JP6146978B2 - Medical instruments - Google Patents

Description

  The present invention relates to a medical instrument including a shaft.

  As medical instruments to be inserted into the body, those having a shaft such as a catheter or a guide wire are known. In such a medical instrument, there is a medical device in which a force is applied to the shaft so that the shaft can be greatly deformed to a specific side with respect to the axis.

  For example, in the guiding catheter described in Patent Document 1, a curved portion is formed on the distal end side of the shaft. In order to insert the catheter into the body via the sheath introducer, it is necessary to extend the curved portion straight to some extent. That is, the bending portion is greatly deformed to the opposite side to the bending direction so as to be straight.

  Further, in the guide wire placement catheter described in Patent Document 2, a curved portion for guiding the guide wire from the main blood vessel to the side branch is formed on the distal end side of the shaft. When the guide wire placement catheter is further advanced along the guide wire inserted into the side branch, the linear portion of the shaft located on the proximal side of the bending portion is inserted into the side branch while bending in the same direction as the bending portion. It will be followed. That is, when the angle between the main blood vessel and the side branch is large, the linear portion of the shaft is greatly deformed in the same direction as the bending direction of the bending portion at the tip.

  Further, such deformation of the shaft may occur not only when the catheter is used but also when the catheter is manufactured. For example, when a curved portion is formed on a linear catheter shaft, it is conceivable that a core material having a curved shape is inserted into the distal end portion of the linear portion into the shaft and heated to shape the shaft. Thereafter, when the core material is removed from the shaft, the curved portion of the shaft passes through the linear portion of the core material, so that the curved portion of the shaft is straightened.

JP-T-2-501893 International Publication No. 2011/100706

  Here, if the shaft is greatly deformed, plastic deformation occurs, and the shaft may not be restored to its original shape. Therefore, it is conceivable to form the shaft using a material that hardly causes plastic deformation. However, in general, since a material that is difficult to plastically deform has a low rigidity, the rigidity of the catheter shaft is reduced when a material that is difficult to plastically deform is used. As a result, the shaft may not be provided with a desired rigidity.

  This invention is made | formed in view of the said situation, and makes it a main objective to provide the medical instrument which can improve a restoring property, suppressing the fall of the rigidity of a shaft.

The present invention is a medical instrument that is inserted into a body, and includes a shaft having a peripheral wall, the peripheral wall is formed of a first material having a first yield elongation, and one of the peripheral walls in the circumferential direction is formed. A first peripheral wall portion forming a portion, the first material, and a second material having a second yield elongation different from the first yield elongation, and other than the first peripheral wall portion of the peripheral walls A second peripheral wall portion that forms a remaining portion of the second peripheral wall portion , wherein the second peripheral wall portion is formed from an inner region formed from a mixture of the first material and the second material, and the second material. A medical device having a defined outer region .

  When deformation such as bending and stretching occurs in the shaft, tensile strain occurs on one side of the shaft, and compressive strain occurs on the opposite side. Generally, when a tensile strain occurs in a certain material and when a compressive strain occurs, plastic deformation, that is, yield, is more likely to occur when tensile strain occurs.

  Therefore, according to the present invention, in the peripheral wall of the shaft, the first peripheral wall portion is formed of the first material having the first yield elongation, and the second peripheral wall portion is the second material having the first material and the second yield elongation. Including materials. In this case, the first peripheral wall portion and the second peripheral wall portion have different yield elongations. In this case, even if the shaft is deformed and tensile strain is generated in the peripheral wall portion having a high yield elongation of the first peripheral wall portion and the second peripheral wall portion, it is possible to suppress plastic deformation from occurring in the deformed portion. be able to. Therefore, the restoring property of the shaft can be improved.

Also, in general, materials with low yield elongation are stiffer than materials with high yield elongation. Therefore, a material having a low yield elongation out of the first material and the second material can suppress a decrease in the overall rigidity of the peripheral wall of the shaft. In other words, according to the present invention, it is possible to improve the resilience while suppressing a decrease in the rigidity of the shaft.
Furthermore, according to this invention, the inner side area | region of the 2nd surrounding wall part is formed from the mixture of 1st material and 2nd material. In this case, the inner region of the second peripheral wall portion has a high bonding strength with respect to the outer region and the first peripheral wall portion, and there is a possibility that separation occurs on the peripheral wall of the shaft including different materials of the first material and the second material. Can be reduced.

  Further, according to the present invention, the shaft has a curved portion, and the innermost corner of the corner inner portion of the curved portion has a high yield elongation of the first peripheral wall portion and the second peripheral wall portion. It is a medical instrument characterized by being formed by the part.

  When the shaft of the medical device has a curved portion, the shaft may be greatly deformed so that the curved portion is extended during use or manufacture of the medical device. At this time, tensile strain occurs in the corner inner portion of the curved portion, and compressive strain occurs in the outer corner portion. Furthermore, the innermost corner of the corner inner portion is the portion where the tensile strain becomes the largest. Therefore, in the present invention, the innermost corner of the corner inner portion is formed by a peripheral wall portion having a high yield elongation. For this reason, it is possible to suppress the plastic deformation of the inner portion of the corner where the tensile strain occurs, increase the resilience of the shaft, increase the rigidity of the outer portion of the corner where the compressive strain occurs, and thereby suppress the decrease in the rigidity of the shaft. Yes.

  Further, the present invention is the medical instrument characterized in that the inner corner portion is configured not to yield in a state where the curved portion is deformed linearly.

  ADVANTAGE OF THE INVENTION According to this invention, even if a curved part may be extended linearly in use or manufacture of a medical device, a curved part can be restored to the original curved shape without plastic deformation.

  Further, according to the present invention, a peripheral wall portion having a high yield elongation of the first peripheral wall portion and the second peripheral wall portion is formed in the curved portion when a load is applied to the curved portion to extend the curved portion. The medical instrument is arranged so as not to protrude into a compression region where compressive stress is generated.

  According to the present invention, the peripheral wall portion having a high yield elongation is arranged only in the tension region so as not to protrude into the compression region. That is, the lowering of the rigidity of the shaft can be further suppressed by arranging the peripheral wall portion having low rigidity only in the tension region and not in the compression region.

Further, the present invention is the medical instrument, wherein the shaft includes an inner layer provided inside the peripheral wall, and a reinforcing layer provided between the inner layer and the peripheral wall. .
According to the present invention, the rigidity of the shaft can be increased by the reinforcing layer.

The top view of the catheter of one Embodiment. (A) The partially enlarged view of a catheter, (b) Sectional drawing of the 2nd bending part of a catheter. (A) The top view of the tube used for manufacture of a catheter, (b) Sectional drawing of a tube. (A)-(c) The figure for demonstrating the shaping method of a catheter. The figure for demonstrating the usage method of a catheter. (A) The top view of the catheter of other embodiment, (b) Sectional drawing of a catheter. (A)-(g) Sectional drawing of the catheter of other embodiment. (A)-(d) The partial top view of the catheter of other embodiment. (A)-(d) Sectional drawing of the guide wire of other embodiment.

[First Embodiment]
Hereinafter, an embodiment in which the present invention is applied to a guiding catheter for a coronary artery will be described with reference to the drawings. FIG. 1 is a plan view of a guiding catheter 10 according to an embodiment. FIG. 2A is a partially enlarged view of the guiding catheter 10, and FIG. 2B is a cross-sectional view of the second bending portion of the guiding catheter 10.

  A guiding catheter 10 (hereinafter referred to as a catheter 10) is a medical instrument that is inserted into a body, and has a tubular cross-section as a whole as shown in FIGS. 1 and 2B. Specifically, the catheter 10 includes a connector 11 provided at the proximal end and a shaft 12 extending from the connector 11 to the distal end of the catheter 10. The outer diameter of the shaft 12 can be 1 to 3 mm, and preferably 1.3 to 2.5 mm. The inner diameter of the shaft 12 can be set to 0.5 mm to 2.8 mm, preferably 1.0 to 2.1 mm. The wall thickness of the shaft 12 can be 0.05 to 0.5 mm, and preferably 0.1 to 0.2 mm. For example, in this embodiment, the shaft 12 has an inner diameter of 1.8 mm and an outer diameter of 2.1 mm.

  The shaft 12 includes a substantially straight base end side shaft 13 and a front end side shaft 14 provided with a predetermined shape. The proximal shaft 13 is connected to the distal shaft 14 and has rigidity higher than that of the distal shaft 14. The distal end side shaft 14 is composed of a first portion 14a located on the distal end side and a second portion 14b located on the proximal end side.

  A proximal end opening 16 is formed at the proximal end of the catheter 10, and a distal end opening 17 is formed at the distal end of the catheter 10. A lumen 18 having a circular cross section extends along the axis AX of the shaft 12 between the proximal end opening 16 and the distal end opening 17 as shown in FIG. The lumen 18 functions as a passage through which a guide wire, a balloon catheter, a contrast medium, and the like pass.

  Next, the shape of the distal shaft 14 of the catheter 10 will be described. The catheter 10 of the present embodiment has a shape called Judkins Left. As shown in FIG. 1, in the natural state of the catheter 10, the distal shaft 14 has a substantially straight most distal end portion 21, a first bending portion 22 extending from the most distal end portion 21, and a first bending portion 22. An intermediate portion 23 extending from the intermediate portion 23, a second bending portion 24 extending from the intermediate portion 23, and a substantially linear portion 25 extending from the second bending portion 24 and continuing to the proximal end side shaft 13. The most distal portion 21 and the first curved portion 22 form the first portion 14a of the distal end side shaft 14, and the intermediate portion 23, the second curved portion 24, and the substantially straight portion 25 are the second portion 14b of the distal end side shaft 14. Is forming. The natural state is a state in which the catheter 10 is outside the body and is not receiving force from others.

  The substantially straight portion 25 extends in the same straight line as the proximal shaft 13. The first bending portion 22 and the second bending portion 24 are bent in the same direction. The intermediate portion 23 is slightly bent in the same direction as the first bending portion 22 and the second bending portion 24. The intermediate part 23 is substantially parallel to the substantially straight part 25.

  Next, the constituent material of the shaft 12 will be described. As shown in FIG. 2A, the shaft 12 includes a reinforcing layer 31 composed of a plurality of wires 31a. Specifically, as shown in FIG. 2B, the shaft 12 has a substantially circular cross-sectional shape from the distal end to the proximal end, is formed of a plurality of layers, and includes an inner layer 32 and an outer layer as a peripheral wall. 33 and a reinforcing layer 31 provided between the inner layer 32 and the outer layer 33. The reinforcing layer 31 is for increasing the rigidity of the shaft 12, and can be, for example, a braid formed by weaving a plurality of wires 31a. As the braided wire 31a, a flat wire or a round wire formed of a metal such as stainless steel can be used.

  The inner layer 32 and the outer layer 33 can be formed from a synthetic resin. The inner layer 32 is formed of a low friction material, thereby reducing resistance when sliding a guide wire, a balloon catheter or the like in the lumen 18. As a material for forming the inner layer 32, for example, a fluorine-containing resin such as polytetrafluoroethylene can be used.

  Each of the inner layer 32 and the reinforcing layer 31 is formed of the same material in each part of the shaft 12, that is, in the proximal side shaft 13, the first portion 14 a, and the second portion 14 b. On the other hand, the outer layer 33 is made of different materials for the proximal end shaft 13, the first portion 14a, and the second portion 14b. That is, the outer layer 33 includes a first outer layer provided in the first portion 14a, a second outer layer provided in the second portion 14b, and a third outer layer provided in the proximal shaft 13. Have.

  Further, the second outer layer, which is the outer layer 33 of the second portion 14b, has a different configuration on the predetermined side PS with respect to the axis AX of the shaft 12 and the opposite OS. Specifically, the second outer layer includes a first peripheral wall portion 34 that forms a part in the circumferential direction of the second outer layer, and a remaining portion other than the first peripheral wall portion 34 of the second outer layer. And a second peripheral wall portion 35 that forms More specifically, the first peripheral wall portion 34 forms the circumferential half of the second outer layer, and the second peripheral wall portion 35 forms the remaining half of the circumferential direction of the second outer layer. . That is, in the second outer layer, the first peripheral wall portion 34 forms a predetermined side PS with respect to the axis AX, and the second peripheral wall portion forms an opposite side OS with respect to the axis AX. In the present embodiment, the first peripheral wall portion 34 includes a corner inner portion 34I (a portion located inside the bend) of the second curved portion 24 and a corner inner portion 34I of the intermediate portion 23 in the second outer layer. And a portion of the substantially linear portion 25 that is continuous with the corner inner portion 34I. On the other hand, the second peripheral wall portion 35 is connected to the corner outer portion 35O (the portion located outside the bend) of the second curved portion 24 and the corner outer portion 35O of the intermediate portion 23 in the second outer layer. It is formed by a portion on the side and a portion on the side continuous with the corner outer portion 35 </ b> O in the substantially straight portion 25.

  The first outer layer is made of a softer material than the second outer layer and the third outer layer. Regarding the second outer layer, the first peripheral wall portion 34 is formed of a first material having a first yield elongation. On the other hand, the second peripheral wall portion 35 includes a first material and a second material having a second yield elongation different from the first yield elongation. In the present embodiment, the first yield elongation is higher than the second yield elongation. That is, the first material has a higher yield elongation than the second material, and the first material can be referred to as a high yield elongation material and the second material can be referred to as a low yield elongation material. Here, the yield elongation represents the elongation when a certain material yields, and is also called the yield point elongation. A material having a high yield elongation is difficult to yield even when deformed greatly and has a high shape restoring property, but generally has a low rigidity. The rigidity specifically refers to “bending stiffness (bending moment)”, which is a value proportional to the product of Young's modulus (longitudinal elastic modulus) and cross-sectional secondary moment. For example, the first yield elongation of the first material (high yield elongation material) is 10% or more and 100% or less, and the second yield elongation of the second material (low yield elongation material) is 1% or more or 50%. It is good also as follows. More preferably, the first yield elongation may be 30% or more and 80% or less, and the second yield elongation may be 5% or more and less than 30%. Alternatively, the value of (first yield elongation / second yield elongation) may be 1.05 or more, and more preferably 1.1 or more and 10 or less.

  The entire first peripheral wall portion 34 is formed of the first material. That is, the 1st surrounding wall part 34 has the inner side area | region 34a formed from the 1st material, and the outer side area | region 34b similarly formed from the 1st material. The 2nd surrounding wall part 35 has the inner side area | region 35a containing a 1st material and a 2nd material, and the outer side area | region 35b formed from the 2nd material. Specifically, the inner region 35a is formed from a mixture of the first material and the second material. The inner region 35a contains the first material, and the inner regions 34a, 35a contain the first material all around the axis AX. As a whole, the first peripheral wall portion 34 has a higher yield elongation than the second peripheral wall portion 35, and the second peripheral wall portion 35 has higher rigidity than the first peripheral wall portion 34. Here, the 1st surrounding wall part 34 which has the high yield elongation of the 1st surrounding wall part 34 and the 2nd surrounding wall part 35 can also be called the high yield elongation surrounding wall part HE. Moreover, the 2nd surrounding wall part 35 which has the low yield elongation of the 1st surrounding wall part 34 and the 2nd surrounding wall part 35 can also be called the low yield elongation surrounding wall part LE.

  The third outer layer, which is the outer layer 33 of the proximal shaft 13, is made of a material having a rigidity that is greater than the overall rigidity of the second outer layer. That is, for example, the rigidity of the first material and the second material of the second outer layer may be equal to or less than the rigidity of the third outer layer. Alternatively, even if the rigidity of the second material of the second outer layer is greater than that of the third outer layer, the rigidity of the third outer layer is the overall combination of the first peripheral wall portion 34 and the second peripheral wall portion 35. What is necessary is just to become more than the rigidity of a 2nd outer side layer.

  Since the outer layer 33 is configured as described above, in the shaft 12, the second portion 14b has higher rigidity than the first portion 14a, and the proximal shaft 13 has rigidity higher than that of the second portion 14b. Have. That is, the proximal shaft 13 has a rigidity higher than that of the distal shaft 14. The most distal portion 21 and the first bending portion 22 have higher flexibility than the intermediate portion 23, the second bending portion 24, the substantially straight portion 25, and the proximal end side shaft 13.

  As shown in FIG. 1, the most advanced portion 21 includes a protective chip 21 a that is more flexible than the other portions of the most advanced portion 21 at the tip. A slight predetermined region on the tip side of the first portion 14a is not provided with the inner layer 32 and the reinforcing layer 31, and is formed only from the material constituting the first outer layer, which becomes the protective chip 21a. ing. Therefore, the protection chip 21a is more flexible than the other parts of the most advanced portion 21, and is very flexible, so that there is a possibility of damaging the blood vessel even when the tip of the catheter 10 contacts the blood vessel. Has been reduced.

  In order to achieve such a hardness balance, each of the first outer layer, the second outer layer, and the third outer layer constituting the outer layer 33 may be formed from different types of resins, or a plurality of resins may be formed. The hardness change may be achieved by changing the mixing ratio using the mixture. As a material for forming the outer layer 33, for example, polyamide, polyamide elastomer, polyester elastomer, polybutylene terephthalate, or a mixture thereof can be used. Note that each of the first material and the second material forming the first peripheral wall portion 34 and the second peripheral wall portion 35 does not need to be a single material. For example, the first material or the second material has a plurality of types. A material mixed with resin may be used, or a material added with carbon fiber or the like may be used.

  Next, the distortion when the second bending portion 24 of the shaft 12 is extended linearly and the action of the first peripheral wall portion 34 and the second peripheral wall portion 35 related thereto will be described. When a load is applied to the second bending portion 24 so as to extend the second bending portion 24 straight, the second bending portion 24 has a tensile stress inside the corner (the inside of the bending) that becomes the predetermined side PS. Compressive stress is generated outside the corner (outside the bend) that is the opposite OS. Specifically, in the second curved portion 24, tensile stress occurs in a region inside the corner from the axis AX of the shaft 12 (hereinafter referred to as a corner inner region 24I), and a region outside the corner from the axis AX (hereinafter referred to as a corner outer region). Compressive stress occurs at 24O). In this case, the corner inner region 24I is a tensile region in which tensile stress is generated and extends in the axis AX direction, and tensile strain occurs. On the other hand, the corner outer region 24O is a compressed region in which compressive stress is generated and contracts in the direction of the axis AX to generate compressive strain. Here, the corner inner region 24 </ b> I has a corner inner portion 34 </ b> I that is a part of the first peripheral wall portion 34, a part of the reinforcing layer 31, and a part of the inner layer 32. The corner outer region 24O has a corner outer portion 35O that is a part of the second peripheral wall portion 35, a part of the reinforcing layer 31, and a part of the inner layer 32.

  In the second curved portion 24, the boundary surface between the corner inner region 24I and the corner outer region 24O is a neutral surface where no stress is generated. In the corner inner region 24I, the tensile stress and the tensile strain increase in proportion to the distance from the neutral surface, and in the corner outer region 24O, the compressive stress and the compressive strain increase in proportion to the distance from the neutral surface. growing. The boundary surface between the first peripheral wall portion 34 and the second peripheral wall portion 35 is also the neutral surface.

  Generally, when a tensile strain is generated in a certain material and when a compressive strain is generated, the tensile strain is more likely to cause plastic deformation (yield). More specifically, when comparing the ease of plastic deformation under conditions where the tensile strain and the compressive strain are the same, the tensile strain is more likely to undergo plastic deformation (yield). Therefore, when the second bending portion 24 is stretched, the innermost corner inside the corner where the largest tensile strain (and tensile stress) occurs in the second bending portion 24, that is, the portion inside the corner farthest from the neutral surface. It is considered that plastic deformation occurs.

  In the natural state of the catheter 10, the length D1 along the innermost axis AX of the corner of the second bending portion 24 is set as the initial length D1. Here, when the second curved portion 24 is stretched until it becomes straight, the innermost corner is the length D2 of the axis AX of the second curved portion 24 (that is, the length of the neutral plane in the axis AX direction). It will be stretched until it becomes the same. In this case, the innermost corner of the second bending portion 24 extends by a length of D2-D1, in other words, a tensile strain of (D2-D1) / D1 is generated in the innermost corner. Hereinafter, this tensile strain, that is, the largest tensile strain generated in the second bending portion 24 is referred to as maximum tensile strain MS (= (D2-D1) / D1).

  Here, in this embodiment, the corner inner portion 34I including the innermost corner is formed from the first peripheral wall portion 34 of the first material. The first material has a higher yield elongation than the second material included in the second peripheral wall portion 35. More specifically, the first material has a yield elongation that does not yield even when the maximum tensile strain MS occurs. For this reason, the first peripheral wall portion 34, specifically, the corner inner portion 34I does not yield even when the second bending portion 24 is deformed linearly. Further, even when the second bending portion 24 is deformed linearly, the reinforcing layer 31 and the inner layer 32 do not yield. That is, the corner inner region 24I is configured not to yield even when the second bending portion 24 is linearly deformed. Various materials can be used as the first material in order to prevent the corner inner portion 34I from yielding even when the second bending portion 24 is linearly deformed. For example, polybutylene terephthalate (for example, Novaduran) A material mixed with a polyester elastomer (eg, Hytrel) may be used as the first material.

  On the other hand, the second peripheral wall portion 35 includes a second material having a yield elongation lower than that of the first material. However, in the state where the second curved portion 24 is linearly deformed, the second peripheral wall portion 35 Since the generated strain is a compressive strain, the second peripheral wall portion 35 does not yield. In addition, since the second material has higher rigidity than the first material, the second peripheral wall portion 35 gives the shaft 12 the necessary rigidity. Furthermore, since the first peripheral wall portion 34 is disposed so as not to protrude into the compression region, that is, the first peripheral wall portion 34 is disposed only in the tension region, the reduction in rigidity of the shaft 12 is also suppressed from this point. can do.

  Next, the process regarding the 1st surrounding wall part 34 and the 2nd surrounding wall part 35 in the manufacturing process of the catheter 10 is demonstrated. FIG. 3A is a plan view of the tube 40 used for manufacturing the catheter 10, and FIG. 3B is a cross-sectional view of the tube 40.

  In order to form the outer layer 33 of the second portion 14b of the distal end side shaft 14, that is, the first peripheral wall portion 34 and the second peripheral wall portion 35, a resin tube 40 shown in FIGS. 3A and 3B is used. . The tube 40 has a tubular shape with an annular cross section. A lumen 41 having a circular cross section extends from one end to the other end of the tube 40. Tube 40 has an inner and outer diameter that is slightly larger than the second outer layer.

  The tube 40 includes a first wall portion 44 that forms a part in the circumferential direction, and a second wall portion 45 that forms a remaining portion of the first wall portion 44. Specifically, the first wall portion 44 forms a half of the tube 40 in the circumferential direction, and the second wall portion 45 forms the remaining half of the circumferential direction. The first wall portion 44 corresponds to the first peripheral wall portion 34 of the catheter 10, and the second wall portion 45 corresponds to the second peripheral wall portion 35 of the catheter 10.

  The first wall portion 44 is made of a first material. The second wall portion 45 includes a first material and a second material. Specifically, the entire first wall portion 44 is formed of the first material. That is, the first wall portion 44 includes an inner region 44a formed from the first material and an outer region 44b formed from the first material. The second wall portion 45 has an inner region 45a formed from the first material and an outer region 45b formed from the second material. In the second wall portion 45, the inner region 45a is thinner than the outer region 45b.

  Such a tube 40 can be manufactured by extrusion molding. For example, the tube 40 may be manufactured in one step by extruding the first material and the second material simultaneously. Alternatively, after forming a thin tube having only the inner regions 44a and 45a of the tube 40 using the first material, the first material and the second material are simultaneously extruded onto the thin tube, thereby the outer region 44b. 45b may be formed to manufacture the tube 40.

  Forming the second outer layer, that is, the first peripheral wall portion 34 and the second peripheral wall portion 35 by covering the tube 40 from the outside of the reinforcing layer 31 and the inner layer 32 and performing heat welding to the tube 40. Can do. Here, by applying heat, the first material and the second material are melted and partially mixed in the tube 40. Specifically, the first material in the inner region 45a of the second wall 45 and the second material in the outer region 45b of the second wall 45 are mixed. As a result, a mixed region of the first material and the second material is formed at the boundary between the inner region 45a and the outer region 45b of the second wall portion 45 and around the boundary.

  Here, in the tube 40, the inner region 45 a of the second wall 45 is thinner than the outer region 45 b of the second wall 45. For this reason, as shown in FIG. 2B, after heat welding, the inner region 35a of the second peripheral wall portion 35 is a region where the first material and the second material are mixed, and the second wall portion 45 It is thicker than the inner region 45a. Further, the outer region 35 b of the second peripheral wall portion 35 is a region formed from the second material and is thinner than the outer region 45 b of the second wall portion 45.

  Next, a process of shaping the distal end side shaft 14 with respect to the shaft 12 will be described. 4A to 4C are views for explaining a method for shaping the catheter 10. In this step, as shown in FIG. 4A, a metal core 47 having an outer diameter substantially the same as the inner diameter of the distal end side shaft 14 and substantially the same shape as the distal end side shaft 14 is used. Specifically, the core material 47 has a linear base end side portion 47 a corresponding to the base end side shaft 13 and the substantially straight portion 25, and a curved shape corresponding to the leading end portion 21 to the second bending portion 24. And a distal end portion 47b.

  First, the shaft 12 is arranged on the outer peripheral side of the core material 47 by moving the shaft 12 while pulling the core material 47 through the lumen 18 of the shaft 12 while pulling the shaft 12 toward the distal end side. In this case, as shown in FIG. 4B, the shaft 12 is disposed so that the shaft 12 extends from the proximal end portion 47 a to the distal end portion 47 b of the core material 47. At this time, in the distal end side portion 47b, the circumferential direction of the shaft 12 is such that the first peripheral wall portion 34 of the shaft 12 is positioned inside the corner (inner side of the bend) and the second peripheral wall portion 35 is positioned outside the corner (outside of the bend). Adjust the direction of the position.

  Next, the distal end side shaft 14 is shaped by heating the distal end side shaft 14 under a predetermined heating condition. In this case, for example, the tip side shaft 14 is heated for several tens of seconds to several minutes under a temperature condition of 100 to 300 ° C. Thereby, the shape from the most advanced part 21 to the 2nd curved part 24 can be provided to the front end side shaft 14.

  Thereafter, as shown in FIG. 4C, the shaft 12 is removed from the core material 47 by moving the shaft 12 while pulling the shaft 12 toward the proximal end side with respect to the core material 47. In this case, since the second curved portion 24 passes through the proximal end portion 47a of the core material 47, the second curved portion 24 is linearly formed, that is, on the opposite side to the bent side of the second curved portion 24. It will be stretched. Therefore, there is a concern that plastic deformation occurs in the second bending portion 24. In this regard, in the present embodiment, as described above, when the second bending portion 24 is stretched, tensile stress is generated in the corner inner region 24I in the second bending portion 24, and the outer layer in the corner inner region 24I. A corner inner portion 34I which is 33 is formed from a first peripheral wall portion 34 having a high yield elongation. For this reason, it is possible to suppress the plastic deformation from occurring in the corner inner portion 34I, and consequently to suppress the plastic deformation from occurring in the second bending portion 24. Specifically, since the first peripheral wall portion 34 uses the first material having a yield elongation that does not yield even when the maximum tensile strain MS occurs, even when the second curved portion 24 is straightened. It is possible to prevent plastic deformation from occurring in the second bending portion 24. Therefore, after the shaft 12 is removed from the core material 47, the second bending portion 24 is restored to the original curved shape. Further, the first bending portion 22 is less curved than the second bending portion 24, and the first outer layer of the first bending portion 22 is more flexible than the second outer layer of the second bending portion 24. Since it is formed of a material, the first bending portion 22 is restored to its original shape even when it is straightened. This completes the shaping of the distal shaft 14.

  Next, a method for using the catheter 10 will be described. FIG. 5 is a view for explaining a method of using the catheter 10.

  First, a catheter introducer (hereinafter referred to as an introducer) is inserted into the femoral artery, and then the catheter 10 is inserted into the introducer. At this time, the catheter 10 is inserted into the introducer sequentially from the most distal end portion 21, but the second bending portion 24 is inserted into the introducer while being stretched. Further, the second bending portion 24 is also extended in the blood vessel.

  Here, as described above, the second portion 14 b of the distal shaft 14 has the first peripheral wall portion 34 having a high yield elongation so as to suppress plastic deformation of the second bending portion 24. For this reason, even if the 2nd bending part 24 is extended straight, the restoring property is improved, without plastically deforming.

  The catheter 10 is inserted as it is through the descending aorta DA and the ascending aorta AA to the left coronary artery LA. At this time, a guide wire may be used as necessary. Then, as shown in FIG. 5, the most distal end portion 21 of the catheter 10 is engaged with the left coronary artery LA. In the indwelling state of the catheter 10, the second bending portion 24 is stretched more than the natural state, and the most distal portion 21 is pressed toward the left coronary artery LA by the return elastic force of the second bending portion 24. It becomes a state. Here, in the catheter 10, since the resilience of the second bending portion 24 is enhanced, the return elastic force of the second bending portion 24 even after passing through the blood vessel while the second bending portion 24 is stretched. Will not drop. Therefore, it is possible to improve the insertion and pressing state of the most distal portion 21 to the left coronary artery LA into the left coronary artery LA. That is, good backup performance can be obtained. Moreover, since the 2nd part 14b of the front end side shaft 14 has the 2nd surrounding wall part 35 which has low yield elongation, the rigidity fall of the 2nd curved part 24 is suppressed, and it is favorable also from this point. Backup performance can be obtained.

  Thereafter, a PTCA guide wire is inserted into the left coronary artery LA through the lumen 18 of the catheter 10, and a treatment catheter such as a balloon catheter reaches the lesioned part of the left coronary artery LA along the guide wire to perform treatment.

  The backup property will be described below. In order to push the balloon catheter or the like in the left coronary artery LA, the balloon catheter or the like may be pushed with a strong force. At this time, a force directed toward the distal side of the left coronary artery LA acts on the balloon catheter or the like, and as a reaction, a force directed toward the wall of the ascending aorta AA facing the left coronary artery LA acts on the catheter 10. . That is, while receiving the reaction, the catheter 10 supports the balloon catheter or the like from traveling toward the distal side of the left coronary artery LA against the reaction. In this way, the performance of supporting the balloon catheter or the like so that the balloon catheter or the like advances from the catheter 10 to the back of the blood vessel is called backup property.

  The catheter 10 can be inserted into the body not only from the femoral artery but also from other blood vessels. For example, the catheter 10 may be inserted from the radial artery into the body.

As mentioned above, according to the structure of this embodiment explained in full detail, the following outstanding effects are acquired.
The catheter 10 inserted into the body includes a shaft 12 having an outer layer 33 as a peripheral wall. The outer layer 33 is formed of a first material having a first yield elongation, a first peripheral wall portion 34 that forms a part of the outer layer 33 in the circumferential direction, a first material, and a first yield elongation. And a second material having a second yield elongation different from that of the outer peripheral layer 33 and forming a remaining part other than the first peripheral wall part 34 of the outer layer 33. When the shaft 12 undergoes deformation such as bending and stretching, tensile strain occurs on one side of the shaft 12 and compressive strain occurs on the opposite side. Generally, when a tensile strain occurs in a certain material and when a compressive strain occurs, plastic deformation, that is, yield, is more likely to occur when tensile strain occurs. Therefore, in this configuration, in the outer layer 33 of the shaft 12, the first peripheral wall portion 34 is formed of the first material having the first yield elongation, and the second peripheral wall portion 35 has the first material and the second yield elongation. And a second material. In this case, the first peripheral wall portion 34 and the second peripheral wall portion 35 have different yield elongations. The shaft 12, specifically, the second portion 14 b of the distal end side shaft 14 is deformed, and the high yield elongation peripheral wall portion HE having a high yield elongation of the first peripheral wall portion 34 and the second peripheral wall portion 35 (this In the embodiment, even if a tensile strain occurs in the first peripheral wall portion 34), it is possible to suppress plastic deformation from occurring in the deformed portion. Therefore, the restoring property of the shaft 12 can be improved.

  Also, in general, materials with low yield elongation are stiffer than materials with high yield elongation. Therefore, a decrease in the overall rigidity of the outer layer 33 of the shaft 12 can be suppressed by a material having a low yield elongation of the first material and the second material. In other words, according to the present embodiment, it is possible to improve the recoverability while suppressing a decrease in the rigidity of the shaft 12.

  The shaft 12 has a second curved portion 24, and the corner innermost portion of the corner inner portion 34 </ b> I of the second curved portion 24 is a high yield having a high yield elongation of the first peripheral wall portion 34 and the second peripheral wall portion 35. It is formed by the elongation peripheral wall portion HE (in this embodiment, the first peripheral wall portion 34). The shaft 12 of the catheter 10 has the second bending portion 24, and the shaft 12 may be greatly deformed so that the second bending portion 24 is extended during use or manufacture of the catheter 10. At this time, tensile strain occurs in the corner inner portion 34I of the second curved portion 24, and compressive strain occurs in the corner outer portion 35O. Furthermore, the corner innermost portion of the corner inner portion 34I is a portion where the tensile strain becomes the largest. Therefore, in this embodiment, the innermost corner of the corner inner portion 34I is formed by the first peripheral wall portion 34 having a high yield elongation. For this reason, it is possible to suppress the plastic deformation of the corner inner portion 34I in which the tensile strain occurs, increase the restoring property of the shaft 12, and increase the rigidity of the corner outer portion 35O in which the compressive strain occurs, thereby reducing the rigidity of the shaft 12. Is suppressed.

  The corner inner portion 34I is configured not to yield in a state where the second bending portion 24 is linearly deformed. In this case, even if the second bending portion 24 is stretched in a straight line during use or manufacture of the catheter 10, the second bending portion 24 can be restored to the original curved shape without plastic deformation. it can.

  Of the first peripheral wall portion 34 and the second peripheral wall portion 35, the first peripheral wall portion 34 having a high yield elongation is second bent when a load is applied to the second curved portion 24 to extend the second curved portion 24. The portion 24 is arranged so as not to protrude into a compression region where compressive stress occurs. That is, the lowering of the rigidity of the shaft 12 can be further suppressed by arranging the first peripheral wall portion 34 having low rigidity only in the tension region and not in the compression region.

  The 2nd surrounding wall part 35 has the inner side area | region 35a formed from the mixture of 1st material and 2nd material, and the outer side area | region 35b formed from 2nd material. In this case, the inner region 35a of the second peripheral wall portion 35 has a high bonding strength with respect to the outer region 35b and the first peripheral wall portion 34, and the peripheral wall of the shaft 12 includes different materials such as the first material and the second material. It is possible to reduce the possibility of peeling on the outer layer 33.

  The shaft 12 includes an inner layer 32 provided on the inner side of the outer layer 33, and a reinforcing layer 31 provided between the inner layer 32 and the outer layer 33. In this case, the rigidity of the shaft 12 can be increased by the reinforcing layer 31.

  In the 2nd curved part 24, the boundary surface of the 1st surrounding wall part 34 and the 2nd surrounding wall part 35 was made into the neutral surface. In the neutral plane, no stress is generated when the second bending portion 24 is extended, and therefore it is possible to suppress the generation of a large shearing force at the boundary surface between the first peripheral wall portion 34 and the second peripheral wall portion 35. Thereby, a possibility that peeling etc. may arise in the 1st surrounding wall part 34 and the 2nd surrounding wall part 35 can be reduced.

  The first peripheral wall portion 34 forms a half in the circumferential direction of the second outer layer, and the second peripheral wall portion 35 forms the remaining half in the circumferential direction of the second outer layer. And the 1st surrounding wall part 34 is formed from the 1st material, and the 2nd surrounding wall part 35 contains the 1st material and the 2nd material. That is, the outer layer 33 of the second portion 14b contains more first material than second material. Therefore, the restoring property of the second portion 14b, and hence the restoring property of the second bending portion 24, can be further improved.

[Second Embodiment]
Hereinafter, an embodiment in which the present invention is applied to a contrast catheter will be described with reference to the drawings. FIG. 6A is a plan view of the contrast catheter 50 in the present embodiment, and FIG. 6B is a cross-sectional view of the catheter 50. Note that the description of the same points as in the first embodiment will be omitted as appropriate.

  The contrast catheter 50 (hereinafter referred to as the catheter 50) is a medical instrument for injecting a contrast medium into a coronary artery. As shown in FIG. 6A, the catheter 50 includes a connector 11 and a shaft 52. A proximal end opening 16 is formed at the proximal end of the catheter 50, and a distal end opening 17 is formed at the distal end of the catheter 50. A lumen 18 through which the contrast medium passes is formed between the proximal end opening 16 and the distal end opening 17.

  The shaft 52 has the same shape as the shaft 12 of the first embodiment. The shaft 52 includes a substantially straight base end side shaft 53 and a front end side shaft 54 having a predetermined shape. The distal end side shaft 54 includes a substantially straight most distal portion 61, a first curved portion 62 extending from the most distal portion 61, an intermediate portion 63 extending from the first curved portion 62, and an extended portion from the intermediate portion 63. The second bending portion 64 is provided, and a substantially straight portion 65 extending from the second bending portion 64 and continuing to the proximal end side shaft 53 is provided.

  The shaft 52 has a material configuration different from that of the shaft 12 of the first embodiment. The shaft 52 is formed of a tubular peripheral wall 55 formed of a synthetic resin, and does not have the reinforcing layer 31 and the inner layer 32 as in the first embodiment. The peripheral wall 55 is formed of different materials for the proximal shaft 53 and the distal shaft 54. The front end side shaft 54 has a different configuration on a predetermined side PS with respect to the axis AX of the front end side shaft 54 and the opposite side OS. Specifically, the peripheral wall 55 of the distal shaft 54 includes a first peripheral wall portion 74 that forms a part of the peripheral wall 55 in the circumferential direction, and a remaining portion other than the first peripheral wall portion 74 of the peripheral wall 55. And a second peripheral wall portion 75 to be formed. More specifically, the first peripheral wall portion 74 forms a half of the peripheral wall 55 in the circumferential direction, and the second peripheral wall portion 75 forms the remaining half of the peripheral wall 55 in the circumferential direction. The first peripheral wall portion 74 includes a corner outer portion 74O, a portion of the first curved portion 62 and the intermediate portion 63 that is continuous with the corner outer portion 74O, and a side of the substantially straight portion 65 that is continuous with the corner outer portion 74O. The part is formed from. On the other hand, the second peripheral wall portion 75 includes a corner inner portion 75I, a portion of the first curved portion 62 and the intermediate portion 63 that is connected to the corner inner portion 75I, and a corner inner portion 75I of the substantially straight portion 65. And a portion on the continuous side.

  The most advanced portion 61 is formed of a material different from that of the first peripheral wall portion 74 and the second peripheral wall portion 75. Specifically, the most distal portion 61 is formed of a material that is more flexible than the first peripheral wall portion 74, the second peripheral wall portion 75, and the proximal end side shaft 53.

  The first peripheral wall portion 74 is formed of a first material having a first yield elongation. On the other hand, the second peripheral wall 75 includes a first material and a second material having a second yield elongation different from the first yield elongation. The second yield elongation is higher than the first yield elongation. That is, the second material has a higher yield elongation than the first material.

  The entire first peripheral wall portion 74 is made of the first material. That is, the 1st surrounding wall part 74 has the inner side area | region 74a formed from the 1st material, and the outer side area | region 74b similarly formed from the 1st material. The 2nd surrounding wall part 75 has the inner side area | region 75a formed from the 1st material, and the outer side area | region 75b formed from the 2nd material. Therefore, as a whole, the first peripheral wall portion 74 has higher rigidity than the second peripheral wall portion 75, and the second peripheral wall portion 75 has a higher yield elongation than the first peripheral wall portion 74. . That is, the first peripheral wall portion 74 is a low yield elongation peripheral wall portion LE, and the second peripheral wall portion 75 is a high yield elongation peripheral wall portion HE.

  The proximal shaft 53 is formed of a material having a rigidity that is greater than the overall rigidity of the distal shaft 54. As a material constituting the peripheral wall 55 of the shaft 52, the same synthetic resin as in the first embodiment can be used.

  When a load is applied to the second bending portion 64 so as to extend the second bending portion 64 straight, tensile stress is generated in the corner inner portion 75I and the corner bending portion 75I extends. Here, the innermost corner of the corner inner portion 75 </ b> I is formed from the outer region 75 b of the second peripheral wall 75. The outer region 75b does not yield because it is formed of the second material having a yield elongation that does not yield even when the maximum tensile strain MS occurs.

  On the other hand, in the corner inner portion 75I, the inner region 75a of the second peripheral wall portion 75 is formed of a first material having a yield elongation lower than that of the second material. However, the inner region 75a is closer to the neutral plane than the outer region 75b, and the tensile strain generated in the inner region 75a is smaller than that of the outer region 75b. Further, the inner region 75a forms only a part of the thickness direction (the radial direction of the shaft 52) of the peripheral wall 55 of the shaft 52, and is relatively thin. In general, in the same material, even when the same degree of tensile strain occurs, a material formed thinner than a material formed thicker is less likely to yield. From these things, even if it is a case where the 2nd curved part 64 is extended, the inner side area | region 75a of the 2nd surrounding wall part 75 does not yield. That is, even when a load is applied to the second bending portion 64 so as to extend the second bending portion 64 straight, the corner inner portion 75I, that is, the second peripheral wall portion 75 is not plastically deformed. .

  In order to form the first peripheral wall portion 74 and the second peripheral wall portion 75 of the catheter 50, a tube having the cross-sectional configuration of FIG. The first peripheral wall portion 74 and the second peripheral wall portion 75 can be formed by joining such a tube to the proximal end side shaft 53.

  As mentioned above, according to this embodiment explained in full detail, the following outstanding effects are acquired. Note that description of effects similar to those of the first embodiment will be omitted.

  The first circumferential wall portion 74 forms a half of the circumferential wall 55 in the circumferential direction, and the second circumferential wall portion 75 forms the remaining half of the circumferential wall 55 in the circumferential direction. And the 1st surrounding wall part 74 is formed from the 1st material, and the 2nd surrounding wall part 75 contains the 1st material and the 2nd material. That is, the peripheral wall 55 of the distal end side shaft 54 contains more first material than second material. Therefore, it is possible to further suppress a decrease in the rigidity of the distal end side shaft 54 and, consequently, the rigidity of the second bending portion 64.

  The first curved portion 62 has a first peripheral wall portion 74 and a second peripheral wall portion 75. In this case, even if the first curved portion 62 is straightened and further bent in the stretched direction as it is, the first curved portion 62 is not plastically deformed, and the original shape is obtained. Can be restored.

[Other Embodiments]
(1) In 1st Embodiment, the 2nd surrounding wall part 35 has the inner side area | region 35a formed from the mixture of 1st material and 2nd material, and the outer side area | region 35b formed from 2nd material. It was. Here, in the first embodiment, by changing the conditions when the tube 40 is thermally welded to the reinforcing layer 31 and the inner layer 32, the entire second peripheral wall portion 35 is made of the first material and the second material. You may make it form from the mixture of these. That is, the inner region 35a and the outer region 35b of the second peripheral wall portion 35 may be formed from a mixture of the first material and the second material. Even in this case, the two peripheral wall portions 35 have a relatively high bonding strength with respect to the first peripheral wall portion 34, and the possibility that the outer layer 33 including different materials of the first material and the second material is peeled off is reduced. can do.

  (2) In the first embodiment, the tube 40 is used to form the second outer layer. By changing this, in the catheter 10 of the first embodiment, the second outer layer may be formed using a tube for forming the distal end side shaft 54 of the second embodiment. In this case, the second material has a higher yield elongation than the first material. The second outer layer of the shaft of the catheter 10 has a first peripheral wall portion formed from the first material as a corner outer portion. The second outer layer has a second peripheral wall portion having an inner region made of a mixture of the first material and the second material and an outer region made of the second material as a corner inner portion. The reinforcing layer 31 and the inner layer 32 are provided inside these peripheral walls.

  Moreover, in the catheter 50 of 2nd Embodiment, you may form a front end side shaft using the tube 40 of 1st Embodiment. In this case, the first material has a higher yield elongation than the second material. The distal shaft of the catheter 50 has a first peripheral wall portion formed from the first material as a corner inner portion. The second outer layer has a second peripheral wall portion having an inner region formed of the first material and an outer region formed of the second material as a corner outer portion.

  Of the first material and the second material, a material having a high yield elongation is designated as a high yield elongation material, and a material having a low yield elongation is designated as a low yield elongation material. The ratio of the high yield elongation material to the sum of the high yield elongation material and the low yield elongation material with respect to the amount of the constituent material of the shaft (peripheral wall) only needs to be larger in the corner inner portion than in the corner outer portion. More specifically, the inner corner portion may contain more high yield elongation material than the lower yield elongation material, and the outer corner portion may contain more low yield elongation material than the high yield elongation material. .

  (3) The above embodiment may be modified such that only the second curved portions 24 and 64 have the first peripheral wall portions 34 and 74 and the second peripheral wall portions 35 and 75. In this case, what is necessary is just to form parts other than the 2nd curved parts 24 and 64 in the front end side shafts 14 and 54 with a single material in the circumferential direction. For example, the rigidity of the distal shafts 14 and 54 can be increased by forming the substantially straight portions 25 and 65 using a material having high rigidity of the first material and the second material. That is, it is only necessary that at least a part of the outer layer 33 or the peripheral wall 55 in the axis AX direction has the first peripheral wall portions 34 and 74 and the second peripheral wall portions 35 and 75. Note that the entire outer layer 33 of the first embodiment or the entire peripheral wall 55 of the second embodiment may include the first peripheral wall portions 34 and 74 and the second peripheral wall portions 35 and 75.

  (4) In the above embodiment, the corner inner portions 34I and 75I are configured not to yield even when the second bending portions 24 and 64 are linearly deformed. However, the present invention is not limited to this, and the corner inner portions 34I and 75I may yield in a state where the second bending portions 24 and 64 are linearly deformed. Even in this case, by forming the corner inner portions 34I and 75I from the high yield elongation peripheral wall HE, the degree of yield can be reduced, that is, the plastic deformation after the yield can be reduced. Thereby, the restoring property of a shaft can be improved.

  (5) In the above-described embodiment, the first peripheral wall portions 34 and 74 and the second peripheral wall portions 35 and 75 are symmetrical with respect to the axis AX in the direction perpendicular to the axis AX. By changing this, the first peripheral wall portion and the second peripheral wall portion may be asymmetric with respect to the axis of the shaft. That is, one of the first peripheral wall portion and the second peripheral wall portion may form more than half of the peripheral wall in the circumferential direction, and the other may form the remaining portion in the circumferential direction. Fig.7 (a)-(g) is sectional drawing of the catheter of other embodiment. In FIGS. 7A to 7G, the hatching as shown in FIGS. 3B and 6B is omitted for the sake of convenience for the first and second peripheral wall portions located around the lumen 18. doing.

  For example, in Fig.7 (a), the 1st surrounding wall part 81 forms the part smaller than the half of the circumferential direction among the surrounding walls 80 of a shaft. The second peripheral wall portion 82 forms a portion of the peripheral wall 80 that is larger than half of the circumferential direction. The 1st surrounding wall part 81 is formed from the 1st material. That is, the first peripheral wall portion has an inner region 81a formed from the first material and an outer region 81b formed from the first material. The 2nd surrounding wall part 82 has the inner side area | region 82a formed from the 1st material, and the outer side area | region 82b formed from the 2nd material. Here, the side of the first peripheral wall portion 81 may be the corner inside (predetermined side) of the second bending portions 24 and 64 of the catheters 10 and 50. In this case, the first material has a higher yield elongation than the second material. Alternatively, the side of the second peripheral wall portion 82 may be the corner inside (predetermined side) of the second bending portions 24 and 64 of the catheters 10 and 50. In this case, the second material has a higher yield elongation than the first material. In this configuration, the second peripheral wall portion 82 which is a high yield elongation peripheral wall portion is bent when a load is applied to the second curved portions 24 and 64 in order to extend the second curved portions 24 and 64 which are curved portions. The portions 24 and 64 protrude into a compression region where compressive stress occurs. Here, the second peripheral wall portion 82 (high elongation peripheral wall portion) may form a portion of the peripheral wall 80 that is 3/4 or less in the circumferential direction. That is, the first peripheral wall portion 81 (low elongation peripheral wall portion) may form a portion of the peripheral wall 80 that is larger than ¼ of the circumferential direction.

  As shown in FIG. 7 (b), the first peripheral wall portion 81 forms a portion larger than half of the circumferential wall 80 of the shaft, and the second peripheral wall portion 82 extends in the circumferential direction of the peripheral wall 80. A portion smaller than half may be formed.

  (6) In the above embodiment, in the outer region of the peripheral wall, the boundary between the first peripheral wall portion and the second peripheral wall portion is provided along the radial direction of the peripheral wall. By changing this, for example, as shown in FIG. 7C, in the outer regions 81b and 82b of the peripheral wall 80, the boundary between the first peripheral wall portion and the second peripheral wall portion is inclined with respect to the radial direction of the peripheral wall. Also good.

  (7) In the above embodiment, the inner region of the second peripheral wall portion has a uniform thickness in the circumferential direction of the peripheral wall. However, the thickness of the inner region of the second peripheral wall portion may be changed in the circumferential direction. . For example, as shown in FIG. 7 (d), the inner region 82 a of the second peripheral wall portion 82 may become thinner as the distance from the first peripheral wall portion 81 increases.

  (8) In the said embodiment, the 2nd surrounding wall part was formed from the inner side area | region and the outer side area | region. By changing this, for example, as shown in FIG. 7E, the second peripheral wall portion 82 may have an intermediate region 82c in addition to the inner region 82a and the outer region 82b. Alternatively, as shown in FIG. 7F, an additional region 82d may be formed in a part of the outer region 82b of the second peripheral wall portion 82. The intermediate region 82c and the additional region 82d can be formed from a third material having a yield elongation different from both the first material and the second material. Alternatively, the intermediate region 82c and the additional region 82d can be formed from a mixture of the first material and the second material.

  (9) As shown in FIG. 7G, the entire second peripheral wall portion 82 may be formed of a mixture of the first material and the second material. That is, both the inner region 82a and the outer region 82b of the second peripheral wall portion 82 may be formed from a mixture of the first material and the second material. Even in this case, the two peripheral wall portions have a relatively high bonding strength with respect to the first peripheral wall portion, thereby reducing the possibility that the peripheral wall of the shaft including different materials, ie, the first material and the second material, is peeled off. Can do.

  (10) A tube having a cross-sectional configuration shown in FIGS. 7A to 7G is covered from the outside of the reinforcing layer 31 and the inner layer 32 of the first embodiment, and the catheter is thermally welded to the tube. You may form a 1st surrounding wall part and a 2nd surrounding wall part. In this case, at the boundary between different materials (for example, between the first material and the second material) and around the boundary, the different materials are melted and mixed. As a result, a mixed region is formed around the boundary.

  (11) The shape of the tip side shaft is arbitrary. FIGS. 8A to 8D are partial plan views of catheters of other embodiments. For example, the shape shown in FIGS. 8A and 8B may be used. The distal shaft 90 shown in FIG. 8A has a straight leading edge portion 91, a curved portion 92, and a substantially straight portion 93. The front end side shaft 95 shown in FIG. 8B has a curved leading end portion 96, a curved portion 92, and a substantially straight portion 93. The most distal portion 96 is bent in the direction opposite to the bending portion 92.

  (12) The arrangement state of the first peripheral wall portion and the second peripheral wall portion is not limited to the above embodiment. For example, the peripheral wall part (high yield elongation peripheral wall part HE) which has high yield elongation of the 1st peripheral wall part and the 2nd peripheral wall part, and the low yield elongation of the 1st peripheral wall part and the 2nd peripheral wall part. The peripheral wall part (low yield elongation peripheral wall part LE) which it has may be arrange | positioned as shown to Fig.8 (a). The most advanced portion 91 has a high yield elongation peripheral wall portion HE and a low yield elongation peripheral wall portion LE arranged in a direction orthogonal to the axis AX. The corner inner region of the curved portion 92 has a high yield elongation peripheral wall portion HE, and the corner outer region of the curved portion 92 has a low yield elongation peripheral wall portion LE. The high yield elongation peripheral wall HE of the most advanced portion 91 is continuous with the low yield elongation peripheral wall LE in the corner outer region of the curved portion 92 in the direction of the axis AX. The low yield elongation peripheral wall portion LE of the most advanced portion 91 is continuous with the high yield elongation peripheral wall portion HE in the corner inner region of the curved portion 92 in the direction of the axis AX. In FIGS. 8A and 8B, dots are attached to the high yield elongation peripheral wall HE for convenience.

  Here, the case where the shaping process of the front end side shaft 90 is performed in the same manner as the shaping process of the front end side shaft 14 will be described. When the distal end side shaft 90 formed with the curved portion 92 is pulled out from the core material to the proximal end side, the most distal end portion 91 passes through the curved distal end side portion of the core material. At this time, the most distal end portion 91 is curved along the tip side portion. Here, the high yield elongation peripheral wall portion HE of the most advanced portion 91 is located outside the curved corner of the tip side portion, but the high yield elongation peripheral wall portion HE has a high yield elongation, so plastic deformation. Can be suppressed. Thereby, the restoring property of the front end side shaft 90 can be improved.

  (13) As shown in FIG. 8B, in the tip side shaft 95, the corner inner region of the most distal portion 96 has a high yield elongation peripheral wall portion HE, and the corner outer region of the most distal portion 96 is low. It has a yield elongation peripheral wall LE. The high yield elongation peripheral wall portion HE of the most advanced portion 96 is continuous with the low yield elongation peripheral wall portion LE in the corner outer region of the curved portion 92 in the direction of the axis AX. The low yield elongation peripheral wall portion LE of the most advanced portion 96 is continuous with the high yield elongation peripheral wall portion HE in the corner inner region of the curved portion 92 in the direction of the axis AX.

  Also in the case of performing the shaping process of the distal end side shaft 95 in the same manner as the shaping process of the distal end side shaft 14 described above, the distal end side shaft 95 in which the curved portion 92 and the curved most distal end portion 96 are formed is formed from the core material. It is necessary to pull it out to the base end side. When the most distal portion 96 passes through the distal end portion of the core corresponding to the curved portion 92, the most distal portion 96 is bent in a direction opposite to the shaped bending direction, and tensile strain is generated in the corner inner region of the most distal portion 96. . Here, since the corner inner side area | region of the most advanced part 96 has the high yield elongation surrounding wall part HE, it can suppress that plastic deformation arises.

  (14) In the above embodiment, the division ratio between the first peripheral wall portion and the second peripheral wall portion in the cross section of the peripheral wall is constant over the entire region in the axis AX direction of the distal end side shaft. You may change this and may change the division | segmentation ratio of a 1st surrounding wall part and a 2nd surrounding wall part along an axis line AX direction. For example, as shown in FIG. 8C, even if the ratio of the high yield elongation peripheral wall portion HE to the entire transverse section of the distal end side shaft 100 is increased stepwise from the proximal end side toward the distal end side. Good. In this case, the ratio of the low yield elongation peripheral wall portion LE occupying the entire transverse section of the distal shaft 100 is gradually reduced from the proximal end toward the distal end. In this configuration, the rigidity of the distal shaft 100 is improved from the proximal end toward the distal end, so that the kink resistance of the distal shaft 100 is improved.

  Further, as shown in FIG. 8D, in the distal end side shaft 105, the ratio of the high yield elongation peripheral wall portion HE occupying the entire transverse section of the distal end side shaft 105 is continuously increased from the proximal end side toward the distal end side. You may make it bigger. In this case, since the rigidity of the distal end side shaft 105 decreases smoothly from the proximal end side toward the distal end side, the kink resistance is further improved.

  (15) One or both of the first material and the second material may be mixed with a metal powder such as tungsten or a ceramic powder such as bismuth oxide or barium sulfate as a contrast material. When contrast material powder is mixed with the resin material, the elastic modulus of the resin material increases and a material having a low yield elongation can be obtained. Therefore, the yield elongation of the first material and the second material can be made different also by such a method. Moreover, the yield elongation of the first material and the second material can be made different by including different amounts of powder.

  (16) In the above embodiment, the first peripheral wall portions 34, 74, 81 and the second peripheral wall portions 35, 75, 82 are formed in the curved portion of the catheter. The first peripheral wall portion and the second peripheral wall portion may be formed. For example, in a guide wire placement catheter for guiding a guide wire from a main blood vessel to a side branch (hereinafter referred to as a placement catheter), the placement catheter is inserted into the side branch along the guide wire inserted into the side branch. There is. At this time, the straight portion of the shaft of the placement catheter is inserted into the side branch while being bent at the branch portion between the main blood vessel and the side branch. At this time, compressive strain is generated inside the corner of the curved shaft, and tensile strain is generated outside the corner. For this reason, by forming the first peripheral wall portion and the second peripheral wall portion on the shaft, it is possible to improve the recoverability while suppressing a decrease in the rigidity of the shaft of the placement catheter. Specifically, the low yield elongation peripheral wall portion LE of the first peripheral wall portion and the second peripheral wall portion is arranged on the side that becomes the corner inner side when the shaft is curved, and the corner outer side when the shaft is curved. What is necessary is just to arrange | position the high yield elongation peripheral wall part HE among the 1st surrounding wall part and the 2nd surrounding wall part to become. That is, in a catheter that is more likely to have a larger tensile strain on the predetermined side than the opposite side with respect to the axis of the shaft, a high yield elongation peripheral wall portion is formed on the predetermined side of the shaft, and the opposite side For this, a low yield elongation peripheral wall portion may be formed.

  (17) In the above embodiment, the first peripheral wall portion and the second peripheral wall portion are provided for the tubular, that is, hollow shaft, but the first peripheral wall is changed for the solid shaft by changing this. You may provide a part and a 2nd surrounding wall part. For example, in a guide wire in which a bending portion is formed at the distal end portion, a first peripheral wall portion and a second peripheral wall portion may be formed in the bending portion. 9A to 9D are cross-sectional views of a guide wire according to another embodiment.

  As shown in FIG. 9A, the guide wire shaft 110 (peripheral wall) has a first peripheral wall portion 111 and a second peripheral wall portion 112. The 1st surrounding wall part 111 has the inner side area | region 111a formed from the 1st material, and the outer side area | region 111b similarly formed from the 1st material. The 2nd surrounding wall part 112 has the inner side area | region 112a formed from the 1st material, and the outer side area | region 112b formed from the 2nd material. Since the second material has a yield elongation different from that of the first material, the first peripheral wall portion 111 and the second peripheral wall portion 112 as a whole have different yield elongations. The corner inner portion of the curved portion of the shaft 110 is formed by the high yield elongation peripheral wall portion HE having a high yield elongation of the first peripheral wall portion 111 and the second peripheral wall portion 112. In the circumferential direction of the shaft 110, the second peripheral wall portion 112 occupies a larger proportion than the first peripheral wall portion 111. Alternatively, as shown in FIG. 9B, the first peripheral wall 111 may occupy a larger proportion than the second peripheral wall 112 in the circumferential direction of the shaft 110.

  As shown in FIG. 9C, the inner region 112a and the outer region 112b of the second peripheral wall 112 of the shaft 110 may be formed to have a thickness that varies in the circumferential direction. At this time, in the cross section of the shaft 110, the boundary between the inner region 112a and the outer region 112b is linear.

  As shown in FIG. 9 (d), the shaft 110 has a first peripheral wall portion 111 formed of the first material and a second peripheral wall portion 112 formed of a mixture of the first material and the second material. You may do it. Each of the first peripheral wall portion 111 and the second peripheral wall portion 112 has a semicircular cross section and forms half of the shaft 110.

(18) The cross-sectional shape of the shaft of the medical instrument to which the present invention is applied does not have to be circular, and may have a polygonal shape such as a square shape or a hexagonal shape, or other shapes.
[About other inventions extracted from the disclosure scope of this specification]

  Hereinafter, inventions that can be extracted in addition to the invention described in the means for solving the problems in the disclosure scope of the present specification will be described while showing effects and the like as necessary.

(Appendix 1)
A medical instrument inserted into the body,
A shaft having a curved portion;
In the curved portion, it has a corner inner portion including the corner innermost portion and a corner outer portion which is the corner outer side than the corner inner portion,
The curved portion includes a first material and a second material,
One material of the first material and the second material is a high yield elongation material having a higher yield elongation than the other material, and the other material is a low yield elongation material;
The ratio of the high yield elongation material to the sum of the high yield elongation material and the low yield elongation material with respect to the amount of constituent material is characterized in that the corner inner portion is larger than the corner outer portion. Medical instrument.

  When the shaft of the medical device has a curved portion, the shaft may be greatly deformed so that the curved portion is extended during use or manufacture of the medical device. At this time, tensile strain occurs in the corner inner portion of the curved portion, and compressive strain occurs in the outer corner portion. Further, the innermost portion of the corner inner portion is the portion where the tensile strain becomes the largest. Therefore, in the present invention, the ratio of the high yield elongation material to the total of the high yield elongation material and the low yield elongation material is larger in the corner inner portion than in the corner outer portion. For this reason, a corner inner part has yield yield higher than a corner outer part, and even if it is a case where a tensile strain arises, it can suppress that it deforms plastically and can improve resilience. Also, in general, a material with a high yield elongation is less rigid than a material with a low yield elongation. Therefore, the corner outer portion has higher rigidity than the corner inner portion, and as a result, a reduction in the rigidity of the shaft can be suppressed.

(Appendix 2)
The corner inner portion includes a higher yield elongation material than a low yield elongation material, and the corner outer portion includes a lower yield elongation material than a high yield elongation material. The medical instrument described in 1.

  In this case, the yield elongation of the inner corner portion is further increased, and the rigidity of the outer corner portion is further increased. Accordingly, it is possible to further suppress the reduction in the rigidity of the shaft while further improving the restoring property of the shaft.

  DESCRIPTION OF SYMBOLS 10 ... Guiding catheter as a medical instrument, 12, 52 ... Shaft, 24, 64 ... 2nd bending part, 31 ... Reinforcement layer, 32 ... Inner layer, 33 ... Outer layer as a surrounding wall, 34, 74, 81, DESCRIPTION OF SYMBOLS 111 ... 1st surrounding wall part, 34I, 75I ... Corner inner part, 35, 75, 82, 112 ... 2nd surrounding wall part, 50 ... Contrast catheter as medical instrument, 55, 80 ... Surrounding wall, 110 ... Shaft as surrounding wall .

Claims (5)

A medical instrument inserted into the body,
A shaft having a peripheral wall, the peripheral wall comprising:
A first peripheral wall portion formed of a first material having a first yield elongation and forming a part of the peripheral wall in the circumferential direction ;
A second peripheral wall that includes the first material and a second material having a second yield elongation different from the first yield elongation, and forms a remaining portion other than the first peripheral wall portion of the peripheral wall. has a part, the,
The second peripheral wall portion is
An inner region formed from a mixture of the first material and the second material;
A medical instrument comprising: an outer region formed from the second material . The shaft has a curved portion;
The corner innermost portion of the corner inner portion of the curved portion is formed by a peripheral wall portion having a high yield elongation of the first peripheral wall portion and the second peripheral wall portion. The medical device described.   The medical instrument according to claim 2, wherein the inner corner portion is configured not to yield in a state where the curved portion is deformed linearly.   Of the first peripheral wall portion and the second peripheral wall portion, the peripheral wall portion having a high yield elongation is a compression in which a compressive stress is generated in the bending portion when a load is applied to the bending portion to extend the bending portion. The medical instrument according to claim 2 or 3, wherein the medical instrument is arranged so as not to protrude into the region. The shaft, according to any one of claims 1-4, characterized in that it comprises an inner layer provided on the inside than the peripheral wall, and a reinforcing layer provided between the inner layer and the peripheral wall Medical instruments.

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