Long-section peripheral vascular stent

Abstract

The utility model discloses a long-section peripheral vascular stent, which comprises a curved arc and a connecting arc, is used for treating diseases such as peripheral vascular stenosis below knees and the like, and solves the problems that the conventional stent is difficult to lead into peripheral vessels and lacks effective support. The stent has two states of a pressing and holding state and an expansion state with different section radiuses, is implanted into a peripheral vascular affected part in the pressing and holding state, and supports a blood vessel at the affected part in the expansion state. Sufficient radial yield strength is provided through a plurality of supporting rings so as to adapt to the characteristics that the peripheral blood vessel is large in elasticity and thick in outer base layer. And the stent is prepared from a degradable material, so that mechanical support required in the early stage of fusion is met, the stent also has relatively high strength and toughness, and the stent can be degraded in vivo, so that the use safety is greatly improved. Moreover, the pattern of the stent is optimized, so that the circumferential rotation phenomenon of the longer intravascular stent in the expansion process is improved, and the damage to the vascular wall in the implantation process is reduced to the greatest extent.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of interventional therapy, and particularly relates to a long-segment peripheral vascular stent. BACKGROUND

[0002] Peripheral arterial disease (PAD) is a vascular disease that affects more than 200 million people worldwide, and its most severe form, critical limb-threatening ischemia (CLTI), encompasses a range of severe symptoms such as occlusion of below-knee arteries, rest pain in the lower limbs due to insufficient blood supply, tissue damage, and even gangrene. The high morbidity and mortality rates caused by CLTI undoubtedly place a heavy burden on the medical system. Despite the huge medical expenses, the five-year survival rate of patients remains dismal, and it is particularly concerning that traditional treatment methods for CLTI-related below-knee artery (BTK) lesions have significant limitations. Although endovascular treatment methods such as POBA (percutaneous transluminal balloon angioplasty), DCB (drug-coated balloon), DES (drug-eluting stent), and debulking are widely used, these methods have certain limitations and cannot achieve ideal treatment results.

[0003] Below-knee artery (BTK) lesions are characterized by long lesions, small vessel diameters, severe calcification, and high severity, making them one of the difficulties of endovascular treatment of lower extremities. Existing endovascular treatments for BTK disease include POBA (percutaneous transluminal balloon angioplasty), DCB (drug-coated balloon), DES (drug-eluting stent), and debulking, but all have certain limitations. For local BTK lesions, DES stents improve primary patency rate, TLR rate, and limb salvage rate compared to POBA or BMS, reducing the risk of reintervention and amputation.

[0004] However, peripheral blood vessels have large elasticity and thick outer layers, and the blood vessels are elastic, requiring greater support from the stent. Moreover, the stenosis in peripheral blood vessels is longer, requiring a longer stent. Due to the increased length, the existing vascular stents are prone to uneven expansion. Practical new type content

[0005] The peripheral stent of the present application is used to treat diseases such as below-knee peripheral vascular stenosis, solves the problem that existing stents are difficult to be introduced into peripheral blood vessels and lack effective support, and through optimization of the pattern of the stent, the circumferential rotation phenomenon of the longer vascular stent during expansion is improved, and the damage to the blood vessel wall during implantation is minimized.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] The long-section peripheral blood vessel stent comprises a curved arc and a connecting arc; the curved arc is an axis-symmetrical arc, and the connecting arc comprises an arc-shaped part and a connecting part; the arc-shaped part is completely identical in shape with the curved arc, and the connecting part is arranged at one end outside the arc-shaped part and extends outward at the other end; the connecting arc and the curved arc are connected head to tail to form a closed support ring, the connecting arcs are distributed at intervals on the same support ring and are staggered on adjacent support rings; the adjacent support rings are directly connected to each other, thereby being connected into a tubular stent structure; in the support ring, the adjacent curved arcs and the arc-shaped parts on the same support ring and the curved arcs are all center-symmetrical patterns, and the connecting points are the rotation centers.

[0008] Further, in the connecting arc, the number of curved arcs at intervals between the adjacent connecting arcs on the same support ring is the same.

[0009] Further, in the connecting arc, the number of curved arcs at intervals between the adjacent connecting arcs on the same support ring is even, so that the adjacent connecting parts are located on both sides of the support ring.

[0010] Further, in the connecting arc, the adjacent connecting arcs on the adjacent support rings are staggered, so that the connecting parts are inclined to the axial direction.

[0011] Further, the connecting part is inclined relative to the connecting line (a-a line) of the rotation centers of the arc segments of the support ring, the included angles of the connecting parts on both sides of the support ring with the a-a line are the same, but the inclined directions of the connecting arcs on both sides of the support ring are opposite; and in the connecting part, the inclined angles of the array of connecting parts with the same inclined direction are the same.

[0012] The present application has at least the following beneficial effects:

[0013] The support ring connected by the arc units of different shapes has good compressibility and can be deformed in the circumferential direction, is especially suitable for peripheral blood vessels with longer length and more complex conditions, and improves the problem of uneven expansion of each part of the longer catheter; at the same time, the structure of the connecting arc also optimizes the connection between the support rings, can be moderately bent based on the blood vessel condition, and improves the smoothness of delivery; additionally, the support ring has high circumferential strength and overcomes the circumferential rotation phenomenon in the expansion process.

[0014] In addition, the present application uses a zinc alloy material as the main structure, which is non-toxic and has good tissue compatibility and blood compatibility, and the peripheral blood vessel stent made of the degradable zinc alloy material can meet the mechanical support required in the early fusion period, the mechanical properties meet the strength and toughness requirements of medical implant materials, and can be degraded in the body. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical features, objectives and effects of the embodiments of the present application or the prior art, the drawings needed in the description of the embodiments or the prior art will be briefly introduced. Obviously, the drawings described below are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0016] Figure 1 The structure of the arc in the present application is schematically shown.

[0017] Figure 2 The structure of the connecting arc in the present application is schematically shown.

[0018] Figure 3 The structure of the connecting state of the arc and the connecting arc in the present application is schematically shown.

[0019] Figure 4 The structure of the support ring in the present application is schematically shown.

[0020] Figure 5 The planar development of the present application is schematically shown.

[0021] Figure 6 The finite element simulation diagram of the present application after expansion is schematically shown.

[0022] Wherein: 1-support ring, 11-arc, 12-connecting arc, 121-arc part, 122-connection part. EMBODIMENTS

[0023] In order to have a clearer understanding of the technical features, objectives and effects of the present application, the specific embodiments of the present application will be described in detail with reference to the drawings. In the following description, it should be understood that the orientation or positional relationship indicated by "front", "rear", "upper", "lower", "left", "right", "vertical", "horizontal", "vertical", "horizontal", "top", "bottom", "inner", "outer", "head", "tail" and the like is based on the orientation or positional relationship shown in the drawings, and is constructed and operated in a particular orientation, only for the convenience of describing the present technical solution, and cannot be understood as indicating that the device or element must have a particular orientation, therefore it cannot be understood as a limitation of the present application.

[0024] It should be noted that, unless otherwise explicitly specified and limited, the terms such as "mounting", "connection", "connecting", "fixing", "setting" and the like should be interpreted in a broad sense, for example, can be fixed connection, or can be detachable connection, or can be integrated; can be mechanical connection, or can be electrical connection; can be directly connected, or can be indirectly connected through an intermediate medium, or can be the internal communication of two elements or the interaction relationship between two elements. When an element is referred to as "on" or "under" another element, the element can be "directly" or "indirectly" located on the other element, or one or more intervening elements can be present. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0025] In the following description, specific details are set forth in order to provide a thorough understanding of the embodiments of the present application for purposes of explanation and not limitation. However, it will be apparent to those skilled in the art that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices and methods are omitted so as not to obscure the description of the present application with unnecessary detail. Embodiment

[0026] A long-section peripheral vascular stent is formed by connecting a plurality of same curved arcs 11 and connecting arcs 12, and a closed support ring 1 is formed by the combination of the curved arcs 11 and the connecting arcs 12. A plurality of support rings 1 are connected to each other to form a hollow tubular structure. The stent has two states of a compression state and an expansion state with different cross-sectional radii. In the compression state, the stent is implanted in a peripheral vascular lesion, and in the expansion state, the stent supports the vascular lesion. The plurality of support rings 1 provide sufficient radial yield strength to adapt to the characteristics of the peripheral vascular elasticity and thick outer base layer. Moreover, the stent is made of degradable material, which not only meets the mechanical support required in the early fusion period, but also has high strength and toughness, and can be degraded in the body, greatly improving the safety of use.

[0027] Peripheral vessels are different from coronary vessels, and their elasticity is often greater and their length is longer. The vascular stents on the market are mainly designed for coronary vessels, and for peripheral vascular stents, they are mostly simply extended on the basis of coronary stents. However, for long-section peripheral vessels, the simple extension of coronary stents cannot fully meet the requirements of support strength and delivery flexibility.

[0028] In addition, the applicant finds that the prior art has a new technical problem that the stent is prone to circumferential rotation during the compression and expansion process; circumferential rotation refers to that the support ring 1 rotates in different degrees in the circumferential direction during the expansion of the support ring 1, which is not obvious in the coronary stent, and the longer the circumferential rotation is, the more obvious the circumferential rotation is for a long-segment stent. Moreover, during the twisting process, the circumferential rotation process promotes the adverse interaction between the arterial wall and the device, which may cause damage to the arterial wall and increase the risk of treatment failure.

[0029] It should be noted that the long segment here is longer than the coronary blood vessel, for example, the length of the coronary stent is generally 8-40 mm, while the length of the peripheral blood vessel stent can reach 170 mm, and the person skilled in the art can flexibly select stents of different length specifications based on the differences in use sites.

[0030] Preferably, the length of the long-segment peripheral blood vessel stent is 50-200 mm.

[0031] To avoid the above problems, different technical solutions are adopted in the present application.

[0032] The stent of the present application is connected by arc units, and the arc units have two different forms, namely curved arcs 11 and connecting arcs 12, as shown in Figure 1 The curved arc 11 is an axisymmetric arc, and the two ends of the curved arc 11 are directed to the same side, which is similar to a U-shaped or C-shaped arc unit. The two sides of the curved arc 11 can be opened, and the middle part of the curved arc 11 is a circular arc or an elliptical arc, which avoids stress concentration after opening and balances the stress.

[0033] As shown in Figure 3 The arc-shaped part 121 of the connecting arc 12 is exactly the same as the shape of the curved arc 11, and the connecting arc 12 and the curved arc 11 are connected at the ends to form a closed support ring 1. The arc-shaped part 121 of the connecting arc 12 and the curved arc 11 between adjacent curved arcs 11 form a center-symmetric figure, and the two are rotationally symmetric with the connecting point as the center, so that the support ring 1 is uniformly expanded in the circumferential direction.

[0034] The difference between the connecting arc 12 and the curved arc 11 is that the connecting arc 12 has a connecting part 122, as shown in Figure 2 The connecting part 122 is fixed in the middle part of the connecting arc 12 and extends outward, and the connecting parts 122 of the connecting arcs 12 on adjacent support rings 1 are connected to each other, so as to connect the support rings 1 into a tubular stent.

[0035] It should be noted that the side of the connecting part 122 of the connecting arc 12 extending outward is the side opposite to the opening direction of the connecting arc 12.

[0036] Further, the connecting arcs 12 are distributed at intervals on the same support ring 1 and staggered on adjacent support rings 1, avoiding interference in the process of compression and expansion and bending, and improving the flexibility of delivery.

[0037] Staggered distribution specifically, the connecting arcs 12 on adjacent support rings 1 are not in the same axial direction, and correspondingly, as shown in the planar development view, Figure 5 it can be seen that the connecting arcs 12 on adjacent support rings 1 are not on a horizontal line, and are separated by at least the width of an arc 11, so that the connecting portions 122 are inclined to the horizontal line, and the angles of inclination are the same.

[0038] Interval distribution specifically, the connecting arcs 12 on the same support ring 1 are distributed at intervals, as shown in the planar development view, Figure 4 the a-a line is a line connecting the connecting positions of the arc 11 and the connecting arc 12 in the planar development state, the a-a line is annular in use, the plane constructed by the a-a line is perpendicular to the axial direction, and in the planar development, Figure 4 the a-a line is a straight line, and adjacent support rings 1 on the same support ring 1 are separated by an even number of arcs 11, so that on the same support ring 1, the connecting arc 12 and the two closest connecting rings are located on the two sides of the a-a line, respectively, and the connecting portions 122 on the two sides of the connecting arc 12 are inclined in opposite directions, and the angles α and β between the extensions of the two connecting portions 122 and the a-a line are the same.

[0039] Of course, the end support ring 1 has no support ring 1 connected to the other side, so the number of arcs 11 separating adjacent support rings 1 on the end support ring 1 is an even number times that of the middle support ring 1, and there is no connecting portion 122 on the outward side.

[0040] Preferably, adjacent support rings 1 on the same support ring 1 are separated by 2 arcs 11, and adjacent support rings 1 on the end support ring 1 are separated by 4 arcs 11.

[0041] Additionally, since the connecting arcs 12 are uniformly distributed on both sides of the support ring 1, and the angles of inclination of the connecting portions 122 on both sides are different, clockwise or counterclockwise rotation will be limited by the connecting portions 122, improving the stability in the axial direction and reducing the occurrence of circumferential rotation.

[0042] Of course, the connecting portion 122 can be a straight line or a curve, and in this embodiment, a straight line is used as an example for illustration.

[0043] As shown in the planar development view, Figure 6 the circumferential support of the present embodiment has not undergone significant circumferential rotation, indicating that the structure of the present application effectively overcomes the occurrence of circumferential rotation. Further combining Figure 6It can be seen that the structure of the outer peripheral support is uniform in stress during expansion of each part, and there is no position of stress concentration, which shows that the combination structure of the curved arc 11 and the connecting arc 12 meets the requirement of uniform expansion and reduces the generation of defects.

Claims

1. A long-segment peripheral vascular stent, characterized in that: include: Curved arc, connecting arc; The curved arc is an axisymmetric arc, and the connecting arc includes an arc-shaped part and a connecting part. The arc-shaped part has the same shape as the curved arc, and one end of the connecting part is located on the outside of the arc-shaped part, while the other end extends outward. The connecting arcs and curved arcs are connected end to end to form a closed support ring. The connecting arcs are distributed at intervals on the same support ring and staggered on adjacent support rings. Adjacent support rings are directly connected to each other, thereby forming a tubular support structure. In the support ring, adjacent curved arcs and arc-shaped portions on the same support ring, as well as between curved arcs, are all centrally symmetrical figures, and the connection point is the center of rotation.

2. The long-segment peripheral vascular stent according to claim 1, characterized in that: In the connecting arc, the number of curved arcs between adjacent connecting arcs on the same support ring is the same.

3. The long-segment peripheral vascular stent according to claim 2, characterized in that: In the connecting arc, the number of curved arcs between adjacent connecting arcs on the same support ring is an even number, so that the adjacent connecting parts are located on both sides of the support ring.

4. The long-segment peripheral vascular stent according to claim 1, characterized in that: In the connecting arc, the connecting arcs located on adjacent support rings are staggered, so that the connecting part is inclined to the axial direction.

5. A long-segment peripheral vascular stent according to claim 4, characterized in that: The connecting part is inclined relative to the aa line where the rotation center of each arc segment of the support ring is located, and the angle between the connecting parts on both sides of the support ring and the aa line is the same, but the inclination direction of the connecting arcs on both sides of the support ring is opposite.

6. A long-segment peripheral vascular stent according to claim 5, characterized in that: In the connecting parts, the tilt angles of the array connecting parts with the same tilt direction are all the same.

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