Spherical expansion conical support

Abstract

The invention provides a ball expansion conical support which comprises a design unit and a connecting unit, the design unit comprises a plurality of support rods and a plurality of wave heads, the support rods are arranged at intervals, and every two adjacent support rods are sequentially connected in series through each wave head to form an annular structure; the number of the design units is multiple, the connecting unit is connected between the wave heads of every two adjacent design units, the radial supporting force Fn of the nth design unit from the near end to the far end of the stent is smaller than the radial supporting force Fn-1 of the (n-1) th design unit, and n is larger than or equal to 2 and smaller than or equal to 200. The radial supporting force of the stent from the near end to the far end is set, so that the expanded stent retracts to different degrees at different positions under the action of the return pressure of a blood vessel in a lesion area, and the conical stent which is very matched with the blood vessel in taper shape is formed. The support and the conical pipeline have good fitting degree.

Description

Technical Field

[0001] The present invention relates to the field of medical devices, in particular to a conical stent, and more particularly to an adaptive ball-expanding conical stent. Background Art

[0002] There are many lumen structures in the human body, including blood vessels, bile ducts, pancreas, esophagus, trachea, urethra and intestines. These lumen structures are prone to lesions under certain conditions, leading to stenosis or occlusion of the lumen, which in turn causes a series of safety hazards. For example, vascular ischemia caused by vascular stenosis or occlusion is an important cause of threat to human health, and stent implantation is currently an important means of treating stenosis or occlusion of the lumen. Balloon-expandable stents are implanted at the lesion site by expanding the balloon to support the stenotic occluded lumen and keep the lumen patency. However, some lumens in the human body, such as the femoral artery and the popliteal artery, have significant conical features, and the diameter of the proximal end is significantly larger than the diameter of the distal end. As the length of the lumen increases, the taper effect becomes more and more significant, and the difference in diameter between the proximal and distal ends becomes more and more obvious.

[0003] At present, the balloon-expandable stents commonly used in clinical practice for conical vascular lesions are still of round and straight design. However, there are still some problems with the round and straight balloon-expandable stents in practical applications. For example, when selecting a vascular stent, if the stent is selected based on the proximal blood vessel, after expansion with a round and straight balloon, the stent will definitely over-expand the small blood vessel at the distal end and maintain its lumen close to the proximal end. This will not only damage the distal blood vessel, but also cause a large difference in lumen diameter between the over-expanded blood vessel at the distal end of the stent and the healthy blood vessel adjacent to it, causing blood flow to stagnate here and cause dissection. If the stent is selected based on the diameter of the distal blood vessel, it is easy to cause problems such as excessive expansion and fracture of the proximal stent, and it will also cause insufficient radial support at the proximal end of the stent and fail to effectively support the blood vessel.

[0004] Although the above problems can be circumvented by directly using a conical balloon to expand the round and straight-shaped balloon-expandable stent into a conical shape to adapt to the conical blood vessel, this method not only has a great dependence on the shape of the balloon, but also faces new challenges. Since the shape of the round and straight-shaped stent after expansion mainly depends on the conical balloon, and the stent will retract to varying degrees after expansion, it is easy to cause the final shape of the stent to not match the shape of the blood vessel itself (such as taper, etc.), which makes the stent and the blood vessel poorly fit. In addition, since the blood vessel diameters corresponding to the proximal end and the distal end of the stent are different, the radial support force requirements of the stent at different positions in the length direction of the completely occluded conical blood vessel will also be different. The larger the blood vessel diameter, the greater the retraction pressure of the blood vessel on the stent, and the greater the support force required by the stent; the smaller the blood vessel diameter, the smaller the retraction pressure of the blood vessel on the stent, and the smaller the support force required by the stent. Stents with a round and straight design may experience over-expansion of the distal stent, under-expansion of the proximal stent, and edge peeling due to the uniformity of the pattern design, resulting in insufficient performance in some parts of the stent, or excessive performance in some parts. As a result, the round and straight stent cannot self-adjust to conical lesions when used in conical blood vessels, and there is still a problem of poor wall adhesion. Summary of the invention

[0005] In order to overcome the defects and shortcomings of the above-mentioned prior art, the present invention provides an adaptive ball-expandable conical stent, which can adapt itself to a cone shape matching the blood vessel in the blood vessel, has a high degree of fit with the blood vessel wall, and well meets the use requirements of the conical stent's wall adhesion.

[0006] The present application provides a spherical expansion conical stent, including a design unit and a connection unit. The design unit includes a plurality of stent rods and a plurality of wave heads. Each wave head sequentially connects two adjacent stent rods in series to form a ring structure. The connection unit is connected between the wave heads of two adjacent design units. In the direction from the proximal end to the distal end of the stent, the radial support force F of the nth design unit is n Set to be smaller than the radial support force F of the n-1th design unit n-1 , where 2≤n≤200.

[0007] In the above technical solution provided in the present application, the radial support force F of the nth design unit from the proximal end to the distal end of the stent is n The radial support force F of the n-1th design unit n-1 The ratio is [0.5-1]:1; or the radial support force F of the nth design unit n The radial support force F of the first design unit 1 The ratio is [0.42-0.69]:1 or (0.7-1]:1; where 2≤n≤200.

[0008] In the above technical solution provided in the present application, the radial support force F of the nth design unit from the proximal end to the distal end of the stent is n The radial support force F of the n-1th design unit n-1 The ratio is M n-1 , the radial support force F of the n-1th design unit n-1 and the radial support force F of the n-2th design unit n-2 The ratio is M n-2 , the M n-1 With M n-2 The difference is between [-0.25, 0.25]; and / or the M n-2 With M n-1 Satisfies the following relationship: M n-2 =aM n-1 +b, where a∈[-1, 4], b∈[-1, 1]; 3≤n≤200.

[0009] In the above technical solution provided in this application, the radial support force F of the first design unit from the proximal end to the distal end of the stent is 1 The radial support force F of the nth design unit n The difference is between [2kPa, 200kPa].

[0010] In the above technical solution provided by this application, the radial support force F of the first design unit 1 The size is 60kPa-250kPa, and the radial support force F of the nth design unit n The size is 50kPa-200kPa.

[0011] In the above technical solution provided in the present application, the total length C of the nth design unit from the proximal end to the distal end of the stent is n Than the total length C of the n-1th design unit n-1 Short, where 2≤n≤200.

[0012] In the above technical solution provided in this application, the total length C of the nth design unit from the proximal end to the distal end of the stent is n The total length C of the n-1th design unit n-1 The ratio is (0.9-1]:1; where 2≤n≤200.

[0013] In the above technical solution provided in the present application, when the stent is expanded and fits the tapered blood vessel, the length l of the nth design unit from the proximal end to the distal end of the stent is n is the length of the n-1th design unit ι n-10.5-1 times; the length l of the design unit is 0.4mm-2.0mm.

[0014] In the above technical solution provided in the present application, the cross-sectional area S of the stent rod of the nth design unit from the proximal end to the distal end of the stent is n The cross-sectional area S of the support rod of the n-1th design unit n-1 The ratio is 0.064:1-1:1; among which, 0.0040m 2 ≤S n ≤0.0625m 2 , 0.0040≤S n-1 ≤0.0625.

[0015] In the above technical solution provided by the present application, when the stent is expanded and fits the tapered blood vessel, the angle α formed by the extension lines of the two adjacent stent rods of the nth design unit from the proximal end to the distal end is n The angle α formed by the extension lines of the two adjacent support rods of the n-1th design unit n-1 The ratio is 1:1-1.67:1, and / or the angle α formed by the extension lines of two adjacent stent rods of the nth design unit from the proximal end to the distal end of the stent n The angle α formed by the extension lines of the two adjacent support rods of the first design unit 1 The ratio is 1:1-1.67:1, where 30°≤α n <50°,30°≤α n-1 <50°.

[0016] In the above technical solution provided in the present application, the wall thickness of the nth design unit from the proximal end to the distal end of the stent is less than the wall thickness of the n-1th design unit; wherein the wall thickness of each design unit is 10% or less of the radial diameter of the blood vessel lumen at the implantation location.

[0017] In the above technical solution provided in the present application, under the back pressure of the tapered blood vessel, the maximum retraction rate of the designed unit is 5%-80%; the retraction rate of the nth designed unit from the proximal end to the distal end of the stent is greater than the retraction rate of the n-1th designed unit.

[0018] In the above technical solution provided in the present application, the total length of the ball-expanded conical bracket is 38mm-300mm.

[0019] In the above technical solution provided in the present application, the taper β of the ball-expandable conical bracket is 72°-90°.

[0020] In the above technical solution provided in the present application, the degree of fit between the ball-expandable conical stent and the blood vessel is ≥85%.

[0021] In the above technical solution provided in the present application, the proximal diameter of the ball-expanded conical stent is 2.5mm-8mm, and the distal diameter of the ball-expanded conical stent is 2mm-7.5mm.

[0022] In the above technical solution provided in the present application, the matrix of the ball-expanded conical bracket includes at least one of pure iron-based, iron-based alloy, cobalt-chromium alloy, magnesium-based alloy, pure magnesium-based, pure zinc-based, zinc-based alloy and polymer-based.

[0023] In the above technical solution provided in the present application, the balloon-expandable conical stent includes at least one of a vascular stent, a biliary stent, a pancreatic stent, an esophageal stent, a tracheal stent, a urethral stent and an intestinal stent.

[0024] The present application reasonably sets the relative size of the radial support force between two adjacent design units so that the size of the radial support force at different parts of the stent and the back pressure of the external blood vessel are fully matched. Therefore, after the stent is expanded, it can be well matched with the shape of the blood vessel and the severity of the plaque, fully resisting the squeezing force of the blood vessel, ensuring the stability of the shape of the stent while perfectly fitting with the conical section of the blood vessel, having good wall adhesion, providing good support for the vascular lesion area, and there is no clear requirement for the shape of the balloon used, which is easy to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 is a schematic plan view of a spherically expanded conical stent provided in an embodiment of the present invention;

[0027] Figure 2 is a schematic diagram of a ball-expandable conical stent provided by an embodiment of the present invention after expansion in the air;

[0028] Figure 3 is a partial schematic diagram of the ball-expandable conical stent provided by an embodiment of the present invention after expansion in a blood vessel;

[0029] Figure 4 is a cross-sectional schematic diagram of a support rod provided by an embodiment of the present invention;

[0030] Figure 5 It is a schematic diagram of malapposition OCT provided by an embodiment of the present invention. Description of the drawings:

[0032] 1. bracket; 11. design unit; 111. bracket rod; 112. wave head; 12. connection unit. DETAILED DESCRIPTION

[0033] The following are only preferred embodiments of the present invention, and the protection of the present invention is not limited to the following preferred embodiments. For example, the stent is used as an example in the embodiments, but it does not mean that the technical solution of the present invention is only applicable to the stent. It should be pointed out that for those skilled in the art, several modifications and improvements made on the basis of this invention concept belong to the protection scope of the present invention. The reagents or instruments used without indicating the manufacturer are all conventional products that can be purchased commercially.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0035] Test method:

[0036] Radial support force

[0037] The radial support force of the spherically expanded conical stent 1 and each design unit 11 in the present invention is obtained by testing with a radial support force tester produced by MSI in the following manner:

[0038] After the ball-expanding conical stent 1 is expanded to its nominal diameter D' in vitro, the part of the ball-expanding conical stent 1 to be tested is placed in a radial support force tester to simulate the actual stress state of the ball-expanding conical stent 1 in the blood vessel, so that the ball-expanding conical stent 1 is compressed and deformed under the action of the pressure head, and the pressure exerted on the stent when the diameter of the ball-expanding conical stent 1 is reduced to 90% of the nominal diameter D of the ball-expanding conical stent 1 during the radial compression process is measured. Among them, "nominal diameter" refers to the diameter of the stent when the stent is fully expanded under nominal pressure, and "nominal pressure" refers to the pressure required to fully expand the stent clinically; "full expansion" refers to the state when the stent is expanded to match the diameter of the lumen to which it is applied. The radial support force of each design unit 11 can be characterized by cutting out a single design unit 11 as an independent ball-expanding conical stent 1 and using it to characterize its radial support force.

[0039] Fit

[0040] The "fit degree" mentioned in the present invention refers to the degree to which the stent rods 111 of the ball-expandable conical stent 1 fit the blood vessel wall after implantation and expansion. That is, the fit degree M is equal to the total number of stent rods 111 that fit well between the ball-expandable conical stent and the blood vessel wall after implantation. 贴合 Total number of all bracket rods 111 with ball expansion cone bracket l 总Ratio of:

[0041]

[0042] The degree of fit is determined by using intravascular imaging equipment such as OCT (optical coherence tomography) and IVUS (intravascular ultrasound) to observe the fit between each stent rod 111 of the spherical-expandable conical stent 1 and the blood vessel wall, and then determine the overall fit value of the spherical-expandable conical stent 1.

[0043] The "proximal end" and "distal end" mentioned in the embodiment of the present invention are defined as: taking the distance between the entire spherical-expandable conical stent 1 and the heart after being implanted in the living body as a reference, the end close to the heart is the proximal end, and the end away from the heart is the distal end.

[0044] like Figure 1 and Figure 2 As shown, an adaptive ball-expanding conical bracket 1 provided in an embodiment of the present invention includes a design unit 11 and a connection unit 12, wherein the design unit 11 includes a plurality of bracket rods 111 and a plurality of wave heads 112, wherein each bracket rod 111 is arranged at intervals, and each wave head 112 sequentially connects two adjacent bracket rods 111 in series to form a ring structure. Specifically, each bracket rod 111 is constructed into a corresponding shape according to the design requirements, such as two adjacent bracket rods 111 are inclined or parallel to each other, and then the two adjacent bracket rods 111 are sequentially connected in series through the wave head 112, so as to form a closed ring structure as a whole. Optionally, the design unit 11 formed by connecting each bracket rod 111 and each wave head 112 in series can be a continuous corrugated structure. In this way, with the bracket from the proximal end to the distal end as the reference direction, each wave head 112 becomes the crest and trough of the corrugated structure respectively. There are multiple design units 11, and the number of design units 11 can be selected according to the length requirement of the bracket to be formed. The two adjacent design units 11 can be opposite to each other in terms of crests and troughs, or opposite to each other in terms of crests and troughs, and the connection unit 12 is connected between the wave heads 112 of the two adjacent design units 11, that is, the connection unit 12 can be connected between crests and crests, between crests and troughs, or between troughs and troughs. The specific connection method can be selected according to the design requirements. Figure 1 Between two adjacent design units 11, the wave heads 112 facing each other are set as a group. The connection units 12 can be connected between the two opposite wave heads 112 at intervals of two or more groups. This can achieve the connection between the design units 11 and reduce the number of connection units 12 set on the entire bracket, which is beneficial to reducing the overall material usage of the bracket.

[0045] In the embodiment of the present invention, the radial support force F of the nth design unit 11 of the stent is n Set to be smaller than the radial support force F of the n-1th design unit 11n-1 , where 2≤n≤200. In this way, by reasonably setting the relative size of the radial support force between two adjacent design units 11, after the stent is expanded, the stent is subjected to different back pressures of the external blood vessels, and different parts of the stent undergo different deformations according to the pressure size, so that it can be well matched with the shape of the blood vessel and the severity of the plaque, fully resist the squeezing force of the blood vessel, ensure the stability of the shape of the stent, and perfectly fit with the tapered blood vessel, have good wall adhesion, provide good support for the vascular lesion area, and there is no clear requirement for the shape of the balloon used, which is easy to use.

[0046] The ball-expandable conical stent 1 provided in the embodiment of the present invention, by adopting the above-mentioned design, realizes that the radial support force of the stent is adjustable along the length direction, and can be expanded into a cone using a round straight balloon. The radial support force of the conical stent 1 is reduced along the axial direction of the stent, and the different plaque sizes, plaque hardness, and vascular taper in different parts of the vascular lesion area will give different sizes of back pressure to the design units 11 at the corresponding parts of the stent, so that the design units 11 at different positions of the expanded stent will retract to different degrees under the action of the corresponding back pressure, thereby forming a certain taper from the proximal end to the distal end, and the taper of the stent can be well matched with the taper of the blood vessel, thereby achieving a good wall adhesion effect.

[0047] In the embodiment of the present invention, the stent rod 111 and the wave head 112 can be made of the same material or different materials. The material can be a non-degradable material or a degradable material that meets the requirements for the use of the stent. The degradable material can be iron, iron-based alloy, magnesium, magnesium-based alloy, zinc, zinc-based alloy or absorbable polymer material, and the material of the non-degradable part can be nickel-titanium alloy, cobalt-chromium alloy or stainless steel.

[0048] The spherically expanded conical stent 1 provided by the present invention has a radial support force F of the nth design unit 11 along the direction from the proximal end to the distal end. n is the radial support force F of the n-1th design unit 11 n-1 [0.5, 1] ​​times, where 2≤n≤300. Further, the radial support force F of the nth design unit 11 from the proximal end to the distal end of the ball-expanded conical stent 1 is n is the radial support force F of the n-1th design unit 11 n-1 In some embodiments of the invention, Fn F n-1 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 0.98, 0.99, 0.999 or 0.9999 times; in some other embodiments, F n F n-1 0.52, 0.58, 0.62, 0.72, 0.78, 0.82, 0.88, 0.9, 0.92, 0.95, 0.96, 0.98 or 0.985 times. In other embodiments, F n Can be F n-1 In some other embodiments, F n Can be F n-1 In the range of any two numbers between [0.5, 1), such as F n Can be F n-1 [0.63, 0.87] times of , and so on.

[0049] In some possible embodiments of the present invention, along the direction from the proximal end to the distal end of the spherically expanded conical stent 1, the radial support force F of the nth design unit 11 is n The radial support force F of the first design unit 11 1 The ratio of can also be [0.42, 0.69]:1 or (0.7, 1]:1. Furthermore, the radial support force F of the nth design unit 11 is n The radial support force F of the first design unit 11 1 The ratio of can be a new interval range composed of any two values ​​in the interval [0.42, 0.69]:1 or (0.7, 1]:1, such as the radial support force F of the nth design unit 11 of the ball-expandable conical stent 1 from the proximal end to the distal end. n The radial support force F of the first design unit 11 1 The ratio is [0.45, 0.65]:1 or (0.7, 0.99]:1, and so on. Furthermore, the radial support force F of the nth design unit 11 from the proximal end to the distal end of the ball-expandable conical stent 1 is n The radial support force F of the first design unit 11 1 The ratio is [0.50, 0.65]:1 or (0.7, 0.95]:1.

[0050] In some embodiments provided by the present invention, the ratio of the radial support forces of every two adjacent design units 11 is equal, such as F 3 / F 2 =F 2 / F 1 =F4 / F 3 =F 5 / F 4 =F 6 / F 5 =F 8 / F 7 ......, and so on; in some other embodiments, the ratio of the radial support force of any two adjacent design units 11 is not equal, such as F 3 / F 2 ≠F 2 / F 1 ≠F 4 / F 3 ≠F 5 / F 4 ≠F 6 / F 5 ≠F 8 / F 7 ......, and so on; In some other embodiments, the radial supporting forces of some two adjacent design units 11 are equal, and the radial supporting forces of some two adjacent design units 11 are unequal, such as F 3 / F 2 ≠F 2 / F 1 ≠F 4 / F 3 , while F 5 / F 4 =F 6 / F 5 =F 8 / F 7 , or F 3 / F 2 ≠F 5 / F 4 ≠F 8 / F 7 , while F 2 / F 1 =F 4 / F 3 =F 6 / F 5 , that is, the radial supporting force of each design unit 11 in the present invention can decrease in equal proportion or in non-equal proportion.

[0051] In the embodiment of the present invention, along the direction from the proximal end to the distal end of the stent, the radial support force F of the nth design unit is n and the radial support force F of the n-1th design unit n-1 The ratio is M n-1 , the radial support force F of the n-1th design unit n-1 and the radial support force F of the n-2th design unit n-2The ratio is M n-2 , M n-1 With M n-2 The difference is between [-0.25, 0.25], and / or the M n-2 With M n-1 Between M n-2 =aM n-1 +b, where a∈[-1, 4], b∈[-1, 1], 3≤n≤200. Further, the M n-1 With M n-2 The difference is between [-0.15, 0.15], and / or the M n-2 With M n-1 Between M n-2 =aM n-1 +b, where a∈[-1, 3], b∈[-1, 1], 3≤n≤200. By adopting this design, the support performance of each design unit 11 in the spherical expansion conical stent 1 has a large adjustment space, and can be designed into different performances according to actual application needs, thereby obtaining a stent of the shape actually required, which can be well fitted with the blood vessel wall at the implantation site, avoiding the increased risk of thrombosis caused by poor stent adhesion and the problem of restenosis in the stent.

[0052] In some embodiments provided by the present invention, along the direction from the proximal end to the distal end of the spherically expanded conical stent 1, the radial support force F of the first design unit 11 is 1 The radial support force F of the nth design unit 11 n The difference is between [2 kPa, 200 kPa]. Further, the radial support force F of the first design unit 11 is 1 The radial support force F of the nth design unit 11 n The difference can be within the new interval range formed by any two values ​​in the interval [2kPa, 200kPa], such as F 1 With F n The difference is between [2kPa, 180kPa], [2kPa, 160kPa], [5kPa, 180kPa], [5kPa, 160kPa], [6kPa, 150kPa], [8kPa, 145kPa], [5kPa, 145kPa], [2kPa, 145kPa], [10kPa, 145kPa], [12kPa, 145kPa] or [15kPa, 145kPa], etc. Further, the radial support force F of the first design unit 11 1 The radial support force F of the nth design unit 11 n The difference is between [3kPa, 150kPa]; further, the radial support force F of the first design unit 111 The radial support force F of the nth design unit 11 n The difference is between [8kPa, 140kPa]; further, the radial support force F of the first design unit 11 1 The radial support force F of the nth design unit 11 n The difference is between [12kPa, 110kPa]. Radial support force F 1 With F n If the difference is too large or too small, it is easy to cause the proximal support force of the stent to be excessive or the distal support force to be insufficient, which can easily cause the stent to have too much proximal support force under the back pressure of the blood vessel, excessively constrain the blood vessel, and insufficient distal support force, resulting in excessive blood vessel rebound, so that the blood vessel cannot be well supported. At the same time, its wall adhesion performance is also easily greatly affected, and ultimately causes problems such as increased risk of intravascular thrombosis and restenosis of the stent. In the present invention, by adopting the above-mentioned setting method for the radial support force size of each design unit 11 in the stent, the use requirements of the support performance and wall adhesion performance of the stent are well met.

[0053] In the above technical solution provided by the present invention, the radial support force F of the proximal end of the ball-expandable conical stent 1 is 1 The size is 60kPa-250kPa, and the radial support force F at the distal end n The magnitude of the radial support force is 50kPa-200kPa. Further, the radial support force of the proximal end of the ball-expanding conical stent 1 is 65kPa-200kPa, and the radial support force of the distal end is 50kPa-180kPa; further, the radial support force of the proximal end of the ball-expanding conical stent 1 is 70kPa-180kPa, and the radial support force of the distal end is 55kPa-150kPa; further, the radial support force of the proximal end of the ball-expanding conical stent 1 is 75kPa-140kPa, and the radial support force of the distal end is 55kPa-130kPa.

[0054] In the embodiment of the present invention, along the direction from the proximal end to the distal end of the stent, the total length C of the nth design unit 11 is n The total length C of the n-1th design unit 11 n-1 The ratio is (0.9-1]:1; where 2≤n≤200. Specifically, it can be seen from the above that each design unit 11 is composed of a plurality of support rods 111 and a plurality of wave heads 112. Therefore, the total length of each design unit 11 refers to the sum of the lengths of all the support rods 111 and the wave heads 112 on the design unit 11. The present application sets the total length C of the nth design unit 11 n The total length C of the n-1th design unit 11 n-1, the radial supporting force can be changed by adjusting the total length of the stent rods 111 and the wave heads 112 on each design unit 11. That is, the longer the total length of the stent rods 111 and the wave heads 112 of each design unit 11, the higher the metal coverage of the design unit 11 under the same expansion diameter, and therefore the greater its ability to resist radial deformation, and the greater the radial supporting force. Moreover, the longer the total length of the stent rods 111 and the wave heads 112 of each design unit 11, the more material there is to meet the requirement for material length during expansion deformation, and thus the unit can be expanded into different shapes, adapt to blood vessels of different shapes, and improve the fit with the blood vessels. In the present invention, the length l of the design unit 11 can be adjusted by adjusting the number of stent rods of the design unit 11. n , and at least one of the size and shape of the wave head. When the total length C of the design unit 11 is achieved by adjusting the number of support rods of the design unit 11 n When the size of the stent is , the number of stent rods in the first design unit 11 from the proximal end to the distal end is less than 15% more than the number of stent rods in the n-th design unit 11; further, the number of stent rods in the first design unit 11 from the proximal end to the distal end is less than 10% more than the number of stent rods in the n-th design unit 11; further, the number of stent rods in the first design unit 11 from the proximal end to the distal end is less than 5% more than the number of stent rods in the n-th design unit 11.

[0055] In the embodiment of the present invention, when the stent is expanded to fit the tapered blood vessel, the length of the nth design unit 11 is increased from the proximal end to the distal end of the stent. n Set to the length of the n-1th design unit 11 n-1 Further, the length of the n-th design unit 11 is 0.55-1, 0.58-1, 0.6-1, 0.55-0.98, 0.6-0.95, 0.65-1 or 0.65-0.98 times the length of the n-1-th design unit 11; further, the length of the n-th design unit 11 is 0.65-0.9, 0.7-0.98 or 0.7-0.95 times the length of the n-1-th design unit 11.

[0056] In the above technical solution provided by the embodiment of the present invention, when the stent is expanded to fit the conical blood vessel, the length ι of the design unit 11 of the stent is 0.4mm-2.0mm. Further, the length ι of the design unit 11 of the stent is 0.5mm-2.0mm; further, the length l of the design unit 11 of the stent is 0.8mm-2.0mm. Figure 1 The length l of the design unit 11 mentioned above refers to the distance between two wave heads 112 in the same design unit 11 along the direction from the proximal end to the distal end of the stent.

[0057] In the above technical solution provided by the present invention, along the direction from the proximal end to the distal end of the stent, the cross-sectional area S of the stent rod 111 of the nth design unit 11 is n The cross-sectional area S of the support rod 111 of the n-1th design unit 11 n-1 The ratio is 0.064:1-1:1; among which, 0.0040m 2 ≤S n ≤0.0625m 2 , 0.0040m 2 ≤S n-1 ≤0.0625m 2 . Reference Figure 4 , the cross-sectional area of ​​the support rod 111 is obtained by multiplying the width W of the support rod at the cross section by the wall thickness H of the support rod. Since the wall thickness H of the support rod gradually decreases from the proximal end to the distal end of the support, and the width W of the support rod remains unchanged or gradually decreases, the cross-sectional area of ​​the support rod 111 also gradually decreases. Specifically, the wall thickness of the nth design unit 11 is less than the wall thickness of the n-1th design unit 11, which can be that the average wall thickness of the nth design unit 11 is less than the average wall thickness of the n-1th design unit 11; or it can be that from the proximal end to the distal end, the wall thickness of each design unit 11 gradually decreases uniformly, that is, the wall thickness of the support rod of a single design unit 11 gradually decreases uniformly; it can also be that the wall thickness of the support rod of a single design unit 11 of the support is a certain value, but the wall thickness of two adjacent design units 11 shows a decreasing trend. This arrangement can make the radial supporting force of the stent from the proximal end to the distal end tend to decrease. After the stent is implanted in the blood vessel, it will be subjected to different back pressures from the external blood vessels and will retract to varying degrees, forming a taper that matches the blood vessel well, thereby achieving good wall adhesion performance, which meets the requirements for the stent's wall adhesion performance.

[0058] like Figure 1 and Figure 4 As shown, the spherical expansion conical stent 1 provided in the embodiment of the present invention has a stent rod wall thickness H that gradually decreases from the proximal end to the distal end. In some other embodiments, the stent rod width W may gradually narrow from the proximal end to the distal end; in some embodiments, the stent rod width W of some design units 11 remains unchanged from the proximal end to the distal end, and the stent rod width W of some design units 11 gradually narrows; in some embodiments, the stent rod width W remains unchanged from the proximal end to the distal end.

[0059] like Figure 4As shown, the cross-sectional area of ​​the support rod 111 is the product of the support rod width W and the support rod wall thickness H. In one embodiment, the support rod width W in the design unit 11 at the leftmost end of the support can be 105μm, and the support rod wall thickness H can be 70μm, and the support rod width W in the design unit 11 at the rightmost end can be 92μm, and the support rod wall thickness H can be 55μm. Or in another embodiment, the support rod width W in the design unit 11 at the leftmost end of the support is 160μm, and the support rod wall thickness H is 115μm, and the support rod width W in the design unit 11 at the rightmost end is 136μm, and the support rod wall thickness H is 90μm. Or in yet another embodiment, the support rod width W in the design unit 11 at the leftmost end of the support is 160μm, and the support rod wall thickness H is 115μm, and the support rod width W in the design unit 11 at the rightmost end is 105μm, and the support rod wall thickness H is 70μm. Or in another embodiment, the width W of the support rod in the design unit 11 at the leftmost end of the support is 160 μm, and the wall thickness H of the support rod is 115 μm, and the width W of the support rod in the design unit 11 at the rightmost end is 92 μm, and the wall thickness H of the support rod is 55 μm. The choice of specific size can be selected according to the design requirements. The "support rod wall thickness" of the design unit described in the present invention refers to the average wall thickness of the support rod of the design unit, which can be a fixed determined value for the support rod wall thickness of the design unit, or a non-fixed determined value for the support rod wall thickness of the design unit, which changes gradually.

[0060] In the above technical solution provided by the present invention, the wall thickness of the stent is 10% or less of the radial diameter of the lumen of the blood vessel where it is implanted. Generally speaking, the smaller the diameter of the blood vessel, the more sensitive it is to the wall thickness H of the stent rod, because the same wall thickness of the stent rod under different blood vessel diameters, although the space occupied in the radial direction of the blood vessel lumen is the same, but the radial proportion of the lumen of blood vessels with different diameters is very different. For example, when the wall thickness H of the stent rod is 100 μm, the proportion of the wall thickness of the stent rod in the radial direction of the blood vessel diameter is 10%, 6.7% and 5% respectively. When the wall thickness of the stent in the radial direction of the blood vessel accounts for a large proportion, it will significantly affect the dynamics of local blood flow through the stent rod 111, causing blood to more easily adhere to and deposit on the stent rod 111, increasing the risk of thrombosis in the stent. Therefore, the present invention can well improve the influence of the wall thickness of the stent rod on the hemodynamics by designing the wall thickness of the stent rod. Further, the wall thickness of the stent 1 provided by the present invention is 6% or less of the radial diameter of the lumen of the blood vessel where it is implanted, such as 5%, 3%, etc.

[0061] Please refer to Figure 1 In some possible implementations, when the stent is expanded to fit the conical blood vessel, the angle α formed by the extension lines of two adjacent stent rods 111 of the nth design unit 11 is nThe angle α formed by the extension lines of two adjacent support rods 111 of the n-1th design unit 11 n-1 Further, from the proximal end to the distal end, the angle α formed by the extension lines of two adjacent support rods 111 of the nth design unit 11 is n The angle α formed by the extension lines of the two adjacent support rods 111 of the n-1th design unit 11 n-1 The ratio is [1-1.67]:1, and / or the angle α formed by the extension lines of two adjacent stent rods of the nth design unit from the proximal end to the distal end of the stent n The angle α formed by the extension lines of the two adjacent support rods of the first design unit 1 The ratio is 1:1-1.67:1, where 30°≤α n <50°,30°≤α n-1 <50°. The angle formed by the extension lines of two adjacent stent rods 111 of the stent directly affects the support force of the stent. As the angle formed by the extension lines of two adjacent stent rods 111 of the stent increases, it helps to reduce the radial support force of the stent, so that the stent can finally form a taper that matches the shape of the blood vessel well. The angle α formed by the extension lines of two adjacent stent rods 111 of the stent is also referred to as the stent opening angle.

[0062] In some possible embodiments, after the stent is expanded, under the action of the tapered blood vessel, the retraction rate B of the design unit 11 is 0%-80%; further, after the stent is expanded, under the action of the tapered blood vessel, the retraction rate B of the design unit 11 is 2%-80%; further, after the stent is expanded, under the action of the tapered blood vessel, the retraction rate B of the design unit 11 is 2%-66%; further, after the stent is expanded, under the action of the tapered blood vessel, the retraction rate B of the design unit 11 is 2%-50%; further, after the stent is expanded, under the action of the tapered blood vessel, the retraction rate B of the design unit 11 is 3%-45%. In some embodiments of the present invention, after the stent is expanded and under the action of the tapered blood vessel, the retraction rate B of the design unit 11 is 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 38%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80%; in other embodiments of the present invention, after the stent is expanded and under the action of the tapered blood vessel, the retraction rate B of the design unit 11 is 6%, 9%, 12%, 18%, 22%, 28%, 32%, 38%, 42%, 48%, 52%, 58%, 62%, 68% or 69%.

[0063] It can be understood that, according to the design requirements, the length of the stent is formed by connecting a plurality of design units 11, and the retraction rate B of each design unit 11 is between 0% and 80%. The retraction rate B of some design units 11 of the stent is 0%, which means that one or several design units 11 may not retract after expansion, and their retraction rate is 0%. The other design units 11 retract to a certain extent under the action of the tapered blood vessel, and finally the overall shape of the whole stent is still basically tapered.

[0064] In some possible implementations, under the back pressure of the tapered blood vessel, the maximum retraction rate of each design unit 11 is 5%-80%. That is, each design unit 11 of the stent has a certain retraction rate, but the maximum retraction rate of the design unit 11 of the stent is within the range of 5%-80%, that is, among the multiple design units 11 of the stent, some design units 11 have a retraction rate less than 5%, or even 0%, and the retraction rate of the largest design unit among the numerous design units 11 is between 5%-80%, that is, in some specific implementations, the maximum retraction rate of the design unit 11 of the stent may be 5%; in some specific implementations, the maximum retraction rate of the design unit 11 of the stent is 10%; in some specific implementations, the maximum retraction rate of the design unit 11 of the stent may be 15%; in some specific implementations, the maximum retraction rate of the design unit 11 of the stent may be 25%; in some specific implementations, the maximum retraction rate of the design unit 11 of the stent may be 35%; in some specific implementations, the maximum retraction rate of the design unit 11 of the stent may be 45%, and so on. The "shrinkage rate" B in the present invention = 100%*(D 2 -D 1 ) / D 2 , where: D 1 D is the diameter of the middle part of the above-mentioned design unit 11 after the design unit 11 is expanded and retracted by a certain balloon with a certain force in the blood vessel; 2 It is the diameter of the middle part of the same design unit 11 of the stent after it is expanded by the same balloon with the same force in vitro. For example, when a design unit 11 of the stent is expanded by a balloon with a force of 8 atm in a blood vessel (atm is a common unit for atmospheric pressure, and the value of 1 standard atmospheric pressure is recorded as 1 atm), after the balloon is withdrawn and the back pressure of the blood vessel wall acts on it, the final diameter D of the design unit 11 is 1 The diameter D of the design unit 11 after being expanded by the same balloon with a force of 8 atm under in vitro atmospheric pressure is 2.1 mm. 2 is 2.5 mm, then the retraction rate B of the design unit 11 n =100%*(2.5-2.1) / 2.5=16%.

[0065] The retraction rate of a certain part of the stent in the present invention depends on the diameter of the reference blood vessel at that part of the stent and the size of the supporting force of that part of the stent, as well as the relative relationship between the two. After the stent expands in the blood vessel, it is affected by the back pressure of the blood vessel. The larger the reference diameter of the blood vessel, the smaller the back pressure of the blood vessel on the stent. At the same time, if the supporting force of the stent is greater, the stent retracts less; the smaller the reference diameter of the blood vessel, the greater the back pressure of the blood vessel on the stent. At the same time, if the supporting force of the stent is smaller, the stent retracts more. If the stent does not fit the blood vessel wall adaptively, the stent rod 111 is likely to be suspended inside the blood vessel, thereby increasing the risk of thrombosis in the stent.

[0066] In the above technical solution provided by the present invention, the length of the bracket is 38mm-300mm.

[0067] The "length of the stent" mentioned in the present invention refers to the axial length of the stent when the stent is implanted in the body and expanded to the final state.

[0068] The "reference blood vessel diameter" mentioned in the present invention refers to the blood vessel diameter within 5 mm at both ends of the vascular lesion.

[0069] In the above technical solution provided by the present invention, the proximal diameter of the stent is 2.5-8 mm, and the distal diameter is 2 mm-7.5 mm.

[0070] In the above technical solution provided by the present invention, the taper β of the stent is 72°-90°. Further, the taper β of the stent is 75°-90°; further, the taper β of the stent is 80°-90°; further, the taper β of the stent is 85°-90°. The "taper" mentioned in the present invention refers to the inclination of the stent as a whole from the proximal end to the distal end in the final state after the stent is implanted in the body and retracts under the force of the blood vessel. Specifically, refer to Figure 3 , draw a straight line a perpendicular to the proximal cross section from one end of the stent proximal end 1 , and draw a line between the two endpoints of the proximal and distal ends of the stent as straight line a 2 , the straight line a 1 With straight line a 2 The included angle between them is β, which is the taper of the bracket.

[0071] In the above technical solution provided by the present invention, the stent matrix is ​​any material suitable for ball-expandable stents, including but not limited to pure iron-based, iron-based alloys, cobalt-chromium alloys, magnesium-based alloys, pure magnesium-based, pure zinc-based, zinc-based alloys and polymer-based.

[0072] The iron-based alloy is an iron-based alloy having a carbon content not higher than 2.11 wt.%.

[0073] In the above technical solution provided by the present invention, the stent is at least one of a vascular stent, a biliary stent, a pancreatic stent, an esophageal stent, a tracheal stent, a urethral stent and an intestinal stent. Further, the vascular stent includes a peripheral stent; further, the vascular stent includes a femoral artery stent and a below-the-knee stent.

[0074] In the above technical solution provided by the present invention, the degree of fit between the stent and the blood vessel is ≥85%. Further, the degree of fit between the stent and the blood vessel is ≥88%; further, the degree of fit between the stent and the blood vessel is ≥90%.

[0075] A spherical expansion tapered stent 1 provided in an embodiment of the present invention is formed by regulating at least one of the parameters such as the circumference of the stent rod 111, the cross-sectional area of ​​the stent rod 111, and the angle between two adjacent stent rods 111 in each design unit 11, so as to form a spherical expansion tapered stent 1 whose radial support force decreases along the axial direction of the stent. The spherical expansion tapered stent 1 is delivered to a lumen such as a vascular lesion area by a delivery system, and after the lesion area is expanded and depressurized by a balloon, the stent will retract to different degrees due to the different radial support forces at different parts of the stent and the different back pressures from the external blood vessels, and finally rebound to form an ideal cone, thereby matching the taper of the blood vessel well and having good wall adhesion. That is, the present invention provides a stent that can adapt to become a cone from the proximal end to the distal end under the back pressure of the blood vessel wall in the conical vascular lesion area. The balloon-expandable conical stent 1 has no clear requirements on the shape of the balloon used in the expansion process. Even in the presence of a round straight balloon, it can also adaptively form a cone with good wall adhesion according to the shape of the conical blood vessel in the lesion area. It has low requirements on the shape of the balloon needed for expansion, which greatly improves the convenience of use and operation.

[0076] In order to facilitate the understanding of the present invention, the design points of the present invention are described below in conjunction with some specific embodiments. It can be understood that the relevant embodiments are only some examples of the solutions of the present invention and do not constitute a limitation on the scope of application.

[0077] Embodiment 1

[0078] Provided is a ball-expanded conical stent 1, which is formed by 38 design units 11 connected to each other by connecting units, each design unit is formed by a plurality of stent rods 111 and a plurality of wave heads 112 connected to each other according to design requirements, and two adjacent design units 11 are connected by connecting units 12, and the connecting units are Ω-shaped. The axial length ι of each design unit 11 gradually decreases from the proximal end to the distal end, and is 1.17mm, 1.16mm, 1.15mm, 1.14mm, 1.12mm, 1.11mm, 1.10mm, 1.09mm, 1.08mm, 1.07mm, 1.06mm, 1.05mm, 1.04mm, 1.03mm, 1.02mm, 1.01mm, 1.00mm, 0.99mm, 0.98mm, 0.97mm, 0.96mm, 0.95mm, 0.94mm, 0.93mm, 0.92mm, 0.91mm, 0.90mm, 0.89mm, 0.88mm, 0.87mm, 0.87mm, 0.86mm, 0.85mm, 0.84mm, 0.83mm, 0.82mm, 0.81mm, 0.80mm. The total length C of the stent rod and the wave head of each design unit decreases in equal proportion from the proximal end to the distal end. The total length C of the first design unit 11 is 1 The total length C of the 38th design unit 11 is 22.31 mm. 38 It is 12.75mm and the common ratio is 0.985.

[0079] refer to Figure 1 , along the same axial reference direction, the angle α between two adjacent stent rods 111 in each design unit 11 increases gradually in equal proportion along the axial direction from the proximal end to the distal end. The angle α of the first design unit 11 is 1 is 31.0°, and the common ratio is 1.002. The wall thickness of the design unit at the most proximal end of the stent is 70 μm, and the wall thickness of the design unit at the most distal end is 55 μm. Figure 4 As shown, the cross-sectional area of ​​the support rod is the product of the width of the support rod and the thickness of the support wall. Figure 1 It can be seen that the cross-sectional area of ​​the stent rod decreases in equal proportion from the proximal end to the distal end along the axial direction. The cross-sectional area S of the stent rod of the first design unit 11 is 1 0.00735mm 2 , the cross-sectional area S of the support rod of the 38th design unit 11 38 0.00507mm 2 , the common ratio is 0.99.

[0080] refer to Figure 1The radial support forces of the above-designed stents from the proximal end to the distal end are 150 kPa, 148 kPa, 147 kPa, 145 kPa, 144 kPa, 142 kPa, 140 kPa, 139 kPa, 137 kPa, 136 kPa, 134 kPa, 133 kPa, 131 kPa, 130 kPa, 128 kPa, 127 kPa, 126 kPa, respectively. a, 124kPa, 123kPa, 122kPa, 120kPa, 119kPa, 118kPa, 116kPa, 115kPa, 114kPa, 113kPa, 11 1kPa, 110kPa, 109kPa, 108kPa, 106kPa, 105kPa, 104kPa, 103kPa, 102kPa, 101kPa and 100kPa.

[0081] like Figure 2 As shown, the above-mentioned stent is expanded to a nominal diameter of 4mm in the air using a round straight balloon, and the diameters of each design unit 11 at the distal and proximal ends are kept consistent, and the stent length is 40mm. It is implanted in a conical blood vessel with a proximal reference blood vessel diameter of 4mm, a distal reference blood vessel diameter of 2mm, a length of 40mm, and a blood vessel taper of 88.6°. Since the radial support force of the stent decreases along the length direction, and the decreasing trend is fully consistent with the conical structure of the blood vessel and the location and size of the plaque on the blood vessel, when the stent is implanted under the expansion force of the cylindrical balloon, the stent shrinks into a conical shape that fully fits the conical blood vessel, without over-expansion of the blood vessel or residual stenosis, and the maximum retraction rate of each design unit is 50%. The OCT test calculation shows that the degree of fit is 96%, and the stent has good wall adhesion. At the same time, the maximum proportion of the wall thickness of the vascular stent in the radial direction of the implanted blood vessel lumen is 5.5%. After the stent was implanted in the blood vessel, no thrombosis was caused. Follow-up after 1 year of implantation showed that the blood vessel was unobstructed.

[0082] Embodiment 2

[0083] Provided is a spherical expansion conical stent 1, which is composed of 40 design units 11 connected to each other by connecting units, each design unit is composed of a plurality of stent rods 111 and a plurality of wave heads 112 connected to each other according to design requirements, and two adjacent design units 11 are connected by connecting units 12, and the connecting units are S-shaped. The axial length of each design unit 11 gradually decreases from the proximal end to the distal end, and the length l of each design unit is 1.49mm, 1.48mm, 1.48mm, 1.47mm, 1.47mm, 1.46mm, 1.46mm, 1.45mm, 1.45mm, 1.44mm, 1.44mm, 1.43mm, 1.43mm, 1.42mm, 1.41mm, 1.41mm, 1.40mm, 1.4 0mm, 1.39mm, 1.39mm, 1.38mm, 1.38mm, 1.37mm, 1.37mm, 1.36mm, 1.36mm, 1.35mm, 1.35mm, 1.34mm, 1.34mm, 1.33mm, 1.33mm, 1.32mm, 1.32mm, 1.31mm, 1.31mm, 1.30mm, 1.30mm, 1.29mm, 1.29mm. The total length C of the stent rod and the wave head of each design unit decreases in equal proportion from the proximal end to the distal end. The total length C of the first design unit 11 is 1 It is 35.76mm and the common ratio is 0.993.

[0084] refer to Figure 1 , along the same axial reference direction, the angle α between two adjacent stent rods 111 in each design unit 11 increases gradually in equal proportion along the axial direction from the proximal end to the distal end. The angle α of the first design unit 11 is 1 The angle is 31.0° and the common ratio is 1.007. The wall thickness of the design unit at the most proximal end of the stent is 115 μm, and the wall thickness of the design unit at the most distal end is 90 μm. Figure 4 As shown, the cross-sectional area of ​​the support rod is the product of the width of the support rod and the thickness of the support wall. Figure 1 It can be seen that the cross-sectional area of ​​the stent rod decreases proportionally along the axial direction from the proximal end to the distal end. The cross-sectional area S of the stent rod of the first design unit 11 is 1 0.01840mm 2 , the cross-sectional area S of the support rod of the 40th design unit 11 40 0.01195mm 2 , the common ratio is 0.989.

[0085] refer to Figure 1The radial support forces of each design unit of the above-designed stent from the proximal end to the distal end are 200kPa, 198kPa, 197kPa, 195kPa, 194kPa, 192kPa, 191kPa, 189kPa, 188kPa, 186kPa, 185kPa, 183kPa, 182kPa, 181kPa, 179kPa, 178kPa, 176kPa, 175kPa, 174kPa, 172kPa, 171kPa, 170kPa, 168kPa, 167kPa, 166kPa, 164kPa, 163kPa, 162kPa, 161kPa, 159kPa, 158kPa, 157kPa, 156kPa, 154kPa, 153kPa, 152kPa, 151kPa, 150kPa, 149kPa, 147kPa.

[0086] like Figure 2 As shown, the above-mentioned stent is expanded to a nominal diameter of 8mm in the air using a round straight balloon, the diameters of each design unit 11 at the distal and proximal ends are kept consistent, and the stent length is 58mm. It is implanted in a conical blood vessel with a proximal reference blood vessel diameter of 8mm, a distal reference blood vessel diameter of 5mm, a length of 55mm, and a vascular taper of 88.4°. Since the radial support force of the stent decreases along the length direction, the stent will shrink into a conical shape that fully fits the conical blood vessel, without over-expansion of the blood vessel or residual stenosis. The maximum retraction rate is 37.5%. Calculated by OCT testing, its fit is 97%, and the stent has good wall adhesion. At the same time, the maximum proportion of the wall thickness of the vascular stent in the radial direction of the implanted blood vessel lumen is 3.6%. After the stent was implanted in the blood vessel, it did not cause thrombosis. Follow-up one year after implantation showed that the blood vessel was unobstructed.

[0087] Embodiment 3

[0088] A spherical expansion conical stent 1 is provided, which is composed of 80 design units 11 connected to each other through connecting units. Each design unit is composed of multiple stent rods 111 and multiple wave heads 112 connected to each other according to design requirements. Two adjacent design units 11 are connected by connecting units 12, and the connecting units are Ω-shaped. The axial length of each design unit 11 gradually decreases from the proximal end to the distal end. Specifically, the length of the 1st to 20th design units is l 1 -l 20 The lengths of the 21st to 40th design units are all 1.49 mm. 21 -l 40 The lengths of the 41st to 60th design units are all 1.40 mm. 41 -l 60 The lengths of the 61st to 80th design units are all 1.37 mm. 61 -l80 The total length C of the stent rod and wave head of each design unit decreases in equal proportion from the proximal end to the distal end, with a common ratio of 0.997. The total length C of the first design unit 1 It is 35.76mm.

[0089] refer to Figure 1 , along the same axial reference direction, the angle α between two adjacent stent rods 111 in each design unit 11 gradually increases along the axial direction from the proximal end to the distal end, and the angle α of the 1st to the 20th design units 11 is 1 -α 20 is 31.0°, and the angle α of the 21st to 40th design units 11 21 -α 40 is 34.7°, and the angle α of the 41st to 60th design units 11 41 -α 60 is 36.2°, and the angle α of the 61st to 80th design units 11 61 -α 80 The wall thickness of the design unit at the most proximal end of the stent is 115 μm, and the wall thickness of the design unit at the most distal end is 90 μm. Figure 4 As shown, the cross-sectional area of ​​the support rod is the product of the width of the support rod and the thickness of the support wall. Figure 1 It can be seen that the cross-sectional area of ​​the stent rod gradually decreases along the axial direction from the proximal end to the distal end. The cross-sectional area of ​​the stent rod of the 1st to 20th design unit 11 is 1 -S 20 0.01840mm 2 , the cross-sectional area S of the support rod of the 21st to 40th design unit 11 21 -S 40 0.01542mm 2 , the cross-sectional area S of the support rod of the 41st to 60th design unit 11 41 -S 60 0.01443mm 2 , the cross-sectional area S of the support rod of the 61st to 80th design unit 11 61 -S 80 0.01222mm 2 .

[0090] Reference Figure 1 The radial support force F of the stent designed above from the proximal end to the distal end of the 1st to the 20th design unit 11 is 1 -F 20 The radial support force F of the 21st to 40th design units 11 is 200 kPa. 21 -F 40 The radial support force F of the 41st to 60th design units 11 is 176 kPa.41 -F 60 The radial support force F of the 61st to 80th design unit 11 is 168 kPa. 61 -F 80 Both are 150kPa.

[0091] like Figure 2 As shown, the above-mentioned stent is expanded to a nominal diameter of 8mm in the air using a round straight balloon, and the diameters of each design unit 11 from the distal end to the proximal end are consistent, and the stent length is 120mm. It is implanted in a conical blood vessel with a proximal reference blood vessel diameter of 8mm, a distal reference blood vessel diameter of 7.5mm, a length of 120mm, and a vascular taper of 89.9°. Since the radial support force of the stent decreases along the length direction, the stent will shrink into a conical shape that fully fits the conical blood vessel, without over-expansion of the blood vessel or residual stenosis. The maximum retraction rate is 6.25%. Calculated by OCT testing, its fit is 95%, and the stent has good wall adhesion. At the same time, the maximum proportion of the wall thickness of the vascular stent in the radial direction of the implanted blood vessel lumen is 3.6%. After the stent was implanted in the blood vessel, no thrombosis was caused. Follow-up one year after implantation showed that the blood vessel was unobstructed.

[0092] Embodiment 4

[0093] A spherical expansion conical stent 1 is provided, which is composed of 200 design units 11 connected to each other through connecting units, each design unit is composed of multiple stent rods 111 and multiple wave heads 112 connected to each other according to design requirements, and two adjacent design units 11 are connected by connecting units 12, and the connecting units are S-shaped. The axial length of each design unit 11 gradually decreases from the proximal end to the distal end, specifically, the length l of the 1st to the 50th design unit 1 -l 50 All are 1.40 mm, the 51st to 100th design units l 51 -l 100 All are 1.37 mm, 101st to 150th design units l 101 -l 150 All are 1.30 mm, 151st to 200th design units l 151 -l 200 The total length of the stent rod and wave head of each design unit decreases in equal proportion from the proximal end to the distal end, with a common ratio of 0.998. The total length C of the first design unit 1 It is 35.76mm.

[0094] refer to Figure 1 , along the same axial reference direction, the angle α between two adjacent stent rods 111 in each design unit 11 gradually increases along the axial direction from the proximal end to the distal end, and the angle α of the 1st to the 50th design unit 11 is 1-α 50 is 34.7°, and the angle α of the 51st to 100th design units 11 51 -α 100 is 36.2°, and the angle α of the 101st to 150th design units 11 101 -α 150 is 40.2°, and the angle α of the 151st to 200th design units 11 151 -α 200 The wall thickness of the design unit at the most proximal end of the stent is 115 μm, and the wall thickness of the design unit at the most distal end is 70 μm. Figure 4 As shown, the cross-sectional area of ​​the support rod is the product of the width of the support rod and the thickness of the support wall. Figure 1 It can be seen that the cross-sectional area of ​​the stent rod gradually decreases along the axial direction from the proximal end to the distal end. The cross-sectional area S of the stent rod of the 1st to the 50th design unit 11 is 1 -S 50 Both are 0.01840mm 2 , the cross-sectional area S of the support rod of the 51st to 100th design unit 11 51 -S 100 0.01542mm 2 , the cross-sectional area S of the support rod of the 101st to 150th design unit 11 101 -S 150 0.01222mm 2 , the cross-sectional area S of the support rod of the 151st to 200th design unit 11 151 -S 200 0.00735mm 2 .

[0095] refer to Figure 1 The radial support force F of the stent designed above from the proximal end to the distal end of the 1st to the 50th design unit is 1 -F 50 The radial support force F of the 51st to 100th design units is 200 kPa. 51 -F 100 The radial support force F of the 101st to 150th design units is 176 kPa. 101 -F 150 The radial support force F of the 151st to 200th design units is 150 kPa. 151 -F 200 It is 140kPa.

[0096] like Figure 2As shown, the above-mentioned stent is expanded to a nominal diameter of 8mm in the air using a round straight balloon, the diameters of the distal and proximal design units 11 are consistent, and the stent length is 300mm. It is implanted in a conical blood vessel with a proximal reference blood vessel diameter of 8mm, a distal reference blood vessel diameter of 4mm, a length of 300mm, and a blood vessel taper of 89.6°. Since the radial support force of the stent decreases along the length direction, the stent will shrink into a conical shape that fully fits the conical blood vessel, without over-expansion of the blood vessel or residual stenosis. The maximum retraction rate is 50%. Calculated by OCT testing, its fit is 93%, and the stent has good wall adhesion. At the same time, the maximum proportion of the wall thickness of the vascular stent in the radial direction of the implanted blood vessel lumen is 3.5%. After the stent was implanted in the blood vessel, it did not cause thrombosis. Follow-up one year after implantation showed that the blood vessel was unobstructed.

[0097] Embodiment 5

[0098] A spherical expansion conical stent 1 is provided, which is composed of 27 design units 11 connected to each other through connecting units, each design unit is composed of multiple stent rods 111 and multiple wave heads 112 connected to each other according to design requirements, and two adjacent design units 11 are connected by connecting units 12, and the connecting units are S-shaped. The axial length of each design unit 11 gradually decreases from the proximal end to the distal end, specifically, the length l of the first to the ninth design units 11 is 1 -l 9 are 1.49 mm, and the length l of the 10th to 18th design units 11 10 -l 18 is 1.30 mm, and the length l of the 19th to 27th design units 11 19 -l 27 The total length C of the support rod 111 and the wave head 112 in each design unit 11 decreases in equal proportion from the proximal end to the distal end, with a common ratio of 0.987. The total length C of the first design unit 11 is 1 =35.76 mm. Along the same axial reference direction, the angle α between two adjacent support rods 111 in each design unit 11 gradually increases from the proximal end to the distal end. Specifically, the angle α of the 1st to the 9th design unit 11 is 1 -α 9 The angles α of the 10th to 18th design units 11 are all 31.0°. 10 -α 18 The angles α of the 19th to 27th design units 11 are all 34.7°. 19 -α 27 The values ​​are all 36.2°. Figure 4 As shown, the cross-sectional area of ​​the support rod is the product of the width of the support rod and the thickness of the support wall. Figure 1It can be seen that the cross-sectional area of ​​the stent rod gradually decreases along the axial direction from the proximal end to the distal end. Specifically, the cross-sectional area S of the stent rod 111 in the first to ninth design units 11 is 1 -S 9 0.01840mm 2 , the cross-sectional area S of the support rod 111 in the 10th to 18th design units 11 10 -S 18 0.01222mm 2 , the cross-sectional area S of the support rod 111 in the 19th to 27th design units 11 19 -S 27 0.00735mm 2 .

[0099] refer to Figure 1 The radial support force F of the stent designed above from the proximal end to the distal end, the 1st to the 9th design unit 11 1 -F 9 The radial support force F of the 10th to 18th design unit 11 is 200 kPa. 10 -F 18 The radial support force F of the 19th to 27th design units 11 is 150 kPa. 19 -F 27 It is 100kPa.

[0100] like Figure 2 As shown, the above-mentioned stent is expanded to a nominal diameter of 8mm in the air using a round straight balloon, the diameter of the design unit 11 at the distal and proximal ends of the stent is kept consistent, and the stent length is 40mm. It is implanted in a conical blood vessel with a proximal reference blood vessel diameter of 8mm, a distal reference blood vessel diameter of 2mm, a length of 40mm, and a blood vessel taper of 85.7°. Since the radial support force of the stent decreases along the length direction, and the decreasing trend is fully consistent with the conical structure of the blood vessel and the location and size of the plaque on the blood vessel, the stent shrinks into a cone that fully fits the conical blood vessel, without excessive expansion of the blood vessel or residual stenosis. The maximum retraction rate in each design unit 11 is 75%. The degree of fit is 88% calculated by OCT test, and the stent rod has good wall adhesion. At the same time, the maximum proportion of the wall thickness of the vascular stent in the radial direction of the implanted blood vessel lumen is 5.5%. After the stent was implanted in the blood vessel, no thrombosis was caused. Follow-up after 1 year of implantation showed that the blood vessel was unobstructed.

[0101] Embodiment 6

[0102] Provided is a spherical expansion conical stent 1, which is composed of 38 design units 11 connected to each other by connecting units, each design unit is composed of a plurality of stent rods 111 and a plurality of wave heads 112 connected to each other according to design requirements, and two adjacent design units 11 are connected by connecting units 12, and the connecting units are Ω-shaped. The axial length l of each design unit 11 gradually decreases from the proximal end to the distal end, and is 1.17mm, 1.16mm, 1.15mm, 1.14mm, 1.12mm, 1.11mm, 1.10mm, 1.09mm, 1.08mm, 1.07mm, 1.06mm, 1.05mm, 1.04mm, 1.03mm, 1.02mm, 1.01mm, 1.00mm, 0.99mm, 0.98mm, 0.97mm, 0.96mm, 0.95mm, 0.94mm, 0.93mm, 0.92mm, 0.91mm, 0.90mm, 0.89mm, 0.88mm, 0.87mm, 0.87mm, 0.86mm, 0.85mm, 0.84mm, 0.83mm, 0.82mm, 0.81mm, 0.80mm. The total length C of the stent rod and the wave head of each design unit decreases proportionally from the proximal end to the distal end, and C 1 is 22.31 mm, and the total length C of the 5th to 10th design units 11 5 -C 10 The first one is reduced by a proportional value of 0.905, and the rest are reduced by a proportional value of 0.985.

[0103] refer to Figure 1 , along the same axial reference direction, the angle α between two adjacent stent rods 111 in each design unit 11 gradually increases in equal proportion along the axial direction from the proximal end to the distal end, α 1 is 31.0°, and the angle α of the 1st to 11th design units 11 1 -α 11 The angle α of the 12th to 36th design units 11 increases according to the proportional value 1.002. 12 -α 36 The angle α of the 37th design unit 11 is increased by a proportional value of 1.01. 37 The angle α of the 38th design unit 11 is increased by a proportional value of 1.45. 38 The wall thickness of the design unit at the most proximal end of the stent is 70 μm, and the wall thickness of the design unit at the most distal end is 55 μm. Figure 4 As shown, the cross-sectional area of ​​the support rod is the product of the width of the support rod and the thickness of the support wall. Figure 1 It can be seen that the cross-sectional area of ​​the stent rod decreases in equal proportion along the axial direction from the proximal end to the distal end. The cross-sectional area S 1 0.00735mm 2 , S 380.00507mm 2 , the common ratio is 0.99.

[0104] refer to Figure 1 , the supporting forces of each design unit of the above-designed stent from proximal to distal end are 150kPa, 148kPa, 147kPa, 144kPa, 141kPa, 138kPa, 134kPa, 131kPa, 128kPa, 125kPa, 128kPa, 126kPa, 125kPa, 124kPa, 123kPa, 122kPa, 121kPa, 120kPa, 119kPa, 118kPa, 116kPa, 115kPa, 114kPa, 112kPa, 110kPa, 109kPa, 108kPa, 107kPa, 106kPa, 105kPa, 104kPa, 102kPa, 101kPa, 99kPa, 98kPa, 97kPa, 90kPa and 88kPa respectively.

[0105] like Figure 2 As shown, the above-mentioned stent is expanded to a nominal diameter of 4mm in the air using a round straight balloon, and the diameters of each design unit 11 at the distal and proximal ends are kept consistent, and the stent length is 40mm. It is implanted in a conical blood vessel with a proximal reference blood vessel diameter of 4mm, a distal reference blood vessel diameter of 2mm, a length of 40mm, and a blood vessel taper of 88.6°. Since the radial support force of the stent decreases along the length direction, and the decreasing trend is fully consistent with the conical structure of the blood vessel and the location and size of the plaque on the blood vessel, when the stent is implanted under the expansion force of the cylindrical balloon, the stent shrinks into a conical shape that fully fits the conical blood vessel, without over-expansion of the blood vessel or residual stenosis. The maximum retraction rate of each design unit is 50%, and the degree of fit is 93% calculated by OCT test, and the stent has good wall adhesion. At the same time, the maximum proportion of the wall thickness of the vascular stent in the radial direction of the implanted blood vessel lumen is 5.5%. After the stent was implanted in the blood vessel, no thrombosis was caused. Follow-up after 1 year of implantation showed that the blood vessel was unobstructed.

[0106] Embodiment 7

[0107] Provided is a spherical expansion conical stent 1, which is composed of 38 design units 11 connected to each other by connecting units, each design unit is composed of a plurality of stent rods 111 and a plurality of wave heads 112 connected to each other according to design requirements, and two adjacent design units 11 are connected by connecting units 12, and the connecting units are Ω-shaped. The axial length l of each design unit 11 gradually decreases from the proximal end to the distal end, and is 1.17mm, 1.16mm, 1.15mm, 1.14mm, 1.12mm, 1.11mm, 1.10mm, 1.09mm, 1.08mm, 1.07mm, 1.06mm, 1.05mm, 1.04mm, 1.03mm, 1.02mm, 1.01mm, 1.00mm, 0.99mm, 0.98mm, 0.97mm, 0.96mm, 0.95mm, 0.94mm, 0.93mm, 0.92mm, 0.91mm, 0.90mm, 0.89mm, 0.88mm, 0.87mm, 0.87mm, 0.86mm, 0.85mm, 0.84mm, 0.83mm, 0.82mm, 0.81mm, 0.80mm. The total length C of the stent rod and the wave head of each design unit decreases proportionally from the proximal end to the distal end. The total length C of the first design unit 11 is 1 is 22.31 mm, and the total length C of the 5th to 10th design units 11 5 -C 10 The first one is reduced by a proportional value of 0.905, and the rest are reduced by a proportional value of 0.985.

[0108] refer to Figure 1 , along the same axial reference direction, the angle α between two adjacent stent rods 111 in each design unit 11 increases gradually in equal proportion along the axial direction from the proximal end to the distal end. The angle α of the first design unit 11 is 1 is 31.0°, and the angle α of the 1st to 11th design units 11 1 -α 11 The angle α of the 12th to 36th design units 11 increases according to the proportional value 1.002. 11 -α 36 The angle α of the 37th design unit 11 is increased by a proportional value of 1.01. 37 The angle α of the 38th design unit 11 increases by a proportional value of 1.1. 38 The wall thickness of the design unit at the most proximal end of the stent is 70 μm, and the wall thickness of the design unit at the most distal end is 55 μm. Figure 4 As shown, the cross-sectional area of ​​the support rod is the product of the width of the support rod and the thickness of the support wall. Figure 1 It can be seen that the cross-sectional area of ​​the stent rod decreases in equal proportion along the axial direction from the proximal end to the distal end. The cross-sectional area S 1 0.00735mm2 , S 38 0.00507mm 2 , the common ratio is 0.99.

[0109] refer to Figure 1 , the supporting forces of each design unit of the above-designed stent from proximal to distal end are 150kPa, 148kPa, 147kPa, 144kPa, 141kPa, 138kPa, 134kPa, 131kPa, 128kPa, 125kPa, 128kPa, 126kPa, 125kPa, 124kPa, 123kPa, 122kPa, 121kPa, 120kPa, 119kPa, 118kPa, 116kPa, 115kPa, 114kPa, 112kPa, 110kPa, 109kPa, 108kPa, 107kPa, 106kPa, 105kPa, 104kPa, 102kPa, 101kPa, 99kPa, 98kPa, 97kPa, 96kPa and 95kPa respectively.

[0110] like Figure 2 As shown, the above-mentioned stent is expanded to a nominal diameter of 4mm in the air using a round straight balloon, and the diameters of each design unit 11 at the distal and proximal ends are kept consistent, and the stent length is 40mm. It is implanted in a conical blood vessel with a proximal reference blood vessel diameter of 4mm, a distal reference blood vessel diameter of 2mm, a length of 40mm, and a blood vessel taper of 88.6°. Since the radial support force of the stent decreases along the length direction, and the decreasing trend is fully consistent with the conical structure of the blood vessel and the location and size of the plaque on the blood vessel, when the stent is implanted under the expansion force of the cylindrical balloon, the stent shrinks into a conical shape that fully fits the conical blood vessel, without over-expansion of the blood vessel or residual stenosis. The maximum retraction rate of each design unit is 50%. The OCT test calculation shows that the degree of fit is 99.5%, and the stent has good wall adhesion. At the same time, the maximum proportion of the wall thickness of the vascular stent in the radial direction of the implanted blood vessel lumen is 5.5%. After the stent is implanted in the blood vessel, it does not cause thrombosis. Follow-up after 1 year of implantation shows that the blood vessel is unobstructed.

[0111] In order to further illustrate the technical effect of the spherically expanded conical stent 1 proposed by the present invention, five comparative examples are now described as examples.

[0112] Comparative Example 1

[0113] The total number of design units of the stent is 38, the length of each design unit is 1.17 mm, the total length of the stent rod and wave head in each design unit is 22.31 mm, the angle between two adjacent stent rods is 31°, the width of the stent rod is 105 μm, the wall thickness is 100 μm, and the cross-sectional area of ​​the obtained stent rod is 0.0105 mm 2 , the radial support force of the stent is 150kPa.

[0114] The above-obtained stent is expanded in the air using a round straight balloon to a nominal diameter of 4mm, with the same diameter at the proximal and distal ends, and a stent length of 48mm. It is implanted in a conical blood vessel with a proximal reference vessel diameter of 4mm, a distal reference vessel diameter of 2mm, a length of 48mm, and a vessel taper of 88.8°. Since the radial support force of the stent remains unchanged in the linear direction, the distal end of the blood vessel is over-expanded due to excessive support force, resulting in severe tearing, and the stent does not retract. Thrombus quickly crawls onto the distal stent, and restenosis and occlusion occur in the stent. Calculated by OCT testing, the degree of fit is 97%. At the same time, the maximum proportion of the wall thickness of the vascular stent in the radial direction of the implanted blood vessel lumen is 10%, which will not excessively stimulate the blood vessel to cause thrombosis.

[0115] Comparative Example 2

[0116] The total number of design units of the stent is 38, the length of each design unit is 1.17 mm, the total length of the stent rod and wave head in each design unit is 22.31 mm, the angle between two adjacent stent rods is 31°, the width of the stent rod is 105 μm, the wall thickness is 100 μm, and the cross-sectional area of ​​the obtained stent rod is 0.0105 mm 2 , the radial support force of the stent is 150kPa.

[0117] The above-obtained stent was expanded in the air using a round straight balloon to a nominal diameter of 4mm, with the same diameter at the proximal and distal ends and a stent length of 48mm. It was implanted in a conical blood vessel with a proximal reference blood vessel diameter of 5mm, a distal reference blood vessel diameter of 3mm, a length of 48mm, and a blood vessel taper of 88.8°. Since the radial support force of the stent remained unchanged in the linear direction, the distal end of the blood vessel was over-expanded due to excessive support force, resulting in severe tearing. The maximum retraction rate in each design unit was 5%. Thrombus quickly covered the distal stent, and restenosis and occlusion occurred in the stent. The proximal end of the blood vessel could not fully fit the blood vessel wall due to insufficient stent expansion. According to OCT test calculations, its fit was only 70%, which also led to the rapid climbing of thrombus on the suspended stent rod at the proximal end of the stent, and restenosis and occlusion occurred in the stent. At the same time, the maximum proportion of the wall thickness of the vascular stent in the radial direction of the implanted blood vessel lumen was 6.6%, which was less than 10%, and would not excessively stimulate the blood vessel to cause thrombosis.

[0118] Comparative Example 3

[0119] The total number of design units of the stent is 38, the length of each design unit is 1.17 mm, the total length of the stent rod and wave head in each design unit is 22.31 mm, the angle between two adjacent stent rods is 31°, the width of the stent rod is 105 μm, the wall thickness is 100 μm, and the cross-sectional area of ​​the obtained stent rod is 0.0105 mm 2 , the radial support force of the stent is 150kPa.

[0120] The stent obtained above was expanded in the air using a round straight balloon to a nominal diameter of 4mm, with the proximal and distal diameters being consistent and the stent length being 48mm. It was implanted in a conical blood vessel with a proximal reference blood vessel diameter of 8mm, a distal reference blood vessel diameter of 4mm, a length of 48mm, and a blood vessel taper of 87.6°. Since the radial support force of the stent remained unchanged along the linear direction, the distal support force of the blood vessel was appropriate, the stent was fully expanded, the stent and the blood vessel were well fitted, and the stent did not retract. Figure 5 Due to insufficient expansion of the stent at the proximal end of the blood vessel, the stent cannot fully fit the blood vessel wall. According to OCT test calculation, its fit is only 30%, which also leads to the rapid crawling of thrombus on the suspended stent rod at the proximal end of the stent, and restenosis and occlusion in the stent. At the same time, the maximum proportion of the wall thickness of the vascular stent in the radial direction of the implanted blood vessel lumen is 5%, which is less than 10%, and will not over-stimulate the blood vessel and cause thrombosis.

[0121] Comparative Example 4

[0122] The stent has a total of 38 design units, each of which is 1.17 mm long. The total length of the stent rod and wave head in each design unit is 22.31 mm. The angle between two adjacent stent rods is 31°. The stent rod width is 105 μm, the wall thickness is 100 μm, and the resulting stent rod cross-sectional area is 0.0105 mm2. The radial support force of the stent is 150 kPa, the nominal diameter is 4 mm, and the stent length is 48 mm.

[0123] After the round straight stent obtained above is implanted into a conical blood vessel (the proximal reference blood vessel diameter is 8mm, the distal reference blood vessel diameter is 4mm, the length is 48mm, and the blood vessel taper is 87.6°), a conical balloon with a proximal diameter of 8mm and a distal diameter of 4mm is used to expand it into a conical structure. The distal support force of the blood vessel is appropriate, the stent is fully expanded, the stent fits the blood vessel well, and the stent does not retract. At the proximal end, since the total length of the stent rod and wave head of each design unit of the stent is 22.31mm, which is less than the circumference of the blood vessel with a blood vessel diameter of 8mm (25.12mm), the stent cannot fit the blood vessel. Therefore, the proximal stent of the blood vessel is in a suspended state, and the proximal end of the stent has poor fit with the blood vessel. According to OCT test calculation, its fit is only 60%. At the same time, the maximum proportion of the wall thickness of the vascular stent in the radial direction of the implanted blood vessel lumen is 5.5%. After the stent is implanted in the blood vessel, thrombosis is caused due to poor fit, resulting in restenosis in the stent.

[0124] Comparative Example 5

[0125] A spherical expansion conical stent 1 is provided, which is composed of 80 design units 11 connected to each other through connecting units, each design unit is composed of multiple stent rods 111 and multiple wave heads 112 connected to each other according to design requirements, and two adjacent design units 11 are connected by connecting units 12, and the connecting units are S-shaped. The axial length of each design unit 11 gradually decreases from the proximal end to the distal end, and the length of the 1st to the 20th design unit is l 1 -l 20 is 1.49 mm, and the length l of the 21st to 40th design units 21 -l 40 The length of the 41st to 60th design unit is 1.30mm. 41 -l 60 is 1.17 mm, and the length l of the 61st to 80th design units 61 -l 80 The total length C of the stent rod and wave head of each design unit gradually decreases along the axial direction from the proximal end to the distal end. The total length C of the 1st to 20th design units is 1 -C 20 The total length C of the 21st to 40th design units is 35.76 mm. 21 -C 40 The total length C of the 41st to 60th design units is 28.61 mm. 41 -C 60 The total length C of the 61st to 80th design units is 22.89 mm. 61 -C 80 It is 18.31mm.

[0126] refer to Figure 1, along the same axial reference direction, the angle α between two adjacent stent rods 111 in each design unit 11 increases gradually in equal proportion from the proximal end to the distal end along the axial direction, and the angle α of the 1st to the 20th design unit 11 is 1 -α 20 is 20.0°, and the angle α of the 21st to 40th design units 21 -α 40 is 35.0°, and the angle α of the 41st to 60th design units 41 -α 60 is 50.0°, and the angle α between the 61st to the 80th design unit 61 -α 80 The wall thickness of the design unit at the most proximal end of the stent is 115 μm, and the wall thickness of the design unit at the most distal end is 50 μm. Figure 4 As shown, the cross-sectional area of ​​the support rod is the product of the width of the support rod and the thickness of the support wall. Figure 1 It can be seen that the cross-sectional area of ​​the stent rod gradually decreases from the proximal end to the distal end along the axial direction. The cross-sectional area S of the stent rod of the 1st to 20th design unit 11 is 1 -S 20 0.01840mm 2 , the cross-sectional area S of the support rod of the 21st to 40th design unit 11 21 -S 40 0.01222mm 2 , the cross-sectional area S of the support rod of the 41st to 60th design unit 11 41 -S 60 0.00735mm 2 , the cross-sectional area S of the support rod of the 61st to 80th design unit 11 61 -S 80 0.00425mm 2 .

[0127] refer to Figure 1 , the radial support force F of the stent designed above from the 1st to the 20th design unit from the proximal end to the distal end 1 -F 20 The radial support force F of the 21st to 40th design units is 230 kPa. 21 -F 40 The radial support force F of the 41st to 60th design units is 180 kPa. 41 -F 60 The radial support force F of the 61st to 80th design units is 150 kPa. 61 -F 80 It is 80kPa.

[0128] like Figure 2As shown, the above-mentioned stent is expanded to a nominal diameter of 8mm in the air using a round straight balloon, and the diameter of the proximal and distal stents is the same, and the stent length is 120mm. It is implanted in a conical blood vessel with a proximal reference blood vessel diameter of 8mm, a distal reference blood vessel diameter of 2mm, a length of 120mm, and a vascular taper of 88.6°. Since the radial support force of the stent decreases along the length direction, the stent will shrink into a conical shape that fully fits the conical blood vessel, without over-expansion of the blood vessel or residual stenosis. However, since the total length of the design unit is reduced in a step-like manner, and the reduction ratio is too large, the support force in the intermediate transition area is too different, resulting in the stent not being able to fit the blood vessel well and retract, and the maximum retraction rate is only 50%. According to OCT test calculation, its fit is only 60%. At the same time, the wall thickness of the vascular stent accounts for a maximum of 5.5% in the radial direction of the implanted blood vessel lumen. After the stent is implanted in the blood vessel, thrombosis occurs due to poor fit, resulting in restenosis in the stent.

[0129] In summary, an embodiment of the present invention provides a ball-expandable conical stent, the radial supporting force of which gradually decreases along the axial direction of the stent. By utilizing the differences in plaque size, plaque hardness, and vascular taper at different parts of the vascular lesion area, different sizes of back pressures are applied to the design units and stent rods of the corresponding parts of the stent, so that the design units or stent rods at different positions of the expanded stent will retract to different degrees under the action of the corresponding back pressures, thereby forming a certain taper from the proximal end to the distal end. The taper of the stent can be well matched with the taper of the blood vessel, thereby achieving a good wall-adherence effect.

[0130] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A spherical expansion conical stent, comprising a design unit and a connection unit, wherein the design unit comprises a plurality of stent rods and a plurality of wave heads, each of the stent rods being arranged at intervals, and each of the wave heads sequentially connects two adjacent stent rods in series to form a ring structure; the design unit is provided with a plurality of units, and the connection unit is connected between the wave heads of two adjacent design units, characterized in that: The radial support force F of the nth design unit from the proximal end to the distal end of the stent n Less than the radial support force F of the n-1th design unit n-1 , where 2≤n≤200.

2. The spherically expanded conical stent according to claim 1, characterized in that: The radial support force F of the nth design unit from the proximal end to the distal end of the stent n The radial support force F of the n-1th design unit n-1 The ratio is [0.5-1]:1; or the radial support force F of the nth design unit n The ratio of the radial support force F1 to the first design unit is [0.42-0.69]:1 or (0.7-1]:1; wherein 2≤n≤200.

3. The spherically expanded conical stent according to claim 1, characterized in that: The radial support force F of the nth design unit from the proximal end to the distal end of the stent n The radial support force F of the n-1th design unit n-1 The ratio is M n-1 , the radial support force F of the n-1th design unit n-1 and the radial support force F of the n-2th design unit n-2 The ratio is M n-2 , the M n-1 With M n-2 The difference is between [-0.25, 0.25]; and / or the M n-2 With M n-1 Satisfies the following relationship: M n-2 =aM n-1 +b, where a∈[-1, 4], b∈[-1, 1]; 3≤n≤200.

4. The spherically expanded conical stent according to claim 1, characterized in that: The radial support force F1 of the first design unit from the proximal end to the distal end of the stent is equal to the radial support force F n The difference is between [2kPa, 200kPa].

5. The spherically expanded conical stent according to claim 1, characterized in that: The radial support force F1 of the first design unit is 60kPa-250kPa, and the radial support force F n The size is 50kPa-200kPa.

6. The spherically expanded conical stent according to claim 1, characterized in that: The total length C of the nth design unit of the stent from the proximal end to the distal end n Than the total length C of the n-1th design unit n-1 Short, where 2≤n≤200.

7. The spherically expandable conical stent according to claim 1, characterized in that: The total length C of the nth design unit from the proximal end to the distal end of the stent n The total length C of the n-1th design unit n-1 The ratio is (0.9-1]:1; where 2≤n≤200.

8. The spherically expanded conical stent according to claim 1, characterized in that: When the stent is expanded and fits the conical blood vessel, the length l of the nth design unit from the proximal end to the distal end of the stent is n is the length l of the n-1th design unit n-1 0.5-1 times of the length l of the design unit is 0.4-2.0mm.

9. The spherically expandable conical stent according to claim 1, characterized in that: The cross-sectional area S of the stent rod of the nth design unit from the proximal end to the distal end of the stent n The cross-sectional area S of the support rod of the n-1th design unit n-1 The ratio is 0.064:1-1:1; among which, 0.0040m 2 ≤S n ≤0.0625m 2 , 0.0040≤S n-1 ≤0.0625.

10. The spherically expandable conical stent according to claim 1, characterized in that: When the stent is expanded and fits the conical blood vessel, the angle α formed by the extension lines of the two adjacent stent rods of the nth design unit from the proximal end to the distal end of the stent is n The angle α formed by the extension lines of the two adjacent support rods of the n-1th design unit n-1 The ratio is 1:1-1.67:1, and / or the angle α formed by the extension lines of two adjacent stent rods of the nth design unit from the proximal end to the distal end of the stent n The ratio of the angle α1 formed by the extension lines of the two adjacent support rods of the first design unit is 1:1-1.67:1, wherein 30°≤α n <50°,30°≤α n-1 <50°.

11. The spherically expandable conical stent according to claim 1, characterized in that: The wall thickness of the nth design unit from the proximal end to the distal end of the stent is less than the wall thickness of the n-1th design unit; wherein the wall thickness of each design unit is 10% or less of the radial diameter of the lumen of the blood vessel where it is implanted.

12. The spherically expandable conical stent according to any one of claims 1 to 11, characterized in that: Under the back pressure of the tapered blood vessel, the maximum retraction rate of the designed unit is 5%-80%; the retraction rate of the nth designed unit from the proximal end to the distal end of the stent is greater than the retraction rate of the n-1th designed unit.

13. The spherically expandable conical stent according to any one of claims 1 to 11, characterized in that: The total length of the ball-expanded conical stent is 38mm-300mm.

14. The spherically expandable conical stent according to any one of claims 1 to 11, characterized in that: The taper β of the ball-expanded conical bracket is 72°-90°.

15. The spherically expandable conical stent according to any one of claims 1 to 11, characterized in that: The degree of fit between the ball-expandable conical stent and the blood vessel is ≥85%.

16. The spherically expandable conical stent according to any one of claims 1 to 11, characterized in that: The proximal diameter of the ball-expanded conical stent is 2.5mm-8mm, and the distal diameter of the ball-expanded conical stent is 2mm-7.5mm.

17. The spherically expandable conical stent according to any one of claims 1 to 11, characterized in that: The matrix of the ball-expanded conical bracket includes at least one of pure iron-based, iron-based alloy, cobalt-chromium alloy, magnesium-based alloy, pure magnesium-based, pure zinc-based, zinc-based alloy and polymer-based.

18. The spherically expandable conical stent according to any one of claims 1 to 11, characterized in that: The balloon-expandable conical stent includes at least one of a vascular stent, a biliary stent, a pancreatic stent, an esophageal stent, a tracheal stent, a urethral stent and an intestinal stent.

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