medical devices

Abstract

To provide a medical device capable of improving convenience.SOLUTION: The medical device according to one embodiment of the present invention comprises: a stent graft; a shaft extending along an axial direction and inserted in the stent graft; a buffer member disposed on a tip side of the shaft; a cover for covering at least a part of the stent graft; and a pull-in mechanism for pulling in the cover into the shaft from between the tip of the shaft and a rear end of the buffer member.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to medical devices. [Background technology]

[0002] A stent graft delivery system (medical device) is disclosed in Patent Document 1, for example. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6718455 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for improved convenience in use of medical devices, and it is desirable to provide a medical device that can improve convenience. [Means for solving the problem]

[0005] According to one embodiment of the present disclosure 1st The medical device includes a stent graft, a shaft extending in the axial direction and inserted into the stent graft, a buffer member disposed on the distal end side of the shaft, a cover covering at least a portion of the stent graft, and a retraction mechanism for retracting the cover into the shaft from between the distal end of the shaft and the rear end of the buffer member. The device includes a handle disposed on the proximal end side of the shaft, a first rod-shaped member connected to the buffer member and extending through the shaft into the handle, and a base end member connected near the proximal end of the first rod-shaped member and configured to be movable in the proximal direction within the handle when the cover is retracted by the retraction mechanism. The retraction mechanism has a second rod-shaped member connected to the proximal end side of the cover located within the shaft and engaging with the base end member when the cover is retracted to a predetermined position. A second medical device according to an embodiment of the present disclosure includes a stent graft, a shaft extending axially and inserted into the stent graft, a buffer member disposed on the distal end of the shaft, a cover covering at least a portion of the stent graft, a retraction mechanism configured to retract the cover into the shaft from between the distal end of the shaft and the proximal end of the buffer member, a handle disposed on the proximal end of the shaft, a first rod-shaped member connected to the buffer member and extending through the shaft into the handle, and a proximal member connected near the proximal end of the first rod-shaped member and configured to be movable in the proximal direction within the handle when the retraction mechanism retracts the cover. The handle has a stop portion that stops the proximal movement of the proximal member. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a schematic diagram illustrating an example of a schematic configuration of a medical device according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic diagram illustrating an example of a cross-sectional configuration of the medical device illustrated in FIG. [Figure 3] 3 is an exploded view schematically illustrating an example of a cross-sectional configuration of some members of the medical device shown in FIG. 2. FIG. [Figure 4] 4 is a schematic diagram illustrating an example of a cross-sectional configuration taken along line IV-IV shown in FIG. 2. FIG. [Figure 5] 3 is a schematic diagram illustrating an example of a cross-sectional configuration taken along line VV shown in FIG. 2. FIG. [Figure 6] 6 is a schematic diagram illustrating an example of a cross-sectional configuration taken along line VI-VI shown in FIG. 2. FIG. [Figure 7] 2 is a schematic diagram illustrating an example of the detailed configuration and operation of a handle and the like illustrated in FIG. 1. FIG. [Figure 8] FIG. 2 is a schematic diagram illustrating an example of a method of using the medical device shown in FIG. [Figure 9] FIG. 9 is a schematic diagram illustrating an example of a method of use following FIG. 8. [Figure 10] FIG. 10 is a schematic diagram illustrating an example of a method of use following FIG. 9. [Figure 11] 2 is a schematic diagram showing a detailed example of how to use the medical device shown in FIG. 1. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The description will be made in the following order. 1. Embodiment (Example of a medical device equipped with a retraction mechanism for a cover for a stent graft) 2. Variations

[0008] <1. Embodiment> [Schematic configuration] FIG. 1 is a side view (YZ side view) that schematically shows an example of the general configuration of a medical device (medical device 5) according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view (YZ cross section) of the medical device 5. 2 is a schematic diagram showing an example of a configuration of a shaft 11 (an example of a configuration of a shaft 11). An enlarged view of the area designated by the symbol P4 (near the tip of the shaft 11, which will be described later) is also shown on the right side of FIG. 2. For convenience, the illustration of the stent graft 2, which will be described later, is omitted from FIG. 2. In each drawing, the axial direction of the shaft 11 is defined as the Z-axis direction. The plane perpendicular to the axial direction of the shaft 11 is defined as the XY plane, and the X-axis direction and the Y-axis direction are defined within the XY plane.

[0009] The medical device 5 is a device used in treating arterial dissection or the like using, for example, the OSG (Open Stent Graft) method. The medical device 5 mainly includes a catheter 1 (delivery catheter), a stent graft 2, a cover 3, a buffer member 40, rod-shaped members 41 and 42, and a base member 43. The stent graft 2, which will be described in detail later, is placed in the region to be treated (for example, in a blood vessel such as an artery) using the catheter 1 during the above-mentioned treatment.

[0010] FIG. 3 is an exploded view schematically illustrating an example of a cross-sectional configuration (example of a Y-Z cross-sectional configuration) of some components of the medical device 5 illustrated in FIG. 2. Specifically, FIG. 3(A) mainly illustrates an example of a cross-sectional configuration of the shaft 11, the cover 3, and the rod-shaped member 42, while FIG. 3(B) mainly illustrates an example of a cross-sectional configuration of the shaft 11, the buffer member 40, and the rod-shaped member 41. FIG. 4 is a schematic diagram illustrating an example of a cross-sectional configuration (example of an X-Y cross-sectional configuration) taken along line IV-IV in FIG. 2. FIG. 5 is a schematic diagram illustrating an example of a cross-sectional configuration (example of an X-Y cross-sectional configuration) taken along line VV in FIG. 2. FIG. 6 is a schematic diagram illustrating an example of a cross-sectional configuration (example of an X-Y cross-sectional configuration) taken along line VI-VI in FIG. 2. As with FIG. 2, the stent graft 2 is not illustrated in FIGS. 4 to 6 for convenience.

[0011] (Catheter 1) The catheter 1 is a medical device used to deliver the stent graft 2 to a site in a patient that is to be treated. The catheter 1 includes a shaft 11 and a handle 12.

[0012] The shaft 11 is made of a flexible tubular structure (tubular member) and extends along the Z-axis direction. The distal portion of the shaft 11 is inserted into the stent graft 2, and the vicinity of the proximal end of the shaft 11 is disposed within the handle 12. In addition, the distal end of the stent graft 2 (the portion of the stent 21 described later) is held in a contracted diameter within the cover 3 in the distal region of the shaft 11 along the Z-axis direction (in this example, the region located distal to the cuff portion 23 described later).

[0013] A portion of the shaft 11, including the tip, is subjected to low-friction processing to reduce friction (to exhibit slipperiness) compared to other portions of the shaft 11. Low-friction processing refers to processing that reduces the coefficient of dynamic friction on the surface, and is performed, for example, by known surface processing or coating processing. Specifically, in the example shown in FIGS. 4 to 6, a portion of the shaft 11 (the portion closer to the tip than the inside of the handle 12) is composed of a metal tubular member 110 (e.g., a stainless steel pipe) and a coating layer 111 that covers the outer surface of the tubular member 110. The coating layer 111 is a layer (overcoat layer) whose coefficient of dynamic friction is lower than that of metal, and is composed of, for example, a fluororesin such as PTFE (polytetrafluoroethylene). For example, the covering layer 111 may be provided on the entire area along the Z-axis direction of the shaft 11. The covering layer 11 may also cover the inner surface of the tubular member 110.

[0014] The handle 12 is attached to the base end of the shaft 11 and is the part that is grasped (held) by the operator (doctor) when using the catheter 1. The handle 12 has a shape that extends along the Z-axis direction. As shown in FIG. 1, the handle 12 contains the vicinity of the base end of the shaft 11, the vicinity of the base end of the rod-shaped members 41 and 42, a base member 43, and the like. An example of a detailed configuration of the handle 12 will be described later (FIG. 7).

[0015] (Stent graft 2) The stent graft 2 has a tubular (cylindrical) structure extending along the Z-axis direction, and is configured to include a stent 21, a graft 22, and a cuff portion 23. The stent 21 has a self-expanding structure that can be maintained in a contracted state.

[0016] At least a portion of the stent 21 is covered with a cover 3. The stent 21 is formed by weaving one or more wires W (element wires) into a tubular mesh structure (see FIGS. 1 and 2). Examples of the weaving pattern include plain weave, twill weave, and stockinette knit. Alternatively, the wires W may be bent in a zigzag pattern and processed into a cylindrical shape to form a tubular mesh structure.

[0017] The material for the wire W is preferably a metal wire, and particularly preferably a shape memory alloy that can be given a shape memory effect and superelasticity by heat treatment. However, depending on the application, stainless steel, tantalum (Ta), titanium (Ti), platinum (Pt), gold (Au), tungsten (W), etc. may also be used as the material for the wire W. Examples of the shape memory alloy that are preferably used include nickel (Ni)-Ti alloys, copper (Cu)-zinc (Zn)-X (X = aluminum (Al), iron (Fe), etc.) alloys, and Ni-Ti-X (X = Fe, Cu, vanadium (V), cobalt (Co), etc.) alloys.

[0018] The graft 22 has a cylindrical shape and is disposed on the proximal side of the stent 21 and the cuff 23. The graft 22 is provided with a branch structure 220 as a blood vessel supply. The cuff 23 is disposed near the distal end of the graft 22 so as to cover the outer periphery of the graft 22. In the region covered by the cuff 23, the ends of the graft 22 and the stent 21 are sutured together.

[0019] Here, the portion including the graft 22 and the cuff 23 corresponds to a specific example of an "additional structure" in the present disclosure. The graft 22 and the cuff 23 may be fixed to, for example, the shaft 11 and the handle 12, respectively. This is because misalignment of the graft 22 and the cuff 23 is prevented when the cover 3, which will be described later, is retracted.

[0020] Examples of the graft 22 that can be used include a structure formed by molding a thermoplastic resin into a cylindrical shape using a molding method such as extrusion molding or blow molding, a knitted or woven fabric made of thermoplastic resin fibers or ultrafine metal wires formed into a cylindrical shape, and a nonwoven fabric made of thermoplastic resin or ultrafine metal formed into a cylindrical shape. Note that the knitted or woven fabrics that can be used include known knitted or woven fabrics such as plain weave or twill weave.

[0021] (Cover 3) The cover 3 has a tubular structure extending along the Z-axis direction, and in this example is made of a soft cover. By covering the stent 21 in a contracted state with the soft cover, the stent 21 can be held in place. Furthermore, because the cover 3 is soft, it can more easily follow the shape changes of the distal end region of the shaft 11 compared to a hard tubular body (sheath) or the like.

[0022] In the initial state (a state in which the stent 21 is held inside the cover 31), the cover 3 has a shape in which a part of a cylindrical tubular member is folded inward. In other words, the cover 31 has an inner portion 31, an outer portion 32, and a folded portion 33 in the initial state.

[0023] The outer portion 32 is a portion of the cover 3 that is positioned outside the shaft 11. The side portion 31 is a portion of the cover 3 that is located inside the shaft 11 (a portion folded back inward) (see Figures 2, 3(A), 5, and 6). The folded back portion 33 is a portion of the cover 3 that is located on the tip side of the shaft 11 and connects the outer portion 32 and the inner portion 31 (see Figures 1, 2, and 3(A)).

[0024] Between the outer portion 32 of the cover 3 and the shaft 11, the stent 21 of the stent graft 2 is held in a reduced diameter state (see arrow P0 in FIG. 2). As shown in FIG. 5, for example, a portion of the inner portion 31 along the Z-axis direction is split in half (with the lower half cut out). This is to allow the base end portion of the rod-shaped member 41 to pass from the inside to the outside of the inner portion 31, as shown in FIGS. 3(A), 3(B), and 4 to 6. The base end of the inner portion 31 extends to the base end within the shaft 11, as shown in FIGS. 2, 3(A), and 6.

[0025] The cover 3 (outer portion 32, inner portion 31, and folded portion 33) is made of, for example, a semi-transparent or transparent (light-transmitting) material. For the purpose of reinforcing the cover 3, thin wires or short fibers of metal or the like may be included.

[0026] Here, when the cover 3 is retracted (the operation of retracting the cover 3 toward the base end inside the shaft 11), the portion that was the outer portion 32 passes through the folded-back portion 33 and gradually changes into the inner portion 31, as will be described in detail later ( FIG. 11 ). Then, when the retraction of the cover 3 is finally completed, both the outer portion 32 and the folded-back portion 33 disappear, and the entire cover 3 becomes the inner portion 31. Note that retraction of the cover 3 means retraction of the cover 3 into the shaft 11 from between the tip of the shaft 11 and the rear end of the buffer member 40.

[0027] Such retraction of the cover 3 expands the stent 21. Details of the operation of expanding the stent 21 (the method of placing the stent graft 2) will be described later (FIGS. 8 to 11).

[0028] [Detailed configuration example of Handle 12] Next, a detailed configuration example of the handle 12 will be described with reference to Fig. 7 in addition to Fig. 1 to Fig. 6. Fig. 7 (Fig. 7(A) to Fig. 7(D)) is a schematic diagram showing a detailed configuration example and an operation example of the handle 12 etc. shown in Fig. 1.

[0029] The rod-shaped member 41 extends from the tip side of the shaft 11 through the inside of the shaft 11 into the handle 12. A buffer member 40 is connected to the tip of the rod-shaped member 41, and a base end member 43 is connected to the base end of the rod-shaped member 41.

[0030] The buffer member 40 is disposed on the distal side of the shaft 11 and the folded portion 33 (in the cover 3) (see FIG. 2), and at least its distal end is hemispherical (see FIGS. 1, 2, and 3(B)). However, the buffer member 40 may have any shape as long as it can provide buffering. For example, the buffer member 40 may have a shape that does not have sharp corners at least in its distal end (in addition to the hemispherical shape described above, for example, a full sphere or a cylindrical shape with curved or rounded corners). The buffer member 40 is a member for protecting the surrounding blood vessels and the like when the shaft 11 and the like are removed from the patient's body. When the stent 21 is held within the cover 3, a predetermined gap G is provided between the distal end of the shaft 11 (and the folded portion 33) and the rear end of the buffer member 40 (see FIG. 2).

[0031] The rod-shaped member 41 has a through-hole H1 formed therethrough along the Z-axis direction, and the buffer member 40 also has a through-hole H2 formed therethrough along the Z-axis direction, and the through-holes H1 and H2 communicate with each other (see FIG. 2). This is a lumen (guidewire lumen) into which a guidewire is inserted. Note that this guidewire is configured to pass through the through-holes H2 and H1, for example, through the base end member 43, and reach the outside of the handle 12 on the proximal side.

[0032] The base end member 43 is configured to be movable in the base end direction within the handle 12 when the cover 3 is retracted (see arrow P43 in FIG. 7(D)).

[0033] A stop portion 121 is provided on the proximal end side within the handle 12. The stop portion 121 is a portion that functions as a stopper that stops the movement of the proximal member 43 in the proximal direction (see arrow P43 in FIG. 7(D)). Specifically, in the example of FIG. 7(D), when the proximal member 43 moves in the proximal direction, the proximal member 43 abuts against (the surface of) the stop portion 121 within the handle 12, thereby stopping the movement of the proximal member 43. However, the configuration of the stop portion 121 is not limited to the examples shown in FIGS. 7(A) to 7(D), and other configurations may be used as long as they are configured to stop the movement of the proximal member 43 in the proximal direction.

[0034] The rod-shaped member 42 extends from inside the shaft 11 into the handle 12 and is made of, for example, a metal material (stainless steel, etc.). The tip of the rod-shaped member 41 is connected to the base end side of the inner part 31 inside the shaft 11. The grip 120 is connected to the base end side of the rod-shaped member 41 via the base end member 43 described above. The grip 120 is disposed on the base end side (hand side) of the handle 12. In addition, an engagement portion 420 is provided on the rod-shaped member 42 near the base end inside the shaft 11 (see FIG. 7(A)).

[0035] The engaging portion 420 is a portion that engages with the proximal end member 43 when the cover 3 is retracted to a predetermined position (see FIGS. 7(C) and 7(D)). Specifically, when the operator of the medical device 5 performs an operation to move the grip 120 toward the proximal end (toward the hand) (see arrow P1 in FIGS. 7(B) to 7(D)), the rod-shaped member 42 and the engaging portion 420 also move toward the proximal end (see arrow P42 in FIGS. 7(B) to 7(D)). Then, as shown in FIG. 7(C), when the engaging portion 420 moves to the distal end position of the proximal end member 43, the rod-shaped member 42 (engaging portion 420) and the proximal end member 43 engage with each other, and the proximal end member 43 moves toward the proximal end together with the engaging portion 420 (see arrow P43 in FIG. 7(D)). As will be described in detail later, the cover 3 is retracted using the grip 120, the rod-shaped member 42, and the like.

[0036] Here, the rod-shaped member 41 corresponds to a specific example of a "first rod-shaped member" in the present disclosure, and the rod-shaped member 42 corresponds to a specific example of a "second rod-shaped member" in the present disclosure. The through holes H1 and H2 correspond to specific examples of a "first through hole" and a "second through hole" in the present disclosure, respectively. Furthermore, the rod-shaped member 42, the engaging portion 420, and the grip 120 correspond to a specific example of a "retraction mechanism" (a mechanism that retracts the cover 3) in the present disclosure. However, for example, the grip 120 may be configured so as not to be included in the "retraction mechanism."

[0037] [Operation, Actions and Effects] (A.Basic movement) The medical device 5 is used, for example, in the treatment of arterial dissection. Specifically, an operator operates the medical device 5 to deliver the stent graft 2 in a contracted state to the site to be treated in the patient (for example, inside a blood vessel such as an artery), expand it, and then place it in place. By placing the stent graft 2 in the site to be treated, it becomes possible to expand and maintain the blood vessel lumen while suppressing blood flow to tears in the inner wall of the blood vessel. Furthermore, the stent graft 2 is used, for example, in treatment using the OSG method, which is one of the treatment methods for arterial dissection in the thoracic aorta.

[0038] Here, an overview of a method for treating arterial dissection and the like using the OSG method (a method for using the medical device 5) will be described with reference to Figures 8 to 10. For the sake of convenience, the branching structure 220 of the stent graft 2 is omitted from Figures 8 to 10 (and Figure 11, which will be described later).

[0039] 8 to 10 are schematic diagrams each showing an example of a method of using the medical device 5 during the above-mentioned treatment. Here, an example will be described in which the artery 9 (thoracic aorta), which is the blood vessel to be treated, is a portion including the distal aortic arch (the portion of the arch bifurcation 9B shown in FIGS. 8 to 10) and the proximal descending aorta. FIG. 10 also shows an enlarged view of the portion designated by the symbol P7.

[0040] First, as shown in Fig. 8, in the OSG method, after a patient's chest is opened, a medical device 5 is used to insert a stent graft 2 in a reduced diameter state through an opening formed by cutting a part of an artery 9 (see arrow P8). Specifically, the stent graft 2 is inserted from the distal end side (cover 3 side) of the shaft 11 of the medical device 5. At this time, the stent 21 is held inside the cover 3 in a reduced diameter state in the distal end region of the shaft 11.

[0041] Here, if the artery 9 to be treated is in a state of arterial dissection, for example, there is an arterial lumen (true lumen) which is the original blood flow path, and a new lumen (false lumen) which is created when the inner wall of the blood vessel is torn, inside the artery 9. In this case, to avoid the risk of the medical device 5 being erroneously inserted into the false lumen, it is inserted into the through-holes H1 and H2 (guidewire lumen) along the guidewire.

[0042] Specifically, first, a guide wire is inserted into artery 9 from the base of the patient's leg (groin), passed through artery 9, and then pulled out from the opening to the outside. Here, since this guide wire is inserted into artery 9 from the peripheral side, the guide wire is inserted into the true lumen without being mistakenly inserted into the false lumen.

[0043] Next, the medical device 5 is inserted into the artery 9 along the guidewire using the opening as an entrance (see arrow P8 in FIG. 8). Because the guidewire has been inserted into the true lumen, inserting the medical device 5 into the artery 9 along the guidewire also results in the medical device 5 being inserted into the true lumen. In other words, even in the case of arterial dissection, the risk of the medical device 5 being inserted into the false lumen is avoided.

[0044] Next, as shown in FIG. 8, for example, the medical device 5 is used to extend the stent graft 2 to a location beyond the site to be treated in the artery 9 (near the site where arterial dissection has occurred) (see arrow P8).

[0045] Next, the self-expansion force of the stent 21 is utilized to expand (deploy) the stent 21. Specifically, first, the operator of the medical device 5 retracts the cover 3. Then, as will be described in detail later, the cover 3 is removed from the stent graft 2. As a result, the stent 21 gradually expands due to the self-expansion force of the stent 21. Thereafter, the components of the medical device 5 (catheter 1, cover 3, buffer member 40, rod-shaped members 41 and 42, base member 43, grip 120, etc.) excluding the stent graft 2 are each removed from the patient's body.

[0046] In this way, the stent graft 2 is fixed to the inner wall of the artery 9, as shown in Figure 9, for example. As a result, the lumen of the artery 9 near the site of arterial dissection is expanded and maintained. Thereafter, the graft 22 is cut to the required length, and the cuff portion 23 is also cut to the required length.

[0047] 10, felt 80 is wrapped around the outer periphery of the cuff 23 for anastomosis, 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 for anastomosis, and this anastomotic portion is anastomosed to the aortic arch (see symbol P80).

[0048] In this way, the inner circumference near the site of arterial dissection is covered by the stent graft 2, allowing blood flow through the stent graft 2 and blocking blood flow into the tear (false lumen) in the inner wall of the blood vessel.

[0049] 9 and 10, 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), thereby shortening the surgical time during treatment and reducing the invasiveness.

[0050] (B. Details of stent graft placement method) Next, the method for placing the stent graft 2 (method for using the medical device 5) in this embodiment will be described in detail with reference to Fig. 11 in addition to Fig. 1 to Fig. 10. Fig. 11 (Fig. 11(A) to Fig. 11(C)) is a schematic diagram showing a detailed example of the method for using the medical device 5. Note that in Fig. 11(C), the cover 3 is not shown for the sake of convenience.

[0051] First, as shown in Figure 11(A), for example, the stent graft 2 is inserted into the artery 9 from the distal end side (cover 3 side) of the shaft 11 of the medical device 5 (see arrow P8). Then, as shown in Figures 11(B) and 11(C), for example, the operator of the medical device 5 retracts the cover 3.

[0052] Specifically, the operator of the medical device 5 moves the grip 120 toward the proximal end (see arrow P1 in FIGS. 7(B) to 7(D), 11(B), and 11(C)). Then, the rod-shaped member 42 and the engaging portion 420 also move toward the proximal end (see arrow P42 in FIGS. 7(B) to 7(D)). By using the grip 120, the rod-shaped member 42, etc. to retract the cover 3 (the inner portion 31) in this manner, the outer portion 32 of the cover 3 is retracted into the shaft 11 via the folded portion 33 (see arrow P2 in FIG. 11(B)). Specifically, as the cover 3 is retracted from between the tip of the shaft 11 and the rear end of the buffer member 40 into the shaft 11, the outer portion 32 of the cover 3 is gradually pulled toward the proximal end of the catheter 1. That is, the portion that was the outer portion 32 gradually changes into the inner portion 31 via the folded portion 33.

[0053] Then, the stent 21 in the reduced diameter state is successively deployed from within the cover 3 by the self-expansion force of the stent 21, and the diameter increases (see arrow P3 in FIG. 11(B)). Specifically, the stent 21 is gradually deployed and increases in diameter from its base end side toward its tip end side.

[0054] 11(C), the entire stent 21 is finally deployed and expanded in diameter. At this time, the rod-shaped member 42 (engaging portion 420) and the proximal member 43 engage with each other within the handle 12 (see FIG. 7(C)), and the proximal member 43 moves together with the engaging portion 420 in the proximal direction (see arrow P43 in FIGS. 7(D) and 11(C)).

[0055] As a result, when the stent 21 is held in the cover 3, a gap G is provided between the tip of the shaft 11 and the rear end of the buffer member 40 (see Fig. 2 and Fig. 11(A)), whereas when the entire stent 21 is deployed and its diameter is expanded, the following occurs: When the rod-shaped member 42 (engagement portion 420) engages with the base end member 43 and the base end member 43 moves toward the base end, the buffer member 40 also moves toward the base end (see arrow P40 in Figure 11 (C)), and as a result, the gap G between the tip of the shaft 11 and the rear end of the buffer member 40 disappears.

[0056] (C. Actions and Effects) The medical device 5 of this embodiment is provided with a buffer member 40 disposed on the distal end side of the shaft 11 and a cover 3 that covers at least a portion of the stent graft 2, and as described above, the cover 3 is retracted into the shaft 11 from between the distal end of the shaft 11 and the proximal end of the buffer member 40. In other words, in this medical device 5, the buffer member 40 is not covered by the cover 3.

[0057] As a result, in this embodiment, when the cover 3 is retracted, unlike, for example, when the cushioning member 40 is also covered by the cover 3 (comparative example), the cover 3 (near the folded portion 33) is prevented from rubbing against the blood vessels in the patient's body. As a result, the operation of retracting the cover 3 becomes easier, and it is possible to improve the convenience of using the medical device 5.

[0058] Furthermore, in this embodiment, when the stent 21 is held within the cover 3, a predetermined gap G is provided between the tip of the shaft 11 and the rear end of the buffer member 40, which results in the following: This gap G functions as a buffer, making it easier to absorb the impact when the buffer member 40 abuts against a blood vessel in the patient's body. As a result, the operation of retracting the cover 3 becomes even easier, and the convenience of using the medical device 5 can be further improved.

[0059] Furthermore, in this embodiment, when the rod-shaped member 42 (engagement portion 420) and the base-end member 43 engage with each other and the base-end member 43 moves in the proximal direction (when the entire stent 21 is deployed and its diameter is expanded), the gap G between the tip of the shaft 11 and the rear end of the buffer member 40 is eliminated. As a result, for example, when the members of the medical device 5 excluding the stent graft 2 (the catheter 1, cover 3, buffer members 40, rod-shaped members 41 and 42, base-end member 43, grip 120, etc.) are each removed from the patient's body, the following occurs.

[0060] That is, during such removal, displacement of the placement position of the stent graft 2 due to the pushing and pulling of each component (the operation of moving each component in the forward and backward directions after the entire stent 21 is expanded) is avoided. Specifically, for example, if the above-mentioned gap G is provided during the pushing and pulling of each component, the distal end of the shaft 11 may become caught in the mesh structure of the stent 21, causing the placement position of the stent graft 2 to be displaced. In contrast, in the present embodiment, since the gap G is eliminated during the pushing and pulling of each component, such displacement of the placement position of the stent graft 2 is avoided. As a result, it is possible to further improve the convenience of using the medical device 5.

[0061] Additionally, in this embodiment, a portion of the shaft 11, including the tip, is subjected to low-friction processing, which results in the following: When the cover 3 is retracted, friction between the vicinity of the tip of the shaft 11 and the cover 3 (folded-back portion 33) is reduced. As a result, the operation of retracting the cover 3 becomes even easier, and the convenience of using the medical device 5 can be further improved.

[0062] <2. Modifications> Although the present disclosure has been described above by way of the embodiments, the present disclosure is not limited to the above embodiments and various modifications are possible.

[0063] For example, the configuration (shape, placement position, size, number, material, etc.) of each member described in the above embodiment is not limited, and other shapes, placement 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 of this cover 3 may be other shapes, placement positions, sizes, numbers, materials, etc.

[0064] Furthermore, in the above embodiment, the rod-shaped member 41 and the buffer member 40 are provided with through-holes H1 and H2 as guidewire lumens, respectively, but, for example, neither through-hole H1 nor H2 may be provided. In addition, in the above embodiment, an example is described in which low-friction processing is applied to a portion of the shaft 11, including the distal end, but this example is not limiting. That is, for example, the entire region of the shaft 11 from the distal end to the proximal end may be low-friction processed, or the entire region of the shaft 11 may not be low-friction processed.

[0065] Furthermore, in the above embodiment, the portion including the graft 22 and the cuff 23 has been described as an example of an "additional structural portion" in the stent graft of the present disclosure, but this is not limiting. 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 above-mentioned "additional structural portion."

[0066] Furthermore, in the above embodiment, the case where the inner portion 31 and the outer portion 32 of the cover 3 are integrated with each other via the folded portion 33 in the initial state has been described, but this is not limiting. That is, for example, in the initial state, the inner portion and the outer portion may be separate from each other and may be connected (coupled) by a separate folded portion (coupled portion).

[0067] Additionally, in the above embodiment, specific examples have been given to explain the internal configuration of handle 12 (the configuration of rod-shaped members 41, 42, engaging portion 420, base end member 43, stop portion 121, etc.), but the internal configuration of handle 12 is not limited to the examples explained in the above embodiment. Also, the configuration of grip 120 provided on the base end side of handle 12 is not limited to the examples explained in the above embodiment, and in some cases, for example, grip 120 may not be provided.

[0068] Furthermore, in the above embodiment, a specific example of a method for placing a stent graft 2 using a medical device 5 is described, but the method for placing a stent graft 2 is not limited to the example described in the above embodiment.

[0069] Furthermore, in the above-described embodiment, a medical device applied to treatment of the thoracic aorta, including the distal aortic arch and the proximal descending aorta, has been described as an example, but the present disclosure is not limited to this example. That is, the medical device of the present disclosure can also be applied to treatment of blood vessels such as other arteries (e.g., the ascending aorta, the thoracic-abdominal aorta, the abdominal aorta, the iliac arteries, the femoral arteries, etc.).

[0070] Furthermore, the various configuration examples described above may be applied in any combination.

[0071] The effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0072] The present disclosure may also be configured as follows. (1) A stent graft and a shaft extending along an axial direction and inserted into the stent graft; a buffer member disposed on the tip side of the shaft; a cover that covers at least a portion of the stent graft; a retraction mechanism that retracts the cover into the shaft from between the tip of the shaft and the rear end of the buffer member; A medical device comprising: (2) a handle disposed on a proximal end side of the shaft; a first rod-shaped member connected to the buffer member and extending through the shaft into the handle; a base end member connected to the vicinity of the base end of the first rod-shaped member and configured to be movable in a base end direction within the handle when the retraction mechanism retracts the cover; Further equipped with The medical device according to (1) above. (3) The retraction mechanism includes: a second rod-shaped member connected to the base end side of the cover located inside the shaft and engaging with the base end member when the retraction is performed to a predetermined position; The medical device according to (2) above. (4) The second rod-shaped member and the base-end member are engaged with each other, and when the base-end member moves in the base-end direction, a gap between the tip of the shaft and the rear end of the buffer member is eliminated. The medical device according to (3) above. (5) The handle has a stop that stops the proximal member from moving in the proximal direction. A medical device according to any one of (2) to (4) above. (6) The first rod-shaped member has a first through-hole that penetrates along the axial direction, the buffer member has a second through hole penetrating along the axial direction, The first through hole and the second through hole are in communication with each other. A medical device according to any one of (2) to (5) above. (7) A portion of the shaft, including the tip, is subjected to low-friction processing to reduce friction. A medical device according to any one of (1) to (6) above. (8) The stent graft comprises: a stent at least partially covered by the cover; Additional structural parts and It is composed of A medical device according to any one of (1) to (7) above. [Explanation of symbols]

[0073] 1...catheter, 11...shaft, 110...tubular member, 111...covering layer, 12...handle, 120...grip, 121...stopper, 2...stent graft, 21...stent, 22...graft, 220...branch structure, 23...cuff portion, 3...cover, 31...inner portion, 32...outer portion portion, 33...folded portion, 40...cushioning member, 41, 42...rod-shaped members, 420...engagement portion, 43...proximal member, 5...medical device, 80...felt, 9...artery, 9B...arch branch, W...wire, G...gap, H1, H2...through holes.

Claims

1. A stent graft and a shaft extending along an axial direction and inserted into the stent graft; a buffer member disposed on the tip side of the shaft; a cover that covers at least a portion of the stent graft; a retraction mechanism that retracts the cover into the shaft from between the tip of the shaft and the rear end of the buffer member; a handle disposed on a proximal end side of the shaft; a first rod-shaped member connected to the buffer member and extending through the shaft into the handle; a base end member connected to the vicinity of the base end of the first rod-shaped member and configured to be movable in a base end direction within the handle when the retraction mechanism retracts the cover; Equipped with The retraction mechanism includes: a second rod-shaped member connected to the base end side of the cover located inside the shaft and engaging with the base end member when the retraction is performed to a predetermined position; Medical devices.

2. The second rod-shaped member and the base-end member are engaged with each other, and when the base-end member moves in the base-end direction, a gap between the tip of the shaft and the rear end of the buffer member is eliminated. The medical device of claim 1 .

3. The handle has a stop that stops the proximal member from moving in the proximal direction. The medical device of claim 1 .

4. A stent graft, a shaft extending along an axial direction and inserted into the stent graft; a buffer member disposed on the tip side of the shaft; a cover that covers at least a portion of the stent graft; a retraction mechanism that retracts the cover into the shaft from between the tip of the shaft and the rear end of the buffer member; a handle disposed on a proximal end side of the shaft; a first rod-shaped member connected to the buffer member and extending through the shaft into the handle; a base end member connected to the vicinity of the base end of the first rod-shaped member and configured to be movable in a base end direction within the handle when the retraction mechanism retracts the cover; Equipped with The handle has a stop that stops the proximal member from moving in the proximal direction. Medical devices.

5. The first rod-shaped member has a first through-hole that penetrates along the axial direction, the buffer member has a second through hole passing through it along the axial direction, The first through hole and the second through hole are in communication with each other. The medical device according to any one of claims 1 to 4.

6. With the stent graft held within the cover, A predetermined gap is provided between the shaft and the buffer member. The medical device according to any one of claims 1 to 4.

7. A portion of the shaft, including the tip, is subjected to low-friction processing to reduce friction. The medical device according to any one of claims 1 to 4.

8. The stent graft comprises: a stent at least partially covered by the cover; Additional structural parts and It is composed of The medical device according to any one of claims 1 to 4.

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