JP2016202555A - Stent and treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stent and treatment method capable of continuously increasing a blood flow to the renal artery.SOLUTION: A stent 10 includes: a cylindrical stent base 20 composed of a linear component and having a gap as a whole; and a membrane body 40 for closing a partial gap in the circumferential direction of the stent base 20, where a closure part 12 in which the membrane body 40 is disposed so as to close the gap of the stent base 20, and an exposure part 13 in which no membrane body 40 is disposed so as to expose the gap of the stent base 20 are disposed in the circumferential direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a stent disposed in a blood vessel and a treatment method using the stent.

  The kidney plays important roles such as filtering blood to discharge waste products, regulating blood pressure, secreting hematopoietic hormones, and activating vitamin D related to calcium metabolism.

  When the kidney function decreases, symptoms such as difficulty in discharging waste products from the body occur, and dialysis may be necessary in some cases.

  For this reason, various methods for treating a kidney with reduced function have been proposed. For example, Patent Document 1 describes a method of guiding a drug and a blood flow to a renal artery using a device that is percutaneously inserted into the descending aorta.

US Patent Application Publication No. 2006/0030814

  Since the device described in Patent Document 1 is a device that is percutaneously inserted into the descending aorta, it is temporarily attached and cannot continuously guide blood flow to the renal artery.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a stent and a treatment method capable of continuously increasing blood flow to the renal artery.

  A stent that achieves the above object is a stent having a cylindrical stent base that is formed of linear components and has a gap as a whole, and a membrane that closes a gap in the circumferential direction of the stent base. The stent base body has a closed portion in which the membrane body is disposed and the gap of the stent base body is closed, and an exposed portion in which the gap of the stent base body is exposed without the membrane body being disposed in the circumferential direction. Arranged side by side.

  In the stent configured as described above, a part where the closed part and the exposed part are provided is partially placed in the renal artery so as to be located in the descending aorta, and the exposed part is disposed on the upstream side of the descending aorta and the closed part. Can be arranged downstream. Thereby, the blood flow that flows through the descending aorta and passes through the exposed portion can be guided into the renal artery by the closed portion provided with the membrane body, and the blood flow volume to the renal artery can be continuously increased.

  If the closed part and the exposed part are located on one end side in the axial direction of the stent, one end side where the closed part and the exposed part of the stent are provided projects from one of the right and left renal arteries to the descending aorta. By arranging so that the blood flow flowing through the descending aorta can be guided into the renal artery by the closed portion. The stent can be selectively placed in the left and right renal arteries, and placement is easy.

  If the closed part and the exposed part are located in the central part of the stent in the axial direction, one end side is inserted into one renal artery and the other end side is inserted into the other renal artery, The central portion where the exposed portion is provided can be placed in the descending aorta, and blood flow flowing through the descending aorta can be simultaneously guided into both the right and left renal arteries with one stent.

  If the stent has an X-ray contrast marker at a position corresponding to the closed part or the exposed part, the closed part and the exposed part can be separately observed under X-ray fluoroscopy, and the closed part and the exposed part can be observed in the descending aorta. It becomes easy to arrange in an appropriate position.

  If the stent substrate and the film body are formed of a biodegradable material, the stent can be decomposed and eliminated over time.

  The treatment method for achieving the above object is to provide a blood flow that flows into the lower limb artery and the renal artery by placing a stent having a cylindrical stent base composed of linear components and having a gap as a whole in the descending aorta or renal artery. This is a treatment method for increasing the blood flow rate to the renal artery by changing the ratio of the above to the membranous body. In this treatment method, by placing the stent in the descending aorta or renal artery, the blood flow to the renal artery can be increased, and the blood flow to the renal artery can be continuously increased.

  In the treatment method, the stent having a membrane disposed on the stent substrate is placed in the descending aorta or the renal artery, and the ratio of blood flow flowing to the lower limb artery and the renal artery is changed by the membrane to change the renal artery. If the blood flow volume to the blood vessel is increased, the blood flow volume to the renal artery can be increased by the membrane body, and the blood flow volume to the renal artery can be increased continuously.

  In the treatment method, the stent in which the membrane body closes a part of the stent base in the circumferential direction is partially placed in the renal artery so that the membrane body is located downstream in the descending aorta, and the membrane If the blood flow through the descending aorta is guided by the body into the renal artery to increase the blood flow to the renal artery, the stent is placed in the renal artery, so that the blood flowing through the descending aorta can Can be effectively guided into the artery.

  The stent in which the cross-sectional area of the flow path of the lumen of the stent is partially reduced by the membrane body, the descending aorta so that at least a part of the stent is located downstream from the renal artery entrance of the descending aorta If the stent is placed in the descending aorta, the blood flowing through the descending aorta can be effectively transferred into the renal artery by reducing the blood flow to the lower limb artery and increasing the blood flow to the renal artery. Can be guided to.

It is a top view showing the stent concerning a 1st embodiment. It is sectional drawing which follows the AA line of FIG. It is a top view which shows the indwelling device for indwelling the stent which concerns on 1st Embodiment in the blood vessel. It is sectional drawing which shows the distal part of the device for indwelling. It is a schematic sectional drawing which shows the state which discharge | released the stent from the device for indwelling. It is a schematic sectional drawing which shows the state which indwelled the stent which concerns on 1st Embodiment in the renal artery. It is a top view which shows the stent which concerns on 2nd Embodiment. It is sectional drawing which follows the BB line of FIG. It is sectional drawing which shows the indwelling device for indwelling the stent which concerns on 2nd Embodiment in the blood vessel. It is sectional drawing which follows the CC line of FIG. It is a schematic sectional drawing which shows the state at the time of indwelling the stent which concerns on 2nd Embodiment in a renal artery by the device for indwelling. It is a schematic sectional drawing which shows the state which indwelled the stent which concerns on 2nd Embodiment in the renal artery. It is a top view which shows the stent which concerns on 3rd Embodiment. It is a schematic sectional drawing which shows the state which indwelled the stent which concerns on 3rd Embodiment to the descending aorta. It is a schematic sectional drawing which shows the state which indwelled in the descending aorta with the 1st modification of the stent which concerns on 3rd Embodiment. It is a schematic sectional drawing which shows the state which indwelled in the descending aorta with the 2nd modification of the stent which concerns on 3rd Embodiment.

Embodiments of the present invention will be described below with reference to the drawings. In addition, the dimension ratio of drawing is exaggerated on account of description, and may differ from an actual ratio. In this specification, the side of the device that is inserted into the blood vessel is referred to as the “distal side”, and the proximal side that is operated is referred to as the “proximal side”.
<First Embodiment>

  The stent 10 according to the first embodiment of the present invention is a self-expanding stent that is placed in a renal artery to increase blood flow to the renal artery.

  As shown in FIGS. 1 and 2, the stent 10 partially includes a cylindrical stent base body 20 having a gap as a whole formed by linear components, an X-ray contrast marker 30, and a gap between the stent base body 20. And a film body 40 to be closed.

  The stent base body 20 has a plurality of struts 21 (linear constituent elements) formed in an annular shape while the wire is folded back in a wave shape, and has a gap as a whole by connecting the adjacent struts 21 to each other. It is configured in a cylindrical shape.

  The film body 40 is fixed to the outer peripheral surface of the stent base 20 and can be flexibly expanded as the stent base 20 is deformed. The film body 40 includes a first film portion 41 that covers the entire axial end of the stent substrate 20 in the entire circumference, and a second film portion 42 that partially covers the axial other end of the stent substrate 20 in the circumferential direction. And. The first film part 41 and the second film part 42 are integrally formed. The range in which the second membrane portion 42 covers the stent base body 20 in the circumferential direction is not particularly limited, but is preferably close to 180 degrees in order to enhance the effect of guiding blood into the renal artery.

  The stent 10 includes the contact portion 11 in which the stent base 20 is covered with the first membrane portion 41, the closed portion 12 in which the stent base 20 is covered with the second membrane portion 42, and the stent. The base body 20 includes an exposed portion 13 that is exposed without being covered with the film body 40. The contact portion 11 is a portion that is inserted into the renal artery R and contacts the renal artery R, and the closed portion 12 and the exposed portion 13 are portions that protrude from the renal artery R into the descending aorta D (see FIG. 6). reference).

  For example, the X-ray contrast marker 30 is disposed only at a position corresponding to the exposed portion 13 in the axial end portion of the stent substrate 20. Thereby, the position of the exposed part 13 can be confirmed by X-ray fluoroscopy. Note that the X-ray contrast marker 30 may be disposed at a position corresponding to the closed portion 12 or a position corresponding to the contact portion 11.

  The stent 10 can be expanded from a state in which the diameter is reduced toward the central axis so that the diameter is increased by its own elastic force while the folded portion of each strut 21 is deployed.

  The stent substrate 20 is not limited to the above-described configuration, and a known one such as a mesh shape can be used. And it is preferable that the stent base | substrate 20 is integrally formed in the substantially cylindrical shape with the superelastic metal which shows superelasticity before and after insertion in the living body.

  As the superelastic metal, a superelastic alloy is preferably used. The superelastic alloy here is generally called a shape memory alloy, and exhibits superelasticity at least at a living body temperature (around 37 ° C.). Preferably, a TiNi alloy of 49 to 54 atomic% Ni, a Cu—Zn alloy of 38.5 to 41.5 wt% Zn, and a Cu—Zn—X alloy of 1 to 10 wt% X (X = Be, Si, Sn) , Al, Ga), and a superelastic alloy such as a Ni-Al alloy of 36-38 atomic% Al is used. The TiNi alloy is particularly preferable. Further, a Ti—Ni—X alloy (X = Co, Fe, Mn, Cr, V, Al, Nb, W, B, in which a part of the Ti—Ni alloy is substituted with 0.01 to 10.0 wt% X, Au, Pd, etc.) or a Ti—Ni—X alloy (X = Cu, Pb, Zr) in which a part of the Ti—Ni alloy is substituted by 0.01 to 30.0 atomic%, By selecting the cold working rate or / and the final heat treatment conditions, the mechanical properties can be appropriately changed.

The buckling strength (yield stress during loading) of the superelastic alloy used is 5 to 200 kg / mm ² (22 ° C.), preferably 8 to 150 kg / mm ^2. Restoring stress (yield during unloading) The stress is 3 to 180 kg / mm ² (22 ° C.), preferably 5 to 130 kg / mm ² . Superelasticity here means that even if it is deformed (bending, pulling, compressing) to the region where ordinary metal plastically deforms at the operating temperature, it will recover to its original shape without requiring heating after releasing the load. Means that.

  And the stent base | substrate 20 is produced by removing a strut non-component part, for example using a super elastic alloy pipe, and, thereby, is an integral formation. The formation of the stent substrate 20 by the superelastic alloy pipe can be performed by cutting (for example, mechanical polishing, laser cutting), electric discharge machining, chemical etching, or the like, and may be performed by using them together.

  The constituent material of the film body 40 is preferably a material that can be expanded and contracted flexibly. For example, natural rubber, silicone rubber, nitrile rubber, fluorine rubber, and the like can be suitably used.

  As a constituent material of the X-ray contrast marker 30, for example, gold, platinum, platinum-iridium alloy, silver, stainless steel, molybdenum, tungsten, tantalum, palladium, or an alloy thereof can be preferably used.

  Next, an indwelling device 50 for placing the stent 10 in the renal artery R will be described. As shown in FIGS. 3 and 4, the indwelling device 50 includes a tubular sheath 60 that houses the stent 10, and an inner tube 70 that includes a stent pushing portion 71 that can push the stent 10 in the distal direction. .

  The sheath 60 is open on the distal side and the proximal side, and a receiving portion 61 capable of accommodating the stent 10 is provided inside the distal side. The distal opening functions as an outlet of the stent 10 when the stent 10 is placed at a target site. The stent 10 is housed in the housing portion 61 in a state of being reduced in diameter. When the stent 10 is released from the distal opening, the stress load of the stent 10 is released, and the stent 10 expands by its own elastic force, and is restored to the shape before compression.

  A sheath hub 62 is fixed to the proximal portion of the sheath 60. Inside the sheath hub 62, a valve body (not shown) that holds the inner tube 70 in a slidable and liquid-tight manner is provided.

  The inner tube 70 includes a shaft-like inner tube main body 72, a distal portion of the inner tube main body 72, an inner tube distal portion 73 protruding from the distal end of the sheath 60, and the inner tube main body 72. And an inner tube hub 74 fixed to the proximal portion.

  The inner tube distal portion 73 protrudes from the distal portion of the sheath 60 and is formed in a tapered shape that gradually decreases in diameter toward the distal portion. By forming in this way, insertion into a blood vessel becomes easy. Further, the inner tube distal portion 73 has a proximal side capable of contacting the distal portion of the sheath 60 and functions as a stopper that prevents the sheath 60 from moving in the distal direction.

  A stent holding portion 75 is provided on the proximal side of the inner tube distal portion 73 of the inner tube 70. A stent pusher 71 is provided on the proximal side of the stent holder 75 by a predetermined distance. The stent holding part 75 and the stent extruding part 71 have X-ray contrast properties. The stent 10 is disposed between the two stent holding portions 75 and the stent push-out portion 71. The outer diameters of the stent holding portion 75 and the stent push-out portion 71 are large enough to contact the compressed stent 10. For this reason, the movement of the stent 10 to the distal side is restricted by the stent holding portion 75, and the movement to the proximal side is restricted by the stent push-out portion 71. Then, as shown in FIG. 5, when the sheath 60 is moved to the proximal side while the position of the inner tube 70 is maintained, the movement of the stent 10 to the proximal side is regulated by the stent pusher 71, and the stent 10 Slides on the inner surface of the sheath 60 and is released from the sheath 60 to expand.

  The inner tube 70 penetrates through the sheath 60 and protrudes from the proximal opening of the sheath 60. An inner tube hub 74 is fixed to the proximal portion of the inner tube 70. The inner tube 70 is formed such that a lumen 76 through which the guide wire is inserted extends from the distal portion to the proximal portion.

  Next, a method for placing the stent 10 according to the first embodiment in the renal artery R will be described.

  First, an indwelling device 50 in which the stent 10 whose diameter is reduced toward the central axis is accommodated in the accommodating portion 61 of the sheath 60 is prepared, and the inside of the sheath 60 and the inside of the inner tube 70 are filled with physiological saline.

  Next, an introducer sheath (not shown) is placed in the patient's blood vessel by, for example, the Seldinger method, and the guide wire and the placement device 50 are placed in a state where the guide wire is inserted into the lumen 76 of the placement device 50. Insert into the blood vessel from inside the introducer sheath. Subsequently, the indwelling device 50 is pushed forward with the guide wire advanced, and the distal portion of the sheath 60 is inserted from the descending aorta D into the renal artery R.

  Next, the position of the X-ray contrast marker 30 of the stent holding part 75, the stent pushing part 71 and the stent 10 is confirmed under X-ray fluoroscopy, the contact part 11 is in the renal artery R, and the exposed part 13 is in the descending aorta D. The position of the indwelling device 50 is adjusted so that the closing portion 12 is located on the downstream side of the descending aorta D on the upstream side. Since the X-ray contrast marker 30 is provided on one of the exposed portion 13 or the closed portion 12 (the exposed portion 13 in this embodiment), the exposed portion 13 and the closed portion 12 can be distinguished and observed under fluoroscopy, Each can be placed in an appropriate position.

  Thereafter, as shown in FIG. 5, the sheath hub 62 is pulled and moved proximally while the inner tube hub 74 is held by hand to hold the stent pushing portion 71 from moving proximally. The stent 10 is released from the distal opening of the sheath 60 moving in the direction to be pushed out by the stent pusher 71. Thereby, the stent 10 is released from the stress load, expands by its own elastic force, and is restored to the shape before compression. Then, as shown in FIG. 6, the contact portion 11 expands in the renal artery R and is held in contact with the renal artery R, the exposed portion 13 is the upstream side in the descending aorta D, and the closing portion 12 is the descending aorta D. Located on the downstream side. If necessary, the stent 10 can be placed in another renal artery R by the same method.

  After the stent 10 is placed in the renal artery R, the guide wire and the placement device 50 are removed from the blood vessel via the introducer sheath, and the introducer sheath is removed, and the procedure is completed.

  Next, the operation of the stent 10 according to the first embodiment will be described.

  When the stent 10 is placed in the renal artery R, the contact portion 11 of the stent 10 comes into contact with the renal artery R and is held in the renal artery R by the expansion force of the stent base 20. The exposed portion 13 protruding from the renal artery R into the descending aorta D is located on the upstream side in the descending aorta D, and the closing portion 12 is located on the downstream side in the descending aorta D. For this reason, blood flowing through the descending aorta D and passing through the gap of the exposed portion 13 strikes the closed portion 12 and is guided into the renal artery R. In this way, the amount of blood flowing to the downstream side of the descending aorta, that is, the lower limb artery can be decreased, and the amount of blood flowing into the renal artery R can be increased accordingly. Thereby, the amount of blood reaching the kidney increases, and the function of the kidney can be improved.

  As described above, the stent 10 according to the first embodiment includes the tubular stent base 20 that is configured by linear components and has a gap as a whole, and a membrane that blocks a part of the gap in the circumferential direction of the stent base 20. A closed body 12 in which the membrane body 40 is disposed and the gap of the stent base body 20 is blocked, and an exposed portion in which the gap of the stent base body 20 is exposed without the membrane body 40 being disposed. 13 are arranged side by side in the circumferential direction. The stent 10 thus configured is partially placed in the renal artery R so that the site where the closing portion 12 and the exposed portion 13 are provided is located in the descending aorta D, and the exposed portion 13 is upstream of the descending aorta D. The closing part 12 can be arranged on the downstream side as well as on the side. As a result, the blood flow flowing in the descending aorta D and passing through the exposed portion 13 can be guided into the renal artery R by the closed portion 12 provided with the membrane body 40, and the blood volume to the renal artery R is continuously increased. Thus, the kidney function can be continuously increased.

  Moreover, since the closing part 12 and the exposed part 13 are located in the one end side of the axial direction of the stent 10, the one end side in which the closing part 12 and the exposed part 13 of the stent 10 are provided from one renal artery R of right and left. It can be arranged to project into the descending aorta D. Thereby, the blood flowing through the descending aorta D and passing through the exposed portion 13 can be guided into the renal artery R by the closed portion 12. Then, the stent 10 can be selectively placed in each renal artery R, and placement is easy.

  Further, since the stent 10 has the X-ray contrast marker 30 at a position corresponding to the exposed portion 13, the closed portion 12 and the exposed portion 13 can be distinguished and observed under fluoroscopy, and the closed portion 12 and the exposed portion 13 are descended. It becomes easy to arrange in the appropriate position in the aorta D, that is, the position where the closed portion 12 is on the downstream side and the exposed portion 13 is on the upstream side.

  The present invention also includes a treatment (therapy) method. In this treatment method, a stent having a cylindrical stent base composed of linear components and having a gap as a whole is placed in the renal artery and the ratio of blood flow flowing to the lower limb artery and the renal artery is changed. A treatment method for increasing blood flow to an artery. In this treatment method, by placing the stent in the renal artery, the blood flow to the renal artery can be increased by the stent, and the blood flow to the renal artery can be increased continuously.

  In the treatment method, the stent having a membrane disposed on the stent substrate is placed in the renal artery, and the ratio of blood flow flowing to the lower limb artery and the renal artery is changed by the membrane to change blood to the renal artery. The flow rate can be increased. In this way, the blood flow to the renal artery can be increased by the membrane provided on the stent, and the blood flow to the renal artery can be increased continuously.

In the above treatment method, the stent in which the membrane body blocks a part of the stent base in the circumferential direction is placed in the renal artery so that the membrane body is located downstream in the descending aorta, and descends by the membrane body. The blood flow through the aorta can be guided into the renal artery to increase the blood flow to the renal artery. In this way, by partially placing the stent in the renal artery, the blood flow flowing through the descending aorta can be effectively guided into the renal artery by the membrane.
Second Embodiment

  The stent 100 according to the second embodiment is a self-expanding stent that is placed in both the right and left renal arteries.

  As shown in FIGS. 7 and 8, the stent 100 includes a cylindrical stent base 110 that is formed of linear components and has a gap as a whole, and a membrane body 120 that partially closes the gap of the stent base 110. ing. The stent base 110 is a tube having a plurality of struts 111 (linear constituent elements) formed in a ring shape while the wire is folded back in a wave shape, and having a gap as a whole by connecting adjacent struts 111 adjacent to each other. Configured in shape.

  The film body 120 can be expanded flexibly as the stent base 110 is deformed, and is fixed to the outer peripheral surface of the stent base 110. The membrane 120 includes a first membrane 121 that covers the entire circumference of one end of the stent substrate 110 in the axial direction, and a second membrane that covers a portion of the stent substrate 110 in the circumferential direction adjacent to the first membrane 121. 122, a third membrane portion 123 covering the entire circumference of the stent substrate 110 on the other end side in the axial direction, and a fourth membrane portion 124 covering the circumferential portion of the stent substrate 110 adjacent to the third membrane portion 123. And. The range in which the second film part 122 and the fourth film part 124 cover the stent substrate 110 in the circumferential direction is not particularly limited, but is preferably close to 180 degrees. It is preferable that the circumferential positions where the second film part 122 and the fourth film part 124 are arranged with respect to the stent substrate 110 coincide with each other.

  The stent 100 includes a first contact portion 101 in which the stent base 110 is covered with the first membrane portion 121 and a second contact portion in which the stent base 110 is covered with the second membrane portion 122 by the stent base 110 and the membrane body 120 described above. 102, the first closing portion 103 in which the stent base 110 is covered with the third membrane portion 123, the second closing portion 104 in which the stent base 110 is covered with the fourth membrane portion 124, and the stent base 110 covered with the membrane body 120. And an exposed portion 105 exposed without breaking. The exposed portion 105 includes a first exposed portion 106 located on the same circumference as the first closed portion 103, a second exposed portion 107 located on the same circumference as the second closed portion 104, the first exposed portion 106, and the first exposed portion 106. And a third exposed portion 108 that is not covered by the film body 120 around the entire circumference between the two exposed portions 107.

  The first contact portion 101 and the second contact portion 102 are portions that are inserted into different renal arteries R on the left and right sides and come into contact with the renal arteries R. The first closing portion 103, the second closing portion 104, and the first exposed portion. 106, the second exposed portion 107, and the third exposed portion 108 are portions disposed in the descending aorta D.

  The stent 100 can be expanded from a state in which the diameter is reduced toward the central axis so that the diameter is increased by its own elastic force while the folded portion of each strut 111 is deployed.

  Next, an indwelling device 130 for placing the stent 100 in the renal artery R will be described. As shown in FIGS. 9 and 10, the indwelling device 130 includes a tubular sheath 140 that accommodates the stent 100, an outer tube 150 that can accommodate the sheath 140, and a stent 140 that is disposed inside the sheath 140 and distally disposes the stent 100. A stent pusher 160 that can be extruded in the direction.

  The outer tube 150 is formed with a first lumen 151 that can accommodate the sheath 140 and a second lumen 152 into which a guide wire can be inserted.

  The sheath 140 includes a branch portion 141 that is divided into two branches on the distal side of the tubular body, and a slit-like opening 142 is formed on the side closer to each branch portion 141. The cross section of each branch part 141 is C-shaped by forming an opening 142 on the side close to each other. Inside the branch portion 141, the stent 100 which is contracted toward the central axis and is bent at the third exposed portion 108 is accommodated so that each end portion is disposed at the opposite branch portion 141. The stent 100 is bent so that the first closing portion 103 and the second closing portion 104 are outside. The sheath 140 protrudes from the outer tube 150 in the distal direction, so that the two branch portions 141 are curved and protrude in a direction away from each other by their own elastic force (see FIG. 11).

  The stent extruding portion 160 is a long member disposed inside the sheath 140. The distal portion of the stent pusher 160 can contact the outer surface of the stent 100 disposed within the sheath 140.

  Next, a method for placing the stent 100 according to the second embodiment in the renal artery will be described.

  First, an indwelling device 130 in which the stent 100 is accommodated in the sheath 140 is prepared, and the inside of the sheath 140 and the inside of the outer tube 150 are filled with physiological saline.

  Next, an introducer sheath (not shown) is placed in the patient's blood vessel by, for example, the Seldinger method, and the guide wire and the placement device 130 are placed in the introducer sheath while the guide wire is inserted into the second lumen 152. Insert into the blood vessel from inside. Subsequently, the indwelling device 130 is pushed forward while the guide wire W is advanced, and the distal portion of the sheath 140 is positioned downstream of the entrance portion O of the renal artery R in the descending aorta D.

  Next, as shown in FIG. 11, the sheath 140 is moved in the distal direction with the outer tube 150 fixed, and the two branch portions 141 are inserted into the left and right renal arteries R while being bent by their own elastic force. To do. Next, the sheath 140 is moved in the proximal direction in a state where the stent pushing portion 160 is brought into contact with the stent 100 and movement of the stent 100 in the proximal direction is restricted. As a result, the stent 100 is pushed out of the sheath 140 through the slit-shaped opening 142, the stress load is released, and the stent 100 is expanded by its own elastic force, and is restored to the shape before compression. Then, as shown in FIG. 12, the first contact portion 101 and the second contact portion 102 are expanded in the right and left renal arteries R and are held in contact with the renal artery R, and the first exposed portion 106 and the second contact portion 102 are held. The exposed portion 107 is located upstream in the descending aorta D, and the first closing portion 103 and the second closing portion 104 are located downstream in the descending aorta D.

  After the stent 100 is placed in the renal artery R, the guide wire W and the placement device 130 are removed from the blood vessel via the introducer sheath, and the introducer sheath is removed, and the procedure is completed.

  Next, the operation of the stent 100 according to the second embodiment will be described.

  When the stent 100 is placed in the renal artery R, the first contact portion 101 and the second contact portion 102 of the stent 100 come into contact with the left and right renal arteries R and are held in the renal artery R by the expansion force of the stent base 110. The The first exposed portion 106 and the second exposed portion 107 projecting from the renal artery R into the descending aorta D are located upstream in the descending aorta D, and the first closing portion 103 and the second closing portion 104 are Located downstream of the descending aorta D. For this reason, blood flowing through the descending aorta D and passing through the gap between the first exposed portion 106 and the second exposed portion 107 strikes the first closed portion 103 and the second closed portion 104 and is guided into the right and left renal arteries R. For this reason, the blood flow to the lower limb artery can be decreased, and the blood flow flowing into the renal artery R can be increased accordingly. Thereby, the amount of blood reaching the kidney increases, and the function of the kidney can be continuously improved.

As described above, in the stent 100 according to the second embodiment, since the first closing portion 103 and the second closing portion 104 are located in the central portion in the axial direction of the stent 100, one end side is set to one renal artery R. The other end side is inserted into the other renal artery R, and the central portion where the first closing portion 103, the second closing portion 104, and the exposed portion 105 are provided can be disposed in the descending aorta D. For this reason, the blood flow flowing through the descending aorta D can be simultaneously guided into the right and left renal arteries R by one stent 100. In addition, since the stent 100 is inserted into the right and left renal arteries R, the stent 100 is stably held, and misalignment or the like hardly occurs.
<Third Embodiment>

  The stent 170 according to the third embodiment is a self-expanding stent that is placed downstream of the entrance portion O of the renal artery R in the descending aorta D.

  As shown in FIG. 13, the stent 170 includes a cylindrical stent base 180 that is formed of linear components and has a gap as a whole, and a membrane body 190 that closes the gap of the stent base 180. The stent base 180 is a tube having a plurality of struts 191 (linear constituent elements) formed in an annular shape while the wire is folded back in a wave shape, and having a gap as a whole by connecting the adjacent struts 191 to each other. Configured in shape. The stent 170 is provided with contact portions 171 at both ends in the axial direction, and a small-diameter portion 172 having an inner diameter and an outer diameter smaller than the contact portion 171 is formed in the central portion in the axial direction.

  The film body 190 is fixed to the entire outer peripheral surface of the stent base 180 and can be flexibly expanded as the stent base 180 is deformed.

  The stent 170 can be expanded from a state where the diameter is reduced toward the central axis so that the diameter is increased by its own elastic force while the folded portion of each strut 191 is deployed.

  The stent 170 according to the third embodiment is placed downstream from the entrance portion O of the renal artery R in the descending aorta D by the placement device 50 (see FIG. 3) described in the first embodiment.

  Next, the operation of the stent 170 according to the third embodiment will be described.

When the stent 170 is cut location, the contact portions 171 of the stent 170 than the inlet portion O of the renal arteries R in the descending aorta D contacts the downstream side and is retained in the descending aorta D by expansion force of the stent body 180 . The flow path inside the stent 170 has a reduced cross-sectional area at the small diameter portion 172. For this reason, as shown in FIG. 14, the blood flowing in the descending aorta D is subjected to resistance by the small diameter portion 172 inside the stent 170. As a result, the blood flow to the lower limb artery is decreased, and the blood flow flowing into the renal artery R can be increased accordingly. Thereby, the amount of blood reaching the kidney increases, and the function of the kidney can be improved.

  As described above, in the treatment (treatment) method according to the third embodiment, the stent in which the cross-sectional area of the flow path in the lumen of the stent is partially reduced by the membrane is used, and at least a part of the stent is the descending aorta. Indwelling in the descending aorta so as to be located downstream of the renal artery entrance, the blood flow to the lower limb arteries is decreased to increase the blood flow to the renal arteries. For this reason, by placing the stent in the descending aorta, the blood flow flowing through the descending aorta can be effectively guided into the renal artery.

  Note that the present invention is not limited to the above-described embodiments, and various modifications can be made by those skilled in the art within the technical idea of the present invention. For example, the stent substrate and the membrane body may be formed of a biodegradable material. In this way, the stent can be disassembled and lost over time. The biodegradable material is preferably, for example, a biodegradable metal material or a biodegradable polymer material. As the biodegradable metal material, for example, magnesium can be preferably used. Biodegradable polymer materials include, for example, biodegradable synthetic polymer materials such as polylactic acid, polyglycolic acid, lactic acid-glycolic acid copolymer, polycaprolactone, lactic acid-caprolactone copolymer, poly-γ-glutamic acid, Alternatively, biodegradable natural polymer materials such as cellulose and collagen can be suitably used.

  Further, as in the first modification of the third embodiment shown in FIG. 15, a contact portion 201 that contacts the descending aorta D is provided on one end side of the stent 200, and the inner diameter and the contact portion 201 are set on the other end side. A small-diameter portion 202 whose outer diameter decreases may be provided. The stent 200 includes a stent base body 203 and a film body 204 that covers the stent base body 203. Even with such a configuration, the blood flow rate to the descending aorta D can be decreased and the blood flow rate to the renal artery R can be increased.

  In addition, as in the second modification of the third embodiment shown in FIG. 16, the inner member 212 (membrane body) in which the stent 210 decreases inside and outside the contact portion 211 that contacts the descending aorta D. May be arranged. The contact portion 211 includes a stent base 213 and a film body 214 that covers the stent base 213. The inner member 212 is formed of the same material as the film body 214, for example. Even with such a configuration, the blood flow to the lower limb artery can be decreased and the blood flow to the renal artery R can be increased.

  Also, the membrane body may be placed inside rather than outside the stent substrate, or may be placed on both the inside and outside.

  Further, in the contact portion that contacts the renal artery R or descending aorta D of the stent, the stent substrate may not be covered with the membrane. Further, the stent may not be self-expanding, and may be configured to be expanded by plastic deformation with a balloon. In the second embodiment, the third exposed portion 108 in which the film body 120 is not provided at all in the circumferential direction may not necessarily be provided.

  Moreover, the film body may not be configured to completely block the flow of fluid, and may have, for example, some fluid flowability (permeability).

10, 100, 170, 200, 210 stent,
11, 171, 201, 211 contact part,
12 closure,
13, 105 Exposed part,
20, 110, 180, 203, 213 stent substrate,
30 X-ray contrast markers,
40, 120, 190, 204, 214 Membrane,
101 1st contact part (contact part),
102 2nd contact part (contact part),
103 1st closing part (closing part),
104 second closing part (closing part),
106 first exposed portion,
107 second exposed portion,
108 third exposed portion,
212 inner member (film body),
D descending aorta,
O opening,
R Renal artery.

Claims (9)

A cylindrical stent base composed of linear components and having a gap as a whole;
A membrane body that closes a gap in the circumferential direction of the stent substrate,
A stent in which a closed portion where the membrane body is disposed and the gap of the stent base is closed, and an exposed portion where the membrane body is not disposed and the gap of the stent base is exposed are arranged side by side in the circumferential direction.   The stent according to claim 1, wherein the closing portion and the exposed portion are located on one end side in the axial direction of the stent.   The stent according to claim 1, wherein the closing portion and the exposed portion are located in a central portion in the axial direction of the stent.   The stent according to any one of claims 1 to 3, further comprising an X-ray contrast marker at a position corresponding to the closed portion or the exposed portion.   The stent according to any one of claims 1 to 4, wherein the stent substrate and the film body are formed of a biodegradable material.   A stent having a cylindrical stent base composed of linear components and having a gap as a whole is placed in the descending aorta or renal artery, and the ratio of blood flow flowing to the lower limb artery and renal artery is changed by the membrane body. A method of increasing blood flow to the renal artery.   The stent having a membrane disposed on the stent substrate is placed in the descending aorta or the renal artery, and the ratio of the blood flow flowing to the lower limb artery and the renal artery is changed by the membrane body to thereby change the blood flow to the renal artery. The treatment method according to claim 6, which is increased.   The stent in which the membranous body blocks part of the stent substrate in the circumferential direction is placed in the renal artery so that the membranous body is located downstream in the descending aorta, and the blood flow through the descending aorta by the membranous body The treatment method according to claim 7, wherein blood flow into the renal artery is increased by guiding the blood flow into the renal artery.   The stent in which the cross-sectional area of the flow path of the lumen of the stent is partially reduced by the membrane body, the descending aorta so that at least a part of the stent is located downstream from the renal artery entrance of the descending aorta The treatment method according to claim 7, wherein the blood flow to the renal artery is increased by decreasing the blood flow to the lower limb artery.

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