark includes but is not limited to platinum, iridium, tantalum, gold, etc.

[0032] In a preferred embodiment, an S rod is provided in the end structure of the closed-loop stent.

[0033] In one embodiment, the widths of the bars of the closed-loop stent are equal or unequal.

[0034] In one embodiment, two ends of the closed-loop support are configured to be trumpet-shaped.

[0035] In one embodiment, the closed-loop stent is an unequal diameter stent.

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] 1. The repeating unit of the closed-loop stent of the present application includes a first corrugated structure and a second corrugated structure. Since the first corrugated structure and the second corrugated structure are both curved structures, when the stent is bent, the corrugated structure on the larger curved side is elongated and the corrugated structure on the smaller curved side is compressed, thereby achieving bending of the stent, which not only avoids the occurrence of folding, but also improves the wall adhesion of the entire closed-loop stent.

[0038] 2. The closed-loop bracket of the present application is designed with a corrugated structure and a combined structure of an L-shaped rod and an S-shaped rod, so that the metal utilization rate of the entire bracket is high during laser cutting, thereby reducing costs.

[0039] 3. The short rod section of the L-shaped rod in the closed-loop stent of the present application can be connected to the middle part of the S-shaped rod, or it can be connected to the two ends of the straight rod section of the S-shaped rod according to different needs. This design makes the stiffness of the stent in the axial direction adjustable, and the diameter is small after being clamped, which can reduce the outer diameter of the conveyor and reduce the wound.

[0040] 4. The length and width of the short rod segment and the long rod segment of the L-shaped rod and the straight rod segment of the S-shaped rod in the closed-loop bracket of the present application can be adjusted according to actual applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of the three-dimensional structure of the closed-loop stent of the present invention.

[0042] Figure 2 It is a schematic diagram of the unfolded structure of the closed-loop stent of the present invention.

[0043] Figure 3 It is a schematic diagram of the structure of the repeating unit of the closed-loop stent of the present invention.

[0044] Figure 4 It is a schematic diagram of the partial structure enlargement of the repeating unit of the present invention.

[0045] Figure 5 It is a schematic diagram of the eye-shaped structure in the repeating unit of the present invention.

[0046] Figures 6a to 6d It is a schematic diagram of the end structure of the closed-loop stent of the present invention.

[0047] Figures 7a to 7i It is a schematic structural diagram of various embodiments of the end structure of the closed-loop stent of the present invention.

[0048] Figure 8 It is a schematic diagram of the unfolded structure of the closed-loop stent of the present invention.

[0049] Figure 9a and Figure 9b It is a schematic diagram of the bending state of the closed-loop stent of the present invention.

[0050] Fig.10It is a schematic diagram of the unfolded structure of the repeating unit of the closed-loop stent of the present invention.

[0051] Fig.11 It is a schematic diagram of the unfolded structure of the closed-loop stent of the present invention.

[0052] Fig.12 It is a schematic diagram of the unfolded structure of the closed-loop stent according to the second embodiment of the present invention.

[0053] Figures 13a to 13f It is a cross-sectional schematic diagram of the closed-loop stent of the present invention.

[0054] Fig.14 It is a schematic diagram of the unfolded structure of the third embodiment of the closed-loop stent of the present invention.

[0055] Fig.15 It is a schematic diagram of the unfolded structure of the fourth embodiment of the closed-loop stent of the present invention.

[0056] Fig.16 Is has Fig.15 An enlarged end view of a physical closed-loop stent in the deployed configuration is shown.

[0057] Figures 17a to 17c Schematic diagram of various implementations of removing metal parts by laser cutting. DETAILED DESCRIPTION

[0058] The technical solution of the present application and the advantages brought about by it are further described in detail below in conjunction with the accompanying drawings and specific embodiments. Among them, the components in the accompanying drawings are not necessarily drawn to scale, and the focus is on illustrating the concept of the present application.

[0059] Explanation of terms: The "proximal end" mentioned in this application refers to the end close to the surgical operator, and the "distal end" mentioned in this application refers to the end far from the surgical operator. The "L" shape or "S" shape mentioned in this application is only used to describe the support rod figuratively, and is not used to strictly limit the shape of the support rod. The long rod segment and the short rod segment of the "L"-shaped support rod can be straight lines or arcs, and the connection between the long rod segment and the short rod segment can also be chamfered to form an arc.

[0060] Embodiment 1

[0061] like Figure 1 and Figure 2 As shown, a closed-loop stent is formed by connecting a plurality of longitudinally extending repeating units 1 circumferentially, wherein the repeating unit 1 is composed of two corrugated structures 2 and a connecting unit 3 disposed between the two corrugated structures 2, and adjacent repeating units 1 share a corrugated structure 2, such as Figure 3As shown, the two corrugated structures 2 are respectively the first corrugated structure 21 and the second corrugated structure 22, and the connecting unit 3 is composed of a plurality of first L-shaped struts 31, a plurality of second L-shaped struts 32 and a plurality of S-shaped struts 33, one end of the first L-shaped strut 31 is connected to the first corrugated structure 21, the other end of the first L-shaped strut 31 is connected to the S-shaped strut 33, one end of the second L-shaped strut 32 is connected to the second corrugated structure 22, the other end of the second L-shaped strut 32 is connected to the S-shaped strut 33, and the first L-shaped strut 31, the second L-shaped strut 32 and the two adjacent S-shaped struts 33 form an eye-shaped structure 34. The above-mentioned closed-loop stent can be used to assist intracranial coils, which are made of nickel-titanium alloy. The width of the rods of the corrugated structure 2 and the connecting unit 3 are both 60 microns and the thickness is 80 microns. The closed-loop stent of the present application is designed with a combined structure of a corrugated structure, an L-shaped rod and an S-shaped rod, so that the metal utilization rate of the entire stent is high during laser cutting, thereby reducing costs.

[0062] like Figure 2 As shown, the highest point and the lowest point of the first corrugated structure 21 are respectively referred to as the crest 211 and the trough 212, the highest point and the lowest point of the second corrugated structure 22 are respectively referred to as the crest 221 and the trough 222, and the connecting line of the crest 211 of the first corrugated structure 21 and the connecting line of the crest 221 of the second corrugated structure 22 are both parallel to the axis of the closed-loop support. The first corrugated structure 21 and the second corrugated structure 21 are sinusoidal waveforms, and the crest 211 of the first corrugated structure 21 and the crest 221 of the second corrugated structure 22 are on the same circumference.

[0063] like Figure 3 and Figure 4 As shown, the first L-shaped support rod 31 is composed of a long rod segment 311 and a short rod segment 312. The long rod segments 311 of the first L-shaped support rods 31 are parallel to each other, and one end of the long rod segment 311 of the first L-shaped support rod 31 is connected to the first corrugated structure 21. The second L-shaped support rod 32 is composed of a long rod segment 321 and a short rod segment 322. The long rod segments 321 of the second L-shaped support rods 32 are parallel to each other, and one end of the long rod segment 321 of the second L-shaped support rod 32 is connected to the second corrugated structure 22. Except for the S-shaped support rod 33 located at the end of the closed-loop bracket, each S-shaped support rod 33 is connected to one end of the short rod segment 311 of a first L-shaped support rod 31 and one end of the short rod segment 321 of a second L-shaped support rod 32. In particular, when the long rod segment 311 of the first L-shaped support rod 31 and the long rod segment 321 of the second L-shaped support rod 32 are located on the same straight line, one end of the short rod segment 312 of the first L-shaped support rod 31 and one end of the short rod segment 322 of the second L-shaped support rod 32 are connected to the same S-shaped support rod 33.

[0064] In one embodiment, one end of the short rod segment 312 of the first L-shaped support rod 31 and one end of the short rod segment 322 of the second L-shaped support rod 32 are connected to the middle part of the same S-shaped support rod 33, and the two ends of the S-shaped support rod 33 are respectively connected to the long rod segment 311 of the first L-shaped support rod and the long rod segment 321 of the second L-shaped support rod 32.

[0065] In one embodiment, if Figure 4 As shown, the first L-shaped support rod 31 and the second L-shaped support rod 32 are of equal length, and the two ends of the S-shaped support rod 33 are respectively connected to the middle of the long rod section 311 of the first L-shaped support rod 31 and the long rod section 321 of the second L-shaped support rod 32, and the long rod section 311 of the first L-shaped support rod 31 and the long rod section 321 of the second L-shaped support rod 32 are parallel to each other. Figure 5 As shown, in the eye-shaped structure 34 formed by the first L-shaped support rod 31, the second L-shaped support rod 32 and the two adjacent S-shaped support rods 33, the length of the upper half of the eye-shaped structure 34 is equal to the length of the lower half, that is, the length of the upper half of the inner side of the mesh structure at the non-end of the bracket is equal to the length of the lower half.

[0066] like Figure 6a and Figure 6b As shown, the S-shaped struts 33 at both ends (proximal and distal ends) of the closed-loop stent extend toward the ends of the first corrugated structure 21 or the second corrugated structure 22, and are respectively connected to the extension lines of the ends of the first corrugated structure 21 or the second corrugated structure 22 to form the end structures 35 of the closed-loop stent. Figure 6c As shown, the top of the end structure 35 is an arc shape 351; or Figure 6d As shown, the top end of the end structure 35 is square 352 .

[0067] like Figure 8 As shown, the repeating unit of the closed-loop stent of the present application includes a corrugated structure 2. Since the corrugated structure 2 is a curve, when the closed-loop stent is bent, as shown in FIG. Figure 9a and Figure 9b As shown, the first corrugated structure 21 on the large bend side is stretched, and the second corrugated structure 22 on the small bend side is compressed, thereby achieving the bending of the closed-loop stent and avoiding the occurrence of folding.

[0068] like Figure 7a As shown in FIG. 7i , a developing mark 36 is provided on the end structure 35 , and the developing mark 36 is made of, but not limited to, one or more materials selected from the group consisting of platinum iridium, platinum tungsten, tantalum, and gold. Figure 7a As shown, an extension section 37 is provided at the distal end of the end structure 35, and a hole 38 is provided on the extension section 37. Figure 7bAs shown, the development mark 36 is disposed in the hole 38. The shape of the hole 38 includes but is not limited to a circle, a multi-circle, an oblong, a quadrilateral and a polygon. In other embodiments, the development mark 36 is a development tube, which is riveted to the position of the hole 38, or the development tube is directly fixed to the end structure 35 (not shown). In one embodiment, as Figure 7c As shown, a sawtooth structure 353 is provided on the rods on one or both sides of the end structure 35. Figure 7d As shown, the filamentary developing mark 36 is wound in the groove of the sawtooth structure, and the material of the filamentary developing mark includes but is not limited to platinum iridium, tantalum, and gold. Figure 7e As shown, a dog bone structure 354 is provided on the rods on one or both sides of the end structure 35. Figure 7f As shown, a filamentous imaging marker 36 is wound in the middle of the dog-bone structure for use as a developer. Figure 7g As shown, a tube made of platinum-iridium, platinum-tungsten, tantalum, gold or the like can also be used as the developing mark 36. The tubular developing mark 36 is placed in the middle recessed position and fixed by riveting, welding or bonding, or a slit is cut in the tube and then cold pressed onto the bracket. Figure 7h As shown, a sawtooth-shaped and dog-bone-shaped combined structure 355 is provided on the rods on one or both sides of the end structure 35, as shown in FIG. Figure 7i As shown, the filamentary developing mark 36 can be wound around the depression of the sawtooth and the middle position of the dog-bone-shaped structure. In other embodiments, the filamentary developing mark 36 can also be wound around the main structure of the closed-loop stent and extend from one end of the closed-loop stent to the other end of the closed-loop stent, that is, one end of the developing wire is wound around the end structure 35 located at the proximal end of the closed-loop stent, and the other end of the developing wire is wound around the end structure 35 located at the distal end of the closed-loop stent. For example, a platinum-tungsten wire is used to be wound in a spiral shape on the outside of the closed-loop stent, and its two ends are respectively connected to the end structures 35 located at the two ends. In order to prevent the developing wire from falling off, when it is wound in a spiral shape on the outside of the closed-loop stent, it can pass through the stent mesh at multiple positions of the closed-loop stent. The developing mark can also be a metal coating coated on the surface of the closed-loop stent, and the metal coating can be coated on the entire surface of the stent, or partially coated. The material of the metal coating includes, but is not limited to, one or more of platinum-iridium, platinum-tungsten, tantalum, and gold. The metal coating can make the closed-loop stent develop. Of course, the closed-loop stent development method can be one or a combination of the above methods.

[0069] like Fig.10As shown, the lower right section of the first L-shaped support rod 31 and the upper right section of the S-shaped support rod 33 can also be regarded as a curve 191 that continues from the leftmost end to the rightmost end of the bracket; the upper left section of the second L-shaped support rod 32 and the lower left section of the S-shaped support rod 33 can also be regarded as a curve 192 that continues from the leftmost end to the rightmost end of the bracket. Curves 191 and 192 are similar in shape to the first corrugated structure 21 and the second corrugated structure 22, and therefore also have the ability to be compressed and stretched, which helps to improve the flexibility of the bracket. In practical applications, the lengths of the first L-shaped support rod 31, the second L-shaped support rod 32 and the S-shaped support rod 33 can be adjusted as needed, so that the radial forces at different parts of the same bracket are different, that is, the radial force of the bracket can be changed by changing the design size or changing the shape formed during heat treatment to meet different needs.

[0070] like Fig.11 As shown, the connecting line of the long rod segment of the first L-shaped support rod and the long rod segment of the second L-shaped support rod of the adjacent repeating unit and the part of the corrugated structure located between the two L-shaped support rods can extend from the upper left corner to the lower right corner, as shown in FIG. Fig.11 As shown by the heavy line 193 in the figure, the stent has a spiral structure, thereby improving the flexibility of the stent.

[0071] The closed-loop stent can be made into a drug-loaded stent. For example, in one embodiment, a drug coating is applied on the surface of the closed-loop stent; in another embodiment, a microporous structure is provided on the surface of the closed-loop stent, and drugs can be stored in the microporous structure; in yet another embodiment, blind grooves are provided on the struts and / or corrugated structures of the closed-loop stent, and drugs can be stored in the blind grooves.

[0072] The closed-loop stent is a degradable stent or a non-degradable stent, or a partially degradable stent. For example, the closed-loop stent is a non-degradable stent made of nickel-titanium alloy, cobalt-chromium alloy or stainless steel; or the closed-loop stent is a degradable stent made of polylactic acid, zinc alloy, magnesium alloy or iron alloy; or the closed-loop stent is a partially degradable stent with a skeleton made of non-degradable nickel-titanium alloy, cobalt-chromium alloy or stainless steel and a degradable outer structure made of polylactic acid, zinc alloy, magnesium alloy or iron alloy.

[0073] In one embodiment, the closed-loop stent is formed by cutting a pipe. Preferably, the closed-loop stent is formed by using a small diameter (e.g., 0.6 mm) pipe, which is cut by laser and then heat-treated and surface-treated. In another embodiment, the closed-loop stent is formed by 3D printing additive manufacturing technology.

[0074] In one embodiment, the closed-loop stent can be coated and used as a coated stent.

[0075] Embodiment 2

[0076] The main structure of this embodiment is basically the same as that of the first embodiment, and is formed by a plurality of longitudinally extending repeating units 1 connected circumferentially, wherein the repeating unit 1 is composed of two corrugated structures and a connecting unit 3 arranged between the two corrugated structures 2, and adjacent repeating units 1 share a corrugated structure 2, and the two corrugated structures 2 are respectively a first corrugated structure 21 and a second corrugated structure 22, and the connecting unit 3 is composed of a plurality of first L-shaped support rods 31, a plurality of second L-shaped support rods 32, and a plurality of S-shaped support rods 33, wherein one end of the first L-shaped support rod 31 is connected to the first corrugated structure 21, and the other end of the first L-shaped support rod 31 is connected to the S-shaped support rod 33, one end of the second L-shaped support rod 32 is connected to the second corrugated structure 22, and the other end of the second L-shaped support rod 32 is connected to the S-shaped support rod 33, and the first L-shaped support rod 31, the second L-shaped support rod 32 and the two adjacent S-shaped support rods 33 form an eye-shaped structure 34. The difference is that: Fig.12 As shown, first, the line connecting the wave crests of the first corrugated structure 21 and the line connecting the wave crests of the second corrugated structure 22 form an angle with the axis of the closed-loop support; second, the S-shaped support rod 33 is composed of a first curved section 331 and a second curved section 333 located at both ends and a straight section 332 located in the middle, one end of the short rod section 312 of the first L-shaped support rod 31 and one end of the short rod section 322 of the second L-shaped support rod 32 are respectively connected to the end positions of the straight section 332 of the same S-shaped support rod 33, one end of the first curved section 331 is connected to the long rod section 311 of the first L-shaped support rod 31, and one end of the second curved section 333 is connected to the long rod section 321 of the second L-shaped support rod 32. In one embodiment, the end of the first curved segment 331 of the S-shaped support rod 33 is connected to the connection between the long rod segment 311 and the short rod segment 312 of the first L-shaped support rod 31, and the end of the second curved segment 333 of the S-shaped support rod 33 is connected to the connection between the long rod segment 321 and the short rod segment 322 of the second L-shaped support rod 32.

[0077] The closed-loop stent of this embodiment is made of a tube with a diameter of 2.0 mm through laser cutting and subsequent processing, and can be used as a coronary stent. Its material is a degradable iron alloy. The width of the first corrugated structure 21 and the second corrugated structure 22 and the L-shaped struts and the S-shaped struts are all 100 microns, and the thickness is 75 microns. The surface of the closed-loop stent is coated with a degradable polylactic acid coating, and the coating contains drugs to prevent restenosis.

[0078] In other embodiments, the closed-loop stent is a self-expanding stent made of nickel-titanium alloy, such as Fig.13a As shown, the closed-loop stent is cylindrical; in some other embodiments, as Fig.13b and 13cAs shown, the closed-loop stent is an unequal diameter stent; in other embodiments, as Figures 13d to 13f As shown, the two ends of the closed-loop bracket are configured to be flared, such as Fig.13d As shown, the two ends of the closed-loop bracket are in a conical flare shape, such as Fig.13f As shown, the two ends of the closed-loop bracket are in the shape of circular arc bell mouths. Fig.13e As shown, the closed-loop bracket is an unequal diameter bracket, and arc-shaped bell mouths are arranged at both ends.

[0079] Embodiment 3

[0080] The main structure of this embodiment is basically the same as that of the first embodiment, and is formed by a plurality of longitudinally extending repeating units 1 connected circumferentially, wherein the repeating unit 1 is composed of two corrugated structures 2 and a connecting unit 3 arranged between the two corrugated structures 2, and adjacent repeating units 1 share a corrugated structure 2, and the two corrugated structures 2 are respectively a first corrugated structure 21 and a second corrugated structure 22, and the connecting unit 3 is composed of a plurality of first L-shaped support rods 31, a plurality of second L-shaped support rods 32 and a plurality of S-shaped support rods 33, wherein one end of the first L-shaped support rod 31 is connected to the first corrugated structure 21, and the other end of the first L-shaped support rod 31 is connected to the S-shaped support rod 33, one end of the second L-shaped support rod 32 is connected to the second corrugated structure 22, and the other end of the second L-shaped support rod 32 is connected to the S-shaped support rod 33, and the first L-shaped support rod 31, the second L-shaped support rod 32 and the two adjacent S-shaped support rods 33 form an eye-shaped structure 34. The difference is that: Fig.14 As shown, the directions of the first L-shaped support rod 31 and the second L-shaped support rod 32 are mirror-symmetrical to those of the first embodiment, and the opening direction of the S-shaped support rod is also mirror-symmetrical to that of the S-shaped support rod in the first embodiment.

[0081] The closed-loop stent of this embodiment is made of a tube with a diameter of 2.0 mm through laser cutting and subsequent processing, and can be used as a coronary stent. Its material is a degradable iron alloy. The width of the corrugated structure 2 and the L-shaped struts and the S-shaped struts are all 100 microns and the thickness is 75 microns. The surface of the closed-loop stent is coated with a degradable polylactic acid coating, and the coating contains drugs to prevent restenosis.

[0082] In the above embodiment, the short rod section 312 and the long rod section 311 constituting the first L-shaped support rod 31 may be as follows: Fig.14The straight line shown can also be an arc line, and the connection between the short rod segment 312 and the long rod segment 311 is chamfered, so that the entire first L-shaped support rod 31 is a smooth arc structure. Similarly, the short rod segment 322 and the long rod segment 321 that constitute the second L-shaped support rod 32 can also be arc lines, and even the straight segment 332 of the S-shaped support rod 33 can also be set to have a certain curvature, so that the grid unit of the entire closed-loop bracket is smoother and has no protruding structure. The straight line described in this application is only for the convenience of description, and does not limit the long rod segment or the short rod segment of the support rod to be a straight line.

[0083] Embodiment 4

[0084] The main structure of this embodiment is basically the same as that of the first embodiment, and is formed by a plurality of longitudinally extending repeating units 1 connected circumferentially, wherein the repeating unit 1 is composed of two corrugated structures 2 and a connecting unit 3 arranged between the two corrugated structures 2, and adjacent repeating units 1 share a corrugated structure 2, and the two corrugated structures 2 are respectively a first corrugated structure 21 and a second corrugated structure 22, and the connecting unit 3 is composed of a plurality of first L-shaped support rods 31, a plurality of second L-shaped support rods 32 and a plurality of S-shaped support rods 33, wherein one end of the first L-shaped support rod 31 is connected to the first corrugated structure 21, and the other end of the first L-shaped support rod 31 is connected to the S-shaped support rod 33, one end of the second L-shaped support rod 32 is connected to the second corrugated structure 22, and the other end of the second L-shaped support rod 32 is connected to the S-shaped support rod 33, and the first L-shaped support rod 31, the second L-shaped support rod 32 and the two adjacent S-shaped support rods 33 form an eye-shaped structure 34. The difference is that: Fig.15 As shown, an S rod 356 is provided in the end structure of the closed-loop support. Fig.16 This is a partial picture of the closed-loop bracket after laser cutting and heat treatment. Fig.16 As shown, the provision of the S rod 356 increases the grid density at the end of the closed-loop stent, thereby improving the radial supporting force at both ends of the closed-loop stent.

[0085] The length and width of the L-shaped rod and the S-shaped rod in the closed-loop bracket of the present application can be adjusted by removing a portion of the metal by laser cutting. Fig.17a , Fig.17b and Fig.17c The area enclosed by the middle contour is the area where the metal is removed. Fig.17a As shown, the length of the contour line of the upper half of the region is equal to the length of the contour line of the lower half. In other embodiments, the length of the contour line of the upper half of the removed region may be different from the length of the contour line of the lower half. Fig.17b and 17cAs shown, when the removal area is widened, the width of the rod corresponding to the position is reduced, so that the hollowing amount at this position is different from that at other positions. By adjusting the removal area in this way, the length and width of the L-shaped rod and the S-shaped rod can be adjusted, thereby adjusting the radial force, compliance shape and mesh size of the closed-loop stent at different positions, so that the closed-loop stent has different performances at different positions to adapt to complex usage scenarios.

[0086] It should be noted that the above embodiments are only partial examples. Whether the crests and troughs of the waveform structure are connected in correspondence, or whether the crests and troughs are staggered, the number and distribution of the curved rods in the mesh unit, the structural type of the curved rods, and the connection positions of the curved rods can be cross-combined and exist in the same or different support structures.

[0087] The above detailed description of the present invention is intended to enable persons familiar with the art to understand the contents of the present invention and implement them. It does not limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A closed-loop stent, comprising a plurality of longitudinally extending repeating units connected circumferentially, characterized in that: The repeating unit is composed of two corrugated structures and a connecting unit arranged between the two corrugated structures. Adjacent repeating units share a corrugated structure. The two corrugated structures are respectively a first corrugated structure and a second corrugated structure. The connecting unit is composed of a plurality of first L-shaped support rods, a plurality of second L-shaped support rods and a plurality of S-shaped support rods. One end of the first L-shaped support rod is connected to the first corrugated structure, and the other end of the first L-shaped support rod is connected to the S-shaped support rod. One end of the second L-shaped support rod is connected to the second corrugated structure, and the other end of the second L-shaped support rod is connected to the S-shaped support rod. The first L-shaped support rod, the second L-shaped support rod and the second L-shaped support rod are connected to the S-shaped support rod. The support rod and two adjacent S-shaped support rods form an eye-shaped structure, the first L-shaped support rod is composed of a long rod segment and a short rod segment, one end of the long rod segment of the first L-shaped support rod is connected to the first corrugated structure; the second L-shaped support rod is composed of a long rod segment and a short rod segment, one end of the long rod segment of the second L-shaped support rod is connected to the second corrugated structure, one end of the short rod segment of the first L-shaped support rod and one end of the short rod segment of the second L-shaped support rod are connected to the middle part of the same S-shaped support rod, the two ends of the S-shaped support rod are respectively connected to the long rod segment of the first L-shaped support rod and the long rod segment of the second L-shaped support rod, and the closed-loop support is an unequal diameter support.

2. The closed-loop stent according to claim 1, characterized in that: The first corrugated structure and the second corrugated structure are sinusoidal waveforms, and the crests of the first corrugated structure and the crests of the second corrugated structure are on the same circumference.

3. The closed-loop stent according to claim 1, characterized in that: The long rod sections of the plurality of first L-shaped supporting rods are parallel to each other, and the long rod sections of the plurality of second L-shaped supporting rods are parallel to each other.

4. The closed-loop stent according to claim 1, characterized in that: When the long rod section of the first L-shaped support rod and the long rod section of the second L-shaped support rod are located on the same straight line, one end of the short rod section of the first L-shaped support rod and one end of the short rod section of the second L-shaped support rod are connected to the same S-shaped support rod.

5. The closed-loop stent according to claim 1, characterized in that: The highest point and the lowest point of the first corrugated structure and the second corrugated structure are respectively called a crest and a trough, and a connecting line of the crests of the first corrugated structure is parallel to the axis of the closed-loop support.

6. The closed-loop stent according to claim 1, characterized in that: The highest point and the lowest point of the first corrugated structure and the second corrugated structure are respectively called the crest and the trough, and the connecting line of the crests of the first corrugated structure forms an angle with the axis of the closed-loop support.

7. The closed-loop stent according to claim 6, characterized in that: The S-shaped support rod is composed of a first curved section and a second curved section located at both ends and a straight section located in the middle; one end of the short rod section of the first L-shaped support rod and one end of the short rod section of the second L-shaped support rod are respectively connected to the end positions of the straight section of the same S-shaped support rod; one end of the first curved section is connected to the long rod section of the first L-shaped support rod; and one end of the second curved section is connected to the long rod section of the second L-shaped support rod.

8. The closed-loop stent according to claim 1, characterized in that: The ends of the S-shaped support rods at both ends of the closed-loop support extend outward and are respectively connected to the extension lines of the ends of the first corrugated structure or the second corrugated structure to form the end structure of the closed-loop support.

9. The closed-loop stent according to claim 8, characterized in that: A sawtooth structure, a dog-bone structure or a combination of sawtooth and dog-bone structures is arranged on the rods on one side or both sides of the end structure, and a developing device is arranged on the sawtooth structure, the dog-bone structure or the combination of sawtooth and dog-bone structures.

10. The closed-loop stent according to claim 8, characterized in that: An S rod is arranged in the end structure of the closed-loop support.

11. The closed-loop stent according to claim 1, characterized in that: Both ends of the closed-loop bracket are configured to be in a trumpet shape.

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