Drug-eluting stents

Abstract

The present invention discloses a drug eluting stent, comprising a stent body and a plurality of thorn-shaped members, wherein the stent body has a radially compressible contracted state and a radially self-expanding expanded state for supporting a blood vessel, the plurality of thorn-shaped members are arranged on the outer surface of the stent body and coated with a drug coating for inhibiting restenosis of the blood vessel, and are configured to protrude from the outer surface of the stent body toward the outside of the stent body when the stent body switches from the contracted state to the expanded state to penetrate calcified lesions on the inner wall of the blood vessel, each thorn-shaped member comprises a spike segment, and the spike segment comprises at least a first segment and a second segment connected together at a root, the first segment and the second segment being configured to fit together to form a compact structure in a natural state, and to be elastically deformed and separated relative to the root when subjected to a reverse force from the calcified lesion, so as to achieve penetration of the calcified lesion at a larger angle, reduce the risk of slippage, improve penetration efficiency, and thereby enhance the effect of inhibiting restenosis of the blood vessel.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a drug eluting stent. Background Art

[0002] Drug-eluting stents are currently widely used to treat vascular stenosis. To effectively release drugs at the targeted site of vascular lesions, some stent designs incorporate spikes to deliver the drug directly into the deep tissues of the vessel wall. For example, Chinese patent CN113599032A discloses a stent system with a spike structure to enhance local drug delivery efficiency and therapeutic efficacy.

[0003] However, the spike structure in the prior art mostly adopts an integral structure, and its shape remains fixed during the expansion process of the stent, resulting in the spikes being able to penetrate the inner wall of the blood vessel only in a predetermined manner, with a limited penetration area, making it difficult to cover a larger range of lesion areas. This limitation is particularly evident in pathological conditions with high hardness and irregular surfaces, such as calcified lesions. The lack of penetration range not only reduces the uniformity of drug distribution in the diseased tissue, but also affects the kinetics of local drug release, thereby limiting the stent's potential for treating complex lesions. In addition, the integral spikes lack structural deformation capabilities, and are prone to slippage or deflection when encountering hard or uneven calcified areas, further weakening their penetration ability and penetration depth. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a drug-eluting stent in response to the above-mentioned defects in the prior art, aiming to enhance the effect of inhibiting vascular restenosis and improve the overall therapeutic performance of the stent.

[0005] According to the present invention, a drug-eluting stent is provided, comprising a stent body and a plurality of thorn-like members, wherein the stent body has a radially compressible contracted state and a radially self-expanding expanded state for supporting a blood vessel, the plurality of thorn-like members being arranged on the outer surface of the stent body and coated with a drug coating for inhibiting restenosis of the blood vessel, and being configured to protrude from the outer surface of the stent body toward the outside of the stent body to penetrate calcified lesions on the inner wall of the blood vessel when the stent body switches from the contracted state to the expanded state, each thorn-like member comprising a spike segment, which is the portion of the thorn-like member away from the outer surface of the stent body, the spike segment comprising at least a first segment and a second segment connected together at a root, the first segment and the second segment being configured to fit together to form a compact structure in a natural state, and to be elastically deformed and separated relative to the root when subjected to a reverse force from the calcified lesion, so as to achieve penetration of the calcified lesion at a larger angle.

[0006] Furthermore, the first section and the second section are integrally formed on the outer surface of the stent body by a laser cutting process, and a predetermined gap is left between the first section and the second section to allow the two to be separated along the root after being subjected to the reverse force of the self-calcified lesion.

[0007] Furthermore, the first section and the second section are fitted together to form a triangle in a natural state.

[0008] Furthermore, the spike segment further includes a third segment. The first segment and the third segment are arranged on both sides of the second segment and can deviate from the second segment in opposite directions when subjected to a reverse force from a calcified lesion.

[0009] Furthermore, the first section, the second section and the third section are fitted together to form a triangle in a natural state.

[0010] Furthermore, the tip of the second segment is more protruding than the tips of the first segment and the third segment, so that when piercing the calcified lesion, the second segment is the first to contact and penetrate the calcified lesion.

[0011] Furthermore, the size of the second section is larger than that of the first section and the third section, and the first section and the third section are symmetrically arranged on both sides of the second section.

[0012] Furthermore, a drug loading groove is provided on the second section, and a drug loading space is formed inside the drug loading groove and is filled with a drug coating.

[0013] Furthermore, each thorn-shaped member further includes a deformation segment arranged between the stent body and the spike segment, and the root of each segment on the spike segment is connected to a different position of the deformation segment away from one end of the stent body.

[0014] Furthermore, a slotted structure is provided on the deformation section to form a spring structure.

[0015] Compared with the prior art, the spike segment of the thorn-like component of the present invention adopts a split structure consisting of a first segment and a second segment connected at the root. The split structure remains in close contact in a natural state, forming a compact shape, which is conducive to the smooth delivery of the stent. During the insertion process, the first segment and the second segment can be relatively expanded under the action of external force, thereby increasing the insertion angle and contact area, significantly improving the coverage range and insertion depth of the calcified lesion area, reducing the risk of slippage, and improving the insertion efficiency, thereby enhancing the effect of inhibiting vascular restenosis and improving the overall therapeutic performance of the stent. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] A more complete understanding of the present invention and its attendant advantages and features will be more readily obtained by referring to the following detailed description taken in conjunction with the accompanying drawings.

[0017] Figure 1It is a schematic diagram of the overall structure of an embodiment of the present invention.

[0018] Figure 2 yes Figure 1 Enlarged view of part A in the middle.

[0019] Figure 3 Schematic diagram of the structure of the spike section in a natural state according to an embodiment of the present invention.

[0020] In the accompanying drawings: 10 is the stent body; 20 is the thorn-shaped component, 21 is the fixed section, 22 is the deformation section, 23 is the spike section, 231 is the first section, 232 is the second section, and 233 is the third section; 30 is the slotted structure, 31 is the first group of slots, and 32 is the second group of slots; 40 is the drug loading slot.

[0021] It should be noted that the accompanying drawings are intended to illustrate the present invention, not to limit it. Note that the accompanying drawings showing structures may not be drawn to scale. Furthermore, in the accompanying drawings, identical or similar elements are labeled with identical or similar reference numerals. DETAILED DESCRIPTION

[0022] In order to make the contents of the present invention clearer and easier to understand, the contents of the present invention are described in detail below with reference to specific embodiments and drawings.

[0023] The "proximal end" and "distal end" referred to in the present invention should be understood as observed from the direction of the attending physician. The "proximal end" refers to the end close to the attending physician, which corresponds to the "left end" referred to in the reference drawing, and the "distal end" refers to the end away from the attending physician, which corresponds to the "right end" referred to in the reference drawing.

[0024] like Figures 1 to 3 As shown, the drug-eluting stent of this embodiment includes a stent body 10 and a plurality of thorn-like members 20. The stent body 10 is a hollow tubular structure, which is made of a metal tube such as a nickel-titanium tube by laser engraving and heat treatment. Several grids are formed on the surface, and it has a contracted state of radial contraction and an expanded state of radial self-expansion to support the blood vessel. Not only does it ensure the flexibility and strength of the stent, but it also ensures that it can be smoothly deployed and stably support the blood vessel wall in the body. The choice of nickel-titanium alloy material enables the stent to have good biocompatibility and shape memory function, and can maintain its structural stability under different environments. It should be noted that in actual use, this embodiment often requires the use of balloon filling to push the stent body 10 to expand so that the plurality of thorn-like members 20 can penetrate the lesion.

[0025] Multiple thorn-like members 20 are circumferentially arranged on the outer surface of the stent body 10. These thorn-like members 20 and the stent body 10 are integrally formed by laser engraving and then heat-setting, ensuring structural consistency and stability. After integral molding, the entire stent is coated with a drug coating that inhibits restenosis. This drug coating can be a drug commonly used in the prior art, such as rapamycin, which will not be described here. This drug coating design helps to improve drug utilization and achieve deep drug delivery to the lesion area. As an anti-proliferative drug, the drug coating can effectively inhibit the excessive proliferation of smooth muscle cells, thereby reducing the risk of restenosis.

[0026] When the stent body 10 switches from a contracted to an expanded state, multiple spike-like members 20 protrude from the outer surface of the stent body 10 toward the outside of the stent body 10 to penetrate calcified lesions on the inner wall of the blood vessel, thereby achieving deep drug delivery to the calcified lesion area. The spike-like members 20 have an overall sheet-like structure and gradually deviate from the stent body 10 from the proximal end to the distal end when the stent body 10 is in the expanded state. This facilitates the safe removal of the entire drug-eluting stent from the human body from the distal end to the proximal end. Each spike-like member 20 has an elastically deformable portion and is configured to adaptively deform according to the thickness of the calcified lesion it contacts, effectively penetrating irregular calcified lesions and promoting drug release. Even in calcified lesions with large thickness variations, all spike-like members 20 maintain excellent penetration and structural stability, ensuring uniform drug distribution within the target lesion area, significantly improving drug utilization and therapeutic efficacy.

[0027] See also Figure 2 Each thorn-shaped member 20 includes a fixed segment 21, a deformable segment 22, and a spike segment 23, which are connected in sequence. The spike segment 23 is the portion of the thorn-shaped member 20 that is away from the outer surface of the stent body 10. The fixed segment 21 is connected to the outer surface of the stent body 10 and is located on the outer circumference of the stent body 10. The deformable segment 22 and the spike segment 23 are tilted outward relative to the fixed segment 21, so that when the stent body 10 is in the expanded state, the deformable segment 22 and the spike segment 23 can gradually deviate from the stent body 10 from the proximal end to the distal end. The deformable segment 22 is connected between the fixed segment 21 and the spike segment 23, forming a portion of the thorn-shaped member 20 that can undergo elastic deformation. This allows the spike segment 23 to contact calcified lesions of different thicknesses and then adaptively deform, thereby enabling the spike segment 23 to effectively penetrate irregular calcified lesions and promote drug release.

[0028] Combine Figure 3To enhance the elastic deformation capability of the thorn-shaped member 20, the deformable section 22 is provided with slotted structures 30, creating a spring-like structure. These slotted structures 30 are located on either side of the deformable section 22 along its length, with the fixed section 21 and spike section 23 connected to either end of the deformable section 22. The slotted structure 30 comprises at least a first set of slots 31 and a second set of slots 32. The first set of slots 31 extends through one side of the deformable section 22, while the second set of slots 32 extends through the other side. The first and second sets of slots 31, 32 are staggered, forming at least one arched region within the slotted structure 30, thereby simulating the effect of a spring. This design not only improves the elastic response capability of the thorn-shaped member 20 but also enhances its adaptability to lesions of varying thicknesses. The design of the slotted structure 30 is similar to a spring mechanism. When encountering a thicker calcified lesion, the slotted structure 30 will be compressed and deformed, while when encountering a thinner lesion, it will bend slightly or not bend at all, thereby ensuring that each thorn-like member 20 can effectively penetrate the diseased tissue. Each thorn-like member 20 is relatively independent and does not affect each other.

[0029] The inner surface of the slotted structure 30 is also coated with a drug coating. In other words, the first and second sets of slots 31, 32 not only act as springs but also house the drug coating. This not only increases the drug loading capacity of the entire spike-shaped member 20 but also ensures that the drug is rapidly released upon contact with the diseased tissue, achieving optimal therapeutic effects. This multi-layer drug coating design allows for more even distribution of the drug throughout the lesion area, significantly improving drug utilization and therapeutic efficacy. Furthermore, the presence of the slotted structure 30 allows the drug to be released at different locations within the spike-shaped member 20, further increasing the drug's penetration depth and coverage.

[0030] The spike section 23 is a split structure and includes a first section 231, a second section 232, and a third section 233 connected together at the root. The roots of the first section 231, the second section 232, and the third section 233 are connected to different positions of the end of the deformation section 22 away from the stent body 10, and are configured so that the three sections fit together to form a compact structure, such as a triangle, in a natural state. For details, see Figure 3 This design not only allows the spike segment 23 to maintain a compact shape when not under stress, which is beneficial to the smooth delivery of the stent, but also allows the three segments to undergo elastic deformation and separate relative to the root when subjected to a reverse force from the calcified lesion, thereby increasing the insertion angle and contact area, significantly improving the coverage and insertion depth of the calcified lesion area, reducing the risk of slippage, and improving the insertion efficiency, thereby enhancing the effect of inhibiting vascular restenosis and improving the overall therapeutic performance of the stent.

[0031] Specifically, the first section 231, the second section 232 and the third section 233 are integrally formed on the outer surface of the stent body 10 by laser cutting. The first section 231 and the third section 233 are symmetrically arranged on both sides of the second section 232, and can deviate from the second section 232 in opposite directions when subjected to a reverse force from the calcified lesion. Figure 1 and Figure 2 . The tip of the second section 232 is more prominent than the tips of the first section 231 and the third section 233, so that when puncturing a calcified lesion, the second section 232 is the first to contact and penetrate the calcified lesion to act as an anchor. In addition, the size of the second section 232 is larger than the size of the first section 231 and the third section 233 to strengthen the anchoring effect. Since the size of the second section 232 is relatively large, a drug loading groove 40 is provided on the second section 232. The drug loading groove 40 is not through, and a drug loading space is formed inside the drug loading groove 40 and is filled with a drug coating, further improving the therapeutic effect.

[0032] To better understand the design flexibility of the spike segment 23, it is understood that the spike segment 23 may comprise only a first segment and a second segment connected at the base, or may comprise more segments depending on practical needs. As long as the spike segment comprises at least the first and second segments connected at the base, forming a split structure, and a predetermined gap is left between the first and second segments to allow them to separate along the base after being subjected to the reverse force from the calcified lesion, thereby achieving a wider angle of penetration into the calcified lesion, this flexible design can be adjusted to meet different clinical needs to achieve the optimal therapeutic effect.

[0033] It is understood that although the present invention has been disclosed above with reference to preferred embodiments, the above embodiments are not intended to limit the present invention. For any person skilled in the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or to modify it into an equivalent embodiment with equivalent changes. Therefore, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A drug-eluting stent comprising a stent body and a plurality of thorn-like members, wherein the stent body has a contracted state in which it is radially compressible and an expanded state in which it radially self-expands to support a blood vessel, the plurality of thorn-like members being disposed on the outer surface of the stent body and coated with a drug coating for inhibiting restenosis of the blood vessel, and being configured to protrude from the outer surface of the stent body toward the outside of the stent body to penetrate calcified lesions on the inner wall of the blood vessel when the stent body switches from the contracted state to the expanded state, characterized in that: Each thorn-shaped member includes a spike segment, which is the part of the thorn-shaped member away from the outer surface of the stent body. The spike segment includes at least a first segment and a second segment connected together at the root. The first segment and the second segment are constructed so that they fit together to form a compact structure in a natural state. When subjected to a reverse force from the calcified lesion, the first segment and the second segment can undergo elastic deformation relative to the root and separate to achieve penetration into the calcified lesion at a larger angle.

2. The drug-eluting stent according to claim 1, wherein: The first section and the second section are integrally formed on the outer surface of the stent body by a laser cutting process, and a predetermined gap is left between the first section and the second section to allow the two to be separated along the root after being subjected to the reverse force of the self-calcified lesion.

3. The drug-eluting stent according to claim 1, wherein: The first section and the second section are attached to form a triangle shape in a natural state.

4. The drug-eluting stent according to claim 1, wherein: The spike segment further includes a third segment. The first segment and the third segment are arranged on both sides of the second segment and can deviate from the second segment in opposite directions when subjected to a reverse force from a calcified lesion.

5. The drug-eluting stent according to claim 4, characterized in that: The first section, the second section and the third section are fitted together to form a triangle in a natural state.

6. The drug-eluting stent according to claim 4, characterized in that: The tip of the second segment is more protruding than the tips of the first segment and the third segment, so that when piercing a calcified lesion, the second segment is the first to contact and penetrate the calcified lesion.

7. The drug-eluting stent according to claim 4, characterized in that: The size of the second section is larger than that of the first section and the third section, and the first section and the third section are symmetrically arranged on both sides of the second section.

8. The drug-eluting stent according to claim 4, characterized in that: The second section is provided with a drug loading groove, wherein a drug loading space is formed inside the drug loading groove and is filled with a drug coating.

9. The drug-eluting stent according to claim 1, wherein: Each thorn-shaped component further comprises a deformation section arranged between the support body and the spike section, and the root of each section of the spike section is connected to different positions of the deformation section away from one end of the support body.

10. The drug-eluting stent according to claim 9, characterized in that: The deformation section is provided with a slotted structure to form a spring structure.

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