Stent graft

Abstract

The invention relates to a stent graft which comprises a sealing stent, an anchoring stent and a connecting stent, and the sealing stent comprises a supporting framework and a sealing film arranged on the supporting stent; the anchoring support is located at the far end of the sealing support, an axial distance is formed between the anchoring support and the sealing support, and the radial supporting force of the anchoring support is larger than that of the sealing support. The connecting support comprises a middle section, one end of the middle section is connected with the sealing support, the other end of the middle section is connected with the anchoring support, and the middle section comprises a rod-shaped structure or a filiform structure extending between the near-end end face of the sealing support and the far-end end face of the anchoring support. The minimum axial distance between the near end of the rod-shaped structure or the wire-shaped structure and the near end of the anchoring support is larger than 25 mm. After the stent graft disclosed by the invention is implanted, the displacement risk is relatively low, no new lesion is caused to an implanted part, and the physiological functions of other parts are not influenced.

Description

Technical Field

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

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

[0003] Ascending aortic aneurysm and ascending aortic dissection are common cardiovascular diseases. By minimally invasive interventional means, a covered stent is implanted into the diseased blood vessel, so that the covered stent implanted into the ascending aorta isolates the aneurysm cavity and dissection, and can prevent blood flow from entering the aneurysm cavity and dissection, thereby achieving a therapeutic effect.

[0004] Since the blood flow velocity ejected from the left ventricle is relatively high, and the shape of the ascending aorta is arc-shaped, the large curvature side of the covered stent implanted into the ascending aorta is subjected to a greater impact of blood flow. Therefore, the covered stent is prone to shift away from the heart, thus exposing the aneurysm cavity or dissection again.

[0005] To reduce the risk of the covered stent shifting in the ascending aorta, in the prior art, generally, the radial support force of the covered stent is increased, so as to increase the anchoring force of the covered stent in the ascending aorta and thus reduce the risk of the covered stent shifting. However, since the blood vessel wall of the ascending aorta is relatively thin, after increasing the radial support force of the covered stent, it is easy to cause a new dissection at the site where the covered stent is implanted in the ascending aorta.

[0006] In addition, an ideal implant needs to meet the following requirements: after the implant is implanted into the patient's body, it cannot interfere with the physiological functions of other healthy tissues or organs, and cannot cause new lesions. Summary of the Invention

[0007] Based on this, it is necessary to provide a stent-graft that can reduce the risk of shifting after implantation but will not cause new lesions at the implantation site and affect the physiological functions of other parts.

[0008] A stent-graft includes a sealing stent, an anchoring stent, and a connecting stent. The sealing stent includes a support skeleton and a sealing film disposed on the support stent; the anchoring stent is located at the distal end of the sealing stent and has an axial distance from the sealing stent, and the radial support force of the anchoring stent is greater than that of the sealing stent; the connecting stent includes an intermediate section, one end of the intermediate section is connected to the sealing stent, and the other end is connected to the anchoring stent. The intermediate section includes a rod-shaped structure or a filamentous structure extending between the proximal end face of the sealing stent and the distal end face of the anchoring stent, and the minimum axial distance between the proximal end of the rod-shaped structure or the filamentous structure and the proximal end of the anchoring stent is greater than 25 mm.

[0009] When using the above stent-graft, the anchoring stent can be implanted into the left ventricular outflow tract. After the anchoring stent is radially expanded, it is anchored in the left ventricular outflow tract and axially abuts against the aortic valve annulus, and the sealing stent is implanted into the diseased part of the aorta. Since the myocardium at the left ventricular outflow tract is relatively thick, even if it is subjected to a large radial squeezing force, it will not cause lesions. Therefore, an anchoring stent with a large radial supporting force can be used, and the anchoring stent axially abuts against the aortic valve annulus, so that the anchoring stent can be more reliably anchored in the left ventricular outflow tract. Moreover, since the middle section connects the sealing stent and the anchoring stent, even if the radial supporting force of the sealing stent is set to be small, when impacted by blood flow, the sealing stent can be more reliably anchored in the diseased part of the aorta due to the pulling of the middle section. Using a sealing stent with a small radial supporting force is beneficial to avoid the occurrence of a new arterial dissection in the ascending aorta.

[0010] Meanwhile, the middle section includes a rod-shaped structure or a filamentous structure extending between the proximal end face of the sealing stent and the distal end face of the anchoring stent. The minimum axial distance between the proximal end of the rod-shaped structure or the filamentous structure and the proximal end of the anchoring stent is greater than 25 mm. After the stent-graft is implanted, the rod-shaped structure or the filamentous structure can pass through the gap between the aortic valve leaflets without affecting the normal opening and closing of the aortic valve leaflets.

[0011] Therefore, the above stent-graft can reduce the risk of displacement after the sealing stent is implanted, but will not cause new lesions at the implantation site and will not affect the physiological functions of other parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0013] Among them:

[0014] Figure 1 is a schematic structural diagram of a stent-graft in an embodiment;

[0015] Figure 2 is a schematic structural diagram of a connecting stent in an embodiment;

[0016] Figure 3 is a state diagram of the implanted state of the stent-graft in an embodiment;

[0017] Figure 4 is a schematic structural diagram of a partial structure of an anchoring stent in an embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0019] In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the embodiments of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0020] In the description of the embodiments of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a replaceable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium. It can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific situations.

[0021] In the field of interventional medical devices, generally, the end of a medical device implanted into the human body or animal body that is closer to the operator is called the "proximal end", and the end that is farther from the operator is called the "distal end", and the "proximal end" and "distal end" of any component of the medical device are defined based on this principle. The "axial direction" generally refers to the length direction of the medical device when it is being delivered, and the "radial direction" generally refers to the direction of the medical device that is not parallel to its "axial direction", and the "axial direction" and "radial direction" of any component of the medical device are defined based on this principle. The "circumferential direction" refers to the circumferential direction, that is, the direction around the axis of the lumen structure or cylinder.

[0022] Please refer to Figure 1, the present disclosure provides a stent graft 1, comprising a connected sealing stent 10, an anchoring stent 20 and a connecting stent 30. Among them, the sealing stent 10 is used to be implanted into a diseased blood vessel to isolate the blood flowing into the diseased site (such as an aneurysm or an arterial dissection). The radial supporting force of the anchoring stent 20 is greater than that of the sealing stent 10. After the anchoring stent 20 is implanted into the patient's body, it has a higher stability. The anchoring stent 20 is connected to the sealing stent 10 through the connecting stent 30. When blood flows through the stent graft 1, it flows from the anchoring stent 20 to the sealing stent 10. When the sealing stent 10 moves proximally or has a tendency to move proximally, the anchoring stent 20 applies a tensile force to the sealing stent 10 through the connecting stent 30, preventing the sealing stent 10 from shifting along the blood flow direction, thereby increasing the stability of the sealing stent 10 at the implantation site.

[0023] Please refer to Figure 1 and Figure 3 , the sealing stent 10 is located at the proximal end of the stent graft 1 and can be implanted into the diseased aorta to isolate the blood flow entering the diseased site (such as an aneurysm or an arterial dissection). In this embodiment, the sealing stent 10 is used as an example for implanting into the ascending aorta 51 to treat an aortic aneurysm.

[0024] The sealing stent 10 is a tubular structure, and the sealing stent 10 includes a connected sealing membrane 11 and a support framework 12.

[0025] Please refer to Figure 1 , the sealing membrane 11 has sealing performance. When the sealing membrane 11 covers the aortic aneurysm 52, it can prevent blood flow from entering the aneurysm cavity of the aortic aneurysm 52. The material of the sealing membrane 11 can be materials with biocompatibility and certain sealing performance such as polytetrafluoroethylene (PTFE), polyester (PET), etc.

[0026] Please refer to Figure 1, the support framework 12 is connected to the sealing film 11. The support framework 12 can be formed by braiding and shaping braided wires, or can be formed by cutting and shaping hollow pipes, so that the support framework 12 can expand radially by itself or maintain the expanded shape and size after being radially expanded (for example, expanded by a balloon). The braided wires can be nitinol wires, stainless steel wires or other metal wires. The hollow pipes can be metal pipes such as nitinol pipes and stainless steel pipes. The support framework 12 includes a plurality of corrugated rings connected to the sealing film 11. The plurality of corrugated rings are arranged axially. Each corrugated ring can expand radially by itself or maintain the expanded shape and size after being radially expanded, so that the support framework 12 has radial supporting force, thereby enabling the sealing stent 10 to have radial supporting force. The sealing film 11 can be arranged on the inner surface of the support framework 12, or the sealing part 11 only covers the outer surface of the support framework 12. Or, the support framework 12 is embedded inside the sealing film 11, that is, the sealing film 12 covers the outer surface and the inner surface of the support framework 12. When the sealing stent 10 is released in the ascending aorta 51, the sealing film 11 unfolds radially under the radial supporting action of the support framework 12 to cover the diseased part, and can prevent blood flow from entering the aneurysm cavity.

[0027] Please refer to Figure 1 and Figure 3 , the anchoring stent 20 is located at the distal end of the sealing stent 10 and has an axial distance from the sealing stent 10, so that the anchoring stent 20 is located upstream of the blood flow (the direction from the distal end to the proximal end of the stent graft 1 is the forward direction of the blood flow), and can be implanted into the left ventricular outflow tract 61. The anchoring stent 20 can be formed by braiding and shaping braided wires, or can be formed by cutting and shaping hollow pipes, so that the anchoring stent 20 can expand radially by itself. The braided wires can be nitinol wires, stainless steel wires or other metal wires. The hollow pipes can be metal pipes such as nitinol pipes and stainless steel pipes. The anchoring stent 20 includes a main body stent 21. The main body stent 21 includes a plurality of wave rings 211 arranged axially and connected. Each wave ring 211 can expand radially by itself, so that the anchoring stent 20 has radial supporting force. When the anchoring stent 20 is implanted into the left ventricular outflow tract 61, the anchoring stent 20 can be stably anchored in the left ventricular outflow tract 61. Moreover, the radial supporting force of the anchoring stent 20 is greater than the radial supporting force of the sealing stent 10, so that the stability of the anchoring stent 20 at the axial position in the left ventricular outflow tract 61 is higher than the stability of the sealing stent 10 at the axial position in the ascending aorta 51.

[0028] Please refer to Figure 1 , the connecting stent 30 is located between the sealing stent 10 and the anchoring stent 20, and one end of the connecting stent 30 is connected to the sealing stent 10 and the other end is connected to the anchoring stent 20.

[0029] Specifically, please refer to Figure 1 and Figure 2, the connecting bracket 30 includes a proximal segment 31, an intermediate segment 32, and a distal segment 33 that are sequentially distributed and connected from near to far. The proximal end of the proximal segment 31 is connected to the sealing bracket 10, and the distal end of the intermediate segment 32 is connected to the anchoring bracket 20, so that the anchoring bracket 20 can be connected to the sealing bracket 10 through the connecting bracket 30. The proximal end of the intermediate segment 32 is located between the distal end of the sealing bracket 10 and the proximal end of the anchoring bracket 20. The intermediate segment 32 includes a rod-shaped structure or a filamentous structure 321. The rod-shaped structure or the filamentous structure 321 extends between the distal end face of the sealing bracket 10 and the distal end face of the anchoring bracket 20, and the minimum axial distance between the proximal end of the rod-shaped structure or the filamentous structure 321 and the proximal end of the anchoring bracket 20 is 25 mm.

[0030] Please refer to Figures 1 to 3 , after the stent graft 1 is implanted, the anchoring bracket 20 is located in the left ventricular outflow tract 61, and the proximal end of the anchoring bracket 20 abuts against one end of the aortic valve annulus 71 away from the ascending aorta 51. Since the aortic valve annulus 71 protrudes radially inward relative to the left ventricular outflow tract 61, the proximal end of the anchoring bracket 20 abutting against one end of the aortic valve annulus 71 away from the ascending aorta 51 can prevent the anchoring bracket 20 from shifting proximally, and the anchoring bracket 20 is reliably anchored in the left ventricular outflow tract 61. After the anchoring bracket 20 is radially expanded, the outer wall of the anchoring bracket 20 radially abuts against the left ventricular outflow tract 61, and the radial supporting force of the anchoring bracket 20 is relatively large, which can further ensure the stability of the axial position of the anchoring bracket 20 in the left ventricular outflow tract 61 and firmly anchor the anchoring bracket 20 in the left ventricular outflow tract 61. Moreover, since the myocardium at the left ventricular outflow tract 61 is relatively thick, even if it is subjected to a large radial squeezing force, it will not cause lesions. Therefore, after the anchoring bracket 20 is implanted in the left ventricular outflow tract 61, the left ventricular outflow tract 61 will not be damaged due to the large radial supporting force of the anchoring bracket 20.

[0031] Please refer to Figures 1 to 3 , since the proximal end of the intermediate segment 32 is located between the distal end of the sealing bracket 10 and the proximal end of the anchoring bracket 20, and the minimum axial distance between the proximal end of the rod-shaped structure or the filamentous structure 321 and the proximal end of the anchoring bracket 20 is greater than 25 mm, and the length range of the human aortic valve leaf 72 is [15 mm, 25 mm], that is, when the aortic valve leaf 72 is in the open state, the axial distance between the proximal end of the aortic valve leaf 72 and the aortic valve annulus 71 ranges from [15 mm, 25 mm]. That is to say, the distal end of the intermediate segment 32 extends beyond the position of the valve leaf 72 in the direction from distal to proximal and is located proximal to the valve leaf 72, so that the rod-shaped structure or the filamentous structure 321 passes through the gap of the aortic valve leaf 72 without affecting the normal opening and closing of the aortic valve leaf 72.

[0032] Please refer to Figures 1 to 3, the sealing stent 10 is located in the ascending aorta 51. When the sealing stent 10 is impacted by the blood flow ejected from the left ventricle, and the radial supporting force of the sealing stent 10 itself is not sufficient to resist the impact force of the blood flow and shifts proximally or has a tendency to shift proximally, due to the large radial supporting force of the anchoring stent 20 and high stability in the axial position within the left ventricular outflow tract 61, and the sealing stent 10 is connected to the anchoring stent 20 through the connecting stent 30, the sealing stent 10 will be subjected to a distal pulling force from the anchoring stent 20, thereby increasing the stability of the axial position of the sealing stent 10 within the ascending aorta 51 and preventing the sealing stent 10 from shifting. Therefore, in this embodiment, the stent graft 1 does not need to increase the radial supporting force of the sealing stent 10 and can also prevent the sealing stent 10 from shifting. Without increasing the radial supporting force of the sealing stent 10, the occurrence of a new arterial dissection within the ascending aorta 51 caused by the sealing stent 10 can be avoided. Thus, the stent graft 1 of this embodiment can reduce the risk of displacement of the sealing stent 10 after implantation, will not cause new lesions at the implantation site, and will not affect the physiological functions of other parts.

[0033] In one embodiment, moreover, the rod diameter of the rod-shaped structure ranges from 2 mm to 3 mm, or the wire diameter of the filamentous structure ranges from 2 to 3 mm, such that the rod-shaped structure or the filamentous structure 321 only occupies a relatively small part of the radial space of the aortic valve annulus 71, thereby ensuring that the gap between the aortic valve annulus 71 and the intermediate section 32 is large enough, and the blood flow rate flowing out through the gap between the aortic valve annulus 71 and the intermediate section 32 per unit time is sufficient to meet the needs of the human body. And, due to the small outer diameter of the rod-shaped structure or the filamentous structure 321, the rod-shaped structure or the filamentous structure 321 will not radially squeeze the valve leaflets 72 to a large extent, thereby avoiding the situation where the aortic valve leaflets 72 cannot open and close normally, resulting in the inability to function as a "one-way valve".

[0034] In other embodiments, the proximal section 31 and the distal section 33 can also be omitted. After omitting the proximal section 31 and the distal section 33, the proximal end of the intermediate section 32 is directly connected to the sealing stent 10, and the distal end of the intermediate section 32 is directly connected to the anchoring stent 20. For example, the proximal end of the rod-shaped structure or the filamentous structure 321 is directly connected to the sealing stent 10, and the distal end is directly connected to the anchoring stent 20.

[0035] Please refer to Figure 1 and Figure 3 , in one embodiment, the rod-shaped structure or the filamentous structure 321 is a flexible structure. When the rod-shaped structure or the filamentous structure 321 is subjected to an axial tensile force, its length remains unchanged, so that while the rod-shaped structure or the filamentous structure 321 has flexibility, it can also transmit the pulling force. In Figure 1In the illustrated embodiment, the rod-shaped structure or filamentous structure 321 has a flexible rope capable of transmitting a pulling force. Generally speaking, there is a certain angle between the ascending aorta 51 and the left ventricular outflow tract 61. During the implantation of the sealing stent 10 and the anchoring stent 20, since the rod-shaped structure or filamentous structure 321 is flexible, the anchoring stent 20 and the sealing stent 10 can deflect relative to each other during implantation to adapt to the physiological structure of their respective implantation sites, so that the implanted anchoring stent 20 and sealing stent 10 form a certain included angle. Moreover, since the length of the rod-shaped structure or filamentous structure 321 remains unchanged when subjected to an axial tensile force, when the sealing stent 10 moves proximally or has a tendency to move proximally, the anchoring stent 20 can transmit a pulling force to the sealing stent through the rod-shaped structure or filamentous structure 321, so that the sealing stent 10 can be stably anchored in the ascending aorta.

[0036] Please refer to Figure 1 and Figure 4 , the anchoring stent 20 further includes a plurality of stoppers 22. One end of each stopper 22 is connected to the proximal end of the main body stent 21, and the other end bends and extends towards the direction close to the central axis of the main body stent 21 to form a resisting portion. After the anchoring stent 20 is implanted, the resisting portion abuts against the aortic valve annulus 71, which can increase the contact area between the proximal end of the anchoring stent 20 and the aortic valve annulus 71, thereby increasing the reliability of the abutting connection between the anchoring stent 20 and the aortic valve annulus 71, and further increasing the stability of the axial position of the anchoring stent 20 in the left ventricular outflow tract 61, which can indirectly improve the stability of the axial position of the sealing stent 10 in the ascending aorta 51. Moreover, the stopper 22 of the resisting portion abuts against the aortic valve annulus 71, which can prevent the peak of the wave loop 211 (i.e., the sharp corner portion of the wave loop 211) at the proximal end of the main body stent 21 from piercing into the aortic valve annulus 71 and causing damage to the aortic valve annulus 71. In one embodiment, the stopper 22 is connected to the peak of the wave loop 211 at the proximal end of the main body stent 21.

[0037] Please refer to Figure 1 and Figure 3 , in one embodiment, the middle section 32 further includes a buffer portion 322 and a rigid bearing portion 323. The proximal end of the bearing portion 323 is connected to the rod-shaped structure or filamentous structure 321, and the distal end is connected to the anchoring stent 20. The buffer portion 322 is provided on the bearing portion 323.

[0038] When the aortic valve leaflets 72 are in the closed state, the axial distance between the coaptation edge and the aortic valve annulus 71 ranges from [5 mm, 10 mm], and the length of the human aortic valve leaflets 72 ranges from [15 mm, 25 mm]. Therefore, when the aortic valve leaflets 72 are closed, they contact the buffer portion 322 of the middle segment 32. The buffer portion 322 is sleeved on the bearing portion 323, which can increase the contact area of the contact portion between the middle segment 32 and the aortic valve leaflets 72, thereby preventing the aortic valve leaflets 72 from being damaged when they flap against the middle segment 32.

[0039] The buffer portion 322 is a flexible structure. After being subjected to the radial extrusion force exerted by the aortic valve leaflets 72, the buffer portion 322 can contract inward along the radial direction, thereby absorbing a part of the acting force and avoiding damage to the aortic valve leaflets 72 when they flap against the middle segment 32. In one embodiment, the buffer portion 322 includes a polyester cloth, and the polyester cloth is wound in multiple turns to form a columnar structure, and there is a certain gap between the multiple turns of polyester cloth.

[0040] In other embodiments, the buffer portion 322 can also be sleeved on a rod-shaped structure or a filamentous structure 321. When the aortic valve leaflets 72 flap against the middle segment 32, the buffer portion 322 can absorb a part of the acting force to play a buffering role, thereby protecting the aortic valve leaflets 72. Moreover, the outer diameter of the buffer portion 322 is larger than the outer diameter of the rod-shaped structure or the filamentous structure 321, which can avoid cutting the aortic valve leaflets 72 due to the too small outer diameter of the buffer portion 322, so as to avoid damaging the aortic valve leaflets 72.

[0041] Please refer to Figure 1 and Figure 2 In one embodiment, the proximal end of the proximal segment 31 is connected to the distal end of the sealing stent 10. That is to say, the connection point between the proximal segment 31 and the sealing stent 10 is located at the distal end of the sealing stent 10. When the connecting stent 30 exerts a pulling force on the sealing stent 10, the acting point is located at the distal end of the sealing stent 10. The sealing stent 10 is subjected to the pulling force from the connection point to the proximal end of the sealing stent 10 and will not shift, that is, the part within the entire length interval of the sealing stent 10 will not shift and will not undergo axial shortening, which is beneficial to increasing the stability of the axial position of the sealing stent 10 in the ascending aorta 51. In one embodiment, the proximal end of the proximal segment 31 and the sealing stent 10 can be connected by welding, hooking, or suture stitching, etc. In other embodiments, the proximal segment 31 extends into the sealing stent 10 and can also be connected to the sealing stent 10. The proximal segment 31 can also transmit the pulling force exerted by the anchoring stent 20 on the sealing stent 10, thereby avoiding or reducing the distal shift of the sealing stent 10.

[0042] Please refer to Figure 1 and Figure 2, in one embodiment, the proximal segment 31 includes a plurality of proximal branches 311, and the number of the proximal branches 311 can be two, three or more. The material of the proximal branches 311 can be nitinol alloy. The proximal ends of the plurality of proximal branches 311 are connected to the sealing stent 10, and the distal ends of the plurality of proximal branches 311 extend obliquely towards the central axis of the sealing stent 10, such that the distance between each proximal branch 311 and the central axis of the sealing stent 10 gradually decreases in the direction from the proximal end to the distal end, so that the proximal segment 31 is generally a tapered hollow structure with a smaller distal end and a larger proximal end. When blood flow passes through the proximal segment 31, the impact force received by the proximal segment 31 can be reduced, thereby reducing the force transmitted from the proximal segment 31 to the sealing stent 10 in the direction from the distal end to the proximal end, and further improving the stability of the axial position of the sealing stent 10 in the ascending aorta 51. Moreover, the material of the proximal branches 311 can be a shape memory material such as nitinol alloy, and the proximal segment 31 is generally a tapered structure with a smaller distal end and a larger proximal end, so that the proximal segment 31 can be radially compressed and self-expanded. The distal ends of the plurality of proximal branches 311 are connected to the intermediate segment 32 after intersecting. In other embodiments, the distal ends of the plurality of proximal branches 311 do not intersect, as long as the distal ends of the proximal branches 311 are connected to the intermediate segment 32 and can transmit the pulling force exerted by the anchoring stent 20 on the sealing stent 10. In this embodiment, the distal ends of the plurality of proximal branches 311 are connected to a connector 312 and are connected to the intermediate segment 32 through the connector 312.

[0043] Please refer to Figure 1 , in one embodiment, one end of the plurality of proximal branches 311 connected to the sealing stent 10 is circumferentially spaced, so that adjacent proximal branches 311 form pores 313 at positions other than the proximal ends where they are connected to each other. When blood flow passes through the proximal segment 31, the pores 313 formed by adjacent proximal branches 311 can allow blood flow to pass through, which can reduce the impact force of the blood flow received by the proximal segment 31, thereby avoiding a relatively large force pointing towards the proximal end transmitted from the proximal segment 31 to the sealing stent 10, and thus reducing the risk of the sealing stent 10 shifting towards the proximal end. Moreover, the proximal ends of the proximal segment 31 are evenly distributed in the circumferential direction, so that the connection points between the proximal segment 31 and the sealing stent 10 are evenly distributed in the axial direction. Thus, the pulling force received by the proximal end of the sealing stent 10 is more uniform, and the stability of the position of the sealing stent 10 can be improved.

[0044] Please refer to Figure 1 and Figure 3, in one embodiment, the distal segment 33 extends into the anchoring bracket 20. The distal segment 33 includes a plurality of rigid and connected distal branches 331. Each distal branch 331 is connected to the bearing portion 323, and the distal end is a free end. The distal branches 331 are radially spaced apart. The distal ends of the distal branches 323 abut against and are fixedly connected to the inner wall of the anchoring bracket. Since both the bearing portion 323 and the distal segment 33 have a certain rigidity, under the scouring of blood flow, the positions of the distal segment 33 and the bearing portion 323 can still remain stable without large swings, so that the position of the buffer portion 322 located on the bearing portion 323 is relatively stable, ensuring that each time the aortic valve leaf 72 closes, the buffer portion 322 can contact the aortic valve leaf 72, thereby ensuring that the reaction force received by the aortic valve leaf 72 when hitting the middle segment 32 is reduced, and the aortic valve leaf 72 can be protected.

[0045] Please refer to FIGS. 1 and Figure 2 , in Figure 1 and Figure 2 In the embodiment shown in FIGS. 1 and

[0046] Please refer to FIGS. 1 and Figure 2 , the proximal end of each distal branch 331 extends obliquely towards the central axis of the anchoring bracket 20, so that the distance between each distal branch 331 and the central axis of the sealing bracket 10 gradually increases in the direction from the distal end to the proximal end. As a result, the distal segment 33 is generally a conical hollow structure with a larger distal end and a smaller proximal end. When blood flow passes through the distal segment 33, the impact force received by the distal segment 33 can be reduced, the stability of the position of the distal segment 33 can be increased, thereby reducing the force transmitted from the distal segment 33 to the bearing portion 323 and the sealing bracket 10 in the distal-to-proximal direction, and further improving the axial position stability of the bearing portion 323 and the sealing bracket 10. Moreover, the material of the distal branch 331 can be a shape-memory material such as nitinol. The distal segment 33 is generally a conical structure with a larger distal end and a smaller proximal end, so that the distal segment 33 can be radially compressed and self-expanded. The proximal ends of the three distal branches 331 intersect and are connected to the bearing portion 323. In other embodiments, the proximal ends of the three distal branches 331 do not intersect, as long as the proximal ends of the three distal branches 331 are connected to the bearing portion 323 and can transmit the pulling force exerted by the anchoring bracket 20 on the sealing bracket 10 and the middle segment 32.

[0047] Please refer to Figure 2 , in one embodiment, pores 332 are formed at positions of any two adjacent distal branches 331 among the three distal branches 331 except at the proximal ends where they are connected to each other. When blood flow passes through the distal section 33, the two adjacent distal branches 331 form pores 332 through which the blood flow can pass, which can reduce the impact force of the blood flow on the distal section 33, thereby avoiding a relatively large proximal-directed force transmitted from the distal section 33 to the sealing stent 10 and the intermediate section 32, and thus reducing the risk of proximal displacement of the sealing stent 10 and the intermediate section 32.

[0048] 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 embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0049] The above-disclosed are only the preferred embodiments of the present invention. Of course, the scope of the rights of the present invention cannot be limited thereby. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A stent graft, characterized in that, Comprising: A sealing bracket, including a support skeleton and a sealing film disposed on the support bracket; An anchoring bracket, located at the distal end of the sealing bracket and having an axial spacing from the sealing bracket, and the radial supporting force of the anchoring bracket is greater than that of the sealing bracket; A connecting bracket, the connecting bracket includes an intermediate section, one end of the intermediate section is connected to the sealing bracket, and the other end is connected to the anchoring bracket. The intermediate section includes a rod-shaped structure or a filamentous structure extending between the proximal end face of the sealing bracket and the distal end face of the anchoring bracket, and the minimum axial spacing between the proximal end of the rod-shaped structure or the filamentous structure and the proximal end of the anchoring bracket is greater than 25 mm.

2. The stent graft according to claim 1, wherein The connecting bracket further includes a proximal section and a distal section. The two ends of the rod-shaped structure or the filamentous structure are respectively connected to the proximal section and the distal section. One end of the proximal section away from the rod-shaped structure or the filamentous structure is connected to the distal end of the sealing bracket or the proximal section extends into the sealing bracket and is connected to the sealing bracket, and the distal section extends into the anchoring bracket and is connected to the anchoring bracket.

3. The stent graft according to claim 2, characterized in that, The proximal section includes a plurality of proximal branches. The proximal end of each proximal branch is connected to the distal end of the sealing bracket. The distal end of each proximal branch inclines towards the central axis of the sealing bracket and is connected to the intermediate section, so that the distance between each proximal branch and the central axis of the sealing bracket gradually decreases in the direction from proximal to distal, forming a tapered hollow structure with a large proximal end and a small distal end.

4. The stent graft according to claim 1, characterized in that, The anchoring bracket includes a main body bracket and a plurality of stoppers. One end of each stopper is connected to the proximal end of the main body bracket, and the other end bends and extends towards the central axis of the main body bracket to form an abutting portion.

5. The stent graft according to claim 1, characterized in that, The rod-shaped structure or the filamentous structure is a flexible structure.

6. The stent graft according to claim 1, wherein The intermediate section further includes a buffer portion. The buffer portion is sleeved on the rod-shaped structure or the filamentous structure, and the buffer portion can radially contract when subjected to a radial compression force.

7. The stent graft according to claim 1, characterized in that, The intermediate section further includes a buffer portion and a rigid bearing portion. The proximal end of the bearing portion is connected to the rod-shaped structure or the filamentous structure, and the distal end is connected to the anchoring bracket. The buffer portion is sleeved on the bearing portion, and the buffer portion can radially contract when subjected to a radial compression force.

8. The stent graft according to claim 6 or 7, characterized in that, The buffer portion is a flexible structure.

9. The stent graft according to claim 1, wherein, The rod diameter of the rod-shaped structure ranges from 2 to 3 mm; alternatively, the wire diameter of the filamentous structure ranges from 2 to 3 mm.

10. The stent graft according to claim 2, wherein The distal section includes a plurality of distal branches. The proximal end of each distal branch is connected to the rod-shaped structure or the filamentous structure, and the distal end is a free end. The plurality of distal branches are separated radially. The distal section extends into the anchoring bracket, and the distal ends of the plurality of distal branches abut against the inner wall of the anchoring bracket and are fixedly connected.

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