A modular branched stent for treating thoracoabdominal aortic aneurysms

Abstract

The present invention relates to a modular branched stent for treating thoracoabdominal aortic aneurysms, belonging to the technical field of medical devices. The stent is a covered stent, comprising a proximal anchoring module in the descending aorta region, a branched graft module in the visceral artery region, and a distal anchoring module in the abdominal aorta region that are sequentially connected; the number of proximal anchoring modules in the descending aorta region is at least one. The present invention provides a modular branched endovascular graft for treating thoracoabdominal aortic aneurysms in Asian populations. By means of modularization and different combination methods, it can adapt to the anatomical structures of various thoracoabdominal aortic aneurysms, effectively avoiding the time required for customization; the visceral arteries and renal arteries can be reconstructed through branches; sufficient friction can be provided for graft anchoring and bridging through combined anchoring, and the branches can be conveniently selected through the guide wire guiding region, reducing the surgical difficulty and time. Thus, thoracoabdominal aortic aneurysms can be effectively treated, and the occurrence of adverse reactions caused by surgical time and contrast agents can be reduced.

Description

Technical Field

[0001] The present invention relates to a modular branched stent for treating thoracoabdominal aortic aneurysms and belongs to the technical field of medical devices. The present invention defines the direction based on the blood flow direction from proximal to distal. Background Art

[0002] Thoracoabdominal aortic aneurysm (TAAAs) is a localized dilative disease of the thoracic and abdominal aorta secondary to aortic wall weakness. Since TAAA often involves multiple visceral arteries such as the celiac artery, superior mesenteric artery, and bilateral renal arteries, it is a very dangerous aortic disease. The incidence of thoracoabdominal aortic aneurysm is approximately 5.9 / 100,000 person-years. The natural course of this disease often presents with dissection or rupture. Epidemiological studies have found that up to 80% of TAAA patients will eventually experience rupture, resulting in a 5-year survival rate of only 10%-20% for untreated patients. The existing main treatment methods for thoracoabdominal aortic aneurysm include traditional open surgery and endovascular repair techniques. Open surgery has a high mortality and disability rate due to large surgical trauma, long operation time, and many complications. Endovascular repair technology is a new treatment method by implanting an artificial vascular stent in the blood vessel lumen. Compared with open surgery, endovascular treatment of TAAA can significantly reduce the patient's physiological stress, shorten the patient's hospital stay, and reduce the in-hospital mortality rate. Currently, there are the following several techniques for endovascular treatment of thoracoabdominal aortic aneurysm: (1) Hybrid technique. For patients without sufficient distal anchoring area or aneurysms involving visceral arteries, the visceral arteries can be transplanted and reconstructed, and then the thoracic aortic endovascular repair technique can be used to repair the aneurysm. The endovascular repair process of the hybrid technique is simple, and the long-term patency of the anastomosed blood vessels is usually high. However, there are still problems such as huge surgical trauma, high requirements for renal artery anastomosis technology, and high incidence of spinal cord ischemia. (2) Surgeon-modified vascular graft. When there is no suitable vascular graft, the surgeon can adapt to the TAAA anatomy of the patient by fenestration and sewing a finished stent. However, since this technique requires external operation of the sterile graft, there is a certain risk of infection, and this graft has extremely high requirements for the operating skills of vascular surgeons and cannot be used as a conventional endovascular treatment method. (3) Sandwich technique. This technique uses existing endovascular devices and nests multiple small stents as branches in a large covered stent, which is easy to operate. The extrusion of multiple stents in the aortic lumen may lead to blood flow obstruction and branch artery occlusion. And this method is prone to type I endoleak. (4) Octopus technique. Similar to the sandwich technique, the octopus technique also combines multiple existing branched stents to reconstruct the visceral arteries and renal arteries. However, the system structure is extremely complex, it is not easy to see clearly during digital subtraction angiography, and endoleak is also extremely likely to occur at the bridging site between the stents. (5) Branched vascular graft. Although not yet approved by the FDA and with complex operation and application, the branched vascular graft can better conform to the hemodynamic principle, and the patency rate of the branch arteries is high, which is a potential optimal solution for endovascular repair of thoracoabdominal aortic aneurysm. Due to the differences in the aortic anatomical structure and the range of involved branch blood vessels in TAAA patients, custom-made branched vascular grafts are a relatively common choice for endovascular repair of thoracoabdominal aortic aneurysm.The customized grafts can better fit the characteristics of the patient's aortic aneurysm, but these grafts often take 10 - 12 weeks to prepare, while the off-the-shelf stents can greatly shorten the waiting time for treatment. In addition, the current thoracic and abdominal aortic branched vascular grafts are mainly of an integral structure and cannot well adapt to the complex anatomical structure of the patient. By modularizing the integral branched vascular grafts, the individualized needs of the patient and mass production can be better taken into account. Summary of the Invention

[0003] The object of the present invention is to solve the technical problem of how to overcome the defects of the prior art and obtain a technology that can better adapt to the complex anatomical structure of the patient, and by modularizing the integral branched vascular grafts, better take into account the individualized needs of the patient and mass production.

[0004] To achieve the above object, the technical solution adopted by the present invention is to provide a modular branched stent for treating thoracic and abdominal aortic aneurysms, which is a covered stent and includes a proximal anchoring module in the descending aorta region, a branched graft module in the visceral artery region, and a distal anchoring module in the abdominal aorta region that are connected in sequence; the proximal anchoring module in the descending aorta region is communicated with the distal anchoring module in the abdominal aorta region through the branched graft module in the visceral artery region; the number of the proximal anchoring modules in the descending aorta region is at least one.

[0005] Preferably, the proximal anchoring module in the descending aorta region is a conical covered stent, which includes a metal stent main structure and a stent covering provided on the surface of the main structure; the diameter of the proximal end of the covered stent is larger than that of the distal end; barbs one extending outward are provided on the proximal outer peripheral wall, and barbs two extending inward are provided on the distal inner wall.

[0006] Preferably, after a plurality of the proximal anchoring modules in the descending aorta region are connected in sequence, the distal end of the proximal anchoring module in the descending aorta region is connected to the proximal end of the branched graft module in the visceral artery region.

[0007] Preferably, the connection between the proximal anchoring modules in the descending aorta region is that the distal end of one proximal anchoring module in the descending aorta region is connected to the proximal end of another proximal anchoring module in the descending aorta region.

[0008] Preferably, the visceral artery division branch graft module includes a proximal stent channel, a front and rear guide wire guiding area, a dorsal short branch, a ventral short branch, and a distal stent channel; a front and rear guide wire guiding area is provided between the proximal stent channel and the distal stent channel; the proximal stent channel is connected to the distal stent channel through a stent, and is connected to the ventral short branch and the dorsal short branch through the front and rear guide wire guiding area; the dorsal short branch and the ventral short branch are respectively provided in the front and rear guide wire guiding area; the central axes of the dorsal short branch and the ventral short branch are parallel to the central axis of the distal stent channel; the diameter of the proximal stent channel is larger than the diameter of the distal stent channel; an outwardly extending barb one is provided on the outer peripheral wall of the proximal stent channel, and an inwardly extending barb two is provided on the inner wall of the distal stent channel.

[0009] Preferably, the outer shape of the front and rear guide wire guiding area is conical, and the diameter of the proximal end of the front and rear guide wire guiding area is larger than that of the distal end; the front and rear guide wire guiding area is provided with a hollow ventral guide wire guiding area and a dorsal guide wire guiding area; two hollow ventral short branches extend distally from the ventral guide wire guiding area; two hollow dorsal short branches extend distally from the dorsal guide wire guiding area.

[0010] Preferably, the distal anchoring module in the abdominal aorta area includes a proximal straight cylindrical stent and two distal branch stents; the proximal straight cylindrical stent and the two distal branch stents are integrally formed; the two distal branch stents are provided as iliac artery branch stents, and suture knots are provided on the film of the iliac artery branch stents; an outwardly extending barb one is provided on the outer peripheral wall of the proximal straight cylindrical stent.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] 1. Adopting a modular design: The existing commercial vascular grafts at home and abroad are all integrally designed, and it is necessary to have sufficient proximal and distal anchoring areas while the graft branches correspond to the branch vessels. This is often not easy to achieve in the thoracoabdominal aortic aneurysm with complex and variable anatomical conditions, thus affecting the application rate of the graft. The endovascular graft of the present invention is divided into three modules, namely the proximal anchoring module in the descending aorta area (hereinafter referred to as Module 1), the visceral artery division branch graft module (hereinafter referred to as Module 2), and the distal anchoring module in the abdominal aorta area (hereinafter referred to as Module 3). Module 1 is a variable cone straight tube graft of various lengths, used for proximal anchoring and meeting the diameter change when the descending aorta migrates to the abdominal aorta; Module 2 is a general-purpose branched graft, which bridges Module 1 and emits four branches to reconstruct the blood supply of the celiac trunk, superior mesenteric artery, and bilateral renal arteries; Module 3 is a bifurcated graft, which distally anchors the common iliac artery while bridging Module 2, and can also be bridged with a commercial branched stent in the endovascular repair of the abdominal aorta.

[0013] The use of modular design can effectively address the stringent requirements of existing off-the-shelf grafts for the patient's aorta. The active lesions of the patient's aorta are divided into three segments. Appropriate graft modules are selected according to the lesion characteristics of different segments, and visceral arteries and renal arteries are reconstructed through branch bridging stents of visceral arteries, thus greatly increasing the adaptability of the endovascular graft of the present invention. At the same time, modular grafts can also avoid problems such as overly long waiting times for customized vascular grafts. Different combinations of the three modules of the graft meet the anatomical requirements of the vascular graft for visceral branches and proximal and distal anchoring zones, thereby achieving the maximum matching of the patient's anatomical structure.

[0014] 2. Graft combined anchoring: The fixation degree of the anchoring zone and the tightness of the bridging between stents have a significant impact on the treatment outcome of endovascular vascular grafts. Modular stents require more secure inter-module anchoring to prevent the occurrence of endoleakage and displacement. The present invention designs a combined anchoring system for modular branched vascular grafts. Through a combination of various anchoring and bridging means, the treatment effectiveness of the graft is improved. The proximal metal barbs of module one face the outside of the stent to provide more secure anchoring; the lower half of the metal barbs face the inside of the stent to increase the friction when bridging with module two. The proximal end of module two uses barbs to increase the bridging tightness with module one, and internal barbs are also provided in the lower half to enhance the connection strength with module three. The proximal end of module three also adopts a barb structure, and at the same time, a knot is used at the distal end to increase the anchoring strength at the distal end. Through the combined anchoring system between multiple modules, secure vascular anchoring and inter-module bridging are provided, increasing the application effectiveness of this type of vascular graft.

[0015] 3. Guide wire guiding area design: In endovascular vascular grafts with branches, the graft and the branches are often directly connected without any transition. During the endovascular surgery process, the surgeon needs to repeatedly perform angiography under fluoroscopy and operate the guide wire into the corresponding branch, which is somewhat difficult. And this problem is more obvious during the endovascular treatment of multi-branched stents. Therefore, a guide wire guiding area is innovatively designed in this graft. The guiding area is a funnel-shaped large branch, and 2 visceral arteries or 2 renal artery branches are connected below the guiding area. There is a guide wire guiding area in front of and behind the main body of module two. The front guiding area includes the celiac trunk branch and the superior mesenteric artery branch; the rear guiding area includes the left and right renal artery branches. The surgeon only needs to relatively easily place the guide wire into the larger guiding area first and then make a slight adjustment to enter different branches, which can effectively reduce the operation time and reduce the use of contrast agent.

[0016] 4. Suitable for the anatomical structure of Asian patients: Due to their smaller physique, the diameters of the aorta, renal arteries, and visceral arteries in the Asian population are all smaller than those in the Western population. Overseas endovascular grafts for TAAA may not be effectively applied to Asian patients with thoracoabdominal aortic aneurysms. Although the domestic G-branch stent has adjusted the diameter of the branches, the diameters of the celiac trunk and the superior mesenteric artery are still relatively large. According to the anatomical characteristics of Asian blood vessels, the present invention reduces the diameter of the branch stent to better match the corresponding arteries, and provides a more flexible and free choice when matching the branch arteries through a parallel branch design. In addition, by designing an extended branch part to obtain a longer branch artery bridging area, it can be better applied to the revascularization of the visceral branches and bilateral renal arteries of Asian patients. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of the proximal anchoring module in the descending aorta region of the present invention.

[0018] Figure 2 It is a schematic structural diagram of the branch graft module in the visceral artery region of the present invention.

[0019] Among them, Figure A is the front view, Figure B is the rear view, and Figure C is the top view.

[0020] Figure 3 It is a schematic structural diagram of the distal anchoring module in the abdominal aorta region of the present invention.

[0021] Figure 4 It is a schematic rear view structural diagram of the present invention connecting the proximal anchoring module in the descending aorta region, the branch graft module in the visceral artery region, and the distal anchoring module in the abdominal aorta region in sequence.

[0022] Figure 5 It is a schematic front view structural diagram of the present invention connecting the proximal anchoring module in the descending aorta region, the branch graft module in the visceral artery region, and the distal anchoring module in the abdominal aorta region in sequence.

[0023] Reference numerals: 1. Barbed hook 1; 2. Metal stent; 3. Stent membrane; 4. Barbed hook 2; 5. Ventral wire guiding area; 6. Dorsal short branch; 7. Ventral short branch; 8. Dorsal wire guiding area; 9. Iliac artery branch stent; 10. Suture knot; 11. Proximal anchoring module in the descending aorta region; 12. Branch graft module in the visceral artery region; 13. Distal anchoring module in the abdominal aorta region. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] To make the present invention more obvious and understandable, the preferred embodiments are described in detail below in conjunction with the accompanying drawings:

[0025] As Figures 1-5As shown in the figure, the technical solution adopted by the present invention is to provide a modular branched stent for treating thoracoabdominal aortic aneurysm, which is a covered stent and includes a proximal anchoring module 11 in the descending aorta region, a branched graft module 12 in the visceral artery region, and a distal anchoring module 13 in the abdominal aorta region that are connected in sequence; the proximal anchoring module 11 in the descending aorta region is communicated with the distal anchoring module 13 in the abdominal aorta region through the branched graft module 12 in the visceral artery region; the number of the proximal anchoring modules 11 in the descending aorta region is at least one. The proximal anchoring module 11 in the descending aorta region is set as a conical tube-shaped covered stent, which includes a metal stent 2 main body structure and a stent covering 3 provided on the surface of the main body structure; the diameter of the proximal end of the covered stent is larger than that of the distal end; barbs one 1 extending outward are provided on the proximal outer peripheral wall, and barbs two 4 extending inward are provided on the distal inner side wall. After a plurality of proximal anchoring modules 11 in the descending aorta region are connected in sequence, the distal end of the proximal anchoring module 11 in the descending aorta region is connected to the proximal end of the branched graft module 12 in the visceral artery region. The connection between the proximal anchoring modules 11 in the descending aorta region is that the distal end of one proximal anchoring module 11 in the descending aorta region is connected to the proximal end of another proximal anchoring module 11 in the descending aorta region. The branched graft module 12 in the visceral artery region includes a proximal stent channel, a front and rear wire guiding area, a dorsal short branch 6, a ventral short branch 7, and a distal stent channel; the proximal stent channel is connected to the distal stent channel by a stent, and is communicated with the ventral short branch 7 and the dorsal short branch 6 through the front and rear wire guiding area; the central axes of the dorsal short branch 6 and the ventral short branch 7 are parallel to the central axis of the distal stent channel; the diameter of the proximal stent channel is larger than that of the distal stent channel; barbs one 1 extending outward are provided on the outer peripheral wall of the proximal stent channel, and barbs two 4 extending inward are provided on the inner side wall of the distal stent channel. The front and rear wire guiding area is shaped like a cone, and the diameter of the proximal end of the front and rear wire guiding area is larger than that of the distal end; the front and rear wire guiding area is provided with a hollow ventral wire guiding area 5 and a dorsal wire guiding area 8; two hollow ventral short branches 7 extend distally from the ventral wire guiding area 5; two hollow dorsal short branches 6 extend distally from the dorsal wire guiding area 8. The distal anchoring module 13 in the abdominal aorta region includes a proximal straight tube-shaped stent and two distal branch stents; the proximal straight tube-shaped stent and the two distal branch stents are integrally formed; the two distal branch stents are set as iliac artery branch stents 9, and suture knots 10 are provided on the covering of the iliac artery branch stents 9; barbs one 1 extending outward are provided on the outer peripheral wall of the proximal straight tube-shaped stent.

[0026] Embodiment

[0027] The endovascular graft of the present invention is divided into three modules, namely the proximal anchoring module in the descending aorta region (hereinafter referred to as Module 1), the branched graft module in the visceral artery region (hereinafter referred to as Module 2), and the distal anchoring module in the abdominal aorta region (hereinafter referred to as Module 3).

[0028] Among them, Module 1, namely the proximal anchoring module 11 in the descending aorta region: is a variable-taper straight tube graft. The proximal diameter is 28 - 46 mm, the distal diameter is 18 - 35 mm, and it has a tapered design with a gradually decreasing diameter from the proximal end to the distal end. The length of Module 1 is 100 - 300 mm to adapt to different proximal aortic anchoring positions. While achieving sufficient proximal anchoring, it subsequently bridges the branch graft modules in the visceral artery region at the distal end. When the length of a single Module 1 is insufficient, another Module 1 can also be implanted within Module 1 to complete the connection to achieve a sufficient length.

[0029] As Figure 1 shown, the proximal end of the stent is provided with a metal barb 1 extending outwardly, which can be made of nitinol and is used for proximal anchoring of blood vessels to firmly anchor the stent on the blood vessel wall; the metal stent 2 serves as the main structure and is a Z-shaped stent to enhance the strength of the stent, which can be made of nitinol; a stent membrane 3 is provided on the main structure, which can be made of nylon or polytetrafluoroethylene, and can effectively isolate the blood flow while preventing lumen occlusion; the distal end is provided with a metal barb 2 extending inwardly, which can be made of nitinol and is used to firmly bridge the next module to prevent displacement during the bridging of blood vessel grafts.

[0030] Module 1 is a variable-taper straight tube graft, and the tapered design with a gradually decreasing diameter can meet the diameter change when the descending aorta migrates to the abdominal aorta in patients. Since the descending aorta often requires a sufficient anchoring area to fix the graft and fully isolate the blood flow. Since the modular stent isolates the aneurysm cavity through multiple stent bridges, higher requirements are put forward for the stability of stent anchoring and bridging. The metal barb design extending outwardly at the proximal end is used for proximal anchoring of blood vessels to firmly anchor the stent on the blood vessel wall; the metal barb extending inwardly at the distal end is used to firmly bridge the next module and prevent displacement during the bridging of blood vessel grafts.

[0031] Module II, namely the visceral artery branch graft module 12; Module II is the core component of this design and is a general-purpose module suitable for most thoracoabdominal aortic aneurysms. Its function is to reconstruct the blood supply of the celiac artery, superior mesenteric artery, and bilateral renal arteries while isolating the aneurysm cavity. The proximal diameter of Module II is 20 - 38 mm, and the length is 20 - 30 mm. There are two wide-mouth branch openings, the ventral wire guiding area 5 and the dorsal wire guiding area 8, at the branch part as wire guiding areas, with a length of 5 - 8 mm. The anterior guiding area (ventral wire guiding area 5) is narrower, and it contains two branches that are symmetrically positioned, namely the ventral short branches 7; both branches can be used as branches of the celiac artery or superior mesenteric artery to provide a more flexible choice of branch vessels. The posterior guiding area (dorsal wire guiding area 8) is wider and also contains two branches that are symmetrically positioned left and right, namely the dorsal short branches 6, with a relatively large distance between them. The directions of the four branches are all downward, with a diameter of 6 mm and a length of 10 mm. Module II can be released slightly above the visceral artery area and fixed within Module I. The branch vessels reconstruct the branch artery blood supply through a bridging covered stent with a diameter of 6 - 8 mm. For 6-mm branch vessels, a new type of balloon-expandable covered stent can be selected to ensure firm proximal anchoring. The distal anchoring area of Module II is 25 mm long and has a diameter of 12 - 20 mm.

[0032] As Figure 2 shown, the proximal end of the stent extends outward with a metal barb I 1, which can be made of nitinol alloy and is used for proximal anchoring of the blood vessel to firmly anchor the stent on the blood vessel wall; the main structure is a metal stent 2, which is a Z-shaped stent, and the covered parts include the proximal stent body of Module II, the anterior and posterior wire guiding areas, and the distal stent body to enhance the strength of the stent and prevent the stent body and wire guiding areas from being compressed and deformed. It can be made of nitinol alloy; the stent is provided with a stent covering 3, which can be made of nylon or polytetrafluoroethylene, and can effectively isolate the blood flow and prevent lumen occlusion at the same time; the ventral wire guiding area 5 has a relatively large proximal opening, about 60 degrees, and gradually narrows at the distal end and extends two short branches (ventral short branches 7) to reconstruct the visceral artery; the two short branches (dorsal short branches 6) extended from the dorsal wire guiding area 8 are used to reconstruct the bilateral renal arteries. A ring-shaped stent is used on the branches to improve the flexibility and bendable angle of the branches. The outside of the stent is covered with polyester fiber to prevent lumen occlusion while reconstructing the blood flow; the two short branches (ventral short branches 7) extended from the ventral wire guiding area are used to reconstruct the celiac artery and superior mesenteric artery. A ring-shaped stent is used on the branches to improve the flexibility and bendable angle of the branches. The outside of the stent is covered with polyester fiber to prevent lumen occlusion while reconstructing the blood flow; the distal end is provided with a metal barb II 4 that extends inward, which can be made of nitinol alloy and is used to firmly bridge the next module to prevent displacement during the bridging of the vascular graft; the dorsal wire guiding area 8 has a relatively large proximal opening, about 150 degrees, and gradually narrows at the distal end and extends two short branches (dorsal short branches 6) to reconstruct the visceral artery.

[0033] Module 2 is designed as a general-purpose module suitable for most thoracoabdominal aortic aneurysms. Its function is to reconstruct the blood supply to the celiac artery, superior mesenteric artery, and bilateral renal arteries while isolating the aneurysm cavity. The proximal diameter, length, and branch opening diameter of Module 2 are all designed according to the Asian aortic standards. During stent deployment and angiography, the branch artery openings are small and difficult to manipulate and pass through under angiography. By designing the wire guiding area structure, the surgical difficulty and operation time are effectively reduced, and the use of contrast agent is also reduced. Each of the front and rear guiding areas contains two branches, which are symmetrically positioned. Both branches can serve as branches of the celiac artery or superior mesenteric artery, providing more flexible choices for branch vessels. Due to the flat and long structure of the wire guiding area, it is prone to deformation. A Z-shaped stent is used to prevent it from being compressed and deformed. All four branches use annular stents to improve the flexibility and bendable angle of the branches. The stent is covered with polyester fiber to prevent lumen occlusion while reconstructing blood flow. The proximal metal barb structure of Module 2 is also designed for firm bridging to prevent stent displacement.

[0034] Module 3 is the distal anchoring module 13 in the abdominal aorta area;

[0035] Module 3 is a commercialized bifurcated graft, similar to the abdominal aortic branch stent. The proximal part is a straight stent with a diameter of 15 - 25 mm and a length of 15 - 30 mm. The distal part is connected to two iliac artery branches with a length of 20 - 40 mm and a diameter of 10 mm. The proximal anchoring area also uses a barb structure to increase the friction with Module 2 during bridging; the distal anchoring area of the graft is covered with a film with suture knots 10 to increase the friction between the graft and the iliac artery, preventing endoleakage and displacement. It is also possible to select a suitable commercialized abdominal aortic branch graft according to the patient's TAAA anatomical structure, making the combination more abundant and convenient.

[0036] As Figure 3 shown, the proximal part of the stent is provided with a metal barb 1 extending outward, which can be made of nitinol material and is used for proximal anchoring of blood vessels to firmly anchor the stent on the blood vessel wall; the stent is provided with a stent covering film 3, which can be made of nylon material or polytetrafluoroethylene, and can effectively isolate blood flow while preventing lumen occlusion; the main body structure is a metal stent 2, which is a Z-shaped stent, covering the proximal stent main body of Module 3 and the distal iliac artery branch stent 9 to enhance the strength of the stent and prevent the stent main body from being compressed and deformed. It can be made of nitinol material; two iliac artery branch stents 9 extending from the proximal stent main body are used to reconstruct the bilateral iliac arteries and the distal anchoring; suture knots 10 are provided on the iliac artery branch stent 9, located outside the iliac artery branch covering film, to increase the friction between the iliac artery branch and the iliac artery, preventing stent displacement and endoleakage.

[0037] The proximal anchoring region of Module III also adopts a barbed structure to increase the friction with Module II during bridging; the distal anchoring region of the membrane is designed with suture knots to increase the friction between the graft and the iliac artery, preventing endoleakage and displacement.

[0038] As Figure 4 , shown in Figure 5, in a thoracoabdominal aortic aneurysm, Module I with a diameter suitable for the patient's aorta is released at an appropriate position proximal to the aneurysm cavity to firmly anchor to the vessel wall, fixing the proximal barbs to the artery; Module II is released distal to Module I, with a certain overlapping part between the proximal and distal ends of Module II to enhance friction, and the inward-facing barb II at the distal end of Module I hooks into the membrane of the proximal end of Module II, while the proximal barb I of Module II hooks into the distal end of Module I to ensure a firm bridge, and to ensure that Module II is located above the celiac trunk, superior mesenteric artery, and bilateral renal arteries to ensure subsequent reconstruction of the visceral artery blood flow through the branches. Module III is released distal to Module II, with a certain overlapping part between Module II and Module III to enhance friction, and the proximal barb I of Module III hooks outward into the distal end of Module II to ensure a firm bridge. The iliac artery branches at the distal end of Module III are anchored to the left and right iliac arteries, with a certain length of the iliac artery branches of Module III in the iliac artery to ensure firm distal anchoring and avoid the formation of endoleakage.

[0039] Through the two branches of the ventral wire guiding region, a covered stent or balloon-expandable covered stent with a diameter of 6 - 8 mm is bridged to reconstruct the blood supply of the branched arteries. The bridging stent needs to have a certain overlap with the branches of Module II to ensure a firm proximal bridge, and the distal end can freely choose to be anchored to the celiac trunk or superior mesenteric artery to reconstruct the visceral blood flow. Through the two branches of the dorsal wire guiding region, a covered stent or balloon-expandable covered stent with the same diameter is bridged to reconstruct the blood supply of the branched arteries. The bridging stent needs to have a certain overlap with the branches of Module II to ensure a firm proximal bridge, and the distal end can freely choose to be anchored to the left and right renal arteries to reconstruct the blood flow of the bilateral renal arteries.

[0040] The present invention provides a novel modular branched endovascular graft for treating thoracoabdominal aortic aneurysms in the Asian population. This off-the-shelf graft is designed for the Asian population and can adapt to the anatomical structures of various thoracoabdominal aortic aneurysms through modularization and different combination methods, effectively avoiding the time required for customization, and reconstructing the visceral arteries and renal arteries involved by the aneurysm through the branches. In addition, the combined anchoring design provides sufficient friction for the anchoring and bridging of the graft, and a wire guiding region is innovatively designed to ensure the convenience of selecting branches during the angiography process, reducing the surgical difficulty and time. Thus, it effectively treats thoracoabdominal aortic aneurysms and reduces the occurrence of surgical time and adverse reactions to contrast agents.

[0041] The above are only the preferred embodiments of the present invention, and do not impose any formal or substantial limitations on the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the premise of the present invention, several improvements and supplements can still be made, and these improvements and supplements should also be regarded as within the protection scope of the present invention. Any equivalent changes made by those skilled in the art who are familiar with this specialty, without departing from the spirit and scope of the present invention, by making some changes, modifications and evolutions using the technical content disclosed above, are all equivalent embodiments of the present invention; at the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the substantial technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A modular branched stent for treating thoracoabdominal aortic aneurysm, which is a covered stent, Characterized in that: It includes a proximal anchoring module in the descending aorta area, a branched graft module in the visceral artery area, and a distal anchoring module in the abdominal aorta area that are connected in sequence; the proximal anchoring module in the descending aorta area is connected through the branched graft module in the visceral artery area and the distal anchoring module in the abdominal aorta area; the number of proximal anchoring modules in the descending aorta area is at least one; The proximal anchoring module in the descending aorta area is set as a conical cylindrical covered stent, including a metal stent main structure and a stent covering provided on the surface of the main structure; the diameter of the proximal end of the covered stent is larger than that of the distal end; barbs one extending outward are provided on the proximal outer peripheral wall, and barbs two extending inward are provided on the distal inner side wall; The branched graft module in the visceral artery area includes a proximal stent channel, a front and rear wire guiding area, a dorsal short branch, a ventral short branch, and a distal stent channel; a front and rear wire guiding area is provided between the proximal stent channel and the distal stent channel; the proximal stent channel is connected to the distal stent channel through a stent and is connected to the ventral short branch and the dorsal short branch through the front and rear wire guiding area; the dorsal short branch and the ventral short branch are respectively provided in the front and rear wire guiding area; the central axes of the dorsal short branch and the ventral short branch are parallel to the central axis of the distal stent channel; the diameter of the proximal stent channel is larger than that of the distal stent channel; barbs one extending outward are provided on the outer peripheral wall of the proximal stent channel, and barbs two extending inward are provided on the inner side wall of the distal stent channel; The distal anchoring module in the abdominal aorta area includes a proximal straight cylindrical stent and two distal branch stents; the proximal straight cylindrical stent and the two distal branch stents are integrally formed; the two distal branch stents are set as iliac artery branch stents, and suture knots are provided on the covering of the iliac artery branch stents; barbs one extending outward are provided on the outer peripheral wall of the proximal straight cylindrical stent.

2. A modular branched stent for treating thoracoabdominal aortic aneurysm according to claim 1, Characterized in that: After multiple proximal anchoring modules in the descending aorta area are connected in sequence, the distal end of the proximal anchoring module in the descending aorta area is connected to the proximal end of the branched graft module in the visceral artery area.

3. A modular branched stent for treating thoracoabdominal aortic aneurysm according to claim 2, Characterized in that: The connection between the proximal anchoring modules in the descending aorta area is that the distal end of one proximal anchoring module in the descending aorta area is connected to the proximal end of another proximal anchoring module in the descending aorta area.

4. A modular branched stent for treating thoracoabdominal aortic aneurysm according to claim 1, Characterized in that: The outer shape of the front and rear wire guiding area is set as a conical shape, and the diameter of the proximal end of the front and rear wire guiding area is larger than that of the distal end; the front and rear wire guiding area is provided with a hollow ventral wire guiding area and a dorsal wire guiding area; two hollow ventral short branches extend distally from the ventral wire guiding area; two hollow dorsal short branches extend distally from the dorsal wire guiding area.

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