Stent structure, medical stent, and preparation method therefor

Abstract

The present application relates to a stent structure, a medical stent, and a preparation method therefor. A first end stent segment (1000) and a second end stent segment (2000) have a first stent body flexibility. A first spacer stent segment (3000) and a second spacer stent segment (4000) have a second stent body flexibility. A middle stent segment (5000) has a third stent body flexibility. The first stent body flexibility is less than the second stent body flexibility, and the second stent body flexibility is less than the third stent body flexibility.

Description

Scaffold structure, medical stent and its preparation method

[0001] Related applications

[0002] This application claims priority to Chinese patent application filed on May 30, 2024, application number 2024106949220, entitled "Stent Structure, Medical Stent and Method of Preparation Thereof", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of medical device technology, and in particular to stent structures, medical stents and their preparation methods. Background Technology

[0004] Cardiovascular diseases seriously affect people's health. Vascular prostheses such as stents are widely used in the treatment of various vascular access abnormalities, such as aneurysms, dissections, embolisms, and stenosis. Laser-cut stents, due to their flexible design capabilities, have been widely used in the endovascular treatment of various vascular diseases. In clinical applications, the use of stents has significantly improved vascular patency and effectively improved patient outcomes. However, problems still exist, including irritation of healthy blood vessels, poor flexibility, poor stent deployment morphology, poor fatigue fracture resistance, and in-stent restenosis.

[0005] To address these issues, drug-eluting stents have been developed. Drug-eluting stents involve coating the stent surface with a specific coating using a specific method. When the stent is placed at the lesion site, the drug is controllably eluted from the stent, thereby inhibiting intimal hyperplasia and further improving late-stage patency. Drugs used include rapamycin and paclitaxel, both of which can inhibit the proliferation and migration of smooth muscle cells. However, due to the combined effects of bending, twisting, compression, and squeezing on the arteries of the lower limbs, the stent is subjected to severe stress, making it prone to fracture, restenosis, and reduced patency. Since the stent tip is anchored to a healthy blood vessel, the stimulation of the healthy vessel by the stent tip also affects long-term patency. Furthermore, poor stent deployment morphology can keep the stent under constant stress, reducing its fatigue resistance, increasing the fracture rate, and further decreasing long-term patency. Summary of the Invention

[0006] According to various embodiments of this application, this application provides a stent structure, a medical stent, and a method for preparing the same.

[0007] This application provides a support structure, the support structure comprising:

[0008] Mid-section support;

[0009] The first spacer support segment and the second spacer support segment are respectively connected to both ends of the middle support segment.

[0010] A first end support segment and a second end support segment, wherein the first end support segment is connected to the end of the first spacer support segment, and the second end support segment is connected to the end of the second spacer support segment;

[0011] At least one of the first end support segment and the second end support segment has a first frame flexibility, at least one of the first spacer support segment and the second spacer support segment has a second frame flexibility, and the middle support segment has a third frame flexibility. The first frame flexibility is less than the second frame flexibility, and the second frame flexibility is less than the third frame flexibility.

[0012] In one embodiment, the first end support segment includes a plurality of first support unit rings, each of which has a plurality of first peaks and first troughs arranged sequentially in the circumferential direction. The plurality of first support unit rings are arranged along the axial direction of the first end support segment, and the first peaks and first troughs of adjacent first support unit rings that are closest in axial distance are connected.

[0013] In one embodiment, adjacent first peaks and first troughs are connected by a first connecting element.

[0014] In one embodiment, the straight line connecting the first crest and the first trough is parallel to the axis of the first end support segment.

[0015] In one embodiment, the straight line connecting the first crest and the first trough is at an angle to the axis of the first end support segment.

[0016] In one embodiment, the straight line connecting the connected first peak and the first trough forms an angle with the axis of the first end support segment, such that the connected first peak and the first trough have a first offset distance in the circumferential direction of the first end support segment, the first offset distance being less than the straight-line distance between the connected first peak and the first trough.

[0017] In one embodiment, the first connecting element is at least one of a straight rod, an S-shaped rod, a V-shaped rod, an N-shaped rod, or an Ω-shaped rod;

[0018] In one embodiment, the second end support segment includes a plurality of second support unit rings, each second support unit ring having a plurality of second peaks and second troughs arranged sequentially at intervals in the circumferential direction. The plurality of second support unit rings are arranged along the axial direction of the second end support segment, and the second peak and second trough that are closest in axial distance among adjacent second support unit rings are connected.

[0019] In one embodiment, adjacent second peaks and second troughs are connected by a second connecting element.

[0020] In one embodiment, the straight line connecting the second crest and the second trough is parallel to the axis of the second end support segment.

[0021] In one embodiment, the straight line connecting the second crest and the second trough forms an angle with the axis of the second end support segment.

[0022] In one embodiment, the straight line connecting the connected second peak and the second trough forms an angle with the axis of the second end support segment, such that the connected second peak and the second trough have a second offset distance in the circumferential direction of the second end support segment, the second offset distance being less than the straight-line distance between the connected second peak and the second trough.

[0023] In one embodiment, the second connecting element is at least one of a straight rod, an S-shaped rod, a V-shaped rod, an N-shaped rod, or an Ω-shaped rod.

[0024] In one embodiment, the first spacer segment includes a plurality of third support unit rings, each third support unit ring having a plurality of third peaks and third troughs arranged sequentially in the circumferential direction. The plurality of third support unit rings are arranged along the axial direction of the first spacer segment, and the third peaks and third troughs of adjacent third support unit rings that are closest in axial distance are connected.

[0025] In one embodiment, adjacent third peaks and third troughs are connected by a third connecting element.

[0026] In one embodiment, the straight line connecting the connected third peak and the third trough is parallel to the axis of the first spacer segment.

[0027] In one embodiment, the straight line connecting the connected third peak and the third trough forms an angle with the axis of the first spacer segment.

[0028] In one embodiment, the straight line connecting the connected third peak and the third trough forms an angle with the axis of the first spacer segment, such that the connected third peak and the third trough have a third offset distance in the circumferential direction of the first spacer segment, the third offset distance being less than the straight-line distance between the connected third peak and the third trough.

[0029] In one embodiment, the third connecting element is at least one of a straight rod, an S-shaped rod, a V-shaped rod, an N-shaped rod, or an Ω-shaped rod.

[0030] In one embodiment, the second spacer segment includes a plurality of fourth support unit rings, each fourth support unit ring having a plurality of fourth peaks and fourth troughs arranged sequentially in the circumferential direction. The plurality of fourth support unit rings are arranged along the axial direction of the second spacer segment, and the fourth peaks and fourth troughs of adjacent fourth support unit rings that are closest in axial distance are connected.

[0031] In one embodiment, adjacent fourth peaks and fourth troughs are connected by a fourth connecting element.

[0032] In one embodiment, the straight line connecting the connected fourth peak and the fourth trough is parallel to the axis of the second spacer segment.

[0033] In one embodiment, the straight line connecting the fourth peak and the fourth trough forms an angle with the axis of the second spacer segment.

[0034] In one embodiment, the straight line connecting the connected fourth peak and the fourth trough forms an angle with the axis of the second spacer segment, such that the connected fourth peak and the fourth trough have a fourth offset distance in the circumferential direction of the second spacer segment, the fourth offset distance being less than the straight-line distance between the connected fourth peak and the fourth trough.

[0035] In one embodiment, the fourth connecting element is at least one of a straight rod, an S-shaped rod, a V-shaped rod, an N-shaped rod, or an Ω-shaped rod.

[0036] In one embodiment, the central support segment includes a plurality of fifth support unit rings, each fifth support unit ring having a plurality of fifth peaks and fifth troughs arranged sequentially in the circumferential direction. The plurality of fifth support unit rings are arranged along the axial direction of the central support segment, and the fifth peaks of adjacent fifth support unit rings that are closest in axial distance are connected to each other.

[0037] In one embodiment, portions of the fifth peaks in adjacent fifth support unit rings are connected by a fifth connecting element.

[0038] In one embodiment, the straight line connecting the connected fifth peaks is parallel to the axis of the middle support segment.

[0039] In one embodiment, the straight line connecting the connected fifth peaks forms an angle with the axis of the middle support segment.

[0040] In one embodiment, the fifth connecting element is at least one of a straight rod, an S-shaped rod, a V-shaped rod, an N-shaped rod, or an Ω-shaped rod.

[0041] In one embodiment, adjacent third support unit rings have multiple pairs of third peaks and third valleys that cooperate axially in the first spaced support segment along the circumferential direction, and the multiple pairs of third peaks and third valleys that are connected or not connected are arranged sequentially at intervals in the circumferential direction of the third support unit rings.

[0042] In one embodiment, adjacent fourth support unit rings have multiple pairs of fourth peaks and fourth valleys that cooperate axially in the second spaced support segment along the circumferential direction, and the multiple pairs of fourth peaks and fourth valleys that are connected or not connected are arranged sequentially at intervals in the circumferential direction of the fourth support unit rings.

[0043] In one embodiment, adjacent fifth support unit rings have multiple pairs of fifth peaks that cooperate axially in the middle support section along the circumferential direction. The number of non-connected fifth peak pairs is an integer multiple of the number of connected fifth peak pairs. The connected fifth peaks in different adjacent fifth support units are staggered in the circumferential direction of the middle support section.

[0044] In one embodiment, the first end support segment includes a plurality of first support unit rings, each of which has a plurality of first peaks and first troughs arranged sequentially in the circumferential direction. The plurality of first support unit rings are arranged along the axial direction of the first end support segment, and the first peaks and first troughs that are closest in axial distance among adjacent first support unit rings are connected.

[0045] The second end support segment includes a plurality of second support unit rings. The second support unit rings have a plurality of second peaks and second troughs arranged sequentially in the circumferential direction. The plurality of second support unit rings are arranged along the axial direction of the second end support segment. The second peak and the second trough that are closest in axial distance among adjacent second support unit rings are connected.

[0046] The first spacer segment includes a plurality of third support unit rings. Each third support unit ring has a plurality of third peaks and third valleys arranged sequentially in the circumferential direction. The plurality of third support unit rings are arranged along the axial direction of the first spacer segment. The third peaks and third valleys of adjacent third support unit rings that are closest in axial distance are connected.

[0047] The second spacer segment includes a plurality of fourth support unit rings. Each fourth support unit ring has a plurality of fourth peaks and fourth valleys arranged sequentially in the circumferential direction. The plurality of fourth support unit rings are arranged along the axial direction of the second spacer segment. The fourth peaks and fourth valleys of adjacent fourth support unit rings that are closest in axial distance are connected.

[0048] The central support section includes multiple fifth support unit rings. Each fifth support unit ring has multiple fifth peaks and fifth troughs arranged sequentially in the circumferential direction. The multiple fifth support unit rings are arranged along the axial direction of the central support section, and the fifth peaks of adjacent fifth support unit rings with the closest axial distance are connected.

[0049] In one embodiment, a portion of the first trough of the first support unit ring located at the end of the first end support segment is connected to a portion of the third peak of the third support unit ring located at the end of the first spaced support segment.

[0050] In one embodiment, a portion of the second peak of the second support unit ring located at the end of the second end support segment is connected to a portion of the fourth valley of the fourth support unit ring located at the end of the second spaced support segment.

[0051] In one embodiment, a portion of the third trough of the third support unit ring located at the end of the first spaced support segment is connected to a portion of the fifth peak of the fifth support unit ring located at the end of the middle support segment, wherein the portion of the fifth peak does not simultaneously connect the portion of the third trough and the fifth peak of other fifth support unit rings in the middle support segment.

[0052] In one embodiment, a portion of the fourth peak of the fourth support unit ring located at the end of the second spacer segment is connected to a portion of the fifth valley of the fifth support unit ring located at the end of the middle support segment, wherein the portion of the fifth valley does not simultaneously connect the portion of the fourth peak and the fifth valley of other fifth support unit rings in the middle support segment.

[0053] In one embodiment, the central support segment includes a plurality of fifth support unit rings, each fifth support unit ring having a plurality of fifth peaks and fifth troughs arranged sequentially in the circumferential direction, wherein the peak width of the fifth peak is greater than the support width of the fifth support unit ring.

[0054] In one embodiment, the crest width of the fifth peak is 1.1 to 3 times the support width of the fifth support unit ring.

[0055] This application provides a medical stent, the medical stent including the stent structure, at least a portion of the surface of the stent structure being provided with a polymer layer, and at least a portion of the surface of the polymer layer being provided with a drug coating.

[0056] This application provides a method for preparing the medical stent, the method comprising the following steps:

[0057] A first polymer is dissolved in a first organic solvent to obtain a first solution, and the first solution is disposed on the surface of the support structure to form the polymer layer;

[0058] A second solution is obtained by dissolving the second polymer and the active pharmaceutical ingredient in a second organic solvent, and the second solution is disposed on the surface of the polymer layer to form the drug coating.

[0059] Details of one or more embodiments of this application are set forth in the following drawings and description, and other features, objects and advantages of this application will become apparent from the specification, drawings and claims. Attached Figure Description

[0060] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the disclosed drawings without creative effort.

[0061] Figure 1 is a schematic diagram of the support structure provided in some embodiments of this application.

[0062] Figure 2 is a partial schematic diagram of the support structure provided in some embodiments of this application.

[0063] Figure 3 is a schematic diagram comparing the crest width and the support width of the support structure in the prior art.

[0064] Figure 4 is a schematic diagram comparing the crest width and the support width of the support structure in some embodiments of this application.

[0065] Figure 5 is a cross-sectional schematic diagram of the support structure provided in some embodiments of this application.

[0066] Figure 6 is a three-dimensional schematic diagram of the support structure provided in some embodiments of this application.

[0067] Reference numerals: 100, scaffold structure; 200, polymer layer; 300, drug coating; 1000, first end scaffold segment; 2000, second end scaffold segment; 3000, first spacer scaffold segment; 4000, second spacer scaffold segment; 5000, middle scaffold segment; 6000, imaging element; 1100, first scaffold unit ring; 1100a, first peak; 1100b, first trough; 1200, first connecting element; 2100, second scaffold unit ring; 2100a, second peak; 2100b, second trough; 2200, second connecting element; 3100, third scaffold unit ring; 3100a, third peak; 3100b, third trough; 3200, third connecting element; 4100, fourth scaffold unit ring; 4100a, fourth peak; 4100b, fourth trough; 4200, fourth connecting element; 5100, Fifth support unit ring; 5100a, Fifth crest; 5100b, Fifth trough; 5200, Fifth connecting element; 5000a, Crest width; 5000b, Support width; 5000c, Stress concentration location. Detailed Implementation

[0068] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0069] In the support structure 100, each peak represents the upward-facing pointed portion as shown in Figure 1, and each trough represents the downward-facing pointed portion as shown in Figure 1.

[0070] As shown in Figures 1 and 2, one embodiment of this application provides a support structure 100, which includes five sections: a first end support section 1000, a second end support section 2000, a first spacer support section 3000, a second spacer support section 4000, and a middle support section 5000. Referring to Figure 1, the first spacer support section 3000 and the second spacer support section 4000 are respectively connected to both ends of the middle support section 5000, the first end support section 1000 is connected to the end of the first spacer support section 3000, and the second end support section 2000 is connected to the end of the second spacer support section 4000.

[0071] The support structure 100 provided in this application defines at least one of the first end support segment 1000 and the second end support segment 2000 as having a first frame flexibility, at least one of the first spacer support segment 3000 and the second spacer support segment 4000 as having a second frame flexibility, and the middle support segment 5000 as having a third frame flexibility. The first frame flexibility is less than the second frame flexibility, and the second frame flexibility is less than the third frame flexibility.

[0072] For example, the first end support segment 1000 and the second end support segment 2000 have the same flexibility, making both the first end support segment 1000 and the second end support segment 2000 the first frame flexibility. Similarly, the first spacer support segment 3000 and the second spacer support segment 4000 have the same flexibility, making both the first spacer support segment 3000 and the second spacer support segment 4000 the second frame flexibility. Therefore, the first end support segment 1000 and the second end support segment 2000, located at both ends of the support structure 100, will be the two segments with the lowest flexibility in the entire support structure 100, that is, the two segments with the highest stiffness. The central support segment 5000, located in the center of the support structure 100, will be the segment with the highest flexibility in the entire support structure 100. The first interval support section 3000 and the second interval support section 4000, which are located between the middle support section 5000 and the first end support section 1000 and the second end support section 2000, will be the two sections with moderate flexibility in the entire support structure 100. The flexibility of these two sections has a transitional function.

[0073] The compliant design of the first and second end stent segments 1000 and 2000 ensures sufficient support for secure anchoring. The compliant design of the first and second septal stent segments 3000 and 4000 ensures a certain degree of stent flexibility while improving the transmission of axial force during stent deployment, enhancing positioning accuracy, reducing poor stent deployment morphology caused by inaccurate positioning or shortening of the stent structure 100, ensuring complete lesion coverage, and improving fatigue resistance and long-term patency. The compliant design of the middle stent segment 5000 ensures excellent flexibility, adapting to various combined forces such as peripheral vascular bending, torsion, compression, and squeezing, reducing the risk of vascular damage and stent breakage due to poor compliance of the stent structure 100.

[0074] Furthermore, the closed-loop design of the first end stent segment 1000 and the second end stent segment 2000 makes the stent structure more rounded, avoiding poor adhesion between the first end stent segment 1000 and the second end stent segment 2000 and the vessel wall, which could generate eddies during blood flow and cause restenosis. At the same time, the closed-loop design of the stent structure can also prevent the apex of the stent structure from tilting up, thus avoiding stimulation of the healthy anchoring area of ​​the vessel and reducing in-stent restenosis caused by cell proliferation.

[0075] Those skilled in the art can adjust the compliance values ​​of the first end support section 1000, the second end support section 2000, the first interval support section 3000, the second interval support section 4000, and the middle support section 5000, as well as the relative compliance differences, according to actual needs. Furthermore, those skilled in the art can adjust the compliance of the first end support section 1000, the second end support section 2000, the first interval support section 3000, the second interval support section 4000, and the middle support section 5000 through material design or structural design, etc., which is not limited here.

[0076] For example, when adjusting compliance based on structural design, in one embodiment, the first end support segment 1000 may include multiple first support unit rings 1100. Each first support unit ring 1100 has multiple first peaks 1100a and first troughs 1100b spaced apart in the circumferential direction, as shown in Figure 1. The first peak 1100a is the pointed portion of the first support unit ring 1100 facing upwards in Figure 1, and the first trough 1100b is the pointed portion of the first support unit ring 1100 facing downwards in Figure 1. The multiple first support unit rings 1100 are arranged along the axial direction of the first end support segment 1000, and the first peaks 1100a and first troughs 1100b of adjacent first support unit rings 1100 are connected. For example, adjacent first peaks 1100a and first troughs 1100b are connected by a first connecting element 1200. The first connecting element 1200 may be at least one of a straight rod, an S-shaped rod, a V-shaped rod, an N-shaped rod, or an Ω-shaped rod.

[0077] Furthermore, the straight line connecting the first peak 1100a and the first trough 1100b can be parallel to the axis of the first end support segment 1000, or the straight line connecting the first peak 1100a and the first trough 1100b can form an angle with the axis of the first end support segment 1000. When the straight line connecting the first peak 1100a and the first trough 1100b forms an angle with the axis of the first end support segment 1000, the connected first peak 1100a and the first trough 1100b can have a first offset distance in the circumferential direction of the first end support segment 1000. The setting of this first offset distance can increase the flexibility of the support structure to a certain extent, for example, especially when the support structure bends. In this case, the first offset distance can be limited to be less than the straight-line distance between the connected first peak 1100a and the first trough 1100b.

[0078] Since all the first peaks 1100a and first troughs 1100b are connected, the first end stent segment 1000 can form a fully closed-loop structure. That is, in the circumferential direction of the first end stent segment 1000, the number of first connecting elements 1200 is equal to the number of first peaks 1100a or first troughs 1100b. The number of first peaks 1100a or first troughs 1100b can be 4 to 40, and the number of first stent unit rings 1100 can be 2, 3, or other varying numbers. The fully closed-loop structure makes the structure of the first end stent segment 1000 more rounded, avoiding poor adhesion between the first end stent segment 1000 and the vessel wall, and preventing eddies and restenosis during blood flow. Simultaneously, the fully closed-loop structure also prevents the first peaks 1100a or first troughs 1100b from tilting upwards, avoiding stimulation of the healthy anchoring zone vessel and reducing in-stent restenosis caused by cell proliferation. In addition, the number of first support unit rings 1100 can also be one, in which case the first peak 1100a and the first trough 1100b at the ends may not be connected.

[0079] Similar to the first end support segment 1000, the second end support segment 2000 may include multiple second support unit rings 2100. Each second support unit ring 2100 has multiple second peaks 2100a and second troughs 2100b arranged sequentially and at intervals in the circumferential direction, as shown in Figure 1. The second peaks 2100a are the upward-facing tips of the second support unit rings 2100 in Figure 1, and the second troughs 2100b are the downward-facing tips of the second support unit rings 2100 in Figure 1. The multiple second support unit rings 2100 are arranged along the axial direction of the second end support segment 2000, and the second peaks 2100a and second troughs 2100b of adjacent second support unit rings 2100 are connected. For example, adjacent second peaks 2100a and second troughs 2100b are connected by a second connecting element 2200. The second connecting element 2200 may be at least one of a straight rod, an S-shaped rod, a V-shaped rod, an N-shaped rod, or an Ω-shaped rod.

[0080] Furthermore, the straight line connecting the connected second peak 2100a and second trough 2100b can be parallel to the axis of the second end support segment 2000, or the straight line connecting the connected second peak 2100a and second trough 2100b can form an angle with the axis of the second end support segment 2000. When the straight line connecting the connected second peak 2100a and second trough 2100b forms an angle with the axis of the second end support segment 2000, the connected second peak 2100a and second trough 2100b can have a second offset distance in the circumferential direction of the second end support segment 2000. In this case, the second offset distance can be limited to be less than the straight-line distance between the connected second peak 2100a and second trough 2100b.

[0081] Since all the second peaks 2100a and second troughs 2100b are connected, the second end stent segment 2000 can form a fully closed-loop structure. That is, in the circumferential direction of the second end stent segment 2000, the number of second connecting elements 2200 is equal to the number of second peaks 2100a or second troughs 2100b. The number of second peaks 2100a or second troughs 2100b can be 4 to 40, and the number of second stent unit rings 2100 can be 1 to 3. The fully closed-loop structure makes the structure of the second end stent segment 2000 more rounded, avoiding poor adhesion between the second end stent segment 2000 and the vessel wall, and preventing eddies and restenosis during blood flow. At the same time, the fully closed-loop structure also prevents the second peaks 2100a or second troughs 2100b from tilting upwards, avoiding stimulation of the healthy anchoring zone vessel and reducing in-stent restenosis caused by cell proliferation.

[0082] The first spacer segment 3000 may include multiple third support unit rings 3100. Each third support unit ring 3100 has multiple sequentially spaced third peaks 3100a and third troughs 3100b in the circumferential direction, as shown in Figure 1. The third peak 3100a is the pointed portion of the third support unit ring 3100 facing upwards in Figure 1, and the third trough 3100b is the pointed portion of the third support unit ring 3100 facing downwards in Figure 1. The multiple third support unit rings 3100 are arranged along the axial direction of the first spacer segment 3000, and some of the third peaks 3100a and third troughs 3100b in adjacent third support unit rings 3100 are connected. Adjacent third peaks 3100a and third troughs 3100b can be connected by a third connecting element 3200, which may be at least one of a straight rod, an S-shaped rod, a V-shaped rod, an N-shaped rod, or an Ω-shaped rod.

[0083] In one embodiment, adjacent third support unit rings 3100 have multiple pairs of third peaks 3100a and third troughs 3100b that cooperate axially with each other in the first spacer support segment 3000 along the circumferential direction. Among these multiple pairs of axially cooperating third peaks 3100a and third troughs 3100b, the connected and unconnected pairs of third peaks 3100a and third troughs 3100b are sequentially spaced apart along the circumference of the third support unit ring 3100. That is, connected third peaks 3100a and third troughs 3100b and unconnected third peaks 3100a and third troughs 3100b are arranged sequentially along the circumferential direction. In this case, the number of connected and unconnected pairs of third peaks 3100a and third troughs 3100b is the same. Alternatively, those skilled in the art can adjust the relative number of connected and unconnected pairs of third peaks 3100a and third troughs 3100b according to actual needs, which is not limited here.

[0084] Furthermore, the straight line connecting the connected third peak 3100a and third trough 3100b can be parallel to the axis of the first spacer segment 3000, or the straight line connecting the connected third peak 3100a and third trough 3100b can form an angle with the axis of the first spacer segment 3000. When the straight line connecting the connected third peak 3100a and third trough 3100b forms an angle with the axis of the first spacer segment 3000, the connected third peak 3100a and third trough 3100b can have a third offset distance in the circumferential direction of the first spacer segment 3000. In this case, the third offset distance can be limited to be less than the straight-line distance between the connected third peak 3100a and third trough 3100b.

[0085] Unlike the structural design of the first end support segment 1000 and the second end support segment 2000, in this case, only some of the third peaks 3100a and third troughs 3100b are connected in the adjacent third support unit rings 3100; that is, there are unconnected third peaks 3100a and third troughs 3100b. Therefore, the structure formed by the first spacer support segment 3000 can be called a semi-closed-loop structure, meaning that the number of third connecting elements 3200 in the circumferential direction of the first spacer support segment 3000 is less than the number of third peaks 3100a or third troughs 3100b. This reduces the number of connected third peaks 3100a and third troughs 3100b, thus reducing the flexibility of the first spacer support segment 3000. The number of third peaks 3100a or third troughs 3100b can be 4 to 40, and the number of third support unit rings 3100 can be 2, 3, or other varying numbers. In addition, the number of third support unit rings 3100 can also be one, in which case the third peak 3100a and the third trough 3100b do not need to be connected.

[0086] The second spacer segment 4000 may include multiple fourth support unit rings 4100. Each fourth support unit ring 4100 has multiple fourth peaks 4100a and fourth troughs 4100b arranged sequentially in the circumferential direction, as shown in Figure 1. The fourth peak 4100a is the pointed portion of the fourth support unit ring 4100 facing upwards in Figure 1, and the fourth trough 4100b is the pointed portion of the fourth support unit ring 4100 facing downwards in Figure 1. The multiple fourth support unit rings 4100 are arranged along the axial direction of the second spacer segment 4000, and some of the fourth peaks 4100a and fourth troughs 4100b in adjacent fourth support unit rings 4100 are connected. For example, adjacent fourth peaks 4100a and fourth troughs 4100b are connected by a fourth connecting element 4200. The fourth connecting element 4200 may be at least one of a straight rod, an S-shaped rod, a V-shaped rod, an N-shaped rod, or an Ω-shaped rod.

[0087] In one embodiment, adjacent fourth support unit rings 4100 have multiple pairs of fourth peaks 4100a and fourth valleys 4100b that cooperate axially with each other in the second spacer support segment 4000 along the circumferential direction. Among these multiple pairs of axially cooperating fourth peaks 4100a and fourth valleys 4100b, the connected and unconnected pairs of fourth peaks 4100a and fourth valleys 4100b are sequentially spaced apart along the circumferential direction of the fourth support unit ring 4100. That is, connected fourth peaks 4100a and fourth valleys 4100b and unconnected fourth peaks 4100a and fourth valleys 4100b are arranged sequentially along the circumferential direction. In this case, the number of connected and unconnected fourth peaks 4100a and fourth valleys 4100b is the same. Alternatively, those skilled in the art can adjust the relative number of connected and unconnected fourth peaks 4100a and fourth valleys 4100b according to actual needs, which is not limited here.

[0088] Furthermore, the straight line connecting the connected fourth peak 4100a and fourth trough 4100b can be parallel to the axis of the second spacer segment 4000, or the straight line connecting the connected fourth peak 4100a and fourth trough 4100b can form an angle with the axis of the second spacer segment 4000. When the straight line connecting the connected fourth peak 4100a and fourth trough 4100b forms an angle with the axis of the first spacer segment 3000, the connected fourth peak 4100a and fourth trough 4100b can have a fourth offset distance in the circumferential direction of the first spacer segment 3000. In this case, the fourth offset distance can be limited to be less than the straight-line distance between the connected fourth peak 4100a and fourth trough 4100b.

[0089] Unlike the structural design of the first end support segment 1000 and the second end support segment 2000, in this case, only some of the fourth peaks 4100a and fourth valleys 4100b are connected in adjacent fourth support unit rings 4100; that is, there are unconnected fourth peaks 4100a and fourth valleys 4100b. Therefore, the structure formed by the second spacer support segment 4000 can be called a semi-closed-loop structure, meaning that the number of fourth connecting elements 4200 in the circumferential direction of the second spacer support segment 4000 is less than the number of fourth peaks 4100a or fourth valleys 4100b. This reduces the number of connected fourth peaks 4100a and fourth valleys 4100b, thus decreasing the compliance of the second spacer support segment 4000. The number of fourth peaks 4100a or fourth valleys 4100b can be 4 to 40, and the number of fourth support unit rings 4100 can be 1 to 3.

[0090] The middle support section 5000 may include multiple fifth support unit rings 5100. Each fifth support unit ring 5100 has multiple fifth peaks 5100a and fifth troughs 5100b arranged sequentially in the circumferential direction, as shown in Figure 1. The fifth peak 5100a is the pointed portion of the fifth support unit ring 5100 facing upwards in Figure 1, and the fifth trough 5100b is the pointed portion of the fifth support unit ring 5100 facing downwards in Figure 1. The multiple fifth support unit rings 5100 are arranged along the axial direction of the middle support section 5000, and some of the fifth peaks 5100a in adjacent fifth support unit rings 5100 are connected. For example, some of the fifth peaks 5100a in adjacent fifth support unit rings 5100 are connected by a fifth connecting element 5200. The fifth connecting element 5200 may be at least one of a straight rod, an S-shaped rod, a V-shaped rod, an N-shaped rod, or an Ω-shaped rod. Furthermore, the straight line connecting the connected fifth peaks 5100a can be parallel to the axis of the middle support section 5000, or the straight line connecting the connected fifth peaks 5100a can be at an angle to the axis of the middle support section 5000.

[0091] Compared to the structural design of the first spacer segment 3000 and the second spacer segment 4000, the number of connected fifth peaks 5100a in adjacent fifth support unit rings 5100 is further reduced, and the connections are all at the peak positions, no longer connecting peak and trough positions. Therefore, the structure formed by the middle support segment 5000 can be called an open ring structure. This further reduces the number of connections between the fifth peaks 5100a, thus lowering the flexibility of the middle support segment 5000.

[0092] The number of fifth peaks 5100a can be 4 to 40, and the number of fifth support unit rings 5100 can be 4 to 150. A larger number makes the middle support section 5000 the main section of the support structure 100. In one embodiment, by designing the position and number of connected fifth peaks 5100a in adjacent fifth support unit rings 5100, the middle support section 5000 can be constructed into a frame structure that is similar to a spiral in shape. For example, all connected fifth peaks 5100a are relatively misaligned in the circumferential direction, and this misalignment of connected fifth peaks 5100a is manifested as a gradual misalignment in the axial direction in a rotational direction, as shown in Figure 1.

[0093] In one embodiment, adjacent fifth support unit rings 5100 have multiple pairs of fifth peaks 5100a that cooperate axially in the middle support section 5000 along the circumferential direction. The number of non-connected fifth peaks 5100a pairs is an integer multiple of the number of connected fifth peaks 5100a pairs. For example, the multiple can be 3 times or more, thereby further reducing the number of connected fifth peaks 5100a and improving the flexibility of the middle support section 5000. Furthermore, referring to Figure 2, the fifth peaks 5100a connected in different adjacent fifth support units are staggered in the circumferential direction of the middle support section 5000. For example, when connected by the fifth connecting element 5200, the fifth connecting elements 5200 of adjacent fifth support unit rings 5100 may not all correspond to each other in the axial direction, or even none of them may correspond to each other in the axial direction. Thus, the aforementioned spiral-like frame structure can be constructed in the middle support section 5000, reducing stress concentration, reducing the risk of fracture of the support structure 100, ensuring the uniformity and structural stability of the support structure 100 in the axial direction, ensuring the uniformity of the release shape of the support structure 100, and improving fatigue resistance and long-term navigability.

[0094] When constructing a spiral frame structure, the fifth connecting elements 5200 between adjacent fifth support unit rings 5100 may not correspond axially to each other only in the axial direction between two adjacent fifth support unit rings 5100, but may correspond axially to each other between five fifth support unit rings 5100 separated by one ring, as shown in Figure 2. Alternatively, the fifth connecting elements 5200 between adjacent fifth support unit rings 5100 may not correspond axially to any other fifth connecting elements 5200 at all, or may correspond only to some of the other fifth connecting elements 5200; this is not limited here.

[0095] Referring again to Figures 3 and 4, in the structural design shown in Figure 3, the peak width 5000a of the fifth peak 5100a is the same as the stent width 5000b of the fifth stent unit ring 5100, i.e., L1 equals L2. Finite element analysis reveals that the stress concentration point 5000c of this stent structure 100 under stress in the blood vessel is inside the fifth peak 5100a. Finite element analysis also shows that the fatigue safety factor of the stent structure 100 at this point is 5.62.

[0096] As shown in Figure 4, when the peak width 5000a of the fifth peak 5100a is greater than the stent width 5000b of the fifth stent unit ring 5100, that is, L3 is greater than L4. In one embodiment, the peak width 5000a of the fifth peak 5100a can be limited to 1.1 to 3 times the stent width 5000b of the fifth stent unit ring 5100. Similarly, finite element analysis shows that the stress concentration location 5000c of the stent structure 100 under stress in the blood vessel is distributed to both sides of the fifth peak 5100a, which significantly reduces stress concentration and improves the overall fatigue resistance of the stent structure 100. Finite element analysis shows that the improved stent structure 100 increases the fatigue safety factor from 5.62 to 6.94, improving fatigue resistance by approximately 23.5%.

[0097] The support structure 100 can be laser-engraved. The metal tubing is laser-engraved into the designed support structure 100, and then heat-treated to achieve the required dimensions. The metal tubing is a highly resilient shape-memory polymer or metal material, such as nickel-titanium alloy, cobalt-chromium alloy, or stainless steel. A developing element 6000 can be installed on the support structure 100. For example, the developing element 6000 can be located at both ends of the support structure 100, specifically at least one of the first end support segment 1000 and the second end support segment 2000. The developing element 6000 can be fixed to the support structure 100 by interference fit or laser welding. The developing element 6000 can be made of X-ray-non-transmissive materials, such as tantalum, gold, platinum-tungsten alloy, or platinum-iridium alloy.

[0098] The first end support segment 1000 is connected to the end of the first spacer support segment 3000, wherein a portion of the first trough 1100b of the first support unit ring 1100 located at the end of the first end support segment 1000 is connected to a portion of the third peak 3100a of the third support unit ring 3100 located at the end of the first spacer support segment 3000. The second end support segment 2000 is connected to the end of the second spacer support segment 4000, wherein a portion of the second peak 2100a of the second support unit ring 2100 located at the end of the second end support segment 2000 is connected to a portion of the fourth trough 4100b of the fourth support unit ring 4100 located at the end of the second spacer support segment 4000.

[0099] The first spacer segment 3000 and the second spacer segment 4000 are respectively connected to both ends of the middle support segment 5000. A portion of the third trough 3100b of the third support unit ring 3100 located at the end of the first spacer segment 3000 is connected to a portion of the fifth peak 5100a of the fifth support unit ring 5100 located at the end of the middle support segment 5000. Similarly, a portion of the fourth peak 4100a of the fourth support unit ring 4100 located at the end of the second spacer segment 4000 is connected to a portion of the fifth trough 5100b of the fifth support unit ring 5100 located at the end of the middle support segment 5000. Furthermore, the aforementioned portion of the fifth peak 5100a is limited to not simultaneously connecting to the third trough 3100b and the fifth peak 5100a of other fifth support unit rings in the middle support segment. Likewise, the aforementioned portion of the fifth trough 5100b is not simultaneously connected to the fourth peak 4100a and the fifth trough 5100b of other fifth support unit rings in the middle support segment. Similarly, it can reduce stress concentration in the support structure 100 when under stress, ensure uniform stress distribution in the support structure 100, and improve the fatigue resistance and long-term ductility of the support structure 100.

[0100] This application provides a medical stent, which includes a stent structure 100. At least a portion of the surface of the stent structure 100 is provided with a polymer layer 200, and at least a portion of the surface of the polymer layer 200 is provided with a drug coating 300. The polymer layer 200 and the drug coating 300 can be sprayed onto one side, multiple sides, or completely cover the stent structure 100.

[0101] This application provides a method for preparing a medical stent, the method comprising the following steps: dissolving a first polymer in a first organic solvent to obtain a first solution, and depositing the first solution on the surface of a stent structure 100 to form a polymer layer 200. Dissolving a second polymer and a pharmaceutically active ingredient in a second organic solvent to obtain a second solution, and depositing the second solution on the surface of the polymer layer 200 to form a drug coating 300.

[0102] For example, after dissolving the first polymer in a first organic solvent to obtain a clear, transparent, and homogeneous first solution, the first solution can be loaded into the syringe of a drug spraying machine and used to perform a bottom coat spraying on the surface of the support structure 100 to obtain a polymer layer 200. After dissolving the second polymer and the active pharmaceutical ingredient in a second organic solvent to obtain a clear, transparent, and homogeneous second solution, the second solution can be loaded into the syringe of a drug spraying machine and used to perform a top coat spraying on the surface of the polymer layer 200 to obtain a drug coating layer 300.

[0103] The polymer layer 200 serves as an intermediary layer to bond the stent structure 100 to the drug coating 300. This improves the adhesion of the drug coating 300, reduces drug loss during stent placement and delivery, and prevents distal embolism caused by drug coating 300 detachment. The drug coating 300, applied to the surface of the stent structure 100, inhibits smooth muscle cell proliferation and migration, reduces intravascular restenosis, and improves late-stage patency. Therefore, the combined use of the polymer layer 200 and the drug coating 300 reduces both the drug release rate and the dosage, ensuring the safety of the organism.

[0104] The first polymer includes at least one selected from polymethyl methacrylate, polyethyl methacrylate, polybutyl methacrylate, n-butyl acrylate, and polyethyl acrylate. The first or second organic solvent includes at least one selected from methanol, ethanol, acetone, butanone, tetrahydrofuran, and cyclohexanone. The second polymer includes at least one selected from polyvinylidene fluoride-hexafluoropropylene copolymer, polytetrafluoroethylene, fluorinated polyethylene-propylene copolymer, polyhexafluoropropylene, polytetrafluoropropylene-hexafluoropropylene copolymer, polyhexafluoropropylene-ethylene-ethylene copolymer, polyhexafluoroethylene-tetrafluoroethylene copolymer, and polyvinylidene fluoride-trifluoroethylene copolymer. The active pharmaceutical ingredient includes at least one selected from antiproliferative drugs, anticoagulants, and anti-inflammatory drugs, such as paclitaxel, sirolimus and its derivatives, heparin and its analogues, actinomycin, mitomycin, argatroban, dextran, hirudin, colchicine, etc.

[0105] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0106] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the scope of protection of this application. Therefore, the scope of protection of this patent application should be determined by the appended claims.

Claims

1. A stent structure, characterized by, The support structure includes: Mid-section support; The first spacer support segment and the second spacer support segment are respectively connected to both ends of the middle support segment. A first end support segment and a second end support segment, wherein the first end support segment is connected to the end of the first spacer support segment, and the second end support segment is connected to the end of the second spacer support segment; At least one of the first end support segment and the second end support segment has a first frame flexibility, at least one of the first spacer support segment and the second spacer support segment has a second frame flexibility, and the middle support segment has a third frame flexibility. The first frame flexibility is less than the second frame flexibility, and the second frame flexibility is less than the third frame flexibility.

2. The stent structure of claim 1, wherein The first end support segment includes a plurality of first support unit rings. Each first support unit ring has a plurality of first peaks and first troughs arranged sequentially in the circumferential direction. The plurality of first support unit rings are arranged along the axial direction of the first end support segment. The first peak and first trough that are closest in axial distance among adjacent first support unit rings are connected.

3. The stent structure of claim 1, wherein The first wave crest and the first wave trough are connected by a first connecting element.

4. The stent structure of claim 3, wherein, The straight line connecting the first wave crest and the first wave trough is parallel to the axis of the first end support segment.

5. The stent structure of claim 3, wherein The straight line connecting the first peak and the first trough forms an angle with the axis of the first end support segment.

6. The stent structure of claim 5, wherein, The straight line connecting the first peak and the first trough is at an angle to the axis of the first end support segment, such that the connected first peak and the first trough have a first offset distance in the circumferential direction of the first end support segment, and the first offset distance is less than the straight line distance between the connected first peak and the first trough.

7. The stent structure of claim 3, wherein The first connecting element is at least one of a straight rod, an S-shaped rod, a V-shaped rod, an N-shaped rod, or an Ω-shaped rod.

8. The stent structure of claim 1, wherein, The second end support segment includes a plurality of second support unit rings. The second support unit rings have a plurality of second peaks and second troughs arranged sequentially in the circumferential direction. The plurality of second support unit rings are arranged along the axial direction of the second end support segment. The second peak and the second trough that are closest in axial distance among adjacent second support unit rings are connected.

9. The stent structure of claim 8, wherein, The adjacent second peaks and second troughs are connected by a second connecting element.

10. The support structure according to claim 9, characterized in that, The straight line connecting the second peak and the second trough is parallel to the axis of the second end support segment.

11. The support structure according to claim 9, characterized in that, The straight line connecting the second peak and the second trough forms an angle with the axis of the second end support segment.

12. The support structure according to claim 11, characterized in that, The straight line connecting the second peak and the second trough is at an angle to the axis of the second end support segment, such that the connected second peak and the second trough have a second offset distance in the circumferential direction of the second end support segment, the second offset distance being less than the straight distance between the connected second peak and the second trough.

13. The support structure according to claim 9, characterized in that, The second connecting element is at least one of a straight rod, an S-shaped rod, a V-shaped rod, an N-shaped rod, or an Ω-shaped rod.

14. The support structure according to claim 1, characterized in that, The first spacer segment includes multiple third support unit rings. Each third support unit ring has multiple third peaks and third troughs arranged sequentially in the circumferential direction. The multiple third support unit rings are arranged along the axial direction of the first spacer segment. The third peaks and third troughs of adjacent third support unit rings that are closest in axial distance are connected.

15. The support structure according to claim 14, characterized in that, The adjacent third peak and the third trough are connected by a third connecting element.

16. The support structure according to claim 15, characterized in that, The straight line connecting the third wave peak and the third wave trough is parallel to the axis of the first spacer segment.

17. The support structure according to claim 15, characterized in that, The straight line connecting the third peak and the third trough forms an angle with the axis of the first spacer segment.

18. The support structure according to claim 17, characterized in that, The straight line connecting the connected third peak and the third trough forms an angle with the axis of the first spacer segment, such that the connected third peak and the third trough have a third offset distance in the circumferential direction of the first spacer segment, the third offset distance being less than the straight-line distance between the connected third peak and the third trough.

19. The support structure according to claim 15, characterized in that, The third connecting element is at least one of a straight rod, an S-shaped rod, a V-shaped rod, an N-shaped rod, or an Ω-shaped rod.

20. The support structure according to claim 1, characterized in that, The second spacer segment includes a plurality of fourth support unit rings. Each fourth support unit ring has a plurality of fourth peaks and fourth valleys arranged sequentially in the circumferential direction. The plurality of fourth support unit rings are arranged along the axial direction of the second spacer segment. The fourth peaks and fourth valleys of adjacent fourth support unit rings that are closest in axial distance are connected.

21. The support structure according to claim 20, characterized in that, The adjacent fourth peak and the fourth trough are connected by a fourth connecting element.

22. The support structure according to claim 21, characterized in that, The straight line connecting the fourth peak and the fourth trough is parallel to the axis of the second spacer segment.

23. The support structure according to claim 21, characterized in that, The straight line connecting the fourth peak and the fourth trough forms an angle with the axis of the second spacer segment.

24. The support structure according to claim 23, characterized in that, The straight line connecting the connected fourth peak and the fourth trough forms an angle with the axis of the second spacer segment, such that the connected fourth peak and the fourth trough have a fourth offset distance in the circumferential direction of the second spacer segment, the fourth offset distance being less than the straight-line distance between the connected fourth peak and the fourth trough.

25. The support structure according to claim 21, characterized in that, The fourth connecting element is at least one of a straight rod, an S-shaped rod, a V-shaped rod, an N-shaped rod, or an Ω-shaped rod.

26. The support structure according to claim 1, characterized in that, The central support section includes multiple fifth support unit rings. Each fifth support unit ring has multiple fifth peaks and fifth troughs arranged sequentially in the circumferential direction. The multiple fifth support unit rings are arranged along the axial direction of the central support section, and the fifth peaks of adjacent fifth support unit rings with the closest axial distance are connected.

27. The support structure according to claim 26, characterized in that, The fifth peaks in adjacent fifth support unit rings are connected by a fifth connecting element.

28. The support structure according to claim 27, characterized in that, The straight line connecting the connected fifth wave peaks is parallel to the axis of the middle support section.

29. The support structure according to claim 27, characterized in that, The straight line connecting the connected fifth wave peaks forms an angle with the axis of the middle support segment.

30. The support structure according to claim 27, characterized in that, The fifth connecting element is at least one of a straight rod, an S-shaped rod, a V-shaped rod, an N-shaped rod, or an Ω-shaped rod.

31. The support structure according to claim 1, characterized in that, The adjacent third support unit rings have multiple pairs of third peaks and third valleys that cooperate with each other axially in the first spaced support segment along the circumferential direction. The multiple pairs of third peaks and third valleys that are connected or not connected are arranged sequentially at intervals in the circumferential direction of the third support unit rings.

32. The support structure according to claim 1, characterized in that, The adjacent fourth support unit rings have multiple pairs of fourth peaks and fourth valleys that cooperate with each other axially in the second spaced support segment along the circumferential direction. The multiple pairs of fourth peaks and fourth valleys that are connected or not connected are arranged sequentially at intervals in the circumferential direction of the fourth support unit rings.

33. The support structure according to claim 1, characterized in that, Adjacent fifth support unit rings have multiple pairs of fifth peaks that cooperate axially in the middle support section along the circumferential direction. The number of non-connected fifth peak pairs is an integer multiple of the number of connected fifth peak pairs. The connected fifth peaks in different adjacent fifth support units are staggered in the circumferential direction of the middle support section.

34. The support structure according to claim 1, characterized in that, The first end support segment includes a plurality of first support unit rings. Each first support unit ring has a plurality of first peaks and first troughs arranged sequentially in the circumferential direction. The plurality of first support unit rings are arranged along the axial direction of the first end support segment. The first peak and first trough that are closest in axial distance among adjacent first support unit rings are connected. The second end support segment includes a plurality of second support unit rings. The second support unit rings have a plurality of second peaks and second troughs arranged sequentially in the circumferential direction. The plurality of second support unit rings are arranged along the axial direction of the second end support segment. The second peak and the second trough that are closest in axial distance among adjacent second support unit rings are connected. The first spacer segment includes a plurality of third support unit rings. Each third support unit ring has a plurality of third peaks and third valleys arranged sequentially in the circumferential direction. The plurality of third support unit rings are arranged along the axial direction of the first spacer segment. The third peaks and third valleys of adjacent third support unit rings that are closest in axial distance are connected. The second spacer segment includes a plurality of fourth support unit rings. Each fourth support unit ring has a plurality of fourth peaks and fourth valleys arranged sequentially in the circumferential direction. The plurality of fourth support unit rings are arranged along the axial direction of the second spacer segment. The fourth peaks and fourth valleys of adjacent fourth support unit rings that are closest in axial distance are connected. The central support section includes multiple fifth support unit rings. Each fifth support unit ring has multiple fifth peaks and fifth troughs arranged sequentially in the circumferential direction. The multiple fifth support unit rings are arranged along the axial direction of the central support section, and the fifth peaks of adjacent fifth support unit rings with the closest axial distance are connected.

35. The support structure according to claim 34, characterized in that, A portion of the first trough of the first support unit ring located at the end of the first end support segment is connected to a portion of the third peak of the third support unit ring located at the end of the first interval support segment.

36. The support structure according to claim 34, characterized in that, A portion of the second wave peak of the second support unit ring located at the end of the second end support segment is connected to a portion of the fourth wave trough of the fourth support unit ring located at the end of the second spaced support segment.

37. The support structure according to claim 34, characterized in that, A portion of the third trough of the third support unit ring located at the end of the first spaced support segment is connected to a portion of the fifth peak of the fifth support unit ring located at the end of the middle support segment. The portion of the fifth peak does not simultaneously connect the portion of the third trough with the fifth peaks of other fifth support unit rings in the middle support segment.

38. The support structure according to claim 34, characterized in that, A portion of the fourth peak of the fourth support unit ring located at the end of the second spacer support segment is connected to a portion of the fifth valley of the fifth support unit ring located at the end of the middle support segment. The portion of the fifth valley does not simultaneously connect the portion of the fourth peak with the fifth valley of other fifth support unit rings in the middle support segment.

39. The support structure according to claim 1, characterized in that, The central support section includes multiple fifth support unit rings. Each fifth support unit ring has multiple fifth peaks and fifth troughs arranged sequentially in the circumferential direction. The width of the fifth peak is greater than the support width of the fifth support unit ring.

40. The support structure according to claim 39, characterized in that, The width of the fifth peak is 1.1 to 3 times the width of the fifth support unit ring.

41. A medical stent, characterized in that, The medical stent includes the stent structure as described in any one of claims 1-40, wherein at least a portion of the surface of the stent structure is provided with a polymer layer, and at least a portion of the surface of the polymer layer is provided with a drug coating.

42. A method for preparing the medical stent according to claim 41, characterized in that, The preparation method includes the following steps: A first polymer is dissolved in a first organic solvent to obtain a first solution, and the first solution is disposed on the surface of the support structure to form the polymer layer; A second solution is obtained by dissolving the second polymer and the active pharmaceutical ingredient in a second organic solvent, and the second solution is disposed on the surface of the polymer layer to form the drug coating.

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