Intravascular device

Abstract

An intravascular device (1) is configured such that a first end section (1a) is disposed in a blood vessel of an organism, and an electrode for detection or stimulation of nerve tissue located outside the blood vessel is provided to the first end section (1a). The intravascular device (1) includes: an electrically-conductive wire member (10); at least one electrode member (20) that is provided on the first end section (1a) side and that is electrically connected to the wire member (10); and difference reduction sections (30, 40) that reduce a level difference caused by an outer diameter difference between the outer diameter of the electrode member (20) and the outer diameter of the wire member (10). The electrical resistance between the electrode member (20) and a second end section (1b) of the wire member (10), which is on the side opposite from the first end section (1a), is 100 Ω or less.

Description

Intravascular Devices

[0001] SUMMARY The present disclosure relates to intravascular devices used to sense or stimulate neural tissue activity.

[0002] Conventionally, when measuring brain waves in living organisms such as animals and humans, transcranial measurement has been performed, in which electrodes are attached to the scalp to measure brain waves. While this method allows for easy measurement of brain waves, it has the following drawbacks. That is, since only information from the surface of the brain can be obtained, it is only possible to measure brain waves near the surface of the brain, and it is not possible to measure brain waves generated deep within the brain. In addition, brain waves are attenuated as they pass through the skull, making accurate measurement difficult.

[0003] As a method for overcoming such drawbacks, Patent Document 1 discloses a device used for detecting or stimulating activity of nervous tissue.

[0004] Japanese Patent Application Laid-Open No. 2022-121975

[0005] However, in the device of Patent Document 1, the electrodes are exposed from the sides of the core material and the insulator, making it difficult to stably manufacture this electrode in an extremely thin external shape that can be inserted into a cerebral blood vessel, for example. Also, when the electrode has a spiral portion, it has poor deliverability within the blood vessel.

[0006] An object of the present disclosure is to provide an intravascular device that is used to detect or stimulate activity of nervous tissue, has excellent deliverability to blood vessels, and has high sensitivity for detection or stimulation.

[0007] 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.

[0008] The first disclosure is an intravascular device (1, 1B, 1C) having a first end (1a) placed in a blood vessel of a living organism and comprising an electrode on the first end (1a) side for detecting or stimulating activity of neural tissue located outside the blood vessel, the intravascular device (1, 1B, 1C) comprising: a conductive linear delivery member (10); at least one electrode member (20, 21, 22) provided on the first end (1a) side and electrically connected to the linear delivery member (10); and a step reduction section (30, 40, 70) that reduces a step caused by a difference in outer diameter between the electrode member (20, 21, 22) and the linear delivery member (10), wherein the electrical resistance value between the electrode member (20, 21) and a second end (1b) of the linear delivery member (10) opposite the first end (1a) is 100 Ω or less.

[0009] The second disclosure is an intravascular device (1, 1C) described in the first disclosure, wherein the step reduction portion (30, 40) includes at least one of a coil-shaped member (30) arranged around the linear delivery member (10), a stranded wire member (80) arranged around or along the linear delivery member (10), and a resin tubular member (40) arranged around the linear delivery member (10).

[0010] The third disclosure is an intravascular device (1, 1C) according to the second disclosure, in which at least a portion of the coil-shaped member (30) is inserted into the electrode member (20, 21).

[0011] The fourth disclosure is an intravascular device (1, 1C) according to the second or third disclosure, wherein at least a portion of the tubular member (40) is externally inserted onto the coiled member (30).

[0012] The fifth disclosure is an intravascular device (1D) described in the first disclosure, wherein the electrode member (22) and the linear delivery member (10) are arranged at a distance from each other, and the electrode member (22) and the linear delivery member (10) are electrically connected by a conductor (80).

[0013] A sixth disclosure is an intravascular device (1D) according to the fifth disclosure, wherein the conductor (80) is a coil or a stranded wire.

[0014] A seventh disclosure is an intravascular device (1, 1B) according to any one of the first to fourth disclosures, wherein the electrode member (20) is in the form of a metal wire wound in a spiral shape.

[0015] The eighth disclosure is an intravascular device (1, 1B, 1C) described in any one of the first to fifth disclosures, wherein the electrode member (20, 21) and the linear delivery member (10) are welded together.

[0016] A ninth disclosure is an intravascular device (1, 1B, 1C) according to any one of the first to sixth disclosures, wherein the intravascular device (1, 1B, 1C, 1D) is an intravascular device (1, 1B, 1C, 1D) that is left in a blood vessel for one day or more.

[0017] A tenth disclosure is an intravascular device (1, 1B, 1C) according to any one of the first to seventh disclosures, wherein the blood vessel in which the intravascular device (1, 1B, 1C, 1D) is placed is a cerebral vein.

[0018] According to the present disclosure, it is possible to provide an intravascular device that is used to detect or stimulate activity of nervous tissue, has excellent deliverability to blood vessels, and has high sensitivity for detection or stimulation.

[0019] 1 is a diagram showing a first embodiment of an intravascular device 1 according to the present disclosure; FIG. 2 is an enlarged view of the vicinity of a first end 1a of the intravascular device 1; FIG. 3 is a cross-sectional view of the intravascular device 1 taken along the arrow A-A in FIG. 2; FIG. 4 is a cross-sectional view of the intravascular device 1B of a second embodiment taken along the same line as in FIG. 3 of the first embodiment; FIG. 5 is a cross-sectional view of the intravascular device 1C of a third embodiment taken along the same line as in FIG. 3 of the first embodiment; and FIG. 6 is a cross-sectional view of the intravascular device 1D of a fourth embodiment taken along the same line as in FIG. 3 of the first embodiment.

[0020] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0021] (First embodiment) Figure 1 is a diagram showing a first embodiment of an intravascular device 1 according to the present disclosure. Note that Figures shown below, including Figure 1, are schematic diagrams, and the size and shape of each part are exaggerated or omitted as appropriate for ease of understanding. In addition, the following description will be given using specific numerical values, shapes, materials, etc., but these can be changed as appropriate.

[0022] The intravascular device 1 of this embodiment is used to detect or stimulate neural activity in a living organism, such as an animal or human. The intravascular device 1 is formed in a flexible, elongated string shape. A first end 1a is placed in a blood vessel (typically a cerebral blood vessel) of the living organism, and a second end 1b is electrically connected to a measuring device, oscillator, or the like (not shown). The intravascular device 1 is inserted into a cerebral vein through a catheter used in conventional cerebrovascular surgery. As described below, the electrodes are extremely thin and flexible, are attached to a wire member, and have a smooth outer shape. Therefore, unlike a stent, they do not have an expansive force. Furthermore, they have excellent sliding properties relative to the catheter, resulting in excellent deliverability to the cerebral blood vessels. Furthermore, because the wire member is prevented from contacting the blood vessel (particularly in this embodiment, the string-like wire member in its natural state barely contacts the blood vessel wall), adverse events are unlikely to occur even when the device is left in place for a long period of time. Therefore, the device can be safely left in the blood vessel for one day or more (specifically, two days or more, five days or more, seven days or more, two weeks or more, or one month or more).

[0023] Fig. 2 is an enlarged view of the vicinity of the first end 1a of the intravascular device 1. Fig. 3 is a cross-sectional view of the intravascular device 1 taken along the position of the arrow A-A in Fig. 2. The intravascular device 1 includes a wire member 10, an electrode member 20, an inner coil 30, a tubular member 40, a tip portion 50, and a connecting portion 60.

[0024] The wire member 10 is a conductive linear delivery member extending from the first end 1a to the second end 1b of the intravascular device 1. The wire member is flexible and linear (or cord-like or rod-like) overall. Unlike a cylindrical body, it does not have a lumen. The linear delivery member may be a straight wire member as in this embodiment, a stranded wire member, or a member in the form of a coil or multi-strand coil. However, a straight wire member is preferable to reduce electrical resistance. The wire member 10 in this embodiment is a straight wire made of an alloy of Ni (nickel) and Ti (titanium). The wire member 10 is not limited to the above-mentioned materials and may be made of, for example, stainless steel. The large-diameter portion 10b of the wire member 10 on the second end 1b side may have a diameter of, for example, approximately 0.25 mm. The small-diameter portion 10a of the wire member 10 near the first end 1a is thinner than the large-diameter portion 10b, and may have a diameter of, for example, approximately 0.05 mm. The difference in outer diameter between the small-diameter portion 10a and the large-diameter portion 10b is connected by a conical surface portion 10c, whose outer diameter gradually changes. While the inclination of the conical surface portion 10c is exaggerated in the figure to show a larger rate of change, the rate of change in outer diameter at the conical surface portion 10c may be smaller than shown. An insulating coating is formed on the surface of the wire member 10. For example, a PTFE (polytetrafluoroethylene) coating can be used as this insulating coating. Alternatively, a tube or heat-shrinkable tube made of PTFE, silicone, polyimide, or the like may be used instead of the insulating coating. Note that no insulating coating is provided near the tip of the wire member 10 (near the first end 1a). This is to allow for welding of the tip portion 50, which will be described later.

[0025] The electrode member 20 is disposed around the wire member 10 on the first end 1a side and is electrically connected to the wire member 10. The electrode member 20 is composed of a conductor exposed on its surface to detect weak currents, such as brain waves, generated within the body of a human or animal, and to transmit currents generated by an oscillator into the body. In this embodiment, the electrode member 20 is formed into a tightly coiled shape by spirally winding a metal wire made of an alloy of Pt (platinum) and W (tungsten). Using an alloy containing Pt (platinum) for the electrode member 20 improves visibility when observed with X-rays. The coiled shape of the electrode member 20 also provides flexibility, improving delivery to blood vessels and reducing the risk of damaging blood vessels. The diameter of the electrode member 20 can be, for example, 0.1 mm or more and 0.28 mm or less, and in this embodiment, it is 0.25 mm. Furthermore, in order to properly detect and transmit current, the longitudinal length of the portion of the electrode member 20 exposed to the outside is desirably 1 mm or more, and more desirably 2 mm or more. In this embodiment, the longitudinal length of the electrode member 20 is 3 mm. Furthermore, the distal end region 20a (the end on the first end 1a side) of the electrode member 20 may be configured to have a smaller outer diameter than the other portions of the electrode member 20 (the portions closer to the second end 1b than the distal end) to improve deliverability. In this embodiment, the distal end region 20a of the electrode member 20 is configured to have a smaller outer diameter than the other portions of the electrode member 20.

[0026] The inner coil 30 is a coil-shaped member provided around the wire member 10. The inner coil 30 has an outer diameter slightly smaller than the inner diameter of the electrode member 20, and is inserted into the electrode member 20 in the area where the electrode member 20 is provided on the tip side (first end 1a side) of the inner coil 30. That is, in this area, the inner coil 30 is disposed between the wire member 10 and the electrode member 20. The longitudinal range (length) of the inner coil 30 inserted into the electrode member 20 should be at least a length that ensures stable positioning of the inner coil 30. In this embodiment, the inner coil 30 is inserted into the electrode member 20 over the entire area where the electrode member 20 is provided. In addition, in this embodiment, the longitudinal length (total length) of the inner coil 30 is 40 mm. In addition, the rear end side (second end 1b side) of the inner coil 30 is inserted into the tubular member 40. In the present embodiment, the inner coil 30 is formed by spirally winding a metal wire made of an alloy of Pt (platinum) and W (tungsten), similar to the electrode member 20. By using an alloy containing Pt (platinum) for the inner coil 30, visibility when observed with X-rays can be improved, similar to the electrode member 20. Furthermore, using the same material for the inner coil 30 and the electrode member 20 can improve weldability when welding the distal end portion 50, which will be described later. While the present embodiment illustrates an example in which the inner coil 30 is made of an alloy of Pt (platinum) and W (tungsten), similar to the electrode member 20, the inner coil 30 may be formed of other materials, such as stainless steel. Furthermore, the inner coil 30 is not formed as a tightly packed coil, but as a spaced coil. This allows the inner coil 30 to be flexible, improves delivery to blood vessels, and reduces the risk of damaging the blood vessels.

[0027] The tubular member 40 is a resin member provided around the wire member 10 and is fitted around the inner coil 30 in the area where the inner coil 30 is provided. In this embodiment, the inner coil 30 is not insulated, and therefore, the tubular member 40 is fitted around the inner coil 30 to insulate the inner coil 30. In this embodiment, the length in the longitudinal direction (total length) of the tubular member 40 is 200 mm. The tip side (first end 1a side) of the tubular member 40 is disposed close to the rear end (end on the second end 1b side) of the electrode member 20. In addition, the rear end side (second end 1b side) of the tubular member 40 is located midway along the conical surface portion 10c of the wire member 10. The tubular member 40 is preferably made of a tube or heat-shrinkable tube made of a fluororesin such as PTFE, PFA (Poly Tetra Fluoro Ethylene), or FEP (Fluorinated Ethylene Propylene), silicone, or polyimide, and in this embodiment, a heat-shrinkable tube made of a fluororesin is used. The outer diameter of the tubular member 40 is approximately the same as the outer diameter of the electrode member 20.

[0028] The inner coil 30 and the tubular member 40 function as a step reducer that reduces a step caused by the difference in outer diameter between the outer diameter of the electrode member 20 and the outer diameter of the wire member 10. That is, the inner coil 30 is inserted around the wire member 10 and inserted inside the electrode member 20, thereby reducing the step caused by the difference in outer diameter between the outer diameter of the electrode member 20 and the outer diameter of the wire member 10. Furthermore, because the tubular member 40 is inserted around the inner coil 30, the step caused by the difference in outer diameter between the outer diameter of the electrode member 20 and the outer diameter of the wire member 10 is substantially eliminated, and the surface of the electrode member 20 and the surface of the tubular member 40 become substantially flush.

[0029] The tip portion 50 is provided at the most distal end on the first end 1a side and is formed in a substantially hemispherical shape. The tip portion 50 is formed by welding the electrode member 20 and the wire member 10 together. That is, the tip portion 50 is formed from an alloy in which the electrode member 20 and the wire member 10 are melted and mixed. The provision of the tip portion 50 electrically joins the electrode member 20 and the wire member 10 together. Note that in this embodiment, in addition to the electrode member 20 and the wire member 10, the inner coil 30 is also welded to the tip portion 50; however, the inner coil 30 does not necessarily have to be welded to the tip portion 50.

[0030] In order to properly detect and transmit current from and to tissue outside the blood vessel, the electrical resistance between the electrode member 20 and the rear end (the end on the second end 1b side) of the wire member 10 is preferably 100 Ω or less, and more preferably 75 Ω or less. In this embodiment, the wire member 10 is straight and is welded to the electrode member 20 at the tip 50, thereby achieving a very low resistance of 70 Ω or less.

[0031] The connecting portion 60 connects the rear end portion (the end portion on the second end portion 1b side) of the electrode member 20 to the end portion on the first end portion 1a side of the tubular member 40. The connecting portion 60 can be made of an adhesive such as an ultraviolet-curing type, a two-component epoxy adhesive, a cyanoacrylic instant adhesive, or a silicone adhesive.

[0032] The intravascular device 1 of the first embodiment described above can be used for various purposes. For example, if the intravascular device 1 of this embodiment is appropriately positioned in a cerebral blood vessel near each of the left and right hemispheres of the brain and electroencephalograms are detected, it can be used to identify epileptic foci and detect epileptic seizures. Furthermore, if the intravascular device of the present invention is appropriately positioned at the causative site and electrical stimulation is supplied, it can be used to treat diseases whose causative site is deep in the brain (epilepsy, depression, involuntary movements due to Parkinson's disease, persistent vegetative state, etc.).

[0033] As described above, the intravascular device 1 of the first embodiment can be easily manufactured due to its simple configuration using the wire member 10, the electrode member 20, the inner coil 30, and the tubular member 40. Furthermore, the intravascular device 1 of the first embodiment can provide an intravascular device that has excellent deliverability to blood vessels and high sensitivity to detection or stimulation.

[0034] Second Embodiment Figure 4 is a cross-sectional view of an intravascular device 1B of a second embodiment taken at the same position as in Figure 3 of the first embodiment. The intravascular device 1B of the second embodiment has the same configuration as the intravascular device 1 of the first embodiment, except that a second tubular member 70 is disposed instead of the inner coil 30. Therefore, parts that perform the same functions as in the first embodiment described above are denoted by the same reference numerals, and redundant explanations will be omitted as appropriate.

[0035] The second tubular member 70 has an outer diameter slightly smaller than the inner diameter of the electrode member 20. The second tubular member 70 is inserted into the electrode member 20 at the distal end (first end 1a) of the second tubular member 70, i.e., the electrode member 20 is located within the electrode member 20. In other words, the second tubular member 70 is disposed between the wire member 10 and the electrode member 20 within this region. The proximal end (second end 1b) of the second tubular member 70 is inserted into the tubular member 40. The second tubular member 70 is preferably made of a tube or heat-shrinkable tube made of a fluororesin such as PTFE, PFA (Poly Tetra Fluoro Ethylene), or FEP (Fluorinated Ethylene Propylene), or a silicone or polyimide tube. In this embodiment, a fluororesin tube is used. The inner diameter of the second tubular member 70 is slightly larger than the outer diameter of the small-diameter portion 10a of the wire member 10, at least before assembly. When a heat-shrinkable tube is used for the second tubular member 70 , the inner diameter of the second tubular member 70 after shrinkage becomes equal to the outer diameter of the small diameter portion 10 a of the wire member 10 .

[0036] In the second embodiment described above, the second tubular member 70 is placed instead of the inner coil 30, which improves dimensional stability and further improves pushability, thereby improving deliverability to blood vessels and facilitating access to any blood vessel.

[0037] 5 is a cross-sectional view of an intravascular device 1C of a third embodiment taken at the same position as in FIG. 3 of the first embodiment. The intravascular device 1C of the third embodiment has the same configuration as the intravascular device 1 of the first embodiment, except for the configuration of the electrode member 21. Therefore, parts that perform the same functions as in the first embodiment described above are denoted by the same reference numerals, and redundant explanations will be omitted as appropriate.

[0038] The electrode member 21 of the third embodiment is provided in the same position as the electrode member 20 of the first embodiment, but differs from the electrode member 20 of the first embodiment in that it has a cylindrical shape. The electrode member 21 of the third embodiment can be made of the same material as the electrode member 20 of the first embodiment.

[0039] The intravascular device 1C of the third embodiment has a cylindrical electrode member 21, which can suppress corrosion that tends to occur in areas where metals come into contact with each other. Therefore, even when the intravascular device 1C of the third embodiment is placed in a blood vessel for a long period of time, adverse effects such as a decrease in detection capability and signal transmission capability due to corrosion can be prevented.

[0040] 6 is a cross-sectional view of an intravascular device 1D of a fourth embodiment taken at the same position as in FIG. 3 of the first embodiment. The intravascular device 1D of the fourth embodiment differs from the first embodiment in that it does not include the inner coil 30 of the first embodiment, the electrode member 22 and the wire member 10 are spaced apart, and a conductor 80 is included. However, in other respects, it has a similar configuration to the intravascular device 1 of the first embodiment. Therefore, parts that perform the same functions as in the first embodiment described above are denoted by the same reference numerals, and redundant description will be omitted as appropriate.

[0041] The intravascular device 1D of the fourth embodiment includes a wire member 10, an electrode member 22, a tubular member 41, and a conductive wire 80. The wire member 10 of the fourth embodiment is similar to the wire member 10 of the first embodiment except that it is not in direct contact (welded) with the electrode member 22 and is disposed at a distance from the electrode member 22.

[0042] The electrode member 22 is disposed at a distance from the wire member 10. The electrode member 22 has a generally cylindrical shape with a spherical tip. The electrode member 22 can be made of the same material as the electrode member 20 of the first embodiment, such as an alloy of Pt (platinum) and W (tungsten).

[0043] The tubular member 41 is a resin member provided around the wire member 10, and its tip is inserted into the electrode member 22 to be connected to the electrode member 22. For example, an adhesive can be used to connect the tubular member 41 and the electrode member 22. The tubular member 41 can be made of the same material as the tubular member 40 of the first embodiment.

[0044] The conductor 80 is a conductor that electrically connects the wire member 10 and the electrode member 22. In this embodiment, a stranded wire (stranded wire member) formed by twisting multiple nickel-titanium wires is used. The conductor 80 is not limited to nickel-titanium, but may be made of, for example, stainless steel. The conductor 80 is not limited to a stranded wire, but may be straight, or may be a coil-shaped, rod-shaped, or plate-shaped conductor. While FIG. 6 shows the conductor 80 connected at the conical surface portion 10c of the wire member 10, it may also be connected near the tip of the wire member 10 (near the first end 1a) with as short a physical distance as possible to further reduce electrical resistance. In this embodiment, the conductor 80 and the tubular member 41 function as a step reducer.

[0045] According to the fourth embodiment, the wire member 10 and the electrode member 22 are not fixed to each other, so that the tubular member 41 can be flexibly deformed, thereby reducing the risk of perforation.

[0046] (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.

[0047] (1) In the first embodiment, an example was given in which the inner coil 30, which is a coil-shaped coil wound in a spiral shape at a regular equal pitch, is arranged as a part of the step reduction portion. However, the present invention is not limited to this. For example, a stranded wire may be arranged along the wire member 10 or wound around the wire member 10 and arranged as a part of the step reduction portion.

[0048] (2) In each embodiment, the electrode member 20 (or electrode member 21) is disposed at the very end of the first end 1a. However, the present invention is not limited to this. For example, the electrode member may be disposed at a position away from the very end of the first end 1a, i.e., at a position closer to the second end 1b than the first end 1a. Furthermore, the number of electrode members is not limited to one, and multiple electrode members may be provided.

[0049] (3) In the first embodiment, an example was described in which the inner coil 30 and the tubular member 40 were provided as the step reduction portion. However, this is not limiting, and the step reduction portion may be formed, for example, by a stranded wire member and a tubular member. The stranded wire member may have a form similar to the conductor 80 shown in the fourth embodiment, or may be a braided stranded wire member formed into a tubular shape. Furthermore, the stranded wire member may be disposed around the wire member, wrapped around it, or disposed along it.

[0050] 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.

[0051] DESCRIPTION OF SYMBOLS 1, 1B, 1C Intravascular device 1a First end 1b Second end 10 Wire member (linear delivery member) 10a Small diameter portion 10b Large diameter portion 10c Conical surface portion 20 Electrode member 20a Tip region 21 Electrode member 30 Inner coil (coil-shaped member, step reduction portion) 40 Tubular member (step reduction portion) 50 Tip portion 60 Connection portion 70 Second tubular member (step reduction portion)

Claims

1. An intravascular device having a first end positioned inside a biological blood vessel and comprising an electrode on the first end side for detecting or stimulating the activity of nerve tissue located outside the blood vessel, A conductive linear delivery member, At least one electrode member provided on the first end side and electrically connected to the linear delivery member, At least a portion of the first step reduction section is positioned between the electrode member and the linear delivery member to reduce the step difference caused by the difference in outer diameter between the outer diameter of the electrode member and the outer diameter of the linear delivery member, A second step reduction section is positioned outside the first step reduction section, adjacent to the first step reduction section, Equipped with, The electrode member is electrically connected to the linear delivery member at the first end of the electrode member. The surface of the electrode member and the surface of the second step reduction portion are substantially flush. An intravascular device in which the electrical resistance between the electrode member and the second end of the linear delivery member opposite to the first end is 100 Ω or less.

2. In the intravascular device according to claim 1, An intravascular device wherein the first step reduction section and the second step reduction section each include at least one of a coil-shaped member provided around the linear delivery member, a twisted wire-shaped member provided around or along the linear delivery member, and a resin tubular member provided around the linear delivery member.

3. In the intravascular device according to claim 2, An intravascular device in which at least a portion of the coil-shaped member is inserted into the electrode member.

4. In the intravascular device according to claim 2 or claim 3, An intravascular device in which at least a portion of the tubular member is externally fitted onto the coil-shaped member.

5. In the intravascular device according to claim 1, An intravascular device in which the electrode member and the linear delivery member are spaced apart, and the electrode member and the linear delivery member are electrically connected by a conductor.

6. In the intravascular device according to claim 5, The conductor is a coil or stranded wire in an intravascular device.

7. In an intravascular device according to any one of claims 1 to 3, The electrode member is an intravascular device in which a metal wire is wound in a spiral shape.

8. In an intravascular device according to any one of claims 1 to 3, An intravascular device in which the electrode member and the linear delivery member are welded together.

9. In an intravascular device according to any one of claims 1 to 3, The aforementioned intravascular device is an intravascular device that is left in a blood vessel for more than one day.

10. In an intravascular device according to any one of claims 1 to 3, The blood vessel in which the intravascular device is placed is a cerebral vein.