JP7532001B2 - Treatment Equipment - Google Patents

Description

The present invention relates to a treatment device used in treating, for example, arterial dissection (dissecting aneurysm).

In recent years, when stenosis or blockage occurs in blood vessels or other tubular organs in the body, or when a dissecting aneurysm occurs in a blood vessel, a technique called stent placement has been used in which a stent made of wire (plain wire) is placed at the affected area to expand and maintain the lumen of the tubular organ or prevent the rupture of an aneurysm. In particular, when treating arterial dissection in a blood vessel, for example, a stent graft with a tubular graft that covers the stent is used.

Recently, the Open Stent Graft (OSG) method has been proposed as one of the treatment methods for aortic dissection in the thoracic aorta. In this OSG method, the aorta is incised after the chest is opened, a stent graft is inserted through the incision, and the base end of the stent graft is sutured to the patient's blood vessel to form an anastomosis, and if necessary, an artificial blood vessel separate from the stent graft is anastomosed to the anastomosis.

In addition, in such procedures using the OSG method, a delivery catheter such as that disclosed in Patent Document 1 is used. When the stent graft is inserted through the incision, the stent graft in a contracted state is mounted (held) on this catheter.

Patent No. 6718455

However, in general, there is a demand for improved convenience during treatment with such treatment devices, such as delivery catheters. Therefore, proposals that make it possible to improve the convenience during such treatment are desirable.

It is desirable to provide a treatment device that can improve convenience during treatment.

A treatment device according to an embodiment of the present invention includes a catheter having a shaft extending along an axial direction, a stent graft including a stent and an additional structure, and having a first region in which only the stent is arranged along the axial direction, and a second region in which at least the additional structure is arranged, a cover for holding the stent in a reduced diameter state in the distal region of the shaft, with the first region located on the distal side of the shaft and the second region located on the proximal side of the shaft, and a pull tube extending from near the distal end of the catheter to the proximal side along the axial direction. The cover has a cylindrical outer layer portion located on the outer periphery of the shaft, an inner layer portion located on the inner periphery of the shaft and extending through the shaft to the proximal side of the catheter, and a folded portion connecting the outer layer portion and the inner layer portion at the distal side of the shaft. The stent is held in a reduced diameter state between the outer layer portion and the shaft. In addition, a pusher is provided at the distal end of the pull tube, which abuts against the stent at the distal end side of the stent in the reduced diameter state.

In the treatment device according to one embodiment of the present invention, the outer layer portion, the inner layer portion, and the folded portion are each provided on the cover, and the stent in the first region of the stent graft is held in a reduced diameter state between the outer layer portion and the shaft. As a result, when the stent in the reduced diameter state is deployed from within the cover and expanded in diameter by an operation (pulling operation) of pulling the base end side of the inner layer portion of the cover toward the base end of the catheter, the following occurs. That is, the outer layer portion of the cover is pulled into the inside of the shaft via the folded portion and gradually pulled toward the base end side of the catheter, and the stent in the reduced diameter state is sequentially deployed from within the cover and expanded in diameter by its self-expansion force. Therefore, for example, unlike the case where a stent graft (stent, etc.) in a reduced diameter state is placed between the inner layer portion of the cover and the shaft, and a pulling operation is performed on the base end side of the outer layer portion of the cover (comparative example), the following occurs. That is, when the stent in the reduced diameter state is deployed from within the cover by pulling, the additional structure located on the base end side (the second region) of the stent is prevented from interfering with the operation on the proximal side (the base end side) . The pull tube is further provided, and the pusher is provided at the tip of the pull tube. As a result, when the stent in the reduced diameter state is deployed from within the cover, the pull tube is pulled in the direction of the base end of the catheter in addition to the pulling operation on the base end side of the inner layer part of the cover described above, so that the following occurs. That is, the stent in the reduced diameter state is deployed and expanded from within the cover while being pushed toward the base end side of the shaft by the pusher, so that the tip (distal end) of the stent gradually moves toward the base end side, and the stent is deployed from the base end side. Therefore, when the stent graft is placed in the patient's body, the occurrence of the jumping phenomenon of the stent (the action of the stent suddenly shortening toward the base end side when deployed) is suppressed, and as a result, the convenience during treatment is further improved.

In addition , a first pulling operation, which is an operation of pulling the base end side of the inner layer of the cover toward the base end of the catheter, may be started, followed by a second pulling operation, which is an operation of pulling the pull tube toward the base end of the catheter, so that the stent in the contracted state is deployed from within the cover and expanded in diameter while being pushed toward the base end side of the shaft by the pusher. In this case, the occurrence of the jumping phenomenon of the stent is suppressed as described above when the stent graft is placed in the patient's body by starting the second pulling operation after the first pulling operation.

Furthermore, in this case, a marker may be provided in the base end region of the inner layer of the cover to indicate the approximate timing for starting the second pulling operation after starting the first pulling operation. In this case, the marker can be used to allow the operator to easily grasp the approximate timing for starting the second pulling operation after starting the first pulling operation. As a result, convenience during treatment is further improved.

In addition, in a treatment device according to one embodiment of the present invention, the additional structure may include, for example, a tubular graft and a cuff portion disposed near the stent-side end of the graft.

According to a treatment device according to one embodiment of the present invention, the outer layer portion, the inner layer portion, and the folded portion are each provided on the cover, and the stent in the first region of the stent graft is held in a contracted state between the outer layer portion and the shaft, so that the following is achieved. That is, when performing a pulling operation to deploy the contracted stent from within the cover, it is possible to avoid the risk that the additional structure portion will get in the way of the operation at the hand side. Therefore, by performing treatment using a treatment device equipped with such a cover, it is possible to improve convenience during treatment.

1 is a schematic diagram illustrating an example of a schematic configuration of a treatment device according to an embodiment of the present invention. 2 is a schematic diagram illustrating a detailed configuration example of the inside of a cover illustrated in FIG. 1 . FIG. 2 is a schematic diagram showing a detailed configuration example of the stent graft shown in FIG. 1 . 2 is a schematic diagram showing an example of a method of using the treatment device shown in FIG. 1. FIG. 5 is a schematic diagram showing an example of a method of use following FIG. 4 . FIG. 6 is a schematic diagram showing an example of a method of use following FIG. 5 . FIG. 13 is a schematic diagram showing an example of a method for placing a stent graft when a treatment device according to a comparative example is used. 1 is a schematic diagram showing an example of a method for placing a stent graft when a treatment device according to an embodiment is used. FIG. 9 is a schematic diagram showing an example of the placement method following FIG. 8 .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The description will be given in the following order.
1. Embodiment (Example of a treatment device provided with a pull tube having a pusher)
2. Modifications

1. Preferred embodiment
[General Configuration]
Fig. 1 is a schematic side view of an example of the schematic configuration of a treatment device (treatment device 5) according to an embodiment of the present invention. The treatment device 5 is a device used in the treatment of arterial dissection using the OSG method, and in this example, as shown in Fig. 1, includes a catheter 1 (delivery catheter), a stent graft 2, a cover 3, and a pull tube 41. The stent graft 2, which will be described in detail later, is placed in a site to be treated (e.g., in a blood vessel such as an artery) using the catheter 1 during the above-mentioned treatment, for example.

(Catheter 1)
The catheter 1 is a medical device used to deliver the stent graft 2 to the above-mentioned treatment target site in a patient. As shown in Fig. 1, the catheter 1 includes a delivery shaft 11 and a handle 12 (holding portion, grip). The delivery shaft 11 corresponds to one specific example of the "shaft" of the present invention.

The delivery shaft 11 is made of a flexible tubular structure (tubular member) and has a shape that extends (stretches) along the Z-axis direction, which is its axial direction (longitudinal direction). In the distal end region of the delivery shaft 11 along the axial direction, as shown in FIG. 1, a portion of the stent 21 (the stent 21 in the first region A1 described later) of the stent graft 2 described later is held in a contracted state inside the cover 3 described later during the above-mentioned treatment. The proximal end region of the delivery shaft 11 corresponds to the portion housed in the handle 12. The intermediate region between the distal end region and the proximal end region is the region located between the cover 3 and the handle 12 as shown in FIG. 1.

The length (total length) of such a delivery shaft 11 along the axial direction is, for example, about 300 to 900 mm, preferably about 400 to 800 mm, more preferably about 450 to 600 mm, and a suitable example is 570 mm. The length of the tip region is set appropriately according to the length of the stent graft 2 to be mounted, and is, for example, about 30 to 350 mm, preferably about 50 to 300 mm, and more preferably about 100 to 280 mm. The length of the intermediate region is, for example, about 100 to 250 mm, preferably about 120 to 220 mm, and more preferably about 130 to 200 mm, and a suitable example is 150 mm.

The outer diameter of the tip region is, for example, about 5 to 20 mm, preferably about 8 to 15 mm, and a suitable example is 11 mm. The outer diameter of the intermediate region is, for example, about 5 to 20 mm, preferably about 8 to 15 mm, and a suitable example is 10 mm.

1, the handle 12 is attached to the base end portion (base end region) of the delivery shaft 11 and is the part that the operator (doctor) grasps (holds) when using the catheter 1. The handle 12 is shaped to extend along its axial direction (Z-axis direction).

The length of the handle 12 along the axial direction is, for example, about 50 to 200 mm, preferably about 60 to 180 mm, and more preferably about 80 to 170 mm, with a suitable example being 145 mm. The outer diameter of the handle 12 is, for example, about 3 to 50 mm, preferably about 5 to 25 mm, and a suitable example being 20 mm. Such a handle 12 is made of a synthetic resin, for example, polycarbonate, acrylonitrile-butadiene-styrene copolymer (ABS), or the like.

Here, Figure 2 (Figures 2(A) and 2(B)) are schematic side views showing an example of the detailed internal configuration of the cover 3 shown in Figure 1. Note that in Figure 2(B), for convenience, the stent 21 inside the cover 3 has been omitted. Also, Figure 3 is a schematic showing an example of the detailed configuration of the stent graft 2 shown in Figure 1. Specifically, Figure 3(A) shows a schematic view of an example of the external configuration of the stent graft 2, and Figure 3(B) shows a schematic view of an example of the configuration when the inside of the cuff portion 23 in the stent graft 2 is seen through.

(Stent graft 2)
As shown in Figures 1 and 3, the stent graft 2 has a tubular (cylindrical) structure extending along its axial direction (Z-axis direction), and is configured to include a stent 21, a graft 22, and a cuff portion 23 (see Figure 3). The stent graft 2 (stent 21) has a self-expanding structure that can be held in a contracted state. The length of the stent graft 2 when expanded along the axial direction is, for example, about 270 to 370 mm. The outer diameter of the stent 21 when expanded is, for example, about 30 mm, and the inner diameter of the stent 21 when expanded is, for example, about 28 mm.

As shown in Figs. 1 and 3, the stent 21 is constructed using one or more wires W (strands), and in this example has a tubular (cylindrical) structure. Specifically, for example, this tubular structure is constructed of a mesh structure, and such a tubular mesh structure is formed by weaving the wires W in a predetermined pattern. Examples of the weaving pattern include plain weave, twill weave, and stockinette weave. Alternatively, the tubular mesh structure may be formed by arranging one or more wires W that have been zigzag folded and processed into a cylindrical shape.

As the material for the wire W, a metal wire is preferred, and a shape memory alloy that is particularly given a shape memory effect and superelasticity by heat treatment is preferably used. However, depending on the application, stainless steel, tantalum (Ta), titanium (Ti), platinum (Pt), gold (Au), tungsten (W), etc. may be used as the material for the wire W. As the shape memory alloy, for example, nickel (Ni)-Ti alloy, copper (Cu)-zinc (Zn)-X (X = aluminum (Al), iron (Fe), etc.) alloy, Ni-Ti-X (X = Fe, Cu, vanadium (V), cobalt (Co), etc.) alloy, etc. may be preferably used. As such a wire W, for example, a synthetic resin may be used. In addition, a metal wire having a surface coated with Au, Pt, etc. by plating or other means, or a composite wire having a core material made of a radiopaque material such as Au or Pt covered with an alloy may be used as the wire W.

As shown in Figs. 1 and 3, the graft 22 has a tubular (cylindrical) shape and is disposed on the proximal side of the stent 21 and the cuff portion 23 (see Fig. 3). Also, as shown in Fig. 3, the cuff portion 23 is disposed near the end of the graft 22 on the stent 21 side. Specifically, as shown in Fig. 3(B), for example, the cuff portion 23 is disposed so as to cover the outer periphery of the graft 22 near such an end. Also, in the region within the cuff portion 23, the ends of the graft 22 and the stent 21 are sutured to each other (see Fig. 3(B)).

Here, the graft 22 and the cuff 23 each correspond to a specific example of the "additional structure" in the present invention. The graft 22 and the cuff 23 may be fixed to the delivery shaft 11 and the handle 12, respectively. This is because, when configured in this way, the graft 12 and the cuff 23 are prevented from shifting in position due to the retraction of the cover 3.

1 and 3, a first region A1 and a second region A2 are provided along the axial direction (Z-axis direction) of the stent graft 2. The first region A1 is located at the distal end of the stent graft 2, and is an area in which only the stent 21 is arranged. On the other hand, the second region A2 is located at the proximal end (proximal end side of the first region A1) of the stent graft 2, and is an area in which at least the graft 22 and the cuff portion 23 are arranged. In the example of this embodiment, the graft 22 and the cuff portion 23 are arranged in the second region A2, but the stent 21 is not arranged, but this example is not limited to this. That is, in addition to the graft 22 and the cuff portion 23, the stent 21 may also be arranged (on the inner periphery side of the graft 22) in the second region A2.

The length of the first region A1 in the axial direction when expanded is, for example, about 200 mm, and the length of the second region A2 in the axial direction is, for example, about 70 to 170 mm. The length of the graft 22 in the axial direction is, for example, about 50 to 150 mm, and the length of the cuff portion 23 in the axial direction is, for example, about 20 mm.

Examples of such grafts 22 that can be used include thermoplastic resin formed into a cylindrical shape by a molding method such as extrusion molding or blow molding, woven fabrics made of thermoplastic resin fibers or extremely fine metal wires formed into a cylindrical shape, nonwoven fabrics made of thermoplastic resin or extremely fine metal formed into a cylindrical shape, flexible resin sheets or porous sheets formed into a cylindrical shape, and structures in which resin dissolved in a solvent is formed into a thin cylindrical shape by electrospinning.

Here, the above-mentioned knitted or woven fabrics may be any known knitted or woven fabric, such as a plain weave or twill weave. Also, fabrics with pleats, such as crimped fabrics, may be used. Among these, knitted or woven fabrics made of thermoplastic resin fibers formed into a cylindrical shape, and even plain woven fabrics made of thermoplastic resin fibers formed into a cylindrical shape, are particularly preferred because of their excellent strength, porosity, and productivity.

As the thermoplastic resin, for example, polyolefins such as polyethylene, polypropylene, and ethylene-α-olefin copolymers, polyamides, polyurethanes, polyesters such as polyethylene terephthalate, polybutylene terephthalate, polycyclohexane terephthalate, and polyethylene-2,6-naphthalate, and fluororesins such as polyethylene fluoride and polypropylene fluoride, and other resins that are durable and cause little tissue reaction can be used. Of these, polyesters such as polyethylene terephthalate, which are chemically stable, highly durable, and cause little tissue reaction, and fluororesins such as polyethylene fluoride and polypropylene fluoride can be preferably used.

(Cover 3)
As described above, the cover 3 is a member for holding the stent 21 of the stent graft 2 in a reduced diameter state in the distal region of the delivery shaft 11. Specifically, in this example, as shown in Figures 1 to 3, the stent 21 in the first region A1 is held within the cover 3 with the first region A1 located at the distal end side of the delivery shaft 11 and the second region A2 located at the proximal end side of the delivery shaft 11. The outer diameter of the cover 3 is, for example, about 5.0 to 20.0 mm, and preferably about 10 to 15 mm.

In this example, the cover 3 is made of a soft cover. By covering the stent 21 in a contracted state with a soft cover, the stent 21 can be securely held. In addition, because the cover 3 is soft, it can easily follow the shape changes of the tip region of the delivery shaft 11, compared to a hard cylindrical body (sheath) or the like.

1, 2(A) and 2(B), the cover 3 of this embodiment has a cylindrical structure extending along the axial direction. The length of the cover 3 along the axial direction (the total length of the outer layer 32, the inner layer 31 and the folded-back portion 33: the total length of the cover 3) is, for example, about 300 to 1300 mm.

As shown in Figs. 1, 2(A) and 2(B), the cover 3 has a two-layer structure (double structure) having an inner layer 31 and an outer layer 32. That is, the cover 3 has a cylindrical outer layer 32 and an inner layer 31 located on the inner periphery of the outer layer 32. In the example shown in Fig. 2(A), the outer layer 32 is located on the outer periphery of the delivery shaft 11, and the inner layer 31 is located on the inner periphery of the delivery shaft 11. The cover 3 also has a folded portion 33 that connects (connects) the outer layer 32 and the inner layer 31 at the tip of the delivery shaft 11 (see Figs. 1 and 2(A)). Specifically, the cover 3 is formed by folding a cylindrical tube member inward, and the folded portion corresponds to the inner layer 31. 1, 2(A) and 2(B), the base end side of the inner layer portion 31 extends through the delivery shaft 11 to the base end side of the catheter 1. Specifically, as shown in FIG. 1, the base end side of the inner layer portion 31 passes through the insides of the delivery shaft 11 and the handle 12, respectively, and protrudes from the base end side of the handle 12.

2A, the stent 21 in the stent graft 2 is held in the contracted state between the outer layer 32 of the cover 3 and the delivery shaft 11 (see arrow P0). In this embodiment, as shown in Figs. 1 and 2A, a marker 310 is provided in the base end region (internal region of the handle 12) of the inner layer 31 of the cover 3. The marker 310 indicates the timing for starting the pulling operation on the pull tube 41 (described later) after starting the pulling operation on the cover 3 (inner layer 31) (described later), and is provided in a manner that is visible to the operator.

Each of the cover 3 (the outer layer 32, the inner layer 31, and the folded portion 33, etc.) is made of a material that exhibits translucency or transparency (light transmission), for example. Examples of such materials that exhibit translucency or transparency include polyolefins such as polyethylene, polypropylene, and ethylene-α-olefin copolymers, polyamide, polyimide, polyurethane, polyesters such as polyethylene terephthalate, polybutylene terephthalate, polycyclohexane terephthalate, and polyethylene-2,6-naphthalate, fluororesins such as polyethylene fluoride and polypropylene fluoride, and woven or knitted fabrics made of resin fibers such as silicone, or structures such as films and sheets, or combinations thereof. For the purpose of reinforcement, etc., these may contain thin wires or short fibers of metal, etc. Incidentally, the members that make up the cover 3 described above may be manufactured in advance in a cylindrical shape using the above-mentioned materials, or flat materials processed into a cylindrical shape, or combinations thereof.

This configuration of the cover 3 allows the operation of expanding the stent graft 2 to be performed by pulling the cover 3, which will be described later. Details of the operation of expanding the stent graft 2 (the method of placing the stent graft 2 during treatment) will be described later (Figures 8 and 9).

(Pull tube 41)
The above-mentioned pull tube 41 is a tubular member extending from the vicinity of the tip of the catheter 1 to the base end side along the axial direction (Z-axis direction) as shown in Fig. 1, Fig. 2(A), and Fig. 2(B). Specifically, the pull tube 41 is arranged from the vicinity of the tip of the delivery shaft 11 (as shown in Fig. 2(A), between the outer layer 32 and the inner layer 31 of the cover 3, between the layers of the delivery shaft 11 and the stent 21 in a contracted state) through the inside of the handle 12 and the like, and protrudes from the base end side of the handle 12. Also, as shown in Fig. 2(B), the pull tube 41 has a half-split shape in which the base end side portion is split in half along the radial direction (the lower half is cut out). This is to prevent the base end side portion of the pull tube 41 from contacting the handle 12. The length of the pull tube 41 along the axial direction (axial length L41 shown in Fig. 2(B)) is, for example, about 300 to 700 mm. The axial length L40 (see FIG. 2B) of the half portion of the pull tube 41 is, for example, about 370 mm.

1, 2(A) and 2(B), a pusher 42 is provided at the tip of the pull tube 41, which abuts against the stent 21 at the tip side of the stent 21 in the contracted state. Specifically, as shown in Fig. 2(A), the pusher 42 is disposed on the outer periphery of the delivery shaft 11, between the stent 21 in the contracted state and the folded-back portion 33. The axial length L42 (see Fig. 2(B)) of the pusher 42 is, for example, about 10 mm.

[Actions, actions and effects]
(A. Basic Operation)
The treatment device 5 of this embodiment is used, for example, in the treatment of arterial dissection. Specifically, the operator operates the catheter 1 to deliver the stent graft 2 in a contracted state to the site to be treated in the patient (e.g., inside a blood vessel such as an artery), expand it, and then place it there. By placing the stent graft 2 in the site to be treated in this manner, it becomes possible to expand and maintain the blood vessel lumen while suppressing blood flow to a tear in the inner wall of the blood vessel. In particular, the stent graft 2 is used, for example, in the treatment using the OSG method, which is one of the treatment methods for arterial dissection in the thoracic aorta.

Here, with reference to Figures 4 to 6, an overview of a treatment method for arterial dissection, etc., using this OSG method (method of using the treatment device 5) will be described.

Each of Figures 4 to 6 is a schematic diagram showing one example of how to use the treatment device 5 during such treatment. Note that, here, an example will be described in which the blood vessel to be treated, that is, the artery 9 (thoracic aorta), is a portion including the distal aortic arch (the portion of the arch branch 9B shown in Figures 4 to 6) and the proximal descending aorta. Figure 6 also shows an enlarged view of the portion designated by the symbol P7.

First, as shown in Figure 4, in the OSG method, after the patient's chest is opened, the treatment device 5 configured as shown in Figures 1 to 3 is used to insert the stent graft 2 in a reduced diameter state through an opening made by incising a part of the artery 9 (see arrow P8). Specifically, the stent graft 2 is inserted from the tip side (cover 3 side) of the delivery shaft 11 of the catheter 1. At this time, as shown in Figures 1 and 2(A), for example, the stent graft 2 is held inside the cover 3 in a reduced diameter state in the tip region of the delivery shaft 11 of the catheter 1.

Here, if the artery 9 to be treated is in a state of arterial dissection, for example, the artery 9 will contain an arterial lumen (true lumen), which is the original blood flow path, and a new lumen (false lumen) that has been created by a tear in the blood vessel inner wall. In such a case, to avoid the risk of the catheter 1 being erroneously inserted into the false lumen, the catheter 1 is inserted along a specified guidewire. In other words, the catheter 1 is inserted while passing such a guidewire through the pore (lumen) of the catheter 1.

Specifically, a guidewire is first inserted into artery 9 from the base of the patient's leg (groin), and then passed through artery 9 and pulled out from the opening described above. Since the guidewire is inserted into artery 9 from the peripheral side, it is inserted reliably into the true lumen without being mistakenly inserted into the false lumen. The length of such a guidewire is, for example, about 50 to 450 cm, and its outer diameter is, for example, about 0.2 to 1.0 mm.

Next, the catheter 1 is inserted into the artery 9 along the guidewire using the opening as an entrance (see arrow P8 in FIG. 4). As described above, the guidewire is securely inserted into the true lumen, so by inserting the catheter 1 into the artery 9 along the guidewire, the catheter 1 is also securely inserted into the true lumen. In other words, even in the case of arterial dissection, the risk of the catheter 1 being inserted into the false lumen is avoided.

Next, as shown in Figure 4, for example, the treatment device 5 is used to deliver the stent graft 2 to a location in the artery 9 beyond the area to be treated (near the site where the arterial dissection has occurred) (see arrow P8).

Next, the self-expansion force of the stent 21 is used to expand (deploy) the stent graft 2. Specifically, first, the operator of the catheter 1 pulls (pulls toward the base end) the cover 3, which will be described later. Then, as will be described in detail later, the cover 3 is removed from the stent graft 2. As a result, the stent graft 2 gradually expands due to the self-expansion force of the stent 21. After that, the catheter 1, cover 3, and pull tube 41 are each removed from the patient's body.

In this way, the stent graft 2 is fixed to the inner wall of the artery 9, as shown in Figure 5, for example. As a result, the lumen of the artery 9 near the site of arterial dissection is expanded and maintained. After that, the graft 22 is cut to the required length, and the cuff portion 23 is also cut to the required length.

6, felt 80 is wrapped around the outer periphery of the cuff 23 and anastomosed, and the base end of the cuff 23 is anastomosed to the artery 9 (aortic arch) (see symbol P80). Felt 80 is also wrapped around the outer periphery of the base end of the graft 22 and anastomosed to the aortic arch (see symbol P80).

In this way, the inner circumference near the site of arterial dissection is covered by the stent graft 2, allowing blood to flow through the stent graft 2 and blocking the flow of blood into the tear (false lumen) in the inner wall of the blood vessel.

In addition, the OSG method has the following advantages over the conventional treatment method of inserting a catheter through the base of the patient's leg (groin) to carry a stent graft to the treatment target area. That is, the OSG method has the advantage of being able to treat areas with important branches (e.g., the aortic arch), which are extremely difficult to treat with the conventional treatment method. In addition, compared to the method of resecting the diseased area, replacing it with an artificial blood vessel, and anastomosing both ends, the suturing of the descending aorta (distal anastomosis) is substituted by fixation with the stent graft 2. In other words, the OSG method omits anastomosis between the tip side of the stent graft 2 and the descending aorta, simplifying the anastomosis work. Therefore, the operation time (extracorporeal circulation time) can be shortened, and the left thoracotomy or large chest incision required for suturing the descending aorta is avoided, reducing the surgical invasion on the patient (reducing the burden on the patient during treatment). Furthermore, the OSG method has the advantage that the implantation range of the artificial blood vessel can be set to a wide range, and surgical treatment of nearby complications is also possible. In addition, since the stent graft applied to the OSG method is not introduced from the groin area as in the above-mentioned conventional treatment method, it is not necessary to pass it through a thin blood vessel, and the outer diameter can be large (thick) to a certain extent even in the contracted state.

Furthermore, in this embodiment, as shown in Figures 5 and 6, blood also flows through the gaps in the stent 21 to the branching portion (arch branch 9B) from the blood vessel (artery 9, etc.) in which the stent graft 2 is placed. This eliminates the need for reconstruction procedures for this branching portion (such as anastomosis with an artificial blood vessel), making it possible to shorten the surgical time during treatment and reduce invasiveness.

(B. Actions and Effects of Cover 3, etc.)
Next, with reference to FIGS. 7 to 9 in addition to FIGS. 1 to 6, the operation and effects of the cover 3 and the like of this embodiment will be described in detail in comparison with a comparative example.

Figure 7 is a schematic diagram of an example of a method for placing the stent graft 2 when a treatment device (treatment device 105) according to a comparative example is used. Also, Figures 8 and 9 are schematic diagrams of an example of a method for placing the stent graft 2 when a treatment device 5 according to the present embodiment is used. Note that Figures 7 and 8 also show the insertion direction (arrow P8) of the catheter into the artery 9, as described above with reference to Figure 4. Also, in the comparative example shown in Figure 7, for convenience, only the stent 21 of the stent graft 2 is shown, and the graft 22 and the cuff portion 23 are omitted.

(B-1. Placement method of comparative example)
First, in the treatment device 105 of the comparative example shown in Fig. 7, the stent graft 2 is placed in the blood vessel (artery 9) to be treated as follows. Note that in the treatment device 105 of the comparative example, instead of the above-mentioned cover 3 and delivery shaft 11 in the treatment device 5 of the embodiment, a cover 103 and a delivery shaft 101 are provided, respectively, and the above-mentioned pull tube 41 is not provided. Also, in the treatment device 105 of the comparative example, unlike the treatment device 5 of the embodiment (see Fig. 2(A)), as shown in Fig. 7(A), the stent graft 2 (stent 21, etc.) in a reduced diameter state is placed between the inner layer 31 of the cover 103 and the delivery shaft 11 (between layers) (see arrow P0).

In this comparative example, first, as shown in FIG. 7(A), the catheter is inserted into the artery 9 (see arrow P8). Then, as shown in FIG. 7(B), the operator of the catheter pulls the base end of the outer layer 32 of the cover 103 toward the base end of the delivery shaft 101 (see arrow P101). By pulling the outer layer 32 of the cover 103 in this way, the inner layer 31 of the cover 103 is gradually pulled out toward the base end of the delivery shaft 11 via the folded-back portion 33 (see arrow P102). Then, as shown in FIG. 7(B), the stent graft 2 in the contracted state is sequentially deployed from within the cover 103 by the self-expansion force of the stent 21 and expands in diameter (see arrow P103). Specifically, the stent graft 2 is gradually deployed and expands in diameter from its tip side toward its base end side. As a result, the entire stent graft 2 is eventually deployed and expands in diameter.

However, in a comparative example that uses a treatment device 105 equipped with such a cover 103, when the stent graft 2 in a contracted state is deployed from within the cover 103 and expanded by the above-mentioned pulling operation, problems such as the following may occur.

That is, first, in this comparative example, as described above, the stent graft 2 (stent 21, etc.) in a reduced diameter state is placed between the inner layer 31 of the cover 103 and the delivery shaft 101, and a pulling operation is performed on the base end side of the outer layer 32 of the cover 103. Therefore, when such a pulling operation is performed on the outer layer 32 of the cover 103, the graft 22 and the cuff portion 23 (additional structure) located on the base end side (second region A2) of the stent 21 may get in the way of the operation on the proximal side (base end side).

In addition, when the stent 21 is deployed, it also stretches along its axis (Z-axis direction), which may cause a jumping phenomenon (rapid shortening towards the base end when deployed) of the stent 21 when the stent graft 2 is placed in the patient's body. If this jumping phenomenon of the stent 21 increases, the placement position of the stent graft 2 may shift or the patient's blood vessel (artery 9, etc.) may be damaged.

For these reasons, this comparative example may be less convenient when treating arterial dissection and the like using the OSG method.

(B-2. Placement method according to the present embodiment)
In contrast, in the treatment device 5 of this embodiment shown in Figures 8 and 9, the above-mentioned cover 3 is utilized to place the stent graft 2 in the blood vessel (artery 9) to be treated as follows.

That is, first, as shown in FIG. 8A, for example, the catheter 1 is inserted into the artery 9 (see arrow P8). Then, the operator of the catheter 1 performs an operation (first pulling operation) to pull the base end side of the inner layer 31 of the cover 3 toward the base end of the catheter 1 (see arrow P11). By performing such a pulling operation on the inner layer 31 of the cover 3, the outer layer 32 of the cover 3 is pulled into the inside of the delivery shaft 11 via the folded portion 33 (see arrow P2), and is gradually pulled toward the base end side of the catheter 1.

Therefore, as shown in Fig. 8B, for example, the stent 21 in a contracted state is gradually deployed from within the cover 3 by the self-expanding force of the stent 21, and expands in diameter (see arrow P3). Specifically, the stent 21 is gradually deployed and expands in diameter from its base end side toward its tip end side.

Next, as shown in Fig. 9(A) and Fig. 9(B), the operator of the catheter 1 performs an operation (second pulling operation) to pull the pull tube 41 toward the base end of the delivery shaft 11 (see arrow P12). That is, in the example shown in Fig. 8 and Fig. 9, the pulling operation (first pulling operation) on the inner layer 31 of the cover 3 is started, and then the pulling operation (second pulling operation) on the pull tube 41 is started. Note that the operator can grasp the timing of the start of the second pulling operation after the start of such a first pulling operation by using the marker 310 provided in the base end region of the inner layer 31 of the cover 3. That is, the second pulling operation is started with the timing when such a marker 310 is displaced from the inside to the outside of the handle 12 as a guide, as shown in Fig. 9(A) and Fig. 9(B), in conjunction with the first pulling operation.

In this way, in addition to the pulling operation on the inner layer 31 of the cover 3, the pulling operation on the pull tube 41 is also performed, resulting in the following: That is, for example, as shown in Figures 9(A) to 9(C), the stent 21 in a contracted state is pushed toward the base end of the delivery shaft 11 by the pusher 42 (see arrow P4), and is deployed from within the cover 3 and expands in diameter (see arrow P3). As a result, the stent 21 gradually moves toward the base end, and is gradually deployed and expands in diameter from its tip side toward the base end.

As a result, as shown in Fig. 9C, the entire stent 21 is finally deployed and expanded in diameter. Note that the timing of starting the second pulling operation (pulling operation on the pull tube 41) after the start of the first pulling operation is desirably set within the following range, for example. That is, when the length of the first region A1 is LA1 and the axial length of the portion of the stent 21 exposed to the outside by the first pulling operation (the exposed portion length of the stent 21) is LB1, it is desirably to start the second pulling operation within a range that satisfies the following formula (1).
0.3≦(LB1/LA1)≦0.7 ...(1)

(B-3. Actions and Effects)
In this manner, in the treatment device 5 of this embodiment, the outer layer portion 32, the inner layer portion 31, and the folded-back portion 33 are each provided on the cover 3, and the stent 21 in the first region A1 of the stent graft 2 is held in a reduced-diameter state between the outer layer portion 32 and the delivery shaft 11. As a result, in this embodiment, when the base end side of the inner layer portion 31 of the cover 3 is pulled toward the base end of the catheter 1, the stent 21 in a reduced-diameter state is deployed from within the cover 3 and expanded in diameter, as follows.

That is, the outer layer 32 of the cover 3 is pulled into the inside of the delivery shaft 11 through the folded portion 33 and gradually pulled toward the base end side of the catheter 1, so that the stent 21 in the reduced diameter state is successively deployed from within the cover 3 by its self-expansion force and expands in diameter. Therefore, unlike the case where the stent graft 2 (stent 21, etc.) in the reduced diameter state is placed between the inner layer 31 of the cover 103 and the delivery shaft 101 and the base end side of the outer layer 32 of the cover 103 is pulled, as in the above comparative example, the following occurs. That is, when the stent 21 in the reduced diameter state is deployed from within the cover 3 by the pulling operation, the graft 22 and the cuff portion 23 (additional structure) located on the base end side (second area A2) of the stent 21 are prevented from interfering with the operation on the hand side (base end side). Therefore, in this embodiment, by performing treatment using a treatment device 5 equipped with such a cover 3, it is possible to improve the convenience of the above-mentioned treatment.

In this embodiment, a pull tube 41 is provided that extends from near the tip of the catheter 1 to the base end along the axial direction (Z-axis direction), and a pusher 42 is provided at the tip of the pull tube 41, which abuts against the stent 21 at the tip side of the contracted stent 21. Therefore, when the contracted stent 21 is deployed from within the cover 3, the pull tube 41 is pulled toward the base end of the catheter 1 in addition to the pulling operation against the base end side of the inner layer portion 31 of the cover 3 described above, as follows. That is, the contracted stent 21 is deployed and expanded from within the cover 3 in a state where it is pushed toward the base end side of the delivery shaft 11 by the pusher 42, so that the tip (distal end) of the stent 21 gradually moves toward the base end side while the stent 21 is deployed from the base end side. Therefore, when the stent graft 2 is placed inside the patient's body, the occurrence of the jumping phenomenon of the stent 21 described above is suppressed (see, for example, the ``X'' mark indicated by the dashed arrow m in Figure 9 (C)), making it possible to further improve convenience during treatment.

Furthermore, in this embodiment, after the operation of pulling the base end side of the inner layer 31 of the cover 3 toward the base end of the catheter 1 (first pulling operation) is started, the pull tube 41 is pulled toward the base end of the catheter 1 (second pulling operation), so that the stent 21 in a contracted state is deployed from within the cover 3 and expanded in diameter while being pushed toward the base end of the delivery shaft 11 by the pusher 42. In this way, the above-mentioned first pulling operation is started followed by the above-mentioned second pulling operation, so that when the stent graft 2 is placed in the patient's body, it is possible to suppress the occurrence of the jumping phenomenon of the stent 21 as described above.

In addition, in this embodiment, the marker 310 described above is provided in the base end region of the inner layer 31 of the cover 3, so that the following occurs. That is, by using such a marker 310, the operator can easily grasp the approximate timing for starting the second pulling operation described above after starting the first pulling operation described above. As a result, it is possible to further improve convenience during treatment.

2. Modified Examples
Although the present invention has been described above by way of the embodiment, the present invention is not limited to this embodiment and various modifications are possible.

For example, the configuration (shape, position, size, number, material, etc.) of each component described in the above embodiment is not limited, and other shapes, positions, sizes, numbers, materials, etc. may be used. Specifically, in the above embodiment, specific configuration examples of the cover 3 are given and described, but, for example, the configuration (shape, position, size, number, material, etc.) of this cover 3 may be other shapes, positions, sizes, numbers, materials, etc. In detail, for example, the above-mentioned marker 310 may not be provided on the inner layer 31 of this cover 3.

In the above embodiment, the graft 22 and the cuff 23 are included as examples of the "additional structure" in the stent graft of the present invention, but the present invention is not limited to this example. That is, for example, at least one of the graft 22 and the cuff 23 may not be provided in the stent graft 2, or another member may be included as the "additional structure" described above. Also, for example, the graft 22 may further include a supply blood vessel having a branched structure.

Furthermore, in the above embodiment, the case where the inner layer 31 and the outer layer 32 of the cover 3 are integrated with each other via the folded-back portion 33 has been described, but this is not the only possible case. That is, for example, the inner layer and the outer layer of the cover may be separate from each other, and the inner layer and the outer layer may be connected (joined) by a separate folded-back portion (joining portion).

In the above embodiment, a specific configuration example of the pull tube 41 has been described, but the present invention is not limited to this configuration example. Specifically, for example, the pusher 42 described above may not be provided at the tip of the pull tube 41. In some cases, for example, the pull tube 41 itself may not be provided within the treatment device 5.

In addition, in the above embodiment, an example has been described in which the stent graft is provided with one first region disposed on the distal end side within the cover and one second region disposed on the proximal end side within the cover, but this is not limited to the example. That is, for example, another second region may be further provided on the distal end side of the first region in the stent graft. In other words, the stent graft may be provided with the first region sandwiched between two second regions.

In the above embodiment, a specific example of a method for placing a stent graft using a treatment device has been described, but the method for placing the stent graft is not limited to the example described in the above embodiment. Specifically, for example, the above embodiment describes an example in which a pulling operation (first pulling operation) on the base end side of the inner layer 31 of the cover 3 is started, and then a pulling operation (second pulling operation) on the pull tube 41 is started, but the method is not limited to this example. That is, for example, the first and second pulling operations may be performed simultaneously in parallel, or, conversely, the first pulling operation may be started after the second pulling operation is started in some cases.

In addition, in the above embodiment, the treatment device is configured with a catheter, a stent graft, and a cover, but this is not limiting. That is, for example, the treatment device may be configured with only a catheter, a catheter and a stent graft, or a catheter and a cover.

In addition, in the above embodiment, the treatment device (catheter, stent graft, cover, etc.) applied to the treatment of the thoracic aorta including the distal aortic arch and the proximal descending aorta has been described as an example, but is not limited to this example. In other words, the treatment device of the present invention can also be applied to the treatment of blood vessels such as other arteries (e.g., the ascending aorta, thoracic and abdominal aorta, abdominal aorta, iliac artery, femoral artery, etc.).

Claims (4)

a catheter having an axially extending shaft;
A stent graft comprising a stent and an additional structure, the stent graft having, along the axial direction, a first region in which only the stent is disposed, and a second region in which at least the additional structure is disposed;
a cover for holding the stent in a reduced diameter state in a distal end region of the shaft, with the first region positioned on the distal end side of the shaft and the second region positioned on the proximal end side of the shaft ;
a pull tube extending from near the tip of the catheter to the base end along the axial direction;
Equipped with
The cover is
a cylindrical outer layer portion located on an outer circumferential side of the shaft;
an inner layer portion located on the inner circumferential side of the shaft and extending through the shaft to the base end side of the catheter;
a folded portion connecting the outer layer portion and the inner layer portion at a tip side of the shaft,
The stent is held in the reduced diameter state between the outer layer portion and the shaft ,
A pusher is provided at the tip of the pull tube, which comes into contact with the stent on the tip side of the stent in the reduced diameter state.
Treatment device. After a first pulling operation is started, which is an operation of pulling a base end side of the inner layer portion of the cover toward the base end direction of the catheter,
A second pulling operation is performed to pull the pull tube toward the base end of the catheter,
The treatment device according to claim 1 , wherein the stent in the reduced diameter state is deployed from within the cover and expanded in diameter when pushed toward the base end side of the shaft by the pusher. In the base end region of the inner layer portion of the cover,
The treatment device according to claim 2 , further comprising a marker that indicates an indication of a timing for starting the second pulling operation after starting the first pulling operation. The additional structure is
A cylindrical graft;
A cuff portion disposed near the end of the graft on the stent side;
The treatment device according to any one of claims 1 to 3 , comprising:

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