Stent grafts and methods for deploying stent grafts

Abstract

To provide a stent graft and the like which can be highly accurately arranged even when body fluid flows therein during expansion.SOLUTION: A stent graft 1 comprises: a cylindrical stent 2 which extends in the axial direction; a first graft part 31 which covers at least a portion of the periphery of the stent 2; a second graft part 32 at least a portion of which overlaps the first graft part 31 in the radial direction and which covers at least a portion of the periphery of the stent 2; and a body fluid circulation part which is formed in an overlapping part 312 between the first graft part 31 and the second graft part 32 during expansion of the stent 2 and in which the body fluid can circulate between the inside and the outside of the stent 2. In the overlapping part 312, the base end part of the first graft part 31 is provided on the outer side with respect to the tip part of the second graft part 32 overlapping the first graft part. The body fluid circulation part is the gap formed between the base end part and the tip part during expansion of the stent 2 and allows the body fluid flowing therein from the tip part of the first graft part 31 to flow out to the outside from the inside of the stent 2.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] A stent graft is a medical device that consists of a tubular woven stent made of wire such as metal, and a graft that covers the periphery of the stent (see, for example, Patent Document 1). Stent grafts are inserted into tubular organs in the body, such as blood vessels, trachea, digestive tract, common bile duct, and pancreatic duct, or their connections (entrances and exits), or into holes formed in the body for diagnosis or treatment (for example, holes punctured from the stomach or duodenal bulb to the common bile duct), and form a flow path for bodily fluids through the graft at the target site. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-350785 Summary of the Invention [Problem to be solved by the invention]

[0004] A stent graft inserted into the body in a contracted state is deployed when it reaches a target site, such as the aorta. In the example shown in FIG. 1B (described later), the stent graft 1 is deployed from the distal end of a delivery system DS, with its proximal end housed in the delivery system DS. At this time, bodily fluids, such as blood, flow into the distal end of the deployed stent graft 1 from the distal end of the aorta AO (hereinafter referred to as the central side, back, or tip, and the opposite side as the proximal side, peripheral side, or front). Because the proximal end of the stent graft 1 is housed in the delivery system DS and is essentially occluded, bodily fluids, such as blood, that flow into the distal end are blocked at the proximal end. As a result, the stent graft 1 is subjected to a force pushing back the bodily fluids, such as blood, that flow into the distal end, which may result in a deterioration in the placement accuracy of the stent graft 1.

[0005] The present disclosure has been made in light of these circumstances, and aims to provide a stent graft or the like that can be deployed with high precision even if bodily fluids flow in during deployment. [Means for solving the problem]

[0006] In order to solve the above problems, a stent graft according to one embodiment of the present disclosure comprises an axially extending tubular stent, a first graft portion covering at least a portion of the circumference of the stent, and a second graft portion radially overlapping at least a portion of the first graft portion and covering at least a portion of the circumference of the stent, and during deployment of the stent, body fluids can flow between the inside and outside of the stent graft at the overlapping portion between the first graft portion and the second graft portion.

[0007] The deployment of a stent (or stent graft) refers to the period during which the stent (or stent graft) is transitioning from a contracted state to a deployed or expanded state in the axial overlap section of the first graft portion and the second graft portion.

[0008] Another aspect of the present disclosure is a method of deploying a stent graft by deploying the stent graft from one end thereof to open a flow path through which bodily fluids can pass between the interior and exterior of the stent graft, and then closing the flow path by continuing to deploy the stent graft.

[0009] Yet another aspect of the present disclosure is a stent graft comprising: a cylindrical stent; a graft covering at least a portion of the periphery of the stent; and a valve structure that opens at an early stage of stent deployment to allow bodily fluids to pass between the inside and outside of the stent graft and closes as the stent deployment progresses.

[0010] Any combination of the above components, or any conversion of these expressions into methods, devices, systems, recording media, computer programs, etc., are also encompassed within the present disclosure. [Effects of the Invention]

[0011] According to the present disclosure, a stent graft or the like can be placed with high accuracy even when bodily fluids flow in. [Brief explanation of the drawings]

[0012] [Figure 1] A schematic overview of TEVAR is shown. [Figure 2] 1 shows a schematic diagram of a stent graft according to a first embodiment. [Figure 3] 1 shows a schematic representation of a stent graft according to a first embodiment during deployment. [Figure 4] 1 shows a modified example of the first embodiment. [Figure 5] FIG. 10 is a schematic cross-sectional view of a plane including the axis of a stent graft according to a second embodiment. [Figure 6] 10 shows a modified example of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, with reference to the drawings, a detailed description will be given of modes for carrying out the present disclosure (hereinafter also referred to as embodiments). In the description and / or drawings, identical or equivalent components, members, processes, etc. are designated by the same reference numerals, and redundant description will be omitted. The scale and shape of each part shown in the drawings are set for convenience to simplify the description, and should not be interpreted as limiting unless otherwise specified. The embodiments are merely examples and do not limit the scope of the present disclosure in any way. All features and combinations thereof described in the embodiments are not necessarily essential to the present disclosure.

[0014] While the present disclosure can be applied to stent grafts inserted into any biological site in the human body, this embodiment will be described taking as an example a stent graft inserted into a tortuous aorta for the treatment of aortic aneurysms and aortic dissections. Specifically, the present disclosure will describe a stent graft used in a stent graft repair procedure for the thoracic aorta known as TEVAR (Thoracic Endovascular Aortic Repair).

[0015] Figure 1 shows a schematic overview of TEVAR. As shown in Figure 1, a delivery system DS is inserted from the distal side of the aorta AO (aorta) in which an aortic aneurysm AN (aneurysm) has formed (see Figure 1A). The delivery system DS includes a stent graft 1 and an outer sheath for storing the stent graft 1 inside in a contracted state.

[0016] In the state shown in Figure 1A, the tip of the delivery system DS, guided by the guide wire GW previously inserted into the aorta AO, is inserted to the central side (heart side) of the aortic aneurysm AN. The stent graft 1 is positioned so that it will span the aortic aneurysm AN when deployed.

[0017] From this state, as shown in Figure 1B, only the outer sheath is withdrawn toward the proximal end (the lower side in Figure 1), leaving the internal stent graft 1 intact. With the outer sheath removed, the stent graft 1 deploys a stent 2, formed from a metallic or non-metallic wire such as stainless steel or a nickel-titanium alloy, along with a graft 3, made from a resin such as PET (polyethylene terephthalate) or PTFE (polytetrafluoroethylene), that covers the stent 2. As shown in Figure 1C, the outer sheath is completely withdrawn, and the stent graft 1, now indwelling within the aorta AO, straddles the aortic aneurysm AN, forming an artificial blood vessel directly connecting both sides of the aorta AO with the graft 3. As a result, blood in the aorta AO flows through the graft 3 without flowing into the aortic aneurysm AN, preventing the aortic aneurysm AN from expanding or rupturing.

[0018] As shown in FIG. 1B, the stent graft 1 is deployed from the distal end (upper end in FIG. 1B) of the delivery system DS, with the proximal end (lower end in FIG. 1C) housed in the delivery system DS. At this time, blood flows from the central side of the aorta AO into the distal end of the stent graft 1 being deployed. Because the proximal end of the stent graft 1 is housed in the delivery system DS and is essentially occluded, the blood flowing into the distal end is blocked by the occlusion at the distal end of the delivery system DS. As a result, the stent graft 1 and therefore the delivery system DS are subjected to a force pushing back toward the proximal end (lower side in FIG. 1B) by the blood that has flowed into the distal end, which may push the stent graft 1 toward the periphery, thereby reducing the accuracy of the placement of the stent graft 1.

[0019] According to this embodiment, which will be described in detail below, it is possible to provide a stent graft 1 that can be deployed with high accuracy even if bodily fluids such as blood flow in during deployment.

[0020] Figure 2 shows a schematic diagram of a stent graft 1 according to the first embodiment. The stent graft 1 comprises a cylindrical or tubular stent 2 extending in the axial direction (the left-right direction in Figure 2), and a cylindrical or tubular graft 3 covering the outer or inner circumference of the stent 2.

[0021] The stent 2 is formed into a cylindrical or tubular shape by braiding metallic or non-metallic wires (shown by dashed lines in FIG. 2 for convenience, since they are covered by the graft 3). The graft 3 according to the first embodiment is formed of multiple (four in the example of FIG. 2) partial grafts 31-34 connected in the axial direction. The partial grafts 31-34 are adjacent to each other in the axial direction on the stent 2, and at least partially overlap radially, as described below. Of two partial grafts (partial graft pairs) that are adjacent to each other in the axial direction and overlap radially, the distal-side partial graft corresponds to the first graft portion in the present disclosure, and the proximal-side partial graft corresponds to the second graft portion in the present disclosure. As described below with reference to FIG. 3 and other figures, the stent 2 is deployed distally, so that in each partial graft pair, the distal-side first graft portion deploys before the proximal-side second graft portion. Due to this difference in deployment timing, a gap (described below) temporarily forms in the overlapping portion between the deployed first graft portion and the deploying second graft portion. Furthermore, the first graft portion and the second graft portion move sequentially from the distal end to the proximal end as the stent 2 is deployed (first, a gap is formed at the overlapping portion of the partial grafts 31 and 32, and finally, a gap is formed at the overlapping portion of the partial grafts 33 and 34).

[0022] Each of the partial grafts 31-34, made of a resin such as PET or PTFE, is formed in a cylindrical or tubular shape. Each pair of axially adjacent partial grafts 31-34 overlaps at least partially in the circumferential direction. In the illustrated example, the proximal end (the right end or a portion on the distal side in FIG. 2 ) of partial graft 31, which constitutes the distal end (the left end or a portion on the central side in FIG. 2 ) of the entire graft 3, overlaps with the distal end of partial graft 32, which is adjacent thereto in the axial direction. Similarly, the proximal end of partial graft 32 overlaps with the distal end of partial graft 33, and the proximal end of partial graft 33 overlaps with the distal end of partial graft 34, which constitutes the proximal end of the entire graft 3.

[0023] The first overlapping portion 312 is the overlapping portion between the proximal end of the partial graft 31 and the distal end of the partial graft 32. The second overlapping portion 323 is the overlapping portion between the proximal end of the partial graft 32 and the distal end of the partial graft 33. The third overlapping portion 334 is the overlapping portion between the proximal end of the partial graft 33 and the distal end of the partial graft 34. Each overlapping portion 312, 323, 334 is formed in an annular or band-like shape surrounding a portion of the axial outer periphery of the stent 2. Note that at least a portion of the contact surfaces of each pair of partial grafts 31 to 34 constituting each overlapping portion 312, 323, 334 is not bonded by an adhesive or fixed by sutures or the like along the axial direction. That is, at least a portion of the proximal end of each partial graft 31 to 33 is not bonded or fixed to the distal end of the adjacent partial graft 32 to 34 along the axial direction. On the other hand, at least a portion of the distal end of each partial graft 31 to 34 is bonded or fixed to the stent 2.

[0024] As will be described later, gaps temporarily formed at the overlapping portions 312, 323, 334 of the graft 3 serve to allow bodily fluids such as blood that have entered the inside of the stent graft 1 during deployment of the stent 2 to escape to the outside of the stent graft 1. In the example shown, blood flowing from the left side, which corresponds to the central side of the aorta AO, flows in from the tip (the left end in FIG. 2) of the stent graft 1. At least a portion of the blood flowing from left to right inside the stent graft 1 in this way flows out to the outside of the stent graft 1 through gaps (described later) formed at the overlapping portions 312, 323, 334 during deployment of the stent 2.

[0025] To effectively release blood that has flowed into the stent 2 during deployment, in each of the overlapping portions 312, 323, and 334, the proximal end of the distal partial graft (the first graft portion in this disclosure) is located radially outward from the distal end of the overlapping proximal partial graft (the second graft portion in this disclosure). For example, in the overlapping portion 312, the proximal end of the distal partial graft 31 is located radially outward from the distal end of the overlapping proximal partial graft 32. With this configuration, at least a portion of the blood that has flowed in from the distal end of the partial graft 31 is allowed to escape to the outside of the graft 3 through the overlapping portion 312. Similarly, in the overlapping portion 323, the proximal end of the partial graft 32 is located radially outward from the distal end of the partial graft 33, and in the overlapping portion 334, the proximal end of the partial graft 33 is located radially outward from the distal end of the partial graft 34.

[0026] FIG. 3 is a schematic diagram of a stent graft 1 according to the first embodiment during deployment or at the beginning of deployment. In this example, the stent graft 1 is deployed from the distal end (left end in FIG. 3) of a delivery system DS similar to that shown in FIG. 1 from the distal side (right side) to the proximal side (left side). In the illustrated state, of the partial grafts 31 to 34 that make up the graft 3, the distal end of partial graft 31 is entirely outside the delivery system DS and is almost completely deployed by being forced by the stent 2 expanding from its inside. Meanwhile, only a portion of partial graft 32 has been delivered from the delivery system DS and is being deployed by being forced by the stent 2 expanding from its inside, but is not yet completely deployed. At this time, the distal end of partial graft 32 (the portion overlapping the proximal end of partial graft 31 at first overlapping portion 312) is outside the delivery system DS, and the proximal end of partial graft 32 is housed inside the delivery system DS. Moreover, the partial graft 33 and the partial graft 34 (not shown in FIG. 3) are entirely housed inside the delivery system DS and are in a contracted state.

[0027] During stent deployment, bodily fluids such as blood flow from the proximal side into the stent graft. Here, we compare this with conventional stent grafts. The grafts constituting conventional stent grafts are formed as a single unit, and no temporary gaps are formed in the graft. Therefore, blood (blood flow) flowing from the proximal side flows into the stent graft from the distal end of the graft, which is nearly fully deployed, and is blocked by the distal side of the graft, which is not yet fully deployed or is stored inside the delivery system and in a contracted state. This results in the stent graft, and ultimately the delivery system, being subjected to a force pushing it back toward the distal side by the blood flow from the proximal side, which can degrade the placement accuracy of the stent graft.

[0028] Therefore, in this embodiment, overlapping portions 312, 323, and 334 between the multiple partial grafts 31-34 that make up the graft 3 temporarily form a bodily fluid passage through which blood can flow between the inside and outside of the stent graft 1, effectively allowing blood that has flowed into the stent graft 1 during deployment to escape to the outside of the stent graft 1. In the illustrated example, a gap that is temporarily formed between the proximal end of partial graft 31 and the distal end of partial graft 32 during deployment of the stent 2 serves as the bodily fluid passage, allowing blood that has flowed in from the distal end of partial graft 31 to flow out from the inside of the stent 2 and graft 3 to the outside (schematically indicated by the arrow labeled "blood" in FIG. 3). As a result, blood that has flowed into the interior of the stent graft 2 during deployment can be prevented from being completely blocked, and the force that the stent graft 1 and delivery system DS are subjected to from the blood flow can be reduced, allowing the stent graft 1 to be positioned with high precision.

[0029] The bodily fluid passage portions (gaps temporarily formed at overlapping portions 312, 323, and 334) temporarily formed during deployment of stent 2 or at the beginning of the deployment operation as shown in FIG. 3 are blocked by the progress of the deployment operation from the state shown in FIG. 3 , whereby the deployed stent 2 shown in FIG. 2 biases each of the partial grafts 31-34 (the first and second graft portions in the present disclosure) from the inside to the outside in the radial direction of stent 2. In other words, the stent 2, which is an elastic member, attempts to return from a contracted state to a cylindrical or tubular deployed state due to its elasticity, so that the distal ends of the partial grafts 32, 33, and 34 located on the radially inner side of each overlapping portion 312, 323, and 334 are pressed against the proximal ends of the partial grafts 31, 32, and 33 located on the radially outer side, effectively blocking the gaps. As a result, bodily fluids cannot pass between the inside and outside of stent graft 1. 1C and 2, blood that has flowed in from the central side can circulate normally to the peripheral side without flowing out of the stent graft 1 (inside the aortic aneurysm AN in FIG. 1C) from the overlapping portions 312, 323, 334. In this way, the stent graft 1 according to this embodiment can effectively prevent blood from flowing into the aneurysm AN (so-called endoleak).

[0030] As described above, the method of deploying the stent graft 1 according to this embodiment deploys the stent graft 1 from the distal end (one end) of the stent graft 1, opens the flow paths (gaps temporarily formed at the overlapping portions 312, 323, 334) through which bodily fluids can flow between the inside and outside of the stent graft 1 (FIG. 3), and closes the flow paths (FIG. 2) by continuing to deploy the stent graft 1. In this way, the flow paths (gaps temporarily formed at the overlapping portions 312, 323, 334) through which bodily fluids can flow between the inside and outside of the stent graft 1 form a valve structure that opens at the beginning of the deployment of the stent 2 to allow bodily fluids to flow between the inside and outside of the stent graft 1 (FIG. 3), and closes as the deployment of the stent 2 progresses (FIG. 2).

[0031] To more effectively prevent endoleak from the stent graft 1 after deployment, a swelling material that swells with body fluids such as blood may be provided in at least one of the first graft portion (proximal ends of partial grafts 31, 32, 33) and the second graft portion (distal ends of partial grafts 32, 33, 34) that constitute the overlapping portions (312, 323, 334). The swelling material absorbs and swells the body fluids that flow through the overlapping portions 312, 323, 334 that constitute the body fluid flow portions during deployment of the stent graft 1 or at the beginning of the deployment process (e.g., Figure 3), thereby effectively closing the gaps between the overlapping portions 312, 323, 334 in the stent graft 1 after deployment (e.g., Figure 2). The swelling material may be applied between the first and second graft portions, or may be the constituent material of the thread or fiber that constitutes the first and / or second graft portions.

[0032] Furthermore, when inserting the stent graft 1 into a curved biological site such as the aorta AO shown in Fig. 1, endoleak from the deployed stent graft 1 can be effectively prevented by varying the axial overlap dimension of the first graft portion (proximal ends of partial grafts 31, 32, 33) and the second graft portion (distal ends of partial grafts 32, 33, 34) that make up the overlapping portions (312, 323, 334) of the graft 3 along the circumferential direction of the stent 2, as shown in Fig. 4. In the illustrated example, of the overlapping portions (312, 323, 334) of the graft 3, the upper portions (312L, 323L, 334L) with a relatively large overlap dimension are positioned on the outer side (right side in Fig. 1) of the biological site with a smaller curvature, such as the aorta AO. Of the overlapping portions (312, 323, 334) of the graft 3, the lower portions (312S, 323S, 334S) with a relatively small overlap dimension are placed inside (left side in FIG. 1) the body part such as the aorta AO, which has a large curvature.

[0033] When a stent graft 1 inserted into a curved biological site, such as the aorta AO, is bent, the overlapping first graft portion (proximal ends of partial grafts 31, 32, and 33) and second graft portion (distal ends of partial grafts 32, 33, and 34) significantly shift apart along the axial direction on the outer side (upper side in FIG. 4), where the curvature is smaller. However, in the graft 3 shown in FIG. 4, the overlap dimension (312L, 323L, and 334L) on the outer side, where the curvature is smaller, is larger than the overlap dimension (312S, 323S, and 334S) on the inner side, where the curvature is larger. Therefore, even if there is some shifting during bending, a sufficient overlap dimension is maintained. This effectively prevents endoleak from the stent graft 1 deployed in a curved state, as shown in FIG. 1C.

[0034] In addition, not only when the overlap dimension of graft 3 changes circumferentially as in Figure 4, but also when the overlap dimension of graft 3 is approximately constant circumferentially as in Figure 2, the overlapping first graft portion (proximal ends of partial grafts 31, 32, 33) and second graft portion (distal ends of partial grafts 32, 33, 34) are shifted along the axial direction, which is expected to have the effect of improving the bendability of graft 3 and ultimately stent graft 1.

[0035] 2 and 4, the overlapping portions 312, 323, 334 are provided at approximately equal intervals along the axial direction over substantially the entire graft 3, but the overlapping portions of the graft 3 that constitute the bodily fluid circulation portion may be provided on either the distal or proximal end. However, it is preferable that the overlapping portions of the graft 3 that constitute the bodily fluid circulation portion be provided at least on the distal end side when the stent 2 and / or graft 3 are divided into two in the axial direction.

[0036] Specifically, in the examples of FIGS. 2 and 4, only the overlapping portion 312 provided at the distal end may be provided, and the other overlapping portions 323 and 334 may not be provided. In this case, a single long partial graft (the second graft portion in the present disclosure) is provided instead of the three separate partial grafts 32, 33, and 34. The distal end of this single long partial graft overlaps with the proximal end of the partial graft 31 constituting the first graft portion in the present disclosure to form the overlapping portion 312, which forms a bodily fluid passage portion (gap) through which blood escapes during deployment of the stent graft 1, as shown in FIG. 3. The force exerted by the blood flow pushing back the stent graft 1 and delivery system DS during deployment is thought to have the greatest effect on the placement accuracy of the stent graft 1 in the initial stage of deployment of the stent graft 1, as shown in FIG. 3. Therefore, it is essential to provide the overlapping portion 312 to effectively escape the blood flow at that time.

[0037] 5 is a schematic cross-sectional view of a plane including the axis of a stent graft 1 according to the second embodiment. Components similar to those in the first embodiment are assigned the same reference numerals, and redundant explanations will be omitted. The graft 3 according to the second embodiment comprises a long, cylindrical or tubular partial graft 31 (main graft) extending from its distal end (left end in FIG. 5) to its proximal end (right end in FIG. 5), and annular or band-shaped partial grafts 32, 33, and 34 (secondary grafts) that cover the periphery of partial graft 31 at overlapping portions 312, 323, and 334, respectively, similar to those of the first embodiment in FIG. 2.

[0038] Partial graft 31 constituting the first graft portion in the present disclosure has through-holes 3A, 3B, 3C penetrating radially through stent 2 at each overlapping portion 312, 323, 334. One or more through-holes 3A, 3B, 3C are formed along the circumferential direction of each overlapping portion 312, 323, 334. Partial grafts 32, 33, 34 constituting the second graft portion in the present disclosure cover the through-holes 3A, 3B, 3C formed in partial graft 31 from the outside at each overlapping portion 312, 323, 334.

[0039] The through holes 3A, 3B, 3C in the overlapping portions 312, 323, 334 of the graft 3 allow bodily fluids such as blood that have entered the inside of the stent graft 1 during deployment of the stent 2 to escape to the outside of the stent graft 1. In a conventional stent graft, when the distal end of the stent is deployed outside the delivery system while the proximal end of the stent is housed inside the delivery system and in a contracted state, blood that has flowed into the inside of the stent graft from the central side is blocked.

[0040] However, in this embodiment, partial graft 31 serving as the main graft has a tapered shape from the distal end in the deployed state to the proximal end in the contracted state, which creates a gap between partial graft 31 and at least one of partial grafts 32, 33, and 34 that cover it from the outside. As a result, through-holes 3A, 3B, and 3C that would be blocked by partial grafts 32, 33, and 34 after deployment as shown in Figure 5 are temporarily exposed to the outside of stent graft 1 during deployment (they are not blocked by partial grafts 32, 33, and 34). In this way, blood that has flowed into the inside of stent graft 1 during deployment is effectively released to the outside of stent graft 1 through through-holes 3A, 3B, and 3C that temporarily connect the inside and outside of stent graft 1. Therefore, according to this embodiment, it is possible to prevent the blood that flows into the interior of the stent 2 from being completely blocked during deployment, and it is possible to reduce the force that the stent graft 1 and delivery system DS receive from the blood flow, thereby enabling the stent graft 1 to be positioned with high precision.

[0041] The body fluid passage portions (through-holes 3A, 3B, 3C temporarily exposed to the outside of the stent graft 1) temporarily formed during the deployment of the stent 2 as described above are blocked by the deployed stent 2 urging each of the partial grafts 31-34 from the inside to the outside in the radial direction of the stent 2. In other words, the stent 2, which is an elastic member, attempts to return from a contracted state to a cylindrical or tubular deployed state due to its elasticity, and so at each overlapping portion 312, 323, 334, the radially inner partial graft 31 (main graft) is pressed against the radially outer partial grafts 32, 33, 34 (secondary grafts), effectively blocking the through-holes 3A, 3B, 3C. 1C and 5, blood flowing in from the central side can circulate normally to the peripheral side without flowing out from the overlapping portions 312, 323, 334 (through-holes 3A, 3B, 3C) to the outside of the stent graft 1 (inside the aortic aneurysm AN in FIG. 1C). In this way, the stent graft 1 according to this embodiment can effectively prevent blood from flowing into the inside of the aneurysm AN (endoleak).

[0042] As described above, the method of deploying the stent graft 1 according to this embodiment deploys the stent graft 1 from the tip (one end) of the stent graft 1, opens the flow paths (gaps temporarily formed at the overlapping portions 312, 323, 334) through which bodily fluids can flow between the inside and outside of the stent graft 1, and closes these flow paths by continuing to deploy the stent graft 1. In this way, the flow paths (gaps temporarily formed at the overlapping portions 312, 323, 334) through which bodily fluids can flow between the inside and outside of the stent graft 1 form a valve structure that opens at the beginning of the deployment operation of the stent 2 to allow bodily fluids to flow between the inside and outside of the stent graft 1, and closes as the deployment operation of the stent 2 progresses.

[0043] When inserting the stent graft 1 into a curved biological site such as the aorta AO shown in Fig. 1, the axial overlap dimensions of the overlapping portions 312, 323, and 334 of the graft 3 may be varied along the circumferential direction of the stent 2, as in Fig. 4 of the first embodiment, to effectively prevent endoleak from the deployed stent graft 1. In this embodiment, the axial dimensions of the partial grafts 32, 33, and 34 serving as secondary grafts are the same as the axial overlap dimensions of the overlapping portions 312, 323, and 334 with the partial graft 31 serving as the primary graft, and therefore, the axial dimensions of each of the partial grafts 32 to 34 may be varied along the circumferential direction of the stent 2. Specifically, the axial dimensions of the partial grafts 32 to 34 arranged on the outer side of the biological site, where the curvature is small, are made relatively large, and the axial dimensions of the partial grafts 32 to 34 arranged on the inner side of the biological site, where the curvature is large, are made relatively small.

[0044] In this way, the axial dimension of each of the partial grafts 32-34 on the outside, where the curvature is smaller, is larger than the axial dimension of each of the partial grafts 32-34 on the inside, where the curvature is larger, so even if each of the partial grafts 32-34 shifts slightly relative to the partial graft 31 on the outside during bending, a sufficient overlap dimension is ensured. This effectively prevents endoleak from the stent graft 1 deployed in a curved state, as shown in Figure 1C.

[0045] In Fig. 5, partial grafts 32 to 34 as secondary grafts cover partial graft 31 (through-holes 3A, 3B, 3C) as the main graft from the radial outside, but as shown in Fig. 6, partial grafts 32 to 34 as secondary grafts may cover partial graft 31 (through-holes 3A, 3B, 3C) as the main graft from the radial inside. Note that stent 2 is not shown in Fig. 6.

[0046] The present disclosure has been described above based on the embodiments. Various modifications are possible to the combinations of the components and processes in the exemplary embodiments, and it will be obvious to those skilled in the art that such modifications are included within the scope of the present disclosure.

[0047] Looking at the present disclosure from another perspective, it can also be said to be a stent graft equipped with a valve structure that opens at the beginning of the stent deployment operation to allow bodily fluids to flow between the inside and outside of the stent graft, and closes as the stent deployment operation progresses.

[0048] In the first and second embodiments described above, the graft 3 is composed of multiple partial grafts 31-34. However, a single graft 3 that is not divided into partial grafts may be used. In this case, for example, overlapping portions similar to overlapping portions 312, 323, and 334 can be formed by folding the single graft 3 multiple times in the axial direction. The outer (or inner) portion of the overlapping portions of these grafts 3 corresponds to the first graft portion in the present disclosure, and the inner (or outer) portion corresponds to the second graft portion in the present disclosure. As in the first or second embodiment, each overlapping portion is provided with a gap that functions as a valve structure that allows bodily fluids to escape during deployment of the stent graft 1.

[0049] The configuration, operation, and function of each device and method described in the embodiments can be realized by hardware resources, software resources, or a combination of hardware and software resources. Examples of hardware resources include processors, ROMs, RAMs, and various integrated circuits. Examples of software resources include operating systems, applications, and other programs. [Explanation of symbols]

[0050] 1 stent graft, 2 stent, 3 graft, 3A-3C through-holes, 31-34 partial grafts, 312 first overlapping portion, 323 second overlapping portion, 334 third overlapping portion.

Claims

1. a cylindrical stent extending in an axial direction; a first graft portion covering at least a portion of the circumference of the stent; a second graft portion that radially overlaps at least a portion of the first graft portion and covers at least a portion of the circumference of the stent; Equipped with During deployment of the stent, body fluids can pass between the inside and outside of the stent graft at the overlapping portion between the first graft portion and the second graft portion, In the overlapping portion, a proximal end portion of the first graft portion is provided outside a distal end portion of the second graft portion that overlaps with the proximal end portion of the first graft portion, a gap formed between the base end and the distal end during deployment of the stent, through which bodily fluid that has flowed in from the distal end of the first graft portion can flow out from the inside to the outside of the stent graft; Stent graft.

2. A cylindrical stent extending in an axial direction; a first graft portion covering at least a portion of the circumference of the stent; a second graft portion that radially overlaps at least a portion of the first graft portion and covers at least a portion of the circumference of the stent; Equipped with During deployment of the stent, body fluids can pass between the inside and outside of the stent graft at the overlapping portion between the first graft portion and the second graft portion, After deployment, the stent biases the first graft section or the second graft section from the inside to the outside, thereby preventing bodily fluids from passing between the inside and outside of the stent graft. Stent graft.

3. A cylindrical stent extending in an axial direction; a first graft portion covering at least a portion of the circumference of the stent; a second graft portion that radially overlaps at least a portion of the first graft portion and covers at least a portion of the circumference of the stent; Equipped with During deployment of the stent, body fluids can pass between the inside and outside of the stent graft at the overlapping portion between the first graft portion and the second graft portion, the axial overlap dimension of the first graft section and the second graft section varies circumferentially around the stent. Stent graft.

4. The stent is inserted into a curved biological site, a portion of the overlapping portion having a relatively large overlap dimension is disposed on an outer side of the biological part having a small curvature; a portion of the overlapping portion having a relatively small overlap dimension is disposed on an inner side of the biological part having a large curvature; A stent graft according to claim 3.

5. A cylindrical stent extending in an axial direction; a first graft portion covering at least a portion of the circumference of the stent; a second graft portion that radially overlaps at least a portion of the first graft portion and covers at least a portion of the circumference of the stent; Equipped with During deployment of the stent, body fluids can pass between the inside and outside of the stent graft at the overlapping portion between the first graft portion and the second graft portion, When the stent is divided into two in the axial direction, at least at the distal end side, body fluids can pass between the inside and outside of the stent graft during deployment of the stent. Stent graft.

6. A cylindrical stent extending in an axial direction; a first graft portion covering at least a portion of the circumference of the stent; a second graft portion that radially overlaps at least a portion of the first graft portion and covers at least a portion of the circumference of the stent; Equipped with During deployment of the stent, body fluids can pass between the inside and outside of the stent graft at the overlapping portion between the first graft portion and the second graft portion, At least one of the first graft portion and the second graft portion constituting the overlapping portion includes a swelling material that swells with body fluid. Stent graft.

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