Intravascular stent with variable stiffness structure

Abstract

The invention discloses an intravascular stent with a variable stiffness structure, and belongs to the technical field of vascular intervention medical instruments, the intravascular stent comprises an intravascular stent body, the intravascular stent body comprises a plurality of stent ring assemblies distributed in the axial direction, and each stent ring assembly comprises a first stent ring assembly and a second stent ring assembly; the first support ring assemblies are symmetrically arranged on the two sides of the second support ring assembly, and the first support ring assemblies and the second support ring assembly are connected through first connecting ribs. By the adoption of the structure, by changing the axial width of the stent rings and the number of the supporting units and connecting the stent rings through the connecting ribs of different forms, the stent can present differential mechanical behaviors when adapting to the stress and deformation requirements of different lesion segments, the supporting performance of the stent on narrow blood vessels is improved through the middle part of the stent, and the supporting effect of the stent is improved. During axial bending, the two ends are better attached to the blood vessel wall, and damage of the stent to the blood vessel wall is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of vascular interventional medical devices, and particularly to a vascular stent with a variable stiffness structure. Background Art

[0002] The coronary artery is the main blood vessel that supplies blood to the heart. When atherosclerosis occurs in the coronary artery, the narrowed coronary artery restricts blood flow to the myocardium, resulting in myocardial ischemia. Vascular stents are an important means for treating diseases such as coronary artery stenosis, used to dilate the narrowed or blocked coronary artery, and can quickly restore blood flow and relieve symptoms such as myocardial ischemia.

[0003] Coronary stent intervention surgery is the preferred method for treating coronary artery stenosis. Most current stents adopt a design of repeating the same stent ring and connecting rib structure, which makes the flexibility of the proximal and distal ends of the stent the same and the radial strength the same after expansion. However, most atherosclerotic plaques in narrowed blood vessels are thick in the middle and thin at both ends. Therefore, after the stent expands and rebounds in the narrowed blood vessel, there will inevitably be a severe rebound at the position corresponding to the plaque and the dogbone effect of the two ends warping up, especially for narrowed blood vessels rich in calcified lesions, the dogbone effect is more obvious. At the same time, for lesions occurring at the curved blood vessel position, excessive opening of the two ends of the stent will cause excessive damage to the blood vessel. Complications such as in-stent restenosis, early or late thrombosis in the stent caused by the mismatch between the structure and mechanical properties of the stent and the blood vessel seriously affect the treatment effect. Summary of the Invention

[0004] The purpose of the present invention is to provide a vascular stent with a variable stiffness structure. By setting stent rings and connecting ribs with different structures, the vascular stent is designed into a new structure that is uneven as a whole and whose stiffness can dynamically change with deformation, and can adapt to the differences in the lesion morphology and material properties to produce appropriate deformation and stress.

[0005] To achieve the above purpose, the present invention provides a vascular stent with a variable stiffness structure, including a vascular stent body. The vascular stent body includes a plurality of stent ring components distributed axially. The stent ring components include a first stent ring component and a second stent ring component. The first stent ring component is symmetrically arranged on both sides of the second stent ring component, and the first stent ring component is connected to the second stent ring component through a first connecting rib.

[0006] Preferably, the first stent ring component includes two groups of first stent rings and second stent rings connected in sequence. The second stent ring component includes four groups of third stent rings connected in sequence. The first stent ring, the second stent ring, and the third stent ring are all in a sine wave shape and are all composed of a plurality of V-shaped support units connected end to end. After connection, the waveform support ring forms a plurality of wave crest and wave trough structures.

[0007] Preferably, the two first support rings are connected by a second connecting rib, and the wave crests are opposite to each other, presenting an upper and lower mirror-symmetrical structure. One side of the second support ring is connected to the first support ring by the second connecting rib, and the other side is connected to the third support ring by the first connecting rib. Between the first support ring and the second support ring and between the second support ring and the third support ring, the wave crests are opposite to each other. Adjacent third support rings are connected by the first connecting rib, and the wave crests are opposite to each other, presenting an upper and lower mirror-symmetrical structure.

[0008] Preferably, one end of the second connecting rib is connected to the right side of the first support ring near the wave crest, and the other end is connected to the left side of the adjacent first support ring near the wave crest; or one end of the second connecting rib is connected to the wave crest of the first support ring, and the other end is connected to the wave crest of the second support ring.

[0009] Preferably, one end of the first connecting rib is connected to the wave crest of the second support ring, and the other end is connected to the wave crest of the third support ring; or one end of the first connecting rib is connected to the right side of the third support ring near the wave crest, and the other end is connected to the left side of the adjacent third support ring near the wave crest.

[0010] Preferably, the first connecting rib and the second connecting rib are arranged non-uniformly and alternately along the axial direction of the blood vessel stent body, and are uniformly distributed along the circumferential direction of the blood vessel stent body.

[0011] Preferably, both the first connecting rib and the second connecting rib are one of the S-shaped, I-shaped, U-shaped, V-shaped, W-shaped, and N-shaped structures.

[0012] Preferably, the axial width of the second support ring is smaller than the axial width of the first support ring and greater than or equal to the axial width of the third support ring.

[0013] Preferably, the number of V-shaped support units in the first support ring is the same as that in the second support ring, and the number of V-shaped support units in the third support ring is twice that in the second support ring.

[0014] Preferably, the first support ring, the second support ring, and the third support ring are all uniformly distributed along the circumferential direction of the blood vessel stent body.

[0015] Preferably, the blood vessel stent body is formed by one-time laser cutting of a medical zinc alloy tube.

[0016] Therefore, the present invention adopts the above-mentioned blood vessel stent with a variable stiffness structure, and specifically has the following beneficial effects:

[0017] (1) The vascular stent of the present invention obtains a non-uniform variable stiffness stent structure by changing the axial width of the stent rings, the number of support units, and connecting the stent rings with connecting ribs in different forms, enabling the stent to exhibit different mechanical behaviors when adapting to the force and deformation requirements of different diseased segments. By improving the support for the stenotic blood vessel in the middle part of the stent, when axially bent, both ends fit the blood vessel wall better, reducing the damage of the stent to the blood vessel wall and effectively improving the radial support, flexibility, and wall apposition of the stent.

[0018] (2) The stent rings are in the shape of a traditional sine wave. By setting stent rings with different axial widths and increasing the number of support units at the same time, the radial support of the stent for the stenotic blood vessel is improved, and by reducing the axial distribution width of the stent ring structure, the longitudinal flexibility of the stent is enhanced.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Description of the Drawings

[0020] Figure 1 is a schematic structural diagram of an embodiment of the present invention;

[0021] Figure 2 is a schematic structural diagram of the vascular stent of the embodiment of the present invention after being unfolded along the axial plane;

[0022] Reference Signs

[0023] 1. Vascular stent body; 2. First stent ring assembly; 21. First stent ring; 22. Second stent ring; 3. Second stent ring assembly; 31. Third stent ring; 4. First connecting rib; 5. Second connecting rib. Detailed Embodiments

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations. In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0025] Embodiment

[0026] Refer toFigure 1-2 , the present invention provides a vascular stent with a variable stiffness structure, including a vascular stent body 1, which is formed by laser cutting a medical zinc alloy tube in one step. The vascular stent body 1 includes a plurality of stent ring assemblies distributed along the axial direction. The stent ring assembly includes a first stent ring assembly 2 and a second stent ring assembly 3. The first stent ring assembly 2 is symmetrically arranged on both sides of the second stent ring assembly 3, and the first stent ring assembly 2 and the second stent ring assembly 3 are connected by a first connecting rib 4.

[0027] Specifically, the first stent ring assembly 2 includes two groups of first stent rings 21 connected in sequence and one group of second stent rings 22. The second stent ring assembly 3 includes four groups of third stent rings 31 connected in sequence. The first stent rings 21, the second stent rings 22, and the third stent rings 31 are all in a sine wave shape and are all composed of a plurality of V-shaped support units connected end to end. The connected waveform support rings form a plurality of peak and valley structures. It should be noted that in actual applications, the number and position of the stent ring structures and the selection of the connecting ribs between the stent rings can be adjusted adaptively according to needs.

[0028] Specifically, the first stent ring 21 is composed of 6 V-shaped support units connected end to end, and the axial width of the V-shaped support unit is 1.75 mm. The second stent ring 22 is composed of 6 V-shaped support units, and the axial width of the V-shaped support unit is 1.20 mm. The third stent ring 31 is composed of 12 V-shaped support units, and the axial width of the V-shaped support unit is 0.8 mm. The connected waveform support rings form a plurality of peak and valley structures through the V-shaped support units. It should be noted that in actual applications, the specific dimensions of the first stent ring 21, the second stent ring 22, and the third stent ring 31 can all be adjusted adaptively according to needs. At positions where a high bending degree of the stent is required, the axial width of the stent ring structure can be reduced. At positions with a large load on the stenosis, the number of support units can be increased at the same time. At positions where a high bending degree of the stent is required, the axial width of the stent ring structure can be reduced, and at the same time, the second connecting rib 5 structure is used to connect the stent rings, thereby adjusting the supportability and flexibility of the vascular stent according to the lesion.

[0029] Specifically, the two first stent rings 21 are connected by a second connecting rib 5, and the peaks are opposite to each other, showing an up-and-down mirror-symmetric structure. One side of the second stent ring 22 is connected to the first stent ring 21 by a second connecting rib 5, and the other side is connected to the third stent ring 31 by a first connecting rib 4. Between the first stent ring 21 and the second stent ring 22 and between the second stent ring 22 and the third stent ring 31, the peaks are opposite to each other. The adjacent third stent rings 31 are connected by a first connecting rib 4, and the peaks are opposite to each other, showing an up-and-down mirror-symmetric structure.

[0030] Specifically, one end of the second connecting rib 5 is connected to the right side of the first support ring 21 near the wave crest, and the other end is connected to the left side of the adjacent first support ring 21 near the wave crest; or one end of the second connecting rib 5 is connected to the wave crest of the first support ring 21, and the other end is connected to the wave crest of the second support ring 22.

[0031] Specifically, one end of the first connecting rib 4 is connected to the wave crest of the second support ring 22, and the other end is connected to the wave crest of the third support ring 31; or one end of the first connecting rib 4 is connected to the right side of the third support ring 31 near the wave crest, and the other end is connected to the left side of the adjacent third support ring 31 near the wave crest.

[0032] Specifically, the first connecting rib 4 is in the shape of "I" with an axial length of 0.3 mm, and the second connecting rib 5 is in the shape of "S" with an axial length of 0.35 mm. The "I"-shaped connecting rib structure has strong radial support force but poor longitudinal flexibility, while the "S"-shaped connecting rib structure has good longitudinal flexibility but poor radial support force. Therefore, by adopting these two different connecting rib structures and cooperating with different-shaped support ring structures, different mechanical behaviors can be presented when meeting the force and deformation requirements of different diseased segments. At the same time, the first connecting rib 4 and the second connecting rib 5 are arranged non-uniformly and alternately along the axis of the vascular stent body 1, and are evenly distributed along the circumference of the vascular stent body 1. It should be noted that the structures of the first connecting rib 4 and the second connecting rib 5 can be selected according to actual needs, and their distribution positions along the axis can be adjusted according to the disease.

[0033] Specifically, the first support ring 21, the second support ring 22, and the third support ring 31 are all evenly distributed along the circumference of the vascular stent body 1. It should be noted that the distribution positions of the first support ring 21, the second support ring 22, and the third support ring 31 along the axis can be adjusted according to the disease.

[0034] Specifically, the inner diameter of the vascular stent body 1 is 1.8 mm, the outer diameter is 2 mm, the wall thickness is 0.1 mm, and the length is 15.6 mm. It should be noted that in actual applications, the specific dimensions of the vascular stent body 1 can be adjusted adaptively according to needs.

[0035] Therefore, the present invention adopts the above-mentioned vascular stent with a variable stiffness structure. By setting support rings and connecting ribs with different structures, the vascular stent is designed into a new structure that is uneven as a whole and whose stiffness can change dynamically with deformation, and can adapt to the differences in the diseased morphology and material properties to produce appropriate deformation and stress.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements do not cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A vascular stent with a variable stiffness structure, characterized in that: It includes a vascular stent body, and the vascular stent body includes a plurality of stent ring assemblies distributed axially. The stent ring assemblies include a first stent ring assembly and a second stent ring assembly. The first stent ring assembly is symmetrically arranged on both sides of the second stent ring assembly, and the first stent ring assembly and the second stent ring assembly are connected by a first connecting rib.

2. The vascular stent with a variable stiffness structure according to claim 1, characterized in that: The first stent ring assembly includes two groups of first stent rings and second stent rings connected in sequence. The second stent ring assembly includes four groups of third stent rings connected in sequence. The first stent rings, the second stent rings, and the third stent rings are all in a sine wave shape and are all composed of a plurality of V-shaped support units connected end to end. After connection, the waveform support rings form a plurality of peak and valley structures.

3. The vascular stent with a variable stiffness structure according to claim 2, characterized in that: Two of the first stent rings are connected by a second connecting rib, and the peaks are opposite to each other, presenting an up-and-down mirror-symmetrical structure. One side of the second stent ring is connected to the first stent ring by the second connecting rib, and the other side is connected to the third stent ring by the first connecting rib. Between the first stent ring and the second stent ring and between the second stent ring and the third stent ring, the peaks are opposite to each other. Adjacent third stent rings are connected by the first connecting rib, and the peaks are opposite to each other, presenting an up-and-down mirror-symmetrical structure.

4. The vascular stent with a variable stiffness structure according to claim 3, characterized in that: One end of the second connecting rib is connected to the right side of the first stent ring near the peak, and the other end is connected to the left side of the adjacent first stent ring near the peak; or one end of the second connecting rib is connected to the peak of the first stent ring, and the other end is connected to the peak of the second stent ring.

5. The vascular stent with a variable stiffness structure according to claim 3, characterized in that: One end of the first connecting rib is connected to the peak of the second stent ring, and the other end is connected to the peak of the third stent ring; or one end of the first connecting rib is connected to the right side of the third stent ring near the peak, and the other end is connected to the left side of the adjacent third stent ring near the peak.

6. The vascular stent with a variable stiffness structure according to claim 3, characterized in that: The first connecting rib and the second connecting rib are arranged non-uniformly and alternately along the axis of the vascular stent body and are uniformly distributed along the circumference of the vascular stent body.

7. The vascular stent with a variable stiffness structure according to claim 3, wherein: Both the first connecting rib and the second connecting rib are one of the S-shaped, I-shaped, U-shaped, V-shaped, W-shaped, and N-shaped structures.

8. The vascular stent with a variable stiffness structure according to claim 2, characterized in that: The axial width of the second stent ring is less than the axial width of the first stent ring and greater than or equal to the axial width of the third stent ring.

9. The vascular stent with a variable stiffness structure according to claim 2, wherein: The number of V-shaped support units of the first stent ring is the same as that of the second stent ring, and the number of V-shaped support units of the third stent ring is twice that of the second stent ring.

10. The vascular stent with a variable stiffness structure according to claim 2, characterized in that: The first stent rings, the second stent rings, and the third stent rings are all uniformly distributed along the circumference of the vascular stent body.

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