JP2024052036A - Embolization material - Google Patents

Abstract

[Problem] To prevent or suppress deformation of a stent graft placed in an aneurysm when discharged, and to prevent or suppress distal embolization of side branches in the aneurysm. [Solution] The present invention provides an embolic material 10d capable of embolizing a blood vessel connected to an aneurysm space or capable of being placed in the aneurysm space, the embolic material having a plurality of substantially spherical embolic bodies 11d and a flexible connecting member 14 connecting each of the plurality of embolic bodies to one or two embolic bodies 11d at intervals, and each of the plurality of embolic bodies is compressible and deformable so as to fit into a blood vessel having a diameter smaller than that of each of the plurality of embolic bodies. [Selected Figure] Figure 21

Description

The present invention relates to an embolic material.

There is no medical treatment for aneurysms (aortic aneurysms) that develop in a patient's aorta to prevent the aneurysm from growing larger or rupturing, and surgical treatment (operation) is generally performed for aneurysms large enough to rupture. In addition, surgery for aortic aneurysms has traditionally been dominated by artificial vascular replacement surgery, in which an artificial blood vessel is implanted via laparotomy or thoracic opening, but in recent years, the use of the less invasive stent graft insertion procedure (Endovascular Aneurysm Repair; EVAR) has been rapidly expanding.

As an example, in stent graft insertion surgery for abdominal aortic aneurysm (AAA), a catheter with a stent graft at its tip is inserted through the patient's peripheral blood vessels, and the stent graft is deployed and placed at the site of the aneurysm, blocking blood flow to the aneurysm and preventing the aneurysm from rupturing.

Generally, stent grafts used in stent graft insertion have a structure that can be assembled from two types of components: a "main body" with a branching section that branches into an approximately Y shape, and "legs" that are attached to the branching section and are attached to the right iliac artery and left iliac artery, respectively.

Therefore, during stent graft insertion surgery, blood may leak from around the stent graft due to insufficient adhesion of the inserted stent graft, or blood may flow back from small blood vessels branching off from the aneurysm, resulting in a so-called "end leak," in which blood remains flowing within the aneurysm. In this case, the blood flow that has entered the aneurysm puts pressure on the aneurysm wall, creating a potential risk of the aneurysm rupturing.

The following Patent Document 1 discloses a device that includes a catheter capable of holding a compressed, relatively elongated sponge (called an embolic material) in its lumen, and a plunger that pushes the embolic material held in the catheter into the aneurysm filled with blood, in order to block the remaining blood flow into an aortic aneurysm caused by an end leak. The sponge used in this device expands immediately when exposed to blood, so when it is pushed into the aneurysm and absorbs the blood inside the aneurysm, it expands (swells), and is left in that state inside the aneurysm to block the blood flow and prevent rupture.

U.S. Pat. No. 9,561,096

The inventors are studying ways to improve the issue of the embolic material being elongated and long as described in Patent Document 1, which may cause deformation and crushing of the stent graft placed in the aneurysm when an excessive amount of such embolic material is ejected into the aneurysm. The inventors are also focusing on the issue of preventing or suppressing the improved embolic material from flowing into side branch blood vessels (also called branch blood vessels, hereinafter referred to as side branches) that branch off from the aneurysm (distal embolization).

The present invention aims to prevent or suppress deformation of a stent graft placed within an aneurysm when ejected, and to prevent or suppress distal embolism of side branches within the aneurysm.

The above object can be achieved by the aspects (1) to (20) of the present invention.
(1) An embolic material capable of embolizing a blood vessel connected to an aneurysm space or capable of being placed in the aneurysm space,
A plurality of embolus bodies formed in a substantially spherical shape;
and a flexible connecting portion connecting each of the plurality of occlusion bodies to one or two of the occlusion bodies at intervals;
Each of the plurality of embolic bodies is an embolic material that is compressible and deformable so as to fit into a blood vessel having a diameter smaller than that of each of the plurality of embolic bodies.
(2) The embolic material according to (1), wherein the connecting portion connects a plurality of the embolic bodies in a ring shape.
(3) The embolic material according to (1) or (2), wherein the connecting portion connects adjacent embolic bodies to each other so that the embolic bodies can be spaced apart from each other by a distance greater than the diameter of the embolic body.
(4) The embolic material according to any one of (1) to (3), wherein the plurality of embolic bodies comprises 3 to 10 embolic bodies.
(5) The embolic material according to any one of (1) to (4), wherein the diameter of each of the plurality of embolic bodies is approximately uniform.
(6) An embolic material according to any one of (1) to (5), wherein each of the plurality of embolic bodies is compressible and deformable so as to fit independently into a side branch blood vessel having a diameter of 2 to 5 mm branching off from a blood vessel in which a stent graft for abdominal aortic aneurysm is placed.
(7) The embolic material according to (6), wherein each of the plurality of embolic bodies is compressible and deformable so as to be in close contact with the side branch blood vessel over the entire circumferential direction.
(8) The abdominal aortic aneurysm is formed in a substantially spherical shape and has an embolus capable of being filled into an aneurysmal space formed between the abdominal aortic aneurysm and the stent graft;
The embolic body is an embolic material that can be compressed and deformed so that the embolic body can fit alone into a side branch blood vessel having a diameter of 2 to 5 mm that branches off from the blood vessel in which the stent graft of the abdominal aortic aneurysm is placed.
(9) An embolization body formed in a substantially spherical shape and capable of being filled into an aneurysmal space formed between an abdominal aortic aneurysm and a stent graft,
The embolic body has a diameter of 4 to 7 mm when filled into the aneurysm space, and is configured to be compressed and deformed to fit into a side branch blood vessel branching off from the blood vessel in which the stent graft of the abdominal aortic aneurysm is placed.
(10) The embolic material according to (8) or (9), wherein the embolic body is compressively deformable so as to come into close contact with the side branch blood vessel over the entire circumferential direction.
(11) The embolic material according to (8) or (9), wherein the embolic body is compressible and deformable so as to partially fit into the entrance of the side branch blood vessel.
(12) The embolic material according to any one of (8) to (11), comprising a plurality of embolic bodies of only one type.
(13) An embolic material according to any one of (8) to (11), comprising a plurality of the embolic bodies, the embolic bodies comprising a first embolic body and a second embolic body having a specific gravity greater than that of the first embolic body.
(14) An embolic material according to any one of (8) to (11), wherein the embolic body includes a mass formed integrally of a third embolic body and a fourth embolic body having dimensions different from those of the third embolic body.
(15) The embolic material according to (13), wherein the second embolic body includes a radiopaque material.
(16) The embolic material according to (14), wherein the fourth embolic body includes a radiopaque material.
(17) The embolic material according to (13), wherein the first embolic body contains an air layer therein.
(18) The embolic material according to (14), wherein the third embolic body contains an air layer therein.
(19) The embolic material according to (13), wherein the first embolic body includes a foam.
(20) The embolic material according to (14), wherein the third embolic body includes a foam.

The above-mentioned embolic material according to one aspect of the present invention can prevent or suppress deformation of the stent graft placed in the aneurysm when discharged, and can also prevent or suppress distal embolization of the side branch in the aneurysm.

1 is a diagram showing the configuration of a medical instrument set and a delivery system according to a first embodiment. FIG. 1 is a diagram showing the configuration of an embolic material delivery medical system according to a first embodiment. FIG. 1A to 1C are diagrams showing a state in which an embolic material is loaded into a loading lumen of the embolic material loading catheter according to the first embodiment. FIG. 13 is a diagram showing how an embolic material loading catheter and a delivery catheter are connected. FIG. 13 is a diagram showing the state in which the embolic material is discharged with the embolic material loading catheter and the delivery catheter connected. FIG. 11 is a schematic cross-sectional view showing an example of an engagement portion of a medical instrument set. 7 is a schematic cross-sectional view showing an engaged state of the engagement portion of FIG. 6. 7 is a schematic cross-sectional view of a variation of the delivery catheter of FIG. 6. FIG. 9 is a schematic cross-sectional view showing a state in which an embolic material loading catheter is connected to the delivery catheter shown in FIG. 8 . 1 is a flowchart showing an outline of a procedure using the embolic material delivery medical system according to the first embodiment. FIG. 13 is a diagram showing an example of operation of the embolic material delivery medical system according to the first embodiment, illustrating a state in which a delivery catheter has been delivered into a lump. FIG. 2 is a diagram showing an example of operation of the embolic material delivery medical system according to the first embodiment, illustrating a state in which a stent graft is deployed within the aneurysm. FIG. 11 is a diagram showing an example of operation of the embolic material delivery medical system according to the first embodiment, illustrating the ejection of an embolic material from a delivery catheter. 13 is a diagram showing an example of operation of the embolic material delivery medical system according to the first embodiment, illustrating a state in which the embolic material has been filled into an aneurysm. FIG. This figure shows the state in which embolic material ejected into an aneurysm is positioned at the entrance of a side branch within the aneurysm, and shows a case in which the size of the embolic material is sufficient to enter the side branch. This figure shows the state in which embolic material ejected into an aneurysm is positioned at the entrance of a side branch within the aneurysm, and shows a case in which the size of the embolic material is such that it fits into the entrance of the side branch. This figure shows the state in which embolic material ejected into an aneurysm is positioned at the entrance of a side branch within the aneurysm, and shows a case in which the size of the embolic material is such that it cannot fit into the entrance of the side branch. 13 is a schematic diagram showing an embolic material constituting an embolic material delivery medical system according to a second embodiment placed at the entrance of a side branch. FIG. 13 is a diagram showing the state in which an embolic material constituting an embolic material delivery medical system according to a third embodiment is placed at the entrance of a side branch. FIG. 17 is a diagram showing the state where the embolic material according to the third embodiment is placed at the entrance of a side branch different from that in FIG. 16 . 13 is a diagram showing a state in which an embolic material constituting an embolic material delivery medical system relating to variant 1 of the third embodiment is placed at the entrance of a side branch. FIG. FIG. 13 is a diagram showing an embolic material constituting an embolic material delivery medical system according to a fourth embodiment. 20 is a diagram showing the state in which the embolic material shown in FIG. 19 is housed in a loading lumen of an embolic material loading catheter. FIG. 20 is a diagram showing the state in which the embolus material shown in FIG. 19 is placed at the entrance of a side branch. 20 is a diagram illustrating how the embolic material shown in FIG. 19 is prevented from migrating distally from the entrance of the side branch. FIG. 13 is a diagram showing an embolic material constituting an embolic material delivery medical system according to a first modified example of the fourth embodiment. 24 is a diagram showing the state in which the embolic material shown in FIG. 23 is housed in a loading lumen of an embolic material loading catheter. FIG. 24 is a diagram showing the state in which the embolus material shown in FIG. 23 is placed at the entrance of a side branch. FIG. 1 is a schematic diagram showing an apparatus used in an experiment to evaluate an embolization rate using an embolic material according to one embodiment. FIG. 1 is a schematic diagram showing an apparatus used in an experiment evaluating distal embolization using an embolic material according to one embodiment.

The following describes in detail the embodiments of the present invention with reference to the drawings. The embodiments shown here are illustrative in order to embody the technical ideas of the present invention, and do not limit the present invention. Furthermore, all other possible embodiments, examples, and operational techniques that can be conceived by those skilled in the art without departing from the gist of the present invention are included in the scope and gist of the present invention, and are included in the scope of the inventions described in the claims and their equivalents.

Furthermore, for the convenience of illustration and ease of understanding, the drawings attached to this specification may be represented diagrammatically with appropriate changes in scale, aspect ratio, shape, etc. from the actual product, but these are merely examples and do not limit the interpretation of the present invention.

Figure 1 shows the configuration of a medical instrument set 100 and a delivery system 200 according to the first embodiment, and Figure 2 shows the configuration of an embolic material delivery medical system 300. Figure 3 is a schematic diagram showing the loading of an embolic material 10 into the loading lumen 22 of an embolic material loading catheter 20 according to the first embodiment. Figure 4 is a schematic diagram showing the connection of an embolic material loading catheter 20 and a delivery catheter 40, and Figure 5 is a schematic diagram showing the ejection of an embolic material 10 from a delivery catheter 40. Figure 6 is a schematic cross-sectional view showing an example of an engagement portion 60 of a medical instrument set 100, and Figure 7 is a schematic cross-sectional view showing the engagement state of the engagement portion 60 in Figure 6.

In this specification, the operation direction of each part constituting the embolic material delivery medical system 300 is, for example, along the axial direction of the delivery catheter 40, and the side where the embolic material 10 is delivered into the aneurysm is referred to as the "distal side (or distal end)". The side located axially opposite the distal side and operated by the surgeon (the side where the delivery catheter 40 is removed) is referred to as the "base side (or proximal end)". Note that "distal" refers to a certain range in the axial direction including the most distal end, and "base end" refers to a certain range in the axial direction including the most proximal end.

The medical instrument set 100, the delivery system 200, and the embolic material delivery medical system 300 can be applied to endoleak embolization for stent graft insertion of abdominal aortic aneurysm (AAA), which is a treatment method for preventing the rupture of aneurysms and the like that occur in blood vessels. In addition, the medical instrument set 100, the delivery system 200, and the embolic material delivery medical system 300 can be applied to other interventional therapies for preventing the rupture of aneurysms that occur in blood vessels, in addition to endoleak embolization.

In addition, the delivery system 200 and the embolic material delivery medical system 300 according to this embodiment can also be applied to vascular embolization, which embolizes the blood vessel itself. Examples of vascular embolization include (1) placing an embolizer in the blood vessel before or after an aneurysm to block blood flow to an iliac artery aneurysm or visceral artery aneurysm (renal artery aneurysm, splenic artery aneurysm, hepatic artery aneurysm, etc.), (2) placing an embolizer in the blood vessel to block blood flow to an arteriovenous malformation or arteriovenous fistula, (3) placing an embolizer in the subclavian artery to suppress type II end leaks in stent graft insertion for a thoracic aortic aneurysm, (4) placing an embolizer in the vein to stop blood backflow in pelvic congestion syndrome, (5) placing an embolizer in the blood vessel before the varicose vein to stop blood flow into the varicose vein in varicocele, and (7) placing an embolizer in the blood vessel just before the varicose vein to block blood flow to the cancer lesion. Experiment 2 described below shows that when embolic materials are connected in a ring or line shape, the risk of distal embolization is reduced compared to when embolic materials are used alone, so embolization in (1) to (7) may be possible without the need for anchor coils, etc.

[composition]
Next, the configurations of the medical instrument set 100, delivery system 200, and embolic material delivery medical system 300 according to this embodiment will be described. Fig. 1 shows each device constituting the medical instrument set 100 and delivery system 200 according to this embodiment, and Fig. 2 shows each device constituting the embolic material delivery medical system 300 according to this embodiment.

First, we will explain the medical instrument set 100, delivery system 200, and embolic material 10 used in the embolic material delivery medical system 300 according to this embodiment.

<Embolization material>
The embolic material 10 is placed in a neuropathy such as an aneurysm that occurs in a blood vessel. The embolic material 10 is loaded in the loading lumen 22 of the embolic material loading catheter 20, and is pushed out by the pressure of a fluid injected from the injection device 30 with the distal end of the embolic material loading catheter 20 attached to the delivery catheter 40, and is placed in the neuropathy.

As shown in FIG. 13, the embolic material 10 is formed in a substantially corner-free, approximately spherical shape, and has an embolic body 11 capable of filling the aneurysmal space formed between the abdominal aortic aneurysm and the stent graft. The embolic material 10 is configured such that, when placed in the aneurysm (blood), the dimensions of the sphere, such as the diameter, are equal to or slightly larger than the entrance of the side branch R connected to the abdominal aortic aneurysm. The embolic body 11 is configured to be compressible and deformable so that it can be partially fitted alone into the entrance of the side branch R, which has a diameter of 2 to 5 mm and branches off from the blood vessel in which the stent graft for the abdominal aortic aneurysm is placed. In this embodiment, the embolic body 11 is configured to be in close contact with the side branch R over the entire circumferential direction, and to be compressible and deformable so that it can be partially fitted into the entrance of the side branch R. Here, in the present disclosure, "fitting" refers to at least a part of the embolic body 11 alone penetrating and compressing the side branch R, and then being fixed without being able to penetrate deep inside the side branch (specifically, a part 2 cm or more away from the entrance of the side branch R). This is because the dimensions of the embolus 11 are designed so that the frictional force (engagement force) generated between at least a compressed portion of the embolus 11 and the side branch R is not released by the intravascular pressure. As a result, as described below, the entrance of the side branch R can be closed regardless of which part comes into contact with the side branch. In this embodiment, the embolus material 10 is configured to include multiple emboluses 11 of only one type.

The embolic body 11 of the embolic material 10 can be configured to have a diameter of 4 to 7 mm when filled into the aneurysm space as described below. The embolic body 11 of the embolic material 10 can be configured from an acrylic compound such as polyacrylic acid gel, polyvinyl alcohol gel, hydrogel containing gelatin, porous polyurethane, porous gelatin, silicone rubber, or the like. The embolic body 11 may be configured from an expandable material (such as a water-absorbent gel material) that expands upon contact with aqueous liquids including blood under physiological conditions. Examples of the expandable material include gelatin and a dried hydrogel made of a reaction product of an ethylenically unsaturated monomer and a crosslinking agent. The embolic body 11 may also be configured from these materials to which a visualization agent having X-ray contrast, such as barium, has been added.

Here, "physiological conditions" refers to conditions having at least one environmental characteristic within or on the surface of a mammalian (e.g., human) body. Such characteristics include an isotonic environment, a pH buffer environment, an aqueous environment, a pH near neutral (about 7), or a combination thereof. In addition, "aqueous liquid" includes, for example, isotonic liquid, water; and mammalian (e.g., human) body fluids such as blood, cerebrospinal fluid, plasma, serum, vitreous humor, and urine. As an example of the dimensions of the embolic material 10, it can be configured to have a diameter of approximately φ3 to 8 mm in blood released into the aneurysm from the delivery catheter 40 described below. Here, the above-mentioned dimensions of the embolic material 10 in blood refer to the dimensions when the embolic material absorbs blood and swells, and also include the dimensions when the embolic material absorbs a liquid with an osmotic pressure equivalent to that of blood and swells.

<Medical instrument set>
Next, a description will be given of the configuration of the medical instrument set 100 according to this embodiment. As shown in FIG.

<Catheter for loading embolic material>
The embolic material loading catheter 20 includes a long catheter body 21 having a loading lumen 22 provided therein, and a base end hub 23 provided on the base end side of the catheter body 21. The embolic material loading catheter 20 includes a flexible tube 24 having one end connected to the base end side of the base end hub 23 and the other end connected to a port 26 of a stopcock 25 such as a three-way stopcock.

The catheter body 21 is a tubular member having a hole (loading lumen 22) that communicates from the tip opening 27b to the base opening along the axial direction. The length of the catheter body 21 in the extension direction (longitudinal direction) is set appropriately, but it is sufficient that the catheter body 21 is at least long enough to accommodate the embolic material 10.

The inner diameter of the loading lumen 22 is designed to be approximately equal to the inner diameter of the sheath lumen 42 of the delivery catheter 40. This allows the embolic material 10 to move smoothly from the loading lumen 22 to the sheath lumen 42 together with a liquid such as physiological saline. The dimensions of the loading lumen 22 can be, for example, φ1.0 to 6.0 mm (3 Fr to 18 Fr).

The catheter 20 for loading embolic material is provided in a state where the embolic material 10 is already loaded. However, as shown in FIG. 3, the surgeon may use an injection tool 30 (described later) to suck up the embolic material 10 mixed in liquid from a separate container V such as an ampule, and load it from the tip connection part 27 into the loading lumen 22 of the catheter body 21.

The catheter body 21 is attached by engaging with the sheath hub 43 of the delivery catheter 40 with the embolic material 10 stored therein by the engagement portion 60 described below. In this attached state, the loaded embolic material 10 is pushed out toward the delivery catheter 40 by moving the pusher body 32 of the injection tool 30 toward the tip.

Since the embolic material loading catheter 20 is not inserted into the sheath of the delivery catheter 40, it does not need to be flexible enough to follow the curved shape of the biological lumen during insertion. Therefore, the material of the catheter body 21 is not particularly limited as long as it is at least more rigid than the delivery catheter 40 and has a moderate hardness that prevents damage to the embolic material 10 loaded during packaging, etc. Examples of materials that can be used for the catheter body 21 include polymer materials such as polyolefins (e.g., polyethylene, polypropylene, polybutene, ethylene-propylene copolymers, ethylene-vinyl acetate copolymers, ionomers, or mixtures of two or more of these), polyolefin elastomers, crosslinked polyolefins, polyvinyl chloride, polyamides, polyamide elastomers, polyesters, polyester elastomers, polyurethanes, polyurethane elastomers, fluorine-based resins, polycarbonates, polystyrenes, polyacetals, polyimides, polyetherimides, and aromatic polyether ketones, or resin materials such as mixtures of these. In addition, to provide contrast and improve mechanical strength, these resin materials may be mixed with metal materials such as shape memory alloys, stainless steel, tantalum, titanium, platinum, gold, and tungsten.

The catheter body 21 only needs to be more rigid than the sheath 41 in order to prevent damage to the embolic material 10. In addition to using a hard material, the catheter body 21 may be made thicker when using the same material as the sheath 41 to prevent kinking. In the case of a variable thickness catheter body 21, the outer diameter of the catheter body 21 will be larger than the outer diameter of the sheath 41, but this does not pose a problem because the embolic material loading catheter 20 is attached to the delivery catheter 40 via the engagement portion 60.

The base end hub 23 is an intermediate member that has an insertion passage 23a (lumen) that connects the loading lumen 22 of the catheter body 21 to the tube 24, and allows the fluid (such as physiological saline for priming) flowing in from the stopcock 25 to flow through the catheter body 21 via the tube 24. The embolic material 10 loaded into the loading lumen 22 moves toward the delivery catheter 40 by flowing through the loading lumen 22 via the insertion passage 23a of the base end hub 23 using the injection tool 30.

The material of the base end hub 23 is not particularly limited as long as it is a hard material such as a hard resin. Examples of materials that can be used to form the base end hub 23 include polyolefins such as polyethylene and polypropylene, polyamides, polycarbonates, and polystyrene.

A hemostatic valve (not shown) is attached to the inside of the base end side of the base end hub 23. The hemostatic valve may be a substantially elliptical membrane-shaped (disk-shaped) valve body made of an elastic material such as silicone rubber, latex rubber, butyl rubber, or isoprene rubber.

One end of the tube 24 is connected to the base end side of the base end hub 23, and the other end is connected to the port 26 of the stopcock 25. The tube 24 is a conduit through which liquid such as saline flows out of the priming syringe connected to the port 26.

The tube 24 is not particularly limited as long as it is made of a resin material that is flexible and allows for ease of use. Examples of suitable materials for the tube 24 include polyolefins such as polyethylene, polypropylene, and ethylene-propylene copolymers, polyesters such as polyethylene terephthalate, polystyrene, and polyvinyl chloride.

The stopcock 25 communicates with the insertion passage 23a of the base end hub 23 and the loading lumen 22 of the catheter body 21 via the tube 24. The base end side of the tube 24 can be connected to the port 26 of the stopcock 25, and a priming syringe for priming the loading lumen 22 of the catheter body 21 can also be connected.

As shown in FIG. 6, the distal end of the embolic material loading catheter 20 is provided with a distal end connection portion 27 that is connected to the sheath hub 43 of the delivery catheter 40. The distal end connection portion 27 is provided with a second engagement portion 28 that engages with a first engagement portion 48 that is provided on the proximal end of the sheath hub 43.

In the medical instrument set 100 according to this embodiment, the first engagement portion 48 and the second engagement portion 28 constitute an engagement portion 60 for maintaining the connection between the embolic material loading catheter 20 and the delivery catheter 40.

Figures 6 and 7 show examples of the engagement portion 60. In the engagement portion 60, the first engagement portion 48 functions as a female portion, and the second engagement portion 28 functions as a male portion.

As shown in FIG. 7, the engagement portion 60 may be configured so that the embolic material loading catheter 20 fits externally to the delivery catheter 40. In this configuration, the first engagement portion 48 has a groove portion 48a provided along the circumferential direction on the outer peripheral surface of the base end side of the sheath hub 43. The second engagement portion 28 is provided as a separate skirt member fixed on the outer peripheral surface of the tip portion of the catheter body 21, and has a plurality of engagement claws 28a provided so as to cover at least a part of the outer periphery of the tip portion of the catheter body 21. As shown in FIG. 7, the engagement portion 60 maintains the connection state between the embolic material loading catheter 20 and the delivery catheter 40 by fitting the engagement claws 28a of the second engagement portion 28 into the groove portion 48 that becomes the first engagement portion 48. When the embolic material loading catheter 20 and the delivery catheter 40 are connected, the loading lumen 22 and the sheath lumen 42 are communicated.

The engagement portion 60 is not limited to the fitting configuration shown in Figs. 6 and 7, and other connection configurations such as a screw-in type may be adopted as long as the connection between the embolic material loading catheter 20 and the delivery catheter 40 is maintained. The engagement portion 60 is configured to maintain the attachment state between the embolic material loading catheter 20 and the delivery catheter 40, and prevents the attachment state between the two catheters from coming loose during the procedure. However, the embolic material loading catheter 20 and the delivery catheter 40 do not necessarily have to be engaged via the engagement portion 60. For example, the state in which the tip connection portion 27 is inserted into the sheath hub 43 may be the attachment state between the embolic material loading catheter 20 and the delivery catheter 40.

The tip connection section 27 has an insertion section 27a that is inserted into the communicating enlarged diameter section 43c provided inside the sheath hub 43 when the embolic material loading catheter 20 and the delivery catheter 40 are in a connected state. When the embolic material loading catheter 20 and the delivery catheter 40 are in a connected state, the insertion section 27a is inserted into the sheath hub 43 so that the loading lumen 22 and the sheath lumen 42 are aligned in the axial direction. This allows the embolic material 10 to be pushed out from the loading lumen 22 through the sheath hub 43 into the sheath lumen 42 without being exposed to the outside.

In addition, the insertion section 27a has a tip abutment portion at the tip opening 27b that abuts against the inner surface of the tapered portion 43d provided in the communicating expanded portion 43c at its tip side when the embolic material loading catheter 20 and the delivery catheter 40 are connected. When the insertion section 27a is inserted into the communicating expanded portion 43c, the tip abutment portion abuts against the tapered portion 43d, so that the loading lumen 22 and the sheath lumen 42 communicate with each other without intersecting with other spaces including the space of the communicating expanded portion 43c. Therefore, when the embolic material 10 is pushed out from the embolic material loading catheter 20 into the delivery catheter 40, damage due to contact with the inner wall surface of the sheath hub 43 is prevented. In addition, erroneous insertion into other spaces in the sheath hub 43 (such as getting lost in the tube 44 connected to the sheath hub 43) is prevented, and the embolic material is reliably delivered to the sheath lumen 42.

Injection equipment
The injection device 30 is used when loading the embolic material 10 into the loading lumen 22, or when delivering the embolic material 10 from the loading lumen 22 to the inside of the aneurysm via the sheath lumen 42 of the delivery catheter 40. The injection device 30 includes a syringe 31, a pusher body 32, and a seal member 33, as shown in FIG.

The syringe 31 has a space capable of containing a liquid such as saline or contrast agent for loading the embolic material 10 into the loading lumen 22 of the embolic material loading catheter 20, or for moving the embolic material 10 from the loading lumen 22 to the sheath lumen 42 of the delivery catheter 40. The internal space of the syringe 31 can contain a liquid such as saline or contrast agent together with the embolic material 10.

The pusher body 32 is configured so that at least a portion thereof can move within the internal space of the syringe 31 so that the embolic material 10 can be moved in and out of the loading lumen 22 by acting on the fluid in the internal space of the syringe 31. A portion of the pusher body 32 is exposed to the outside from the internal space of the syringe 31, and the user can use the exposed portion as a handle.

The sealing member 33 is integral with the pusher body 32 at the tip side of the portion located in the internal space of the pusher body 32, and prevents the fluid present in the internal space of the syringe 31 from leaking out of the pusher body 32 to the outside.

When the pusher body 32 is moved so that the internal space of the syringe 31 increases, a negative pressure is generated, and the embolic material 10 that has come into contact with the liquid can be loaded into the loading lumen 22 of the embolic material loading catheter 20. The pusher body 32 also moves the syringe 31 so that the internal space decreases while the embolic material 10 that has come into contact with the liquid is loaded into the loading lumen 22. This allows the embolic material 10 loaded into the loading lumen 22 to be moved by liquid pressure (water pressure) toward the sheath lumen 42 of the delivery catheter 40.

The materials for the syringe 31 and the pusher body 32 are not particularly limited as long as they are suitable for providing the appropriate hardness and flexibility for transporting the embolic material 10. Examples of materials for the syringe 31 and the pusher body 32 include polyolefins (e.g., polyethylene, polypropylene, polybutene, ethylene-propylene copolymers, ethylene-vinyl acetate copolymers, ionomers, or mixtures of two or more of these), polyolefin elastomers, crosslinked polyolefins, polyvinyl chloride, polyamides, polyamide elastomers, polyesters, polyester elastomers, polyurethanes, polyurethane elastomers, fluororesins such as ETFE, polymeric materials such as polycarbonates, polystyrenes, polyacetals, polyimides, polyetherimides, and aromatic polyether ketones, or mixtures thereof, resin materials, shape memory alloys, and metal materials such as stainless steel, tantalum, titanium, platinum, gold, and tungsten. The materials for the seal member 33 are not particularly limited, and examples include natural rubber, silicone rubber, nitrile rubber, and fluororubber.

<Delivery system>
Next, a description will be given of a delivery system 200 according to this embodiment. As shown in Fig. 1, the delivery system 200 according to this embodiment includes, in addition to a medical instrument set 100, a delivery catheter 40 to which an embolic material loading catheter 20 is attached and detached while the delivery system is placed in a living body lumen.

The delivery catheter 40 can be, for example, an existing catheter that can be placed in a biological lumen. Therefore, in the delivery system 200 according to this embodiment, the medical instrument set 100 and the delivery catheter 40 can be sold as a set and supplied to the market. Even if only the medical instrument set 100 is sold and supplied to the market, it is possible to make the delivery system 200 function by using an existing catheter as the delivery catheter 40.

Delivery Catheter
The delivery catheter 40 includes a sheath 41 made of a long tubular member having a hole (sheath lumen 42) that communicates from an opening on the tip side to an opening on the base side along the axial direction, for example. The delivery catheter 40 is placed in a biological lumen and functions as an introduction path for delivering the embolic material 10 to the inside of the aneurysm. A main body 51 of an insertion assist member 50, which will be described later, can be inserted through the sheath 41 over its entire length. Therefore, the axial length of the sheath 41 is set to be at least shorter than the main body 51 of the insertion assist member 50.

The inner diameter of the sheath lumen 42 can be configured to be approximately equal to or smaller than the inner diameter of the loading lumen 22. For example, the dimensions of the sheath lumen 42 can be configured to be φ1.0 mm to 3.5 mm (3 Fr to 10 Fr). This allows the embolic material 10 to be moved smoothly from the loading lumen 22 to the sheath lumen 42 when the embolic material loading catheter 20 and the delivery catheter 40 are connected by the engagement portion 60.

The material of the sheath 41 is not particularly limited as long as it has flexibility and rigidity to a degree that allows it to follow the curved shape of the biological lumen, such as meandering or curvature. Examples of materials that can be suitably used for the sheath 41 include polymer materials such as polyolefin (e.g., polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or a mixture of two or more of these), polyolefin elastomer, crosslinked polyolefin, polyvinyl chloride, polyamide, polyamide elastomer, polyester, polyester elastomer, polyurethane, polyurethane elastomer, fluorine-based resin, polycarbonate, polystyrene, polyacetal, polyimide, polyetherimide, aromatic polyether ketone, or resin materials such as mixtures of these.

The delivery catheter 40 also includes a sheath hub 43 that is connected to the base end of the sheath 41, and a flexible tube 44 that is connected at one end to the base end of the sheath hub 43 and at the other end to a stopcock 45 such as a three-way stopcock.

The sheath hub 43 has a communication passage 43a that communicates between the sheath lumen 42 and the tube 44, and between the loading lumen 22 and the sheath lumen 42 (see FIG. 6). The sheath hub 43 is an intermediate member that allows the fluid (such as physiological saline for priming) flowing in from the stopcock 45 to flow through the tube 44 to the sheath 41, and also guides the embolic material 10 pushed out from the embolic material loading catheter 20 into the sheath lumen 42. The insertion assist member 50 is inserted into the sheath hub 43 when the delivery catheter 40 is placed in the biological lumen.

The sheath hub 43 may be made of the same material as the base end hub 23 described above.

The communication passage 43a has a communication tip 43b having an inner diameter approximately equal to the diameter of the sheath lumen 42, and a communication enlarged diameter portion 43c that extends from the communication tip 43b in the proximal direction and has an internal space with a larger diameter than the communication tip 43b. In addition, at the connection portion between the communication enlarged diameter portion 43c and the communication tip 43b, a tapered portion 43d is provided that expands in diameter in the proximal direction from the opening on the proximal side of the communication tip 43b.

When the embolic material loading catheter 20 and the delivery catheter 40 are attached, the tip of the loading lumen 22 is inserted so that it is adjacent to the opening on the base end side of the communicating tip portion 43b. This allows the embolic material 10 to be delivered from the loading lumen 22 to the sheath lumen 42 without being exposed to the outside when it is pushed out from the embolic material loading catheter 20 into the delivery catheter 40.

The insertion state of the insertion section 27a is preferably such that the inner surface of the tapered section 43d and the abutting section of the tip opening 27b abut against each other so that the loading lumen 22 and the sheath lumen 42 are aligned in the axial direction. This allows the tip of the insertion section 27a and the base end side opening of the communicating tip section 43b to be continuous along the axial direction, preventing damage (crushing of the tip side) caused by the extruded embolic material 10 hitting the inner wall surface of the sheath hub 43. In addition, the loading lumen 22 and the sheath lumen 42 are communicated so as not to intersect with the space in the communicating expanded diameter section 43c, preventing erroneous insertion into other spaces in the sheath hub 43 (such as getting lost in the tube 44 connected to the sheath hub 43).

The delivery catheter 40 is configured so that it can be connected to the embolic material loading catheter 20 at the sheath hub 43 located on the base end side. As shown in Figures 6 and 7, the base end side of the sheath hub 43 is provided with a first engagement portion 48 that engages with the second engagement portion 28 provided on the tip connection portion 27 of the embolic material loading catheter 20.

The first engagement portion 48 may be configured, for example, as a groove portion 48a into which the engagement claw 28a of the second engagement portion 28 described above is fitted. The groove portion 48a is provided along the circumferential direction of the outer peripheral surface at the base end side of the sheath hub 43 in FIG. 6.

One end of the tube 44 is connected to the base end side of the sheath hub 43, and the other end is connected to the port 46 of the stopcock 45. The tube 44 is a conduit through which liquid such as physiological saline flows out of a priming syringe (not shown) connected to the port 46. The material constituting the tube 44 can be the same as the material exemplified above for the tube.

The stopcock 45 communicates with the communication passage 43a of the sheath hub 43 and the sheath lumen 42 of the sheath 41 via the tube 44. The base end of the tube 44 can be connected to the port 46 of the stopcock 45, and a priming syringe for priming the sheath lumen 42 of the sheath 41 and a liquid injection syringe for injecting a contrast agent or a drug can also be connected.

A hemostatic valve 47 is attached to the inside of the base end side of the sheath hub 43. The hemostatic valve 47 may be a substantially elliptical membrane-shaped (disk-shaped) valve body made of, for example, an elastic material such as silicone rubber, latex rubber, butyl rubber, or isoprene rubber. When the embolic material loading catheter 20 is attached to the delivery catheter 40, at least the abutting portion of the tip opening 27b of the insertion section 27a passes through the hemostatic valve 47 and is inserted into the communicating expanded diameter section 43c.

Here, we will explain examples of dimensions of the parts of each device constituting the delivery system 200 according to this embodiment that are related to the embolic material and are not limited to the parts mentioned above. Note that the values shown below are only examples and are not limited to these.

In the delivery system 200, the delivery catheter 40 can be a catheter with an inner diameter of 6 Fr. Furthermore, when the procedure to be applied is endoleak embolization for stent graft insertion for abdominal aortic aneurysm (AAA), the body length of the catheter body 21 of the embolic material loading catheter 20 can be configured to be 30 to 105 cm (preferably about 42 cm). Furthermore, the body length of the sheath 41 of the delivery catheter 40 can be 39 to 90 cm (preferably about 70 cm).

<Embolization material delivery medical system>
Next, a description will be given of the configuration of the embolic material delivery medical system 300 according to this embodiment. As shown in Fig. 2, the embolic material delivery medical system 300 according to this embodiment includes, in addition to the delivery system 200, an insertion assist member 50 for delivering the delivery catheter 40 into a biological lumen.

<Insertion aid>
The insertion assistance member 50 is an auxiliary tool that has a guidewire lumen 52 that passes from the tip end to the base end along the axial direction of the main body 51, and that assists in the insertion of the delivery catheter 40 into the aneurysm along a guidewire that has been previously inserted into the biological lumen.

The insertion assistance member 50 is inserted into and assembled with the delivery catheter 40 to prevent bending or the like when the delivery catheter 40 is inserted into the biological lumen. The guidewire lumen 52 has a smaller inner diameter than the sheath lumen 42 of the delivery catheter 40. This makes it possible to reduce the axial misalignment of the delivery catheter 40 with respect to the guidewire when delivering the delivery catheter 40 into the aneurysm, making delivery easier.

The material of the insertion assist member 50 is not particularly limited as long as it is harder and more flexible than the delivery catheter 40. Examples of suitable materials for the insertion assist member 50 include polyolefins such as polyethylene and polypropylene, polyesters such as polyamide and polyethylene terephthalate, fluororesins such as ETFE, PEEK (polyether ether ketone), and polyimide, as well as metal materials such as shape memory alloys, stainless steel, tantalum, titanium, platinum, gold, and tungsten.

[motion]
Next, the operation of the embolic material delivery medical system 300 according to this embodiment will be described with reference to Figures 10 to 14 as appropriate. Figure 10 is a flow chart showing an outline of a procedure using the embolic material delivery medical system 300 according to the first embodiment. Figure 11A is an example of operation of the embolic material delivery medical system 300 according to the first embodiment, showing a state in which the delivery catheter 40 has been delivered into the aneurysm. Figure 11B is a view showing a state in which the stent graft SG has been deployed within the aneurysm. Figure 11C is a view showing the state in which the embolic material 10 is discharged from the delivery catheter 40. Figure 11D is a view showing the state in which the embolic material 10 has been filled into the aneurysm.

Figure 12 shows the state where embolic material G1 discharged into the aneurysm is located at the entrance of a side branch R in the aneurysm, and shows a case where the size of embolic material G1 is such that it can enter the side branch R. Figure 13 shows the state where embolic material 10 discharged into the aneurysm is located at the entrance of a side branch R in the aneurysm, and shows a case where the size of embolic material 10 is such that it can fit into the entrance of the side branch R. Figure 14 shows the state where embolic material G2 discharged into the aneurysm is located at the entrance of a side branch R in the aneurysm, and shows a case where the size of embolic material G2 is such that it cannot fit into the entrance of the side branch R.

Here, we will explain an example of the operation of the embolic material delivery medical system 300 when applied to endoleak embolization for stent graft insertion surgery for abdominal aortic aneurysm (AAA).

To summarize the method of using the embolic material delivery medical system 300 with reference to Figure 7, the surgeon measures the vascular diameter of the side branch R branching off from the abdominal aortic aneurysm (S1) and moves the tip opening 41a of the delivery catheter 40 to the abdominal aortic aneurysm (S2). The surgeon then places the stent graft SG in the abdominal aortic aneurysm (S3) and ejects the embolic material 10 into the aneurysm space between the abdominal aortic aneurysm and the stent graft SG (S4). This will be described in more detail below.

First, as a preparation step, the surgeon measures the dimensions of the side branch R branching off from the abdominal aortic aneurysm to be treated by the procedure using a CT (Computed Tomography) or the like to determine the dimensions of the embolic material 10 to be used in the procedure (S1). The size of the embolic material 10 to be used in the procedure varies depending on the size of the IMA and LA, but as described above, the size in the blood is generally in the range of 3-8 mm. In addition, the embolic material 10 can be considered to be a value of about 2 mm added to the blood vessel diameter of the side branch R, and in the case of an embolic material in which an embolic body capable of controlling distal embolization is connected in a ring or line shape, the value can be considered to be a value of about 0.5 mm added to the blood vessel diameter of the side branch R. When selecting one type from multiple embolic materials with different dimensions, the surgeon can select an embolic material whose minimum value, including variations, is larger than the measured blood vessel diameter.

Next, the surgeon prepares the embolic material loading catheter 20, the injection device 30, the delivery catheter 40, the insertion assisting member 50, and the like. At this stage, the embolic material 10 can be in a compressed state or in its original shape and filled in the loading lumen 22 of the embolic material loading catheter 20. Then, as shown in FIG. 11A, the surgeon inserts the sheath 41 of the delivery catheter 40, into which the insertion assisting member 50 is inserted, percutaneously into the biological lumen through an introducer from the patient's limb that is the puncture site. Then, the distal end opening 41a of the delivery catheter 40 is delivered to the abdominal aortic aneurysm (S2). When the distal end opening 41a is delivered to the inside of the aneurysm, the insertion assisting member 50 is removed. The delivery catheter 40 may be delivered to the aneurysmal site using a guide wire previously inserted into the aneurysm without using the insertion assisting member 50. In addition, the delivery catheter 40 and the embolic material loading catheter 20 are primed with a liquid such as saline before being introduced into the body lumen.

Next, as shown in FIG. 11B, the surgeon inserts a catheter (stent graft delivery device) with the stent graft SG compressed and inserted through an introducer into the biological lumen, and moves it to the affected part of the aneurysm using a guide wire previously inserted into the aneurysm. After that, the stent graft SG is deployed from the catheter at the affected part and placed in place (S3). As a result, as shown in FIG. 11B, the delivery catheter 40 is inserted between the leg of the stent graft SG and the blood vessel wall of the aneurysm, with the tip of the delivery catheter 40 being inserted between the stent graft SG and the blood vessel wall of the aneurysm, i.e., into the aneurysm. As a result, the delivery catheter 40 is placed in the biological lumen with the tip opening 41a located within the aneurysm. Alternatively, the delivery catheter 40 may be inserted into the aneurysm along the guide wire previously inserted into the aneurysm after the stent graft SG is deployed, so that the tip opening 41a is placed in the biological lumen.

When the delivery catheter 40 is placed, the surgeon attaches (connects) the tip connection portion 27 of the embolic material loading catheter 20 to the base end of the sheath hub 43 of the delivery catheter 40, as shown in Figures 4 and 7. At this time, as shown in Figure 7, the abutment portion of the tip opening 27b is inserted into the communicating expanded portion 43c of the sheath hub 43 and abuts against the inner surface of the tapered portion 43d. As a result, the tip of the loading lumen 22 is adjacent to the communicating tip portion 43b, and the axes of the loading lumen 22 and the sheath lumen 42 are aligned.

Next, as shown in FIG. 5, the surgeon moves the pusher body 32 so as to reduce the internal space of the syringe 31 of the injection device 30. As a result, the embolic material 10 loaded in the embolic material loading catheter 20 moves toward the tip together with the liquid such as physiological saline, and the embolic material 10 moves as if being pushed out into the sheath lumen 42 of the delivery catheter 40 by the pushing operation (S4). Since the sheath lumen 42 of the delivery catheter 40 is configured to be equal to or smaller than the inner diameter of the loading lumen 22 of the embolic material loading catheter 20, the embolic material 10 may be compressed and deformed when moving from the loading lumen 22 to the sheath lumen 42.

Then, as shown in FIG. 11C, the surgeon pushes out the embolic material 10 from the sheath lumen 42 into the aneurysm by pushing out the injection tool 30 (S4). When the embolic material 10 moves from the sheath lumen 42 into the aneurysm, it is released from compression and returns to its original shape, becoming the same size as the side branch R or slightly thicker than the side branch R. If the embolic body 11 is made of an expandable material, the embolic material 10 expands in the aneurysm upon contact with a liquid such as saline or blood, becoming the same size as the side branch R or slightly thicker than the side branch R. After that, the surgeon detaches the empty embolic material loading catheter 20 together with the injection tool 30 from the delivery catheter 40. The injection tool 30 can be detached from the delivery catheter 40 while still inserted in the embolic material loading catheter 20. This completes the first insertion operation of the embolic material 10 into the aneurysm. In addition, in the insertion operation, the injection tool 30 may be removed from the embolic material loading catheter 20 before the detachment operation of the embolic material loading catheter 20. The series of embolic material placement operations shown in Fig. 11C to Fig. 11D is repeated until the required amount of embolic material 10 is loaded into the aneurysm. The required amount is calculated by calculating the volume of the aneurysm based on the CT data of the patient and subtracting from that value the volume of the stent graft SG when deployed in the aneurysm. This required amount may be used as a guideline for the actual embolic material placement operation. Specifically, during the embolic material placement operation, the filling status of the embolic material may be confirmed by X-ray, and the placement of the embolic material may be terminated when it is confirmed by X-ray contrast images that the blood flow to the side branch R has been blocked.

When the required amount of embolic material 10 has been placed in the aneurysm, the surgeon withdraws the delivery catheter 40 from within the aneurysm and the biological lumen. Alternatively, before withdrawing the delivery catheter 40 from within the aneurysm and the biological lumen, the surgeon may detach the embolic material loading catheter 20 from the delivery catheter 40 after detaching the injection device 30 from the embolic material loading catheter 20. In either case, the introducer is left in place in the biological lumen for further expansion of the stent graft SG with a balloon after placement of the embolic material 10, contrast manipulation, and the like.

The embolic material 10 placed in the aneurysm can move from the tip of the delivery catheter 40 toward the entrance of the side branch R located in the aneurysm due to the blood flow in the aneurysm. In the case of a stent graft SG using a water-permeable base material such as polyester, blood flows from the aorta side into the aneurysm and from the aneurysm toward the side branch R immediately after the stent graft SG is placed. In the case of a stent graft SG using a water-impermeable base material such as ePTFE, there is no blood flow from the aorta side into the aneurysm, but a flow from the aneurysm toward the side branch R can be created by injecting physiological saline or the like from the delivery catheter 40. Here, the embolic body 11 of the embolic material 10 is configured to have a diameter slightly larger than the blood vessel diameter of the side branch R and is configured to be compressible and deformable, so that it is positioned so as to fit into the side branch R at the entrance of the side branch R as shown in FIG. 13. This allows the embolic material 10 to block the flow path between the inside of the aneurysm and the side branch R, enabling embolization, and also prevents distal embolization from penetrating into the inside of the side branch R to a position far away from the inside of the aneurysm. Furthermore, by filling the space between the inner surface of the aneurysm and the outer surface of the stent graft SG, the embolic material 10 is less likely to come off the entrance of the side branch R even when backflow occurs from the side branch R, and the occlusion within the aneurysm is maintained. This prevents the aneurysm from expanding or bursting. Note that when the embolic body 11 of the embolic material 10 is made of an expandable material, the embolic body 11 swells upon contact with liquid such as blood within the aneurysm, making its diameter somewhat larger than the diameter of the side branch R, and it is compressed and deformed to fit into the side branch R at the entrance.

In stent graft insertion for abdominal aortic aneurysm, backflow from the side branch into the aneurysm (type 2 endoleak) may occur after placement of the stent graft, so an embolic material is used to block blood flow into the aortic aneurysm. Long embolic materials have been used in the past. In order to block blood flow using a long embolic material, it is thought that the embolic material is filled in excess of the aneurysm volume, so that a part of the swollen embolic material closes the entrance of the side branch of the aortic aneurysm and stops blood flow from the side branch. The inventors have found that when the embolic material is filled into the aneurysm space with a stent graft placed in an abdominal aortic aneurysm, if the embolic material is long, the stent graft may be deformed so as to be crushed by the long embolic material depending on the degree of filling. In other words, the inventors have found that when the embolic material is long, the crushing of the stent graft tends to gradually increase as the embolization rate of the side branch increases. Conversely, if a small amount of long embolic material is used to avoid crushing the stent graft, a gap will remain between the side branch and the embolic material, and there is a risk that the embolic material will not be able to stop the blood flow between the abdominal aortic aneurysm and the side branch R. In other words, it was found that if a long embolic material is used to prevent the stent graft from collapsing, the embolization rate of the side branch will also be reduced.

In this embodiment, the embolic material 10 has an embolic body 11 that is formed in a substantially spherical shape and can be filled into the aneurysmal space formed between the abdominal aortic aneurysm and the stent graft SG. The embolic body 11 is configured to be compressible and deformable so that it can fit alone into a side branch R with a diameter of 2 to 5 mm that branches off from the blood vessel in which the stent graft SG for the abdominal aortic aneurysm is placed. The embolic body 11d can be configured to have a diameter of 4 to 7 mm when filled into the aneurysmal space.

In this way, by forming the embolic body 11 in a substantially spherical shape, the degree of freedom of movement is increased compared to when the embolic material is long, and the embolic body 11 can be carried along by the blood flow to the entrance of the side branch R. Also, as shown in FIG. 12, if the embolic material G1 is smaller than the diameter of the entrance of the side branch R or is too soft, distal embolism occurs or is likely to occur. On the other hand, as shown in FIG. 14, if the embolic body of the embolic material G2 is too large or too hard for the entrance of the side branch R, the probability of the spherical side surface being positioned at the entrance of the side branch R is reduced, or the degree of adhesion with the side branch R is weakened. As a result, there is a risk that the effect of preventing blood flow to the abdominal aortic aneurysm is insufficient. In contrast, in this embodiment, the embolic body 11 of the embolic material 10 is configured to be compressible and deformable to a size that fits into the entrance of the side branch R. Therefore, by having appropriate dimensions and hardness at the entrance of the side branch R when filling the aortic aneurysm, it can be tightly attached to the entrance of the side branch R, preventing or suppressing the crushing of the stent graft SG, and preventing or suppressing the occurrence of distal embolism. Also, by forming the embolic body 11 of the embolic material 10 into a substantially spherical shape, it is possible to efficiently close the entrance of the side branch R even if the filling rate of the aortic aneurysm is 100% or less, and the effectiveness of side branch closure can be improved without crushing the stent graft SG.

The embolus body 11 is also configured to be compressible and deformable so as to be in close contact with the side branch R over the entire circumferential direction. With this configuration, even if the embolus body 11 attempts to enter the distal side from the entrance of the side branch R, the embolus body 11 is in close contact over the entire circumferential direction, so that the entry resistance of the embolus material 10 is relatively high. Therefore, the embolus material 10 is prevented from moving distally, and the occurrence of distal embolism can be prevented or suppressed.

The embolus body 11 is also configured to be compressible and deformable so that it partially fits into the entrance of the side branch R. By fitting the embolus body 11 into the entrance of the side branch R in this way, the embolus body 11 cannot move any further distally, thereby preventing the embolus material 10 from moving distally and preventing or suppressing the occurrence of distal embolism.

In addition, in this embodiment, the embolic material 10 is configured to include only one type of embolic body 11. This configuration can prevent or suppress the above-mentioned stent graft SG from being crushed, and can also prevent the occurrence of distal embolism.

Second Embodiment
Fig. 15 is a diagram showing the second embodiment of the embolic material 10a placed in an abdominal aortic aneurysm. In the first embodiment, the embolic body 11 constituting the embolic material 10 is only one type, but the type of embolic body does not have to be only one type. That is, the embolic material 10a can be configured to include multiple types of embolic bodies, such as a first embolic body 11a and a second embolic body 12a shown in Fig. 15.

The first embolus 11a and the second embolus 12a are configured to have a different specific gravity, and the second embolus 12a is configured to have a smaller volume than the first embolus 11a but a larger specific gravity than the first embolus 11a. There are no particular limitations on the method of setting the specific gravity, but if the specific gravity of blood is around 1.05 (1.04 to 1.06), the specific gravity of the first embolus 11a can be set to 1.0 or less and the specific gravity of the second embolus 12a can be set to 1.1 or more. The first embolus 11a and the second embolus 12a can be compressed and inserted into the sheath lumen 42 of the delivery catheter 40, as in the first embodiment.

The specific gravity of the first embolus 11a can be made smaller than that of the second embolus 12a by providing an air layer (cavity) inside the sphere (interior) or by making the embolus into a sponge structure (foam) such as an open-cell structure or closed-cell structure. The specific gravity of the first embolus 11a can be made smaller than that of the second embolus 12a by adding carbon dioxide to the liquid that swells the embolus material and causing bubbles to adhere around the embolus material. The specific gravity of the first embolus 11a can be made smaller than that of the second embolus 12a by threading a multifilament thread through the embolus material to form small bubbles within the filament.

The second embolic body 12a can have a higher specific gravity than the first embolic body 11a by impregnating the embolic material with a contrast agent containing a radiopaque material such as barium sulfate, by impregnating the embolic material with metal particles, or by passing a metal coil through the embolic material. When the embolic material contains barium sulfate or metal particles, the embolic body can be visualized when a contrast image is used.

The side branches R extending from the abdominal aortic aneurysm mainly include the inferior mesenteric artery (IMA) and the lumbar artery (LA). The IMA is located on the ventral side of the aneurysm and has a relatively large diameter at the entrance of the side branch R (diameter dr1), while the LA has a relatively small diameter at the entrance of the side branch R (diameter dr2, see Figure 15) and is located on the dorsal side. In addition, there is a high possibility that the patient will be lying on his back during the procedure. Among the above-mentioned end leaks, type 2 end leaks are end leaks associated with backflow from the side branches of the aortic aneurysm, and in order to prevent or suppress this, it is more preferable to place an embolic material of a size that varies depending on the size of the side branch R, such as the IMA or LA.

As described above, by configuring the embolic material 10a to include the first embolic body 11a and the second embolic body 12a, the first embolic body 11a (diameter dg1), which has a small specific gravity and a large volume, can be placed in the IMA. Also, the second embolic body 12a (diameter dg2), which has a large specific gravity and a small volume, can be placed in the LA.

By preparing two types of embolization bodies with different sizes and specific gravities, it is possible to efficiently embolize the side branches R, such as the IMA and LA, without filling the entire aneurysm with approximately spherical embolization material. In addition, by preparing multiple types of embolization bodies, such as the first embolization body 11a and the second embolization body 12a, it is possible to place an embolization body of an appropriate size at the entrance of the side branch R depending on the blood vessel diameter.

The configuration of the embolic material delivery medical system other than the embolic material and the treatment method using the embolic material delivery medical system are the same as those in the first embodiment, so the explanation will be omitted.

As described above, in this embodiment, the embolic body is configured to include a first embolic body 11a and a second embolic body 12a having a larger specific gravity than the first embolic body 11a. With this configuration, the first embolic body 11a and the second embolic body 12a can be placed at different locations in the abdominal aorta according to their specific gravities. This makes it possible to efficiently embolize the side branch R without filling the entire aneurysm with an embolic body of embolic material, thereby preventing or suppressing collapse of the stent graft SG and preventing or suppressing distal embolization.

In addition, the second embolus 12a, which has the larger specific gravity than the first embolus 11a and the second embolus 12a, is configured to contain a radiopaque material. Therefore, the embolus containing the radiopaque material can be visually recognized in a radiographic image during the procedure.

In addition, the specific gravity of the first plug 11a can be made smaller than that of the second plug 12a by providing an air layer or foam inside.

Third Embodiment
Figure 16 is a diagram showing an embolic material 10b according to the third embodiment placed in a side branch R (IMA) of an aneurysm, and Figure 17 is a diagram showing a state in which an embolic material 10b is placed in a side branch R (LA) of an aneurysm different from that in Figure 16.

In the first embodiment, the embolic material 10 is described as being made of only one type of substantially spherical embolic body 11, but this is not limited thereto. As shown in FIG. 16, the embolic material 10b can be configured to include a mass in which at least a part of the substantially spherical third embolic body 11b (diameter dg3) and a substantially spherical fourth embolic body 12b (diameter dg4<diameter dg3, see FIG. 16) different in size from the third embolic body 11b are integrally formed. For example, the third embolic body 11b can be configured to have a larger volume than the fourth embolic body 12b. The embolic material 10b can be compressed and inserted into the sheath lumen 42 of the delivery catheter 40 by configuring it to be compressible and deformable in the same manner as in the first embodiment. The diameter of the IMA is diameter dr1, as in the second embodiment, and the diameter of the LA is diameter dr2.

Here, the third embolus 11b and the fourth embolus 12b can be configured to have different specific gravities in the same manner as in the second embodiment in order to control which one is to be fitted into the entrance of the aneurysm. The fourth embolus 12b can have a higher specific gravity than the third embolus 11b by including a metal marker or metal particles, or a radiopaque material such as barium sulfate. This allows the embolus containing metal particles or barium sulfate to be visually recognized by contrast images.

In addition, the third plug 11b can be made to have a lighter specific gravity than the fourth plug 12b by providing an air layer (cavity) inside or by forming it into a sponge structure (foam) such as a closed cell structure or an open cell structure.

In this embodiment, the embolic material 10b travels with the blood flow to reach the entrance of the side branch R within the aneurysm. During the procedure on the abdominal aortic aneurysm, the patient is lying on his/her back, with the LA positioned on the posterior side and the IMA positioned on the ventral side. As a result, as shown in FIG. 16, the third embolic body 11b, which has a relatively small specific gravity, can be adhered to the entrance of the side branch R at the ventral portion such as the IMA within the aneurysm. Also, as shown in FIG. 17, the fourth embolic body 12b, which has a large specific gravity, can be adhered to the entrance of the side branch R at the posterior portion such as the LA. By configuring the embolic material 10b in this way, the orientation of the third embolic body 11b and the fourth embolic body 12b can be controlled. This makes it possible to efficiently embolize the side branch R and prevent or suppress the collapse of the stent graft SG within the aneurysm, while more effectively preventing or suppressing distal embolization.

By linking roughly spherical bodies of different dimensions, such as the third embolic body 11b and the fourth embolic body 12b, the embolic material 10b can closely contact embolic bodies of similar size, such as the third embolic body 11b or the fourth embolic body 12b, even if the IMA and LA are different in size. Note that the configuration and treatment method of the embolic material delivery medical system other than the embolic material in this embodiment are the same as those in the first embodiment, so will not be described here.

As described above, in this embodiment, the embolus is configured to include a mass formed integrally with the third embolus 11b and the fourth embolus 12b, which has dimensions different from those of the third embolus 11b. By configuring it in this way, it is possible to place emboluses of similar sizes according to the different sizes of side branches R, such as the IMA and LA, to easily block the entrance of the side branch R and prevent or suppress distal embolization.

The fourth embolus 12b is also configured to contain a radiopaque material. Therefore, the embolus containing the radiopaque material can be visually identified in a radiographic image during the procedure.

In addition, the specific gravity of the third plug 11b can be made smaller than that of the fourth plug 12b by providing an air layer or foam inside.

(Variation 1 of the third embodiment)
Fig. 18 is a diagram showing an embolic material 10c according to the first modified example of the third embodiment placed in a side branch R of an aneurysm. In the third embodiment, the embolic material 10b includes the third embolic body 11b and the fourth embolic body 12b, but the embolic material 10c may be configured as follows. That is, the embolic material 10c includes a third embolic body 11c, a fourth embolic body 12c, and a fifth embolic body 13c as shown in Fig. 18.

In this modified example, the volume of the third embolus 11c is larger than the volume of the fourth embolus 12c and the fifth embolus 13c, and the volume of the fourth embolus 12c and the fifth embolus 13c is approximately the same. In other words, if the diameter of the third embolus 11c is diameter dg3 and the diameter of the fourth embolus 12c is diameter dg4, the diameter of the fifth embolus 13c is equal to diameter dg4. The volumetric sizes of the third embolus, the fourth embolus, and the fifth embolus are not limited to the above, and the third embolus, the fourth embolus, and the fifth embolus may be configured to have different volumes.

In addition, the specific gravity of the embolus to be placed on the dorsal side (fifth embolus 13c in FIG. 18) is configured to be greater than that of the embolus to be placed on the ventral side (fourth embolus 12c in FIG. 18). The method for adjusting the specific gravity between the third embolus 11c, fourth embolus 12c, and fifth embolus 13c can be the same as that for the third embolus 11b and fourth embolus 12b in the third embodiment.

This configuration also makes it possible to efficiently embolize the side branch R, prevent or suppress the stent graft SG placed in the abdominal aortic aneurysm from being crushed by the embolic material, and prevent or suppress distal embolization.

Fourth Embodiment
Fig. 19 is a schematic diagram showing an embolic material 10d according to the fourth embodiment, and Fig. 20 is a diagram showing the state in which the embolic material 10d shown in Fig. 19 is loaded into an embolic material loading catheter 20. Fig. 21 is a diagram showing the state in which the embolic material 10d shown in Fig. 19 is placed at the entrance of a side branch R of an abdominal aortic aneurysm, and Fig. 22 is a diagram showing that the embolic material 10d shown in Fig. 19 is prevented from migrating distally from the entrance of the side branch R.

In the first to third embodiments, one or more types of embolic bodies are discharged into the abdominal aortic aneurysm in a mutually independent state. However, the multiple embolic bodies 11d constituting the embolic material 10d can be connected together in a ring shape by a connecting member 14 (corresponding to a connecting portion) as shown in FIG. 19. The connecting member 14 connects each of the multiple embolic bodies 11d to one or two embolic bodies 11d at intervals. In other words, the connecting member 14 connects the multiple embolic bodies 11d at intervals along a single line. In this embodiment, the connecting member 14 connects each of the multiple embolic bodies 11d to two adjacent embolic bodies 11d at intervals. The connecting member 14 can be configured to connect adjacent embolic bodies 11d among the multiple embolic bodies 11d so that they can be spaced apart from each other by a distance greater than the diameter dg of the embolic body 11d, and to be ring-shaped and endless. The material of the connecting member 14 is not particularly limited as long as it is flexible and can connect multiple emboluses 11d at intervals, and the same material as the emboluses 11d can be used. The shape of the connecting member 14 is also not particularly limited as long as it can connect the emboluses to form a ring shape, and thread-like members, coil-like members, etc. can be used as examples. Examples of thread-like members include threads made of biocompatible resins such as polyethylene terephthalate, polyethylene, nylon, regenerated cellulose, ethylene-vinyl alcohol copolymer, polymethyl methacrylate, polyacrylonitrile, and polystyrene. Examples of coil-like members include coils made of biocompatible metal materials such as nickel-titanium alloys.

The embolic material 10d is configured to be capable of embolizing the side branch R connected to the aneurysm space or to be retained in the aneurysm space, and can be compressed and inserted into the sheath lumen 42 of the delivery catheter 40 by being configured to be compressible and deformable as in the first embodiment. The embolic bodies 11d connected by the connecting member 14 are substantially spherical like the embolic body 11 in the first embodiment, and can be configured to be prepared in multiple numbers. Since the multiple embolic bodies 11d are configured from the same embolic body, the diameter dg of each embolic body 11d is configured to be substantially uniform even when dimensional errors are taken into consideration. Each of the multiple embolic bodies 11d is configured to be compressible and deformable so that it can be fitted alone into the side branch R with a diameter dr of 2 to 5 mm smaller than the diameter dg of each of the multiple embolic bodies 11d. In other words, each of the multiple embolic bodies 11d is configured to be compressible and deformable so as to be in close contact with the side branch R over the entire circumferential direction. The number of embolization bodies 11d that make up the embolization material 10d is not particularly limited, but for example, it can be configured to have 3 to 10 bodies (7 bodies in FIG. 19).

The embolic material 10d can be formed into a ring shape by using the connecting member 14, but the connecting member 14 is flexible and made supple. Therefore, among the embolic bodies 11d connected by the connecting member 14, the embolic bodies 11d facing each other can be arranged adjacent to each other inside the loading lumen 22 as shown in FIG. 20, and the connecting member 14 can be folded to compactly accommodate the embolic material 10d in the loading lumen 22.

The procedure using the embolic material 10d is almost the same as in the first embodiment, with the difference being that the size of the embolic material determined in accordance with the measurement results of the vascular diameter of the side branch R is the entire embolic material 10d, rather than the embolic body 11d of the embolic material 10d alone; otherwise, it is the same as in the first embodiment. Therefore, a detailed description will be omitted.

In the procedure using the embolic material 10d according to this embodiment, when the embolic material 10d is discharged from the tip of the delivery catheter 40, the embolic material 10d can move by the blood flow within the aneurysm to the vicinity of the entrance of the side branch R. Here, even if one embolic body 11f of the embolic material 10d enters the inside of the side branch R as shown in Figures 21 and 22, the embolic material 10d is connected by the connecting member 14. Therefore, even if one embolic body 11f of the embolic body 11d enters the side branch R as shown in Figures 21 and 22, the embolic body 11f cannot enter the distal part of the side branch R because the embolic body 11h and the embolic body 11g adjacent to the embolic body 11f integrated by the connecting member 14 collide with each other. Or, even if the embolus 11f enters the side branch R, either the embolus 11h or the embolus 11g adjacent to the embolus 11f will get stuck in the side branch entrance, preventing the embolus 11f from entering the distal part of the side branch R. In this way, even if the embolus can enter the side branch R on its own, by integrating it with the connecting member 14, it is possible to prevent or suppress it from being drawn into the distal side of the side branch R.

As described above, in this embodiment, the embolic material 10d is configured to be capable of embolizing or placing a blood vessel connected to the aneurysm space, and includes an embolization body 11d and a connecting member 14. The embolization body 11d is formed into an approximately spherical shape, and multiple embolization bodies 11d are prepared. The connecting member 14 is configured to connect each of the multiple embolization bodies 11d to one or two embolization bodies 11d at intervals, and is configured to be flexible. Each of the multiple embolization bodies 11d is configured to be compressively deformable so as to fit into a blood vessel having a diameter dr smaller than the diameter dg of each of the multiple embolization bodies 11d. By configuring in this way, the embolization body 11d can be prevented from moving to the distal side of the side branch R by connecting the embolization bodies to each other using the connecting member 14. In addition, the smaller the dimensions of the delivery catheter 40 used during the procedure, the less operational troubles there are. Therefore, by reducing the dimensions of the embolization body 11d of the embolic material 10d, a relatively small delivery catheter 40 can be used, which can contribute to reducing the risk of blood vessel perforation during delivery. In addition, the plug bodies 11d are connected by the connecting member 14, so that the plug bodies 11d can be arranged approximately evenly.

The connecting member 14 is configured to connect multiple emboli 11d in a ring shape. This makes it easier for multiple emboli 11d to be grouped together, making it difficult for the emboli 11d to enter the side branch R one by one from the inlet of the side branch R, and prevents the emboli 11d connected by the connecting member 14 from moving distally from the inlet of the side branch R, thereby preventing or suppressing distal embolism.

In addition, the connecting member 14 connects adjacent occlusion bodies 11d among the multiple occlusion bodies 11d so that they can be spaced apart by more than the diameter dg of the occlusion body 11d. This improves the embolization rate of the side branch.

In addition, by configuring the embolic material 10d to include 3 to 10 embolic bodies 11d, the embolic bodies 11d connected by the connecting member 14 can act together to prevent the embolic material 10d from moving distally from the entrance of the side branch R. This makes it possible to prevent or suppress distal embolization.

The diameter dg of each of the multiple embolic bodies 11d is configured to be approximately uniform. Therefore, even if any of the multiple embolic bodies 11d is close to the entrance of the side branch R, the embolic material 10d can be prevented from moving distally from the entrance of the side branch R, thereby preventing or suppressing distal embolization.

In addition, each of the multiple embolic bodies 11d that make up the embolic material 10d is configured to be compressible and deformable so that it can fit independently into a side branch R with a diameter of 2 to 5 mm that branches off from the blood vessel in which the stent graft SG for the abdominal aortic aneurysm is placed. This configuration prevents the embolic material 10d from migrating distally from the entrance of the side branch R in the abdominal aortic aneurysm, thereby preventing or suppressing distal embolism.

In addition, each of the multiple embolic bodies 11d is configured to be compressible and deformable so as to be in close contact with the entire circumferential direction of the side branch R. This configuration allows a relatively large contact area between the embolic body 11d and the side branch R, preventing the embolic material 10d from migrating distally from the entrance of the side branch R, and preventing or suppressing distal embolization.

(Modification 1 of the fourth embodiment)
Fig. 23 is a diagram showing an embolic material 10e constituting an embolic material delivery medical system according to a first modified example of the fourth embodiment, and Fig. 24 is a diagram showing a state in which the embolic material 10e shown in Fig. 23 is housed in the loading lumen 22 of the embolic material loading catheter 20. Fig. 25 is a diagram showing a state in which the embolic material 10e shown in Fig. 23 is placed at the entrance of a side branch R.

In the fourth embodiment, the embolic bodies 11d constituting the embolic material 10d are connected in a ring shape by the connecting member 14, but the embolic material 10e may be connected as follows. Note that in the first modified example, the configuration other than the embolic material constituting the embolic material delivery medical system and the embolic body 11d constituting the embolic material 10e are the same as in the fourth embodiment, so the description will be omitted.

The connecting member 14e constituting the embolic material 10e linearly connects the embolic bodies 11d as shown in FIG. 23 in the first modified example. That is, the connecting member 14e connects each of the embolic bodies 11d other than the embolic bodies located at both ends in the longitudinal direction of the embolic bodies to the two adjacent embolic bodies 11d at intervals. The connecting member 14e also connects the embolic bodies 11d located at both ends in the longitudinal direction of the embolic bodies to one adjacent embolic body 11d at intervals. The connecting member 14e can adopt the same material as the connecting member 14 as long as it can linearly connect the embolic bodies 11d, and is flexible and supple. Therefore, as shown in FIG. 24, the embolic material 10e can be compactly accommodated in the loading lumen 22 of the embolic material loading catheter 20, which has a small internal space.

The procedure using the embolic material 10e differs from the fourth embodiment only in that the connecting member 14e is different from the connecting member 14, and therefore detailed description will be omitted. As an explanation of the concept of preventing or suppressing distal embolization with the embolic material 10e according to the first modified example, it is assumed that the embolic body 11d closest to the entrance of the side branch enters the entrance of the side branch R. In such a case, even if the connecting member 14e linearly connects the embolic bodies 11d, it is considered that the second and subsequent embolic bodies 11d viewed from the side closer to the entrance of the side branch R do not advance endlessly to the distal side of the side branch. As the embolic bodies 11d advance one by one to the distal side of the side branch R, the contact area between the inner wall of the side branch R and the embolic body 11d increases, which becomes a frictional force and prevents further advancement of the embolic body 11d to the distal side. The concept of preventing or suppressing distal embolization of the embolic body can be applied not only to the first modified example but also to the embolic material 10d of the fourth embodiment.

As described above, in the first modified example, the embolic material 10e linearly connects the embolic bodies 11d with the connecting member 14e. Even with this configuration, even if the embolic bodies 11d can enter the side branch R on their own, by integrating them with the connecting member 14e, it is possible to prevent the embolic bodies 11d from being drawn into the distal side of the side branch R, thereby preventing or suppressing distal embolism. Furthermore, among the multiple embolic bodies 11d connected in a line, the dimensions (diameter) of the embolic body 11d at the end in particular may be made larger than the other embolic bodies 11d. This makes it possible to more effectively prevent or suppress distal embolism.

(Example)
Next, experiment 1 regarding the embolization rate using the embolic material 10 according to the present embodiment, experiment 2 regarding distal embolization, and experiment 3 regarding distal embolization using the embolic material 10e were carried out, which will be described below. Fig. 26 is a schematic diagram showing an apparatus used in an experiment evaluating the embolization rate using the embolic material according to one embodiment, and Fig. 27 is a schematic diagram showing an apparatus used in an experiment evaluating the distal embolization using the embolic material according to one embodiment.

(Experiment 1)
In the experiment on the embolization rate, the embolic materials according to the embodiment and the comparative example were filled into the space between the stent graft SG and the abdominal aortic aneurysm through an insertion tube in a system simulating an abdominal aortic aneurysm and a side branch provided in the abdominal aortic aneurysm, and the size of the embolic material capable of embolizing the side branch was confirmed. The abdominal aortic aneurysm and the side branch were made of members made of silicone material. The size of the abdominal aortic aneurysm was 48 mm in width, and the size of the side branch was one with a diameter of 4.5 mm at the portion corresponding to the IMA, and four with a diameter of 4.0 mm at the portion corresponding to the LA. One IMA was provided at a portion simulating the ventral side of the abdominal aortic aneurysm, and four LAs were provided on the opposite side to the IMA, simulating the dorsal side of the abdominal aortic aneurysm. The members simulating the IMA and LA were returned to a reservoir p1 capable of containing liquid, and a centrifugal pump p2 was connected to the reservoir p1 to allow the liquid equivalent to blood to flow. A pressure gauge p3 was connected to a portion corresponding to a blood vessel connected to the abdominal aortic aneurysm to measure the pressure inside the aneurysm. A flow meter p4 was attached to the sites corresponding to the IMA and LA to measure the flow rate of the fluid supplied to the side branches (see FIG. 26). The pressure in the aneurysm was set to 50 mmHg, and the flow rate was set to 20 mL/min in each side branch.

The embolization material 10 used includes the spherical embolization bodies described in the first embodiment, and contains 10 wt% gelatin. The examples and comparative examples are differentiated by particle size. The particle sizes of the examples are 5 mm, 6 mm, and 7 mm, while the particle size of the comparative example is 9 mm.

To embolize the side branches, the embolic materials according to the above-mentioned Examples and Comparative Examples were divided into cases according to particle size, and the abdominal aortic aneurysm was filled with the embolic materials while increasing the filling rate for each particle size. It was confirmed whether the flow rate of the side branches became 0 mL/min, i.e., whether the side branches could be embolized. The embolic material was placed in the aneurysm by pushing the embolic material into the aneurysm space via the delivery catheter using an injection device, with the pressure inside the aneurysm set to 50 mmHg and the flow rate to each side branch set to 20 mL/min.

As a result, with the embolic material according to the embodiment, the flow rate was 0 mL/min in at least four of the five tubes corresponding to the side branches, including the one corresponding to the IMA. On the other hand, with the embolic material according to the comparative example, even when the filling rate of the abdominal aortic aneurysm was increased, the flow rate did not reach 0 mL/min in three of the four tubes corresponding to the LA, which is a side branch. In other words, while the embolic material according to the embodiment was able to embolize almost all of the tubes corresponding to the side branches, the embolic material according to the comparative example was unable to embolize the tubes corresponding to the LA, particularly those with a diameter of 4 mm.

(Experiment 2)
In the experiment on distal embolization, in a system simulating an abdominal aortic aneurysm and a side branch provided in the abdominal aortic aneurysm, the aneurysmal space between the stent graft SG and the abdominal aortic aneurysm was filled with 20 to 30% of the embolic material, and the particle size of the embolic material was changed to confirm whether distal embolization would occur. As shown in FIG. 27, the device used was the device shown in FIG. 26 except that the tube P5 corresponding to the delivery catheter 40 was removed. The embolic material 10 used included the spherical embolic material described in the first embodiment, and flexible acrylic compound spheres were used. The particle sizes of the embolic material confirmed were 4.5 mm, 5 mm, 6 mm, and 7 mm. As the experimental method, the embolic material and fluid were supplied to a site corresponding to an abdominal aortic aneurysm, and it was confirmed whether distal embolization would occur at the site corresponding to the side branch R when the intra-aneurysmal pressure was increased to 50 mmHg, which is the average intra-aneurysmal pressure in clinical practice, and to 125 mmHg, which is the intra-aneurysmal pressure under severe clinical conditions. The evaluation method was that distal embolism occurred when the ball flowed into the side branch 2 cm or more from the entrance of the side branch. In addition, the embolization rate was calculated as the percentage of tubes corresponding to the LA with a flow rate of 0 mL/min when the intraaneurysmal pressure was increased to 50 mmHg.

As a result, it was confirmed that distal embolism occurred when the particle size was 5 mm or less, but that distal embolism did not occur when the particle size was 6 mm or 7 mm. It was confirmed that the embolization rate under the conditions of Experiment 2 was roughly equivalent to or higher than that of embolic materials with particle sizes of 6 mm and 7 mm for embolic materials with particle sizes of 4, 5 mm, and 5 mm. Thus, according to Experiments 1 and 2, it was confirmed that the appropriate particle size for embolic material 10, which is a spherical embolic body alone, for a blood vessel with a diameter of 4 mm is roughly 6 to 7 mm.

(Experiment 3)
Next, using a system similar to that of Experiment 2 (see FIG. 27), it was confirmed whether distal embolization occurs in an embolic material 10e in which five spherical embolic bodies 11d described in Modification 1 of the fourth embodiment are connected. The embolic material 10e used includes the linearly connected embolic bodies 11d described in Modification 1 of the fourth embodiment, and flexible acrylic compound spheres are used as the embolic bodies, and filamentous polyethylene terephthalate is used as the connecting part connecting the embolic bodies. An embolic material in which five embolic bodies with a particle size of 4.5 mm are arranged linearly with a gap therebetween was used as Example 1, and an embolic material in which five embolic bodies with a particle size of 5 mm are arranged linearly with a gap therebetween was used as Example 2. In addition, an embolic material in which five embolic bodies with a particle size of 4.5 mm are closely attached and arranged linearly was used as a comparative example. The experiment and the judgment of distal embolization were performed in the same manner as in Experiment 2.

As a result, it was confirmed that in the embolic material in which multiple embolic bodies are arranged in a line with a gap between them, no distal embolism occurs, regardless of whether the particle size of the embolic bodies is 4.5 mm (Example 1) or 5 mm (Example 2). It was also confirmed that the embolization rates of Examples 1 and 2 are comparable to the embolization rate of an embolic material with a particle size of 7 mm in Experiment 2 under the same conditions. In other words, it was found that in the embolic material in which multiple embolic bodies are arranged in a line with a gap between them, the embolic bodies with particle sizes of 4.5 mm and 5 mm are capable of sufficiently embolizing a 4 mm LA. On the other hand, in the embolic material in which five embolic bodies are closely attached and arranged in a line as a comparative example, distal embolization does not occur, but the embolization rate is significantly reduced, and it was confirmed that it is almost impossible to embolize side branches.

From the results of Experiments 2 and 3, it was confirmed that even if a spherical embolus alone has a particle size that would cause distal embolization, by connecting multiple embolus in a linear fashion with spaces between them, it is possible to embolize the side branch while preventing distal embolization. Specifically, for a blood vessel with a diameter of 4 mm, it was confirmed that an embolus material in which multiple spherical embolus are connected in a linear fashion with spaces between them can embolize the blood vessel while preventing distal embolization, even if the embolus particle size is 4.5 to 5 mm. In addition, since it was possible to embolize the side branch even when multiple embolus are arranged in a linear fashion with spaces between them, it is suggested that an embolus material in which multiple emboluses with particle sizes of 6 mm and 7 mm, which were confirmed to embolize the side branch in Experiment 1, are arranged in a linear fashion with spaces between them, and can embolize the blood vessel while preventing distal embolization.

In Experiments 1 to 3, the experiments were performed on a blood vessel with a diameter of 4 mm. Here, if the diameter of the blood vessel is reduced by, for example, 1 mm, the appropriate size for the particle size of the spherical embolus is also reduced by 1 mm, and if the diameter of the blood vessel is increased by, for example, 1 mm, the appropriate size for the particle size of the spherical embolus is also increased by 1 mm. Therefore, for a blood vessel with a diameter of 2 mm, the appropriate size for the particle size of the embolus material that is a single spherical embolus is calculated to be approximately 4 to 5 mm, and if it includes linearly connected emboluses, it is calculated to be 2.5 to 3 mm. For a blood vessel with a diameter of 5 mm, the appropriate size for the particle size of the embolus material that is a single spherical embolus is calculated to be approximately 7 to 8 mm, and if it includes linearly connected emboluses, it is calculated to be 5.5 to 6 mm.

The present invention is not limited to the above-mentioned embodiment, and various modifications are possible within the scope of the claims. Figure 8 is a schematic cross-sectional view showing a delivery catheter 40a according to a modified example of Figure 6, and Figure 9 shows the state in which an embolic material loading catheter 20 is connected to the delivery catheter 40a according to Figure 8.

In the first embodiment, it was explained that the dimensions of the inner wall forming the lumen of the sheath lumen 42 of the delivery catheter 40 can be smaller than the loading lumen 22 of the embolic material loading catheter 20. In this regard, the base end side inner wall of the sheath 41 forming the sheath lumen 42a of the delivery catheter may be configured to have a tapered portion 42b as shown in FIG. 8 to reduce the difference in inner diameter between the loading lumen 22 and the sheath lumen 42a. By configuring it in this way, the embolic material 10 can flow more smoothly from the loading lumen 22 to the sheath lumen 42a as shown in FIG. 9.

In addition, in the third embodiment, the specific gravities of the third embolus 11b and the fourth embolus 12b are different, but the specific gravities of the third embolus 11b and the fourth embolus 12b may be the same.

10, 10a, 10b, 10c, 10d, 10e Embolic material,
11, 11d embolus,
11a first plug;
12a second plug;
11b, 11c third plug;
12b, 12c fourth embolus;
13c fifth plug;
14, 14e connecting member (connecting portion),
dg, dg1, dg2, dg3, dg4 diameter (diameter of embolus),
dr, dr1, dr2 diameter (diameter of side branch vessel),
R: lateral branch (lateral branch vessel);
SG stent graft.

Claims (20)

An embolization material capable of embolizing a blood vessel connected to a luminal space or capable of being placed in the luminal space,
A plurality of embolus bodies formed in a substantially spherical shape;
and a flexible connecting portion connecting each of the plurality of occlusion bodies to one or two of the occlusion bodies at intervals;
Each of the plurality of embolic bodies is an embolic material that is compressible and deformable so as to fit into a blood vessel having a diameter smaller than that of each of the plurality of embolic bodies. The embolization material according to claim 1, wherein the connecting portion connects a plurality of the embolization bodies in a ring shape. The embolization material according to claim 2, wherein the connecting portion connects adjacent embolization bodies of the plurality of embolization bodies so that the adjacent embolization bodies can be spaced apart from each other by a distance greater than the diameter of the embolization body. The embolic material according to claim 1, wherein the plurality of embolic bodies consists of 3 to 10 embolic bodies. The embolic material according to claim 1, wherein the diameter of each of the plurality of embolic bodies is substantially uniform. The embolic material according to claim 1, wherein each of the multiple embolic bodies is compressible and deformable so as to fit independently into a side branch blood vessel having a diameter of 2 to 5 mm that branches off from a blood vessel in which a stent graft for abdominal aortic aneurysm is placed. The embolic material according to claim 6, wherein each of the plurality of embolic bodies is compressible and deformable so as to be in close contact with the side branch blood vessel over the entire circumferential direction. The abdominal aortic aneurysm is then placed in a catheter-like vessel, and the catheter is then placed into a catheter-like vessel.
The embolic body is an embolic material that can be compressed and deformed so that the embolic body can fit alone into a side branch blood vessel having a diameter of 2 to 5 mm that branches off from the blood vessel in which the stent graft of the abdominal aortic aneurysm is placed. The abdominal aortic aneurysm is then placed in a catheter-like vessel, and the catheter is then placed into a catheter-like vessel.
The embolic body has a diameter of 4 to 7 mm when filled into the aneurysm space, and is configured to be compressed and deformed to fit into a side branch blood vessel branching off from the blood vessel in which the stent graft of the abdominal aortic aneurysm is placed. The embolic material according to claim 8 or 9, wherein the embolic body is compressible and deformable so as to be in close contact with the side branch blood vessel over the entire circumferential direction. The embolic material according to claim 8 or 9, wherein the embolic body is compressible and deformable so as to partially fit into the entrance of the side branch blood vessel. The embolic material according to claim 8 or 9, which contains multiple embolic bodies of only one type. The embolus includes a plurality of the embolus,
The embolic material according to claim 8 or 9, comprising a first embolic body and a second embolic body having a specific gravity greater than that of the first embolic body. The embolic material according to claim 8 or 9, wherein the embolic body includes a mass in which a third embolic body and a fourth embolic body having dimensions different from those of the third embolic body are integrally formed. The embolic material according to claim 13, wherein the second embolic body includes a radiopaque material. The embolic material according to claim 14, wherein the fourth embolic body includes a radiopaque material. The embolic material according to claim 13, wherein the first embolic body contains an air layer inside. The embolic material according to claim 14, wherein the third embolic body contains an air layer inside. The embolic material according to claim 13, wherein the first embolic body includes a foam. The embolic material according to claim 14, wherein the third embolic body includes a foam.