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 a stent graft. [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 as 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 on 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] In order to hook the end stent to the stent restraint mechanism, it is necessary to make the hook portion, which is a part of the end stent, 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 usually remains constant. With such a structure, when the stent graft is attached to a 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 restraint mechanism of a delivery device to restrain the expansion of the end stent, and the hook portion can shorten the protruding length of the portion protruding axially outward from the axial end by expanding the axial end together with the end stent. Effect of the Invention

[0007] According to the present disclosure, problems caused by the protrusion of an end stent from a graft can be suppressed. [Brief description 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. [Diagram 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. [Diagram 3] FIG. 1 is a schematic perspective view of a delivery device according to a first embodiment. [Figure 4] FIG. 2 is a schematic side cross-sectional view of the stent graft and its surroundings in the delivery device of the first embodiment. [Diagram 5] FIG. 4 is a first explanatory view relating to the operation of the delivery device of the first embodiment. [Figure 6] FIG. 11 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 showing a schematic view of a stent graft according to a first embodiment. [Figure 8]FIG. 2 is another side view showing typically the stent graft of the first embodiment. [Figure 9] FIG. 9(A) is a development view that shows a schematic view of a portion 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. 11A is a diagram showing a schematic diagram of the movable projection portion of FIG. 10, and FIG. 11B is a diagram showing its operation. [Figure 12] FIG. 11 is a development view showing a schematic view of a portion of a stent graft according to a second embodiment. [Figure 13] FIG. 13(A) is a development view that shows a schematic view of a portion of the stent graft of the third embodiment, and FIG. 13(B) is a view showing the operation thereof. [Figure 14] FIG. 14(A) is a development view that shows a schematic view of a portion of a 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 PREFERRED EMBODIMENTS

[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 duplicated explanations will be omitted. In each drawing, for the sake of convenience of explanation, components will be omitted, enlarged, or reduced as appropriate. The drawings should be viewed according to the orientation of the reference numerals.

[0010] First, the background that led to the stent graft of the present disclosure will be described. In the 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 in 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 to the stent restraining mechanism of the delivery device. In order to hook the end stent to the stent restraining mechanism, it is necessary for multiple hook portions of the end stent to 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] 1(A), consider the case where an end stent 14 is placed inside a 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 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 of 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 to the outside of the graft 12 through the protruding parts 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] As a countermeasure against this, the hook portion 16 of the stent graft of the present disclosure is characterized in that when the axial end portion of the graft 12 expands or contracts together with the end stent 14, the protruding length L can be changed in conjunction with the expansion or contraction of the axial end portion of the graft 12, and the protruding length L can be shortened by the expansion of the axial end portion of the graft 12. As a result, when the axial end portion 12a of the graft 12 expands due to the release of the restraint by the stent restraint mechanism, the protruding length L of the hook portion 16 can be shortened. In other words, the protruding length L of the hook portion 16 when the stent graft 10 is attached to the luminal organ 20 can be shortened compared to the protruding length L of the hook portion 16 when restrained by the stent restraint mechanism. In addition, compared to the case where the protruding length L does not change before and after the release of the restraint by the stent restraint mechanism, when the stent graft 10 is attached to the luminal organ 20, the problem caused by the hook portion 16 of the end stent 14 protruding from the graft 12 can be suppressed.

[0015] For example, consider the case where an end stent 14 is placed inside a graft 12, as shown in Fig. 1(B). In this case, the shorter the protruding length L of the hook portion 16 of the end stent 14 can be made, the larger the contact area between the graft 12 and the end stent 14. This makes it possible to suppress the problem that it becomes difficult to distribute the expansion force of the hook portion 16 of the end stent 14 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 can be made, the more difficult it becomes for bodily fluids to enter through the inside of the protruding portion protruding from the graft 12. This in turn makes it possible to suppress the problem of reduced adhesion of the graft 12 to the luminal organ 20.

[0017] Please refer to Figures 3 and 4. Next, a description will be given of the delivery device 100. For ease of explanation, the stent graft 10 in Figure 4 has an appearance different from that of the stent graft 10 in the embodiment.

[0018] The delivery device 100 comprises a handle 102 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 restraining mechanism 108 that restrains the expansion of the end stent 14 by hooking the multiple hook portions 16 of the end stent 14. In addition, the delivery device 100 of this embodiment comprises an introducer sheath 110 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 operation 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 restraining mechanism 108 is provided separately from the cover 106. The stent restraining mechanism 108 includes a plurality of stent receiving portions 108a to which the plurality of hook portions 16 of the end stent 14 are hooked. The plurality of stent receiving portions 108a are axially extending rod-shaped, and the hook portions 16 of the end stent 14 are hooked to pass through their radially inner sides. When the hook portions 16 of the end stent 14 are hooked to 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 in the axial direction by the operator using a second operating mechanism (not shown). The stent restraining mechanism 108 can switch between restraining the end stent 14 and not restraining it 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, the stent graft 10 is transported together with the delivery device 100 to a target position in a luminal organ while the graft 12 is restrained in a contracted state by the delivery device 100. Next, as shown in FIG. 5, the cover 106 is pulled by the first operating mechanism to release the restraint of the graft 12 by the cover 106. Thereafter, as shown in FIG. 6, the stent receiving portions 108a of the stent restraining mechanism 108 are moved in the axial direction by the second operating mechanism to release the hooking of the end stent 14 by the stent restraining mechanism 108, and the restraint of the end stent 14 by the stent restraining mechanism 108 is released. 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] Please refer to Figures 7 and 8. Next, the stent graft 10 will be described. Figure 7 shows a schematic diagram of the graft 12 of the stent graft 10 in a maximum expansion state (described later), and Figure 8 shows a schematic diagram of the graft 12 in a reference contraction 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 around the center line are simply referred to as the radial and circumferential directions. Also, in this specification, there are times when the terms "outside" and "inside" are used in the axial direction of the graft 12. The "outside" in the axial direction here 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 the axial center position.

[0023] The stent graft 10 is placed in a luminal organ in the body for the treatment of vascular dissection, aneurysm, and obstruction of the digestive tract. The luminal organ here refers to, for example, a blood vessel, a digestive tract, and the like. The stent graft 10 includes a tubular graft 12 and an end stent 14 connected to at least an axial end 12a of the graft 12. The stent graft 10 may include another stent connected axially inward of the end stent 14. In addition, the end stent 14 may extend to the axial center of the graft 12. The end stent 14 in this embodiment is disposed inside the graft 12, but may be disposed 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 tubular organ 20, thereby forming a flow path for the flow of bodily fluids inside the graft 12. The graft 12 is made of, for example, a knitted fabric or a 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 a restoring force accompanying its own elastic deformation. The end stent 14 is made of a wire material using 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 the graft 12 and the end stent 14 to contract, and the axial end 12a of the graft 12 and the end stent 14 are expanded by the self-expansion force of the end stent 14 until the outer diameter of the graft 12 becomes maximum, is referred to as the maximum expansion state.

[0026] The end stent 14 has a plurality of hooks 16 that can be hooked to the stent restraining 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 protrude outward in the axial direction of the graft 12 and to be folded back in the axial direction. The plurality of hooks 16 are arranged in the circumferential direction of the end stent 14. Although only two hooks 16 are shown 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 hooks 16 can change the protruding length L of the portion protruding axially outward from the axial end 12a of the graft 12 in conjunction with the expansion or contraction. A configuration for realizing this will be described later. The protruding length L here refers to the length along the axial direction from the axial outer end of the hook 16 of the end stent 14 to the axial end of the graft 12 at the same circumferential position as the axial outer end. FIG. 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 on the stent receiving portion 108a of the stent restraining 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 protruding length L of the hooks 16 can be shortened by the expansion of the axial end 12a of the graft 12. The protruding length L of the hooks 16 can be gradually shortened by the expansion of 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 the lower limit. After the protruding length L is set to zero, the hooks 16 can be gradually retracted axially inward from the axial end of the end stent 14 by the expansion of the axial end 12a of the graft 12 until it reaches the maximum expanded state. Alternatively, the protruding length L of the hooks 16 may become zero when it reaches the maximum expanded state.

[0029] The effects of the above stent graft 10 will now be described. As described above, the protruding length L of the hooking portion 16 of the stent graft 10 can be shortened by the expansion of the graft 12 together with the end stent 14. Therefore, as described above, by shortening the protruding length L of the hooking portion 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 restraining mechanism 108, the attachment of the end stent 14 to the stent restraining mechanism 108 can be improved by increasing the protruding length L of the hooking portion 16.

[0030] Furthermore, the variable range of the protruding length L of the end stent 14 includes zero. Therefore, compared with the case where the variable range of the protruding length L exceeds zero, the protruding length L of the end stent 14 when the stent graft 10 is attached to the luminal organ 20 can be made as short as possible. As a result, the effect of suppressing problems caused by the protrusion of the end stent 14 can be effectively obtained.

[0031] Next, other features of the stent graft 10 will be described. The maximum and average protruding lengths of the hooks 16 will be considered. When the end stent 14 has only a single hook 16, the protruding length L of the single hook 16 is the maximum protruding length and the average protruding length. When the end stent 14 has multiple hooks 16, the maximum of the protruding lengths L of the multiple hooks 16 is the maximum protruding length, and the simple average of these protruding lengths is the average protruding length. In this case, the stent graft 10 can shorten both the maximum and average protruding lengths of the hooks 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. A 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. A 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 at 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 appropriately long when attaching the end stent 14 to the stent restraint mechanism 108, improving the attachment 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 protruding 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 protruding 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 shortened 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 exceeding 100. When the maximum protrusion length L0 of the end stent 14 in the maximally expanded state is zero, the shortening rate is the 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, while allowing 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. As a result, the attachment of the end stent 14 to the stent restraint mechanism 108 can be improved, while the effect of suppressing problems caused by the protrusion of the end stent 14 can be favorably obtained.

[0037] Measurement of parameters related to the stent graft 10 (outer diameter of the graft 12, protruding length of the end stent 14) will be described. When measuring these parameters and bringing the graft 12 into 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 of the measurements taken over the entire circumference using a non-contact outer diameter measuring device. When bringing the graft 12 into 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 around may be measured using an outer diameter measuring device using laser light.

[0038] In evaluating the parameters (maximum protrusion length L1, shortening rate) when the graft 12 is in the reference contraction state as described above, the lower limit and upper limit are referred to as the reference lower limit and the reference upper limit, respectively. In the case of the maximum protrusion length L1, the reference lower limit is 1 mm, and the reference upper limit is 10 mm. In the case of the shortening rate, the reference lower limit is 50%. In determining whether or not the condition that the parameter in the reference contraction state is equal to or greater than the reference upper limit or equal to or less than the reference lower limit is satisfied, the reference contraction state in which the outer diameter of the graft 12 is Rm×50% may actually be realized. In this case, for example, when 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, in consideration of the convenience of measurement, the outer diameter of the graft 12 may be realized in a state close to Rm×50% as follows, and then the condition regarding the parameter may be determined to be satisfied.

[0039] The smaller the outer diameter of the axial end 12a of the graft 12, the longer the maximum protruding length L1 of the hook portion 16 and the larger the shortening rate, and the larger the outer diameter, the shorter the maximum protruding length L1 of the hook portion 16 and the smaller the shortening rate. Here, consider a case where the outer diameter of the graft 12 is within a range of more than 50% to 60% of the outer diameter Rm and is as close to 50% of the outer diameter Rm as possible. In this case, if the measured value of the maximum protruding length L1 is equal to or greater than the reference lower limit (here, 1 mm), the maximum protruding length L1 in the reference contraction state at 50% of the outer diameter Rm is also equal to or greater than the reference lower limit (because the smaller the outer diameter of the graft 12, the longer L1 is). Similarly, in this case, 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 is also 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 to 50% of the outer diameter Rm as possible, if the measured value of the maximum protrusion length L1 or the shortening rate is equal to or greater than the standard lower limit value, it may be determined that the maximum protrusion length L1 or the shortening rate in the standard contraction state is also equal to or greater than the standard lower limit value.

[0040] Also, consider a case where the outer diameter of the graft 12 is within a range of 40% or less than 50% of the outer diameter Rm and as close as possible to 50% of the outer diameter Rm. In this case, if the measured value of the maximum protruding length L1 of the hook portion 16 is equal to or less than the standard upper limit (here, 10 mm) or less, the maximum protruding length L1 in a standard contraction state that is 50% of the outer diameter is also equal to or less than the standard upper limit (because the larger the outer diameter of the graft 12, the shorter L1 becomes). Based on this, when the measured value of the maximum protruding length L1 in a range of 40% or more and less than 50% of the outer diameter Rm and as close as possible to 50% of the outer diameter Rm is equal to or less than the standard upper limit, it may be determined that the maximum protruding length L1 in a standard contraction state is also equal to or less than the standard upper 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 when it is cut open in the axial direction and developed on a plane. The dashed lines in Figure 9(A) indicate sutures 42A and 42B.

[0042] The end stent 14 has a plurality of peaks 30A, 30B arranged in the circumferential direction and projecting outward in the axial direction of the graft 12. In this embodiment, all of the peaks 30A, 30B are in contact with each other, so that adjacent peaks 30A, 30B form 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 a ring shape. Note that the peaks 30A, 30B adjacent to each other in the circumferential direction may be separated from each other.

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

[0044] The plurality of 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 peaks 30A are allowed to move relative to the graft 12 in the axial direction at least at the apex 30Aa, and constitute the hooking portion 16 for hooking onto the stent restraining mechanism 108 described above. The fixed peaks 30B are fixed to the graft 12 in the axial and circumferential directions so as to be immovable relative to the graft 12 by being connected by a connecting member 44 described below. The relative movement here refers to the relative movement of the two mentioned (for example, the graft 12 and the apex 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 embodiment) 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 a ring shape.

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

[0047] The fixing parts 40 are connected to the graft 12 by suturing, adhesion, 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 parts 40 are connected to the graft 12 by suturing using a first suture 42A. In this embodiment, the first suture 42A suturing a part of the end stent 14 to the graft 12 along the inner zigzag pattern 38 described above, thereby fixing the multiple fixing parts 40 on the inner zigzag pattern 38 to the graft 12.

[0048] The movable peak 30A includes an apex 30Aa constituting the axially outer end of the movable peak 30A, and a pair of intermediate line portions 30Ab provided between the apex 30Aa and the fixed portion 40. The movable peak 30A is allowed to move in the axial direction 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 so as to be movable in the longitudinal direction of the intermediate line portion 30Ab relative to the graft 12, axially inside the apex 30Aa of the movable peak 30A. The longitudinal direction here refers to the direction in which the intermediate line portion 30Ab extends (axial direction). In addition, to achieve this, the movable peak 30A does not have to be connected to the graft 12 by sewing, adhesion, or the like.

[0049] The connecting member 44 in this embodiment connects each of the pair of intermediate line portions 30Ab on both circumferential sides of the apex 30Aa of the movable mountain 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 in 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) by 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. In each stitch portion 42Ba, 42Bb, a plurality of stitches are 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 by the first stitch portion 42Ba. In addition, the second suture 42B connects the intermediate line portion 30Ab on the outer zigzag pattern 32 to the graft 12 by the aforementioned stitch portion 46 provided at the end of the second stitch portion 42Bb.

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

[0052] The effect of the stent graft 10 described above will be described. See Fig. 11(A) and Fig. 11(B). As described above, the end stent 14 is provided with a pair of fixed parts 40 that are continuous with 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 fixed parts 40 corresponding to the movable peak 30A of the end stent 14 together with the graft 12 also move in the direction D1 so that the circumferential distance between them becomes shorter. As a result, the shorter the circumferential distance between the pair of fixed parts 40, the more the top 30Aa of the movable peak 30A between the pair of fixed parts 40 moves relative to the graft 12 in the direction D2 toward the axially outward direction. Accordingly, the protruding length L of the movable peak 30A protruding axially outward from the axial end of the graft 12 can be increased.

[0053] Furthermore, when the graft 12 expands, the pair of fixing parts 40 of the end stent 14 move together with the graft 12 so that the circumferential distance between them becomes longer. As a result, the longer the circumferential distance between the pair of fixing parts 40 becomes, the more the apex 30Aa of the movable peak 30A moves axially inward relative to the graft 12. Accordingly, the protruding length L of the movable peak 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 peak 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 peak 30A relative to the axial end of the graft 12. In other words, by adopting such a configuration, the movable peak 30A is configured as a hook 16 whose protruding length relative to the axial end 12a of the graft 12 is changeable.

[0055] The stent graft 10 includes a connecting member 44 that connects the intermediate line portion 30Ab to the graft 12 so as to be movable in the longitudinal direction of the intermediate line portion 30Ab of the movable mountain portion 30A relative to the graft 12. Therefore, when the top portion 30Aa of the movable mountain portion 30A moves in the axial direction 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 relative movement of the intermediate line portion 30Ab relative to the graft 12 in the longitudinal direction. For example, consider a case where the pair of fixed portions 40 corresponding to the movable mountain portion 30A moves in the direction D1. In this case, the intermediate line portion 30Ab can be moved in the longitudinal direction of the graft 12 in the connection point by the connecting member 44 in the direction D3, and the entire movable mountain portion 30A can be prevented from being significantly tilted in the axial direction. As a result, the top 30Aa of the movable convex portion 30A can be moved relative to the graft 12 in 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 the movable peaks 30A whose protruding length relative to the graft 12 can be changed. Therefore, compared to the case where the multiple peaks are only the movable peaks 30A, the range in 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 point of the movable peaks 30A, the axial range in which the axial end 12a of the graft 12 is connected to the end stent 14 can be made wider axially outward than in the case where the fixed peaks 30B are not present. As a result, curling of the end at the axial end 12a of the graft 12 can be suppressed.

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

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

[0059] In the above embodiment, an example was described in which the multiple peaks of the end stent 14 are alternately arranged with the movable peaks 30A and the fixed peaks 30B. All of the multiple peaks in this embodiment are movable peaks 30A. In this way, the multiple peaks do not need to include the fixed peaks 30B. As in the first embodiment, the multiple movable peaks 30A in this embodiment are connected to the graft 12 at the pair of intermediate line portions 30Ab by the connecting member 44 made of the 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 described above. In this embodiment, the same effects as those of 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 diagram in which sutures 42A and 42B are omitted from Figure 14(A).

[0061] The plurality of peaks 30A, 30B of this embodiment also includes a movable peak 30A and a fixed peak 30B, and the movable peak 30A and the fixed peak 30B are alternately arranged in the circumferential direction. In this embodiment, the plurality of 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 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 and a phase difference of 1 / 2 of the wavelength. Although an example is shown in which the two second wavy portions 34B are formed by one wire that repeatedly goes around the graft 12, they may be formed by separate wires.

[0062] In addition to the multiple wavy portions 34A, 34B that form the peaks 30A, 30B, the end stent 14 also includes an inner wavy portion 50 that has a wavy shape with the same wavelength as the first wavy portion 34A. The inner wavy portion 50 has a phase difference of 1 / 2 the wavelength of the first wavy portion 34A. 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 disposed between the valleys 34Bb of the second wavy portions 34B adjacent to each other 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 in a zigzag pattern in the circumferential direction.

[0065] In order to satisfy the above-mentioned condition of the first wavelength λ1 of the first wavy portion 34A<the second wavelength λ2 of the second wavy portion 34B, the minimum wavelength of each wave included in the second wavy portion 34B may be longer than the maximum wavelength of each wave included in the first wavy portion 34A. The second wavelength λ2 in this embodiment is an integer multiple (here, as an example, twice) of the first wavelength λ1, but may be other than this. In order to satisfy this condition, when the simple average of the wavelengths of each wave included in the first wavy portion 34A is the first average wavelength, and the simple average of the wavelengths of each wave included in the second wavy portion 34B is the second average wavelength, it is sufficient that the second average wavelength is within a range of ±10% of the integer multiple of the first average wavelength. In order to satisfy the condition of the first wavelength λ1<the second wavelength λ2, the specific long / short relationship between them is not particularly limited to the contents of the embodiment.

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

[0067] In this embodiment, the movable peak 30A is formed by the peak 34Ba of the second wavy portion 34B, and the fixed peak 30B is formed by the peak 34Aa of the first wavy portion 34A. A plurality of fixed portions 40 continuous with the movable peak 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 sewn to the graft 12 along the inner zigzag pattern 38 with the first suture 42A, so that the plurality of fixed portions 40 on the inner zigzag pattern 38 are fixed 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 changing the protruding length by moving the apex 30Aa of the movable peak 30A relative to the graft 12 in the axial direction, as described above, the greater the circumferential distance between the pair of fixed portions 40 connected to the movable peak 30A, the greater the variable range of the protruding length. In order to increase the circumferential distance between the pair of fixed portions 40, for example, it is effective to increase the wavelength of the waves formed by the wavy portion. In this embodiment, the movable peak 30A is provided on the second wavy portion 34B that forms a wavy shape with a second wavelength λ2 that is longer than the first wavelength λ1. Therefore, compared to the case where the second wavelength λ2 is the same as the first wavelength λ1, it is advantageous to increase the variable range of the protruding length of the movable peak 30A (hook portion 16).

[0069] In the first embodiment, an example was described in which the valleys 36 between circumferentially adjacent fixed peaks 30B in one wavy portion are fixed to the graft 12. In contrast, in the present embodiment, the valleys 36 (in the present embodiment, the locations where the hooks 52 are formed) between circumferentially adjacent fixed peaks 30B in the first wavy portion 34A are not connected to the graft 12 by sewing, adhesion, 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 described.

[0070] When the graft 12 tries to contract, it moves so that the circumferential distance between the fixed peaks 30B adjacent in the circumferential direction becomes shorter. As a result, the valleys 36 between the fixed peaks 30B try 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 in the axially outward direction acts on the wavy portion 34A from the fixed point, and the influence of the resistance force F makes it difficult to contract the graft 12. In this respect, 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 need to act on the valleys 36 when the graft 12 tries to contract. Furthermore, even if the fixed peaks 30B are included in the multiple peaks 30A, 30B, it is possible to contract the graft 12 with a light force. In addition, in this embodiment, the same effect as the stent graft 10 of the first embodiment can be obtained.

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

[0072] The delivery device 100 of the embodiment is merely an example. Although an 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 part of the same stent. In addition, specific examples of each operation 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 regarding the lower limit of the maximum protrusion length L1 and the upper limit of the maximum protrusion length L0 are simultaneously satisfied. This is not limiting, and only the conditions regarding either L1 or L0 may be satisfied, or these may not be satisfied. In addition, the condition regarding the shortening rate may not be satisfied. In addition, in order to satisfy the conditions regarding either the shortening rate or the maximum protrusion length L1 or L0, the variable range of the protrusion length L of the graft 12 may be greater than zero.

[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. As the connecting member 44 that connects the intermediate line portion 30Ab of the movable ridge portion 30A to the graft 12, a tubular member that is fixed to the graft 12 and through which the intermediate line portion 30Ab movably passes may be used.

[0077] The above-mentioned embodiment and modified forms are examples. The technical ideas abstracted from these should not be interpreted as being limited to the contents of the embodiment and modified forms. The contents of the embodiment and modified forms are subject to many design changes, such as changes, additions, and deletions of components. In the above-mentioned embodiment, the contents subject to such design changes are emphasized by adding the notation "embodiment". However, design changes are also permitted even in contents not so notated. The hatching on the cross section of the drawing does not limit the material of the object to which the hatching is added. The structures and numerical values ​​referred to in the embodiment and modified forms naturally include those that can be considered to be the same 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 an end stent connected to at least an axial end of the graft, The end stent has a hook portion that is hooked onto a stent restraining mechanism of a delivery device to restrain the expansion of the end stent, A stent graft in which the hook portion can shorten the protruding length of the portion protruding axially outward from the axial end by expanding the axial end together with the end stent.

2. A stent graft as described in claim 1, 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 referred to as the standard contracted state, and the maximum protruding length L1 of the hook portion when the graft is in the standard contracted state is 1 mm or more.

3. 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.

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

5. The stent graft of claim 1 , wherein the variable range of the projection length includes zero.

6. The end stent is A movable convex portion that is convex toward the outside of the graft in the axial direction; A plurality of fixing portions are provided continuously with the movable ridge portion on both circumferential sides of the movable ridge portion and fixed to the graft, The stent graft according to claim 1 , wherein the movable peak portion is allowed to move axially relative to the graft at least at its apex, and constitutes the hook portion.

7. The movable mountain portion includes a middle line portion provided between the top portion and the fixed portion, The stent graft according to claim 6 , 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.

8. The end stent has a plurality of peaks arranged in a circumferential direction of the graft and protruding outward in the axial direction of the graft; The stent graft of claim 6 , wherein the plurality of peaks includes the movable peaks and fixed peaks fixed to the graft.

9. The movable mountain 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 a longitudinal direction of the intermediate line portion; The stent graft according to claim 8 , wherein the fixed peak is connected to the graft axially outboard of a connection point of the movable peak by the connecting member.

10. The end stent has a plurality of peaks arranged in a circumferential direction and protruding outwardly in the axial direction of the graft; The plurality of peaks are formed by at least one wavy portion extending in a circumferential direction, The plurality of peaks include the movable peak and a fixed peak fixed to the graft, The stent graft according to claim 6 , wherein the valleys between the fixed peaks adjacent in the circumferential direction in the wavy portion are allowed to move relative to the graft.

11. The end stent has a plurality of peaks arranged in a circumferential direction and protruding outwardly 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 according to claim 6 , wherein the movable ridge portion is constituted by a ridge portion of the second wavy portion.

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