Stent and method for imaging stent

Abstract

Provided are a stent that makes it possible to distinguish and identify a marker provided on a wire from other markers, and a method for imaging the stent.　A stent 1 is inserted into and delivered through a catheter C, and is used for an application of expanding a stenotic area in a biological lumen. The stent 1 comprises a wire 2 and stent bodies 10, 20 connected to the distal side of the wire 2. The stent 1 further comprises a first wire marker part 31 provided on the wire 2, and a second wire marker part 32 provided on the wire 2 and located distal to the first marker 31 with a space therebetween in the axial direction of the stent 1.

Description

Stent and stent imaging method

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to stents and methods of imaging stents.

[0002] Conventionally, a device using a stent (hereinafter also referred to as a thrombus retrieval stent) for removing and retrieving a thrombus formed in a blood vessel has been known (see Patent Document 1). This thrombus retrieval stent is configured in a form suitable for retrieving a thrombus, and in order to entangle the thrombus in the stent and retrieve it, the stent, which has expanded in diameter within the blood vessel, is pulled toward the catheter (proximal side), whereby the stent is retrieved together with the thrombus.

[0003] On the other hand, when a stenosis occurs in a biological lumen having a luminal structure such as a blood vessel, trachea, or intestine, the use of a stent (hereinafter also referred to as a stenosis-dilation stent) has been considered to ensure patency of the lesion by expanding the lumen at the stenotic site. A stenosis-dilation stent is configured in a shape suitable for dilating a stenotic site and is placed in contact with the inner wall of the biological lumen with a predetermined expansion force. Therefore, if a stenosis-dilation stent is unintentionally displaced while in contact with the inner wall of the biological lumen during the stent deployment process or insertion into a catheter, the inner wall of the biological lumen may be damaged if the stent is unintentionally displaced (hereinafter, unintentional displacement is also referred to as "accidental displacement"). Therefore, it is important that a stenosis-dilation stent be operated in a manner that prevents accidental displacement of the stent body when deployed.

[0004] Furthermore, when a stent is placed in a luminal structure, in order to confirm the position of the stent within the luminal structure, an opaque member (so-called marker) that is highly opaque to radiation such as X-rays is provided on the stent (see Patent Document 2). With such a stent, the opaque member provided on the stent can be visually confirmed by irradiating it with radiation, thereby improving the ease of stent application.

[0005] A wire is connected to a stenosis dilatation stent proximal to the stent body, and when the position of the stent body needs to be changed, the wire is moved proximally or distally. Therefore, if a marker is also provided on this wire, it would be possible to check whether a force is acting to accidentally move the stent body.

[0006] It is also believed that it will be possible to confirm whether the stent main body is contained in the catheter (reduced diameter state) or completely extended from the catheter (expanded diameter state) based on the relative positional relationship between the marker on the wire and the marker on the catheter.

[0007] JP 2021-106928 A JP 2014-171893 A

[0008] However, if the markers on the wire are provided in the same form as the markers on the stent body as in Patent Document 2, it may be difficult to distinguish and recognize the markers on the wire and the markers on the stent body.

[0009] An object of the present disclosure is to provide a stent and a method for imaging a stent that can distinguish and confirm markers provided on a wire from other markers.

[0010] The present disclosure solves the above-mentioned problems by the following means: For ease of understanding, the following description will be given with reference numerals corresponding to the embodiments of the present disclosure, but the present disclosure is not limited to these.

[0011] The first disclosure is a stent (1, 1B) that is inserted into a catheter (C) and delivered, and is used to dilate a narrowed portion in a biological lumen, the stent (1, 1B) comprising a wire (2) and a stent body (10, 20) connected to the distal side of the wire (2), a first marker portion (31, 31B) provided on the wire (2), and a second marker portion (32) provided on the wire (2) and spaced distally from the first marker portion (31, 31B) in the axial direction of the stent (1, 1B).

[0012] The second disclosure relates to a stent (1, 1B) that is inserted into a catheter (C) and delivered to be used for dilating a narrowed portion in a biological lumen, the stent (1, 1B) comprising: a wire (2); a first stent body (10) that is connected to the distal side of the wire (2) and has a plurality of first cells (12) that are each composed of a plurality of first struts (11) arranged in the circumferential direction and in the central axis direction; and a second stent body (20) that has a plurality of second cells (22) that are each composed of a plurality of second struts (21) that are continuous in the circumferential direction and in the central axis direction, and at least a region that dilates the biological lumen is inserted into the first stent body (10), the stent (1, 1B) comprising: a first marker portion (31, 31B) provided on the wire (2); and a second marker portion (32) provided on the wire (2) and spaced distally from the first marker portion (31, 31B) in the axial direction of the stent (1, 1B).

[0013] The third disclosure is a stent (1, 1B) according to claim 1 or claim 2, wherein the first marker portion (31, 31B) is configured to be longer than the second marker portion (32).

[0014] The fourth disclosure is a stent (1B) as described in claim 3, wherein the first marker portion (31B) is provided continuously or at intervals toward the proximal side of the wire (2) within a range of 20 mm or more from the distal end position of the first marker portion toward the proximal side.

[0015] The fifth disclosure is an imaging method for capturing an image of a stent (1, 1B) described in claim 1 or claim 2 within a biological lumen, the imaging method including: an imaging step during contraction of the stent (1, 1B) in which the first marker portion (31, 31B) and the second marker portion (32) are captured when the stent (1, 1B) is contracted at a planned position for expansion within the biological lumen; and an imaging step during expansion of the stent (1, 1B) in which the first marker portion (31, 31B) and the second marker portion (32) are captured when the stent (1, 1B) is expanded.

[0016] A sixth disclosure is an imaging method for a stent (1, 1B) according to claim 5, wherein a catheter marker (CM) having high radiopacity is provided at or near the distal end of the catheter (C), and in the imaging step during diameter reduction, the catheter marker (CM) is imaged together with the first marker (31, 31B) and the second marker (32) in a state where the catheter marker (CM) is located distal to the second marker (32), and in the imaging step during diameter expansion, the catheter marker (CM) is imaged together with the first marker (31, 31B) and the second marker (32) in a state where the catheter marker (CM) overlaps with a separation portion (33) located between the first marker (31, 31B) and the second marker (32), or in a state where the catheter marker (CM) is located proximal to the separation portion (33).

[0017] The seventh disclosure is a method for imaging a stent (1, 1B) as described in claim 6, in which, when the stent (1, 1B) is taken out of the catheter (C) and expanded in diameter, the imaging step at the time of diameter reduction is performed, and then the catheter (C) is moved proximally while maintaining the position of the stent (1, 1B) to perform the imaging step at the time of diameter expansion, and thereafter, when the stent (1, 1B) is housed in the catheter (C), the catheter (C) is moved distally while maintaining the position of the stent (1, 1B) to perform the imaging step at the time of diameter reduction again.

[0018] The eighth disclosure relates to a method for dilating a stricture in a biological lumen using a stent (1, 1B), the stent (1, 1B) being inserted into a catheter (C) and delivered, and used to dilate a stricture in a biological lumen, the stent (1, 1B) comprising a wire (2) and a stent body (10, 20) connected to the distal side of the wire (2), a first marker portion (31, 31B) provided on the wire (2), and a second marker portion (32) provided on the wire (2) and spaced distally from the first marker portion (31, 31B) in the axial direction of the stent (1, 1B). The method includes delivering the stent (1, 1B) housed in the catheter (C) in a contracted state through the biological lumen together with the catheter (C) to a planned position (P) for expansion of the biological lumen; performing a transition imaging step of withdrawing the catheter (C) proximally and starting expansion of the stent (1, 1B) from the distal side to capture moving X-ray images of the first marker portion (31, 31B) and the second marker portion (32); completing the expansion of the stent (1, 1B); and re-accommodating the expanded stent (1, 1B) into the catheter (C).

[0019] The ninth disclosure relates to a method for expanding a stricture in a biological lumen using a stent (1, 1B), the stent (1, 1B) comprising: a wire (2); a first stent body (10) connected to the distal side of the wire (2) and having a plurality of first cells (12) each consisting of a plurality of first struts (11) arranged in the circumferential direction and in the central axis direction; and a second stent body (20) in which a plurality of second cells (22) each consisting of a plurality of second struts (21) are continuous in the circumferential direction and in the central axis direction, and in which at least a region for expanding the biological lumen is inserted into the first stent body (10), and a first marker portion (31, 31B) provided on the wire (2) and a first marker portion (31, 31B) arranged in the axial direction of the stent (1, 1B). and a second marker portion (32) provided on the wire (2) and spaced distally from the first marker portion (31, 31B), and the method includes: delivering the stent (1, 1B) housed in the catheter (C) in a reduced diameter state together with the catheter (C) through the body lumen to a planned position (P) for expansion of the body lumen; performing a transition imaging step of pulling out the catheter (C) proximally and starting expansion of the stent (1, 1B) from the distal side to capture moving images of the X-ray transmission of the first marker portion (31, 31B) and the second marker portion (32); completing the expansion of the stent (1, 1B); and re-accommodating the expanded stent (1, 1B) into the catheter (C).

[0020] According to the present disclosure, it is possible to provide a stent and a method for imaging a stent that can distinguish and confirm a marker provided on a wire from other markers.

[0021] 1 is a side view of the stent 1 of the first embodiment. FIG. 2 is a perspective view of the stent 1 shown in FIG. 1. FIG. 3 is a virtual development view of a portion of the first stent body 10 of the first embodiment. FIG. 4 is a virtual development view of a portion of the second stent body 20 of the first embodiment. FIG. 5 is a virtual development view of a portion of the stent 1 of the first embodiment. FIG. 6 is a view explaining the outer diameter D1 of the first stent body 10 alone. FIG. 7 is a view explaining the outer diameter D2 of the second stent body 20 alone. FIG. 8 is a view showing the process of inserting the second stent body 20 into the first stent body 10. FIG. 9 is a cross-sectional view of the stent 1 cut at the position of arrow s1-s1 in FIG. 1. FIG. 11 is a view explaining the internal state of the stent 1 when it is bent. FIG. 12 is an exploded and enlarged view of the vicinity of the end portion on the distal LD2 side of the wire 2. FIG. 13 is a schematic view showing an example of an image captured in a diameter-reduced imaging step in which an image of the second stent marker portion 121 is captured when the stent 1 is in a diameter-reduced state at a planned diameter-reduced position in a biological lumen. 1 is a diagram showing an example of an image captured in a transition imaging step of imaging the second stent marker portion 121 in a state in which the stent 1 is in the middle of transitioning from a contracted state to an expanded state at a planned diameter expansion position in a biological lumen. FIG. 2 is a diagram showing an example of an image captured in a diameter expansion imaging step of imaging the second stent marker portion 121 in a state in which the stent 1 is expanded at a diameter expansion position in a biological lumen. FIG. 3 is a diagram showing an example of an image captured in a diameter contraction imaging step. FIG. 4 is a diagram showing an example of an image captured in a diameter expansion imaging step. FIG. 5 is a diagram showing an example of an image captured in a diameter expansion imaging step. FIG. 6 is a diagram showing an example of an image captured in a diameter expansion imaging step. 1A is a schematic diagram showing a state in which a force is acting to push the wire 2 toward the distal LD2 side when the stent 1B of the second embodiment is in a radially expanded state. FIG. 1B is a schematic diagram showing a state in which a force is acting to push the wire 2 toward the distal LD2 side when the stent 1B of the second embodiment is in a radially expanded state.

[0022] Hereinafter, an embodiment of a stent will be described. Note that the drawings attached to this specification are all schematic diagrams, and the shape, scale, aspect ratio, etc. may be modified or exaggerated from the actual product. Furthermore, in the drawings, hatching indicating the cross section of a member may be omitted as appropriate.

[0023] In this specification, terms specifying the shape, geometric conditions, and the degree of these, such as "orthogonal" and "direction," include not only the strict meaning of the terms but also the range in which they can be considered to be nearly orthogonal and the range in which they can be considered to be roughly in that direction. In this specification, the axial direction (longitudinal direction) LD refers to the side closer to the practitioner (proximal) as the LD1 side (or proximal LD1 side), and the side farther from the practitioner (distal) as the LD2 side (or distal LD2 side), and the direction orthogonal to the axial direction LD is referred to as the radial direction RD. Also, in this specification, the direction in which the cells are arranged is referred to as the circumferential direction OD. The circumferential direction may refer to the radial direction RD or a direction inclined relative to the radial direction RD.

[0024] (First embodiment) Fig. 1 is a side view of a stent 1 of the first embodiment. Fig. 2 is a perspective view of the stent 1 shown in Fig. 1. Fig. 3A is a virtual developed view of a portion of a first stent body 10 of the first embodiment. Fig. 3B is a virtual developed view of a portion of a second stent body 20 of the first embodiment. Fig. 3C is a virtual developed view of a portion of a stent 1 of the first embodiment. Fig. 4A is a view illustrating the outer diameter D1 of a single first stent body 10. Fig. 4B is a view illustrating the outer diameter D2 of a single second stent body 20. Fig. 5 is a view illustrating the process of inserting the second stent body 20 into the first stent body 10. Fig. 6 is a cross-sectional view of the stent 1 taken at the position of arrows s1-s1 in Fig. 1.

[0025] In the drawings, to make it easier to distinguish between the first stent body 10 and the second stent body 20, the struts of the first stent body 10 are shown in black, and the struts of the second stent body 20 are shown in white. In this specification, etc., the term "cell" refers to the portion surrounded by struts that form the stent. The "cells" may have the same shape and size, or may have different sizes. The term "strut" refers to the portion made of the wire-like material. In this specification, etc., the opening of a cell is also referred to as the "opening portion," and the portion where struts of adjacent cells are connected or overlapped is also referred to as the "overlapping portion."

[0026] The stent 1 of the first embodiment can be used, for example, to dilate a narrowed or blocked blood vessel by being housed in a catheter C (see FIGS. 9 to 11 ) and being pushed out of the catheter in the lumen of the blood vessel to expand its diameter. The stent 1 is used in applications where it is temporarily placed in the blood vessel and then retrieved from the body, but it can also be used in applications where it is left in the blood vessel without being retrieved from the body. When used in such applications, it is preferable that the wire 2 and the stent 1 can be separated by an operator's operation.

[0027] As shown in Figures 1 and 2, the stent 1 has a substantially cylindrical shape in an expanded state. The stent 1 has a long, thin cylindrical shape in a contracted state. A wire 2 is connected to the end of the stent 1 on the proximal LD1 side. The method for connecting the proximal end of the stent 1 to the wire 2 is not particularly limited as long as it is a connection method used in general medical devices, and examples include welding, UV bonding, and infiltration with silver solder.

[0028] The practitioner advances or retreats the stent 1 within the catheter or blood vessel by pushing or pulling the wire 2 via an ex vivo operating unit (not shown) connected to the proximal LD1 side of the wire 2. Furthermore, as shown in Figures 9 to 14 (described later), the stent 1 can be extended from the catheter C and expanded, or retracted into the catheter C, by pulling (retreating) or pushing (advancing) the catheter C without moving the wire 2 (stent 1).

[0029] The stent 1 comprises a first stent body 10 and a second stent body 20, each of which has a substantially cylindrical structure. The stent 1 is a two-layer stent in which the second stent body 20 is inserted into the first stent body 10 at least in a region that dilates the narrowed portion of a biological lumen. Here, the region that dilates the narrowed portion of a biological lumen refers to a region that substantially contributes to dilating the narrowed portion during use, and in the case of the stent 1 of this embodiment, it refers to a region that is expanded into a substantially cylindrical shape in the expanded state shown in Figures 1 and 2. The above-mentioned "at least" means that the second stent body 20 must be inserted into the first stent body 10 in the region that dilates the narrowed portion. The range in which the second stent body 20 is inserted into the first stent body 10 is not limited to the region that substantially expands the narrowed area described above (in this embodiment, the region that expands into an approximately cylindrical shape), and in this embodiment, the second stent body 20 is inserted into the first stent body 10 up to the point where it is connected to the wire 2.

[0030] The first stent body 10 and the second stent body 20 are not connected to each other in the radial direction. Specifically, the first stent body 10 and the second stent body 20 are indirectly connected via the wire 2, but are not connected in other regions. Therefore, the first stent body 10 and the second stent body 20 can flexibly deform independently. Furthermore, even in the expanded diameter state, the first stent body 10 and the second stent body 20 are merely in close contact with each other in the radial direction and are not linked (connected) together in the radial direction. Therefore, the first stent body 10 and the second stent body 20 are independently deformable and do not restrict each other's deformation.

[0031] The proximal LD1 side of the first stent body 10, the proximal LD1 side of the second stent body 20, and the distal LD2 side of the wire 2 are directly connected. Here, "directly connected" means, for example, that the proximal LD1 side of the first stent body 10 is connected to the distal LD2 side of the wire 2, and that the proximal LD1 side of the second stent body 20 is connected to the distal LD2 side of the wire 2. In this case, the position where the proximal LD1 side of the first stent body 10 is connected to the wire 2 and the position where the proximal LD1 side of the second stent body 20 is connected to the wire 2 may be the same as or different from each other. In this embodiment, the position where the proximal LD1 side of the first stent body 10 is connected to the wire 2 is located proximal to the position where the proximal LD1 side of the second stent body 20 is connected to the wire 2.

[0032] The proximal LD1 side of the first stent body 10, the proximal LD1 side of the second stent body 20, and the distal LD2 side of the wire 2 may be indirectly connected. Here, "indirectly connected" refers to, for example, a configuration in which the proximal LD1 side of the first stent body 10 is connected to the distal LD2 side of the wire 2 and the proximal LD1 side of the first stent body 10 is connected to the proximal LD1 side of the second stent body 20 (or a configuration in which the connections between the two stent bodies are reversed). In this case, the proximal LD1 side of the second stent body 20 is indirectly connected to the wire 2 via the proximal LD1 side of the first stent body 10. Alternatively, the proximal LD1 side of the first stent body 10 and the proximal LD1 side of the second stent body 20 may be connected via a pipe-shaped sleeve (not shown) inserted around the distal LD2 side of the wire 2. In this case, the proximal LD1 side of the first stent body 10 and the proximal LD1 side of the second stent body 20 are indirectly connected to the distal LD2 side of the wire 2 via the sleeve. Thus, in this specification, "indirectly connected" includes a configuration in which one of the proximal LD1 side of the first stent body 10 or the proximal LD1 side of the second stent body 20 is directly connected to the wire 2, and the other stent body is indirectly connected to the wire 2 via the directly connected stent body. Examples of methods for connecting the proximal end of each stent body to the wire 2 include welding, UV bonding, impregnation with silver solder, etc., but are not particularly limited as long as they are connection methods used in general medical devices.

[0033] As will be described later, the stent 1 of the first embodiment is produced by inserting a second stent body 20, which has an outer diameter larger than that of the first stent body 10 in its natural state, in a contracted state into the first stent body 10. As a result, the second stent body 20 constantly presses the first stent body 10 outward in the radial direction RD, thereby more firmly adhering the first stent body 10 and the second stent body 20 to each other.

[0034] 1 , the ends of the first stent body 10 and the second stent body 20 on the proximal LD1 side are tapered and connected to the wire 2. This restricts the second stent body 20 from moving in the axial direction relative to the first stent body 10.

[0035] As shown in Fig. 3A , the first stent body 10 has a plurality of outer cells (first cells) 12 surrounded by first struts 11 and arranged in the circumferential direction OD. In the first stent body 10, the plurality of outer cells 12 are arranged in the axial direction LD. That is, the first stent body 10 has a pattern in which the plurality of outer cells 12 are arranged in the circumferential direction OD and the axial direction LD. Openings 13 are formed in the outer cells 12. Furthermore, the outer cells 12 adjacent to each other in the circumferential direction OD are connected at overlapping portions 14.

[0036] The overlapping portion 14 is where the first struts 11 of four adjacent outer cells 12 are connected. The overlapping portion 14 has a generally rectangular shape that is elongated in the axial direction LD. Each first strut 11 is connected to one of the four corners of the overlapping portion 14. Each first strut 11 has a curved portion 15 formed at the portion where it is connected to the overlapping portion 14. Therefore, when the expanded stent 1 is bent into a generally U-shape (see FIG. 7 ), each first strut 11 connected to the overlapping portion 14 can be deformed independently. This allows the outer cells 12 arranged in the circumferential direction OD to bend more flexibly. In this way, the first stent body 10 allows the outer cells 12 arranged in the circumferential direction OD to bend flexibly, resulting in excellent shape conformability and diameter reduction properties.

[0037] As shown in Fig. 3B , the second stent body 20 has a plurality of inner cells (second cells) 22 surrounded by second struts 21 arranged in the circumferential direction OD. The inner cells 22 are arranged continuously in the axial direction LD. That is, the second stent body 20 has a pattern in which the inner cells 22 are arranged in the circumferential direction OD and the axial direction LD. Adjacent inner cells 22 are connected at overlapping portions 24.

[0038] The overlapping portion 24 is a portion where the second struts 21 of four adjacent inner cells 22 are connected. The overlapping portion 24 has a generally rectangular shape that is elongated in the axial direction LD. Each second strut 21 is connected to one of the four corners of the overlapping portion 24. Each second strut 21 has a curved portion 25 formed at the portion where it is connected to the overlapping portion 24. Therefore, when the expanded stent 1 is bent into a generally U-shape, each second strut 21 connected to the overlapping portion 24 can be deformed independently. This allows the inner cells 22 arranged in the circumferential direction OD to bend more flexibly. In this way, the second stent body 20 allows the inner cells 22 arranged in the circumferential direction OD to bend more flexibly, and therefore has excellent shape conformability and diameter reduction ability.

[0039] 3A and 3B, in the stent 1 of the first embodiment, the outer cell 12 and the inner cell 22 have, for example, the same size, shape, and arrangement except for the distal LD2 side. That is, in the first embodiment, the pattern shown in Fig. 3A and the pattern shown in Fig. 3B are substantially the same except for the distal LD2 side.

[0040] As shown in FIG. 3C , the first stent body 10 and the second stent body 20 are arranged in their natural state such that the overlapping portions 24 of the inner cells 22 (second stent body 20) overlap the openings 13 of the outer cells 12 (first stent body 10). Specifically, the overlapping portions 24 of one inner cell 22 overlap the openings 13 of one outer cell 12. This increases the strut density throughout the stent, thereby increasing the surface area of ​​the stent 1. Furthermore, the stent 1 of this embodiment has excellent shape-following ability and diameter reduction properties because the overlapping portions 14 of the outer cells 12 have the configuration shown in FIG. 3A and the overlapping portions 24 of the inner cells 22 have the configuration shown in FIG. 3B . Furthermore, because the outer cells 12 and the inner cells 22 of the stent 1 have the above-described configurations, it is possible to easily insert the stent 1 into a catheter after it has been reduced in diameter, and also to easily insert the stent 1 into a catheter again after it has been expanded in a blood vessel.

[0041] In the first embodiment, the relationship between the outer diameter D1 of the first stent body 10 before assembly and the outer diameter D2 of the second stent body 20 before assembly is D1<D2. Therefore, as shown in Fig. 5 , the second stent body 20A, which is obtained by reducing the diameter of the second stent body 20, is inserted into the first stent body 10. Then, as shown in Fig. 6 , the self-expansion force of the second stent body 20 causes the second stent body 20 to adhere closely to the inside of the first stent body 10 in the circumferential direction OD.

[0042] Therefore, it is unlikely that the first stent body 10 and the second stent body 20 will be misaligned relative to each other in the axial direction LD (see Figure 1) of the stent 1. Note that, for ease of understanding, Figure 5 shows only the annular cell rows arranged in the circumferential direction in each stent body, and the number of cells is shown to be greater than in other figures so that the tubular shape can be easily understood.

[0043] In the first embodiment, the second stent body 20 inserted into the first stent body 10 in a contracted state constantly presses the first stent body 10 outward in the radial direction RD. Therefore, the first stent body 10 and the second stent body 20 can be brought into close contact with each other even if they are not connected to each other in the radial direction. Furthermore, because the first stent body 10 and the second stent body 20 of the stent 1 are not connected to each other in the radial direction, the first stent body 10 and the second stent body 20 can flexibly deform independently. Furthermore, the stent 1 has an expansion force that is the sum of the expansion force of the first stent body 10 and the expansion force of the second stent body 20. Therefore, the ratio of expansion force to surface area can be increased compared to a single-layer stent.

[0044] The stent 1 (first stent body 10, second stent body 20) may be made of a highly biocompatible material. While not particularly limited, a material with superelastic properties, such as a nickel-titanium (Ni-Ti) alloy, is preferred. The first stent body 10 and the second stent body 20 can be fabricated, for example, by laser processing a substantially cylindrical tube made of the above material.

[0045] The stent 1 may be loaded with a drug such as a physiologically active substance (such as a drug that suppresses intimal hyperplasia), and specifically, may carry the drug so that the drug is eluted in the lumen structure.

[0046] The first stent body 10 and the second stent body 20 are fabricated, for example, by laser processing a tube with an outer diameter of approximately 0.4 to 3 mm to form a mesh pattern, and then stretching it radially to achieve the desired diameter. As described above, a two-layer stent 1 can be fabricated by inserting the second stent body 20 into the first stent body 10. This two-layer stent 1 is housed in the lumen of a catheter in a state where its diameter is reduced in the radial direction from its natural state. If the stent 1 is made of an elastic material such as a superelastic alloy or a shape-memory alloy, pushing the stent 1 housed in the catheter outward will cause it to expand in diameter by its own expansive force.

[0047] Next, the effect of the stent 1 of the first embodiment when it is temporarily placed in a curved blood vessel and then removed will be described.

[0048] The stent 1 of this embodiment is a stenosis dilation stent used to dilate a stenotic lumen in order to ensure patency of the lesion site when a stenosis occurs in a biological lumen. Therefore, the stent 1 is placed by contacting the inner wall of the biological lumen with a predetermined expansion force. Therefore, if the stent 1 is accidentally moved while in contact with the inner wall of the biological lumen, there is a risk of damaging the inner wall of the biological lumen. Therefore, it is important to operate the stent 1 in a manner that prevents accidental movement of the stent body when the stent body is deployed. Because the first struts 11 and the second struts 21 move with the expansion and contraction of the stent 1, the markers on the first struts 11 and the second struts 21 are suitable for checking the expansion and contraction of the stent 1. However, the markers on the first struts 11 and the second struts 21 are not suitable for checking the movement of the entire stent 1. A wire 2 is connected to the stent 1, and the amount of movement of the entire stent 1 coincides with the amount of movement of the wire 2. Therefore, in this embodiment, a marker is provided on the wire 2, and by checking the wire 2, it is possible to check the movement state of the entire stent 1.

[0049] The stent 1 of the first embodiment includes, as markers, a first wire marker portion (first marker portion) 31, a second wire marker portion (second marker portion) 32, a first stent marker portion 111, and a second stent marker portion 121. These markers serve as landmarks for confirming the position and state of the stent 1 under radiographic observation within a tubular organ such as a blood vessel, and are formed from a material that is highly radiopaque (highly contrast-enhancing). Here, radiopaque refers to a material that is more radiopaque than portions of the stent 1 other than the markers (other portions that do not have radiopaque properties) under radiographic observation during a procedure, and is radiopaque to the extent that the markers can be observed as an image. "Radiopaque" is necessary to obtain "visibility" and "contrast" under radiographic observation.

[0050] First, we will explain the configuration of the first wire marker portion 31, the second wire marker portion 32, the first stent marker portion 111, and the second stent marker portion 121 (hereinafter simply referred to as markers) of this embodiment, as well as the configuration of conventionally known markers that can be used as the various markers described in the second embodiment.

[0051] Highly radiopaque materials that can be used as markers may be metals or synthetic resins. Examples of metal materials include gold, tantalum, platinum, tungsten, iridium, platinum tungsten, etc., and alloys thereof. Other examples include radiopaque polymer materials to which a radiopaque filler or the like has been added. When the marker is configured as a linear member, for example, a composite wire having a core material made of the aforementioned metal material coaxially within a nickel-titanium wire can be used.

[0052] Furthermore, as a method for attaching the marker to the stent 1, any processing method that has been conventionally used to place a marker on a known stent can be used as appropriate, such as soldering laser welding of gold-tin or silver-tin, mechanical crimping, or adhesive bonding with resin.

[0053] Specific examples of forms that can be used as the markers of this embodiment include "ring markers," "coil markers," "crimp markers," "radiopaque wire markers," "radiopaque struts or radiopaque wires," etc. Note that the above-mentioned exemplary forms and their names are classified and named by the applicant for convenience, and various conventionally known marker forms can be used.

[0054] A ring marker is, for example, a marker component that is highly radiopaque and has a ring or cylindrical shape, and is fixed to a strut or the like by soldering, adhesive, or the like.

[0055] A coil marker is a marker in which a linear member made of a highly radiopaque material is formed into a coil shape, and the marker is wound around a strut or the like and fixed by soldering, adhesive, or the like.

[0056] A crimp marker is, for example, a marker component having a high degree of radiopacity, such as a ring shape or a roughly cylindrical shape, that is fixed to a strut or the like by crimping. Note that if a crimp marker is used for the first wire marker portion 31 and the second wire marker portion 32, the crimping may cause the marker to become eccentric, making it difficult to insert the marker into the catheter, and since the wire portion does not have a slit, it may be difficult to ensure strength. Therefore, it is desirable to use a ring marker or a coil marker for the first wire marker portion 31 and the second wire marker portion 32.

[0057] A radiopaque wire marker is a marker made of a highly radiopaque wire that is placed along or wrapped around a strut or the like, and the end of the wire is fixed to the strut by soldering, adhesive, etc. Radiopaque wire markers are similar in form to the coil markers described above, but are classified differently from coil markers in that they are not wound densely enough to be called a coil.

[0058] A radiopaque strut or radiopaque wire is a strut or wire that is formed from a highly radiopaque material, or a strut or wire that is formed by plating or coating a highly radiopaque material onto the entire or partial surface of the strut.

[0059] 8 is an exploded, enlarged view of the vicinity of the distal LD2 end of the wire 2. Two first struts 11 are arranged opposite each other at the proximal LD1 end 11a of the first struts 11, and the distal LD2 side of the wire 2 is inserted through the portion where the first struts 11 face each other and welded to the end.

[0060] The first wire marker portion 31 is a coil marker formed by coiling a linear member made of a highly radiopaque material, and is fixed by welding in a position covering the end portion 11a on the proximal LD1 side of the first strut 11. The first wire marker portion 31 is configured as a tightly wound coil near the center of the first wire marker portion 31, and as a coil wound with spaces between the ends near both ends of the first wire marker portion 31. This configuration prevents the wire 2 from bending.

[0061] The proximal LD1 side end 21a of the second strut 21 is arranged so that two second struts 21 face each other, and the distal LD2 side end of the wire 2 is located at the part where the second struts 21 face each other and is fixed by welding.

[0062] The second wire marker portion 32 is a ring marker formed by soldering a marker component formed into a cylindrical shape from a highly radiopaque material to the strut, and is fixed by solder in a position covering the end portion 21a on the proximal LD1 side of the second stent body 20. The second wire marker portion 32 is disposed at a distance closer to the distal LD2 side than the first wire marker portion 31. The region between the first wire marker portion 31 and the second wire marker portion 32 is hereinafter referred to as the separation portion 33. The length of the separation portion 33 in the LD direction is desirably, for example, 0.6 mm or more and 2.0 mm or less.

[0063] The first wire marker portion 31 and the second wire marker portion 32 are positioned at a predetermined interval in the axial direction LD. This arrangement allows the positions of the proximal ends LD1 of the first stent body 10 and the second stent body 20 to be correctly confirmed. Furthermore, as will be described later, they can serve as markers for the retraction position of the catheter C (see FIG. 9, etc.) during radial expansion.

[0064] Furthermore, the first wire marker portion 31 is configured to have a longer length in the LD direction than the second wire marker portion 32. Therefore, the first wire marker portion 31 and the second wire marker portion 32 can be clearly distinguished and visually recognized. It is desirable that the length of the first wire marker portion 31 in the LD direction be 1.5 times or more longer than the second wire marker portion 32 in order to make them easier to distinguish and visually recognize. It is even more desirable that the length of the first wire marker portion 31 in the LD direction be two or more times longer than the second wire marker portion 32. For example, it is desirable that the length of the second wire marker portion 32 be 0.5 mm or more and 1.5 mm or less, and that the length of the first wire marker portion 31 in the LD direction be 1.5 times or more longer than the second wire marker portion 32.

[0065] The first stent marker portion 111 is formed in a substantially square pipe shape and is a crimped marker that is crimped to the end portion on the distal LD2 side of the first stent body 10. In this embodiment, the first stent body 10 has two end portions on the distal LD2 side, and therefore the first stent marker portion 111 is provided in two locations.

[0066] The second stent marker portion 121 is formed in a substantially square pipe shape, and is a crimped marker that is crimped to the end portion on the distal LD2 side of the second stent main body 20 in a similar manner to the first stent marker portion 111. In this embodiment, since the second stent main body 20 has two end portions on the distal LD2 side, the first stent marker portion 111 is provided in two locations.

[0067] In X-ray observation, it is difficult to visually distinguish and identify whether it is the first stent marker portion 111 or the second stent marker portion 121 based on the shape of the marker alone. Therefore, in this embodiment, the first stent marker portion 111 is arranged at a different position in the axial direction LD of the stent from the second stent marker portion 121. More specifically, the second stent marker portion 121 is arranged more distally LD2 than the first stent marker portion 111. In this embodiment, the inner cell 22 located most distally LD2 is made longer toward the distal LD2 side than the other cells (the inner cell 22 and the outer cell 12 located more proximal LD1), so that the second stent marker portion 121 is arranged more distally LD2 than the first stent marker portion 111.

[0068] With this configuration, when the first stent marker portion 111 and the second stent marker portion 121 are simultaneously observed under X-ray observation, it is possible to distinguish between the first stent marker portion and the second stent marker portion based on their appearance, and each can be visually distinguished and observed. Therefore, the positions of the distal LD2 side ends of the first stent body 10 and the second stent body 20 and the appropriate state of diameter expansion or contraction can be correctly confirmed.

[0069] In this embodiment, the first stent marker portion 111 and the second stent marker portion 121 are marker members having the same shape and size, and are arranged such that the second stent marker portion 121 is positioned more distally LD2 than the first stent marker portion 111 in the axial direction LD of the stent 1. That is, the first stent marker portion 111 and the second stent marker portion 121 are arranged in different positions in the axial direction of the stent 1 over the entire marker. However, this is not limiting, and for example, the first stent marker portion 111 and the second stent marker portion 121 may be arranged in a position in the axial direction of the stent 1 that is different from the second stent marker portion 121 over a portion of the marker. More specifically, for example, the axial length of the second stent marker portion 121 may be configured to be longer than the axial length of the first stent marker portion 111, so that the position of either the proximal LD1 end portion or the distal LD2 end portion, or both, of each stent marker portion 121 is different from the other. Furthermore, it is not necessary for all of the first stent marker portions 111 and second stent marker portions 121 to have the configuration exemplified in this embodiment. For example, a portion of the first stent marker portion 111 may be positioned at the same position in the axial direction LD as the second stent marker portion 121. Similarly, a portion of the second stent marker portion 121 may be positioned at the same position in the axial direction LD as the first stent marker portion 111.

[0070] By deploying the stent 1 of the first embodiment at a lesion in the vascular lumen, the vascular lumen is expanded, ensuring patency of the lesion and allowing blood flow to resume. By removing (retrieving) the stent 1 from the vascular lumen after a predetermined period of time, complications due to the placement of the stent, such as restenosis, re-occlusion, and thrombosis, can be prevented. When expanding or contracting the stent 1, the first stent marker portion 111 and the second stent marker portion 121 can be distinguished from each other, allowing the conditions of the first stent body 10 and the second stent body 20 to be properly grasped, enabling safer and more reliable treatment. Furthermore, the stent 1 of the first embodiment has excellent shape-following properties, resulting in high blood vessel protection. The stent 1 of the first embodiment can be used not only for the treatment of blood vessels, but also for the treatment of luminal structures in general, such as the esophagus and large intestine.

[0071] The stent 1 of the first embodiment can also be used to treat cerebral vasospasm. Note that the stents of other embodiments described below also exhibit the same effects as the stent 1 of the first embodiment.

[0072] (Imaging Method) Next, an imaging method for imaging the stent of the present invention for observation with radiation will be described. Fig. 9 is a diagram schematically illustrating an example of an image captured in a diameter reduction imaging step in which the second stent marker portion 121 is imaged when the stent 1 is in a diameter-reduced state at a planned diameter expansion position in a biological lumen. Fig. 10 is a diagram schematically illustrating an example of an image captured in a transition imaging step in which the second stent marker portion 121 is imaged when the stent 1 is in the middle of transitioning from a diameter-reduced state to an expanded state at a planned diameter expansion position in a biological lumen. Fig. 11 is a diagram schematically illustrating an example of an image captured in a diameter expansion imaging step in which the second stent marker portion 121 is imaged when the stent 1 is in a diameter-expanded state at a diameter expansion position in a biological lumen. Fig. 12 is a diagram illustrating an example of an image captured in the diameter reduction imaging step. Fig. 13 is a diagram illustrating an example of an image captured in the transition imaging step. Fig. 14 is a diagram illustrating an example of an image captured in the diameter expansion imaging step.

[0073] The catheter C is provided on the distal LD2 side with a catheter marker CM that is highly radiopaque, allowing its position to be visualized under X-ray observation. The catheter marker CM is provided at the end of the catheter C on the distal LD2 side or near the end of the catheter C on the distal LD2 side. Note that "near the end of the catheter C on the distal LD2 side" does not necessarily mean the exact end, but also includes a case where the catheter marker CM is provided at a position within 1.5 mm of the end. Note that the examples shown in Figures 9 to 14 illustrate an example in which the second stent marker 121 is shifted distally LD2ward relative to the first stent marker 111 by a larger amount than in Figure 1 of the first embodiment.

[0074] When expanding a blood vessel, the stent 1, housed in a catheter C in a contracted state as shown in FIGS. 9 and 12 , is delivered through the blood vessel together with the catheter C to a planned expansion position P. The planned expansion position P is, for example, a portion of the blood vessel where the inner diameter is smaller than other portions due to stenosis. At this time, the practitioner uses an X-ray imaging device to capture moving X-ray images of the first stent marker portion 111 and the second stent marker portion 121 (diameter contraction imaging step). The first stent marker portion 111 and the second stent marker portion 121 are located on the distal LD2 side of the stent 1 of the first embodiment, allowing the relative positional relationship between these and the catheter marker portion CM to be confirmed. This allows visual confirmation that the stent 1 is properly housed in the catheter C and delivered to the desired position.

[0075] Next, while preventing accidental movement of the wire 2 in the LD direction to maintain the position of the stent 1 within the blood vessel, the catheter C is withdrawn toward the proximal LD1 side, and the stent 1 begins to expand from the distal LD2 side (see FIGS. 10 and 13 ). At this time, the practitioner uses an X-ray imaging device to capture X-ray transmission dynamic images of the first stent marker portion 111 and the second stent marker portion 121, and the first wire marker portion 31 and the second wire marker portion 32 (transition imaging step). From the imaging results, it is possible to confirm the relative positions of the first stent marker portion 111 and the second stent marker portion 121 and the catheter marker portion CM, as well as the relative positions of the first wire marker portion 31 and the second wire marker portion 32 and the catheter marker portion CM. Furthermore, because the second stent marker portion 121 is positioned distally LD2 relative to the first stent marker portion 111, the first stent marker portion 111 and the second stent marker portion 121 can be distinguished from each other. Therefore, it is possible to visually confirm that the expansion of the stent 1 is progressing appropriately, that the position of the stent 1 has not accidentally moved, and that the expansion of the stent 1 has begun.

[0076] When the expansion of the stent 1 is complete, the state shown in Figures 11 and 14 is reached. At this time, the practitioner uses an X-ray imaging device to capture moving X-ray images of the first stent marker portion 111 and the second stent marker portion 121, and the first wire marker portion 31 and the second wire marker portion 32 (expansion imaging step). As in the transition imaging step, in the expansion imaging step, the second stent marker portion 121 is positioned more distally (LD2) than the first stent marker portion 111, making it possible to distinguish and recognize the first stent marker portion 111 and the second stent marker portion 121. In addition, a predetermined gap is provided between the first wire marker portion 31 and the second wire marker portion 32, forming a separation portion 33. If the catheter marker portion CM is located at a position overlapping the separation portion 33 or at a position closer to the proximal LD1 side than the separation portion 33, it can be confirmed that the catheter C has been retracted reliably from the range of diameter expansion of the stent 1 (the range between the first stent body and the second stent body). Therefore, by performing the imaging step during diameter expansion with the catheter marker portion CM located at a position overlapping the separation portion 33 or at a position closer to the proximal LD1 side than the separation portion 33, it can be visually confirmed that the diameter expansion of the stent 1 has been completed appropriately at the appropriate position.

[0077] When the expanded stent 1 is to be re-housed in the catheter C, the above operations and imaging steps are performed in reverse order. In both imaging steps when re-housed, the catheter C is pushed toward the distal LD2 side while preventing accidental movement of the wire 2 in the LD direction. Whether the wire 2 is moving or not can be easily and reliably determined by observing the first wire marker portion 31, the second wire marker portion 32, and the separation portion 33.

[0078] As described above, according to the first embodiment, the stent 1 is configured such that the first wire marker portion 31 and the second wire marker portion 32 are spaced a predetermined distance apart by the separation portion 33. The length of the separation portion 33 is different from the distance between the first stent marker portion 111 and the second stent marker portion 121. Furthermore, the length of the first wire marker portion 31 is longer than the length of the second wire marker portion 32, and the separation portion 33 is provided between markers of different lengths, resulting in a distinctive visual arrangement of the markers. Therefore, the first wire marker portion 31 and the second wire marker portion 32 can be distinguished from the first stent marker portion 111 and the second stent marker portion 121. Similarly, the first wire marker portion 31 and the second wire marker portion 32 can be distinguished from the catheter marker portion CM by being spaced a predetermined distance apart. Furthermore, when transitioning from a reduced-diameter state to an expanded-diameter state, by moving the catheter marker portion CM to a position where it overlaps with the separation portion 33, it is possible to confirm that the catheter C has moved to a position where the stent can be sufficiently expanded. It is also conceivable that the catheter marker portion CM and the first wire marker portion 31 or the second wire marker portion 32 may be difficult to distinguish from each other if they overlap. However, even in such cases, the separation portion 33 makes it easy to determine that the catheter marker portion CM is in a position where it overlaps with the separation portion 33. Furthermore, the first wire marker portion 31 is configured to be longer in the LD direction than the second wire marker portion 32. Therefore, the first wire marker portion 31 and the second wire marker portion 32 can be clearly distinguished from each other visually, and the orientation of the proximal and distal sides can be easily determined, even in a blood vessel that repeatedly bends.

[0079] 15 is a schematic side view of a stent 1B of a second embodiment. The stent 1B of the second embodiment has a similar configuration to the stent 1 of the first embodiment, except that the shape of the first wire marker portion 31B is different from that of the first wire marker portion 31 of the first embodiment. Therefore, parts that perform the same functions as those of the first embodiment described above are given the same reference numerals, and redundant explanations will be omitted as appropriate.

[0080] The first wire marker portion 31B is a marker in the form of a radiopaque wire, formed by closely adhering a highly radiopaque material to the surface of a required area of ​​the wire 2 by plating, coating, or the like. Note that the first wire marker portion 31B may be formed as a coil marker, as in the first embodiment, or may be formed as a marker in other forms.

[0081] Furthermore, the distal end position of the first wire marker portion 31B of the second embodiment on the distal LD2 side is provided at a position where a separation portion 33 is provided between the first wire marker portion 31 and the second wire marker portion 32, similar to the first wire marker portion 31 of the first embodiment. The rear end position of the first wire marker portion 31B on the proximal LD1 side is provided continuously to the rear end position of the wire 2 on the proximal LD1 side. Therefore, the stent 1B of the second embodiment can be visualized up to the rear end position of the wire 2 on the proximal LD1 side under observation using radiation. This configuration allows early detection of forces pushing or pulling the stent 1B acting on the wire 2. This point will be explained below using schematic diagrams.

[0082] Fig. 16 is a schematic diagram showing an ideal state in which the stent 1B of the second embodiment is expanded and no unnecessary force is being applied to the wire 2. Fig. 17 is a schematic diagram showing a state in which the stent 1B of the second embodiment is expanded and a force pulling the wire 2 toward the proximal LD1 side is acting. Fig. 18 is a schematic diagram showing a state in which the stent 1B of the second embodiment is expanded and a force pushing the wire 2 toward the distal LD2 side is acting. Fig. 19 is a schematic diagram showing a state in which the stent 1B of the second embodiment is expanded and a force pushing the wire 2 toward the distal LD2 side is acting. Note that the catheter is omitted from Figs. 16 to 19 to make the state of the wire 2 easier to see.

[0083] Like the stent 1 of the first embodiment, the stent 1B of the second embodiment is a stenosis dilatation stent used to dilate the lumen of a stenosis that occurs in a biological lumen to ensure patency of the lesion. Therefore, if the stent 1B is accidentally moved while in contact with the inner wall of the biological lumen, it may damage the inner wall of the biological lumen. Therefore, it is important to operate the stent 1 in such a way that the position of the stent body is not accidentally moved when it is deployed.

[0084] When a force FLD1 pulling the wire 2 toward the proximal LD1 side is applied while the stent 1B is in a radially expanded state, for example, the wire 2 moves in a direction approaching the inside of the curved blood vessel inner wall (arrow M1 in FIG. 17 ), and the state changes from that of FIG. 16 to that of FIG. 17 . This change is characteristic of the application of a force FLD1 pulling the wire 2 toward the proximal LD1 side. Therefore, by observing the state of the wire 2 (first wire marker portion 31B) under observation using radiation, it is possible to quickly determine that a force FLD1 pulling the wire 2 toward the proximal LD1 side has been applied.

[0085] Furthermore, when a force FLD2 is applied to the wire 2 toward the distal LD2 side while the stent 1B is in a radially expanded state, the wire 2 moves, for example, in a direction approaching the outside of the curved blood vessel inner wall (arrow M2 in FIG. 18 ), changing from the state shown in FIG. 16 to the state shown in FIG. 17 . Alternatively, it is also possible that a portion of the wire 2 (the portion indicated by arrow K in FIG. 19 ) is significantly bent, as shown in FIG. 19 . Such a change is characteristic of the application of a force FLD2 that presses the wire 2 toward the distal LD2 side. Therefore, by observing the state of the wire 2 (first wire marker portion 31B) under radiological observation, it is possible to quickly determine that a force FLD2 that presses the wire 2 toward the distal LD2 side has been applied.

[0086] In order to quickly detect the force acting on the wire 2 as described above, it is not necessary for the first wire marker portion 31B to be provided up to the end portion on the proximal LD1 side of the wire 2. For example, the first wire marker portion 31B may be provided in a range of 20 mm or more from the end portion on the distal LD2 side, where the separation portion 33 is provided between the first wire marker portion 31B and the second wire marker portion 32, toward the proximal LD1 side of the wire 2. Furthermore, for example, the first wire marker portion 31B may be provided in a range of 200 mm or less from the end portion on the distal LD2 side, where the separation portion 33 is provided between the first wire marker portion 31B and the second wire marker portion 32, toward the proximal LD1 side of the wire 2.

[0087] As described above, according to the second embodiment, the first wire marker portion 31B is provided in a range of 20 mm or more from the end portion on the distal LD2 side, where the separation portion 33 is provided between the first wire marker portion 31B and the second wire marker portion 32, toward the proximal LD1 side of the wire 2. This makes it possible to quickly detect the application of a pulling or pushing force to the wire 2. This makes it possible to prevent the first stent body 10 and the second stent body 20 from accidentally moving while rubbing against the inner wall of a blood vessel or the like, enabling safer treatment.

[0088] (Modifications) The present disclosure is not limited to the above-described embodiment, and various modifications and variations are possible, and these are also within the scope of the present disclosure.

[0089] (1) In each embodiment, a specific marker shape has been described as an example. However, the specific shape of the marker in each embodiment is not limited to the example shown in the embodiment, and various types of conventionally known marker shapes can be used. For example, a ring marker may be replaced with a coil marker, or a radiopaque wire may be replaced with a coil marker.

[0090] (2) In each embodiment, the strut portion also has a marker. However, the present invention is not limited to this. For example, the marker on the strut portion may be omitted.

[0091] (3) In each embodiment, a stent having a two-layer structure has been described as an example. However, the present invention is not limited to this, and a stent having a single-layer structure may also be used.

[0092] (4) In the second embodiment, an example has been described in which the rear end position of the first wire marker portion 31B on the proximal LD1 side is provided continuously up to the rear end position on the proximal LD1 side of the wire 2. However, this is not limiting, and for example, the first wire marker portion 31B may be provided discontinuously. Here, discontinuously means, for example, a form in which a plurality of first wire marker portions 31B are arranged at intervals in a dashed line shape.

[0093] The embodiments and modifications may be used in combination as appropriate, but detailed description thereof will be omitted. The present disclosure is not limited to the embodiments described above.

[0094] DESCRIPTION OF SYMBOLS 1, 1B Stent 2 Wire 10 First stent body 11 First strut 11a End 12 Outer cell 13 Opening portion 14 Overlapping portion 15 Curved portion 20, 20A Second stent body 21 Second strut 21a End 22 Inner cell 23 Opening portion 24 Overlapping portion 25 Curved portion 31, 31B First wire marker portion 32 Second wire marker portion 33 Separated portion 111 First stent marker portion 121 Second stent marker portion C Catheter CM Catheter marker portion

Claims

1. A stent that is inserted into a catheter for delivery and used for the purpose of expanding a stenosis in a biological lumen, comprising: a wire; and a stent body connected to the distal side of the wire, and comprising: a first marker portion provided on the wire; and a second marker portion provided on the wire and spaced distally from the first marker portion in the axial direction of the stent.

2. A stent that is inserted into a catheter for delivery and used for the purpose of expanding a stenosis in a biological lumen, comprising: a wire; a first stent body connected to the distal side of the wire and having a plurality of first cells formed by a plurality of first struts arranged in the circumferential and central axis directions; and a second stent body having a plurality of second cells formed by a plurality of second struts arranged in the circumferential and central axis directions, and at least a region for expanding the biological lumen being inserted into the first stent body, and comprising: a first marker portion provided on the wire; and a second marker portion provided on the wire and spaced distally from the first marker portion in the axial direction of the stent.

3. The stent according to claim 1 or 2, wherein the first marker portion is configured to be longer in length than the second marker portion.

4. The stent according to claim 3, wherein the first marker portion is provided in a range of 20 mm or more proximally from the distal end position of the first marker portion, continuously or with intervals, toward the proximal side of the wire.

5. An imaging method for imaging an image of the stent according to claim 1 or 2 in a biological lumen, comprising: a reduced-diameter imaging step of imaging the first marker portion and the second marker portion in a state where the stent is reduced in diameter at a planned diameter-expansion position in the biological lumen; and an expanded-diameter imaging step of imaging the first marker portion and the second marker portion in a state where the stent is expanded in diameter.

6. In the method for imaging a stent according to claim 5, a catheter marker portion having high radiopacity is provided at or near the distal end of the catheter. In the imaging step during diameter reduction, the catheter marker portion is imaged together with the first marker portion and the second marker portion in a state where the catheter marker portion is located more distally than the second marker portion. In the imaging step during diameter expansion, the catheter marker portion is imaged together with the first marker portion and the second marker portion in a state where the catheter marker portion overlaps a separation portion located between the first marker portion and the second marker portion, or in a state where the catheter marker portion is located more proximally than the separation portion. A method for imaging a stent.

7. In the method for imaging a stent according to claim 6, when the stent is taken out of the catheter and expanded, after performing the imaging step during diameter reduction, the catheter is moved proximally while maintaining the position of the stent to perform the imaging step during diameter expansion. Then, when the stent is accommodated in the catheter, the catheter is moved distally while maintaining the position of the stent to perform the imaging step during diameter reduction again. A method for imaging a stent.

Images