JP2013135794A - Flow diverter stent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flow diverter stent capable of preventing blood from flowing out to a cerebral aneurysm and being held at a proper position for a long period of time.SOLUTION: The flow diverter stent 1A includes: a leading end side braid 2A formed of a cylindrical braid; a coil body 3 connected to a base end of the leading end side braid 2A; and a base end side braid 2B formed of a cylindrical braid connected to the base end of the coil body 3.

Description

  The present invention relates to a flow diverter stent that is suitably used in the medical field.

  In recent years, flow diverter stents have been developed in the medical field that suppress blood flow to clot the cerebral aneurysm to treat the cerebral aneurysm. The flow diverter stent is generally composed of a tubular braided body, and is arranged at a site where a cerebral aneurysm is located in an artery, and generally suppresses blood from flowing into the cerebral aneurysm side. Is.

  Moreover, as a thing similar to the structure of said flow diverter stent, the stent which is a well-known technique is mentioned, for example (for example, refer patent documents 1-3). Patent Document 1 discloses a stent configured by a tubular braided body in which an intermediate portion is tightly knitted. Patent Document 2 discloses a ureteral stent composed of a coil body. Furthermore, Patent Document 3 discloses a stent in which both end portions are formed in a flare shape.

US Pat. No. 7763011 US Pat. No. 6,790,223 US Pat. No. 5,064,435

  However, the flow diverter stent having the above configuration is insufficient in rectification of blood passing through the inside thereof, and further performance improvement has been demanded. In addition, even if the configurations disclosed in Patent Documents 1 to 3 are adopted as the configuration of each flow diverter stent, rectification is insufficient, the outflow to the cerebral aneurysm cannot be suppressed, There is a risk that it cannot be held in position.

  Accordingly, in view of the above problems, the present invention reliably rectifies the blood flow while reliably suppressing the flow of blood to the cerebral aneurysm, and further ensures that the flow diverter stent is in an appropriate position in the artery. An object is to provide a flow diverter stent that can be retained.

  The present invention relates to a flow diverter stent that is disposed in an artery and through which blood flows, and includes a distal braid formed of a tubular braid, and a coil positioned at the proximal end of the distal braid A flow diverter stent comprising: a body; and a proximal-side braided body that is located at a proximal end of the coil body and is configured by a tubular braided body.

  The flow diverter stent of the present invention is inserted into an artery and then disposed at a position where the coil body part faces a cerebral aneurysm. Here, the blood flowing in the flow diverter stent passes through the proximal braid, the coil, and the distal braid sequentially from the upstream side (side closer to the heart). Then, a spiral blood flow is generated due to the spiral shape of the coil body. For this reason, the blood flowing in the coil body has a propulsive force in the distal direction, and the blood undergoes a rectifying action in the direction of the distal braid body located in the distal direction of the coil body according to the propulsive force. Become. Therefore, it is possible to suppress the blood in the artery from flowing out toward the cerebral aneurysm. In addition, the distal side braided body and the proximal side braided body arranged at both ends are produced by braiding braided strands, so that a complicated uneven shape is formed on the surface, and the inner peripheral surface of the artery Sufficient friction can be secured. Therefore, the locking force for locking the flow diverter stent in the artery can be improved, and the coil body portion can be held at an appropriate position for a long time.

  Further, in the flow diverter stent, the distal end side braided body and the braided body constituting the proximal end side braided body include a braided strand formed along one direction and a braid formed along the other direction. The coil body is formed along one direction among the braided strands in the braided body constituting the distal end side braided body and the proximal end side braided body. A configuration is proposed in which the braided strand formed along the other direction left after the braided strand is removed is used as a coil strand.

  By adopting such a configuration, the continuity of the strands is ensured between the coil body and the distal end side braided body, and between the coil body and the proximal end side braided body. When the tarstent is curved, distortion is unlikely to occur at the distal end position and the proximal end position of the coil body, and the blood flow rectifying action is not impaired.

  Further, in the flow diverter stent, the coil body may be made of a coil wire that is different from a braided wire that forms a braided body constituting the distal end side braided body and the proximal end side braided body. .

  By adopting such a configuration, it is possible to set the wire material and the wire diameter suitable for each part in the distal end side braided body, the coil body, and the proximal end side braided body.

  In the above flow diverter stent, the coil body may be a multi-strand coil body formed by twisting a plurality of strands.

  Even when the multi-strand coil body is bent in a state of being arranged in an artery, a gap is hardly generated between the strands. For this reason, it is possible to more reliably prevent blood flowing in the coil body from flowing out toward the cerebral aneurysm.

  In the above flow diverter stent, the coil body has a constant coil inner diameter over its entire length, and the distal end portion of the distal end side braid and the proximal end portion of the proximal end braid are each open end surface. It is good also as a structure currently formed in the flare shape which an outer diameter expands as it goes to.

  In this way, when the inner diameter of the coil body is constant, a stable blood flow can be formed, so that the rectification effect of blood flowing in the coil body is greatly improved. Further, when the distal end portion of the distal end side braided body arranged at both ends and the proximal end portion of the proximal end side braided body have the flare shape as described above, the distal end portion of the distal end side braided body, and Since the proximal end portion of the proximal end braid is more strongly adhered to the inner peripheral surface of the artery, there is an advantage that the locking force in the artery is increased.

  Further, in the above flow diverter stent, the coil outer diameter of the distal end of the coil body is smaller than the coil outer diameter of the proximal end of the coil body, and the outer diameter of the proximal end of the distal end side braided body is It is good also as a structure thinner than the outer diameter of the front-end | tip of the said base end side braid.

  By adopting such a configuration, if the blood vessel diameter is thick on the upstream side with respect to the cerebral aneurysm and the downstream side is relatively thinner than that, the flow diverter stent can be reliably secured according to the size of the blood vessel diameter at each position. In addition to being able to be inserted, the outer peripheral surfaces of the distal end side braided body and the proximal end side braided body can be reliably brought into close contact with the inner peripheral surface of the artery and locked at desired positions.

  In the above flow diverter stent, the outer diameter of the coil wire constituting the coil body and the outer diameter of the braided wire forming the distal end side braided body and the proximal end side braided body are the same. It is good also as a certain structure.

  By adopting such a configuration, it is possible to reduce the disturbance of blood flow as much as possible at the boundary between the coil body and the distal end side braid and at the boundary between the coil body and the proximal end side braid. Therefore, it is possible to sufficiently secure the blood flow rectifying effect in the flow diverter stent.

  The flow diverter stent of the present invention can suppress blood from flowing out to a cerebral aneurysm and has an effect of being held at an appropriate position in an artery for a long period of time.

The conceptual diagram which shows the flow diverter stent concerning Example 1 from the side. Conceptual diagram showing the state of use of the flow diverter stent The conceptual diagram which shows the flow diverter stent concerning Example 2 from the side. The conceptual diagram which shows the flow diverter stent concerning Example 3 from the side. The conceptual diagram which shows the flow diverter stent concerning Example 4 from the side.

  Examples 1 to 5 of a flow diverter stent according to the present invention will be described with reference to the accompanying drawings.

Example 1
As conceptually shown in FIG. 1, a flow diverter stent 1A used for medical use is positioned at a distal end braid 2A composed of a tubular braid and a proximal end of the distal braid 2A. A coil body 3 and a proximal-side braid body 2B made of a tubular braid body, which is located at the proximal end of the coil body 3, are provided.

  The distal end side braided body 2A and the proximal end side braided body 2B are formed of a tubular braided body braided by metal braided strands 20A and 20B made of a superelastic alloy such as NiTi. Specifically, the braided body includes a plurality of braided strands 20A formed along one direction and a plurality of braided strands 20B formed along another direction different from the direction of the braided strand 20A. It is constructed by braiding. The outer diameters of the braided bodies 2A and 2B are constant over the entire length.

  The coil body 3 removes the braided strand 20A formed along one direction from the braided strands 20A and 20B of the braid constituting the distal end side braid 2A and the base end braid 2B. The braided wire 20 </ b> B formed along the other direction that is left is configured as a coil wire 30. Thereby, this coil body 3 is formed in the shape of a multi-strand coil body formed by twisting a plurality of coil strands 30 so as to be closely wound. The coil outer diameter of the coil body 3 is substantially equal to the outer diameters of the distal end side braid 2A and the proximal end braid 2B, and the coil inner diameter is constant over the entire length. In forming the coil body 3, as a method for removing the braided strand 20A, various known methods such as a method of burning off by laser irradiation are employed.

  As shown in FIG. 2, the flow diverter stent 1 </ b> A having the above-described configuration is inserted into the artery X and disposed at a position where the coil body 3 faces the cerebral aneurysm Y. Here, blood flowing in the flow diverter stent 1A passes through the proximal braid 2B, the coil body 3, and then the distal braid 2A in order from the upstream side (side closer to the heart). However, a spiral blood flow is generated in the coil body 3 due to the spiral shape of the coil body 3. For this reason, a propulsive force is generated in the blood flowing in the coil body 3 in the distal direction, and the blood undergoes a rectifying action in the direction of the distal braid 2A located in the distal direction of the coil body 3 according to the propulsive force. It will be. Therefore, the blood in the artery X is suppressed from flowing out toward the cerebral aneurysm Y.

  Furthermore, when the inner diameter of the coil body 3 is constant as described above, a stable blood flow can be formed inside the coil body 3, so that the blood rectifying effect in the coil body 3 is greatly improved. Further, although the coil body 3 is formed in a multi-strand coil shape, the distal end side braid body 2A and the braided strand 20A of the proximal end side braid body 2B are removed, so that the distal end The side braid 2A and the proximal end braid 2B are more flexible, and even if the artery X in the vicinity of the cerebral aneurysm Y is complicatedly curved or bent, it can be appropriately arranged.

  Further, since the distal end side braid body 2A and the proximal end side braid body 2B are cylindrical bodies knitted by a plurality of braided strands 20A and 20B, a complicated uneven shape is formed on the surface. Accordingly, the outer peripheral surface of the distal end side braid 2A and the proximal end braid 2B can secure sufficient friction with the inner peripheral surface of the artery X, and the coil body 3 portion is positioned in the axial direction. The shift is suppressed, and the position corresponding to the cerebral aneurysm Y is stably held for a long time.

  In addition, the coil body 3 has a configuration in which the braided strands 20A and 20B in the braids constituting the distal end side braid 2A and the proximal end braid 2B are used as the coil strands 30. The continuity of the wire is ensured between the body 3 and the distal braid 2A and between the coil body 3 and the proximal braid 2B, and the flow diverter stent 1A is curved. When this occurs, distortion is unlikely to occur at the distal end position and the proximal end position of the coil body 3, and the blood flow rectifying action is unlikely to be impaired.

  In the flow diverter stent 1A described above, the outer diameter of the coil wire 30 constituting the coil body 3 and the braid strands 20A and 20B constituting the distal end side braid 2A and the proximal end braid 2B. Since the outer diameters of the coil body 3 and the coil body 3 are the same, the disturbance of the blood flow is minimized as much as possible at the boundary position between the coil body 3 and the distal braid 2A and at the boundary position between the coil body 3 and the proximal braid 2B. can do. Therefore, a sufficient blood flow rectifying effect in the flow diverter stent 1A can be ensured.

  In addition, since the coil body 3 is in the form of a multi-strand coil body, even when the coil body 3 is bent in the artery X, a gap is hardly generated between the coil strands 30. For this reason, it is possible to more reliably prevent blood flowing in the coil body 3 from flowing out toward the cerebral aneurysm Y.

  1 and 2 are conceptual diagrams showing the coil body 3 in an exaggerated manner. However, the coil wire 30 of the coil body 3 and the braiding of the distal end side braid 2A and the proximal end braid 2B are shown. The strands 20A and 20B have the same outer diameter. The same applies to FIGS. 3 to 5 below.

(Example 2)
Hereinafter, the flow diverter stent 1B according to the second embodiment will be described with reference to FIG. 3, but the description common to the first embodiment will be omitted, and the same reference numerals will be given in the drawing.

  As shown in FIG. 3, the coil body 3 of the flow diverter stent 1B has a constant coil inner diameter over its entire length. On the other hand, the distal end portion of the distal end side braid body 22A and the proximal end portion of the proximal end side braid body 22B are formed in a flare shape in which the outer diameter increases toward the open end surfaces 22C and 22D which are open end surfaces. Yes.

  As described above, when the distal end portion of the distal end side braided body 22A and the proximal end portion of the proximal end side braided body 22B are flared as described above, the distal end portion of the distal end side braided body 22A and the base The proximal end portion of the end side braided body 22 </ b> B is more closely attached to the inner peripheral surface of the artery X. For this reason, it becomes possible to increase the locking force for locking the flow diverter stent 1B in the artery X at a predetermined position.

  Note that, in the base end portion of the base end side braid body 22B having a flare shape, the increase rate of the outer diameter with respect to the unit length along the axial direction is larger than that of the flare shape of the front end side braid body 22A. It is also possible to set by value. Thereby, the latching force which latches the flow diverter stent 1B in the predetermined position in the artery X can further be improved.

(Example 3)
Hereinafter, although the flow diverter stent 1C according to the third embodiment will be described with reference to FIG. 4, the description common to the first and second embodiments is omitted, and the same reference numerals are given in the drawing.

  As shown in FIG. 4, the coil body 32 of the flow diverter stent 1C has a coil outer diameter of a boundary position between the proximal end of the distal end side braided body 23A and the distal end position of the proximal end side braided body 23B. And it is different. Specifically, in the coil body 32, the outer diameter of the coil at the distal end is smaller than the outer diameter of the coil at the proximal end. As a result, the outer diameter of the proximal end portion of the distal end side braided body 23A is made smaller than the outer diameter of the distal end portion of the proximal end side braided body 23B.

  By adopting such a configuration, if the blood vessel diameter of the artery X is thick on the upstream side with respect to the cerebral aneurysm Y and the downstream side is thinner than that, the flow diverter stent 1C is changed according to the size of the blood vessel diameter at each position. It is possible to reliably insert the outer peripheral surface of the distal end side braided body 23A and the proximal end side braided body 23B to the inner peripheral surface of the artery X with certainty.

  Of course, the configuration of the present embodiment and the configuration of the second embodiment can be combined.

Example 4
Hereinafter, although the flow diverter stent 1D concerning Example 4 is demonstrated according to FIG. 5, description is abbreviate | omitted about the part which is common in Examples 1-3, and supposes that the same code | symbol is attached | subjected in a figure.

  As shown in FIG. 5, the flow diverter stent 1 </ b> D includes a distal end side braid body 24 </ b> A and a proximal end side braid body 24 </ b> B, and a coil body 33 made of a single coil as separate bodies. By adopting such a configuration, the materials and the wire diameters of the braided strands 20A and 20B and the coil strands 30 suitable for the respective portions in the distal end side braid 24A, the coil body 33, and the proximal end braid 24B are set. It becomes possible to do.

  In this configuration, the end face of the distal end of the coil body 33 and the end face of the proximal end of the distal end side braid 24A are abutted, and the end face of the proximal end of the coil body 33 and the proximal end braid 24B The end surfaces of the tips of the two are abutted, and the abutted portions are end-joined by laser welding. In addition, as a technique for joining the coil body 33 and the distal end side braid 24A, or the coil body 33 and the proximal end braid 24B, a known technique such as brazing is adopted instead of laser welding. Of course.

  Since the coil body 33 is a single coil, the coil body 33 is rich in flexibility and can be appropriately disposed even if the artery X near the cerebral aneurysm Y is curved or bent in a complicated manner. The coil body 33 may be a multi-strand coil body. When the coil body 33 is formed of a multi-strip coil body, even when the coil body 33 is curved in the artery X, a gap is hardly generated between the coil strands 30, so that blood flowing in the coil body 33 is cerebral aneurysm. It is possible to more reliably prevent the liquid from flowing toward Y.

  The outer diameter of the coil wire 30 of the coil body 33 may be the same as the outer diameter of the braided wires 20A and 20B of the distal end side braid 24A and the proximal end braid 24B. May be different. Moreover, when both outer diameters differ, any may be thin. Further, it is of course possible to apply the configurations of Examples 2 and 3 to the flow diverter stent 1D.

The present invention is not limited to the first to fourth embodiments described above, and it is possible to make design changes or appropriately combine them without departing from the spirit of the present invention.
For example, the distal end side braided bodies 2A, 22A to 24A and the proximal end side braided bodies 2B, 22B to 24B can be configured by one braided strand 20A and one braided strand 20B.

1A to 1D Flow diverter stent 2A, 22A to 24A Front end side braided body 22C, 22D Open end surface 2B, 22B to 24B Base end side braided body 3, 32, 33 Coil body 20A, 20B Braided strand 30 Coil strand

Claims (7)

A flow diverter stent placed in an artery and through which blood flows,
A leading end side braided body composed of a tubular braided body;
A coil body located at the proximal end of the distal-end braid,
A proximal-side braided body that is located at the proximal end of the coil body and is formed of a tubular braided body;
A flow diverter stent comprising: The flow diverter stent according to claim 1,
The braided body constituting the distal end side braided body and the proximal end side braided body is constructed by braiding braided strands formed along one direction and braided strands formed along the other direction. Has been
The coil body is
Of the braided strands in the braided body constituting the distal end side braided body and the proximal end side braided body, the braided strands formed along one direction are removed and formed along the other direction. A flow diverter stent that uses a braided wire as a coil wire. The flow diverter stent according to claim 1,
The said coil body is a flow diverter stent which uses the strand different from the braided strand which forms the braided body which comprises the said front end side braided body and the said base end side braided body as a coil strand. The flow diverter stent according to claim 3,
The coil body is a flow diverter stent, which is a multi-row coil body composed of a plurality of strands. The flow diverter stent according to any one of claims 1 to 4,
The coil body has a constant coil inner diameter over its entire length,
The flow diverter stent, wherein a distal end portion of the distal end side braided body and a proximal end portion of the proximal end side braided body are formed in a flared shape with an outer diameter increasing toward each open end surface. The flow diverter stent according to any one of claims 1 to 4,
The coil outer diameter at the tip of the coil body is smaller than the coil outer diameter at the base end of the coil body, and
A flow diverter stent, wherein an outer diameter of a proximal end of the distal end side braid is smaller than an outer diameter of a distal end of the proximal end braid. The flow diverter stent according to any one of claims 1 to 6,
A flow diverter stent, wherein an outer diameter of a coil wire constituting the coil body and an outer diameter of a braided wire forming the distal end side braid and the proximal end braid are the same.

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