Stent graft and delivery system

Abstract

The present invention provides a coated stent and a delivery system, comprising a main stent with a tubular body, wherein the main stent comprises a proximal segment and a distal segment in sequence along the axial direction, the distal segment comprises a first branch and a second branch, the lumen of the first branch and the lumen of the second branch are both connected to the lumen of the proximal segment, and a double-branch implantation method of implanting a small stent is adopted, so that the types of blood vessels that the coated stent can adapt to are increased, and the adaptability is strong. Furthermore, the first branch and the second branch are spirally wound around each other and then fixedly arranged; so that the coated stent can increase the anchoring length of the implanted small stent under the same axial length, thereby increasing the stability after connection.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a stent graft and a delivery system. Background Art

[0002] The iliac arteries include the common iliac arteries, external iliac arteries, and internal iliac arteries; in the treatment of iliac aneurysm diseases, the existing technology can use intravascular therapy to implant an iliac artery bifurcation stent and an internal iliac covered stent to reconstruct the arterial blood vessels. The iliac artery bifurcation stent usually has two branch channels, which are used to reconstruct the internal iliac artery and the external iliac artery respectively. Usually, there is a lumen at the proximal and distal ends of the stent, and the middle section needs to be provided with a branch lumen of sufficient length for connecting to the internal iliac blood vessels. In order to adapt to the patient's vascular anatomy, the smaller the space occupied by the stent in the middle section, the better. The existing iliac artery bifurcation stent has a low space utilization rate. In order to ensure that the branch lumen and the internal iliac stent have sufficient connection length, it is often necessary to design the lumen of the branch channel to be relatively long, which places high requirements on the morphology of the patient's aneurysm cavity and is not conducive to expanding the scope of application of the device. Summary of the Invention

[0003] Based on this, it is necessary to provide a new covered stent that can cooperate with the implantation of multi-branch stents to adapt to various diseased vascular morphologies without changing the original design size of the covered stent, while increasing the anchoring length of the branch stent in the covered stent to increase the stability of the connection.

[0004] A coated stent comprises a main stent having a tubular body, wherein the main stent comprises a proximal segment and a distal segment in sequence along the axial direction, wherein the distal segment comprises a first branch and a second branch, wherein the lumen of the first branch and the lumen of the second branch are both connected to the lumen of the proximal segment, and the first branch and the second branch are spirally wound around each other and fixedly arranged.

[0005] In one embodiment, the first branch and / or the second branch includes a proximal portion close to the proximal end and a distal portion close to the distal end along the axial direction, and a helical angle of the proximal portion is greater than or equal to a helical angle of the distal portion.

[0006] In one embodiment, at least the portion of the proximal portion connected to the proximal segment includes a proximal straight tube segment, and the central axis of the proximal straight tube segment is parallel to the central axis of the proximal segment.

[0007] In one embodiment, the first branch and / or the second branch each include a plurality of first wave coils arranged along the axial direction, and a plurality of adjacent first wave coils are spaced apart from each other and / or hung together.

[0008] In one embodiment, the end of the first branch away from the proximal segment includes a first distal tube segment, the end of the second branch away from the proximal segment includes a second distal tube segment, and the central axis of the first distal tube segment and the central axis of the second distal tube segment have an angle α between them, and the range of the angle α is 0°~180°.

[0009] In one embodiment, the first distal tube segment includes a first distal straight tube segment, and the second distal tube segment includes a second distal straight tube segment. The central axes of the first distal straight tube segment and the second distal straight tube segment are both perpendicular to the central axis of the proximal segment, and there is an angle β between the central axes of the first distal straight tube segment and the second distal straight tube segment, and the range of the β angle is 180°.

[0010] In one embodiment, the distal segment includes an outer covering layer, the outer covering layer is coated on outer surfaces of the first branch and the second branch, and the surface roughness of the outer covering layer is greater than or equal to the surface roughness of the proximal segment.

[0011] In one embodiment, the outer surface of the first branch and the outer surface of the second branch are fixedly connected at a position where they at least partially contact each other, and / or the outer surface of the first branch and the outer surface of the second branch are both at least partially fixedly connected to the outer covering layer.

[0012] In one embodiment, a diameter of the first branch is greater than or equal to a diameter of the second branch.

[0013] In one embodiment, the first branch and / or the second branch comprises a proximal branch port located at the proximal end and a distal branch port located at the distal end, and the proximal branch port and the distal branch port are respectively located on the same side or opposite sides of the distal segment in the circumferential direction.

[0014] A delivery system includes the above-mentioned coated stent and a delivery device, wherein the delivery device includes a delivery handle, a sheath and a push rod, wherein the delivery handle is movably connected to the sheath and the push rod respectively, and the sheath can move axially relative to the push rod; a hook is provided at the proximal end of the push rod, and the proximal end of the coated stent includes a hook portion, and the hook is detachably connected to the hook portion from the outside of the coated stent.

[0015] The beneficial effects of the present invention are: compared with the prior art, the present invention provides a coated stent and a delivery system, including a main stent with a tubular body, the main stent including a proximal segment and a distal segment in sequence along the axial direction, the distal segment including a first branch and a second branch, the lumen of the first branch and the lumen of the second branch are both connected to the lumen of the proximal segment, and the double-branch implantation method of the small stent is adopted, which can increase the types of blood vessels that the coated stent can adapt to, and has strong adaptability. Furthermore, the first branch and the second branch are spirally wound around each other and then fixed; so that the coated stent can increase the anchoring length of the implanted small stent at the same axial length, thereby increasing the stability after connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the structure of the coated stent in Example 1 of the present invention.

[0017] Figure 2 This is a schematic diagram of the mutual hooking structure of the first wave coils in Example 1 of the present invention.

[0018] Figure 3 This is a schematic diagram of the structure in which the outer surfaces of the first branch and the second branch are fixed to each other in the first embodiment of the present invention.

[0019] Figure 4 This is a schematic diagram of the structure in which the first branch and the second branch are fixed to the outer covering layer in the first embodiment of the present invention.

[0020] Figure 5 Schematic diagram of the overall structure of the conveyor in Example 1 of the present invention.

[0021] Figure 6 This is a structural diagram of a hook member in Embodiment 1 of the present invention.

[0022] Figure 7 Schematic diagram of the structure with different helical angles at the proximal and distal ends in embodiment 2 of the present invention.

[0023] Figure 8 This is a schematic diagram of the structure of a straight pipe section provided at the proximal end portion in the second embodiment of the present invention.

[0024] Figure 9 This is a schematic diagram of the structure in which the first distal tube segment and the second distal tube segment have an included angle α in embodiment three of the present invention.

[0025] Figure 10 This is a schematic diagram of the 180° structure of the first distal tube segment and the second distal tube segment in embodiment 3 of the present invention.

[0026] Figure 11 This is a structural diagram of the third embodiment of the present invention, in which the first distal tube segment and the second distal tube segment of the covered stent are implanted into the aorta at an angle of 180 degrees.

[0027] Figure 12 This is a schematic structural diagram of the branch proximal port and the branch distal port located on the same side of the distal end segment in the circumferential direction in the fourth embodiment of the present invention.

[0028] Figure 13 This is a structural schematic diagram of the stent graft disposed in the iliac bifurcation vessel when the proximal branch port and the distal branch port are located on the same side of the distal segment in the circumferential direction in the fourth embodiment of the present invention.

[0029] Figure 14 This is a structural diagram of the fourth embodiment of the present invention in which the proximal branch port and the distal branch port are located on different sides after being wound.

[0030] Figure 15 This is a structural schematic diagram of the stent graft disposed in the iliac bifurcation vessel when the proximal branch port and the distal branch port are located on different sides after winding in the fourth embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to better understand the concept of the present application, the following detailed description of the implementation methods of the present application is given in conjunction with the accompanying drawings. The following specific embodiments are only some embodiments of the present application and are not limitations of the present application.

[0032] For ease of description, spatially relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figures, such as "inside," "outside," "inside," "outside," "below," "beneath," "above," and the like. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is flipped, an element described as "below" or "beneath" another element or feature would then be oriented as "above" or "above" the other element or feature. Thus, the example term "below" can include both above and below orientations. The device may be oriented otherwise (rotated 90 degrees or in other orientations) and the spatially relative descriptors used herein should be interpreted accordingly.

[0033] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0034] To more clearly describe the structure of this application, the terms "proximal" and "distal" are defined here as commonly used in the field of interventional medicine. Specifically, "distal" refers to the end of a blood vessel away from the heart, and "proximal" refers to the end of a blood vessel closer to the heart; "axial" refers to its length, and "radial" refers to the direction perpendicular to the "axial" direction; "upper end" and "lower end" are two ends that are relatively far apart. When one end is defined as the "upper end," the other end that is farther away is the "lower end."

[0035] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

[0036] Example 1:

[0037] This application provides a stent graft 100, see Figure 1, used for implantation in a bifurcated blood vessel of the human body for treatment, the bifurcated blood vessel includes a main blood vessel and at least two branch blood vessels branching out from the main blood vessel, wherein the covered stent 100 includes a main stent with a tubular body, the main stent includes a proximal segment 1 and a distal segment 2 in sequence along the axial direction, usually, the proximal segment 1 is arranged in the main blood vessel of the bifurcated blood vessel, and the distal segment 2 is located at the intersection of the main blood vessel and the branch blood vessel, the distal segment 2 includes a first branch 3 and a second branch 4, wherein the first branch 3 and the second branch 4 are both stent structures with lumens, the lumens of the first branch 3 and the second branch 4 are both connected to the lumens of the proximal segment 1, here, the first branch 3 and the second branch 4 are used to receive blood from the proximal segment 1 of the covered stent 100 And it is diverted into two branches at the distal section 2. The first branch 3 and the second branch 4 are used to implant a small stent respectively during the implantation operation, and the blood flowing to the first branch 3 and the second branch 4 is drained to the other two branch blood vessels through the two small stents. Here, the setting of the first branch 3 and the second branch 4 can achieve better blood diversion and small stent anchoring effect. At the same time, the first branch 3 and the second branch 4 are used to drain to the branch blood vessels after the small stent is implanted, so that the coated stent 100 provided in the present application can adapt to more blood vessel types, and branch small stents of different specifications and shapes are implanted according to different blood vessel morphologies and types, thereby greatly improving the adaptability of the coated stent 100 of the present application. Specifically, in this embodiment, in order to make the small stent have better anchoring effect and long-term stability when implanted in the first branch 3 and the second branch 4, the second branch 4 is spirally wound with each other and then fixed. In this way, when the straight-line distance between the proximal port and the distal port is the same, the first branch 3 and the second branch 4 spirally wound in the middle have a longer axial extension length compared to the traditional straight-cylinder stent, thereby providing a longer anchoring length, so that the user can use a small stent with a longer anchoring length for implantation to increase the anchoring length and contact area between the small stent and the first branch 3 and the second branch 4, thereby being able to improve the adaptable blood vessel type of the coated stent 100 while also providing a better and more stable anchoring effect.

[0038] In this example, see Figure 2 and Figure 3The first branch 3 or the second branch 2 may include a first surface coating 313 and a first wave ring 312. The provision of the first wave ring 312 may enable the first branch 3 or the second branch 2 to have better support performance, thereby ensuring the lumen space. Specifically, the first branch 3 and the second branch 4 may both include a first surface coating 313 and a first wave ring 312. The first wave ring 312 may be formed by cutting or weaving to form a wave ring structure having a waveform. The first wave rings 312 may be spaced apart or mutually hung to form a mesh structure, or may be provided with both spaced apart portions and mutually hung portions to form a mesh structure. The mutually hung arrangement forms a mesh structure with a higher metal density, which may increase the anchoring force with the small stent. At the same time, the mesh structure may maintain a better lumen morphology when bent, thereby preventing the small stent from bending and occluding when the first branch 3 and the second branch 4 are spirally bent. In order to achieve better long-term patency, the first surface coating 313 of the first branch 3 and the second branch 4 is usually made of PTFE membrane, which has lower porosity and better surface smoothness. Here, the first branch 3 and the second branch 4 will slow down the blood flow rate due to the spiral design, which is easy to cause endothelialization and blockage. The use of PTFE materials that are difficult to endothelialize, or special coating treatment, can ensure the long-term patency of the blood flow of the first branch 3 and the second branch 4. Among them, after the first branch 3 and the second branch 4 are respectively intertwined, they can be connected and fixed by bonding or suturing at the position where the outer surfaces of the first branch 3 and the second branch 4 at least partially contact each other to form a fixing position 5, thereby ensuring the structural stability of the double helix structure, avoiding the loss of its original effect due to the release of the spiral structure during the compression and release and delivery of the stent, and also avoiding the adverse effects of the release of the spiral structure on the patient during long-term use.

[0039] In another embodiment, see Figure 3 and Figure 4The first branch 3 and the second branch 4 can be arranged as an embedded stent, and the distal segment 2 includes an outer covering layer 6, which is coated on the outer surface of the first branch 3 and the second branch 4. The setting of the outer covering layer 6 can cover the spiral winding gaps of the first branch 3 and the second branch 4, thereby increasing the anchoring area of ​​the coated stent 100 between the distal segment 2 and the blood vessel wall through the outer covering layer 6, thereby enhancing the anchoring force of the coated stent 100 in the distal segment 2. Further, the surface roughness of the outer covering layer 6 can be made greater than the surface roughness of the proximal segment 1, thereby increasing the anchoring force by increasing the friction force, for example, the outer covering layer 6 can be used to cover the spiral winding gaps of the first branch 3 and the second branch 4. The covering layer 6 may be made of PET film. Compared with the PTFE film, the PET film has a higher surface roughness due to its own woven structure, which can provide better thrombus climbing properties and thus establish better long-term anchoring force with the blood vessel wall, thereby compensating for the problem of insufficient contact surface between the double helix structure and the blood vessel wall. Among them, in order to better establish a connection with the embedded stent and provide better anchoring to the blood vessel, the outer covering layer 6 can be provided with an outer supporting skeleton and adopt PET film. The supporting skeleton can protect the embedded first branch 3 and second branch 4 while improving the anchoring force with the blood vessel wall. Among them, when the outer surface of the first branch 3 and the second branch 4 is provided with an outer covering layer 6, the fixing position 5 can be provided between the outer covering layer 6 and the first branch 3 or between the outer covering film and the second branch 4, and the outer surface of the first branch 3 and the outer surface of the second branch 4 are at least partially fixedly connected to the outer covering layer 6 at the fixing position 5. In this way, it can be ensured that the first branch 3 and the second branch 4 are fixed relative to the outer covering layer 6, thereby avoiding the release of the spiral structure; further, fixing the outer covering layer 6 relative to the outer surfaces of the first branch 3 and the second branch 4 can enhance their adhesion, avoiding the situation where the outer covering layer 6 is adhered to the blood vessel but the first branch 3 and the second branch 4 are in a non-fixed state, causing the coated stent 100 to shake as a whole under the impact of blood, thereby affecting the overall long-term stability of the coated stent 100.

[0040] In this example, please continue to refer to Figure 4 When the covered stent 100 of the present application is suitable for the iliac artery, the first branch 3 can be used to embed a small external iliac stent implanted in the external iliac artery, and the second branch 4 can be used to embed a small internal iliac stent implanted in the internal iliac artery. Here, since the external iliac artery usually needs to maintain good long-term blood patency, the diameter D1 of the first branch 3 can be greater than or equal to the diameter D2 of the second branch 4 to obtain better blood permeability.

[0041] In one embodiment, see Figure 5 and Figure 6In order to enable the double-helix embedded coated stent 100 provided by the present application to be stably delivered to the target position of the human blood vessel, the present application also provides a delivery system 10, including the coated stent 100 as mentioned above and a delivery device 101. The delivery device 101 usually provided includes a delivery handle 1011, a sheath 1012 and a push rod 1013. The delivery handle 1011 is movably connected to the sheath 1012 and the push rod 1013 respectively. The delivery handle 1011 is used to control the relative position of the sheath 1012 and the push rod 1013, so that the sheath 1012 can move axially relative to the push rod 1013, thereby allowing the coated stent 100 to be disengaged and released from the proximal end of the sheath 1012; wherein, the proximal end of the push rod 1013 is provided with a hook 1014, and the proximal end of the coated stent 100 includes The hook portion includes a hook member 1014 that is detachably connected to the hook portion from the outside of the coated stent 100. Specifically, in addition to the sheath core lumen located in the center, the push rod 1013 can be provided with multiple hook lumens 10121 around the sheath core lumen for the hook member 1014 to pass through and move axially along the lumen. The hook member 1014 can be a plurality of rigid small rods with a hook 10141 at the proximal end. The hook 10141 is used to be detachably connected to the hook portion to fix the proximal end of the coated stent 100 relative to the hook. Then, when the sheath tube 1012 is withdrawn relative to the coated stent 100 and the coated stent 100 is released from the proximal end of the sheath tube 1012, the coated stent 100 can be prevented from being moved as the sheath tube 1012 is withdrawn, thereby affecting the accuracy of the release position. Specifically, although not shown in the figure, the hooking portion of the proximal port of the coated stent 100 can be a portion of the proximal wave coil exposed for hooking with the hook 10141, or a separate hooking structure can be provided, such as a small coil that can be used for hooking.

[0042] Example 2:

[0043] In this embodiment, please refer to Figure 7 and Figure 8The proximal segment 1, distal segment 2, first branch 3 and second branch 4 of the coated stent 100 are basically the same as those in Example 1, except that the first branch 3 and / or second branch 4 include a proximal portion 31 close to the proximal end and a distal portion 32 close to the distal end along the axial direction, and the helix angle A of the proximal portion 31 is greater than or equal to the helix angle B of the distal portion 32. Here, the proximal portion 31 having a larger helix angle means that the lumen of the first branch 3 and / or second branch 4 of the proximal portion 31 has a more inclined angle relative to the radial cross-section of the proximal segment 1, that is, it is closer to a straight-cylindrical lumen. Since in this application, it is expected that both the first branch 3 and the second branch 4 can be implanted in small branches to suggest a passage to the branch blood vessels, before the small stent is implanted in the first branch 3 and the second branch 4, it is necessary to first introduce the guide wire 200 from the proximal end of the first branch 3 and the second branch 4 and then guide the conveyor 101 to release the stent. The proximal portion 31 is provided with a steeper inclined curved structure, and the guide wire 200 is less obstructed when superselectively entering the first branch 3 and the second branch 4, and is easier to enter. The distal portion 32 is more gradual, which can maximize the use of space to increase the number of windings of the first branch 3 and the second branch 4 in the inner cavity of the distal segment 2, thereby increasing the anchoring length of the implanted small stent to improve the connection performance. In addition, due to the spiral structure of the first branch 3 and the second branch 4, starting from the proximal end, the direction of blood flow will change from the original vertical direction to a spiral downward flow. If the angle is too small when just entering, the impact force of the blood flow on the inner wall of the first branch 3 and the second branch 4 will be greater, which can easily cause the stent to shift. Therefore, appropriately increasing the spiral angle A at the proximal portion 31 can reduce the impact force of blood flow on the inner wall of the first branch 3 and the second branch 4. In one embodiment, the spiral angle can be gradually reduced from the proximal portion 31 to the distal portion 32.

[0044] In one embodiment, see Figure 8 When the helix angle A of the part where the proximal portion 31 is connected to the proximal segment 1 is set to the maximum value, the part where the proximal portion 31 is connected to the proximal segment 1 includes a proximal straight tube segment 311, and the central axis of the proximal straight tube segment 311 is parallel to the central axis of the proximal segment 1. With this arrangement, the proximal straight tube segment 311 can follow the straight tube structure of the proximal segment 1. When the guide wire 200 enters from the proximal segment 1, it can more easily enter from the proximal end of the first branch 3 and the second branch 4. Furthermore, the setting of the proximal straight tube segment 311 can maximize the reduction of blood flow erosion on the wall of the small stent, thereby ensuring the long-term stability of the small stent after implantation.

[0045] Example 3:

[0046] In this embodiment, please refer to Figure 9The proximal segment 1, distal segment 2, first branch 3, and second branch 4 of the coated stent 100 are substantially the same as those in Example 1 to Example 2. The difference is that, due to the complexity and diversity of the vascular structure in the human body, two bifurcated blood vessels connected to the same main blood vessel often do not present regular bifurcations, and the degree of bifurcation varies between different patients. Therefore, in order to enable the coated stent 100 provided by the present application to adapt to more types of bifurcated blood vessels, the end of the first branch 3 away from the proximal segment 1 includes a first distal tube segment 301, the end of the second branch 4 away from the proximal segment 1 includes a second distal tube segment 401, and the first distal tube segment 301 is The central axis and the central axis of the second distal tube segment 401 have an angle α, and the angle α is 0°~180°. When the covered stent 100 is placed in the iliac artery and the abdominal aorta, the first branch 3 and the second branch 4 are usually set at an angle α between 0°~90°. Since the two small stents that need to be connected are implanted in the abdominal aorta and are the iliac arteries at both ends, the first branch 3 and the second branch 4 need to be designed symmetrically. For example, both are set at an angle of 45° to the central axis of the proximal segment 1. Here, the symmetrical setting means that the diameter, spiral direction and speed of the spiral of the first branch 3 are the same as those of the second branch 4, so as to meet the symmetry of the blood flow rate and satisfy the blood supply at both ends. In addition, in more extreme cases, α may be greater than 90°, and the angle α is set in the range of 0°~180° to ensure that the covered stent 100 can also be used.

[0047] In one embodiment, see Figure 10 and Figure 11The covered stent 100 provided in the present application can be adapted to extreme diseased blood vessels that need to be blocked in the distal direction and shunted to both sides, such as patients with severe D-type infrarenal aortoiliac artery occlusion. Since the lesion makes the lower edge of the renal artery unable to supply blood, doctors usually choose to partially occlude the lower edge 8 of the renal artery during surgery. The blood supply to the iliac arteries on both sides below the lower edge 8 of the renal artery is provided by other blood vessels. Therefore, only the blood supply to the bilateral renal arteries needs to be provided at the relative position of the aorta and the renal arteries. At this time, the first distal tube segment 301 of the coated stent 100 includes a first distal straight tube segment 3011, and the second distal tube segment 401 includes a second distal straight tube segment 4011. The central axes of the first distal straight tube segment 3011 and the second distal straight tube segment 4011 are both perpendicular to the central axis of the proximal segment 1, and the central axes of the first distal straight tube segment 3011 and the second distal straight tube segment 4011 have an angle β, and the angle β is 180°. At this time, since the first branch 3 and the second branch 4 form two first distal straight tube segments 3011 and second distal straight tube segments 4011 at an angle of 180° on the distal side, under the guidance of the two tube segments, the blood flow is guided in two completely opposite directions to complete the diversion of the blood flow. On this basis, a small stent 7 is respectively connected to realize blood supply to the renal arteries on both sides. Here, in a conventional stent setting, the first branch 3 and the second branch 4 are usually two L-shaped lumen stents, which directly receive the blood flow from the proximal segment 1. At this time, the blood will directly impact the vascular stent at the bend of the L-shaped lumen stent and then be diverted, thereby increasing the vascular pressure at this position, increasing the possibility of lesions. At the same time, the unbuffered blood flow may cause the coated stent 100 to vibrate, thereby affecting the stability of the coated stent 100 and the blood flow. Therefore, the present application adopts the setting of double helix and then divided into subflow, and the spiral structure can avoid blood from directly flushing the bend, thereby effectively slowing down the speed of blood flow, and also slowing down the bending angle at the bend, thereby effectively reducing the impact of blood flushing on the direct and vascular stability, achieving distal occlusion and lateral drainage, while increasing the overall long-term stability of the coated stent 100.

[0048] Example 4:

[0049] In this example, see Figure 12-14The proximal segment 1, distal segment 2, first branch 3 and second branch 4 of the coated stent 100 are substantially the same as those in Examples 1 to 3, except that the first branch 3 and the second branch 4 both include a branch proximal port 41 located at the proximal end and a branch distal port 42 located at the distal end, wherein the branch proximal port 41 and the branch distal port 42 of the first branch 3 and / or the second branch 4 are located on the same side or opposite sides of the distal segment 2 in the circumferential direction. Here, when located on the same side, the number of spiral turns of the first branch 3 and the second branch 4 is exactly one circle or an integer number of circles. Such a setting can facilitate the user to better identify the direction of the branch distal port 42 and / or the branch proximal port 41 when using the coated stent 100, thereby making it easier for the user to identify the direction of the branch distal port 42 and / or the branch proximal port 41. The alignment of the branch distal port 42 with the branch vessel port and the guide wire 200 with the branch proximal port 41 is completed well. Here, it can be understood that the branch proximal port 41 and the branch distal port 42 are set on the same side in the circumferential direction. The position of the two ports can be identified by setting a developing component at any position of the branch proximal port 41 or the branch distal port 42. When the developing component is set at the branch distal port 42, the user aligns the branch distal port 42 with the direction of the branch vessel through the developing component. At this time, the branch proximal port 41 is located in the main blood vessel on the side of the blood vessel wall close to the branch vessel. When the guide wire 200 intervenes, it is only necessary to control the guide wire 200 to offset in that direction to more quickly determine the position of the guide wire 200.

[0050] In one embodiment, please refer to Figure 14 and Figure 15 , when the branch proximal port 41 and the branch distal port 42 of the first branch 3 and the second branch 4 are located on different sides after being wound, taking the small stent embedded in the second branch 4 as an internal iliac coated small stent and the small stent embedded in the first branch 3 as an external iliac coated small stent as an example, specifically, the branch proximal port 41 and the branch distal port 42 are respectively located on opposite sides of the distal segment 2 in the circumferential direction. Here, it should be noted that being located on opposite sides can change the entry path and exit path of the guide wire 200 in the embedded first branch 3 and the second branch 4. The purpose of such a setting is to better enable the covered stent 100 of the present application to be used for treating iliac artery aneurysms and reconstructing the internal iliac artery, to better adapt to a small stent implantation surgery called the mountain-turning technique. Here, the specific operation of the mountain-turning technique is: please refer to Figure 15After the covered stent 100 provided by the present application is placed in the designated position of the iliac artery, the guide wire 200 needs to enter from the opposite femoral artery, through the opposite iliac artery to the iliac artery at the target position. In this process, since the guide wire 200 needs to pass through the iliac artery on the other side after entering from the femoral artery on the other side, and then turn over the intersection of the common iliac artery on the target side and the common iliac artery on the other side before entering the covered stent 100 of the present application, the guide wire 200 needs to bend before entering the common iliac artery on the target side. Here, the curved guide wire 200 has a natural tendency to bounce outward, that is, when entering the common iliac artery on the target side, the curved guide wire 200 advances along the vascular wall of the common iliac artery away from the internal iliac branch blood vessel. At this time, if the proximal branch port 41 and the distal branch port 42 of the second branch 4 are both close to the internal iliac branch blood vessel, then the guide wire 2 00 In the absence of bending adjustment intervention, due to its own elasticity, it will be difficult to enter the second branch 4 away from the internal iliac branch vessel side, and further difficult to enter the target vessel (i.e., the internal iliac branch vessel); if the branch proximal port 41 and the branch distal port 42 of the second branch 4 are both located away from the internal iliac branch vessel side, then although the guide wire 200 can easily enter the second branch 4 without bending adjustment intervention, it is difficult to enter the target vessel (i.e., the internal iliac branch vessel). The branch proximal port 41 and the branch distal port 42 are respectively located on opposite sides of the distal segment 2 in the circumferential direction. When the branch distal port 42 is close to the internal iliac branch vessel, the branch proximal port 41 is just located in the direction of the vessel wall away from the internal iliac branch vessel. At this time, even if the bending adjustment structure is not used for bending, the guide wire 200 can more easily enter the second branch 4 from the branch proximal port 41 of the second branch 4. In an embodiment, the opening of the branch proximal port 41 on the opposite side can also be set as an oblique opening, and the long axis side of the oblique opening is attached to the inner wall of the distal segment 2, thereby ensuring that the guide wire 200 can better enter the branch proximal port 41 of the second branch 4.

[0051] Furthermore, in order to ensure that the branch proximal port 41 and the branch distal port 42 of the second branch 4 are respectively located on opposite sides of the distal segment 2 in the circumferential direction, the number of turns of the second branch 4 along the circumferential direction can satisfy: 0.5+N (N is an integer greater than or equal to 0). Similarly, the branch proximal port 41 and the branch distal port 42 of the first branch 3 can also satisfy the above structure.

[0052] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A stent graft, characterized in that: It includes a main body stent with a tubular body, and the main body stent includes a proximal segment and a distal segment in sequence along the axial direction, and the distal segment includes a first branch and a second branch, the lumen of the first branch and the lumen of the second branch are both connected to the lumen of the proximal segment, the first branch and the second branch are spirally wound around each other and fixed, and the first branch and the second branch are used to increase the anchoring length and contact area of ​​the small stent with the first branch and the second branch after a small stent is implanted respectively; the first branch and the second branch are arranged in the form of an embedded stent, and the distal segment includes an outer covering layer, and the outer covering layer is coated on the outer surface of the first branch and the second branch.

2. The stent graft according to claim 1, wherein: The first branch and / or the second branch includes a proximal portion close to the proximal end and a distal portion close to the distal end along the axial direction, and a helical angle of the proximal portion is greater than or equal to a helical angle of the distal portion.

3. The stent graft according to claim 2, wherein: The portion where the proximal end portion is connected to the proximal segment includes a proximal straight tube segment, and the central axis of the proximal straight tube segment is parallel to the central axis of the proximal segment.

4. The stent graft according to claim 2, wherein: The first branch and / or the second branch each include a plurality of first wave coils arranged along the axial direction, and a plurality of adjacent first wave coils are spaced apart from each other and / or hung together.

5. The stent graft according to claim 1, wherein: The end of the first branch away from the proximal segment includes a first distal tube segment, and the end of the second branch away from the proximal segment includes a second distal tube segment. There is an angle α between the central axis of the first distal tube segment and the central axis of the second distal tube segment, and the range of the angle α is 0°~180°.

6. The stent graft according to claim 5, characterized in that: The first distal tube segment includes a first distal straight tube segment, and the second distal tube segment includes a second distal straight tube segment. The central axes of the first distal straight tube segment and the second distal straight tube segment are both perpendicular to the central axis of the proximal segment, and there is an angle β between the central axes of the first distal straight tube segment and the second distal straight tube segment, and the angle β is 180°.

7. The stent graft according to claim 1, wherein: The surface roughness of the outer cover layer is greater than or equal to the surface roughness of the proximal segment.

8. The stent graft according to claim 7, wherein: The outer surface of the first branch and the outer surface of the second branch are fixedly connected at a position where at least part of them contact each other, or the outer surface of the first branch and the outer surface of the second branch are both at least partly fixedly connected to the outer covering layer.

9. The stent graft according to claim 1, wherein: The diameter of the first branch is greater than or equal to the diameter of the second branch.

10. The stent graft according to claim 1, wherein: The first branch and / or the second branch comprises a proximal branch port located at the proximal end and a distal branch port located at the distal end, and the proximal branch port and the distal branch port are respectively located on the same side or opposite sides of the distal segment in the circumferential direction.

11. A conveying system, characterized in that: It comprises a coated stent and a conveyor as described in any one of claims 1-10, the conveyor comprising a conveying handle, a sheath and a push rod, the conveying handle is movably connected to the sheath and the push rod, and the sheath can move axially relative to the push rod; a hook is provided at the proximal end of the push rod, the proximal end of the coated stent comprises a hook portion, and the hook is detachably connected to the hook portion from the outside of the coated stent.

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