stent graft

Abstract

To suppress inconveniences due to projection of an end stent from a graft.SOLUTION: A stent graft includes: a cylindrical graft 12; and an end stent 14 connected to an end in an axial direction of at least the graft 12. The end stent 14 is provided with a hook part 16 hung for restraint of expansion of the end stent 14 over a stent restraint mechanism of a delivery device. The hook part 16 can shorten projection length of a part projecting outside in an axial direction from an end in the axial direction of the graft 12 by the axial direction end of the graft 12 expanding together with the end stent 14. A variable range of projection length of the hook part 16 may include zero.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to stent grafts. [Background technology]

[0002] Patent Document 1 discloses a stent graft comprising a tubular graft and an end stent connected to at least the axial end of the graft. A delivery device such as that described in Patent Document 1 is used to deliver this stent graft to a target position in a luminal organ. The delivery device comprises a cover that covers the stent graft to restrict the expansion of the entire graft, and a stent restraining mechanism onto which the end stent is hooked to restrict the expansion of the end stent. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2019-510579 Summary of the Invention [Problem to be solved by the invention]

[0004] To hook an end stent onto the stent restraint mechanism, a hook portion that forms part of the end stent must protrude from the axial end of the graft. When the end stent is expanded together with the axial end of the graft by releasing the restraint by the stent restraint mechanism, the protruding length of the hook portion of the end stent typically remains constant. With this structure, when the stent graft is attached to the luminal organ by expanding the graft, problems are likely to occur due to the protrusion of the end stent from the graft. The present inventors newly recognized the existence of such problems and came up with the stent graft of the present disclosure.

[0005] One object of the present disclosure is to provide a stent graft that can suppress defects caused by the protrusion of an end stent from the graft. [Means for solving the problem]

[0006] The stent graft of the present disclosure comprises a tubular graft and an end stent connected to at least the axial end of the graft, the end stent having a hook portion that can be hooked onto a stent restraining mechanism of a delivery device to restrain the expansion of the end stent, and the hook portion can shorten the protruding length of the part that protrudes axially outward from the axial end by expanding the axial end together with the end stent. [Effects of the Invention]

[0007] According to the present disclosure, problems caused by the protrusion of the end stent from the graft can be suppressed. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1(A) is a first schematic diagram for explaining the effect of the stent graft of the present disclosure, and FIG. 1(B) is a second schematic diagram thereof. [Figure 2] FIG. 1(A) is a first schematic diagram for explaining another effect of the stent graft of the present disclosure, and FIG. 1(B) is a second schematic diagram thereof. [Figure 3] FIG. 1 is a schematic perspective view of a delivery device according to a first embodiment. [Figure 4] FIG. 2 is a schematic cross-sectional side view of the stent graft and its surroundings in the delivery device of the first embodiment. [Figure 5] FIG. 10 is a first explanatory view relating to the operation of the delivery device of the first embodiment. [Figure 6] FIG. 10 is a second explanatory view relating to the operation of the delivery device of the first embodiment. [Figure 7] FIG. 1 is a side view schematically showing a stent graft of a first embodiment. [Figure 8]FIG. 2 is another side view schematically showing the stent graft of the first embodiment. [Figure 9] FIG. 9(A) is a development view that shows a schematic view of a part of the stent graft of the first embodiment, and FIG. 9(B) is a view in which the sutures are omitted from FIG. 9(A). [Figure 10] 9(A) and the surrounding structure. FIG. [Figure 11] FIG. 11(A) is a diagram showing a schematic view of the movable projection portion of FIG. 10, and FIG. 11(B) is a diagram showing its operation. [Figure 12] FIG. 10 is a development view showing a schematic view of a portion of a stent graft of a second embodiment. [Figure 13] FIG. 13(A) is a development view that schematically shows a part of the stent graft of the third embodiment, and FIG. 13(B) is a view showing its operation. [Figure 14] FIG. 14(A) is a development view that shows a schematic view of a part of the stent graft of the third embodiment, and FIG. 14(B) is a view in which the sutures are omitted from FIG. 14(A). DETAILED DESCRIPTION OF THE INVENTION

[0009] (First embodiment) Hereinafter, an embodiment for implementing the stent graft of the present disclosure will be described. The same or equivalent elements will be given the same reference numerals, and duplicate explanations will be omitted. In each drawing, for the sake of convenience, components will be omitted, enlarged, or reduced as appropriate. The drawings should be viewed in accordance with the orientation of the reference numerals.

[0010] First, the background that led to the conception of the stent graft of the present disclosure will be explained. In a delivery device, it is desirable for the graft to be constrained by the cover in a state in which it is contracted as uniformly as possible in the circumferential direction. This is advantageous for properly positioning the stent graft at the target position within the luminal organ and for smoothly expanding the stent graft. To achieve this, it is desirable to contract the axial end of the graft together with the end stent as uniformly as possible in the circumferential direction by hooking the end stent onto the stent restraining mechanism of the delivery device. To hook the end stent onto the stent restraining mechanism, multiple hook portions of the end stent must protrude from the axial end of the graft.

[0011] As mentioned above, when the axial end of the graft expands from a contracted state by releasing the restraint by the stent restraint mechanism, if the protruding length of the hook portion of the end stent remains constant, it is likely to cause problems due to the end stent protruding from the graft.

[0012] For example, consider the case in which an end stent 14 is placed inside a graft 12, as shown in Figure 1(A). In this case, when the stent graft 10 is attached to a luminal organ 20, the longer the protruding length L of the hook portion 16 of the end stent 14, the smaller the contact area between the graft 12 and the end stent 14. This can easily lead to a problem in which the graft 12 has difficulty dispersing the expansive force at the protruding portion of the end stent 14 protruding from the graft 12.

[0013] 2(A), consider the case where an end stent 14 is placed on the outside of the graft 12. In this case, when the stent graft 10 is attached to a luminal organ 20, the longer the protruding length L of the end stent 14, the more likely it is that bodily fluids will penetrate over a wide area onto the outside of the graft 12 via the protruding portion of the end stent 14 protruding from the graft 12. This can easily lead to a problem in which the adhesion of the graft 12 to the luminal organ 20 decreases.

[0014] To address this issue, the hooks 16 of the stent graft of the present disclosure are capable of changing their protrusion length L in conjunction with the expansion or contraction of the axial end of the graft 12 together with the end stent 14, and are characterized in that the expansion of the axial end of the graft 12 shortens the protrusion length L. This allows the protrusion length L of the hooks 16 to be shortened when the axial end 12a of the graft 12 expands due to the release of the restraint by the stent restraint mechanism. In other words, the protrusion length L of the hooks 16 when the stent graft 10 is attached to the luminal organ 20 can be shortened compared to the protrusion length L of the hooks 16 when restrained by the stent restraint mechanism. Consequently, problems caused by the hooks 16 of the end stent 14 protruding from the graft 12 when the stent graft 10 is attached to the luminal organ 20 can be suppressed compared to when the protrusion length L does not change before and after the release of the restraint by the stent restraint mechanism.

[0015] For example, consider the case where an end stent 14 is placed inside a graft 12, as shown in Figure 1(B). In this case, the shorter the protruding length L of the hook portions 16 of the end stent 14, the larger the contact area between the graft 12 and the end stent 14. This prevents the problem of the expansion force of the hook portions 16 of the end stent 14 becoming difficult to distribute to the graft 12. In this way, the easier it is to distribute the expansion force of the end stent 14 to the graft 12, the more advantageous it is in that the burden on the luminal organ 20 can be reduced.

[0016] 2(B), consider the case where an end stent 14 is placed on the outside of the graft 12. In this case, the shorter the protruding length L of the hook portion 16 of the end stent 14, the more difficult it is for bodily fluids to enter via the inside of the protruding portion protruding from the graft 12. This in turn can prevent the problem of reduced adhesion of the graft 12 to the luminal organ 20.

[0017] Please refer to Figures 3 and 4. Next, we will explain the delivery device 100. For the sake of convenience of explanation, the stent graft 10 in Figure 4 has a different appearance from the stent graft 10 of the embodiment.

[0018] The delivery device 100 comprises a handle 102 that is held by the surgeon, and a shaft 104 that is passed through the stent graft 10 and supports the stent graft 10. In addition, the delivery device 100 comprises a cover 106 that covers the stent graft 10 to restrict the expansion of the entire graft 12, and a stent restraint mechanism 108 that restrains the expansion of the end stent 14 by hooking onto the multiple hook portions 16 of the end stent 14. In addition, the delivery device 100 of this embodiment comprises an introducer sheath 110 that is connected to the handle 102.

[0019] The cover 106 is passed through the introducer sheath 110 and can be pulled in the axial direction by the surgeon's operation using a first operating mechanism (not shown). The entire graft 12 tends to expand together with at least one stent, including the end stent 14 of the stent graft 10. The cover 106 restrains the expansion of the entire graft 12 by the stent.

[0020] The stent restraint mechanism 108 is provided separately from the cover 106. The stent restraint mechanism 108 includes a plurality of stent receiving portions 108a onto which the plurality of hooking portions 16 of the end stent 14 are hooked. The plurality of stent receiving portions 108a are axially extending rod-shaped, and the hooking portions 16 of the end stent 14 are hooked along their radially inner sides. When the hooking portions 16 of the end stent 14 are hooked onto the plurality of stent receiving portions 108a, the expansion of the end stent 14 is restrained, and the expansion of the axial end 12a of the graft 12 is also restrained. The plurality of stent receiving portions 108a can be moved axially by the surgeon using a second operating mechanism (not shown). The stent restraint mechanism 108 can switch between restraining and not restraining the end stent 14 by axially moving each stent receiving portion 108a.

[0021] An example of a method for placing the stent graft 10 using the delivery device 100 will be described. First, while the graft 12 is constrained in a contracted state by the delivery device 100, the stent graft 10 is transported together with the delivery device 100 to the target position in the luminal organ. Next, as shown in FIG. 5, the cover 106 is pulled by the first operating mechanism, thereby releasing the constraint of the graft 12 by the cover 106. Thereafter, as shown in FIG. 6, the stent receiving portions 108a of the stent constraint mechanism 108 are moved axially by the second operating mechanism, thereby releasing the hooking of the end stent 14 by the stent constraint mechanism 108 and releasing the constraint of the end stent 14 by the stent constraint mechanism 108. As a result, the graft 12 expands from the contracted state, and the stent graft 10 is attached at the target position in the luminal organ.

[0022] Reference will be made to Figures 7 and 8. Next, the stent graft 10 will be described. Figure 7 schematically shows the graft 12 of the stent graft 10 in a maximum expanded state (described later), and Figure 8 schematically shows the graft 12 in a reference contracted state (described later). In this specification, the direction along the center line of the graft 12 is referred to as the axial direction, and the radial and circumferential directions about that center line are simply referred to as the radial and circumferential directions. Also, in this specification, the terms "outside" and "inside" are sometimes used to refer to the axial outer and inner sides of the graft 12. Here, the "outside" in the axial direction refers to the side away from the axial center position of the graft 12, and the "inside" in the axial direction refers to the side approaching that axial center position.

[0023] The stent graft 10 is placed in a luminal organ in the body to treat vascular dissection, aneurysms, and obstruction of the digestive tract. Here, the luminal organ refers to, for example, a blood vessel or the digestive tract. The stent graft 10 comprises a tubular graft 12 and an end stent 14 connected to at least the axial end 12a of the graft 12. The stent graft 10 may also comprise another stent connected axially inward of the end stent 14. Alternatively, the end stent 14 may extend to the axial center of the graft 12. In this embodiment, the end stent 14 is positioned inside the graft 12, but it may also be positioned outside it.

[0024] The graft 12 is a flexible tubular member. The graft 12 expands together with the end stents 14 and maintains a state of being attached to the inside of the luminal organ 20, thereby forming a flow path for bodily fluids inside the graft 12. The graft 12 is made of, for example, a knitted or woven fabric using resin fibers, metal fibers, or the like.

[0025] The end stent 14 can expand radially outward together with the graft 12 by self-expansion. Here, "self-expansion" refers to expansion by the restoring force associated with its own elastic deformation. The end stent 14 is made of wire made of metals such as shape memory alloys and stainless steel, as well as resins, etc. Hereinafter, the state in which no external force is applied to contract the graft 12 and end stent 14 and the axial end 12a of the graft 12 and end stent 14 are expanded by the self-expansion force of the end stent 14 until the outer diameter of the graft 12 reaches its maximum is referred to as the "maximum expanded state."

[0026] The end stent 14 has a plurality of hooks 16 that can be hooked onto the stent restraint mechanism 108 of the delivery device 100 to restrain the expansion of the end stent 14. In this embodiment, the hooks 16 are shaped to be convex outward in the axial direction of the graft 12 and folded back in the axial direction. The plurality of hooks 16 are arranged circumferentially on the end stent 14. Although only two hooks 16 are shown schematically here, the number is not particularly limited and may be either one or three or more.

[0027] When the axial end 12a of the graft 12 expands or contracts together with the end stent 14, the multiple hooks 16 can change the protruding length L of their portions protruding axially outward from the axial end 12a of the graft 12 in response to the expansion or contraction. The configuration for achieving this will be described later. Here, the protruding length L refers to the axial length from the axially outer end of the hook 16 of the end stent 14 to the axial end of the graft 12, which is located at the same circumferential position as the axially outer end. Figure 7 shows an example in which the protruding length L is zero. When the hook 16 protrudes from the axial end 12a of the graft 12, the protruding portion of the hook 16 can be hooked onto the stent receiving portion 108a of the stent restraint mechanism 108. At this time, the protruding portion of the hook 16 forms an opening that penetrates the radial direction of the graft 12 between the axial end 12a of the graft 12 and the hook 16. The stent receiving portion 108a of the stent restraining mechanism 108 is passed through the opening formed by the hook portion 16, whereby the hook portion 16 is hooked onto the stent receiving portion 108a.

[0028] The multiple hooks 16 can shorten the protruding length L by expanding the axial end 12a of the graft 12. The protruding length L of the hooks 16 can gradually shorten by expanding the axial end 12a of the graft 12 until it reaches the lower limit of the variable range of the protruding length L. This variable range of the protruding length L includes zero. It can also be said that the variable range of the protruding length L has zero as its lower limit. After the protruding length L is set to zero, the hooks 16 can gradually retract axially inward from the axial end of the end stent 14 by expanding the axial end 12a of the graft 12 until it reaches its maximum expanded state. Alternatively, the protruding length L of the multiple hooks 16 may become zero when it reaches its maximum expanded state.

[0029] The effects of the above-described stent graft 10 will now be described. As described above, the protrusion length L of the hooking portions 16 of the stent graft 10 can be shortened by expanding the graft 12 together with the end stent 14. Therefore, as described above, by shortening the protrusion length L of the hooking portions 16 when attaching the stent graft 10 to the luminal organ 20, problems caused by the protrusion of the end stent 14 can be suppressed. Furthermore, when attaching the end stent 14 to the stent restraint mechanism 108, by increasing the protrusion length L of the hooking portions 16, the attachability of the end stent 14 to the stent restraint mechanism 108 can be improved.

[0030] Furthermore, the variable range of the protrusion length L of the end stent 14 includes zero. Therefore, compared to when the variable range of the protrusion length L exceeds zero, the protrusion length L of the end stent 14 when attaching the stent graft 10 to the luminal organ 20 can be made as short as possible. Consequently, the effect of suppressing problems caused by the protrusion of the end stent 14 can be effectively achieved.

[0031] Next, other features of the stent graft 10 will be described. The maximum and average protrusion lengths of the hook portions 16 will be considered. When the end stent 14 has only a single hook portion 16, the protrusion length L of that single hook portion 16 becomes the maximum protrusion length and the average protrusion length. When the end stent 14 has multiple hook portions 16, the maximum of the protrusion lengths L of the multiple hook portions 16 becomes the maximum protrusion length, and the simple average of these protrusion lengths becomes the average protrusion length. In this case, the stent graft 10 can shorten both the maximum and average protrusion lengths of the hook portions 16 by expanding the graft 12, and it can be said that the variable ranges of these lengths include zero.

[0032] The outer diameter of the axial end 12a of the graft 12 when the graft 12 is in the maximum expanded state is referred to as Rm. In this specification, outer diameter refers to diameter. The state in which the outer diameter of the axial end 12a of the graft 12 has contracted to 50% of the outer diameter Rm in the maximum expanded state is referred to as the reference contracted state. The state in which the outer diameter of the axial end 12a of the graft 12 is Rm × 50% is the reference contracted state. In this reference contracted state, the contracted portion of the axial end 12a of the graft 12 extends straight along the axial direction.

[0033] The maximum protruding length L1 of the hook portion 16 when the graft 12 is in a standard contracted state is preferably 1 mm or more. By satisfying this condition, the protruding length of the hook portion 16 can be made appropriately long when attaching the end stent 14 to the stent restraint mechanism 108, improving the attachability of the end stent 14 to the stent restraint mechanism 108. The upper limit of the maximum protruding length L1 of the hook portion 16 is not particularly limited, but may be, for example, 10 mm.

[0034] The maximum protrusion length L0 of the hook portion 16 when the graft 12 is in the maximum expanded state is preferably 5 mm or less. This allows the protrusion length of the hook portion 16 to be appropriately short when attaching the stent graft 10 to the luminal organ 20, and effectively suppresses problems caused by the protrusion of the end stent 14.

[0035] When the end stent 14 is shortened from the maximum protrusion length L1 in the standard contracted state to the maximum protrusion length L0 in the maximally expanded state, the ratio of the shortening of the maximum protrusion length to the maximum protrusion length L1 is called the shortening rate (%). The shortening rate is expressed by the following formula (1) and varies within the range of more than zero and not more than 100. When the maximum protrusion length L0 of the end stent 14 in the maximally expanded state is zero, the shortening rate reaches its maximum value (100%). Shortening rate (%) = {(L1-L0) / L1} × 100 (1)

[0036] The shortening rate is preferably 50% or more. This allows the protruding length of the end stent 14 to be relatively appropriately long when the end stent 14 is attached to the stent restraint mechanism 108, and allows the protruding length of the end stent 14 to be relatively appropriately short when the stent graft 10 is attached to the luminal organ 20. This in turn improves the attachability of the end stent 14 to the stent restraint mechanism 108, while effectively suppressing problems caused by the protrusion of the end stent 14.

[0037] Measurement of parameters related to the stent graft 10 (outer diameter of the graft 12, protruding length of the end stent 14) will now be described. To measure these parameters and bring the graft 12 to a reference contracted state, a cable tie 22 may be wrapped around the axial end 12a of the graft 12, and the cable tie 22 may be used to uniformly contract the graft 12 over its entire circumference. The outer diameter of the axial end 12a of the graft 12 may be the maximum value measured over the entire circumference using a non-contact outer diameter measuring device. When bringing the graft 12 to a reference contracted state using the cable tie 22, the cable tie 22 may be made of a light-transmitting material, and the outer diameter at the point where the cable tie 22 is wrapped may be measured using a diameter measuring device that uses laser light.

[0038] As described above, when evaluating the parameters (maximum protrusion length L1, shortening rate) when the graft 12 is in the reference contraction state, the reference lower limit and upper limit are referred to as the reference lower limit and reference upper limit, respectively. For the maximum protrusion length L1, the reference lower limit is 1 mm, and the reference upper limit is 10 mm. For the shortening rate, the reference lower limit is 50%. To determine whether the condition that a parameter in this reference contraction state is equal to or greater than the reference upper limit is satisfied, a reference contraction state in which the outer diameter of the graft 12 is Rm × 50% may be actually achieved. In this case, for example, if the measured value of the maximum protrusion length L1 in the reference contraction state is equal to or greater than the reference lower limit (1 mm), it is determined that the condition that the maximum protrusion length L1 is equal to or greater than the reference lower limit is satisfied. Alternatively, for ease of measurement, the outer diameter of the graft 12 may be set to a value close to Rm × 50%, as follows, and then the condition for that parameter may be determined to be satisfied.

[0039] As the outer diameter of the axial end 12a of the graft 12 decreases, the maximum protrusion length L1 of the hook portion 16 increases and the shortening rate increases. As the outer diameter increases, the maximum protrusion length L1 of the hook portion 16 decreases and the shortening rate decreases. Consider a case where the outer diameter of the graft 12 is within a range of more than 50% but not exceeding 60% of the outer diameter Rm and as close to 50% of the outer diameter Rm as possible. In this case, if the measured value of the maximum protrusion length L1 is equal to or greater than the reference lower limit (here, 1 mm), the maximum protrusion length L1 in the reference contraction state at 50% of the outer diameter Rm will also be equal to or greater than the reference lower limit (because L1 increases as the outer diameter of the graft 12 decreases). Similarly, if the measured value of the shortening rate is equal to or greater than the reference lower limit (here, 50%), the shortening rate in the reference contraction state at 50% of the outer diameter Rm will also be equal to or greater than the reference lower limit. Based on this, when the outer diameter of the graft 12 is within the range of more than 50% but not exceeding 60% of the outer diameter Rm and is as close as possible to 50% of the outer diameter Rm, if the measured value of the maximum protrusion length L1 or shortening rate is equal to or greater than the standard lower limit value, it may be determined that the maximum protrusion length L1 or shortening rate in the standard contracted state is also equal to or greater than the standard lower limit value.

[0040] Consider also the case where the outer diameter of the graft 12 is within a range of 40% or more but less than 50% of the outer diameter Rm and as close to 50% of the outer diameter Rm as possible. In this case, if the measured value of the maximum protrusion length L1 of the hook portion 16 is equal to or less than the upper reference limit (here, 10 mm), the maximum protrusion length L1 in a standard contracted state, which is 50% of the outer diameter, will also be equal to or less than the upper reference limit (because L1 becomes shorter as the outer diameter of the graft 12 increases). Based on this, if the measured value of the maximum protrusion length L1 in a range of 40% or more but less than 50% of the outer diameter Rm and as close to 50% of the outer diameter Rm as possible is equal to or less than the upper reference limit, it may be determined that the maximum protrusion length L1 in a standard contracted state is also equal to or less than the upper reference limit.

[0041] Please refer to Figures 9(A) and 9(B). Figure 9(A) is a development view showing a part of the shape of the stent graft 10 after cutting open a part of it in the axial direction and developing it into a plane. The dashed lines in Figure 9(A) indicate sutures 42A and 42B.

[0042] The terminal stent 14 has a plurality of ridges 30A, 30B that are arranged circumferentially and convex outward in the axial direction of the graft 12. In this embodiment, all of the ridges 30A, 30B contact each other, forming an outer zigzag pattern 32 that extends in a zigzag pattern in the axial direction toward the circumferential direction. In this embodiment, the outer zigzag pattern 32 is continuous in an annular shape. Note that circumferentially adjacent ridges 30A, 30B may be separated from each other.

[0043] The multiple peaks 30A, 30B are formed by at least one wavy portion 34 that forms a wave shape that meanders in the axial direction and extends in the circumferential direction. In this embodiment, the multiple peaks 30A, 30B are formed by multiple (specifically, three) wavy portions 34. In this embodiment, the multiple wavy portions 34 form wave shapes with the same wavelength but different phases from each other. In this embodiment, an example is shown in which the multiple wavy portions 34 are formed by a single wire that repeatedly wraps around the graft 12, but they may also be formed by separate wires. The waves formed by the wavy portion 34 are not particularly limited as long as they have a shape that meanders in the axial direction and extends in the circumferential direction. Here, an example is shown in which the wavy portion 34 forms a triangular wave shape, but various wave shapes (e.g., rectangular wave shape, etc.) that are used in the end stent 14 may also be formed.

[0044] The multiple peaks 30A, 30B include at least one movable peak 30A and at least one fixed peak 30B. In this embodiment, the movable peaks 30A and the fixed peaks 30B are alternately arranged in the circumferential direction, but the arrangement order is not particularly limited. As described below, the movable peak 30A is allowed to move relative to the graft 12 in the axial direction at least at the peak 30Aa, and forms the hook 16 for hooking onto the stent restraint mechanism 108. The fixed peak 30B is connected to the graft 12 by a connecting member 44, which will be described below, and is fixed to the graft 12 so as to be immovable relative to the axial and circumferential directions. Here, relative movement refers to relative movement between the two entities (e.g., the graft 12 and the peak 30Aa of the movable peak 30A).

[0045] The end stent 14 of this embodiment has a plurality of valleys 36 that are convex toward the axial inside of the graft 12 and are arranged in the circumferential direction. The plurality of valleys 36 are formed by at least one (three in this case) wavy portion 34 described above. In this embodiment, all of the valleys 36 contact each other with adjacent valleys 36, thereby forming an inner zigzag pattern 38 that extends in a zigzag pattern in the axial direction toward the circumferential direction. In this embodiment, the inner zigzag pattern 38 is continuous in an annular shape.

[0046] 9(A), 9(B), and 10. The end stent 14 has a plurality of fixing portions 40 that are provided contiguous to the movable peaks 30A on both circumferential sides of the movable peaks 30A and are fixed to the graft 12. In this embodiment, the fixing portions 40 are provided at locations including the crests 36a of the valleys 36 of the wavy portions 34. For each movable peak 30A, there is a pair of fixing portions 40 corresponding to one movable peak 30A. In this embodiment, the fixing portions 40 corresponding to one movable peak 30A are not common to the fixing portions 40 corresponding to the other movable peaks 30A, but they may be common to each other.

[0047] The fixing portions 40 are connected to the graft 12 by suturing, adhesive bonding, or the like, and are thereby fixed to the graft 12 so as to be immovable relative to the graft 12 in the circumferential and axial directions. In this embodiment, the fixing portions 40 are connected to the graft 12 by suturing using a first suture 42A. In this embodiment, the first suture 42A is used to suturing a portion of the end stent 14 to the graft 12 along the inner zigzag pattern 38 described above, thereby fixing the multiple fixing portions 40 on the inner zigzag pattern 38 to the graft 12.

[0048] The movable convex portion 30A includes an apex 30Aa constituting the axially outer end of the movable convex portion 30A, and a pair of intermediate line portions 30Ab provided between the apex 30Aa and the fixed portion 40. The movable convex portion 30A is allowed to move axially relative to the graft 12 at least at the apex 30Aa. To achieve this, the stent graft 10 of this embodiment includes a connecting member 44 that connects the intermediate line portion 30Ab to the graft 12 axially inward of the apex 30Aa of the movable convex portion 30A so as to be movable relative to the graft 12 in the longitudinal direction of the intermediate line portion 30Ab. Here, the longitudinal direction refers to the direction in which the intermediate line portion 30Ab extends (axial direction). Alternatively, to achieve this, the movable convex portion 30A does not necessarily have to be connected to the graft 12 by suturing, adhesive, or the like.

[0049] The connecting member 44 of this embodiment connects each of the pair of intermediate line portions 30Ab on both circumferential sides of the apex 30Aa of the movable convex portion 30A to the graft 12. Alternatively, only one of the intermediate line portions 30Ab may be connected to the graft 12. The connecting member 44 of this embodiment is a second suture 42B. The second suture 42B is sewn to the graft 12 to form one loop 46 that sutures the intermediate line portion 30Ab to the graft 12. Here, the location of one loop 46 is indicated by a circle. The intermediate line portion 30Ab is sewn at one location (one loop 46) with the second suture 42B, so that it is connected to the graft 12 so as to be movable relative to the graft 12 in the longitudinal direction.

[0050] The second suture 42B is sewn to the graft 12 to form a first stitch portion 42Ba extending along the fixed mountain portion 30B and a second stitch portion 42Bb extending between the intermediate line portions 30Ab of the pair of movable mountain portions 30A. Each stitch portion 42Ba, 42Bb has a plurality of stitches repeatedly arranged in a direction along the stitch portion 42Ba, 42Bb. The second suture 42B connects the plurality of fixed mountain portions 30B on the outer zigzag pattern 32 to the graft 12 via the first stitch portion 42Ba. The second suture 42B also connects the intermediate line portion 30Ab on the outer zigzag pattern 32 to the graft 12 via the aforementioned stitch portion 46 provided at the end of the second stitch portion 42Bb.

[0051] The fixed crest 30B is connected to the graft 12 by suturing, adhesive bonding, or the like, and is thereby fixed to the graft 12 so as not to move relative to the graft 12 in the axial and circumferential directions. The fixed crest 30B of this embodiment is connected to the graft 12 by suturing with the first stitch portion 42Ba of the second suture 42B described above. The fixed crest 30B of this embodiment is connected to the graft 12 over an axial range including its apex. The fixed crest 30B of this embodiment is connected to the graft 12 axially outward of the connection point (location of the eyelet 46) of the movable crest 30A by the connecting member 44.

[0052] The effects of the stent graft 10 described above will now be explained. Reference is made to Figures 11(A) and 11(B). As described above, the end stent 14 includes a pair of fixing portions 40 that are provided contiguous to the movable peak 30A on both circumferential sides of the movable peak 30A and are fixed to the graft 12. Therefore, when the graft 12 contracts, the pair of fixing portions 40 corresponding to the movable peak 30A of the end stent 14 along with the graft 12 also move in direction D1 so as to shorten the circumferential distance between them. As a result, the shorter the circumferential distance between the pair of fixing portions 40, the more the apex 30Aa of the movable peak 30A located between the pair of fixing portions 40 moves relative to the graft 12 in direction D2 toward the axial outward direction. Accordingly, the protruding length L of the movable peak 30A that protrudes axially outward from the axial end of the graft 12 can be increased.

[0053] Furthermore, when the graft 12 expands, the pair of fixing portions 40 of the end stent 14 move together with the graft 12 so that the circumferential distance between them increases. As a result, the longer the circumferential distance between the pair of fixing portions 40, the more the apex 30Aa of the movable convex portion 30A moves axially inward relative to the graft 12. Accordingly, the protruding length L of the movable convex portion 30A protruding axially outward from the axial end of the graft 12 can be shortened.

[0054] That is, by relatively moving the apex 30Aa of the movable convex portion 30A in the axial direction in conjunction with the expansion and contraction of the graft 12, it is possible to change the protruding length L of the movable convex portion 30A relative to the axial end portion 12a of the graft 12. In other words, by adopting such a configuration, the movable convex portion 30A is configured as a hook portion 16 whose protruding length relative to the axial end portion 12a of the graft 12 is adjustable.

[0055] The stent graft 10 includes a connecting member 44 that connects the intermediate line portion 30Ab of the movable mountain portion 30A to the graft 12 so that the intermediate line portion 30Ab can move relative to the graft 12 in the longitudinal direction. Therefore, when the top 30Aa of the movable mountain portion 30A attempts to move axially relative to the graft 12, the relative position of the movable mountain portion 30A to the graft 12 can be maintained at the connection point (circled in the figure) by the connecting member 44 while allowing the intermediate line portion 30Ab to move relative to the graft 12 in the longitudinal direction. For example, consider a case where the pair of fixing portions 40 corresponding to the movable mountain portion 30A moves in direction D1. In this case, the intermediate line portion 30Ab can move in direction D3 along the longitudinal direction relative to the graft 12 at the connection point by the connecting member 44, preventing the entire movable mountain portion 30A from being significantly tilted relative to the axial direction. Therefore, the top 30Aa of the movable convex portion 30A can be moved relative to the graft 12 along the axial direction as much as possible, and the protruding length L of the movable convex portion 30A can be stably changed in conjunction with the expansion and contraction of the graft 12.

[0056] The multiple peaks 30A, 30B include fixed peaks 30B fixed to the graft 12 in addition to movable peaks 30A whose protruding length relative to the graft 12 can be changed. Therefore, compared to when the multiple peaks are composed only of movable peaks 30A, the range over which the axial end 12a of the graft 12 is connected to the end stent 14 can be made wider. In particular, by connecting the fixed peaks 30B axially outward from the connection points of the movable peaks 30A, the axial range over which the axial end 12a of the graft 12 is connected to the end stent 14 can be made wider axially outward compared to when there are no fixed peaks 30B. Consequently, curling of the end at the axial end 12a of the graft 12 can be suppressed.

[0057] In addition, the variable range of the protruding length L of the movable mountain portion 30A may be adjusted by adjusting (1) the circumferential distance between the pair of fixed portions 40 connected to the movable mountain portion 30A, and (2) the angle relative to the axial direction of the line segment connecting the top 30Aa of the movable mountain portion 30A and the fixed portion 40. For example, the variable range of the protruding length of the movable mountain portion 30A can be increased by increasing the circumferential distance (1) or the angle (2).

[0058] (Second embodiment) See Fig. 12. In the following embodiments, among the components described in the first embodiment, the same content as in the first embodiment is applied to the components that are not described below.

[0059] In the above-described embodiment, an example was described in which the multiple peaks of the end stent 14 are alternately arranged as movable peaks 30A and fixed peaks 30B. In this embodiment, all of the multiple peaks are movable peaks 30A. As such, the multiple peaks do not necessarily include fixed peaks 30B. Similarly to the first embodiment, the multiple movable peaks 30A of this embodiment are connected to the graft 12 at each pair of intermediate line portions 30Ab by a connecting member 44 made of a second suture 42B. Unlike the first embodiment, the second suture 42B is sewn to the graft 12 so as to form only the second stitch portion 42Bb. In this embodiment, the same effects as the first embodiment can be obtained, except for the features related to the fixed peaks 30B.

[0060] (Third embodiment) Please refer to Figures 13(A), 13(B), 14(A) and 14(B). Figure 13(A) is a view in which sutures 42A and 42B are omitted from Figure 14(A).

[0061] Similar to the first embodiment, the multiple peaks 30A, 30B of this embodiment include movable peaks 30A and fixed peaks 30B, which are alternately arranged in the circumferential direction. In this embodiment, the multiple wavy portions 34A, 34B forming the peaks 30A, 30B include a first wavy portion 34A and a second wavy portion 34B having a wavy shape with a second wavelength λ2 that is longer than the first wavelength λ1 of the waves of the first wavy portion 34A. In this embodiment, there are two second wavy portions 34B having the same wavelength but with a phase difference of ½ of that wavelength. While an example is shown in which the two second wavy portions 34B are formed by a single wire that repeatedly wraps around the graft 12, they may also be formed by separate wires.

[0062] In addition to the multiple wavy portions 34A, 34B that form the peaks 30A, 30B, the terminal stent 14 also has an inner wavy portion 50 that has a wave shape with the same wavelength as the first wavy portion 34A. The inner wavy portion 50 is out of phase with the first wavy portion 34A by half the wavelength. The valleys of the first wavy portion 34A and the peaks of the inner wavy portion 50 form hook portions 52 that hook onto each other. In Figures 14(A) and 14(B), the locations of the hook portions 52 are indicated by square symbols.

[0063] The peaks 34Aa of the first wavy portion 34A are disposed between the peaks 34Ba of the second wavy portion 34B adjacent in the circumferential direction and are in contact with the peaks 34Ba, so that the peaks 34Aa of the first wavy portion 34A and the peaks 34Ba of the second wavy portion 34B form an outer zigzag pattern 32 that extends in a zigzag pattern in the circumferential direction.

[0064] The valleys 50b of the inner wavy portion 50 are arranged between the valleys 34Bb of the second wavy portions 34B that are adjacent in the circumferential direction, and are in contact with the valleys 34Bb. As a result, the valleys 34Bb of the second wavy portions 34B of the end stent 14 and the valleys 50b of the inner wavy portion 50 form an inner zigzag pattern 38 that extends zigzag in the circumferential direction.

[0065] To satisfy the aforementioned condition that the first wavelength λ1 of the first wavy portion 34A is smaller than the second wavelength λ2 of the second wavy portion 34B, the minimum wavelength of each wave in the second wavy portion 34B must be longer than the maximum wavelength of each wave in the first wavy portion 34A. In this embodiment, the second wavelength λ2 is an integer multiple (here, for example, twice) of the first wavelength λ1, but it may be any other value. To satisfy this condition, the first average wavelength is defined as the simple average of the wavelengths of each wave in the first wavy portion 34A, and the second average wavelength is defined as the simple average of the wavelengths of each wave in the second wavy portion 34B. The second average wavelength must be within a ±10% range of the integer multiple of the first average wavelength. Note that the specific relationship between the first wavelength λ1 and the second wavelength λ2 is not particularly limited to the content of the embodiment.

[0066] In this embodiment, the second wavy portion 34B has a wave shape with a second amplitude W2 that is greater than the first amplitude W1 of the waves of the first wavy portion 34A. To satisfy this condition, it is sufficient that the minimum amplitude of each wave in the second wavy portion 34B is greater than the maximum amplitude of each wave in the first wavy portion 34A. In this embodiment, the second amplitude W2 is an integer multiple (here, as an example, twice) of the first amplitude W1, but it may be any other amplitude. To satisfy this condition, when the average value of the amplitudes of each wave in the first wavy portion 34A is defined as the first average amplitude and the average value of the amplitudes of each wave in the second wavy portion 34B is defined as the second average amplitude, it is sufficient that the second average amplitude is within a range of ±10% of an integer multiple of the first average amplitude. The first wavelength λ1 < the second wavelength λ2 does not necessarily have to be a specific magnitude relationship between the first amplitude W1 and the second amplitude W2.

[0067] In this embodiment, the movable peaks 30A are formed by the peaks 34Ba of the second wavy portion 34B, and the fixed peaks 30B are formed by the peaks 34Aa of the first wavy portion 34A. The multiple fixed portions 40 continuous with the movable peaks 30A of the end stent 14 are provided in the valleys 34Bb of the second wavy portion 34B. To achieve this, as described above, a portion of the end stent 14 is sutured to the graft 12 along the inner zigzag pattern 38 with the first suture 42A, thereby fixing the multiple fixed portions 40 on the inner zigzag pattern 38 to the graft 12. At this time, the valleys 50b of the inner wavy portion 50 on the inner zigzag pattern 38 are also fixed to the graft 12.

[0068] When the protrusion length is changed by moving the apex 30Aa of the movable convex portion 30A relative to the graft 12 in the axial direction, as described above, increasing the circumferential distance between the pair of fixing portions 40 connected to the movable convex portion 30A is advantageous in increasing the variable range of the protrusion length. Increasing the circumferential distance between the pair of fixing portions 40 is effective, for example, by increasing the wavelength of the waves formed by the wavy portion. In this embodiment, the movable convex portion 30A is provided on the second wavy portion 34B, which has a wavy shape with a second wavelength λ2 that is longer than the first wavelength λ1. Therefore, compared to when the second wavelength λ2 is the same as the first wavelength λ1, this is advantageous in increasing the variable range of the protrusion length of the movable convex portion 30A (hook portion 16).

[0069] In the first embodiment, an example was described in which the valleys 36 between circumferentially adjacent fixing peaks 30B in one wavy portion are fixed to the graft 12. In contrast, in the present embodiment, the valleys 36 (in this embodiment, the locations where the hook portions 52 are formed) between circumferentially adjacent fixing peaks 30B in the first wavy portion 34A are not connected to the graft 12 by sewing, adhesive, or the like, and are allowed to move relative to the graft 12 in the axial and circumferential directions. The advantages of this will be explained below.

[0070] When the graft 12 attempts to contract, it moves so that the circumferential distance between circumferentially adjacent fixed peaks 30B becomes shorter. As a result, the valleys 36 between the fixed peaks 30B attempt to move axially inward relative to the graft 12. At this time, if the valleys 36 are fixed to the graft 12, a resistance force F acting axially outward from the fixed point acts on the wavy portion 34A, making it difficult to contract the graft 12 due to the influence of this resistance force F. In contrast, if the valleys 36 between the fixed peaks 30B are allowed to move relative to the graft 12, as in this embodiment, the resistance force F does not act on the valleys 36 when the graft 12 attempts to contract. Consequently, even if the multiple peaks 30A, 30B include fixed peaks 30B, it is possible to contract the graft 12 with a lighter force. Additionally, this embodiment can achieve the same effects as the stent graft 10 of the first embodiment.

[0071] Variations of the above components will now be described.

[0072] The delivery device 100 of the embodiment is merely an example. While the example has been described in which the stent restraint mechanism 108 restrains the expansion of the distal end of the graft 12 together with the end stent 14, the stent restraint mechanism 108 may restrain the expansion of the proximal end of the graft 12 together with another end stent or a portion of the same stent. Furthermore, specific examples of each operating mechanism and the stent restraint mechanism 108 are not particularly limited. As in the embodiment, the multiple stent receiving portions 108a of the stent restraint mechanism 108 may be made of the same material, or may be made of different materials.

[0073] In the embodiment, an example has been described in which the conditions for the lower limit of the maximum protrusion length L1 and the upper limit of the maximum protrusion length L0 are simultaneously satisfied. However, this is not limiting, and only the condition for either L1 or L0 may be satisfied, or neither may be satisfied. Furthermore, the condition for the shortening rate may not be satisfied. Furthermore, the variable range of the protrusion length L of the graft 12 may be greater than zero, while satisfying the condition for either the shortening rate or the maximum protrusion length L1 or L0.

[0074] The specific configuration for changing the protruding length L of the hook portion 16 of the end stent 14 is not particularly limited.

[0075] The multiple peaks 30A, 30B of the end stent 14 do not have to be formed by the wavy portion 34. For example, the multiple peaks 30A, 30B may be provided at the ends of multiple spiral portions that extend spirally in the axial direction.

[0076] The stent graft 10 does not necessarily have to include the connecting member 44. The connecting member 44 that connects the intermediate line portion 30Ab of the movable stent graft 30A to the graft 12 may be a tubular member that is fixed to the graft 12 and through which the intermediate line portion 30Ab movably passes.

[0077] The above-described embodiments and variations are merely examples. The abstract technical concepts should not be interpreted as being limited to the contents of the embodiments and variations. Many design modifications are possible in the contents of the embodiments and variations, such as changing, adding, or deleting components. In the above-described embodiments, the term "embodiment" is used to emphasize the contents in which such design modifications are possible. However, design modifications are also permitted even in contents without such notation. Hatching on cross sections in the drawings does not limit the materials of the hatched objects. The structures and numerical values ​​referred to in the embodiments and variations naturally include those that can be considered identical when manufacturing errors are taken into account. [Explanation of symbols]

[0078] 10...Stent graft, 12...Graft, 14...End stent, 16...Hook portion, 30A...Movable ridge portion, 30Aa...Apex portion, 30Ab...Midline portion, 30B...Fixed ridge portion, 34, 34A, 34B...Wavy portion, 34A...First wavy portion, 34B...Second wavy portion, 40...Fixed portion, 44...Connecting member, 100...Delivery device, 108...Stent restraint mechanism.

Claims

1. A cylindrical graft and and an end stent connected to at least an axial end of the graft, The end stent is a hook portion that is hooked onto a stent restraining mechanism of a delivery device to restrain the expansion of the end stent; A movable convex portion that is convex outward in the axial direction of the graft; a plurality of fixing portions provided continuously with the movable convex portion on both circumferential sides of the movable convex portion and fixed to the graft; The hook portion can shorten the protruding length of the portion protruding axially outward from the axial end portion by expanding the axial end portion together with the end stent, the movable convex portion is allowed to move relative to the graft in the axial direction at least at its top, and constitutes the hook portion; The end stent has a plurality of peaks that are convex outward in the axial direction of the graft and are arranged in the circumferential direction of the graft, The plurality of peaks include the movable peaks and fixed peaks fixed to the graft.

2. the movable ridge portion includes a middle line portion provided between the top portion and the fixed portion, a connecting member that connects the intermediate line portion to the graft so as to be movable relative to the graft in the longitudinal direction of the intermediate line portion; The stent graft according to claim 1 , wherein the fixed crest is connected to the graft axially outside a connection point of the movable crest by the connecting member.

3. The plurality of peaks are formed by at least one wavy portion extending in a circumferential direction, The stent graft according to claim 1 , wherein the valleys between the fixed peaks adjacent in the circumferential direction in the wavy portion are allowed to move relative to the graft.

4. A cylindrical graft and and an end stent connected to at least an axial end of the graft, The end stent is a hook portion that is hooked onto a stent restraining mechanism of a delivery device to restrain the expansion of the end stent; A movable convex portion that is convex outward in the axial direction of the graft; a plurality of fixing portions provided continuously with the movable convex portion on both circumferential sides of the movable convex portion and fixed to the graft; The hook portion can shorten the protruding length of the portion protruding axially outward from the axial end portion by expanding the axial end portion together with the end stent, the movable convex portion is allowed to move relative to the graft in the axial direction at least at its top, and constitutes the hook portion; The end stent has a plurality of peaks arranged in a circumferential direction and projecting outward in the axial direction of the graft, The plurality of peaks are formed by at least a plurality of wavy portions extending in a circumferential direction, the plurality of wavy portions include a first wavy portion having a wavy shape of a first wavelength and a second wavy portion having a wavy shape of a second wavelength longer than the first wavelength, The stent graft wherein the movable ridge portion is constituted by the ridge portion of the second wavy portion.

5. A stent graft as described in claim 1 or 4, wherein the state in which the outer diameter of the axial end has contracted to 50% of the outer diameter Rm of the axial end when the graft is in the maximum expanded state is called the standard contracted state, and the maximum protrusion length L1 of the hook portion when the graft is in the standard contracted state is 1 mm or more.

6. 5. The stent graft according to claim 1, wherein the maximum protruding length L0 of the hook portion when the graft is in a maximum expanded state is 5 mm or less.

7. A stent graft as described in claim 1 or 4, wherein the state in which the outer diameter of the axial end has contracted to 50% of the outer diameter Rm of the axial end when the graft is in the maximum expanded state is called the reference contracted state, and the maximum protruding length of the hooking portion when the graft is in the reference contracted state is called L1, and the maximum protruding length of the hooking portion when the graft is in the maximum expanded state is called L0, and the shortening rate expressed by the following formula (1) is 50% or more. Shortening rate (%) = {(L1 - L0) / L1} × 100 (1)

8. 5. The stent graft according to claim 1, wherein the variable range of the protrusion length includes zero.

9. the movable ridge portion includes a middle line portion provided between the top portion and the fixed portion, 5. The stent graft according to claim 1, further comprising a connecting member that connects the intermediate line portion to the graft and is movable relative to the graft in the longitudinal direction of the intermediate line portion.

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