JP2024033350A - Stent graft and expansion method of stent graft - Google Patents

Abstract

PROBLEM TO BE SOLVED: 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

COPYRIGHT: (C)2024,JPO&INPIT

Description

TECHNICAL FIELD This disclosure relates to stent grafts and the like.

A stent graft is a medical device that includes a stent knitted into a cylindrical shape using a wire material such as metal, and a graft that covers the periphery of the stent (for example, Patent Document 1). Stent grafts are used to connect tubular organs in the body such as blood vessels, trachea, gastrointestinal tract, common bile duct, pancreatic duct, etc. The graft is inserted into a hole inserted into the bile duct) to form a flow path for body fluids at the target site.

Japanese Patent Application Publication No. 2000-350785

A stent graft that is inserted into the body in a contracted state is expanded upon reaching a target site such as the aorta. In an example shown in FIG. 1B, which will be described later, the stent graft 1 is deployed from the distal end of the delivery system DS with the proximal end housed in the delivery system DS. At this time, body fluids such as blood from the distal side of the aorta AO (hereinafter referred to as the central side, back, or tip, and the opposite side is referred to as the proximal side, distal side, proximal side, etc.) reach the tip of the stent graft 1 that is being deployed. flows into. Since the proximal end of the stent graft 1 is housed in the delivery system DS and is in a substantially occluded state, body fluids such as blood flowing into the distal end are dammed at the proximal end. As a result, the stent graft 1 is subjected to a force of being pushed back by the body fluid such as blood that has flowed into the distal end, and therefore the placement accuracy of the stent graft 1 may deteriorate.

The present disclosure has been made in view of these circumstances, and it is an object of the present disclosure to provide a stent graft or the like that can be placed with high precision even when body fluids flow in during deployment.

In order to solve the above problems, a stent graft according to an aspect of the present disclosure includes a cylindrical stent extending in the axial direction, a first graft portion that covers at least a portion of the periphery of the stent, and at least one portion of the first graft portion. a second graft portion that overlaps in the radial direction and covers at least a portion of the periphery of the stent, and during deployment of the stent, body fluid is absorbed into the stent-graft at the overlapping portion of the first graft portion and the second graft portion. It can be distributed between inside and outside.

The term "during deployment of a stent (or stent graft)" refers to a period during which the stent (or stent graft) is transitioning from a contracted state to a deployed or expanded state in the axial overlapping section of the first graft section and the second graft section. .

Another aspect of the disclosure is a method of deploying a stent graft. This method involves deploying the stent-graft from one end to open a channel through which bodily fluids can flow between the interior and exterior of the stent-graft, and continuing to deploy the stent-graft to close the channel.

Yet another aspect of the present disclosure is a stent graft. This stent-graft includes a cylindrical stent, a graft that covers at least a portion of the periphery of the stent, and opens during the initial deployment operation of the stent to allow body fluid to flow between the inside and outside of the stent-graft. and a valve structure that closes as the movement progresses.

Note that the present disclosure also includes arbitrary combinations of the above-mentioned components and conversions of these expressions into methods, devices, systems, recording media, computer programs, and the like.

According to the present disclosure, a stent graft or the like can be placed with high precision even when body fluid flows in.

A schematic overview of TEVAR is shown. 1 schematically shows a stent graft according to a first embodiment. 1 schematically shows a stent-graft according to a first embodiment during deployment. A modification of the first embodiment is shown. FIG. 3 is a schematic cross-sectional view of a plane including the axis of a stent graft according to a second embodiment. A modification of the second embodiment is shown.

Hereinafter, modes for implementing the present disclosure (hereinafter also referred to as embodiments) will be described in detail with reference to the drawings. In the description and/or drawings, the same or equivalent components, members, processes, etc. are denoted by the same reference numerals, and redundant description will be omitted. The scales and shapes of the parts shown in the drawings are set for convenience to simplify the explanation, and should not be interpreted in a limited manner unless otherwise stated. The embodiments are illustrative and do not limit the scope of the present disclosure. Not all features or combinations thereof described in the embodiments are necessarily essential to the present disclosure.

The present disclosure can be applied to a stent graft inserted into any biological site of the human body, but in this embodiment, a stent graft inserted into a curved aorta for treatment of aortic aneurysm or aortic dissection will be described as an example. Specifically, a stent graft used for stent graft insertion in the thoracic aorta called TEVAR (Thoracic Endovascular Aortic Repair) will be described.

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

In the state shown in FIG. 1A, the distal end of the delivery system DS guided by the guide wire GW that was previously inserted into the aorta AO has been inserted to the central side (heart side) of the aortic aneurysm AN. The stent graft 1 is positioned at a position where it straddles the aortic aneurysm AN when expanded.

From this state, as shown in FIG. 1B, only the outer sheath is pulled out toward the proximal end (lower side in FIG. 1), leaving the internal stent graft 1 intact. In the stent graft 1 from which the outer sheath has been removed, the stent 2 is made of metal or non-metallic wire such as stainless steel or nickel titanium alloy, and the stent 2 is covered with PET (polyethylene terephthalate) or PTFE (polytetraphthalate). It is developed together with a graft 3 made of resin such as fluoroethylene). As shown in FIG. 1C, the stent graft 1 whose outer sheath has been completely withdrawn and placed in the aorta AO straddles the aortic aneurysm AN, and an artificial blood vessel directly connecting both sides of the aortic aneurysm AN is formed by the graft 3. As a result, the blood within the aorta AO does not flow into the aortic aneurysm AN, but instead flows within the graft 3, thereby preventing expansion and rupture of the aortic aneurysm AN.

As shown in FIG. 1B, the stent graft 1 that is deployed from the distal end (upper end in FIG. 1B) of the delivery system DS has its proximal end (lower end in FIG. 1C) housed in the delivery system DS, and the distal end ( It unfolds from the upper end in FIG. 1B). At this time, blood flows from the central side of the aorta AO into the distal end of the stent graft 1 that is being expanded. Since the proximal end of the stent graft 1 is housed in the delivery system DS and is in a substantially occluded state, blood flowing into the distal end is dammed up by the occluded part at the distal end of the delivery system DS. As a result, the stent graft 1 and the delivery system DS receive a force that pushes the stent graft 1 back toward the proximal end (lower side in FIG. 1B) by the blood that has flowed into the distal end, which pushes the stent graft 1 toward the distal end and reduces the placement accuracy of the stent graft 1. There is a risk that it may get worse.

According to this embodiment, which will be described in detail below, it is possible to provide a stent graft 1 that can be placed with high precision even when body fluids such as blood flow in during deployment.

FIG. 2 schematically shows the stent graft 1 according to the first embodiment. The stent graft 1 includes a cylindrical or tubular stent 2 that extends in the axial direction (left-right direction in FIG. 2), and a cylindrical or tubular graft 3 that covers the outer or inner periphery of the stent 2.

The stent 2 is formed into a cylindrical or tubular shape by weaving metallic or non-metallic wire rods (in FIG. 2, they are covered with the graft 3 and are shown by broken lines for convenience). The graft 3 according to the first embodiment is formed by a plurality of (four in the example of FIG. 2) partial grafts 31 to 34 connected in the axial direction. Each of the partial grafts 31 to 34 is axially adjacent to each other in the stent 2 and at least partially overlaps in the radial direction, as described below. Of two partial grafts (partial graft pair) that are adjacent to each other in the axial direction and overlap in the radial direction, one partial graft on the distal side corresponds to the first graft portion in the present disclosure, and the other partial graft on the proximal side corresponds to the first graft portion in the present disclosure. corresponds to the second graft portion in the present disclosure. As will be described later with reference to FIG. 3 and the like, the stent 2 is deployed from the distal side, so in each partial graft pair, the first graft section on the distal side is deployed before the second graft section on the proximal side. Due to such a difference in deployment timing, a gap, which will be described later, is temporarily formed in the overlapping portion of the first graft section that has been deployed and the second graft section that is being deployed. Furthermore, as the stent 2 is expanded, the first graft portion and the second graft portion are sequentially moved from the distal side to the proximal side (first, a gap is formed in the overlapping portion of the partial grafts 31 and 32, and finally the partial graft portion A gap is formed at the overlapping portion of 33 and 34).

Each of the partial grafts 31 to 34 made of resin such as PET or PTFE is formed into a cylindrical or tubular shape. Each pair of axially adjacent partial grafts 31-34 overlaps at least in part in the circumferential direction. In the illustrated example, the proximal end (the right end or part of the distal side in FIG. 2) of the partial graft 31 that constitutes the distal end (the left end or part of the central side in FIG. 2) of the entire graft 3 is It overlaps the distal end of the axially adjacent partial graft 32 . 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 graft 3 as a whole. .

The first overlapping portion 312 is an overlapping portion between the proximal end of the partial graft 31 and the distal end of the partial graft 32, and the second overlapping portion 323 is an 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 an overlapping portion of the proximal end of the partial graft 33 and the distal end of the partial graft 34. Each of the overlapping portions 312, 323, and 334 is formed in an annular shape or a circular band shape surrounding a part of the outer circumference of the stent 2 in the axial direction. Note that at least a portion of the contact surfaces of each pair of partial grafts 31 to 34 constituting each of the overlapping portions 312, 323, and 334 are not bonded along the axial direction with an adhesive or the like, and are fixed with sutures or the like. Not even done. That is, at least some of the proximal ends of partial grafts 31 to 33 are not adhered to or fixed to the distal ends of adjacent partial grafts 32 to 34 along the axial direction. On the other hand, at least some of the distal ends of the partial grafts 31 to 34 are glued or fixed to the stent 2.

As will be described later, the gaps temporarily formed in each of the overlapping portions 312, 323, and 334 in the graft 3 allow body 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. play a role. In the illustrated example, blood flowing from the left side corresponding to the central side of the aorta AO flows from the tip of the stent graft 1 (the left end in FIG. 2). At least a portion of the blood flowing inside the stent-graft 1 from left to right in this manner flows out of the stent-graft 1 through gaps (described later) formed in each of the overlapping portions 312, 323, and 334 during deployment of the stent-graft 1. .

In order to effectively release the blood that has flowed into the inside of the stent 2 during deployment, in each of the overlapping parts 312, 323, 334, the proximal end of the distal partial graft (the first graft part in the present disclosure) is is provided radially outward from the distal end of the proximal partial graft (second graft portion in the present disclosure) that overlaps with the proximal partial graft. For example, in the overlapping portion 312, the proximal end of the distal partial graft 31 is provided radially outward from the distal end of the proximal partial graft 32 that overlaps therewith. With this configuration, at least a portion of the blood flowing from the distal end of the partial graft 31 escapes to the outside of the graft 3 through the overlapping portion 312. Similarly, in the overlap section 323, the proximal end of the partial graft 32 is provided radially outward from the distal end of the partial graft 33, and in the overlap section 334, the proximal end of the partial graft 33 is provided at the distal end of the partial graft 34. It is provided on the outer side in the radial direction.

FIG. 3 schematically shows the stent graft 1 according to the first embodiment during deployment or in the initial stage of deployment operation. In the example shown in this figure, the stent graft 1 is deployed from the distal end (left end in FIG. 3) of the delivery system DS similar to that in FIG. 1 from the distal side (right side) to the central side (left side). In the illustrated state, among the partial grafts 31 to 34 constituting the graft 3, the partial graft 31 constituting the distal end portion is entirely outside the delivery system DS, and is biased by the stent 2 expanding from the inside to be almost completely completed. It is being expanded to. On the other hand, only a portion of the partial graft 32 has been sent out from the delivery system DS, and is being deployed under the influence of the stent 2 expanding from inside, but has not been completely deployed yet. At this time, the distal end of the partial graft 32 (the part that overlaps with the proximal end of the partial graft 31 in the first overlapping section 312) is outside the delivery system DS, and the proximal end of the partial graft 32 is inside the delivery system DS. It is stored in. Further, the partial graft 33 and the partial graft 34 (not shown in FIG. 3) are completely housed inside the delivery system DS and are in a contracted state.

Thus, during deployment of the stent, body fluids such as blood flow into the interior of the stent graft, for example from the central side. Here, a comparison will be made with a conventional stent graft. The grafts that make up conventional stent grafts are integrally formed and there are no temporary gaps formed in the graft. Therefore, blood (blood flow) flowing from the central side flows into the inside of the stent graft from the tip of the almost completely expanded graft, and if it is not yet completely expanded, or it is stored inside the delivery system and contracts. The distal side of the graft is dammed. In this case, the stent graft and thus the delivery system are subjected to a force that is pushed back toward the peripheral side by the blood flow from the central side, which may deteriorate the placement accuracy of the stent graft.

Therefore, in this embodiment, the overlapping parts 312, 323, and 334 between the plurality of partial grafts 31 to 34 constituting the graft 3 temporarily create a body fluid circulation part where blood can flow between the inside and outside of the stent graft 1. The blood flowing into the stent-graft 1 during deployment is effectively released to the outside of the stent-graft 1. In the illustrated example, a gap temporarily formed between the proximal end of the partial graft 31 and the distal end of the partial graft 32 during deployment of the stent 2 serves as a body fluid circulation section, and the gap from the distal end of the partial graft 31 to The inflowing blood can flow out from the interior of the stent 2 and graft 3 (schematically indicated by the "blood" arrow in FIG. 3). As a result, it is possible to prevent the blood that has flowed into the stent 2 from being completely dammed up during deployment, and it is possible to reduce the force that the stent graft 1 and the delivery system DS receive from the blood flow. Can be placed.

The body fluid circulation portion (the gap temporarily formed in the overlapping portions 312, 323, 334) that is temporarily formed during the deployment of the stent 2 or at the beginning of the deployment operation as shown in FIG. The stent 2 after deployment as shown in FIG. It is blocked by this. In other words, since the stent 2, which is an elastic member, tends to return from a contracted state to a cylindrical or tubular expanded state due to elasticity, each partial graft 32 located on the radially inner side of each overlapped portion 312, 323, 334 , 33, 34 are pressed against the proximal ends of the respective partial grafts 31, 32, 33 located on the outside in the radial direction, thereby effectively closing the gap. As a result, body fluids cannot flow between the inside and outside of the stent graft 1. Therefore, in the stent graft 1 after deployment shown in FIGS. 1C and 2, blood that has flowed in from the central side flows out of the stent graft 1 from the overlapping portions 312, 323, and 334 (inside the aortic aneurysm AN in FIG. 1C). It can be distributed normally to the peripheral side without any damage. In this manner, the stent graft 1 according to the present embodiment can effectively prevent blood from flowing into the aneurysm AN (so-called endoleak).

As described above, the method for deploying the stent graft 1 according to the present embodiment involves deploying the stent graft 1 from the distal end (one end) of the stent graft 1, and allowing body fluids to flow between the inside and outside of the stent graft 1 through channels (overlapping The gap temporarily formed in the sections 312, 323, 334) is opened (FIG. 3) and the flow path is closed by continuing to deploy the stent-graft 1 (FIG. 2). In this way, the flow path (the gap temporarily formed in the overlapping parts 312, 323, 334) through which body fluid can flow between the inside and outside of the stent graft 1 opens at the initial stage of the deployment operation of the stent 2, and the stent graft 1 It constitutes a valve structure that allows bodily fluids to flow between the inside and outside of the stent (FIG. 3) and closes as the deployment operation of the stent 2 progresses (FIG. 2).

In order to more effectively prevent endoleak from the stent graft 1 after deployment, the first graft portion (proximal end portions of the partial grafts 31, 32, 33) and the first graft portion constituting the overlapping portion (312, 323, 334) A swelling material that swells with body fluids such as blood may be provided on at least one of the two graft sections (the distal ends of the partial grafts 32, 33, and 34). During the deployment of the stent graft 1 or at the beginning of the deployment operation (for example, FIG. 3), the swelling material absorbs the body fluid flowing through each of the overlapping parts 312, 323, and 334 that constitute the body fluid circulation section and swells. ) in the stent graft 1, the gaps between the respective overlapping portions 312, 323, 334 are effectively closed. Note that the swelling material may be applied between the first graft section and the second graft section, or may be a constituent material of the threads or fibers that constitute the first graft section and/or the second graft section.

Furthermore, when inserting the stent graft 1 into a curved body part such as the aorta AO shown in FIG. The axial overlapping dimension of the graft portion (proximal end portions of the partial grafts 31, 32, and 33) and the second graft portion (distal end portions of the partial grafts 32, 33, and 34) is changed along the circumferential direction of the stent 2. By doing so, end leak from the stent graft 1 after deployment can be effectively prevented. In the illustrated example, among the overlapping portions (312, 323, 334) of the graft 3, the upper portions (312L, 323L, 334L) with relatively large overlapping dimensions are located on the outside of the body part such as the aorta AO, which has a small curvature (Fig. (on the right side). In addition, among the overlapping parts (312, 323, 334) of the graft 3, the lower part (312S, 323S, 334S) with relatively small overlapping dimensions is located inside the large curvature of the biological part such as the aorta AO (left side in Fig. 1). will be placed in

When the stent graft 1 inserted into a curved biological site such as the aorta AO is curved, the first graft portions (the proximal ends of the partial grafts 31, 32, and 33 ) and the second graft portion (the distal ends of the partial grafts 32, 33, 34) are largely shifted apart along the axial direction. However, in graft 3 shown in FIG. 4, the overlapping dimensions (312L, 323L, 334L) on the outside with small curvature are larger than the overlapping dimensions (312S, 323S, 334S) on the inside with large curvature, so there was some deviation during curvature. However, sufficient overlap dimensions are ensured. Therefore, end leak from the stent graft 1 deployed in a curved state as shown in FIG. 1C is effectively prevented.

Note that, not only when the overlapping dimension of the graft 3 changes along the circumferential direction as shown in FIG. 4, but also when the overlapping dimension of the graft 3 is approximately constant along the circumferential direction as shown in FIG. When the first graft section (the proximal end of the partial grafts 31, 32, 33) and the second graft section (the distal end of the partial grafts 32, 33, 34) are displaced along the axial direction, the graft 3 and the stent graft 1 The effect of improving curvature can also be expected.

In the configuration examples shown in FIGS. 2 and 4, the plurality of overlapping parts 312, 323, and 334 are provided at approximately equal intervals along the axial direction over almost the entire graft 3, but they constitute a body fluid circulation section. The overlapping portion of the graft 3 may be provided on either the distal side or the proximal side. However, the overlapping portion of the graft 3 constituting the body fluid circulation section is preferably provided at least on the distal end side when the stent 2 and/or the graft 3 is divided into two in the axial direction.

Specifically, in the examples of FIGS. 2 and 4, only the overlapping portion 312 provided on the distal end side may be provided, and the other overlapping portions 323 and 334 may not be provided. In this case, one elongated partial graft (second graft portion in the present disclosure) is provided instead of the three divided partial grafts 32, 33, and 34. The distal end of this one elongated partial graft overlaps the proximal end of the partial graft 31 constituting the first graft section in the present disclosure to form an overlapping portion 312, and as shown in FIG. 3, the stent graft 1 During development, it forms body fluid circulation areas (gap) that allow blood to escape. The influence of the force pushing back the stent graft 1 and delivery system DS from the bloodstream during deployment on the placement accuracy of the stent graft 1 is considered to be greatest at the beginning of the deployment operation of the stent graft 1 as shown in FIG. It is important to provide an overlap 312 that effectively vents blood flow.

FIG. 5 is a schematic cross-sectional view of a plane including the axis of the stent graft 1 according to the second embodiment. Components similar to those in the first embodiment are given the same reference numerals and redundant explanations will be omitted. The graft 3 according to the second embodiment includes 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); A partial graft 32, a partial graft 33, and a partial graft 34 (subgraft) in the form of an annular or circular band that cover the periphery of the partial graft 31 are provided in the same overlapping parts 312, 323, and 334 as in the first embodiment.

The partial graft 31 constituting the first graft portion in the present disclosure has through holes 3A, 3B, and 3C that penetrate in the radial direction of the stent 2 in each of the overlapping portions 312, 323, and 334. One or more through holes 3A, 3B, and 3C are formed along the circumferential direction of each overlapping portion 312, 323, and 334. The partial graft 32, the partial graft 33, and the partial graft 34 constituting the second graft portion in the present disclosure are arranged so that the through holes 3A, 3B, and 3C formed in the partial graft 31 are connected to the outside in the overlapping portions 312, 323, and 334. Cover from

Each through hole 3A, 3B, 3C in each overlapping portion 312, 323, 334 of the graft 3 allows body 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 conventional stent-grafts, the distal end of the stent extends outside the delivery system and is deployed, while the proximal end of the stent is stored inside the delivery system and is in a contracted state. Blood flowing into the area is dammed up.

However, in this embodiment, the partial graft 31 as the main graft has a tapered shape from the distal end side in the expanded state to the proximal end side in the contracted state, so the partial graft 31 covering it from the outside is A gap is created between at least one of 32, partial graft 33, and partial graft 34. Therefore, the through holes 3A, 3B, and 3C, which are blocked by the partial grafts 32, 33, and 34 after deployment as shown in FIG. (not occluded by partial graft 32, partial graft 33, partial graft 34). In this way, blood that has flowed into the inside of the stent graft 1 during deployment is effectively released to the outside of the stent graft 1 through the through holes 3A, 3B, and 3C that temporarily communicate between the inside and outside of the stent graft 1. Therefore, according to the present embodiment, it is possible to prevent the blood that has flowed into the stent 2 from being completely dammed up during deployment, and it is possible to reduce the force that the stent graft 1 and the delivery system DS receive from the blood flow. The stent graft 1 can be placed with high precision.

The body fluid circulation portions (the through holes 3A, 3B, and 3C temporarily exposed to the outside of the stent graft 1) that are temporarily formed during the deployment of the stent 2 as described above are the parts of the stent 2 after deployment. The grafts 31 to 34 are closed by forcing the stent 2 from the inside in the radial direction to the outside. In other words, since the stent 2, which is an elastic member, tries to return from a contracted state to a cylindrical or tubular expanded state due to its elasticity, the partial graft 31 ( The main graft) is pressed against the radially outer partial grafts 32, 33, and 34 (secondary grafts) to effectively close the through holes 3A, 3B, and 3C. Therefore, in the stent graft 1 after deployment shown in FIGS. 1C and 5, blood flowing in from the central side is transferred from the overlapping portions 312, 323, and 334 (through holes 3A, 3B, and 3C) to the outside of the stent graft 1 ( It can normally flow to the distal side without flowing into the aortic aneurysm AN (in FIG. 1C). In this manner, the stent graft 1 according to the present embodiment can effectively prevent blood from flowing into the aneurysm AN (endoleak).

As described above, the method for deploying the stent graft 1 according to the present embodiment involves deploying the stent graft 1 from the distal end (one end) of the stent graft 1 and allowing body fluids to flow between the inside and outside of the stent graft 1 through channels (overlapping). The gap temporarily formed in the sections 312, 323, 334) is opened, and the flow path is closed by continuing to expand the stent-graft 1. In this way, the flow path (the gap temporarily formed in the overlapping parts 312, 323, 334) through which body fluid can flow between the inside and outside of the stent graft 1 opens at the initial stage of the deployment operation of the stent 2, and the stent graft 1 The stent 2 has a valve structure that allows bodily fluids to flow between the inside and outside of the stent 2 and closes as the stent 2 expands.

When inserting the stent graft 1 into a curved biological site such as the aorta AO shown in FIG. By changing the length along the circumferential direction of the stent 2, end leak from the stent graft 1 after deployment may be effectively prevented. In this embodiment, the axial dimensions of the partial grafts 32, 33, and 34 as secondary grafts are the same as the axial overlapping dimensions of the overlapping portions 312, 323, and 334 with the partial grafts 31 as the main graft. Therefore, the axial dimension of each of the partial grafts 32 to 34 may be changed along the circumferential direction of the stent 2. Specifically, the axial dimension of each of the partial grafts 32 to 34 placed on the outside of the body part where the curvature is small is made relatively large, and the axial dimension of each of the partial grafts 32 to 34 placed on the inside of the body part where the curvature is large is made relatively large. The axial dimension of is made relatively small.

In this way, since the axial dimension of each partial graft 32 to 34 on the outside with small curvature is larger than the axial dimension of each partial graft 32 to 34 on the inside with large curvature, each partial graft 32 on the outside when curved Even if .about.34 is slightly shifted from the partial graft 31, a sufficient overlapping dimension is ensured. Therefore, end leak from the stent graft 1 deployed in a curved state as shown in FIG. 1C is effectively prevented.

In FIG. 5, the partial grafts 32 to 34 as the secondary grafts covered the partial graft 31 (through holes 3A, 3B, 3C) as the main graft from the outside in the radial direction, but as shown in FIG. The partial grafts 32 to 34 as secondary grafts may cover the partial graft 31 (through holes 3A, 3B, 3C) as the main graft from the inside in the radial direction. Note that in FIG. 6, illustration of the stent 2 is omitted.

The present disclosure has been described above based on the embodiments. It will be obvious to those skilled in the art that various modifications can be made to the combinations of components and processes in the exemplary embodiments, and such modifications are within the scope of the present disclosure.

Viewing the present disclosure from another perspective, a stent graft includes a valve structure that opens at the initial stage of the stent deployment operation to allow body fluid to flow between the inside and outside of the stent graft, and closes as the stent deployment progresses. I can say that.

In the first and second embodiments described above, the graft 3 was composed of a plurality of partial grafts 31 to 34, but a single graft 3 that is not divided into partial grafts may be used. In this case, for example, by folding back the one graft 3 in the axial direction multiple times, an overlapping portion similar to the overlapping portions 312, 323, and 334 can be formed. The outer (or inner) part of the overlapping portion of these grafts 3 becomes the first graft part in the present disclosure, and the inner (or outer) part becomes the second graft part in the present disclosure. Similar to the first or second embodiment, each overlap is provided with a gap that acts as a valve structure to allow bodily fluids to escape during deployment of the stent-graft 1.

Note that the configuration, operation, and function of each device and each method described in the embodiments can be realized by hardware resources, software resources, or by cooperation of hardware resources and software resources. As hardware resources, for example, a processor, ROM, RAM, and various integrated circuits can be used. As software resources, for example, programs such as operating systems and applications can be used.

1 stent graft, 2 stent, 3 graft, 3A to 3C through hole, 31 to 34 partial graft, 312 first overlapping portion, 323 second overlapping portion, 334 third overlapping portion.

Claims (10)

a cylindrical stent extending in the axial direction;
a first graft portion covering at least a portion of the periphery of the stent;
a second graft portion that at least partially overlaps the first graft portion in the radial direction and covers at least a portion of the periphery of the stent;
Equipped with
During deployment of the stent, body fluids can flow between the interior and exterior of the stent-graft at the overlap between the first graft section and the second graft section;
stent graft. In the overlapping portion, the proximal end portion of the first graft portion is provided outside of the distal end portion of the second graft portion that overlaps therewith,
Body fluid flowing from the distal end of the first graft part can flow out from the inside of the stent graft through a gap formed between the proximal end and the distal end during deployment of the stent.
A stent graft according to claim 1. A through hole passing through the stent in a radial direction is formed in the first graft portion,
The second graft portion covers the through hole from the outside,
Body fluid flowing from the distal end of the first graft part can flow out from the inside of the stent graft through the through hole that is not occluded by the second graft part during deployment of the stent.
A stent graft according to claim 1. The expanded stent urges the first graft section or the second graft section from the inside to the outside, so that bodily fluids cannot flow between the inside and outside of the stent graft;
A stent graft according to any one of claims 1 to 3. The stent graft according to any one of claims 1 to 3, wherein the axial overlapping dimension of the first graft section and the second graft section varies along the circumferential direction of the stent. The stent is inserted into a curved biological site,
Of the overlapping portions, a portion where the overlapping dimension is relatively large is arranged on the outside of the biological part where the curvature is small;
Of the overlapping portions, a portion where the overlapping dimension is relatively small is arranged inside the biological part having a large curvature.
A stent graft according to claim 5. The stent graft according to any one of claims 1 to 3, wherein body fluid can flow between the inside and outside of the stent graft during deployment of the stent at least on the distal end side when the stent is bisected in the axial direction. . The stent graft according to any one of claims 1 to 3, wherein at least one of the first graft part and the second graft part constituting the overlapping part includes a swelling material that swells with body fluid. deploying the stent graft from one end of the stent graft;
opening a flow path through which bodily fluids can flow between the interior and exterior of the stent-graft;
closing the flow path by continuing to deploy the stent-graft;
How to deploy a stent graft. a cylindrical stent,
a graft covering at least a portion of the periphery of the stent;
a valve structure that opens at the beginning of the deployment operation of the stent to allow body fluid to flow between the inside and outside of the stent graft, and closes as the deployment operation of the stent progresses;
A stent graft comprising:

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