Drug eluting stent

Abstract

The invention discloses a drug eluting stent, which comprises a stent main body and a plurality of thorn-shaped components, the stent main body has a radially compressible contraction state and a radially self-expanding expansion state to support blood vessels, and the plurality of thorn-shaped components are arranged on the outer surface of the stent main body and coated with a drug coating for inhibiting vascular restenosis. The spine-shaped components are arranged on the stent body and are configured to protrude towards the outer side of the stent body from the outer surface of the stent body to penetrate into calcified lesions on the inner wall of a blood vessel when the stent body is switched from the contraction state to the expansion state, each spine-shaped component is provided with a part capable of generating elastic deformation, and the spine-shaped components are configured to be capable of generating deformation in a self-adaptive mode according to the thickness of the contacted calcified lesions. Therefore, the medicine can be uniformly distributed in a target lesion area, and the utilization rate of the medicine and the treatment effect are remarkably improved.

Description

Technical Field

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

[0002] In the interventional treatment of vascular stenosis, drug-eluting stents have gradually replaced metal bare stents with relatively simple structures and become the mainstream treatment method in clinical applications because they can effectively inhibit restenosis after surgery. Such stents are coated with a drug coating that inhibits vascular restenosis on their surface, and 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, when dealing with stenotic lesions accompanied by calcified lesions, traditional drug-eluting stents still face certain challenges. Due to the hard texture and poor permeability of calcified lesions, they may hinder the effective diffusion of drugs from the stent coating to the deep blood vessel wall, affecting the treatment effect.

[0003] To solve the above problems, Chinese Patent CN113599032A adds multiple micro-spikes with the same length on the basis of traditional drug-eluting stents. When the stent expands, these spikes are deployed synchronously and penetrate into the calcified plaque, reaching the middle or even outer membrane layer of the blood vessel, realizing local deep drug delivery to the calcified lesion area, thereby enhancing the distribution efficiency and therapeutic effect of the drug at the lesion site.

[0004] Although the above design improves the targeted drug delivery ability to calcified lesions to a certain extent, there are still certain limitations in actual clinical applications. Calcified lesions usually have characteristics such as irregular shapes and uneven thickness distributions. For a spiky structure with a fixed length, it lacks the ability of adaptive adjustment and is difficult to cope with the differences in calcification thickness in different regions. Specifically, in areas with thicker calcification, some spiky components cannot fully penetrate due to greater penetration resistance; while in areas with thinner calcification, spiky components of the same length may only slightly contact or even not fully contact the lesion, resulting in insufficient drug release or uneven distribution, thereby affecting the overall treatment effect, especially when dealing with complex and 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 aiming at the above-mentioned defects in the prior art, which can better achieve drug release when dealing with 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 contracted state in which it is radially compressible and an expanded state in which it is radially self-expandable to support a blood vessel, wherein the plurality of thorn-like 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 to penetrate into calcified lesions on the inner wall of the blood vessel when the stent body is switched from the contracted state to the expanded state, wherein each thorn-like member has a portion that can undergo elastic deformation, and is configured to be able 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.

[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 an 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, a slotted structure is provided on the deformation section 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] Further, the slotted structure forms at least one arcuate area.

[0013] Furthermore, the slotted structure is 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 comprises 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 with the prior art, by providing a plurality of spiky members with elastic deformation portions, when the stent switches from the contracted state to the expanded state, the present invention can adaptively deform according to the thickness of the contacted calcified lesion, thereby effectively penetrating the irregular calcified lesion and promoting drug release. Even in the calcified lesion area with a large thickness difference, all the spiky members can still maintain good penetration and structural stability, ensuring that the drug can be evenly distributed in the target lesion area, significantly improving the drug utilization rate and treatment effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] With reference to the accompanying drawings and by referring to the following detailed description, a more complete understanding of the present invention and its accompanying advantages and features will be more easily obtained.

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

[0019] Figure 2 is Figure 1 an enlarged view of part A in

[0020] Figure 3 is Figure 2 a schematic diagram of the structure of the deformation section and the spike section in

[0021] Figure 4 and Figure 5 is a schematic diagram of the structure of the deformation section and the spike section in Embodiment 2 of the present invention.

[0022] In the drawings: 10 is the stent body; 20 is the spiky member, 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, 233 is the third section; 30 is the slotted structure, 31 is the first group of slots, 32 is the second group of slots; 40 is the drug-carrying groove.

[0023] It should be noted that the drawings are used to illustrate the present invention, rather than to limit the present invention. Note that the drawings showing the structure may not be drawn to scale. And in the drawings, the same or similar elements are labeled with the same or similar reference numerals. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] In order to make the content of the present invention clearer and easier to understand, the content of the present invention will be described in detail below with reference to specific embodiments and the accompanying drawings.

[0025] As used herein, "proximal" and "distal" with respect to the present invention should be understood as, when observed from the direction of the attending physician, "proximal" refers to the end closer to the attending physician, i.e., corresponding to the "left end" as indicated in the reference drawings, and "distal" refers to the end farther from the attending physician, i.e., corresponding to the "right end" as indicated in the reference drawings.

[0026] Embodiment 1: AsFigures 1 to 3 As shown, the drug-eluting stent of this embodiment includes a stent body 10 and a plurality of spiky members 20. The stent body 10 is a hollow tubular structure, which is formed by laser engraving a metal tube, such as a nitinol tube, and then heat-treated to be shaped. A number of meshes are formed on the surface, and it has a radially contracted state and a radially self-expanding state to support the blood vessel. This not only ensures the flexibility and strength of the stent, but also ensures that it can be smoothly deployed in the body and stably support the blood vessel wall. The selection of nitinol alloy material enables the stent to have good biocompatibility and shape memory function, and can maintain its structural stability in different environments. It should be noted that in the actual use process, this embodiment often needs to rely on the inflation of a balloon to push the stent body 10 to expand, so that the plurality of spiky members 20 can penetrate into the lesion.

[0027] The plurality of spiky members 20 are circumferentially arranged on the outer surface of the stent body 10. These spiky members 20 and the stent body 10 are integrally formed by heat setting after laser engraving, ensuring the consistency and stability of the structure. After being integrally formed, 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 elaborated here. The design of this drug coating helps to improve the drug utilization rate 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 the contracted state to the expanded state, the plurality of spiky members 20 protrude from the outer surface of the stent body 10 towards the outside of the stent body 10 to penetrate the calcified lesion on the inner wall of the blood vessel, so as to achieve deep drug delivery to the calcified lesion area. The spiky member 20 as a whole is in a sheet structure, and gradually deviates from the stent body 10 in the direction from the proximal end to the distal end when the stent body 10 is in the expanded state, which is convenient for safely withdrawing the entire drug-eluting stent from the distal end towards the proximal end from the human body. Each spiky member 20 has an elastically deformable part, and is configured to be able to adaptively deform according to the thickness of the contacted calcified lesion, so as to effectively penetrate the irregular calcified lesion and promote drug release. Even in the calcified lesion area with a large thickness difference, all the spiky members 20 can still maintain good penetration and structural stability, ensuring that the drug can be evenly distributed in the target lesion area, significantly improving the drug utilization rate and treatment effect.

[0029] Each thorn-shaped member 20 includes a fixed section 21, a deformable section 22 and a spike section 23 connected in sequence, and the spike section 23 is the portion of the thorn-shaped member 20 away from the outer surface of the stent body 10. The fixed section 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 section 22 and the spike section 23 are tilted outward relative to the fixed section 21, so that when the stent body 10 is in an expanded state, the deformable section 22 and the spike section 23 can gradually deviate from the stent body 10 from the proximal end to the distal end. The deformable section 22 is connected between the fixed section 21 and the spike section 23, forming a portion of the thorn-shaped member 20 that can be elastically deformed, allowing the spike section 23 to contact calcified lesions of different thicknesses, and then the deformable section 22 can be deformed adaptively, so as to achieve effective penetration of the spike section 23 into irregular calcified lesions and promote drug release.

[0030] In order to enhance the elastic deformation ability of the thorn-shaped member 20, a slotted structure 30 is provided on the deformation section 22 to form a spring-like structure. These slotted structures 30 are located on both sides of the length direction of the deformation section 22, and the fixed section 21 and the spike section 23 are respectively connected to the two ends of the length direction of the deformation section 22. The slotted structure 30 includes at least a first group of slots 31 and a second group of slots 32, and the first group of slots 31 and the second group of slots 32 are both formed as U-shaped slots, the first group of slots 31 runs through one side of the deformation section 22, and the second group of slots 32 runs through the other side of the deformation section 22, and the first group of slots 31 and the second group of slots 32 are staggered, so that the slotted structure 30 forms at least one arched area, thereby simulating the effect of a spring. This design not only improves the elastic response ability of the thorn-shaped member 20, but also enhances its adaptability in lesions of different 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, and when encountering a thinner lesion, it will bend slightly or not bend, thereby ensuring that each thorn-like member 20 can effectively penetrate the diseased tissue, and each thorn-like member 20 is relatively independent and does not affect each other.

[0031] Moreover, the inner wall surface of the slotted structure 30 is also coated with a drug coating, that is, the first group of slots 31 and the second group of slots 32 not only act as springs, but also contain drug coatings inside, which not only increases the drug loading of the entire thorn-shaped member 20, but also ensures that the drug can be quickly released when it contacts the diseased tissue to achieve the best therapeutic effect. This multi-layer drug coating design allows the drug to be more evenly distributed throughout the diseased area, significantly improving the drug utilization rate and therapeutic effect. In addition, due to the presence of the slotted structure 30, the drug can be released at different positions of the thorn-shaped member 20, further increasing the penetration depth and coverage of the drug.

[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] Embodiment 2: Different from Embodiment 1, as shown in combination with Figure 4 and Figure 5 shown, the structure of the spike segment 23 in this embodiment is different. In this embodiment, the spike segment 23 is a split structure and includes a first segment 231, a second segment 232, and a third segment 233 whose roots are connected together. The roots of the first segment 231, the second segment 232, and the third segment 233 are connected to different positions of the end of the deformation segment 22 away from the stent body 10, and are configured to fit together to form a compact structure such as a triangle in the natural state. For specific reference, see Figure 4 shown. This design not only keeps the spike segment 23 in a compact shape when not stressed, which is beneficial to the smooth delivery of the stent, but also when receiving a reverse force from the calcified lesion, the three can elastically deform and separate relative to the root, thereby increasing the piercing angle and contact area, significantly improving the coverage range and piercing depth of the calcified lesion area, reducing the risk of slippage, improving the piercing efficiency, thereby enhancing the effect of inhibiting vascular restenosis and improving the overall treatment performance of the stent.

[0034] Specifically, the first segment 231, the second segment 232, and the third segment 233 are integrally formed on the outer surface of the stent body 10 by a laser cutting process. The first segment 231 and the third segment 233 are symmetrically arranged on both sides of the second segment 232, and can deviate from the second segment 232 in opposite directions respectively when receiving a reverse force from the calcified lesion. For specific reference, see Figure 5 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 piercing the calcified lesion, the second segment 232 first contacts and pierces the calcified lesion to play an anchoring role. In addition, the size of the second segment 232 is larger than the sizes of the first segment 231 and the third segment 233 to strengthen the anchoring effect. Since the size of the second segment 232 is relatively large, a drug-carrying groove 40 is provided on the second segment 232. The drug-carrying groove 40 does not penetrate, and a drug-carrying space is formed inside the drug-carrying groove 40 and filled with a drug coating, further improving the treatment effect.

[0035] To better understand the design flexibility of the spike segment 23, it can be understood that the spike segment 23 can also only include a first segment and a second segment connected at the root, or include more segments according to actual needs. As long as it is satisfied that the spike segment includes at least a first segment and a second segment connected at the root and is a split structure, and a predetermined gap is left between the first segment and the second segment to allow the two to separate along the root after being subjected to the reverse force of the autocalcified lesion to achieve a larger angle of piercing into the calcified lesion. This flexible design can be adjusted according to different clinical needs to achieve the best treatment effect.

[0036] Thus, in this embodiment, the spike segment adopts a split structure composed of at least a first segment and a second segment connected at the root. This split structure remains adhered in the natural state, forming a compact shape, which is beneficial to the smooth delivery of the stent. During the piercing process, the first segment and the second segment can be relatively unfolded under the action of an external force, thereby increasing the piercing angle and the contact area, significantly improving the coverage range and piercing depth of the calcified lesion area, reducing the risk of slippage, improving the piercing efficiency, thus enhancing the effect of inhibiting vascular restenosis and improving the overall treatment performance of the stent. In addition, this split design not only improves the piercing efficiency but also better adapts to calcified lesions of different thicknesses and shapes. When facing a thicker calcified lesion, the multi-segment structure of the spike segment can effectively disperse the pressure, avoiding the piercing failure or damage to the surrounding tissues caused by excessive stress concentration; when facing a thinner calcified lesion, the multi-segment structure can provide a larger contact area to ensure that the drug can be evenly distributed throughout the lesion area, significantly improving the drug utilization rate and treatment effect.

[0037] Other structures of this embodiment are the same as those of the first embodiment and will not be elaborated here.

[0038] It can be understood that although the present invention has been disclosed above with 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, many possible changes and modifications can be made to the technical solution of the present invention by using the technical content disclosed above, or modified into equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to 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 the protection of the technical solution of the present invention.

Claims

1. A drug-eluting stent, comprising a stent body and a plurality of spiky 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 spiky members are disposed on the outer surface of the stent body and are coated with a drug coating for inhibiting restenosis of the blood vessel, and are configured to protrude outward from the outer surface of the stent body toward the outside of the stent body to pierce into a calcified lesion of the inner wall of the blood vessel when the stent body switches from the contracted state to the expanded state, wherein, Each thorn-shaped member has an elastically deformable portion and is configured to be adaptively deformed according to the thickness of the contacted calcified lesion, so as to achieve effective penetration into the irregular calcified lesion and promote drug release.

2. The drug-eluting stent according to claim 1, characterized in that, 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, characterized in that, Each thorn-shaped member includes a fixed section, a deformable section and a spike section. The fixed section is connected to the outer surface of the bracket body, and the deformable section is connected between the fixed section and the spike section and forms a part of the thorn-shaped member that can undergo elastic deformation.

4. The drug-eluting stent according to claim 3, 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.

5. The drug-eluting stent according to claim 3, characterized in that, The deformation section is provided with a slotted structure to form a spring structure to form a portion of the thorn-shaped component that can undergo elastic deformation.

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

7. The drug-eluting stent according to claim 5, characterized in that, The slotted structure forms at least one arcuate region.

8. The drug-eluting stent according to claim 5, wherein, 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.

9. The drug-eluting stent according to claim 8, characterized in that, The slotted structure at least includes 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.

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

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