CN114652486A

CN114652486A - Covered stent

Info

Publication number: CN114652486A
Application number: CN202011532816.0A
Authority: CN
Inventors: 肖本好; 方毅
Original assignee: Shenzhen Xianjian Changtong Medical Co ltd
Current assignee: Lifetech Scientific Shenzhen Co Ltd
Priority date: 2020-12-23
Filing date: 2020-12-23
Publication date: 2022-06-24

Abstract

The invention relates to a covered stent, which comprises a bent tube body, wherein the central axis of the bent tube body is an arc line section, so that a large bent side and a small bent side which are opposite are formed, and the bending angle theta of the arc line section is more than 0 degree and less than or equal to 180 degrees; the bending pipe body comprises at least one first main body wave ring, the first main body wave ring comprises a plurality of main body wave bars which are connected end to end, and the main body wave bars face to the small bending side of the bending pipe body to be bent. After the covered stent is implanted into a body, the bending angle theta of the covered stent can be well matched with the bending degree of the large bending side and the small bending side of a diseased blood vessel, and large bending deformation is not required to be generated. Therefore, the fracture caused by over-tension or compression can be effectively eliminated, and the covered stent meets the requirement of curved vessel reconstruction. Meanwhile, the phenomena of stenosis and occlusion caused by excessive bending of the covered stent can be effectively avoided.

Description

Covered stent

Technical Field

The invention relates to the technical field of medical instruments, in particular to a covered stent.

Background

In the field of interventional medicine, a delivery system is generally adopted to implant a stent graft to a target blood vessel position, and the stent graft is released and expanded to reconstruct a blood vessel passage or block a dissection, so that diseases such as hemangioma, arterial stenosis or dissection are treated. For a traditional covered stent, when the traditional covered stent is released into a bent blood vessel, the covered stent conforms to the shape of the blood vessel to generate bending deformation, and a covered fold is formed at the bending part of the covered stent to cause occlusion so as to form new stenosis and influence the blood flow rate; or the covered stent is damaged or even the metal wire is broken due to larger deformation, and the defects can finally result in poor treatment effect or even failure.

Fig. 8 shows the lesion of the Stanford B aortic dissection, specifically, the aortic arch 30 includes the ascending aorta 31, the aortic arch 32 and the descending aorta 33, and these three parts form an angle α in spatial structure. An aneurysm lesion is generated in the arch portion 32, a laceration 35 and a dissection 34 are formed, and the dissection 34 is progressed from one branch vessel of the aortic arch portion 32 to the descending aorta 33. For this kind of Stanford B aortic dissection 34 treatment, an alternative interventional treatment is, for example, implantation of a stent graft into the aortic arch to close off the lacerations and thereby reestablish the blood flow path in the aortic arch 32.

Referring to FIGS. 8, 9 and 10, if the central axis of the stent graft 20 before use is straight, i.e., the stent graft 20 is in the shape of a straight cylinder or a cone, the stent graft 20 includes a frame made of metal and a stent graft covering the frame. When implanted into the diseased vessel to close the laceration 35, the stent graft 20 is forced to bend and deform to adapt to the curved shape of the vessel in view of the flexibility of the stent graft 20, and in a popular way, the straight stent graft 20 will form a curved stent graft 20. Thus, at least the following disadvantages exist: one is that the struts of the stent graft near the side 36 of the vessel curve will have severe tensile deformation, and the struts will risk breaking due to overstretching. The wave rod 21, the wave rod 22, the wave rod 23 and the like near the blood vessel minor bend side 37 have bulges with different degrees due to compression, and the bulges generate periodic pulsation due to the change of hemodynamics, so that the wave rod with the bulges generates fatigue fracture. Thirdly, the stent graft 20 may generate a membrane fold at the small curve side, resulting in stenosis or even occlusion, which may lead to poor therapeutic effect.

Disclosure of Invention

The invention solves the technical problem of how to prevent the tectorial membrane scaffold from generating tectorial membrane folds when adapting to a bent blood vessel so as to cause occlusion or fracture.

The invention provides a film-coated support, which comprises a bent pipe body, wherein the central axis of the bent pipe body is an arc line section, so that a large bent side and a small bent side which are opposite are formed, and the value range of the bending angle theta of the arc line section is more than 0 degree and less than or equal to 180 degrees; the bending pipe body comprises at least one first main body wave ring, the first main body wave ring comprises a plurality of main body wave bars which are connected end to end, and the main body wave bars face to the small bending side of the bending pipe body to be bent.

In one embodiment, the wave height of the main wave rod gradually decreases in the direction from the large bending side to the small bending side.

In an embodiment, the main wave bars in the first main wave ring include a third main wave bar near the large bending side and a second main wave bar between the first main wave bar and the third main wave bar, the first main wave bar near the small bending side and the third main wave bar are adjacently disposed, a peak is formed at an intersection of a proximal end of the first main wave bar and a proximal end of the second main wave bar, a trough is formed at an intersection of a distal end of the second main wave bar and a distal end of the third main wave bar, the first wave bar and the third wave bar have equal bending angles, and a value range of the bending angle is 0 ° to 90 °.

In an embodiment, the first main body wave bars of two adjacent first main body wave rings have different bending angles, and the bending angle of the first main body wave bar near the middle of the bending pipe body is the largest.

In one embodiment, the stent graft is formed in a split manner and comprises a first part and a second part, wherein the first part and the second part are both of curved sheet structures, the first part is positioned on the small bending side, and the second part is positioned on the large bending side.

In one embodiment, the first portion and the second portion have equal central angles about the central axis of the stent graft in the same cross-section perpendicular to the central axis of the stent graft.

In one embodiment, the curved pipe body includes a coating film, and a thickness of a portion of the coating film on a large curve side of the curved pipe body is larger than a thickness of a portion of the coating film on a small curve side of the curved pipe body.

In one embodiment, the first portion and the second portion are spliced to form the stent graft, and a splice mark is formed at the splice, the splice mark being located between the major bend side and the minor bend side.

In an embodiment, the stent graft further includes a distal tube disposed at a distal end of the curved tube, the distal tube has a straight tubular structure, the distal tube includes a second main body wave ring, and the number of the second main body wave ring is greater than that of the first main body wave ring.

In one embodiment, the distal tube has a coating thickness less than a coating thickness of the curved tube.

One technical effect of one embodiment of the invention is that: because the covered stent comprises the bent tube body, before the covered stent is implanted into a body, the central axis of the bent tube body is an arc line segment with a bending angle theta, namely the whole bent tube body has a certain bending angle theta before being implanted into the body, and the bending angle theta can be well adapted to the bending deformation of a diseased blood vessel. After the covered stent is implanted into a body, the bending angle theta of the covered stent can be well matched with the bending degree of the large bending side and the small bending side of a diseased blood vessel, and large bending deformation is not required to be generated. Therefore, the fracture caused by over-tension or compression can be effectively eliminated, and the covered stent meets the requirement of curved vessel reconstruction. Meanwhile, the phenomena of stenosis and occlusion caused by excessive bending of the covered stent can be effectively avoided.

Drawings

FIG. 1 is a schematic structural view of a stent graft according to a first embodiment of the present invention;

FIG. 2 is a partial schematic structural view of the stent graft of FIG. 1;

FIG. 3 is a partial structural schematic view of the stent graft shown in FIG. 1;

FIG. 4 is a partial schematic structural view of the stent graft of FIG. 1;

FIG. 5 is a fourth example partial schematic structural view of the stent graft of FIG. 1;

FIG. 6 is a schematic structural view of a stent graft provided in accordance with a second embodiment of the present invention;

FIG. 7 is a schematic structural view of a stent graft provided in accordance with a third embodiment of the present invention;

FIG. 8 is a schematic view of an aortic arch lesion;

FIG. 9 is a schematic view of a prior art stent graft structure;

FIG. 10 is a schematic view of the stent graft of FIG. 9 after implantation in a curved vessel.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "inner", "outer", "left", "right" and the like as used herein are for illustrative purposes only and do not represent the only embodiments.

To more clearly describe the structure of the present invention, the terms "proximal" and "distal" are defined herein as terms commonly used in the medical device art. Specifically, in the field of medical devices, one end where blood flows in is defined as the "proximal end" and one end where blood flows out is defined as the "distal end", i.e., after the stent graft is implanted, blood flows from the proximal end to the distal end of the stent graft. When the blood vessel or the stent graft is curved, the side with a large radius of curvature is defined as a large curve side, and the side with a small radius of curvature is defined as a small curve side.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

Referring to fig. 1, the stent graft 10 provided by the invention comprises a curved tube 100, wherein the central axis of the curved tube 100 is an arc segment 43, and the curvature of the arc segment 43 can adapt to and match the curved shape of a blood vessel. The bent pipe body 100 has a bending angle, which can be represented by a bending angle θ of the arc line segment 43, the bending angle θ of the arc line segment 43 can be a value of a central angle corresponding to the arc line segment 43, and a value range of θ is more than 0 ° and less than or equal to 180 °, for example, the specific value of θ can be 30 °, 45 °, 90 °, or 180 °. In the bent pipe body 100, the bending angle θ of the arc line segment 43 is a set angle.

The stent graft 10 provided by the invention comprises a bent tube body 100, wherein the whole bent tube body 100 has a certain bending angle theta before being implanted into a body, and the bending angle theta can well adapt to the bending deformation of a diseased blood vessel. After the stent graft 10 is implanted into the body, the bending angle theta of the stent graft 10 can be well matched with the bending degree of the large bending side and the small bending side of the diseased blood vessel, and large bending deformation is not forced to be generated. Thereby effectively eliminating the fracture caused by over-tension or compression and leading the covered stent 10 to meet the requirement of the reconstruction of the bent blood vessel. Meanwhile, the stenosis and occlusion phenomena of the covered stent 10 caused by over-bending can be effectively avoided, so that the covered stent 10 is ensured to maintain normal hemodynamics, and the aim of improving the treatment effect is finally achieved.

First embodiment

Referring to fig. 1, the stent graft 10 is a tubular structure with openings at both ends, and specifically includes a curved tube 100, a distal tube 200, and a proximal tube 300. The proximal tube 300 and the distal tube 200 are connected to the proximal end and the distal end of the bending tube 100, respectively, and the central axes of the proximal tube 300 and the distal tube 200 are straight line segments. The central axis of the curved tube 100 is an arc segment 43, and the curvature of the arc segment 43 can be adapted and matched with the curved shape of the blood vessel. The bent pipe 100 has a bending angle represented by the bending angle θ of the arc segment 43, the bending angle θ of the arc segment 43 can be the central angle corresponding to the arc segment 43, and the value range can be 0 ° < θ ≦ 180 °,

the curved tubular body 100 includes at least one first body coil 110 and a coating 120. The coating 120 has a tubular shape, and the first body wave ring 110 is provided on the surface of the coating 120. When the number of the coating 120 is one layer, the first body wave ring 110 may be disposed on the inner surface of the coating 120 or on the outer surface of the coating 120. When the number of the cover films 120 is two layers, the first body wave ring 110 may be sandwiched between the two cover films 120. The first main wave ring 110 includes a plurality of main wave bars 111, the plurality of main wave bars 111 are connected end to end in sequence, a peak or a trough is formed at the intersection of the ends of two adjacent main wave bars 111, the extending direction of the arc segment 43 is taken as a reference direction, and the distance between two adjacent peaks and troughs in the reference direction is a wave height, which is obviously the length D occupied by the main wave bars 111 in the extending direction of the arc segment 43. In the invention, for adjacent wave crests and wave troughs on the same wave ring, the wave crests are closer to the proximal end of the covered stent than the wave troughs.

The curved tube 100 may be a planar-symmetric spatial pattern, and the plane of symmetry 40 of the curved tube 100 intersects the surface of the curved tube 100 to form a small bend line (i.e., the small bend line is located on the small bend side 41 of the stent graft) and a large bend line (i.e., the large bend line is located on the large bend side 42 of the stent graft), the large bend line having a radius of curvature greater than the small bend line. In the direction extending from the large bending side 42 to the small bending side 41 along the circumferential direction of the bending pipe body 100, the length D occupied by the main wave rod 111 on the same first main wave ring 110 in the extending direction of the arc segment 43 gradually decreases, i.e., the wave height gradually decreases. It will be appreciated that in other embodiments, of the plurality of first body wave turns of the curved pipe body, there may be an equality of wave heights of the body wave bars of at least one of the first body wave turns.

Referring to fig. 2, the length occupied by the main wave rod 111 closest to the major bend side 42 in the extending direction of the arc segment 43 is the largest and is denoted as H, and the length occupied by the main wave rod 111 closest to the minor bend side 41 in the extending direction of the arc segment 43 is the smallest and is denoted as H, wherein H is one to three times H. Referring to fig. 3, in addition, for a plurality of main wave bars 111 in the same first main wave ring 110, the main wave bars 111 extend from the large bend side 42 to the small bend side 41 along the circumferential direction of the bending pipe body 100, the length of the main wave bars 111 themselves gradually decreases, and the main wave bars 111 are all bent toward the small bend side. Therefore, the bent pipe body 100 can be effectively secured in a bent state by the above arrangement.

Referring to fig. 4, for three main wave rods 111 adjacently disposed in the same first main wave ring 110, the three main wave rods 111 can be referred to as a first main wave rod 111a, a second main wave rod 111b and a third main wave rod 111c, and the second main wave rod 111b is connected between the first main wave rod 111a and the third main wave rod 111 c. The first body waveguide rod 111a is closer to the minor bend 41, and the third body waveguide rod 111c is closer to the major bend 42. The intersection of the ends of the first body wave bar 111a and the second body wave bar 111b forms a peak 101, the intersection of the ends of the second body wave bar 111b and the third body wave bar 111c forms a valley 102, and the peak 101 is closer to the proximal end of the bending tube 100 and the slightly bent side 41 relative to the valley 102, so that the first body wave bar 111a, the second body wave bar 111b and the third body wave bar 111c are substantially connected to form an upright capital letter N. The bending angles formed when the first body wave rod 111a and the third body wave rod 111c are bent toward the small bend side are equal and are both defined as a bend angle β, which may be a central angle corresponding to both the first body wave rod 111a and the third body wave rod 111c, and a value of the bend angle β ranges from 0 ° to 90 °. The bending angles β of two adjacent first body wave rings 110 are equal, but may not be equal. Preferably, the bending angles of the first main wave bars of two adjacent first main wave rings are different, and the bending angles of the first main wave bars of the plurality of first main wave rings on the bending pipe body are gradually reduced from the middle to two ends, that is, the bending angle of the first main wave bar of the first main wave ring at the middle part of the bending pipe body is the largest, so that the ideal bending angle of the bending pipe body can be realized by using less first main wave rings, that is, the actual bending angle is more suitable for the blood vessel of the human body.

Referring to fig. 5, any two adjacent main body wave bars 111 in the first main body wave ring 110 are connected to each other to form a hook 130 (i.e., a wave crest or a wave trough), and the hook 130 is substantially V-shaped or inverted V-shaped. For two adjacent first main body wave rings 110, the hook 130 on one first main body wave ring 110 is referred to as a first hook 131, the hook 130 on the other first main body wave ring 110 is referred to as a second hook 132, and the first hook 131 passes through a space surrounded by the second hook 132 and is directly hooked on the second hook 132. Of course, the first hook 131 and the second hook 132 may not directly form a hanging relationship, for example, a chain ring may simultaneously pass through the space surrounded by the first hook 131 and the second hook 132, so that the first hook 131 and the second hook 132 form an indirect hanging relationship through the chain ring. Through the above-mentioned relation of establishing of hanging, can through adjusting clearance and the supporting power between first hook 131 and the second hook 132, popular saying, adjust the elasticity of establishing of hanging between first hook 131 and the second hook 132 promptly, can further optimize the compliance of whole crooked support 100, improve the ability that crooked support 100 adapts to vascular bending angle alpha (refer to and draw in figure 3). For ease of understanding, only one connection between adjacent first body wave rings is shown in FIG. 5, and other wave rings on the stent graft (e.g., wave rings on the proximal and distal tubes) may be connected in a similar inter-hanging manner, so FIG. 5 simplifies the first body wave rings and does not show the difference in wave height, i.e., the bending angle, of the body wave bars.

Referring again to fig. 1, the distal tube 200 includes a second main body wave ring 210, a distal wave ring 220, and a cover film (not numbered), the second main body wave ring 210 and the distal wave ring 220 being disposed on an inner surface and/or an outer surface of the cover film. Second body wave ring 210 is disposed near the proximal end of distal tube 200, i.e., relatively near first body wave ring 110, and distal wave ring 220 is disposed near the distal end of distal tube 200, the number of second body wave rings 210 may be greater than the number of distal wave rings 220. The second main wave ring 210 comprises a plurality of first distal wave bars 211 connected end to end in sequence, the distal wave ring 220 comprises a plurality of second distal wave bars 221 connected end to end in sequence, the cross-sectional dimension of the first distal wave bars 211 is equal to the cross-sectional dimension of the main wave bars 111, and the cross-sectional dimension of the first distal wave bars 211 is larger than the cross-sectional dimension of the second distal wave bars 221, which can be understood as the wire diameters of the various wave bars, i.e. both the first distal wave bars 211 and the main wave bars 111 are thicker than the second distal wave bars 221, in view of the fact that the various wave bars are generally elongated cylindrical (i.e. filamentous). The number of the second main body wave rings 210 is 1.5 times to 2 times that of the first main body wave rings 110, i.e. the number of the second main body wave rings 210 is larger than that of the first main body wave rings 110, so that the whole covered stent 10 can easily cross the curved blood vessel.

In the axial direction of distal tube 200, the length B occupied by first distal wave bar 211 is greater than the length B occupied by second distal wave bar 221. referring to the above description of bending tube 100, it can be understood that the wave height of second main body wave ring 210 is greater than the wave height of distal wave ring 220. Meanwhile, the maximum distance a between two adjacent first distal wave bars 211 is greater than the maximum distance a between two adjacent second distal wave bars 221, in other words, the waveform of the second main body wave ring 210 is sparser than that of the distal wave ring 220, which is beneficial to improving the sealing capability of the end of the distal tube body 200.

Any two adjacent first far-end wave bars 211 of the second main body wave ring 210 are connected with each other to form hooks, and referring to the connection relationship between the first hooks 131 and the second hooks 132, the hooks of the second main body wave ring 210 pass through the space surrounded by the hooks 130 of the first main body wave ring 110 to form a direct mutual hanging relationship. Meanwhile, for two adjacent second main body wave rings 210, the hook of one second main body wave ring 210 passes through the space surrounded by the hook of the other second main body wave ring 210 to form a direct mutual hanging relationship.

Referring to fig. 1, the proximal tube 300 includes a proximal wave ring 310 and a coating (not numbered), the proximal wave ring 310 being disposed on an inner surface and/or an outer surface of the coating. The proximal wave ring 310 comprises a plurality of proximal wave bars 311 connected end to end, and the length D occupied by the proximal wave bars 311 in the axial direction of the proximal tube 300 is smaller than the length D occupied by the main wave bars 111 in the extending direction of the arc segments 43, and it can also be understood that the wave height of the proximal wave ring 310 is smaller than that of the first main wave ring 110. The cross-sectional dimension of the proximal wave bar 311 is smaller than the cross-sectional dimension of the main wave bar 111, and the cross-sectional dimensions are understood to be the diameters of the various wave bars, that is, the main wave bar 111 is thicker than the proximal wave bar 311, in view of the fact that the various wave bars are generally elongated cylindrical (i.e., filamentous). Meanwhile, the maximum distance between two adjacent main wave bars 111 is greater than the maximum distance between two adjacent proximal wave bars 311. In other words, the wave shape of the first body wave ring 110 is sparser than the wave shape of the proximal wave ring 310, which is advantageous for improving the sealing ability of the end of the proximal tube 300.

It will be appreciated that in other embodiments, the proximal tube may further comprise a third body wave ring, and that the third body wave ring may be similar in structure to the second body wave ring at the distal tube.

It will be appreciated that in this embodiment, the proximal and distal tubes are straight tubular structures except for the intermediate curved tube, and therefore the length of the wave rod occupied in the axial direction of the tubes is used when describing the height of the wave ring of the proximal and distal tubes.

The covering films on the proximal tube 300, the bending tube 100 and the distal tube 200 may be integrally formed, and the same type of wave ring may be integrally formed, for example, for a particular first body wave ring 110, the first body wave ring 110 may be integrally formed, or different types of wave rings may be integrally formed, so that the stent graft 10 of the first embodiment may be understood as an integrally formed structure.

Second embodiment

Referring to FIG. 6, the stent graft 10 of the second embodiment is substantially the same as the stent graft 10 of the first embodiment, except that: the covered stent is a split molding structure, namely the covered stent 10 is formed by splicing two parts.

The symmetry plane of the entire stent graft 10 coincides with the symmetry plane 40 of the curved tube 100, and the central axis 44 of the stent graft 10 is formed by connecting the arc segments 43 of the curved tube 100, the straight segments of the proximal tube 300 and the distal tube 200. The symmetry plane 40 intersects the surface of the stent graft 10 to form a large curved intersection line 421 and a small curved intersection line 411, and obviously, the large curved intersection line 421 can be divided into three parts, and one part of the large curved intersection line 421 is located on the proximal tube body 300; another portion of the large curve line 421 is located on the curved tube 100, and the portion located on the curved tube 100 is actually the large curve side 42, i.e. the large curve side 42 is located on the large curve line 421; the remainder of large curve line 421 is located on distal tube 200. Similarly, minor bend 411 may be divided into three portions, with a portion of minor bend 411 being located on proximal tube 300; the other part of minor bend line 411 is located on curved tube 100, and the part located on curved tube 100 is actually minor bend 41, i.e. minor bend 41 is located on minor bend line 411; the remainder of minor bend line 411 is located on distal tube body 200. Since the radius of curvature of large curve side 42 is greater than the radius of curvature of small curve side 41, the radius of curvature of large curve line 421 is also greater than the radius of curvature of small curve line 411.

The stent graft 10 is cut with a particular cut curve 50 to enable the stent graft 10 to be divided into a first section 410 and a second section 420. Wherein, the first part and the second part are both curved surface sheet structures. The curved cut surface preferably cuts the stent graft 10 into two sections including a major curved side and a minor curved side, respectively. For example, the cut curve 50 can be understood as a curve that is perpendicular to the plane of symmetry 40 of the stent graft 10, and the central axis 44 of the stent graft 10 lies on the cut curve 50. Obviously, the portions of the cut curved surface 50 for cutting the proximal tube 300 and the distal tube 200 are both plane portions, and the portions of the cut curved surface 50 for cutting the bent tube 100 are curved portions, so that the normals to the curved portions 43 are all located within the symmetry plane 40 in view of the central axis (the arc segments 43) of the bent tube 100 being located on the curved portions. After being cut by the cutting curved surface 50, the minor curved intersecting line 411 is located on the first portion 410, and the first portion 410 is symmetrically arranged relative to the minor curved side 41; the large curved intersection line 421 is located on the second portion 420; preferably, the first portion 410 and the second portion 420 have equal central angles about the central axis 44 of the stent graft 10 in the same cross-section taken perpendicular to the central axis of the stent graft, i.e., the central angles are 180 degrees. The first portion 410 and the second tube are spliced together, and it is obvious that the first portion 410 includes one of the proximal tube 300, the bending tube 100 and the distal tube 200, and the second portion 420 includes the other of the proximal tube 300, the bending tube 100 and the distal tube 200.

It will be appreciated that in other embodiments, the central angles of the first and second portions about the central axis of the stent graft may not be equal on the same cross-section perpendicular to the central axis of the stent graft.

When the first portion 410 and the second portion 420 are spliced together, taking the first main body wave ring 110 and the coating film 120 in the bending pipe body 100 as an example for explanation, for a specific first main body wave ring 110, the first main body wave ring 110 is divided into two half wave rings, the two half wave rings are respectively positioned on the first portion 410 and the second portion 420, and when the first portion 410 and the second portion 420 are spliced together, the ends of the two half wave rings are spliced together. The film 120 of the bent pipe body 100 includes a first film 121 and a second film 122. In the same cross section, both the first film 121 and the second film 122 have a central angle of 180 ° around the central axis (arc segment 43) of the bent pipe body 100. The first cover film 121 is positioned on the first portion 410, the second cover film 122 is positioned on the second portion 420, and both sides of the first cover film 121 and the second cover film 122 are spliced with each other. For the splice between the wave ring and the coating film in the proximal tube 300 and the distal tube 200, reference may be made to the bending tube 100 described above. The same parts of the second embodiment as those of the first embodiment can refer to the related descriptions of the first embodiment, and are not repeated herein.

In this embodiment, the half-wave ring located in the middle portion (i.e. the position of the bent tube body) still adopts the design that the wave rod in the first embodiment bends toward the small bending side, and the wave height decreases from the large bending side to the small bending side, which is not described herein again.

The first portion 410 and the second portion 420 form the stent graft after being spliced, and a splice mark exists at the spliced position and is positioned between the large bending side and the small bending side. On one hand, the splicing trace can be used as a reference, the covered stent 10 is conveniently positioned during loading, the position of the covered stent 10 after release is accurate, and the small bent side 41 of the covered stent 10 after release is ensured to correspond to the small bent side of the blood vessel, namely the first part 410 is close to the small bent side of the blood vessel, and the second part 420 is close to the large bent side of the blood vessel. On the other hand, the convenience of manufacturing the stent graft 10 is improved, under the condition that the small bending side 41 and the large bending side 42 are not parallel, the processing efficiency and the precision of the stent graft 10 are facilitated by splicing, and the stent graft 10 can adapt to blood vessels with different bending degrees by selecting two parts with different bending angles or wave heights.

Third embodiment

Referring to FIG. 7, the stent graft 10 of the third embodiment is substantially the same as the second embodiment except that: the first coating film 121 and the second coating film 122 have different thicknesses at portions of the bent pipe body.

Specifically, the thickness of the second cover 122 is greater than the thickness of the first cover 121, and the bending resistance of the stent graft 10 can be improved by increasing the thickness of the second cover 122. In the processing process, a coating with a uniform thickness may be firstly disposed on the entire stent graft 10, the thickness of the coating may be determined by the number of layers of the coating, and then the number of layers of the coating is increased on the portion of the bent tube 100 located on the second portion 420, so as to increase the thickness of the second coating 122. The third embodiment is the same as the second embodiment, and reference may be made to the related description of the second embodiment, which is not repeated herein.

It can be understood that, in this embodiment, the proximal tube and the distal tube are both coated with uniform coatings, and the thicknesses of the coatings on the curved tubes are different. In other embodiments, the thickness of the coating on the curved tubular body portion of the first coating may be the same as the thickness of the coating on the proximal tubular body and the distal tubular body portion, or may be thicker than the thickness of the coating on the proximal tubular body and the distal tubular body portion, but thinner than the thickness of the coating on the curved tubular body portion of the second coating.

It can be understood that, on the basis of the stent graft of the first embodiment, the embodiment may be adopted in which the thickness of the stent graft on the side of the bent tube with the large bend is greater than the thickness of the stent graft on the side of the bent tube with the small bend.

It is understood that the stent graft provided by the present invention is only an example of the treatment of aortic arch diseases, and the stent graft of the present invention can also be used for other blood vessels, such as the abdominal aorta and the renal arteries, and the iliac arteries of the lower extremities.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A covered stent is characterized by comprising a bent tube body, wherein the central axis of the bent tube body is an arc line section, so that a large bent side and a small bent side which are opposite are formed, and the bending angle theta of the arc line section is more than 0 degree and less than or equal to 180 degrees; the bending pipe body comprises at least one first main body wave ring, the first main body wave ring comprises a plurality of main body wave bars which are connected end to end, and the main body wave bars face to the small bending side of the bending pipe body to be bent.

2. The stent graft as recited in claim 1, wherein the wave height of the bulk wave bars decreases gradually in the direction from the major camber side to the minor camber side.

3. The stent graft as recited in claim 2, wherein the main body wave bars in the first main body wave ring include a first main body wave bar adjacent to the minor curve side, a third main body wave bar adjacent to the major curve side, and a second main body wave bar between the first main body wave bar and the third main body wave bar, wherein a peak is formed at an intersection of a proximal end of the first main body wave bar and a proximal end of the second main body wave bar, a valley is formed at an intersection of a distal end of the second main body wave bar and a distal end of the third main body wave bar, and wherein the first wave bar and the third wave bar have equal bend angles, and the bend angles range from 0 ° to 90 °.

4. The stent graft of claim 3, wherein the first body struts of two adjacent first body coils have unequal bend angles, and wherein the bend angle of the first body struts near the middle of the curved tubular body is the largest.

5. The stent graft of claim 2, wherein the stent graft is formed in one piece and comprises a first portion and a second portion, the first portion and the second portion each having a curved sheet-like configuration, the first portion being located on the lesser curvature side and the second portion being located on the greater curvature side.

6. The stent graft of claim 5, wherein, in a same cross section perpendicular to the central axis of the stent graft, the first portion and the second portion have equal central angles about the central axis of the stent graft.

7. The stent graft as recited in claim 1, wherein the curved tube comprises a graft, and a thickness of a portion of the graft on a strongly curved side of the curved tube is greater than a thickness of a portion of the graft on a weakly curved side of the curved tube.

8. The stent graft of claim 5, wherein the first portion and the second portion are spliced to form the stent graft and a splice mark is formed at the splice, the splice mark being located between the major bend side and the minor bend side.

9. A stent graft as claimed in any one of claims 1 to 8, wherein the stent graft further comprises a distal tube disposed distally of the curved tube, and the distal tube is of a straight tubular configuration, the distal tube including a greater number of second main body coils than the first main body coils.

10. The stent graft of claim 9, wherein the thickness of the coating of the distal tube is less than the thickness of the coating of the curved tube.