Drug-eluting stents

Abstract

The present invention discloses a drug-eluting stent, comprising a stent body and a plurality of thorn-shaped members. 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. The plurality of thorn-shaped members are 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-shaped member has a portion that can undergo elastic deformation and is configured to adaptively deform according to the thickness of the calcified lesion it contacts, so as to achieve effective penetration of irregular calcified lesions and promote drug release, thereby ensuring that the drug can be evenly distributed in the target lesion area, significantly improving drug utilization and therapeutic effect.

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] In the interventional treatment of vascular stenosis, drug-eluting stents have gradually replaced the relatively simple bare metal stents because of their ability to effectively inhibit postoperative restenosis, becoming the mainstream treatment method in clinical applications. This type of stent is coated with a drug coating on its surface that inhibits vascular restenosis. This drug coating can be slowly released into the blood vessel wall to prevent excessive proliferation of smooth muscle cells, thereby significantly reducing the incidence of restenosis. However, traditional drug-eluting stents still face certain challenges when treating stenotic lesions accompanied by calcified lesions. Because calcified lesions are hard and have poor permeability, they may hinder the effective diffusion of drugs from the stent coating to the deep blood vessel wall, affecting the treatment effect.

[0003] To address these issues, Chinese patent CN113599032A adds multiple, uniformly-length microspikes to a conventional drug-eluting stent. During stent expansion, these spikes deploy synchronously and penetrate the calcified plaque, penetrating deep into the vascular media and even adventitia. This allows for deep, localized drug delivery to the calcified lesion, enhancing drug distribution and therapeutic efficacy.

[0004] Although the above design has improved the ability to target and deliver drugs to calcified lesions to a certain extent, it still has certain limitations in actual clinical applications. Calcified lesions are usually characterized by irregular morphology and uneven thickness distribution. For thorn-like structures with fixed lengths, they lack adaptive adjustment capabilities and are difficult to cope with the differences in calcification thickness in different regions. Specifically, in areas with thicker calcifications, some thorn-like components cannot be fully penetrated due to the large penetration resistance; while in areas with thinner calcifications, thorn-like components of the same length may only slightly contact or even not fully contact the lesions, resulting in insufficient or uneven drug release, which in turn affects the overall treatment effect, especially when dealing with complex, multifocal calcified lesions. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a drug-eluting stent in view of the above-mentioned defects in the prior art, which is intended to better achieve drug release when treating irregularly shaped calcified lesions.

[0006] 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 to support 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 having an elastically deformable portion and being configured to adaptively deform according to the thickness of the calcified lesion it contacts, thereby achieving effective penetration of irregular calcified lesions and promoting drug release.

[0007] Furthermore, each thorn-shaped member is in a sheet-like structure as a whole, and gradually deviates from the stent body from the proximal end to the distal end when the stent body is in the expanded state.

[0008] Furthermore, each thorn-shaped member includes a fixed section, a deformable section and a spike section, wherein the fixed section is connected to the outer surface of the stent body, and the deformable section is connected between the fixed section and the spike section and forms a portion of the thorn-shaped member that can undergo elastic deformation.

[0009] Furthermore, the fixing section is located on the outer circumference of the bracket body, and the deformation section and the spike section are tilted outward relative to the fixing section.

[0010] Furthermore, the deformation section is provided with a slotted structure to form a spring structure to form a portion of the thorn-shaped member that can undergo elastic deformation.

[0011] Furthermore, the inner wall surface of the grooved structure is coated with a drug coating.

[0012] Furthermore, the slotted structure forms at least one arcuate region.

[0013] Furthermore, the slotted structures are located on both sides of the length direction of the deformation section, and the fixed section and the spike section are respectively connected to the two ends of the length direction of the deformation section.

[0014] Furthermore, the slotted structure includes at least a first group of slots and a second group of slots, the first group of slots runs through one side of the deformation section, and the second group of slots runs through the other side of the deformation section.

[0015] Furthermore, the first group of slots and the second group of slots are arranged alternately.

[0016] Compared to existing technologies, the present invention utilizes multiple thorn-like members with elastically deformable portions. When the stent switches from a contracted to an expanded state, these members adaptively deform according to the thickness of the calcified lesion they encounter, effectively penetrating irregular calcified lesions and promoting drug release. Even in calcified lesions with widely varying thicknesses, all the thorn-like members maintain excellent penetration and structural stability, ensuring uniform drug distribution within the target lesion area, significantly improving drug utilization and therapeutic efficacy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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.

[0018] Figure 1 It is a schematic diagram of the overall structure of embodiment 1 of the present invention.

[0019] Figure 2 yes Figure 1 Enlarged view of part A in the middle.

[0020] Figure 3 yes Figure 2 Schematic diagram of the structure of the middle deformation segment and the spike segment.

[0021] Figure 4 and Figure 5 It is a structural schematic diagram of the deformation segment and the spike segment in the second embodiment of the present invention.

[0022] 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.

[0023] 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

[0024] 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.

[0025] 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.

[0026] Example 1: 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.

[0027] 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.

[0028] 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.

[0029] 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 the elastically deformable portion of the thorn-shaped member 20. This allows the spike segment 23 to contact calcified lesions of varying thicknesses and then adaptively deform, thereby enabling the spike segment 23 to effectively penetrate irregular calcified lesions and promote drug release.

[0030] To 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 the 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, each formed as a U-shaped groove. 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.

[0031] 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.

[0032] It can be seen that the drug-eluting stent of this embodiment can effectively deal with calcified lesions of different thicknesses, ensure that the drug can be evenly distributed in the target lesion area, and significantly improve the drug utilization rate and treatment effect.

[0033] Example 2: Different from Example 1, Figure 4 and Figure 5 As shown, the structure of the spike section 23 of this embodiment is different. In this embodiment, 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 in a natural state, the three sections fit together to form a compact structure, such as a triangle. For details, see Figure 4 This design not only allows the spike segment 23 to maintain a compact shape when unstressed, facilitating smooth stent delivery, but also allows the three segments to elastically deform and separate relative to the root when subjected to a reverse force from a 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 insertion efficiency, thereby enhancing the effect of inhibiting vascular restenosis and improving the overall therapeutic performance of the stent.

[0034] 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 5 As shown. The tip of the second segment 232 protrudes more than the tips of the first segment 231 and the third segment 233, so that when puncturing a calcified lesion, the second segment 232 first contacts and penetrates the calcified lesion, acting as an anchor. Furthermore, the second segment 232 is larger than the first segment 231 and the third segment 233 to reinforce the anchoring effect. Due to the relatively large size of the second segment 232, a drug loading groove 40 is provided on the second segment 232. The drug loading groove 40 is not through-hole, forming a drug loading space within the drug loading groove 40 and is filled with a drug coating, further enhancing the therapeutic effect.

[0035] 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.

[0036] As can be seen, this embodiment adopts a split structure for the spike segment, consisting of at least a first segment and a second segment connected at the root. This split structure maintains a close fit in its natural state, forming a compact shape, which facilitates the smooth delivery of the stent. During the insertion process, the first and second segments can be relatively expanded under the action of external force, 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 insertion efficiency, thereby enhancing the effect of inhibiting vascular restenosis and improving the overall therapeutic performance of the stent. In addition, this split design not only improves insertion efficiency, but also better adapts to calcified lesions of different thicknesses and shapes. When dealing with thicker calcified lesions, the multi-segment structure of the spike segment can effectively disperse pressure, avoiding excessive stress concentration that may lead to insertion failure or damage to surrounding tissue. When dealing with thinner calcified lesions, the multi-segment structure can provide a larger contact area, ensuring that the drug is evenly distributed throughout the lesion area, significantly improving drug utilization and therapeutic effect.

[0037] The other structures of this embodiment are consistent with those of the first embodiment and will not be described again here.

[0038] 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 has an elastically deformable portion and is configured to adaptively deform according to the thickness of the calcified lesion it contacts, thereby effectively penetrating irregular calcified lesions and promoting drug release. Each thorn-shaped member includes a fixed segment, a deformable segment, and a spike segment. The fixed segment is connected to the outer surface of the stent body, and the deformable segment is connected between the fixed segment and the spike segment and forms the elastically deformable portion of the thorn-shaped member.

2. The drug-eluting stent according to claim 1, wherein: Each thorn-shaped member is in a sheet-like structure as a whole, and gradually deviates from the stent body from the proximal end to the distal end when the stent body is in an expanded state.

3. The drug-eluting stent according to claim 1, wherein: The fixing section is located on the outer circumference of the bracket body, and the deformation section and the spike section are tilted outward relative to the fixing section.

4. The drug-eluting stent according to claim 1, wherein: The deformation section is provided with a slotted structure to form a spring structure and form a portion of the thorn-shaped component that can undergo elastic deformation.

5. The drug-eluting stent according to claim 4, characterized in that: The inner wall surface of the grooved structure is coated with a drug coating.

6. The drug-eluting stent according to claim 4, characterized in that: The slotted structure forms at least one arcuate region.

7. The drug-eluting stent according to claim 4, characterized in that: The slotted structures are located on both sides of the length direction of the deformation section, and the fixed section and the spike section are respectively connected to the two ends of the length direction of the deformation section.

8. The drug-eluting stent according to claim 7, characterized in that: The slotted structure comprises at least a first group of slots and a second group of slots, wherein the first group of slots runs through one side of the deformation section, and the second group of slots runs through the other side of the deformation section.

9. The drug-eluting stent according to claim 8, characterized in that: The first group of slots and the second group of slots are arranged alternately.

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