CN206934211U - Branch type overlay film frame - Google Patents

Abstract

A bifurcated covered stent, comprising a tubular main body and side branches communicating with the tubular main body, the tubular main body includes a first bare stent and a first membrane disposed on the first bare stent, the first bare stent includes at least one non-end The side branch includes a second coating, the second coating is connected to the first coating, and the interface between the first coating and the second coating is provided with an expansion ring distributed along the periphery of the interface, and the expansion ring At least partly on the circumferential surface of the tubular body provided with the non-end wave-shaped ring. The aforementioned bifurcated stent graft is provided with an expansion ring at the interface, and the expansion ring is at least partially located on the circumferential surface of the tubular body provided with a non-end wave-shaped ring. After the stent is released, the expansion ring can follow the first bare The self-expansion of the stent expands radially to maintain the radial width of the interface, so as to ensure that the blood flow smoothly flows from the tubular body through the interface into the side branch, so that the blood flow in the side branch is smooth and sufficient, and it is easy for the guide wire to enter .

Description

bifurcated stent graft

technical field

The utility model relates to the technical field of medical instruments, in particular to a bifurcated membrane-covered stent.

Background technique

Aneurysm is a clinically common vascular disease, which mostly occurs in the elderly. This disease can easily lead to aortic aneurysm rupture, which poses a great threat to the life of patients. General surgery was once considered the only way to treat aortic aneurysm. The only way, but this method is extremely dangerous.

With the continuous development of medical technology, the use of minimally invasive surgery to implant covered stents into the human body to treat aortic aneurysms and dissecting aneurysms is being used more and more. This treatment method compresses the artificial covered stent into the delivery device, guides it into the human body along the previously implanted guide wire, releases the covered stent to the lesion, isolates the aneurysm cavity and forms a new blood flow channel, and the aneurysm is lost. After the blood supply, the remaining blood in the aneurysm gradually thrombuses and muscularizes into vascular tissue, and the expanded aneurysm wall shrinks due to negative pressure, and gradually returns to its original state, thereby achieving the purpose of treating the aneurysm.

However, the vascular structure of the human body is complex, and there are many side branches. At the same time, individual patients are different. The length of the tumor may be very long, and the location of the tumor may also vary greatly. The situation near the branch is also more common. If the aneurysm is treated with a covered stent, the side branch blood vessel will often be occluded. Standardized straight-tube stent-grafts are difficult to meet the requirements, and side branch vessels often need to be customized for special vascular sites.

At present, a bifurcated stent graft has appeared, and different specifications of side branches and main body can be made according to the position and shape of the patient's aneurysm, and it is widely used in clinical practice. But this will bring new problems, for example, the side branch of the stent and the film connection port at the junction of the main body, because the film is generally a flexible material and has no supporting force, so it cannot maintain the shape of the interface itself, resulting in a flat position of the interface. Seams are not conducive to blood flow through the interface. Generally, there are two main structures of the metal bracket and the membrane between the main body and the side branches, one is through the metal corrugated across the main body and the side branches, and the other is that the main body and the side branches use independent metal corrugations. In these two ways, the former main body and the side branch metal bracket are integrated to ensure the interface shape of the side branch, but the one-piece metal bracket structure limits the flexibility between the side branch and the main body, and the latter main body and side branch bracket are separated. Independent metal stent structure, although there is good flexibility between the side branch and the main body, but the position of the side branch interface is not supported by the metal stent, and the interface shape is not good, which affects the subsequent surgical guide wire entering the side branch stent through the main body stent. Orbital process, and is also not conducive to the passage of blood flow.

Utility model content

Based on this, in view of the above problems, it is necessary to provide a bifurcated stent-graft to improve the contour shape of the side branch interface and make the blood flow of the side branch unobstructed.

A bifurcated covered stent comprising a tubular main body and side branches communicating with the tubular main body, the tubular main body includes a first bare stent and a first membrane disposed on the first bare stent, the first A bare stent comprising at least one non-terminal undulating annulus, the side branches comprising a second covering connected to the first covering, the first covering connected to the second covering The interface of the coating is provided with expansion rings distributed along the outer periphery of the interface, and the expansion rings are at least partially located on the circumferential surface of the tubular body provided with the non-end wave-shaped ring.

In one of the embodiments, the first bare stent further includes a proximal wave-shaped ring and a distal wave-shaped ring, and the at least one non-end wave-shaped ring is arranged on the proximal wave-shaped ring Between the distal wave-shaped ring, the non-end wave-shaped ring is an open ring, and the expansion ring is at least partially located at the opening of the non-end wave-shaped ring.

In one of the embodiments, the expandable ring is connected to the free end of the non-end wave-shaped ring.

In one embodiment, there are at least two non-end wave-shaped rings, and the expansion ring is connected to all free ends of the at least two non-end wave-shaped rings.

In one of the embodiments, the expansion ring includes an expansion part formed by a metal wire around the periphery of the interface and a movable part connected with the expansion part, and the expansion part is at least partly located in the non-end wave-shaped ring on the circumference of the object.

In one of the embodiments, the expandable ring has a highest point close to the proximal wave-shaped ring and a lowest point close to the distal wave-shaped ring, and the movable part is located between the lowest point and the The side of the line connecting the highest points.

In one embodiment, the line between the two ends of the movable part is parallel to the line between the lowest point and the highest point of the expansion ring.

In one of the embodiments, the movable part is a notch provided on the expansion ring.

In one of the embodiments, there are two gaps, and the two gaps cut the expansion ring into two expansion parts arranged along the longitudinal central axis of the tubular body, each of the expansion The two ends of the portion are respectively connected to two corresponding free ends of the non-end wave-shaped ring.

In one embodiment, the expansion part is an open-loop structure, and the two opposite ends of the expansion part first approach each other and then extend away from each other to form an overlapping area, and the stacked area forms the movable part .

In one of the embodiments, the end of the movable part is round and smooth.

In one of the embodiments, the movable part is a wave section provided on the expansion ring, and the wave section includes several waves.

In one of the embodiments, the number of the waveform segments is two, and the two waveform segments are arranged symmetrically.

In one of the embodiments, the waveform is at least one of M-shaped wave, Z-shaped wave or sine wave.

In one embodiment, the angle between the longitudinal central axis of the tubular body and the longitudinal central axis of the side branch is an acute angle, and the expansion ring is elliptical.

In the aforementioned bifurcated stent-graft, an expansion ring is provided at the interface, and the expansion ring is at least partially located on the circumferential surface of the tubular body provided with the non-end wave-shaped ring, and the expansion ring provides support for the interface. After the stent is released, the expansion ring can radially expand with the self-expansion of the first bare stent to maintain the radial width of the interface, so as to ensure that the blood flow smoothly flows from the tubular main body through the interface into the side branch, so that The blood flow in the side branches is smooth and sufficient, and the guide wire is easy to enter. At the same time, the tubular main body and the side branches can use independent bare stents, which can improve the flexibility between the side branches and the main body, and improve the adaptability of the stent.

Description of drawings

Fig. 1 is a schematic structural view of a bifurcated stent graft according to an embodiment of the present invention;

Fig. 2 is a structural schematic view of another perspective of the bifurcated stent graft shown in Fig. 1;

Fig. 3 is a structural schematic diagram of the expansion ring and the non-end wave ring of the bifurcated stent graft according to another embodiment of the present invention;

Fig. 4 is a schematic structural view of the expansion ring and the non-end wave ring of the bifurcated stent graft according to another embodiment of the present invention;

Fig. 5 is a structural schematic diagram of the expansion ring and the non-end wave ring of the bifurcated stent graft according to another embodiment of the present invention;

Fig. 6 is a structural schematic diagram of an expansion ring of a bifurcated stent graft according to another embodiment of the present invention;

FIG. 7 is a schematic structural view of an expansion ring of a bifurcated stent graft according to another embodiment of the present invention.

Detailed ways

In order to make the above purpose, features and advantages of the present utility model more obvious and understandable, the specific implementation of the present utility model will be described in detail below in conjunction with the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a full understanding of the present invention. However, the utility model can be implemented in many other ways different from those described here, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific implementation disclosed below .

It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or there may be an intervening element. 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 "vertical," "horizontal," "left," "right," and similar expressions are used herein for purposes of illustration only and are not intended to represent the only embodiments.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of this invention. The terminology used herein in the description of the utility model is only for the purpose of describing specific implementations, and is not intended to limit the utility model. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In the field of stent-grafts, after the stent-grafts are implanted into blood vessels, it is defined that the blood flow flows from the proximal end of the stent-grafts to the distal end of the stent-grafts.

In this application, "covered stent" refers to the structure of the surface of the bare stent covered with a thin film, and the bare stent refers to a structure including a plurality of corrugated rings without a thin film between the corrugated rings.

Referring to FIG. 1 , the bifurcated stent graft 10 includes a tubular body 100 and a side branch 200 communicating with the tubular body 100 . The tubular body 100 includes a first bare stent 101 and a first membrane 103 disposed on the first bare stent 101 . The first bare stent 101 comprises at least one non-end wave ring 102 . The side branch 200 includes a second coating 201 . The second coating 201 is connected to the first coating 103 . The interface 110 between the first membrane 102 and the second membrane 201 is provided with an expansion ring 120 distributed along the periphery of the interface 110, and the expansion ring 120 is at least partially located on the tubular body 100. The circumferential surface of the non-end wave ring 102.

In the present application, the circumferential surface of the wave-shaped ring refers to the area enclosed by the line connecting multiple crests and the line connecting multiple troughs of the wave-shaped ring and including the wave-shaped ring.

Specifically, a certain angle is formed between the longitudinal central axis of the tubular main body 100 and the longitudinal central axis of the side branch 200, and the junction of the side branch 200 and the tubular main body 100 forms an interface 110, that is, the first film 103 and the second The joints of the covering films 201 form the interface 110 . Specifically in this embodiment, the connection between the first coating 103 and the second coating 201 can be through sewing, bonding, or hot-melt sintering, or the first coating 103 and the second coating 201 can also be integrated. . Both the first covering film 103 and the second covering film 201 can adopt a biocompatible film structure, for example, use PET (Polyethyleneterephthalate, polyethylene terephthalate) or PTFE (Polytetrafluoroethene, polytetrafluoroethylene) as Laminating material. The bare stent 101 may use a metal wire, for example, braid or cut the metal wire into a desired waveform, and the metal wire may be a nickel-titanium alloy wire, such as a nickel-titanium alloy wire with a diameter of 0.40 mm.

Please continue to refer to FIG. 1 , the first bare stent 101 , the expansion ring 120 and the first membrane 103 are connected by suturing, and the number and positions of the suturing points 105 are determined according to actual needs.

Of course, in other embodiments, the bare stent 101 , the expansion ring 120 and the first membrane 103 may also be formed by membrane sintering or pasting. For example, the inner surface and the outer surface of the bare stent 101 can be covered with polytetrafluoroethylene film as a whole, and the bare stent 101 and the expansion ring 120 are both located in the middle of the two layers of covering films. The vinyl covers are bonded together, thereby securing the bare stent 101 and expandable ring 120 between the covers.

It should be noted that the diameter of the side branch 200 may be equal to or not equal to the diameter of the tubular main body 100 , for example, the diameter of the side branch 200 may be smaller than the diameter of the tubular main body 100 .

In this embodiment, the angle formed between the longitudinal central axis of the tubular body 100 and the longitudinal central axis of the side branch 200 is an acute angle, and the interface 110 is elliptical. It should be noted that, in other embodiments, the angle between the longitudinal central axis of the tubular body 100 and the longitudinal central axis of the side branch 200 is not limited thereto, and the shape of the interface 110 can also be other, for example, the side branch 200 The longitudinal central axis of the tubular body 100 may also be perpendicular to the longitudinal central axis of the tubular body 100, and the interface 110 is circular. Certainly, the interface 110 may also be other space closed curves.

Generally, the stent has a compressed state and a released state. The compressed stent is bound in the sheath of the delivery device for delivery in the blood vessel. After reaching the target disease site, it is released by self-expansion of each bare stent on each membrane. Usually, the diameter length of the released stent is slightly longer than that of the blood vessel, so that the stent closely adheres to the blood vessel wall and forms a new blood flow channel. It can be understood that since there is no bare support at the interface 110 between the tubular main body 100 and the side branch 200, the oval-shaped interface 110 is easily deformed into a flat seam-like interface, which not only easily narrows the blood flow channel, but also hinders the guide wire. Get in without a hitch. In the bifurcated stent graft 10, an expansion ring 120 is provided at the interface 110, and the expansion ring 120 is at least partially located on the circumferential surface of the tubular body 100 provided with the non-end wave ring 102, The expansion ring 120 provides support force for the interface 110. After the stent is released, the expansion ring 120 can radially expand with the self-expansion of the first bare stent 101 to maintain the radial width of the interface 110, thereby ensuring the smooth flow of blood from The inside of the tubular main body 100 flows into the side branch 200 through the interface 110, so that the blood flow in the side branch 200 is smooth and sufficient, and the guide wire is easy to enter. At the same time, the tubular main body 100 and the side branch 200 can adopt independent bare stents, which can improve the flexibility between the side branch 200 and the main body 100 and improve the adaptability of the stent.

Please continue to refer to FIG. 2 , the first bare stent 101 also includes a proximal waveform ring 1021 and a distal waveform ring 1023, and the at least one non-end waveform ring 102 is arranged on the proximal waveform between the ring 1021 and the distal wave-shaped ring 1023 . The non-end wave-shaped ring 102 is an open ring, and the expansion ring 120 is located at the opening of the non-end wave-shaped ring 102 .

Specifically, both the near-end waveform ring 1021 and the distal waveform ring 1023 are closed rings, and the non-end waveform ring 102 is similar in shape to the proximal waveform ring 1021 and the distal waveform ring 1023, And the arc-shaped peripheral surface of the non-end wave-shaped ring 102 is in the same plane as the peripheral surfaces of the proximal wave-shaped ring 1021 and the distal wave-shaped ring 1023 . The near-end waveform ring 1021, the distal waveform ring 1023 and the non-end waveform ring 102 can have the same or similar waveform shapes, for example, the waveform shapes can be Z-shaped waves, M-shaped waves or sine waves, etc. .

Further, the expansion ring 120 is connected to the free end of the non-end wave-shaped ring 102 . Further, the number of the non-end wave-shaped rings 102 is at least two, and the expansion ring 120 is connected to all free ends of the at least two non-end wave-shaped rings 102 . Specifically in this embodiment, please refer to FIG. 2 , the number of non-end wave-shaped rings 102 is two, and the two free ends of the non-end wave-shaped rings 102 near the near-end wave-shaped ring 1021 are both Ending at the trough position, the two free ends of the non-end wave-shaped ring 102 near the distal wave-shaped ring 1023 end at the peak position, and the expansion ring 120 is located at the opening of the two non-end wave-shaped rings 102 , the expansion ring 120 is connected to the four free ends of the two wave-shaped rings 102 .

It should be noted that there may be multiple non-end wave-shaped rings 102 , and the expansion ring 120 is located at openings of the non-end wave-shaped rings 102 . It can be understood that, in other embodiments, the expandable ring 120 may be connected to the free ends of all non-end wave-shaped rings 102, or may be selectively connected to the free ends of some non-end wave-shaped rings 102. , can also be disconnected from all the free ends of the non-end wave-shaped rings 102 .

Of course, in other embodiments, the expandable ring 120 may not be connected to the free end of the non-end wave-shaped ring 102, that is, there is a certain gap between the expandable ring 120 and the free end of the non-end wave-shaped ring 102. interval.

Specifically, the expansion ring 120 includes an expansion part 121 formed by a metal wire around the periphery of the interface 110 and a movable part 122 connected to the expansion part 121 . The expansion portion 121 is at least partially located on the circumferential surface of the non-end wave-shaped ring 102 . The expansion part 121 is used for self-expanding to maintain the contour shape of the interface 110 after the stent is released. The movable part 122 is connected with the non-end wave-shaped ring 102, so that when the non-end wave-shaped ring 102 is unconstrained and returns to the natural state, the movable part 122 can also be in the non-end wave-shaped ring. Driven by 102, the expansion ring 120 self-expands faster to maintain the contour shape of the interface 110, thereby more effectively ensuring that the blood flow smoothly from the tubular main body 100 through the interface 110 into the side branch 200, so that the side branch 200 blood The flow is clear, adequate, and easy for guidewire access.

In this embodiment, the expansion part 121 is a closed ring structure; the number of movable parts 122 is two, and the two movable parts 122 are respectively located on both sides of the expansion part 121; The two free ends of the two non-end wave-shaped rings 102 are connected, and the other movable part 122 is connected with the two free ends of the two non-end wave-shaped rings 102 on the other side of the expansion ring 120 .

Certainly, in other embodiments, the movable part 122 can also be omitted for the expansion ring 120, for example, other materials with better elasticity are used to form a circle around the outer circumference of the interface 110, such as an elastic ring made of nickel-titanium alloy, and the material itself has Closed ring made of swellable polymer material.

Further, referring to FIG. 2 , the expandable ring 120 has a highest point 123 close to the proximal wave-shaped ring 1021 and a lowest point 124 close to the distal wave-shaped ring 1023 , and the movable part 122 is located at One side of the line connecting the lowest point 124 and the highest point 123 .

Furthermore, at least one end point of the movable part 122 does not coincide with the highest point 123 and the lowest point 124 . For example, one end of the movable part 122 is located at the highest point 123 , and the height of the other end is higher than that of the lowest point 124 . As another example, one end of the movable part 122 is located at the lowest point 124 , and the height of the other end is lower than that of the highest point 123 . As another example, the height of one end of the movable part 122 is higher than the height of the lowest point 124, and the height of the other end is lower than the height of the highest point 123, so that the expansion ring 120 has a greater resilience after the stent is released, The contour morphology at the interface 110 is better restored.

It can be understood that the movable part 122 can also be disposed at other positions of the expansion ring 120 . For example, the movable part 122 can also be disposed near the highest point 123 or the lowest point 124 of the expansion ring 120 . In other words, the two ends of the movable part 122 are respectively located on both sides of the highest point 123 ; or, the two ends of the movable part 122 are respectively located on both sides of the lowest point 124 .

Further, the line between the two ends of the movable part 122 is parallel to the line between the lowest point 124 and the highest point 123 of the expansion ring 120 . The distance between the end point of the movable part 122 close to the highest point 123 and the line between the lowest point 124 and the highest point 123 and the distance between the end point of the movable part 122 close to the lowest point 124 to the lowest point 124 and the highest point 123 The distances between the connecting lines are equal to improve the symmetry of the expansion ring 120 and better ensure the contour shape of the interface 110 .

It can be understood that, in other embodiments, at least one of the non-end wave-shaped rings may have a closed-loop structure, and the expansion ring is located between two adjacent non-end wave-shaped rings. Between rings, such as between two adjacent non-terminal wave-shaped rings that are both open-loop structures, or between two adjacent non-terminal wave-shaped rings that are both closed-loop structures , or between adjacent non-end wave-shaped rings in a closed-loop structure and non-end wave-shaped rings in an open-loop structure. It can also be understood that, in other embodiments, the expandable ring can also be connected to only one non-end wave-shaped ring, and be separated from other non-end wave-shaped rings by a certain distance.

Please refer to FIG. 3 , the movable part 122 is a gap (not shown) provided on the expansion ring 120 , that is, the expansion ring 120 is a non-closed structure. Specifically in this embodiment, the gap is one, and the two ends of the expansion ring 120 are respectively connected to the free ends of the two non-end wave-shaped rings 102, and the distance between the gaps is the distance between the two wave-shaped rings 102. The distance between the two free ends on one side of the expansion ring 120, that is, the free ends of the two non-end wave rings 102 connected on one side of the expansion ring 120, and the two non-end wave rings on the other side The two free ends of the bar 102 are disconnected to form the movable part 122 .

Referring to FIG. 4 , in one embodiment, there are two notches, and the two notches cut the expansion ring 120 into two expansion parts 121 arranged along the longitudinal central axis of the tubular body 100 . Two ends of each expansion portion 121 are respectively connected to two corresponding free ends of one non-end wave-shaped ring 102 . For example, two opposite semi-ellipse structures are provided on two adjacent non-end wave-shaped rings 102 to form the expansion part 121 , and there is a certain interval between the two semi-ellipse structures to form the movable part 122 . Preferably, the distance D between the two ends of the notch of the expansion ring 120 along the longitudinal center axis of the tubular body 100 is not greater than the distance D between the highest point 123 and the lowest point 124 of the expansion ring 120 along the longitudinal center axis of the tubular body 100 0.15 times the length L, ie, D≤0.15L. This is because, if D is greater than 0.15L, the area without metal support near the interface 110 of the first film 103 is large, so that the first film 103 is likely to form wrinkles at the interface 110, thereby affecting the flow of blood.

It can be understood that the expansion portion 121 may be a part of the non-end wave-shaped ring 102 , that is, the expansion portion 121 and the non-end wave-shaped ring 102 are integrally formed. In other words, the expansion ring 120 can be obtained by changing the waveform at the interface 110 on the non-end wave-shaped ring 102 to match the contour of the interface 110, so that no other metal rings need to be added, and only the existing non-end is changed. The waveform structure of the inner wave ring 102 at the interface 110 can maintain the contour shape of the interface 110, thereby ensuring that the blood flow smoothly flows from the tubular body 100 into the side branch 200 through the interface 110, so that the blood flow of the side branch 200 is smooth. , Adequate, and easy guidewire access.

Please refer to FIG. 5. In one embodiment, the expansion part 121 is an open-loop structure, and the two opposite ends of the expansion part 121 first approach each other and then extend away from each other to form an overlapping area (not shown in the figure). The overlapping area forms the movable portion 122, as shown by the dotted line area in FIG. 5 . For example, a metal wire with a biocompatible material is used to form an expansion ring 120 that conforms to the shape of the interface 110, and the two ends overlap, and the ends of the two metal wires in the overlapping area are in a free state. When loaded into the conveyor, the two free ends of the interface 110 are movable under the condition of being squeezed, so that the structure at the interface 110 has a greater amount of compression, and the resistance encountered when loaded into the conveyor is small and the bracket 10 is released There is also less resistance.

In this embodiment, the expansion ring 120 is located at the opening of the non-end wave-shaped ring 102 and has a certain distance from the free end of the non-end wave-shaped ring 102 . Of course, in other embodiments, the expandable ring 120 can also be connected to the free end of the non-end wave-shaped ring 102 .

It should be noted that, in order to avoid scratching the blood vessels, the expansion ring 120 should try to avoid forming sharper parts. Specifically, the end 1221 of the movable part 122 is in a smooth shape, and the smooth structure can be roughly in the shape of a circle or an ellipse. , any curved shape, etc., for example, the end 1221 of the movable part 122 may be roughly in the shape of a ring (see FIG. 6 ).

Please refer to FIG. 7 , the expansion ring 120 is a closed structure, the movable part 122 is a wave segment disposed on the expansion ring 120 , and the wave segment includes several waves. Further, the number of the waveform segments is two, and the two waveform segments are arranged symmetrically. Further, the waveform is at least one of M-shaped wave, Z-shaped wave or sine wave.

In one of the embodiments, the interface 110 is made of a closed biocompatible material, which can be formed by weaving filaments or cutting tubes and shaping them. The expansion ring 120 is generally elliptical, and there is a waveform section on both sides of the long axis. The waveform section includes several waveforms, and the waveform is a regular Z-shaped wave. After the stent is released in the body, the elastic effect of the wave section at the expansion ring 120 can fully self-expand and restore the shape, so as to ensure the contour shape of the interface 110 .

It can be understood that the waveform may also include a combination of various waves, for example, a combination of an M-shaped wave and a sine wave. Of course, the waveform segment can also be a helical structure.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

The above-mentioned embodiments only express several implementation modes of the utility model, and the description thereof is relatively specific and detailed, but it should not be understood as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the scope of protection of the utility model patent should be based on the appended claims.

Claims (15)

1. A bifurcated covered stent comprising a tubular main body and side branches communicating with the tubular main body, the tubular main body comprising a first bare stent and a first film covering the first bare stent, the The first bare stent includes at least one non-end wave-shaped ring, the side branch includes a second covering, and the second covering is connected to the first covering, wherein the first covering The interface between the membrane and the second membrane is provided with an expansion ring distributed along the periphery of the interface, and the expansion ring is at least partially located on the circumferential surface of the tubular body provided with the non-end wave-shaped ring . 2. The bifurcated stent-graft according to claim 1, wherein the first bare stent further comprises a proximal wave ring and a distal wave ring, and the at least one non-end wave A ring is disposed between the proximal wave-shaped ring and the distal wave-shaped ring, the non-end wave-shaped ring is a split ring, and the expansion ring is at least partially located at the non-end The opening of the wave ring. 3. The bifurcated stent graft according to claim 2, wherein the expansion ring is connected to the free end of the non-end wave-shaped ring. 4. The bifurcated stent graft according to claim 2, wherein the number of the non-end wave-shaped rings is at least two, and the expansion ring and at least two of the non-end portions All free ends of the wavy rings are connected. 5. The bifurcated stent-graft according to claim 2, wherein the expansion ring comprises an expansion part formed by a metal wire around the periphery of the interface and a movable part connected with the expansion part, the The expansion portion is located at least partially on the circumferential surface of the non-end wave-shaped ring. 6. The bifurcated stent-graft according to claim 5, wherein the expansion ring has a highest point near the proximal waveform ring and a lowest point near the distal waveform ring , the movable part is located on one side of the line connecting the lowest point and the highest point. 7. The bifurcated stent graft according to claim 6, characterized in that, the line between the two ends of the movable part and the line between the lowest point and the highest point of the expansion ring are lines parallel. 8. The bifurcated stent graft according to any one of claims 6-7, wherein the movable part is a notch provided on the expansion ring. 9. The bifurcated stent graft according to claim 8, wherein there are two notches, and the two notches cut the expansion ring into two along the longitudinal central axis of the tubular body. The expansion parts are arranged in the same direction, and the two ends of each expansion part are respectively connected with two corresponding free ends of one of the non-end wave-shaped rings. 10. The bifurcated stent-graft according to any one of claims 6 to 7, wherein the expansion part is an open-loop structure, and the two opposite ends of the expansion part first approach each other and then close to each other. Extending away forms an overlapping area, which forms the movable part. 11. The bifurcated stent-graft according to claim 10, wherein the end of the movable part is round and smooth. 12. The bifurcated stent-graft according to any one of claims 6-7, wherein the movable part is a wave section provided on the expansion ring, and the wave section includes several waves. 13. The bifurcated stent-graft according to claim 12, wherein the number of the wave segments is two, and the two wave segments are arranged symmetrically. 14. The bifurcated stent-graft according to claim 12, wherein the waveform is at least one of an M-shaped wave, a Z-shaped wave or a sine wave. 15. The bifurcated stent-graft according to claim 1, wherein the angle between the longitudinal central axis of the tubular body and the longitudinal central axis of the side branch is an acute angle, and the expansion ring is Oval.