Stent graft

Abstract

The present invention relates to a covered stent, which comprises a first stent, a second stent and a covering film. The covering film is wrapped around the first stent to form a lumen structure with a groove in the middle. The second stent is at least partially received in the groove, and the longitudinal central axis of the first stent and the longitudinal central axis of the second stent are parallel or substantially parallel. This covered stent can avoid or slow down the bottom surface of the groove from fitting the opening of the branch blood vessel.

Description

Technical Field

[0001] The present invention relates to the field of interventional medical devices, and particularly to a covered stent. Background Art

[0002] The information provided in this part is only background information related to the present disclosure, and it is not necessarily prior art.

[0003] Aneurysms and aortic dissections are common vascular diseases in clinical practice. Without medical intervention, aneurysms have the risk of rupture, posing a great threat to the patient's life.

[0004] With the continuous development of modern medical technology, a minimally invasive surgical procedure of implanting a covered stent into the body to treat aneurysms and aortic dissections has been used. Due to its small trauma and quick recovery, it has been widely applied. In this treatment method, the covered stent is compressed into a delivery device and guided into the human body along a pre-implanted guide wire track. After reaching the lesion site, the covered stent is released to isolate the lesion and reconstruct the blood flow channel. After the aneurysm and aortic dissection lose blood supply, the residual blood in the aneurysm cavity gradually forms thrombus and muscle into vascular tissue, and the dilated aneurysm wall contracts due to compression and gradually returns to a state close to the original state, thereby achieving the purpose of treating aneurysms and aortic dissections.

[0005] When the occurrence site of an aneurysm or aortic dissection is close to a branch vessel, after implanting a covered stent, the opening of the branch vessel may be blocked, resulting in blocked blood flow in the branch vessel. One of the methods in the prior art to solve this problem is to provide a groove structure on the covered stent. After implantation, the groove structure corresponds to the branch vessel, and a window is opened on the groove structure to allow blood flow through and ensure blood supply to the branch vessel. However, after the existing covered stent with a groove structure is implanted into the blood vessel, the artery at the branch site will squeeze the groove structure, resulting in a decrease in the volume of the groove structure. The covering film at the groove structure (i.e., the bottom surface of the groove) fits the opening of the branch vessel, resulting in blocked blood flow in the branch vessel, thus failing to play the role that the groove structure should play. Or, due to the squeezing effect, the distance between the window on the groove structure and the opening of the branch vessel is too close, which is not conducive to subsequent operations for reconstructing the blood supply of the branch vessel, such as the operation of guiding a guide wire into the window when establishing a delivery track, and the operation of introducing a subsequent branch stent delivery device into the window opening, etc. Summary of the Invention

[0006] Based on this, it is necessary to provide a covered stent that can avoid or slow down the fitting of the bottom surface of the groove to the opening of the branch vessel.

[0007] A covered stent includes a first stent, a second stent, and a covering film. The covering film is wrapped around the first stent to form a lumen structure with a groove in the middle. The second stent is at least partially received in the groove, and the longitudinal central axes of the first stent and the second stent are parallel or substantially parallel.

[0008] In one embodiment, the first stent includes a plurality of first corrugations and at least one second corrugation. The plurality of first corrugations are located at both ends of the first stent, and the second corrugation is located in the middle of the first stent, and the second corrugation is radially opposite to the groove.

[0009] In one embodiment, the second corrugation is a closed-loop structure with peaks and valleys or an open-loop structure with peaks and valleys.

[0010] In one embodiment, when the second corrugation is a closed-loop structure with peaks and valleys, the second corrugation includes a first non-closed corrugation and a first closed part. The first non-closed corrugation is an open-loop corrugation with peaks and valleys, and the open-loop corrugation has two free ends. The first closed part includes a straight rod, and both ends of the straight rod are directly or indirectly connected to the two free ends.

[0011] When the second corrugation is an open-loop structure with peaks and valleys, the second corrugation is an open-loop corrugation with peaks and valleys, and the open-loop corrugation has two free ends, and the two free ends are blunt structures.

[0012] In one embodiment, the second stent includes at least one third corrugation, and the third corrugation is a closed-loop structure with peaks and valleys or an open-loop structure with peaks and valleys.

[0013] In one embodiment, there are a plurality of the third corrugations, and the plurality of third corrugations are arranged at intervals along the axis or are not arranged at intervals along the axis.

[0014] In one embodiment, when the third corrugation is a closed-loop structure with peaks and valleys, the third corrugation includes a second non-closed corrugation and a second closed part. The second non-closed corrugation is an open-loop corrugation with peaks and valleys, and the open-loop corrugation has two free ends. The second closed part includes a straight connecting rod, and both ends of the straight connecting rod are directly or indirectly connected to the two free ends.

[0015] When the third corrugation is an open-loop structure with peaks and valleys, the third corrugation is an open-loop corrugation with peaks and valleys, and the open-loop corrugation has two free ends, and the two free ends are blunt structures.

[0016] In one embodiment, the groove includes a bottom surface and a side surface surrounding the bottom surface. The third corrugation is at least partially received in the groove, and the third corrugation is not fixedly connected to the bottom surface.

[0017] In one embodiment, the second stent is an integral stent formed by braiding braided wires or an integral stent formed by cutting.

[0018] In one embodiment, a first window is provided on one side of the second stent.

[0019] In one embodiment, the groove includes a bottom surface and a side surface surrounding the bottom surface. A first window is provided on a side of the second stent close to the bottom surface. The second stent is further provided with a second window, and the first window and the second window are opposite in the radial direction.

[0020] In one embodiment, the groove includes a bottom surface and a side surface surrounding the bottom surface, and at least one of the bottom surface and the side surface is provided with a through hole.

[0021] In one embodiment, the radial support strength of the first stent is P1, and the radial support strength of the second stent is P2. P1 and P2 satisfy: 1 / 2 < (P2 / P1) < 1; or, P1 and P2 satisfy: 1 ≤ (P2 / P1) ≤ 2.

[0022] At least a part of the second stent of the above-mentioned covered stent is received in the groove. When the covered stent bends along with the curvature of the blood vessel, due to the radial extrusion of the second stent, the tendency of the bottom surface of the groove to approach the branch blood vessel is blocked or restricted, so that the bottom surface of the groove can be prevented or slowed down from fitting the opening of the branch blood vessel. Description of the Drawings

[0023] Figure 1 Structural schematic diagram of a covered stent according to an embodiment;

[0024] Figure 2 For Figure 1 Isometric test view of the covered stent shown;

[0025] Figure 3 Side view of a second corrugation according to an embodiment;

[0026] Figure 4 Front view of a second corrugation according to another embodiment;

[0027] Figure 5 For Figure 4 Side view of the second corrugation shown;

[0028] Figure 6 For Figure 4 Top view of the second corrugation shown;

[0029] Figure 7 Front view of the second wave ring of another embodiment;

[0030] Figure 8 is Figure 7 Side view of the second wave ring shown;

[0031] Figure 9 is Figure 7 Top view of the second wave ring shown;

[0032] Figure 10 Front view of the third wave ring of one embodiment;

[0033] Figure 11 is Figure 10 Top view of the third wave ring shown;

[0034] Figure 12 is Figure 10 Side view of the third wave ring shown;

[0035] Figure 13 Front view of the third wave ring of another embodiment;

[0036] Figure 14 Side view of the covered stent of one embodiment;

[0037] Figure 15 Schematic structural diagram of the second stent of one embodiment;

[0038] Figure 16 Schematic structural diagram of the second stent of another embodiment;

[0039] Figure 17 Schematic structural diagram of the covered stent of another embodiment;

[0040] Figure 18 Bottom view of the third wave ring of one embodiment;

[0041] Figure 19 Bottom view of the third wave ring of one embodiment;

[0042] Figure 20 Isometric test view of the covered stent of another embodiment;

[0043] Figure 21 Isometric test view of the covered stent of another embodiment;

[0044] Figure 22 Isometric test view of the covered stent of another embodiment;

[0045] Figure 23 is Figure 1 Schematic diagram of the state of the covered stent implanted in a blood vessel shown;

[0046] Figure 24 For Figure 23 The schematic diagram of the state in which the branch stent is implanted is shown. DETAILED DESCRIPTION

[0047] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific implementation disclosed below.

[0048] 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 of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0049] In this article, "proximal" is defined as the end close to the heart, and "distal" is defined as the end away from the heart. "Axial" refers to the direction parallel to the line connecting the distal center and the proximal center of the medical device, and "radial" refers to the direction perpendicular to the above axial direction.

[0050] See also Figure 1 The stent graft 100 of one embodiment includes a first stent 110, a second stent 120 and a graft 130, wherein the graft 130 is coated on the first stent 110 to form a tubular structure with openings at both ends and a groove 140 in the middle, such as Figure 2 As shown. The tubular cavity structure has an inner cavity connected to two open ends for blood flow. The groove 140 has a bottom surface 140a and a side surface surrounding the bottom surface 140a. In one embodiment, the side surfaces are side surface 140b, side surface 140c, side surface 140d and side surface 140e. Among them, side surface 140b and side surface 140e are opposite in the axial direction, and side surface 140c and side surface 140d are opposite in the radial direction. In a state without force, the bottom surface 140a is a plane or a curved surface, and the curved surface can be a concave surface that is concave relative to the opening of the groove 140, a convex surface that is convex relative to the opening of the groove 140, or a curved surface having both a concave portion and a convex portion. The second bracket 120 is at least partially accommodated in the groove 140, and the longitudinal center axis II of the first bracket 110 is parallel or approximately parallel to the longitudinal center axis II-II of the second bracket 120. Among them, approximately parallel means that the angle between the longitudinal center axis II and the longitudinal center axis II-II is greater than 0° but less than 10°.

[0051] Among them, the first stent 110 and the second stent 120 are made of materials with good biocompatibility and good elasticity. For example, nitinol, stainless steel, etc. The membrane 130 is made of a thin film material with good biocompatibility. For example, PET, PTFE, etc. The combination or fixation method of the membrane 130 and the first stent 110 is not limited. For example, it can adopt the high-temperature pressing method or the suture fixation method. The membrane 130 can be a single-layer structure or a multi-layer structure.

[0052] In one embodiment, the second stent 120 is completely received in the groove 140, and the outer surface of the second stent 120 away from the bottom surface 140a of the groove 140 is flush with the outer surface of the first stent 110, as Figure 1 shown, that is, the cross-section of the second stent 120 and the first stent 110 in the opening direction of the groove 140 is coplanar (this cross-section is parallel to the longitudinal central axis I-I and the longitudinal central axis II-II), and the entire covered stent 100 has a uniform outer diameter. Or, the outer surface of the second stent 120 away from the bottom surface 140a of the groove 140 is lower than the opening end of the groove 140, that is, the outer diameter of the second stent 120 is smaller than the depth of the groove 140. In one embodiment, the difference between the outer diameter of the second stent 120 and the depth of the groove 140 (or the distance between the cross-section of the second stent 120 parallel to the longitudinal central axis II-II and the end surface of the opening end of the groove 140) does not exceed 25% of the outer diameter of the second stent 120, so as to avoid using a groove 140 with too large a depth, which may block the main blood vessel and affect the blood flow of the main blood vessel. In another embodiment, the second stent 120 is partially received in the groove 140, that is, a part of the second stent 120 protrudes out of the groove 140. The height of the protruding part from the end surface of the opening end of the groove 140 does not exceed 10% of the outer diameter of the second stent 120, so as to avoid affecting the anchoring of the first stent 110 of the covered stent 100 to the main blood vessel. Or, to avoid excessive extrusion of the blood vessel wall by the second stent 120, resulting in blood vessel wall damage.

[0053] The first stent 110 has a first end 110A and a second end 110B that are axially opposite. The first stent 110 includes a plurality of first corrugations 112 and at least one second corrugation 114. The plurality of first corrugations 112 are located at the first end 110A and the second end 110B of the first stent 110. At least one second corrugation 114 is located between the first corrugations 112 at both ends and is radially opposite to the groove 140. That is, the second corrugation 114 is located in the middle of the first stent 110.

[0054] In one embodiment, the first corrugation 112 has a Z-shaped corrugation structure. The Z-shaped corrugation structure is a closed-loop structure with wave peaks and wave valleys formed by connecting a plurality of first wave rods (not labeled in the figure) end to end. There is at least one first corrugation 112 at the first end 110A and at least one first corrugation 112 at the second end 110B. In one embodiment, there are two or more first corrugations 112 at the first end 110A and two or more first corrugations 112 at the second end 110B. When the number of first corrugations 112 at both ends is greater than or equal to 2, the two or more first corrugations 112 at each end are arranged at intervals along the axial direction (the extending direction of the longitudinal central axis I-I). Moreover, the two or more first corrugations 112 at each end are connected by an axial connecting member (not shown in the figure) or there is no connecting member between the plurality of first corrugations 112, and they are connected together by the film 130. In other embodiments, the number of first corrugations 112 at the first end 110A and the number of first corrugations 112 at the second end 110B may be equal or unequal.

[0055] It should be noted that between the plurality of first corrugations 112 on both sides of the second corrugation 114, the waveform, wave height, wave number, etc. may be the same or different. The number of first corrugations 112 on both sides of the second corrugation 114 may be equal or unequal.

[0056] The radial dimension of the second corrugation 114 (the distance between the two points with the largest distance in the radial direction, the same below. For example, the diameter) is smaller than the radial dimension of the first corrugation 112 (for example, the diameter), so that after the film 130 is coated on the first bracket 110, a lumen structure with openings at both ends and a groove 140 in the middle is formed.

[0057] In one embodiment, the second corrugation 114 is a closed-loop structure with wave peaks and wave valleys formed by connecting a plurality of second wave rods (not labeled in the figure), as Figure 3 shown, but the diameter of the second corrugation 114 is smaller than the diameter of the first corrugation 112. The second corrugation 114 is opposite to the bottom surface 140a of the groove 140 and radially supports the area of the film 130 located on the bottom surface 140a. The second corrugation 114 is fixedly connected to the area of the film 130 located on the bottom surface 140a. Alternatively, the second corrugation 114 is fixedly connected to at least one of the parts of the film 130 located on the side surfaces 140b, 140c, 140d, and 140e, but is not connected to the part of the film 130 located on the bottom surface 140a. The connection methods include but are not limited to directly fixedly connecting the two by means such as gluing and suturing. Alternatively, a connecting member is used to indirectly connect the second corrugation 114 and the film 130.

[0058] In one embodiment, as Figure 4As shown, the second wave ring 114 is a closed-loop structure, including a first non-closed wave ring 1142 and a first closing part 1144. Please refer to Figure 5 and Figure 6 , the first non-closed wave ring 1142 is a non-closed structure with wave peaks and wave valleys formed by connecting multiple wave rods (not labeled in the figure) end to end and with non-connected ends. In one embodiment, when the bottom surface 140a of the groove 140 is a plane, the first non-closed wave ring 1142 is a structure of 1 / 2 to 3 / 4 of a circumference. When the bottom surface 140a of the groove 140 is a concave surface, the first non-closed wave ring 1142 is 5 / 9 to 8 / 9 of a circumference. When the bottom surface 140a of the groove 140 is a concave surface, a non-closed wave ring 1142 is 1 / 4 to 5 / 9 of a circumference. The two ends of the first closing part 1144 are respectively connected to the two free ends of the first non-closed wave ring 1142 to form a closed-loop structure. The first closing part 1144 is a rod structure, including a straight rod 1144A. The straight rod 1144A is opposite to the bottom surface 140a. The straight rod 1144A of the second wave ring 114 with this structure has a planar area, which can be well matched with the bottom surface 140a of the groove 140 to radially support the film 130 in the area of the bottom surface 140a well, which is beneficial to maintaining the bottom surface 140a of the groove 140 as a plane or approximately a plane, thus being beneficial to maintaining the shape of the groove 140 and avoiding the film 130 in the area of the groove 140 from fitting the opening of the branch blood vessel due to the deformation of the groove 140, thereby avoiding the phenomenon of blood flow obstruction in the branch blood vessel.

[0059] The second wave ring 114 is fixedly connected to the area of the film 130 located on the bottom surface 140a through the straight rod 1144A. It can also be fixedly connected to the inner surface of the film 130 through other parts, and the straight rod 1144A is not fixedly connected to the area of the film 130 located on the bottom surface 140a, that is, the groove 140 only overlaps on the straight rod 1144A of the second wave ring 114, and is not fixed by means such as gluing or sewing.

[0060] In one embodiment, the first closing part 1144 further includes two arc rods 1144B respectively connected to the two ends of the straight rod 1144A, and the ends of the two arc rods 1144B far from the straight rod 1144A are respectively connected to the two free ends of the first non-closed wave ring 1142. The arc rods 1144B are provided to form a transition to avoid stress concentration, thereby avoiding the risk of fracture at the connection part between the first closing part 1144 and the first non-closed wave ring 1142.

[0061] In one embodiment, the first closing part 1144 is omitted, that is, the second wave ring 114 only includes the first non-closed wave ring 1142, making the second wave ring 114 a non-closed-loop structure, as Figure 7 shown. The two free ends of the second wave ring 114 are in a blunt structure to avoid piercing the film 130. In one embodiment, as Figure 8and Figure 9 As shown, the two free ends of the second wave loop 114 are respectively curled towards the cavity direction or the outside of the cavity to form two passivation structures 1143. In another embodiment, the passivation structure can be in other forms. For example, it can be a spherical structure fixed to the free ends of the second wave loop 114 by welding or other fixing means.

[0062] Please return to Figure 1 , in one embodiment, the second bracket 120 includes at least one third wave loop 122. In one embodiment, the number of the third wave loops 122 is multiple, and the multiple third wave loops 122 are arranged in the groove 140 at intervals along the longitudinal central axis II-II. In another embodiment, the multiple third wave loops 122 are arranged in the groove 140 without intervals along the longitudinal central axis II-II.

[0063] Please refer to Figure 10 , in one embodiment, the third wave loop 122 is a closed-loop structure. The third wave loop 122 includes a second non-closed wave loop 1222 and a second closing part 1224. Please refer to Figure 11 together. The second non-closed wave loop 1222 is a non-closed-loop structure formed by connecting the heads and tails of multiple wave rods 1222a and the ends are not connected, so that the second non-closed wave loop 1222 has two free ends. In one embodiment, when the bottom surface 140a of the groove 140 is a plane, the second non-closed wave loop 1222 is a 1 / 2 - 3 / 4 circumferential structure. When the bottom surface 140a of the groove 140 is a concave surface, the first non-closed wave loop 1142 is a 5 / 9 - 8 / 9 circumferential. When the bottom surface 140a of the groove 140 is a concave surface, a non-closed wave loop 1142 is a 1 / 4 - 5 / 9 circumferential. The second closing part 1224 includes a straight connecting rod 1224A and two arc-shaped transition rods 1224B respectively connected to the two ends of the straight connecting rod 1224A. The two ends of the two arc-shaped transition rods 1224B are respectively connected to the two free ends of the second non-closed wave loop 1222, thereby forming a closed-loop third wave loop 122.

[0064] The third wave loop 122 is received in the groove 140, and the second closing part 1224 of the third wave loop 122 is arranged on the bottom surface 140a of the groove 140. More specifically, the straight connecting rod 1224A of the second closing part 1224 is arranged on the bottom surface 140a of the groove 140, and the radian of the second non-closed wave loop 1222 matches the radian of the first wave loop 112 of the first bracket 110, so that the profile of the covered stent 10 is a hollow cylindrical structure or approximately a hollow cylindrical structure.

[0065] Therefore, the third wave loop 122 includes a second non-closed wave loop 1222 and a second closed portion 1224, which can not only match the shape of the groove 140, but also match the curvature of the first wave loop 112, thereby providing better radial support for the groove 140 and enabling the outer contour of the covered stent 100 to have a smooth transition, so that the contour of the covered stent 100 is a hollow cylindrical structure or approximately a hollow cylindrical structure, facilitating delivery and release.

[0066] In one embodiment, the third wave loop 122 is fixed to the side surface 140d through a wave rod 1222a, realizing the fixation of the third wave loop 122 in the groove 140. In one embodiment, as Figure 12 shown, when the third wave loop 122 is in the position state in the groove 140, the wave rod 1222a of the third wave loop 122 is fixedly connected to the edge line of the side surface 140d, and the other wave rod 1222a of the third wave loop 112 is fixedly connected to the edge line of the side surface 140c.

[0067] In one embodiment, please refer to Figure 13 , the structure of the third wave loop 122 omits the straight connecting rod 1224A, that is, the third wave loop 122 includes a second non-closed wave loop 1222 and two arc-shaped transition rods 1224B respectively connected to the two free ends of the second non-closed wave loop 1222, so that the third wave loop 122 has an opening and is a non-closed loop structure. The third wave loop 122 is fixed in the groove 140 by fixedly connecting the wave rod 1222a of the third wave loop 122 to the edge lines of the side surface 140d and the side surface 140c. Alternatively, the third wave loop 122 is fixed in the groove 140 by connecting the wave rod 1222a of the third wave loop 122 to the side surface 140d and the side surface 140c, but the connection part is not necessarily located on the edge lines of the side surface 140d and the side surface 140c.

[0068] Omitting the straight connecting rod 1224A is beneficial to reducing the metal consumption. Moreover, when subjected to a radial force acting towards the bottom surface 140a of the groove 140, the second non-closed wave loop 1222 of the third wave loop 122 can squeeze the bottom surface 140a of the groove 140 to prevent the bottom surface 140a of the groove 140d from fitting the opening part of the branch blood vessel.

[0069] The free end of each arc-shaped transition rod 1224B is a passivation structure to avoid damaging the film 130. The form of the passivation structure is not limited. For example, the passivation structure can be the same as the passivation structure of the second wave loop 114. Details are not described herein again.

[0070] In another embodiment, please refer to Figure 14, the third wave loop 122 is a closed-loop structure with wave peaks and wave valleys formed by connecting multiple wave rods end to end, that is, the third wave loop 112 is a cylindrical wave loop. The contact area between the cylindrical third wave loop 122 and the bottom surface 140a of the groove 140 is small, which is beneficial to the subsequent windowing operation.

[0071] In one embodiment, the cylindrical third wave loop 122 is fixedly connected to the side surfaces 140c and 140d of the groove 140 through wave rods opposite in the radial direction, and the bottom of the third wave loop 122 is not connected to the bottom surface 140a of the groove 140.

[0072] It should be noted that when the number of the third wave loops 122 is multiple, the multiple third wave loops 122 are arranged at intervals along the axial direction (the extending direction of the longitudinal central axis II-II). Adjacent third wave loops 122 can be connected by an axial connecting member (not shown in the figure), or can be not connected. Setting the axial connecting member can stabilize the position where the third wave loop 122 is released.

[0073] When adjacent third wave loops 122 are connected by an axial connecting member, the axial connecting member can be a rigid connecting member or a flexible connecting member.

[0074] The form of the rigid connecting member is not limited, and it can be a straight rod, a special-shaped rod, etc. made of metal material. Please refer to Figure 15 , in one embodiment, the axial connecting member 124 is used to connect the adjacent third wave loops 122. The axial connecting member 124 is a straight rod-shaped rigid connecting member. And when the covered stent 100 is bent, a large bend side and a small bend side are formed, and the axial connecting member 124 is located on the large bend side so as not to affect the bending of the covered stent 100. In one embodiment, the number of the axial connecting members 124 does not exceed 2. In one embodiment, the number of the axial connecting members 124 is 1, that is, only one axial connecting member 124 is used to connect two adjacent third wave loops 122.

[0075] Please refer to Figure 16 , in one embodiment, the axial connecting member 124 is a flexible connecting member. The position of the flexible connecting member is not limited, and the number is also not limited. In the embodiment, the number of the flexible connecting members is 3, and the three flexible connecting members are located on the side of the second stent 120 away from the bottom surface 140a of the groove 140.

[0076] In another embodiment, please refer to Figure 17 , the second stent 120 is an integral metal skeleton. For example, the second stent 120 is a lumen mesh structure formed by braiding metal wires, or a lumen mesh structure formed by cutting a metal tube. Or, the second stent 120 includes multiple non-spaced third wave loops 122 ( Figure 17Not shown), the peaks and valleys of two adjacent third corrugated loops 122 are axially opposite and connected, such that the peaks and valleys of each third corrugated loop 122 are no longer in a state with free ends. The second stent 120 with this structure is an integral structure, which can avoid the phenomenon that the free ends of the peaks and / or valleys of a single corrugated loop are easily pushed into the branch blood vessel, thereby avoiding damage to the branch blood vessel caused by a single corrugated loop and improving the safety of use.

[0077] In one embodiment, the bottom of the second stent 120 is connected to the bottom surface 140a of the groove 140. In another embodiment, the side surface of the second stent 120 is connected to the side surfaces 140c and 140d of the groove 140.

[0078] In another embodiment, as Figure 17 shown, the second stent 120 is connected to the membrane 130 or the first corrugated loop 112 through the axial connecting rod 150. One end of the axial connecting rod 150 is connected to the first end of the second stent 120, and the other end axially extends outside the groove 140 and is connected to the membrane 130 or the first corrugated loop 112.

[0079] There are at least two axial connecting rods 150. When there are two axial connecting rods 150, the two axial connecting rods 150 are located at the axially opposite ends of the second stent 120, and both of the two axial connecting rods 150 are located at the open end of the groove 140. One end of each axial connecting rod 150 is connected to the second stent 120, and the other end axially extends from the open end of the groove 140 outside the groove 140a and is connected to the membrane 130 or the first corrugated loop 112.

[0080] Moreover, the bottom of the second stent 120 (the part close to the bottom surface 140a of the groove 140) is not fixedly connected to the bottom surface 140a of the groove 140, so as to facilitate adjusting the relative position between the bottom of the second stent 120 and the bottom surface 140a of the groove 140, thereby facilitating the subsequent operations of windowing and implanting the branch stent.

[0081] The form of the axial connecting rod 150 is not limited. For example, it can be a straight rod, a special-shaped rod, etc.

[0082] It can be understood that in the embodiment where the second stent 120 is an integral metal framework, the shape of the cross-section of the second stent 120 is not limited. For example, it can be Figure 10 the structure including the second non-closed corrugated loop 1222, the straight connecting rod 1224A and the arc transition rod 1224B as shown, or it can be Figure 13 the structure including the second non-closed corrugated loop 1222 and the arc transition rod 1224B but omitting the straight connecting rod 1224A as shown. It can also be Figure 14 the cylindrical structure as shown. Details are not elaborated here.

[0083] Please refer toFigure 18 , in another embodiment, a first window 125 is formed at the bottom of the second stent 120 (at a position close to the bottom surface 140a of the groove 140). The first window 125 is located in the middle region of the second stent 120. Since there is no obstruction or interference of the metal framework in the window 124 part, the subsequent operations of windowing and implanting the branch stent are made easier. Moreover, it is beneficial to reduce the usage amount of metal. At the same time, since the radial dimension of the compressed second stent 120 is reduced, the radial dimension of the compressed covered stent 100 is thus reduced, so that a smaller-sized delivery sheath can be used for delivery, resulting in less damage to the patient or being applicable to more patients.

[0084] Please refer to Figure 19 , in another embodiment, a second window 126 is further formed at a position of the second stent 120 that is radially opposite to the first window 125. The first window 125 and the second window 126 are opposite to each other, that is, the middle region of the second stent 120 has no metal framework. In this way, through the support of the second window 126 and the metal framework at the edge of the second window 126, when the covered stent 100 is implanted into the blood vessel, the metal framework presses the bottom surface 140a of the groove 140 to prevent the bottom surface 140a of the groove 140 from displacing towards the direction close to the branch blood vessel opening and fitting the branch opening part. Moreover, while ensuring the supporting effect, the subsequent operations of windowing and implanting the branch stent are more convenient. Also, the usage amount of metal is smaller, and the radial dimension of the compressed covered stent 100 is smaller, so that a smaller-sized delivery sheath can be used for delivery, resulting in less damage to the patient or being applicable to more patients.

[0085] In another embodiment, when the second window 126 is omitted, the first window 125 can be formed at the bottom of the second stent 120, or the first window 125 can also be formed on the side of the second stent 120 opposite to the bottom (i.e., the top of the second stent 120).

[0086] In one embodiment, a through hole is formed in the groove 140 to penetrate the side surface of the groove 140 for blood flow to pass through. In one embodiment, at least one of the bottom surface 140a, side surfaces 140b, 140c, 140d, and 140e of the groove 140 is provided with a through hole. Specifically, please refer to Figure 20 , in one embodiment, a first through hole 142 is formed in the groove 140 to penetrate the side surface 140b. Blood flow can flow from the main blood vessel to each branch blood vessel through the first through hole 142. When the lesion does not reach the root of the branch artery, there is no need to implant a branch stent subsequently, which is more economical for the patient.

[0087] When the first window 125 is opened at the top of the second bracket 120, the first through hole 142 and the first window 125 can serve as channels for the branch bracket. The branch bracket enters the second bracket 120 from the first through hole 142 and extends out of the second bracket 120 from the first window 125.

[0088] Please refer to Figure 21 , in one embodiment, a second through hole 144 penetrating the side surface 140e is provided on the groove 140, which can also enable blood flow to flow from the main blood vessel to each branch blood vessel through the second through hole 144. When the lesion does not accumulate to the root of the branch artery, there is no need to implant a branch bracket subsequently.

[0089] It should be noted that the first through hole 142 and the second through hole 144 can exist simultaneously, or either the first through hole 142 or the second through hole 144 can exist alternatively.

[0090] Please refer to Figure 22 , in one embodiment, a third through hole 146 penetrating the bottom surface 140a is provided on the groove 140, which can also enable blood flow to flow from the main blood vessel to each branch blood vessel through the third through hole 146. When the lesion does not accumulate to the root of the branch artery, there is no need to implant a branch bracket subsequently. Or, when the third through hole 146 is provided, when implanting the branch bracket subsequently, there is no need to perform an in-situ windowing operation on the bottom surface 140a, but directly send the branch bracket through the third through hole 146.

[0091] It should be noted that when the third through hole 146 is provided, at least one of the first through hole 142 and the second through hole 144 can be omitted, or both can be retained.

[0092] It should also be noted that the shapes and numbers of the first through hole 142, the second through hole 144, and the third through hole 146 are not limited, as long as blood flow can pass through and no adverse effects are produced on the overall structure of the groove 140.

[0093] In one embodiment, the first through hole 142, the second through hole 144, and the third through hole 146 are all circular holes, and the numbers of the first through hole 142 and the second through hole 144 are both one, and the number of the third through hole 146 is 3.

[0094] The following uses the Figure 1 illustrated embodiment to describe the usage method of the covered stent 100. As Figure 23As shown, the diseased blood vessel 1 is a blood vessel in the aortic arch portion, and an arterial dissection 2 occurs on one side of the arch portion opposite to the branch blood vessel. After the covered stent 100 is implanted into the diseased blood vessel 1, the groove 140 corresponds to the branch blood vessel portion. Specifically, all three branch blood vessels 101 are radially opposite to the groove 140. After the covered stent 100 is implanted into the diseased blood vessel 1, the covered stent 100 bends along with the natural curvature of the diseased blood vessel 1. During the bending process, the portion where the groove 140 is located also bends, resulting in a tendency for the bottom surface 140a ( Figure 23 not shown) of the groove 140 to bulge towards the branch blood vessel 101. However, due to the radial support performance of the second stent 120 itself, it can provide a reverse support force to the bottom surface 140a of the groove 140 to limit the tendency of the bottom surface 140 of the groove 140 to bulge towards the branch blood vessel 101, so that the bottom 140a of the groove 140 can be away from the opening of the branch blood vessel 101, thereby avoiding the covered membrane 130 from blocking the opening of the branch blood vessel 101. Please refer to Figure 24 together. Then, using the in-situ fenestration technique, a window is opened through the bottom surface 140a ( Figure 23 not shown) of the groove 140, and the branch stent 200 is sent into the branch blood vessel 101 through this fenestration and the branch stent 200 is released to establish a blood flow channel between the branch blood vessel 101 and the diseased blood vessel 1.

[0095] Due to the radial support of the second stent 120, the shape of the groove 140 can be better maintained, so that the bottom surface 140a of the groove 140 is kept at a sufficient distance from the opening of the branch blood vessel 200 to facilitate in-situ fenestration and implantation of the branch stent 200.

[0096] Moreover, since the bottom of the second stent 120 is not fixedly connected to the bottom surface 140a of the groove 140, during the process of in-situ fenestration and implantation of the branch stent 200, the position of the third corrugated ring 122 can be adjusted as needed, making the operation more convenient, which is conducive to improving the position accuracy and shortening the operation time. At the same time, when the release of the branch stent 200 is completed, the third corrugated ring 122 is fixed around the branch stent 200 to form a stable support and maintain the stability of the position of the branch stent 200 to keep the branch blood vessel unobstructed continuously.

[0097] It should be noted that the second corrugated rings 114 of different embodiments and the third corrugated rings 122 of different embodiments are introduced above respectively, and the second corrugated rings 114 of different embodiments and the third corrugated rings 122 of different embodiments can be combined arbitrarily.

[0098] For example, Figure 7 the second corrugated ring 114 shown can be combined with Figure 10The third wave ring 122 combination shown, through the straight connecting rod 1224A of the third wave ring, is relatively well-matched with the bottom surface 140a of the groove 140, and can better squeeze the bottom surface 140a of the groove 140 to prevent the bottom surface 140a from fitting the opening of the branch blood vessel. Moreover, the second wave ring 114 is an open structure, which is beneficial to reducing the metal usage and the radial dimension of the compressed covered stent 100.

[0099] For another example, Figure 4 The second wave ring 114 shown can be combined with Figure 10 The third wave ring 122 shown, such that the straight rod 1144A of the second wave ring 114 is opposite to the straight connecting rod 1224A of the third wave ring 122 and they cooperate with each other.

[0100] For another example, Figure 7 The second wave ring 114 shown can be combined with Figure 13 The third wave ring 122 shown. The third wave ring 122 exerts a radial supporting force on the groove 140 through the second non-closed wave ring 1222. This combination uses less metal.

[0101] For another example, Figure 7 The second wave ring 114 shown can be combined with Figure 14 The third wave ring 122 shown. The third wave ring 122 exerts a radial supporting force on the groove 140 through the second non-closed wave ring 1222.

[0102] For another example, Figure 7 The second wave ring 114 shown can be combined with Figure 17 The second stent 120 shown. The second stent 120 provides a radial supporting force for the groove 140, and the second stent 120 with this structure can avoid the risk that the third wave ring 122 with a free end at the end can damage the inner wall of the branch blood vessel.

[0103] For another example, Figure 7 The second wave ring 114 shown can be combined with Figure 18 or Figure 19 The third wave ring 122 shown.

[0104] For another example, the second wave ring 114 shown in Embodiment 4 can be combined with Figure 13 The third wave ring 122 shown. By squeezing the bottom surface 140a of the groove 140 through the straight rod 1144A of the second wave ring 114, the metal usage is reduced at the same time, that is, the radial dimension of the compressed covered stent 100 is reduced.

[0105] Other combination methods will not be elaborated one by one.

[0106] Regardless of how the second wave ring 114 with different structures and the third wave ring 122 with different structures are combined, in one embodiment, the radial support strength P1 of the first stent 110 and the radial support strength P2 of the second stent 120 are not equal.

[0107] In one embodiment, P1 and P2 satisfy: 1 / 2 < (P2 / P1) < 1, that is, the radial support strength P2 of the second stent 120 is less than the radial support strength P1 of the first stent 110, but P2 should be large enough, greater than 0.5 times of P1, so that when the first stent 110 and the second stent 120 are subjected to equal radial compression forces, the reduction amount of the radial dimension of the second stent 120 after being radially compressed is not too large, to facilitate the windowing operation.

[0108] In one embodiment, P1 and P2 satisfy: 1 ≤ (P2 / P1) ≤ 2, that is, the radial support strength P2 of the second stent 120 is greater than or equal to the radial support strength P1 of the first stent 110, and P2 is less than 2 times of P1, so that when the first stent 110 and the second stent 120 are subjected to equal radial compression forces, the reduction amount of the radial dimension of the first stent 110 after being radially compressed is not too large, to keep the blood flow through the first stent 110 unobstructed.

[0109] It should be noted that the radial support strength is equal to the ratio of the radial support force to the axial length. For example, when the radial support force received by the second stent 120 is F2 and the axial length of the second stent 120 is L2, then P2 = F2 / L2. When the radial support force received by the first stent 110 is F1 and the axial length of the first stent 110 is L1, then P1 = F1 / L1. Among them, L1 is the axial length of the part of the first stent 110 that is radially opposite to the second stent 120, and L1 = L2.

[0110] It should also be noted that the radial support force F1 of the first stent 110 and the radial support force F2 of the second stent 120 can be tested by the flat plate compression method. Or, the radial support force F1 of the first stent 110 and the radial support force F2 of the second stent 120 are tested by the radial compression method. That is, when comparing the magnitudes of F1 and F2, the same test method is used to test F1 and F2 under the same conditions. For example, the magnitudes of the radial support force F1 when the first stent 110 is compressed by 50% and the radial support force F2 when the second stent 120 is compressed by 50% are respectively tested by the radial compression method. When using the flat plate compression method, two flat plates are used to compress the two sides of the stent respectively. The two flat plates are parallel, and the two flat plates are symmetrically arranged with respect to the longitudinal central axis. And the two flat plates are respectively the two tangent planes of the stent.

[0111] The radial supporting force F1 of the first stent 110 is related to parameters such as the rod diameter, the number of waves, and the angle at the wave trough or wave peak of the second wave loop 114. The radial supporting force F2 of the second stent 120 is related to parameters such as the rod diameter, the number of waves, and the angle at the wave trough or wave peak of the third wave loop 122, which can be adjusted by those skilled in the art according to needs.

[0112] Please go back to Figure 1 In one embodiment, the covered stent 100 further includes an anchoring stent 160. The anchoring stent 160 is located at the first end 110A of the first stent 110 and is connected to the first wave loop 112 or the covering film 130. The anchoring stent 160 is a bare stent without any covering film. The anchoring stent 160 includes at least one anchoring wave loop 162. When the number of the anchoring wave loops 162 is multiple, the multiple anchoring wave loops 162 are arranged at intervals along the longitudinal central axis I-I.

[0113] When the covered stent 100 is implanted into a blood vessel, the anchoring stent 160 is located at the proximal end of the covered stent 100. The anchoring stent 160 is provided to further improve the anchoring performance of the end of the covered stent 100.

[0114] In one embodiment, the number of the first wave loops 110 at the first end 110A is one. And when the groove 140 is only radially opposite to two branch blood vessels 101 (the two branch blood vessels 101 near the second end 110B), through the cooperation of one first wave loop 110 and the anchoring stent 160, the anchoring of the proximal end of the covered stent 100 is realized. And since the anchoring stent 160 is a bare stent, it will not completely block the opening of the third branch blood vessel 101, and there is no need to perform the operations of fenestration and implanting the branch stent 200.

[0115] In one embodiment, the wave rod length of the anchoring wave loop 162 is less than that of the first wave loop 162, and the number of waves of the anchoring wave loop 162 is greater than that of the first wave loop 162, so that the anchoring performance of the anchoring stent 160 is better.

[0116] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0117] The above-described embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A covered stent, characterized in that, it includes a first stent, a second stent and a covering film. The covering film is wrapped around the first stent to form a lumen structure with a groove in the middle. The first stent includes a plurality of first corrugated rings and at least one second corrugated ring. The plurality of first corrugated rings are located at both ends of the first stent, and the second corrugated ring is located in the middle of the first stent, and the second corrugated ring is radially opposite to the groove; the second stent is a mesh structure formed by weaving metal wires or cutting a metal tube, or the second stent includes a plurality of third corrugated rings arranged at intervals or non-intervals. At least part of the second stent is received in the groove and connected to the first stent, and the longitudinal central axis of the first stent and the longitudinal central axis of the second stent are parallel or the angle between the longitudinal central axis of the first stent and the longitudinal central axis of the second stent is greater than 0° but less than 10°. The second stent has radial support performance so that the bottom surface of the groove keeps a distance from the opening of the branch blood vessel.

2. The covered stent according to claim 1, characterized in that, the second corrugated ring is a closed-loop structure with a wave crest and a wave trough or an open-loop structure with a wave crest and a wave trough.

3. The covered stent according to claim 2, characterized in that, when the second corrugated ring is a closed-loop structure with a wave crest and a wave trough, the second corrugated ring includes a first non-closed corrugated ring and a first closed part. The first non-closed corrugated ring is an open-loop corrugated ring with a wave crest and a wave trough. The open-loop corrugated ring has two free ends. The first closed part includes a straight rod, and both ends of the straight rod are directly or indirectly connected to the two free ends; when the second corrugated ring is an open-loop structure with a wave crest and a wave trough, the second corrugated ring is an open-loop corrugated ring with a wave crest and a wave trough. The open-loop corrugated ring has two free ends, and the two free ends are blunt structures.

4. The covered stent according to claim 1, characterized in that, the second stent includes at least one third corrugated ring, and the third corrugated ring is a closed-loop structure with a wave crest and a wave trough or an open-loop structure with a wave crest and a wave trough.

5. The covered stent according to claim 4, characterized in that, there are a plurality of the third corrugated rings, and the plurality of third corrugated rings are arranged at intervals or non-intervals along the axis.

6. The covered stent according to claim 4 or 5, characterized in that, when the third corrugated ring is a closed-loop structure with a wave crest and a wave trough, the third corrugated ring includes a second non-closed corrugated ring and a second closed part. The second non-closed corrugated ring is an open-loop corrugated ring with a wave crest and a wave trough. The open-loop corrugated ring has two free ends. The second closed part includes a straight connecting rod, and both ends of the straight connecting rod are directly or indirectly connected to the two free ends; when the third corrugated ring is an open-loop structure with a wave crest and a wave trough, the third corrugated ring is an open-loop corrugated ring with a wave crest and a wave trough. The open-loop corrugated ring has two free ends, and the two free ends are blunt structures.

7. The covered stent according to claim 4 or 5, characterized in that, The groove includes a bottom surface and a side surface surrounding the bottom surface. The third corrugation is at least partially received in the groove, and the third corrugation is not fixedly connected to the bottom surface.

8. The covered stent according to claim 1, wherein, the second stent is an integrally formed stent woven by braided wires or an integrally formed stent formed by cutting.

9. The covered stent according to claim 8, wherein, a first window is provided on one side of the second stent.

10. The covered stent according to claim 8, wherein, the groove includes a bottom surface and a side surface surrounding the bottom surface. A first window is provided on a side of the second stent close to the bottom surface. The second stent is further provided with a second window, and the first window and the second window are opposite to each other in the radial direction.

11. The covered stent according to claim 1, wherein, the groove includes a bottom surface and a side surface surrounding the bottom surface, and at least one of the bottom surface and the side surface is provided with a through hole.

12. The covered stent according to claim 1, wherein, the radial support strength of the first stent is P1, the radial support strength of the second stent is P2, and P1 and P2 satisfy: 1 / 2 < (P2 / P1) < 1; or, P1 and P2 satisfy: 1 ≤ (P2 / P1) ≤ 2.

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