Vascular reconstruction devices

Abstract

The present invention relates to medical devices, and more particularly to an arterial reconstruction device. The present invention provides an aortic reconstruction device that allows for the simple, smooth, and effective completion of treatment for an aortic aneurysm or dissection and the reconstruction of adjacent branch arterial vessels without affecting the vascular perfusion of the adjacent branch arteries. The reconstruction device includes a stent graft and an expansion member that can be positioned within the stent graft to expand to a diameter no smaller than the inner diameter of the stent graft.

Description

[Technical Field]

[0001] The present invention relates to medical devices, and more particularly to arterial reconstruction devices. [Background technology]

[0002] Aortic aneurysms and aortic dissections are highly aggressive human vascular diseases. Aortic aneurysms arise from diffuse abnormal dilatation of the blood vessel, with aneurysmal rupture being the primary risk. Longitudinal aortic fissures, on the other hand, are characterized by a tear in the intima, widening the hiatus, and the creation of a true or false lumen. These conditions not only pose a risk of rupture but also significantly impact the blood supply to branch vessels and organs.

[0003] Aortic aneurysms primarily occur in the abdominal aorta and thoracic aorta, but can also occur in the aortic arch. Interventional endoluminal treatment using stent grafts has gradually replaced open surgery as the treatment of choice for thoracic and abdominal aortic dissection due to its minimally invasive nature. However, the following issues remain: when aortic dissection is located in or near a branch vessel, the available normal aortic segment for stent graft fixation at the site is often limited because it does not occlude or obstruct normal blood perfusion of the branch artery. The current consensus for endoluminal treatment is that a healthy aorta within 15 mm of the true aneurysm neck must be secured for stent graft fixation. When a stent graft of sufficient length cannot be provided in a healthy aortic segment, patients often have to opt for highly invasive surgical intervention. Currently, the bare area of the stent is designed at the proximal or distal end of the stent graft, allowing the bare area of the stent to be aligned with the branch vessel, thereby expanding the fixation area to a certain extent. However, the problem with this approach is that in order to prevent the bare area of the stent from occluding the branch vessel, the bare area of the stent is often very sparse. Although it can cover the branch vessel and increase the fixation area, it does not provide sufficient radial support to ensure fixation, and there is a risk of stent graft displacement. For the same reason, in the case of aortic arch dissection, due to its proximity to the left common carotid artery and left subclavian artery, there are currently no effective and convenient interventional devices for endoluminal treatment. Therefore, surgical treatment remains the mainstream, and patients must face surgical trauma and risks.

[0004] Aortic dissection, which occurs most frequently in men aged 50-70, is the leading cause of aortic-related death in humans. Its mechanism is primarily due to degenerative changes in the aortic intima, allowing blood flow to penetrate the intima, resulting in separation and the formation of an aneurysmal instability. It is extremely dangerous, with a one-year mortality rate of up to 90% if left untreated. In recent years, the increasing incidence of aortic dissections in Japan has attracted attention. Aortic dissections are classified into Stanford type A and type B, depending on whether or not the ascending aorta is involved. Type A involves the ascending aorta and ruptures the ascending aorta, aortic arch, and proximal end of the descending aorta. Type B aortic dissections, which do not involve the ascending main trunk, primarily rupture the proximal end of the descending aorta. Current treatment status: For type A dissections, which often involve part of the arch branch arteries, open surgery (such as venous surgery or thoracotomy) is currently the norm to remove the proximal rupture and replace the proximal lesion with a vascular prosthesis. If there is a possibility of a distal rupture, which is often adjacent to a branch artery, open treatment or staged treatment is performed. For type B dissections, endoluminal closure of the proximal rupture with a stent graft is the preferred treatment, but there is still no good solution when the proximal or distal rupture extends to a branch artery.

[0005] In summary, it is currently difficult to ensure stent graft fixation for adjacent branch vessels, such as aortic arch disease or abdominal aortic disease, while maintaining normal branch artery perfusion. While treatments such as fenestration and branching brackets are available, they have not yet been widely adopted due to their limited applicability and operational difficulties. Two methods, preoperative and intraoperative, allow for the stent graft "window" to be aligned with the branch artery and successfully opened while considering the branch vessel perfusion. The difficulty with preoperative fenestration is how accurately the window is aligned with the branch vessel during surgery. The limitation of intraoperative fenestration is the time required for branch vessel closure, which often leads to ischemic injury, especially in the aortic arch, which contributes to the intracranial blood supply. The limitation of branch stents is the variability in the anatomical location of branch vessels, making it difficult to adapt specific branch stent grafts of different sizes and positions to different branch vessel anatomy. Although there have been attempts to combine fenestration with reimplantation of branch stents, most of these have limited application and have difficulty addressing issues of alignment and intraoperative branch artery ischemia.

[0006] The present invention provides an aortic reconstruction device that allows for simple, smooth, and effective completion of treatment for aortic aneurysm or dissection and reconstruction of adjacent branch arteries without affecting vascular perfusion in the adjacent branch arteries. The main mechanism of action of this device is to first place a stent graft with temporary inflow access for an aortic aneurysm or dissection adjacent to a branch artery, fixating it while allowing blood from the aorta to pass through the branch artery. During intraoperative opening of the branch artery opening, the temporary inflow access of the stent graft maintains blood perfusion in the branch artery during the intraoperative fenestration process. After the fenestration process is completed or after placing an additional branch stent graft in the branch artery, the tubular shape of the stent graft body can be restored by re-placement of a bare stent or balloon expansion, allowing complete reconstruction of the aorta and adjacent branch arteries without affecting blood perfusion in the branch arteries.

[0007] In one embodiment, the present invention provides an aortic reconstruction device comprising a stent graft (100) with temporary inflow access and a bare stent (200), as shown in Figure 1A. The main body of the stent graft (100) comprises a first stent graft segment (110) (the end of the clad stent closest to the heart, referred to as the proximal end in the following text), a second stent graft segment (120), and a third stent graft segment (130) (the end of the stent graft farther from the heart, referred to as the distal end in the following text), each of which comprises a stent frame and a covered membrane thereover, wherein the second stent graft segment comprises a fenestration region (121). The surface of the stent graft (100) includes at least one temporary inflow access (140), and may further include a proximal end access (141), a fenestration region access (142), and a distal end access (143). In this configuration, the proximal access (141) is located in the first stent graft (110), the fenestration area access (142) is included in the fenestration area (121), and the distal access (143) is located in the third stent graft (130). The fenestration area (121) corresponds to the opening area of one or more adjacent branch arteries. The temporary inflow access (140) serves to allow blood to flow to the adjacent branch arteries through the temporary inflow access (140) when the stent graft (100) is implanted in a blood vessel, preventing the stent graft from obstructing blood perfusion when closing the branch artery opening during intraoperative fenestration. Once intraoperative opening is completed in the opening area (121) or after further branch stents are placed in the branch arteries, the temporary inflow access (140) can be opened and transformed into a concave shape to form a complete tubular structure with the stent graft (100).

[0008] In one embodiment, the aortic reconstruction device of the present invention is used to repair one or more proximal end dissecting lacerations in the arch. [Brief explanation of the drawings]

[0009] [Figure 1A]One stent graft (100) of the present invention has a main body consisting of a stent frame with a membrane covering it, and may comprise a first stent graft segment (110) (the end of the stent graft closest to the heart), a second stent graft segment (120), and a third stent graft segment (130) (the end of the stent graft farther from the heart), where the second stent graft segment has a fenestration region (121). The surface of the stent graft (100) includes at least one temporary inflow access (140), and may further include a proximal end access (141), a fenestration region access (142), and a distal end access (143). In the figure, the proximal access (141) is located in the first stent graft segment (110), the fenestration access (142) is contained within the fenestration region (121), and the distal access (143) is located in the third stent graft segment (130). The fenestration regions (121) correspond to the ostia of one or more adjacent branch arteries. Adjacent fenestration regions (121) are spaced apart by an internally concave skeleton (122). [Figure 1B] FIG. 1 shows a cross section of a temporary inflow access (140), which can be any shape, such as circular, slotted, V-shaped, straight, etc. [Figure 1C] It is shown that the temporary inflow access (140) can be opened to become cylindrical with the main body of the stent graft, ie, to become a full circle when expanded without changing circumference. [Figure 1D] It is shown that the temporary inflow access (140) can be distributed in a helical, linear or any other curvilinear trajectory through the surface of the stent graft. [Figure 2A] It is shown that the temporary inflow access (140) can begin with the first stent graft segment (110), i.e., the proximal end, and extend through the second stent graft segment (120), where it can then terminate. [Figure 2B]It is shown that the temporary inflow access (140) may begin with the third stent graft segment (130), ie the distal end, and extend to terminate after the second stent graft segment (120). [Figure 3A] The stent graft in the fenestration area (121) shows an internal concave skeleton (122) connected by stitches via one or more stitch points. [Figure 3B] Shown is an internal concave skeleton (122) realized in a ribbon structure within the fenestration area (121) woven together with the covering membrane. [Figure 3C] An internally concave skeleton (122) is shown implemented as a moldable non-metallic wire, which is continuously or discontinuously woven into the fenestration area 122 with the wire of the covered membrane, i.e. the entire fenestration area (121) with the internally concave skeleton (122) becomes internally concave plastic and can expand, distinguishing it from other areas as a feature of the covered membrane. [Figure 4A] A stent graft (100) is shown having a first stent graft segment (110) having a framework consisting of a proximal end main body stent (111) and a proximal end access graft (112), and a third stent graft segment (130) having a framework consisting of a distal end main body stent (131) and a distal end access stent (132). [Figure 4B] The overlying stent graft (100) is shown partially expanded outward, reducing the distance between the arterial opening and the fenestrated area of the superior cerebral aneurysm (121). [Figure 5A] A stent graft (100) is shown in which a first stent graft segment (110) comprises a main stent (111) located outside the covered membrane and partially engaging with the covered membrane, and an internal stent (113) located inside the covered membrane and fully engaging with the covered membrane, and a second stent graft segment (120) comprises a fenestration region (121), and the fenestration region (121) does not include a skeleton. [Figure 5B]The stent graft (100) is shown with the temporary inflow access (140) open and being collapsed into a predetermined shape in a controlled manner. [Figure 5C] The above stent graft (100) is shown having at least one stitch loop (144) on the same side of the temporary inflow access (140) and at least one stitch loop (144) on the opposite side, and at least one control line (145) for opening and closing the temporary inflow access (140) of the covered membrane, wherein the control line (145) is first passed sequentially from the distal end to the proximal end with a handle, passing through the stitch loops (144) on the opposite side of one or more temporary inflow accesses (140), then the control line (145) passes through the stitch loops (144) on the same side of one or more temporary inflow accesses (140) from the proximal end to the distal end, and finally the control line (145) then passes sequentially through the stitch loops (144) on the opposite side of one or more temporary inflow accesses (140) from the proximal end to the distal end. [Figure 6] Shown is a bare stent (200) consisting of a first bare stent segment (210), a second bare stent segment (220), and a third bare stent segment (230), which correspond to the first stent graft segment (110), the second stent graft segment (120), and the third stent graft segment (130), respectively. [Figure 7] The grid function is shown by setting the bare stent (200) so that the frame portion of the stent graft (100) is hooked onto it. [Figure 8A] This indicates the presence of one or more proximal end dissection hiats in the arch, with true and false lumens formed through the proximal end hiats. [Figure 8B] A clad stent (100) with temporary inflow access is implanted by transcatheter means, and the dissection hiatus is closed by the clad stent (100), but various branch vessels in the arch can still pass through the temporary inflow access (140) and receive normal blood perfusion. [Figure 8C]1 shows stent graft fenestration via a vascular pathway to the fenestration region (121) of the stent graft (100) where the fenestration region (121) does not have a metal frame or the inner recess frame is of a non-metallic material. [Figure 8D] A further implanted branch stent graft (100) is shown, with a fenestrated region (121) of the stent graft (100) without a metal frame. [Figure 8E] After the bare stent (200) is implanted using the transcatheter method, the proximal end access (141) and distal end access (143) stent frames are opened, and the fenestration area access (142) is also opened, showing that the covered membrane is attached to the blood vessel wall by the bare stent (200). [Figure 8F] The bare stent (200) is shown releasing from the proximal access (141) and distal access (143) when the stent graft is deployed. [Figure 8G] Figure 8F shows the situation with an implanted branch stent graft, with the bare stent (200) affixed tightly to the proximal flared end of the branch stent graft in the fenestration area (121). [Figure 9A] The stent graft (100) has a temporary inflow access with a fenestrated area having an inwardly recessed feature located at the end of the stent graft (100), i.e., includes only a first stent graft segment (110) and a second stent graft segment (120) with a fenestrated area, and accordingly, the temporary inflow access (140) includes a non-fenestrated access (141) and a fenestrated access (142). [Figure 9B] Temporary inflow access (140) is shown consisting of fenestration access (142) only. [Figure 9C] A temporary inflow access (140) is shown emanating from the fenestration area (121) and extending into but not through the first stent graft segment (110). [Figure 10A] Descending aortic dissection involving the left subclavian artery. [Figure 10B]1 shows a stent graft (100) with temporary inflow access implanted by transcatheter means, where the dissection hiatus is closed by the stent graft and the ends of the stent graft are fenestrated with internal concave features. [Figure 10C] A stent graft (100) is shown implanted and then fenestrated through a vascular pathway into the fenestrated area. [Figure 10D] A stent graft (100) is implanted and routed through the vascular pathway to the fenestration area, after which a branch stent graft is implanted in the left subclavian artery. [Figure 10E] The bare stent (200) is shown implanted by transcatheter technique, the temporary inflow access (140) is opened by the bare stent, and the covered membrane is affixed to the vessel wall by the bare stent (200). [Figure 10F] A case with a branched stent graft implanted in the left subclavian artery is shown. [Figure 11A] Shown is an abdominal aortic aneurysm adjacent to the renal arteries. [Figure 11B] A stent graft (100) with two temporary inflow accesses is shown, implanted by transcatheter means. [Figure 11C] Following implantation of the stent graft (100), the stent graft fenestration in the fenestrated area is shown via the vascular pathway. [Figure 11D] Shown is the implantation of a stent graft (100) and fenestration of the stent graft via the vascular route, followed by further implantation of branch stent grafts into the left and right renal arteries. [Figure 11E] The bare stent (200) is shown implanted by catheterization, the temporary inflow access (140) is opened by the bare stent, and the membrane thereon is affixed to the vessel wall by the bare stent (200). [Figure 11F] Shown are the left and right renal arteries with implanted branched stent grafts. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention provides a vascular reconstruction device comprising a stent graft, in one embodiment, the stent graft comprising a body consisting of a frame and a covered membrane, the body comprising a fenestration area, the fenestration area comprising only the covered membrane, the surface of the stent graft comprising at least one temporary inflow access, the temporary inflow access communicating with the fenestration area.

[0011] In one embodiment, the temporary inflow access is projectable so that the stent graft is fixed in a circular cross section.

[0012] In one embodiment, the device further comprises a plurality of fenestration areas, each fenestration area being separated by an internal concave skeleton.

[0013] In one embodiment, the concave skeleton may or may not be connected to the frame of the body.

[0014] In one embodiment, the temporary inflow access is characterized by a cross section that is wider in communication with the fenestration area than in other sections.

[0015] In one embodiment, the window opening area is located at an end of the body and comprises an inwardly recessed feature.

[0016] In one embodiment, the body comprises a first stent graft segment, a second stent graft segment, and a third stent graft segment, and the fenestration region is disposed in the second stent graft segment. In one embodiment, the temporary inflow access is connected to the fenestration region of the second stent graft via the first stent graft segment or the third stent graft segment. In one embodiment, the second stent graft segment is more flexible than the first stent graft or the third stent graft segment.

[0017] In one embodiment, the configuration of the stent graft is partially outwardly or inwardly concave, straight, tapered or curved.

[0018] In one embodiment, said temporary inflow accesses are distributed on the surface of the stent graft in a linear fashion along the length of the stent graft, in a spiral fashion along the surface of the stent graft, or in any curved trajectory.

[0019] In one embodiment, the temporary inflow access is connected to at least one end of the stent graft.

[0020] In one embodiment, the stent graft comprises a control mechanism for controlling the opening and closing of the at least one temporary inflow access. In another embodiment, the control mechanism is disposed in a portion of the stent graft having the at least one temporary inflow access, wherein the frame and the covered membrane constituting the at least one temporary inflow access are not joined, the at least one temporary inflow access has at least one stitch loop on the same side and on the opposite side, and the covered membrane has at least one control line for opening and closing the temporary inflow access.

[0021] In one embodiment, the stent graft comprises internal stitch loops and control lines, and the temporary inflow access comprises a covered membrane with a controllable shape. In one embodiment, the shape of the temporary inflow access formed by the stent graft and covered membrane is controllable. In a further embodiment, the stent graft has a circular cross section.

[0022] The present invention further provides a vascular reconstruction device, in one embodiment comprising a stent graft as described herein and an expansion member, the expansion member being positionable within the stent graft for expansion to a diameter no less than an inner diameter of the stent graft.

[0023] In one embodiment, the expansion member is a bare stent. In one embodiment, the bare stent includes an area corresponding to the fenestration opening, the area being characterized by a sparse grid.

[0024] In one embodiment, the inflation member is a balloon.

[0025] The present invention further provides a method of using the vascular reconstruction device of the present invention, in one embodiment, the method comprising the steps of: a) placing the stent graft into a blood vessel in need thereof via a catheter, the blood vessel including at least one branch vessel; b) placing a temporary inflow access at the fenestration area outside the branch vessel to supply blood to the branch vessel; c) applying a stent graft fenestration to the fenestration area corresponding to the location of the branch vessel; and d) inserting the expansion member into the stent graft via the catheter and tensioning it until the cross section of the stent graft is fixed in a circular shape and fits against the inner wall of the blood vessel.

[0026] In one embodiment, step (c) further comprises implanting a branch stent graft at said location into the corresponding branch vessel. In one embodiment, the proximal end of the branch stent graft comprises a flare, and the expansion member of step (d) affixes the flare to the covered membrane of the fenestration area.

[0027] In one embodiment, the expansion member is a bare stent. In one embodiment, the bare stent comprises an area corresponding to the fenestration opening, the area being characterized by a sparse grid.

[0028] In one embodiment, the inflation member is a balloon.

[0029] In one embodiment, the expansion member withdraws the blood vessel after completing step (d).

[0030] In one embodiment, step (b) further comprises using a control mechanism to open the temporary inflow access. In another embodiment, the control mechanism comprises a control line, a stitch loop, a non-bonded frame, and a covered membrane, and pulling the control line opens the temporary inflow access. [Example]

[0031] In one embodiment, the present invention is an aortic reconstruction device comprising a stent graft (100) with temporary inflow access and one bare stent (200), in which a body consisting of a stent frame and a covered membrane thereover is composed of a first stent graft segment (110) (the end of the clad stent closest to the heart, hereafter referred to as the proximal end), a second stent graft segment (120), and a third stent graft segment (130) (the end of the stent graft farther from the heart, hereafter referred to as the distal end), where the second stent graft segment comprises a fenestration region (121). The surface of the stent graft (100) includes at least one temporary inflow access (140), and may further include a proximal end access (141), a fenestration region access (142), and a distal end access (143). The proximal access (141) is located in the first stent-graft segment (110), the fenestration region access (142) is included in the fenestration region (121), and the distal access (143) is located in the third stent-graft segment (130). The fenestration region (121) corresponds to one or more adjacent branch artery openings. The temporary inflow access (140) serves to allow blood to flow to the adjacent branch arteries through the temporary inflow access (140) when the stent-graft (100) is implanted in a blood vessel, preventing the stent-graft from impeding blood perfusion when it closes the branch artery opening during intraoperative fenestration. When the intraoperative fenestration of the fenestration region (121) is complete, or when an additional branch stent-graft is placed in the branch artery, the temporary inflow access (140) can be opened and converted into a concave shape to form a complete tubular shape with the stent-graft (100).

[0032] As shown in Figure 1B, the temporary inflow access (140) (consisting of the proximal access (141), fenestration access (142), and distal access (143)) can be formed into a cylindrical shape with the body of the stent graft when opened, as long as the cross section is of any shape, such as an arc, groove, V, or straight line, i.e., a partial circle. Preferably, the temporary inflow access (140) is a partial circular recess with a circular cross section, i.e., a circular recess formed by expanding the circumference without changing the circumference to form a full circle, as shown in Figure 1C.

[0033] In one embodiment, the temporary inflow access (140) may be distributed throughout the length of the stent graft (linear), or may be distributed throughout the surface of the stent graft in a spiral or any other curved trajectory to avoid possible intima entrapment within the vessel and occlusion of the temporary inflow access, as shown in FIG. 1D. [Example]

[0034] In one embodiment, optionally, the temporary inflow access (140) may not penetrate completely along its length, i.e., the temporary inflow access (140) may begin at the first stent graft segment (110), proximal end, and extend through the second stent graft segment (120) and end, or continue through but not penetrate, the third stent graft segment (130), as shown in FIG. 2A; or the temporary inflow access (140) may begin at the third stent graft segment (130), i.e., distal end, and extend through the second stent graft segment (120) and end, or continue through but not penetrate, the first stent graft segment (110), as shown in FIG. 2B.

[0035] In one embodiment, the three sections, temporary inflow access (140), proximal end access (141), fenestration region access (142), and distal end access (143), may be configured with the same or different cross-sectional shapes and the same or different access cross-sectional areas, preferably with the cross-sectional width of the fenestration region access (142) being greater than the cross-sectional widths of the proximal end access (141) and distal end access (143). Similarly, each section of the access (proximal end access (141), fenestration region access (142), distal end access (143)) may itself be configured with a uniform or graduated cross-section.

[0036] In one embodiment, the second stent graft segment (120) comprises one or more fenestrated regions (121).

[0037] In one embodiment, the fenestration areas (121) do not have a metal frame area, but comprise only covered membrane material, and adjacent fenestration areas (121) are spaced apart by an internally concave skeleton (122).

[0038] In one embodiment, the second stent graft segment is comprised of only fenestration regions, where an internal concave skeleton may not be present. The function of the internal concave skeleton (122) is to allow the stack of fenestration regions (121) to form and maintain an internal concave access configuration. The configuration of the internal concave skeleton (122) may be an internal concave circular structure, an internal concave wavy structure, an internal concave multiple V-shaped structure, etc. The internal concave skeleton (122) may or may not be attached to the stent body of the second stent graft segment (120).

[0039] In one embodiment, the material of the concave skeleton (122) may be a metallic material such as stainless steel wire, nickel-titanium alloy wire, or a moldable non-metallic material such as nylon or polytetrafluoroethylene, preferably a non-metallic material that can be broken by a laser or other window processing. [Example]

[0040] In one embodiment, the internally concave skeleton (122) may be connected to the covered membrane of the fenestration region (121) via stitches at one or more stitch points, as shown in Figure 3A. Optionally, the internally concave skeleton (122) may be realized as a ribbon structure within the fenestration region (121) woven together with the covered membrane, as shown in Figure 3B. Optionally, the internally concave skeleton (122) may also be implemented as a moldable non-metallic wire, which is continuously or discontinuously woven together with the stent wire in the fenestration region (121), i.e., the entire fenestration region (121) with the internally concave skeleton (122) may be realized as an internally concave plastic, which may be expanded separately from the other regions of the stent feature, as shown in Figure 3C. The purpose of providing the fenestration area with only a covered membrane without a metal frame and providing a sparse internal concave skeleton (122) or an internal concave skeleton (122) made of a non-metallic material is to minimize interference with the metal frame during fenestration and improve the success rate of fenestration and subsequent branch stent graft placement. Preferably, the circumferential width of the fenestration area (121) is larger than the diameter of the branch artery to ensure sufficient space for alignment between the fenestration area and the branch artery and to facilitate alignment between the branch artery and the fenestration area. For example, the circumferential width of the fenestration area (121) may be in the range of 0.5 cm to 5 cm in the application area of the aortic arch.

[0041] The first stent graft segment (110) and the third stent graft segment (130) primarily function as intraoperative anchors for the overlapping stent. A certain degree of flexibility is necessary to allow the stent to adapt to the specific anatomical structure of the lesion (e.g., aneurysms with torsional angles, arcuate lesions, etc.). As described above, the individual segments of the stent graft can be configured to have the same or different radial support. Preferably, the first stent graft segment (110) and the third stent graft segment (130) have greater support than the second stent graft segment (120) and are more flexible than the other two segments. When the stent body is a wavy linear body, the above-mentioned differentiated stents can be achieved by changing the wire diameter, design dimensions of the wavy structure, or density of the wavy structure. For example, when the stent body is a cut-and-formed type, the length, width, and angle of each section can be varied. For example, when the stent body is a woven stent, the density of the fabric can be varied. Optionally, each of the three stent graft segments can be implemented with a different process, such as wavy frame construction, braided, cut, or 3D printed, to achieve differentiated performance results for each segment. [Example]

[0042] As described above for the stent graft (100), the framework of the first stent graft segment (110) consists of a proximal end body stent (111) and a proximal end access stent (112), while the framework of the third stent graft segment (130) consists of a distal end body stent (131) and a distal end access stent (132), as shown in Figure 4A. The proximal end body stent (111) and the proximal end access stent (112) may have the same or different stiffnesses, and similarly, the distal end body stent (131) and the distal end access stent (132) may have the same or different stiffnesses. To allow the proximal end access stent (112) and the distal end access stent (132) to be easily erected by subsequent implantation of a bare stent or an expansion mechanism such as a balloon, the proximal end access stent (112) preferably has lower stiffness than the main body stent (111) in the same segment, and the distal end access stent (132) preferably has lower stiffness than the main body stent (131) in the same segment. The proximal end access bracket (112) may or may not be connected to the proximal end main body bracket (111), and both of these may be selected from the same or different structural units, the same or different materials, and manufacturing processes, and the distal end access stent (132) may or may not be connected to the distal end main body stent (131), and both of these may be selected from the same or different structural units, the same or different materials.

[0043] The material of the main stent frame of the above-mentioned stent graft (100) can be stainless steel, or nickel-titanium alloy, or cobalt-chromium alloy, optionally in the form of a wire or tube.

[0044] The body of the stent graft (100) as described above may be a straight cylinder of uniform diameter, a graduated cone, or a curved shape to suit the anatomy of the application site.

[0045] In one embodiment, the stent graft (100) as described above may be partially outwardly expanded and optionally partially inwardly recessed to facilitate application when the aneurysm contains branch arteries, i.e., to reduce the distance between the branch artery opening and the opening (121) on the aneurysm, as in Figure 4B, to facilitate opening and subsequent implantation of a potential branch stent graft.

[0046] The stent graft (100) as described above preferably has a diameter at its proximal and distal ends that is no smaller than the diameter of the corresponding vessel at the implantation site.

[0047] The stent graft (100) as described above may have a covered membrane disposed on the outer surface of the holder frame structure, on the inner surface, or on both the inner and outer surfaces of the holder frame structure. Optionally, the covered membrane material may be polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), silicone, etc.

[0048] If the stent graft (100) does not have temporary inflow access at its distal end, optionally the membrane covering the distal end may extend beyond the body of the stent to form a stentless skirt portion to facilitate possible future re-surgical procedures. [Example]

[0049] In one embodiment, the stent graft (100) has a circular cross section, and the temporary inflow access (140) is comprised of a covered membrane with a controlled shape. As shown in Figures 5A and 5B, the first stent graft segment (110) comprises a main stent (111) located outside the covered membrane and partially engaging with it, and an internal stent (113) located inside the covered membrane and fully engaging it, and the second stent graft segment (120) comprises a fenestration region (121), which does not include a skeleton, so that the first stent graft segment (110) and the second stent graft segment (120) are movable and can function as the temporary inflow access (140) when collapsed.

[0050] In one embodiment, as shown in Figure 5C, at least one stitch loop (144) is provided on each of the same side and opposite side of the temporary inflow access (140) at the proximal end of the covered membrane, and at least one control line (145) is provided to open and close the temporary inflow access (140) of the covered membrane, where the control line (145) is first passed through one or more temporary inflow accesses in sequence from the distal end to the proximal end with the handle, and on the opposite side of the temporary inflow access (140) from the stitch loop (144) of the temporary inflow access (140), the control line (145) passes through the stitch loop (144) on the same side of the one or more temporary inflow accesses (140) from the proximal end to the distal end, and finally, the control line (145) passes through the stitch loop (144) on the opposite side of the one or more temporary inflow accesses (140) in sequence from the proximal end to the distal end. 5B and 5C, stitch loops 144 are provided on the midline and opposite sides of the temporary inflow access 140, respectively, so that withdrawal of the control lines 145 opens the temporary inflow access 140 and allows the stent graft 100 to bend about the x-axis. It will be appreciated that multiple control lines 145 and corresponding stitch loops 144 may be provided circumferentially around the stent graft 100, providing greater control over the configuration of the temporary inflow access 140 and allowing the stent graft 100 to be rotated about the x-, y-, and z-axes, respectively, in the illustrated coordinate system, enhancing its ability to adhere to the wall in curved vessels and ameliorating the problems of "bird's beak" and "endoleak."

[0051] In one embodiment, the stent graft (100) is positioned within the target vessel with the fenestration region (121) corresponding to the branch vessel, at which point the operator pulls both ends of the control line (145) at the distal end of the handle, fully opening the temporary inflow access (140). At the same time, increasing the amount of pulling causes the stent graft (100) to collapse into a predetermined shape until it is in close contact with the vessel wall. Conversely, when the control line (145) is released, the repulsive force of the proximal internal stent (113) automatically closes the temporary inflow access (140). Once the fenestration is complete and the branch stent is implanted, the operator can completely withdraw the control line (145) from the main body with the handle by continuously pulling one of the ends of the control line (145) at the distal end of the handle.

[0052] After placing the above-mentioned stent graft (100) in the aorta, a fenestration operation corresponding to the branch artery is performed in the fenestration area, or a branch stent graft is further placed in the branch artery through the fenestration area, and then the bare stent is re-placed to return the temporary inflow access to the tubular shape of the stent graft body, thereby expanding the temporary inflow access.

[0053] The bare stent (200) described above is comprised of a first stent graft segment (210), a second stent graft segment (220) and a third stent graft segment (230), which correspond to the first stent graft segment (110), the second stent graft segment (120) and the third stent graft segment (130), respectively, as shown in Figure 6.

[0054] As described above, the bare stent (200) has a diameter dimension larger than the inner diameter of the stent graft (100), thereby reliably opening the temporary inflow access (140) located in the stent graft (100), ensuring its own secure fixation to the stent graft (100), and also ensuring that the branch stent graft in the fenestration region (121) is tightly adhered to the covering membrane, reducing the risk of internal leakage.

[0055] In one embodiment, the main body of the bare stent (200) as described above is implemented as an internal stent in a cut and expanded form, a braided stent, or a hybrid cut and braided process. The bare stent material can be any filament or tube, such as stainless steel, nickel-titanium memory alloy, or cobalt-chromium alloy.

[0056] In one embodiment, optionally as described above, the bare stent (200) comprises a first bare stent segment (210) and a third bare stent segment (230) having greater radial support than the second bare stent segment (220), and optionally the second bare stent segment (220) has better flexibility compared to the first bare stent segment (210) and the third bare stent segment (230). All of the aforementioned characteristics can be achieved by configuring various parameters, such as grid density, section rod width, and filament diameter.

[0057] In one embodiment, optionally, as described above, the bare stent (200) has a sparser grid in the area corresponding to the fenestration area (121) of the stent graft (100) compared to other areas so that blood perfusion in the branch arteries after fenestration is not affected by the bare stent.

[0058] In one embodiment, similar to the stent graft (100) described above, the bare stent (200) may have a right cylindrical body of equal diameter, a tapered shape with a narrowing diameter, or a partially convex or concave internal contour configuration.

[0059] In one embodiment, optionally, the bare stent (200) can hold the stent graft (100) while comprising one or more anchoring mechanisms for the stent graft, which can be achieved by mutual snap-restriction between the frame structures of the two stents, such as the snap-restriction profile shown in Figure 7. This can be achieved by configuring the grid features of the bare stent (200) so that the frame portion of the stent graft (100) can hook onto them; for example, if the frame structure of the stent graft (100) is wavy cells, the bare stent (200) can also have similar wavy cells at local locations, and the two can be matched to form a snap-anchor mechanism.

[0060] Optionally, depending on the anatomical and treatment strategy needs, the length of the bare stent (200) may be greater than, equal to, or less than the length of the stent graft (100) as described above.

[0061] Optionally, the bare stent (200) may be provided with a partially covered membrane on the outside of the area corresponding to the fenestration area (121) of the stent graft, for example, the first bare stent segment (210) and the third bare stent segment (310).

[0062] Optionally, the distal end of the bare stent (200) may be provided with a covered membrane, extending beyond the bare stent frame to facilitate possible future revision surgery.

[0063] Optionally, the material of the covering membrane may be polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), silicone, etc. [Example]

[0064] The implantation process of the above-described stent graft (100) in the case of aortic arch encirclement is carried out as follows.

[0065] In one embodiment, as in Figure 8A, true and false lumens are formed within and originating from one or more proximal end dissecting hiats.

[0066] As shown in Figure 8B, a stent graft (100) with temporary inflow access is implanted by transcatheter means, and the dissection hiatus is closed by the stent graft (100), but the various branch vessels of the arch can still pass through the temporary inflow access (140) and receive normal blood perfusion.

[0067] Next, as shown in Figure 8C, the fenestration area is stent-grafted through the vascular pathway, and the fenestration area (121) of the stent-graft (100) can be without a metal frame or the concave frame can be made of a non-metallic material to avoid interference between the metal frame and the fenestration. Alternatively, as shown in Figure 8D, further implantation of the branch stent-graft (100) can be performed with the fenestration area (121) of the stent-graft (100) having no metal frame, again ensuring smooth implantation and deployment of the branch stent-graft.

[0068] As shown in Figure 8E, the bare stent (200) is implanted transcatheterically with the proximal access (141) and distal access (143) stent frames open, and with the fenestration area access (142) also open, the bare stent (200) affixes the stent graft to the vessel wall. In the case of a branch stent graft (100) implanted as shown in Figure 8F, the bare stent (200) allows the proximal end flare of the branch stent graft to fit into the fenestration area (121) cladding while keeping the proximal access (141) and distal access (143) open, ensuring no endoleaks as shown in Figure 8G.

[0069] If the main stent frame (including the temporary inflow access stent frame) is made from cut-to-size stainless steel or cobalt-chromium alloy tubing, as described above for the stent graft (100), an alternative implantation process can be performed in which the branch stent graft is implanted into the branch artery via a catheter after fenestration of the fenestration region (121) is complete, followed by balloon inflation, which expands the temporary inflow access into a cylindrical shape and its permanent shape. At this point, the bare stent (200) is not used, and only the stent graft (100) and the branch stent graft are permanently deployed. [Example]

[0070] A stent graft (100) having a temporary inflow access and a fenestration region with an internal concave feature as described above may be placed at the end of a stent and applied in necessary treatment situations, such as treating a descending aortic lesion involving the left subclavian artery or an abdominal aortic lesion involving the renal arteries. As shown in Figure 9A, the fenestration region (121) is located at the end of the stent graft (100) to which it belongs, i.e., it consists only of the first stent graft segment (110) and the second stent graft segment (120) having the fenestration region. Accordingly, the temporary inflow access (140) consists of a non-fenestration access (141) and a fenestration region access (142). Optionally, as shown in Figure 9B, the temporary inflow access (140) may consist only of the fenestration region access (142). Alternatively, as shown in Figure 9C, the temporary inflow access (140) may originate from the fenestration region (121) and extend to, but not through, the first stent graft segment (110).

[0071] Examples of descending aortic dissection involving the left subclavian artery include transplant surgery such as:

[0072] As shown in Figure 10A, this is a descending aortic dissection involving the left subclavian artery.

[0073] As shown in Figure 10B, a stent graft (100) with temporary inflow access is implanted by transcatheter means. The dissection hiatus is closed by the stent graft, and the end of the stent graft has an open, concave feature that allows normal blood perfusion to the left subclavian artery through the temporary inflow access (140).

[0074] As shown in Figure 10C, a stent graft is then fenestrated through the vascular route in the fenestration region, and the fenestration region (121) of the stent graft (100) is free of a metal frame or the internal concave frame is made of a non-metallic material to prevent interference with the fenestration. Alternatively, as shown in Figure 10D, a branch stent graft is further placed in the left subclavian artery. Furthermore, because there is no metal frame in the terminal fenestration region (121) of the stent graft (100), branch stent graft placement and stent deployment can be performed smoothly.

[0075] As shown in Figure 10E, a bare stent (200) is placed transcatheterically, opening the temporary inflow access (140) and affixing the membrane covered by the bare stent (200) to the vessel wall. In the case of the left subclavian artery with a branch stent graft implanted as shown in Figure 10F, a bare stent can optionally be placed at the proximal end of the length of the stent graft. Similarly, the bare stent (200) holds the temporary inflow access open while affixing the flared proximal end of the branch stent graft to the covering of the fenestration area to prevent endoleaks. [Example]

[0076] As an example, the grafting process for an abdominal aortic aneurysm involving the renal arteries is as follows:

[0077] As shown in Figure 11A, the abdominal aortic aneurysm is close to the renal arteries.

[0078] As shown in Figure 11B, a stent graft (100) with two temporary inflow accesses is implanted via a transcatheter approach. The ends of the stent graft have openings with concave features, allowing the left and right renal arteries to pass through the temporary inflow accesses (140) to achieve normal blood perfusion.

[0079] As shown in Figure 11C, a stent graft is then fenestrated in the fenestration area via the vascular route, and the fenestration area (121) of the stent graft (100) is free of a metal frame or the internal concave frame is made of a non-metallic material to prevent interference with the fenestration. Alternatively, as shown in Figure 11D, a branch stent graft is further placed in the left subclavian artery. Furthermore, because there is no metal frame in the terminal fenestration area (121) of the stent graft (100), branch stent graft placement and stent deployment can be performed smoothly.

[0080] As shown in Figure 11E, a bare stent (200) is implanted transcatheterically, the temporary inflow access (140) is held open by the bare stent, and the covered membrane is affixed to the vessel wall by the bare stent (200). When branch stent grafts are placed in the left and right renal arteries, as shown in Figure 11F, the bare stent (200) affixes the flared proximal end of the branch stent graft to the covered membrane in the fenestration area, preventing endoleaks, while holding the temporary inflow access open.

[0081] The above implementation process is exemplified by the arch and is equally applicable to other portions of the aorta and similar vascular situations, and the above implementation process is exemplified by aortic dissection and is equally applicable to aortic aneurysms and similar vascular situations.

Claims

1. 1. A vascular reconstruction device comprising:

1. A stent graft comprising a body consisting of a frame and a covered membrane, the body has a fenestration area, the fenestration area being an area comprised solely of the membrane where a fenestration will be formed during a surgical procedure; a stent graft, wherein the membrane has at least one temporary inflow access on its surface, the temporary inflow access communicating with the fenestration area; at least one branch stent graft having a flared proximal end and implanted in the fenestration area; a bare stent disposed within the stent graft and expanded to a diameter not smaller than the inner diameter of the stent graft, the bare stent affixing the flare to the fenestration area; 12. A vascular reconstruction device comprising:

2. The vascular reconstruction device of claim 1 , wherein the bare stent includes an area corresponding to the fenestration area, the area having a sparse grid.

3. The vascular reconstruction device of claim 1 , wherein the temporary inflow access is expandable such that the cross section of the stent graft is fixed in a circular shape.

4. The vascular reconstruction device of claim 1 , further comprising a plurality of fenestration regions each separated by an internal concave skeleton.

5. The vascular reconstruction device according to claim 4, wherein the internal concave skeleton is connected or not connected to the frame of the main body.

6. The vascular reconstruction device of claim 1, wherein the temporary inflow access has a cross section that is wider at the portion that communicates with the fenestration area than at other portions.

7. The vascular reconstruction device of claim 1 , wherein the fenestration area is located at an end of the body and has an inwardly recessed feature.

8. The vascular reconstruction device of claim 1, wherein the body comprises a first stent graft segment, a second stent graft segment and a third stent graft segment, and the fenestration region is located in the second stent graft segment.

9. 9. The vascular reconstruction device of claim 8, wherein the temporary inflow access is connected to the fenestration region of the second stent graft segment via the first stent graft segment or the third stent graft segment.

10. The vascular reconstruction device of claim 8 , wherein the second stent graft segment is more flexible than the first stent graft segment or the third stent graft segment.

11. The vascular reconstruction device of claim 1 , wherein the stent graft has a configuration that is partially outwardly bulging or inwardly concave, right cylindrical, tapered, or curved.

12. The vascular reconstruction device of claim 1, wherein the temporary inflow access is distributed on the surface of the stent graft in a linear fashion along the length of the stent graft, in a spiral fashion along the surface of the stent graft, or in any curved trajectory.

13. 13. The vascular reconstruction device of claim 1 or 12, wherein the temporary inflow access is connected to at least one end of the stent graft.

14. 13. The vascular reconstruction device according to claim 1 or 12, characterized in that it comprises a control mechanism for controlling the opening and closing of said at least one temporary inflow access.

15. 15. The vascular reconstruction device of claim 14, wherein the control mechanism is disposed in a portion of the stent graft having at least one temporary inflow access, the frame and the covered membrane constituting the at least one temporary inflow access are not joined, there is at least one stitch loop on each of the same side and opposite side of the at least one temporary inflow access on the inner surface of the stent graft, and at least one control line is provided for opening and closing the temporary inflow access of the covered membrane.

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