Guidewires

Abstract

This guide wire comprises a core shaft. A main body of the guide wire, which is a portion 350-750 mm from the tip of the core shaft, is made of nickel-titanium alloy, and the outer diameter of the main body is 0.58-0.73 mm.

Description

[Technical field]

[0001] The present invention relates to a guidewire. [Background technology]

[0002] A guidewire has been known as a medical device that is percutaneously inserted into a blood vessel to treat a stenosis that has occurred in the blood vessel. Regarding this guidewire, Patent Document 1 describes a guidewire used for treating blood vessels in the lower limbs. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication 2016-174645 Summary of the Invention [Problem to be solved by the invention]

[0004] A method called the crossover method is adopted as a method for treating a stenosis in a blood vessel of a lower limb using a guidewire. FIG. 26 is an explanatory diagram illustrating an example of a blood vessel of a lower limb of a human body. FIG. 27 is an explanatory diagram illustrating an example of an enlarged X region in FIG. 26. The crossover method is a method in which a guidewire 1 is inserted into a blood vessel from a puncture portion 101 near the thigh of a leg other than the leg having the stenosis Le, passes through a common iliac artery (hereinafter referred to as CIA) and advances to the leg having the stenosis Le, and reaches the stenosis Le. FIG. 26 illustrates a state in which the guidewire 1 is inserted into a blood vessel of a lower limb of a human body. Here, it is assumed that a stenosis Le occurs in an anterior tibial artery (hereinafter referred to as ATA) included in a region below the knee (hereinafter referred to as BK region). The guidewire 1 is first percutaneously inserted into a blood vessel in the body from a puncture portion 101 near the thigh of a leg other than the leg having the stenosis Le. The guidewire 1 advances through the CIA toward the abdominal aorta (hereinafter, AA), passes through the curved portion 100 of the CIA, and further advances through the CIA toward the stenosis Le. The guidewire 1 passes through the external iliac artery (hereinafter, EIA), the common femoral artery (hereinafter, CFA), the superficial femoral artery (hereinafter, SFA), and the popliteal artery (hereinafter, Pop.A), and reaches the anterior tibial artery (ATA). The guidewire 1 is placed near the stenosis Le, and a combination device such as a catheter is inserted into the blood vessel along the guidewire 1, and the stenosis Le is treated. Thus, in the crossover method, the guidewire passes through the CIA, EIA, and CFA, which are relatively curved even in the blood vessels of the lower limbs, so there is still room for improvement in the performance (torque transmission performance) of efficiently transmitting the operation of rotating the guidewire by the operator to the tip of the guidewire. There was also room for improvement in the performance (delivery performance) of passing concomitant instruments such as catheters inserted into blood vessels along guidewires through the CIA, which has a particularly large degree of curvature.

[0005] The present invention has been made to solve the above-mentioned problems, and has an object to provide a guidewire used for treating stenosis in lower limb blood vessels, which has excellent both torque transmission performance and delivery performance during treatment using the crossover method. [Means for solving the problem]

[0006] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized in the following forms.

[0007] (1) According to one embodiment of the present invention, there is provided a guidewire comprising a core shaft, a main body portion of the core shaft located 350 mm or more and 750 mm or less from a tip thereof made of a nickel-titanium alloy, and an outer diameter of the main body portion being 0.58 mm or more and 0.73 mm or less.

[0008] According to this configuration, the main body, which is a portion 350 mm or more and 750 mm or less from the tip of the core shaft, is made of nickel-titanium alloy, and has an outer diameter of 0.58 mm or more and 0.73 mm or less, so that a guidewire excellent in both torque transmission performance and delivery performance during treatment by the crossover method can be provided. Specifically, since the main body is made of nickel-titanium alloy, even when the main body passes through the CIA, EIA, and CFA, which have a large degree of curvature, by the crossover method, deterioration of operability due to deformation of the core shaft can be reduced. In addition, since the outer diameter of the main body is 0.58 mm or more, by arranging the main body near the CIA, a combined instrument such as a catheter can be easily advanced from one leg to the other leg along the guidewire. In addition, since the main body is 0.73 mm or less, by arranging the main body near the CIA, the operator's rotation operation can be efficiently transmitted to the tip of the guidewire. In addition, because the main body is located in the range of 350 mm to 750 mm from the tip of the core shaft, it is possible to position the main body near the CIA regardless of the length of the patient's blood vessels, thereby improving the torque transmission performance and delivery performance of the guidewire for a greater number of patients.

[0009] (2) In the guidewire of the above aspect, the core shaft may have a main body portion with an outer diameter of 0.71 mm or less.

[0010] According to this configuration, since the outer diameter of the main body portion, which is a portion 350 mm or more and 750 mm or less from the tip of the core shaft, is 0.71 mm or less, it is possible to further improve the torque transmission performance during treatment by the crossover method.

[0011] Note that the present invention can be realized in various aspects, for example, in the form of a guide wire, a method for manufacturing a guide wire, a method for manufacturing a catheter, an endoscope, a dilator, and the like.

Brief Description of the Drawings

[0012] [Figure 1] It is an explanatory diagram illustrating the overall configuration of the guide wire according to the first embodiment. [Diagram 2] It is an explanatory diagram illustrating the overall longitudinal section of the guide wire according to the first embodiment. [Diagram 3] It is an explanatory diagram illustrating the A1-A1 cross section of the guide wire according to the first embodiment. [Figure 4] It is an explanatory diagram illustrating the B1-B1 cross section of the guide wire according to the first embodiment. [Diagram 5] It is an explanatory diagram illustrating the C1-C1 cross section of the guide wire according to the first embodiment. [Figure 6] It is a diagram showing the test results of the torque transmission performance test. [Figure 7] It is an explanatory diagram showing the test method of the torque transmission performance test. [Figure 8] It is a diagram showing the test results of the delivery performance test. [Figure 9] It is an explanatory diagram showing the test method of the delivery performance test. [Figure 10] It is an explanatory diagram showing an example where the delivery performance is good. [Figure 11] It is an explanatory diagram showing an example where the delivery performance is not good. [Figure 12] It is a diagram showing the measurement results of the bending load of the catheter. [Figure 13]FIG. 1 is a diagram illustrating a state in which a guidewire is placed in a blood vessel in a lower limb of a human body. [Figure 14] FIG. 11 is an explanatory view illustrating an entire longitudinal section of a guidewire according to a second embodiment. [Figure 15] FIG. 11 is an explanatory view illustrating the A2-A2 cross section of the guidewire according to the second embodiment. [Figure 16] FIG. 11 is an explanatory view illustrating a B2-B2 cross section of the guidewire according to the second embodiment. [Figure 17] FIG. 11 is an explanatory view illustrating a C2-C2 cross section of the guide wire according to the second embodiment. [Figure 18] FIG. 11 is an explanatory view illustrating an entire longitudinal section of a guidewire according to a third embodiment. [Figure 19] FIG. 11 is an explanatory view illustrating the A3-A3 cross section of the guidewire according to the third embodiment. [Figure 20] FIG. 11 is an explanatory view illustrating a B3-B3 cross section of the guidewire according to the third embodiment. [Figure 21] FIG. 11 is an explanatory view illustrating a C3-C3 cross section of the guide wire according to the third embodiment. [Figure 22] FIG. 13 is an explanatory view illustrating an example of an entire longitudinal section of a guidewire according to a fourth embodiment. [Figure 23] FIG. 13 is an explanatory view illustrating the A4-A4 cross section of the guidewire according to the fourth embodiment. [Figure 24] FIG. 13 is an explanatory view illustrating a B4-B4 cross section of the guide wire according to the fourth embodiment. [Diagram 25] FIG. 13 is an explanatory view illustrating a C4-C4 cross section of the guide wire according to the fourth embodiment. [Figure 26] FIG. 1 is an explanatory diagram illustrating blood vessels in the lower limbs of a human body. [Figure 27] 27 is an explanatory diagram illustrating an enlarged example of an X region in FIG. 26. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] A guidewire is a medical device that is inserted into blood vessels or digestive organs by doctors and other medical professionals for use in treatment or examination.

[0014] In the following, the left side in each of Figs. 1, 2, 14, 18, and 22 is referred to as the "tip side" of the guidewire and each component of the guidewire of the present invention, and the right side is referred to as the "rear end side" of the guidewire and each component. The tip side of the guidewire is the side that is inserted into the body first when the guidewire is inserted into the body, and the rear end side of the guidewire is the side (proximal side) that is operated by a technician such as a doctor. In addition, the end portion located on the tip side of the guidewire and each component of the guidewire is described as the "tip", and the part including the "tip" and extending from the tip to the middle toward the rear end side is described as the "tip portion". Similarly, the end portion located on the rear end side of the guidewire and each component of the guidewire is described as the "rear end", and the part including the "rear end" and extending from the rear end to the middle toward the tip side is described as the "rear end portion".

[0015] 1, 2, 14, 18, and 22, the left-right direction is referred to as the long axis direction of the guidewire and each of its components. The direction perpendicular to the long axis direction is referred to as the radial direction of the guidewire and each of its components.

[0016] Each of Figs. 1 to 27 includes portions in which the relative ratios of the sizes of the guidewire and each of the components of the guidewire are depicted in different relative ratios than in reality, for the sake of convenience of explanation.

[0017] In the present application, the outer diameter of the core shaft refers to the average value of all the measured outer diameters. In addition, in the present application, the outer diameter of the core shaft being substantially constant means that the maximum value of the outer diameters of the core shaft is 1.05 times or less than the minimum value. In the present application, the outer diameter of the core shaft is measured by a non-contact outer diameter measuring device using a laser beam, and is measured at intervals of 0.15 mm or less in the longitudinal direction of the core shaft.

[0018] First Embodiment Fig. 1 is an explanatory diagram illustrating the overall configuration of a guidewire 1A of a first embodiment. Fig. 1 illustrates the inside of a resin film 40 through the resin film 40. Fig. 2 is an explanatory diagram illustrating an overall vertical cross section of the guidewire 1A of the first embodiment.

[0019] The guidewire 1A of the first embodiment is a medical device that is percutaneously inserted into a blood vessel to treat a stenosis occurring in a blood vessel of a lower limb. The guidewire 1A has a core shaft 10A, a coil 20 that covers a part of the outer periphery of the core shaft 10A, and a resin film 40. The tip end of the coil 20 and the tip end of the core shaft 10A are fixed by a tip side fixing part 30. In addition, the rear end of the coil 20 and the core shaft 10A are fixed by a rear end side fixing part 31.

[0020] The core shaft 10A is a member with a total length of about 2000 mm to about 4000 mm. The cross section of the core shaft 10A is circular, and its maximum outer diameter is 0.58 mm or more and about 1.0 mm or less. The core shaft 10A has a small diameter portion 11, a main body portion 14A, and a large diameter portion 15 from the tip side to the rear end side. The small diameter portion 11 is a portion having an outer diameter smaller than the outer diameter Db1 of the main body portion 14A. The small diameter portion 11 has a tip side straight portion 12 and a tip side tapered portion 13. The tip side straight portion 12 constitutes the tip of the core shaft 10A, and its outer diameter Da1 (FIG. 3) is approximately constant along the longitudinal direction of the core shaft 10A. The tip side tapered portion 13 is provided between the tip side straight portion 12 and the main body portion 14A, and has a tapered shape in which the outer diameter gradually increases toward the rear end side of the core shaft 10A. A part of the outer circumference of the small diameter portion 11 is covered by the coil 20. The part of the small diameter portion 11 covered by the coil 20 is a reinforcing portion. The main body portion 14A is provided between the small diameter portion 11 and the large diameter portion 15 of the core shaft 10A, and its outer diameter Db1 (FIG. 4) is substantially constant along the longitudinal direction of the core shaft 10A. The large diameter portion 15 is a portion having an outer diameter larger than the outer diameter Db1 of the main body portion 14A. The large diameter portion 15 has a rear end side tapered portion 16 and a rear end side straight portion 17A. The rear end side tapered portion 16 is provided between the main body portion 14A and the rear end side straight portion 17A, and has a tapered shape in which the outer diameter gradually increases toward the rear end side of the core shaft 10A. The rear end side straight portion 17A constitutes the rear end of the core shaft 10A, and its outer diameter Dc1 (FIG. 5) is substantially constant along the longitudinal direction of the core shaft 10A. The large diameter portion 15 functions as a high rigidity portion having a higher torsional rigidity than the main body portion 14A.

[0021] In the guidewire 1A of the first embodiment, La1 is the length of the small diameter portion 11 in the major axis direction. Lb1 is the length of the main body portion 14A in the major axis direction. Lc1 is the length of the large diameter portion 15 in the major axis direction.

[0022] The main body 14A is made of a nickel-titanium alloy. The nickel-titanium alloy is an alloy whose composition is mainly composed of nickel and titanium. For example, the nickel-titanium alloy is an alloy containing about 54% to about 57.0 wt% nickel and the remaining part is titanium. The nickel-titanium alloy may contain inclusions such as carbon, cobalt, copper, and chromium. The part of the core shaft 10A other than the main body 14A may be made of a material such as a nickel-titanium alloy, a stainless steel alloy (SUS302, SUS304, SUS316, etc.), a piano wire, a nickel-chromium alloy, a cobalt alloy, or tungsten. In this embodiment, the main body 14A and the part of the core shaft 10A other than the main body 14A are made of the same material, that is, a nickel-titanium alloy.

[0023] The coil 20 is an example of a reinforcing body described in the claims of the present application. The coil 20 is a tubular member that covers a part of the outer periphery of the small diameter portion 11. The coil 20 is formed by winding a thin metal wire in a spiral shape. The coil 20 can be formed from materials such as nickel-titanium alloy, stainless steel alloy (SUS302, SUS304, SUS316, etc.), piano wire, nickel-chromium alloy, cobalt alloy, tungsten, etc.

[0024] The tip end of the core shaft 10A and the tip end of the coil 20 are fixed by a tip side fixing part 30. The rear end of the core shaft 10A and the rear end of the coil 20 are fixed by a rear end side fixing part 31. The tip end of the tip side fixing part 30 is formed to be semispherical. The tip side fixing part 30 and the rear end side fixing part 31 are formed by, for example, a metal solder such as silver solder or gold solder, or an adhesive using an epoxy resin.

[0025] The resin film 40 is a thin film member that covers the entire circumference of the guide wire 1 A. The resin film 40 is formed from, for example, polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol, polyacrylamide, polyacrylic acid, sodium polyacrylate, polyurethane, polytetrafluoroethylene, perfluoroalkoxyalkane, poly(2-hydroxyethyl methacrylate), maleic anhydride copolymer, ethylene-vinyl alcohol copolymer, 2-methacryloyloxyethyl phosphorylcholine or its copolymer, (2-hydroxyethyl methacrylate)-styrene block copolymer, various synthetic polypeptides, collagen, hyaluronic acid, cellulose-based polymer, and mixtures thereof.

[0026] Fig. 3 is an explanatory diagram illustrating an A1-A1 cross section of the guidewire 1A of the first embodiment. In Fig. 3, a cross section of the tip-side straight portion 12 is shown. Fig. 4 is an explanatory diagram illustrating a B1-B1 cross section of the guidewire 1A of the first embodiment. In Fig. 4, a cross section of the main body portion 14A is shown. Fig. 5 is an explanatory diagram illustrating a C1-C1 cross section of the guidewire 1A of the first embodiment. In Fig. 5, a cross section of the rear-end straight portion 17A is shown.

[0027] The cross section of the tip side straight portion 12 is a circle with an outer diameter Da1. The tip side straight portion 12 is the thinnest portion of the core shaft 10A. The outer diameter Da1 of the tip side straight portion 12 is smaller than the outer diameter Db1 of the main body portion 14A. The cross section of the main body portion 14A is a circle with an outer diameter Db1. The outer diameter Db1 of the main body portion 14A is larger than the outer diameter Da1 of the tip side straight portion 12 and smaller than the outer diameter Dc1 of the rear end side straight portion 17A. The cross section of the rear end side straight portion 17A is a circle with an outer diameter Dc1. The rear end side straight portion 17A is the thickest portion of the core shaft 10A. The outer diameter Dc1 of the rear end side straight portion 17A is larger than the outer diameter Db1 of the main body portion 14A.

[0028] As described later, in consideration of the torque transmission performance and delivery performance of the guidewire used in the crossover method, the outer diameter Db1 of the main body 14A is set to 0.58 mm or more and 0.73 mm or less. More preferably, the outer diameter Db1 of the main body 14A is set to 0.58 mm or more and 0.71 mm or less.

[0029] <Torque transmission performance test> FIG. 6 is a diagram showing the test results of the torque transmission performance test. In the torque transmission performance test, as shown in FIG. 6, five types of guidewires (samples 1 to 5) having different outer diameters Db1 of the main body were prepared. As shown in FIG. 6, the larger the sample number, the larger the outer diameter Db1 of the main body 14A. The test method of the torque transmission performance test will be described later with reference to FIG. 7. The "input angle" in FIG. 6 is the evaluation value of each sample obtained by the torque transmission performance test, and the "test result" is the result determined from the evaluation value of the "input angle". Here, for reasons described later, samples with an input angle of 315 degrees or less were designated "A1", samples with an input angle of more than 315 degrees and less than 360 degrees were designated "A2", and samples with an input angle of more than 360 degrees were designated "B".

[0030] FIG. 7 is an explanatory diagram showing a test method for the torque transmission performance test. The torque transmission performance test blood vessel model T4 is provided with a simulated blood vessel T5 that imitates the CIA and blood vessels in the vicinity thereof. The torque transmission performance test is performed using the torque transmission performance test blood vessel model T4 in the following procedure. First, the catheter T3 is placed so as to cover the entire length of the simulated blood vessel T5. Next, one of the guide wires 1S of the samples 1 to 5 is inserted into the catheter T3, and the main body is placed so as to cover the entire length of the torque transmission performance test model T4. Next, the rear end of the guide wire 1S is connected to the guide wire rotation unit T1, and the guide wire 1S is rotated in the direction of the rotation direction T2 in FIG. 7 by the rotation unit T1. The measurement marker T6 attached to the tip of the guide wire 1S is photographed by the camera T7, and the input angle of the rotation unit T1 when the rotation angle becomes 180 degrees is recorded. The "input angle" column in FIG. 6 shows the input angle of the rotation unit T1 when the rotation angle of the measurement marker T6 becomes 180 degrees for each of the samples 1 to 5. The rotation angle of the measurement marker T6 corresponds to the rotation angle of the tip of the guidewire 1S. The input angle of the rotation unit T1 corresponds to the rotation angle when the operator rotates the rear end of the guidewire 1S.

[0031] As for the test results of this test, samples A1 and A2 were judged to have good torque transmission performance. In particular, sample A1 was judged to have better test results. This standard was determined in consideration of the fact that when an operator rotates the tip of a guidewire to determine its direction of travel at a branching point of a blood vessel, etc., a torque transmission performance of the extent to which the tip of the guidewire rotates half a turn with one finger operation of the operator (an operation to rotate the rear end of the guidewire about one turn) is required. A sample showing better torque transmission performance, in which the operator can rotate the tip of the guidewire half a turn without rotating the rear end of the guidewire one turn, was designated A1, and a sample that can rotate the tip of the guidewire half a turn with at least one turn or less was designated A2. From the test results, it can be determined that samples 3 and 4 have good torque transmission performance, and samples 1 and 2 have better torque transmission performance. From this, it can be determined that when the outer diameter Db1 of the main body 14A is 0.73 mm or less, the torque transmission performance is good, and when the outer diameter Db1 of the main body 14A is 0.71 mm or less, the torque transmission performance is even better.

[0032] <Delivery performance test> FIG. 8 is a diagram showing the test results of the delivery performance test. In the delivery performance test, as shown in FIG. 8, five types of guidewires (samples 6 to 10) with different outer diameters Db1 of the main body were prepared. As shown in FIG. 8, the larger the sample number, the larger the outer diameter Db1 of the main body 14A. The test method and evaluation method of the delivery performance test will be described later with reference to FIG. 9 to FIG. 11. The "Test Results" in FIG. 8 are the results of evaluation using the evaluation method described later. Here, the sample that was in the state shown in FIG. 10 during delivery was designated "A," and the sample that was in the state shown in FIG. 11 was designated "B." The sample with the test result A indicates that the delivery performance was good. The sample with the test result B indicates that the delivery performance was not good.

[0033] Fig. 9 is an explanatory diagram showing the test method of the delivery performance test. Fig. 10 is an explanatory diagram showing an example where the delivery performance is good in the delivery performance test. Fig. 11 is an explanatory diagram showing an example where the delivery performance is not good in the delivery performance test. Fig. 12 shows the measurement results of the bending load of the catheter used in the delivery performance test.

[0034] The blood vessel model T8 for delivery performance test is provided with a simulated blood vessel T9 that mimics the shape of the CIA and blood vessels near the CIA. The delivery performance test is performed according to the following procedure. First, a guidewire 1S, which is one of the samples 6 to 10, is inserted into the simulated blood vessel T9 from an opening T11 provided at the end of the simulated blood vessel T9, and is indwelled with its main body disposed at a curved portion 100 of the CIA. Next, a catheter T10 is inserted into the simulated blood vessel T9 from the opening T11 along the guidewire 1A. In this test, the catheter T10 used was DESTINATION (registered trademark) by Terumo Corporation, which is a catheter commonly used in lower limb vascular treatment. The catheter T10 has an inner diameter of about 2.24 mm and an outer diameter of about 2.79 mm. FIG. 12 shows the bending load corresponding to the distance from the tip of the catheter T10. Next, the catheter T10 is advanced beyond the curved portion 100 of the CIA toward the EIA. At this time, as shown in Fig. 10, the position of the main body of the indwelling guidewire 1A did not change significantly when the catheter T10 was moved, and the catheter T10 could be advanced beyond the curved part 100 of the CIA. In contrast, as shown in Fig. 11, the position of the main body of the indwelling guidewire 1S changed significantly when attempting to advance the catheter T10 toward the EIA, and the main body and the catheter T10 were pushed out toward the AA. In such a case, the delivery performance of the sample was determined to be poor.

[0035] In the test results shown in Figure 8, the delivery performance of sample 10, in which the catheter T10 could be advanced beyond the curved part 100 of the CIA, was judged to be good, whereas the delivery performance of samples 6 to 9, in which the catheter T10 could not be advanced beyond the curved part 100 of the CIA, was judged to be poor. From this, it can be judged that the delivery performance is good when the outer diameter Db1 of the main body part 14A is 0.58 mm or more.

[0036] <Evaluation of the position and range of the main body> FIG. 13 is an explanatory diagram illustrating a state in which the guidewire 1A is placed in a lower limb blood vessel of a human body by the crossover method. Here, the position and range of the main body part, which has an outer diameter Db1 obtained in the torque transmission performance test and the delivery performance test described above, is considered so that the main body part is located at a curved part of the lower limb blood vessel when the guidewire is placed in the lower limb blood vessel by the crossover method. As shown in FIG. 13, the lower limb blood vessels are formed in the following order from the abdomen to the toes: AA (abdominal aorta), CIA (common iliac artery), EIA (external iliac artery), and CFA (common femoral artery). The CFA branches into SFA (superficial femoral artery) and DFA (deep femoral artery), the SFA connects to Pop.A (popliteal artery), and Pop.A branches into ATA (anterior tibial artery), PTA (posterior tibial artery), and Pero.A (peroneal artery). The BK region in FIG. 13 indicates the lower limb blood vessels including the ATA, PTA, and Pero.A. In the blood vessels of the lower limbs, blood vessels with a large degree of curvature, such as the curved portion 100 of the CIA, tend to be more common in the CIA, EIA, and CFA. The X region shown in FIG. 13 indicates a region including blood vessels with a large degree of curvature. L1 shown in FIG. 13 is the length from the end of the AA to the end of the CFA. According to CT scan data obtained from a patient, L1 is about 150 mm. In addition, since the puncture portion 101, which is the position where the guide wire 1A is inserted in the crossover method, is often near the end of the CFA, the distance from the puncture portion 101 to the end of the AA is approximately the same as L1. Thus, the length from the puncture portion 101 to the end of the CFA of the other leg is about 300 mm. Furthermore, L2 is the length from the end of the CFA to the end of Pop.A. According to CT scan data obtained from a patient, L2 is about 350 mm to about 450 mm. For example, when a stenosis Le occurs in the ATA, PTA, or Pero.A and the tip of the guidewire 1A is placed in the blood vessel, if the length of L2 is about 350 mm, then the range of the core shaft 10A of the guidewire 1A from the tip to about 350 mm or more and about 650 mm or less is placed in the X region. Also, if the length of L2 is about 450 mm, then the range of the core shaft 10 of the guidewire 1A from the tip to about 450 mm or more and about 750 mm or less is placed in the X region.For this reason, when treating a stenosis Le occurring in the BK region using the crossover method, the portion of the core shaft 10A of the guidewire 1A that is at least approximately 350 mm from the tip and at least approximately 750 mm therefrom is likely to be positioned in the X region.

[0037] The portion of the core shaft 10A that is placed in the X region varies depending on the location of the stenosis Le and the position of the puncture portion 101. The inventors specified a position in the human body where the puncture portion 101 can be easily set, and performed the above setting so that the main body portion 14A is located in the X region even when the guidewire is placed so that the tip of the guidewire reaches the BK region where the stenosis Le is likely to occur and where torque transmission and deliverability are most necessary.

[0038] As described above, the guidewire 1A of this embodiment has the main body 14A as a portion of the core shaft 10A that is 350 mm or more and 750 mm or more from the tip. With this configuration, when a stenosis Le occurring in the BK region or the like is treated by the crossover method, the main body 14A is more likely to be disposed in the X region regardless of the length of L2. The outer diameter Db1 of the main body 14A is 0.73 mm or less. This reduces the amount of strain caused by bending deformation when the main body 14A is inserted into a curved portion of a blood vessel, and also reduces the contact resistance that the main body 14A receives from the inner wall of the blood vessel, so that the guidewire 1A can exhibit good torque transmission performance even in the crossover method. Alternatively, the outer diameter Db1 of the main body 14A may be 0.71 mm or less. This further reduces the amount of strain caused by bending deformation when main body portion 14A is inserted into a curved portion of a blood vessel, and also further reduces the contact resistance that main body portion 14A receives from the inner wall of the blood vessel, allowing guidewire 1A to exhibit better torque transmission performance even in the crossover method. Also, since the outer diameter Db1 of main body portion 14A is 0.58 mm or more, guidewire 1A can exhibit good delivery performance even in the crossover method.

[0039] The main body 14A is made of a nickel-titanium alloy, which reduces deterioration of operability due to deformation of the core shaft 10A even when the main body is inserted into a CIA, EIA, or CFA that has a relatively large degree of curvature.

[0040] In the guidewire 1A of the first embodiment, the outer diameter Db1 of the main body 14A is substantially constant along the longitudinal direction. This allows for good torque transmission and delivery performance to be exhibited regardless of the relative positional relationship between the main body 14A and the blood vessel, as compared with a case in which the outer diameter Db1 of the main body 14A is not substantially constant, such as a tapered shape in which the outer diameter Db1 of the main body 14A gradually increases along the longitudinal direction, or a stepped shape in which the outer diameter Db1 of the main body 14A increases at regular intervals along the longitudinal direction. In other words, good torque transmission and delivery performance can be exhibited in both cases, whether the distal end side or the proximal end side of the main body 14A is disposed in the CIA, EIA, or CFA, which have a relatively large degree of curvature.

[0041] The guidewire 1A of the first embodiment has a resin film 40. This can reduce the sliding resistance between the outer circumferential surface of the guidewire 1A and the inside of a blood vessel, improving the slipperiness of the guidewire 1A inside the blood vessel.

[0042] The guidewire 1A of the first embodiment has a coil 20. This allows the strength of the reinforcing portion of the guidewire 1A that is inserted into a blood vessel with a smaller diameter at the more distal end to be improved by the reinforcing body. In the first embodiment, the reinforcing portion is a portion of the small diameter portion 11 whose outer periphery is covered by the coil 20. Also, the guidewire 1A has the small diameter portion 11, which allows the flexibility of the tip side of the guidewire 1A to be further improved. Also, the guidewire 1A has a tip side tapered portion 13. This allows the bending rigidity of the core shaft 10A to be gradually increased from the tip side straight portion 11 toward the main body portion 14A, and the possibility of the core shaft 10A being kinked due to stress concentration in the portion between the tip side straight portion 12 and the main body portion 14A can be reduced. Also, the guidewire 1A has a large diameter portion 15. This allows the torsional rigidity of the rear end portion of the guidewire 1A to be higher, allowing the torque transmission performance to be further improved. Also, the guidewire 1A has a rear end side tapered portion 16. This allows the bending rigidity of core shaft 10A to be gradually increased from main body portion 14A to rear end straight portion 17A, reducing the possibility of stress concentrating in the area between main body portion 14A and rear end straight portion 17A, causing core shaft 10A to kink.

[0043] <Second embodiment> Fig. 14 is an explanatory diagram illustrating an overall longitudinal section of the guidewire 1B of the second embodiment. Fig. 15 is an explanatory diagram illustrating an A2-A2 section of the guidewire 1B of the second embodiment. Fig. 16 is an explanatory diagram illustrating a B2-B2 section of the guidewire 1B of the second embodiment. Fig. 17 is an explanatory diagram illustrating a C2-C2 section of the guidewire 1B of the second embodiment.

[0044] The guide wire 1B of the second embodiment is different from the guide wire 1A of the first embodiment in that it does not have a large-diameter portion 15 (Fig. 2). The portions of the guide wire 1B of the second embodiment other than the large-diameter portion 15 are common to the guide wire 1A of the first embodiment. The guide wire 1B has a core shaft 10B having a rear-end-side straight portion 17B. The rear-end-side straight portion 17B is on the rear-end side of the main body portion 14A and constitutes the rear end portion of the core shaft 10B. Lc2 is the length of the rear-end-side straight portion 17B in the major axis direction. The outer diameter Dc2 of the rear-end-side straight portion 17B is substantially the same as the outer diameter Db1 of the main body portion 14A.

[0045] Also, the guide wire 1B of the second embodiment described above can exhibit the same effects as the guide wire 1A of the first embodiment. Since the outer diameter Dc2 of the rear-end-side straight portion 17B is substantially the same as the outer diameter Db1 of the main body portion 14A, for example, even when the CIAs, EIAs, and CFAs with a large degree of curvature are longer than expected and the core shaft 10B on the rear-end side of the main body portion 14A is disposed within those blood vessels, good torque transmission performance and delivery performance can be exhibited.

[0046] <Third Embodiment> FIG. 18 is an explanatory diagram illustrating an overall longitudinal section of a guide wire 1C according to a third embodiment. FIG. 19 is an explanatory diagram illustrating a cross section taken along line A3 - A3 of the guide wire 1C according to the third embodiment. FIG. 20 is an explanatory diagram illustrating a cross section taken along line B3 - B3 of the guide wire 1C according to the third embodiment. FIG. 21 is an explanatory diagram illustrating a cross section taken along line C3 - C3 of the guide wire 1C according to the third embodiment.

[0047] The guidewire 1A of the first embodiment and the guidewire 1C of the third embodiment are different in that the rear end side straight portion 17C of the guidewire 1C is formed of a different material having a higher torsional rigidity than the main body portion 14A. The guidewire 1C of the third embodiment has a portion other than the rear end side straight portion 17C in common with the guidewire 1A of the first embodiment. The rear end side straight portion 17C is depicted in FIG. 18 with hatching in a pattern different from that of the main body portion 14A. The guidewire 1C has a core shaft 10C having a rear end side straight portion 17C. The rear end side straight portion 17C is a portion that is on the rear end side of the main body portion 14A and constitutes the rear end portion of the core shaft 10C. The outer diameter Dc3 of the rear end side straight portion 17C is approximately the same as the outer diameter Db1 of the main body portion 14A. Lc3 is the length in the major axis direction of the rear end side straight portion 17C. The rear straight portion 17C is made of a material having a higher modulus of lateral elasticity than the material of the main body portion 14A. The rear straight portion 17C can be made of a material such as a stainless steel alloy (SUS302, SUS304, SUS316, etc.), a piano wire, a nickel-chromium alloy, a cobalt alloy, or tungsten. The rear end of the main body portion 14A and the tip of the rear straight portion 17C are joined by a method such as soldering, adhesive, or welding.

[0048] The guidewire 1C of the third embodiment described above can also achieve the same effects as the guidewire 1A of the first embodiment. In addition, since the modulus of transverse elasticity of the material of the rear end straight portion 17C is higher than the modulus of transverse elasticity of the material of the main body portion 14A, the torsional rigidity of the rear end portion of the core shaft 10C is higher, and better torque transmission performance can be achieved.

[0049] <Fourth embodiment> Fig. 22 is an explanatory diagram illustrating an overall longitudinal section of the guidewire 1D of the fourth embodiment. Fig. 23 is an explanatory diagram illustrating an A4-A4 section of the guidewire 1D of the fourth embodiment. Fig. 24 is an explanatory diagram illustrating a B4-B4 section of the guidewire 1D of the fourth embodiment. Fig. 25 is an explanatory diagram illustrating a C4-C4 section of the guidewire 1D of the fourth embodiment.

[0050] The guidewire 1A of the first embodiment and the guidewire 1D of the fourth embodiment differ in that the main body 14D of the guidewire 1D has a tapered shape in which the outer diameter Db4 gradually increases toward the rear end side of the core shaft 10D. The portions of the guidewire 1D of the fourth embodiment other than the main body 14D are common to the guidewire 1A of the first embodiment. The guidewire 1D has a core shaft 10D having a main body 14D. The outer diameter Db4 of the main body 14D gradually increases toward the rear end side of the core shaft 10D. Lb4 is the length in the longitudinal direction of the main body 14D.

[0051] The guidewire 1D of the fourth embodiment described above can also achieve the same effects as the guidewire 1A of the first embodiment. Since the main body portion 14D of the guidewire 1D has a tapered shape, the bending rigidity of the core shaft 10D can be gradually increased from the small diameter portion 11 to the large diameter portion 15. This can reduce the possibility that the main body portion 14D will kink due to stress concentration on the main body portion 14D.

[0052] <Variation 1> The guidewire 1A of the first embodiment has been described as having a straight tip straight section 12, a main body section 14A, and a straight rear section 17A, and a tapered tip section 13 and a tapered rear section 16 that increase in diameter from the tip to the base. However, the outer diameter of each section of the core shaft may be a straight shape that is substantially constant in the longitudinal direction, or may be a tapered shape that gradually increases or decreases toward the rear end of the core shaft. Alternatively, the outer diameter of each section of the core shaft may be a stepped shape that increases or decreases at intervals of a certain length in the longitudinal direction of the core shaft.

[0053] <Variation 2> The cross-section of the core shaft 10 of the guide wire 1A of the first embodiment was assumed to be circular. However, the cross-section of the core shaft 10 does not have to be circular, and may be a rectangular shape such as a square or a rectangle, or a triangle. In particular, when the cross-section of the straight portion 12 on the tip side of the guide wire 1A is anisotropic in a direction that is easily deformed like a rectangle, it becomes easier for the operator to shape the tip of the guide wire.

[0054] <Modification 3> The guide wire 1A of the first embodiment was assumed to have a greater torsional rigidity on the rear end side than on the tip side. However, the core shaft may be configured such that the torsional rigidity on the tip side is greater in the major axis direction. For example, the torsional rigidity of the small diameter portion may be higher than the torsional rigidity of the main body portion.

[0055] <Modification 4> The resin film 40 of the first embodiment was composed of a single type and had unchanging characteristics. However, the resin film covering the outer periphery of the core shaft may have characteristics that change in the major axis direction of the core shaft. For example, the main body portion and the large diameter portion may be covered with a hydrophobic resin film, or only the large diameter portion may be covered with a hydrophobic resin film. A guide wire with the large diameter portion covered with a hydrophobic resin film can have a frictional force that allows the operator to easily grip the guide wire while having the sliding performance of the guide wire. Also, the entire main body portion may be covered with a resin film having the same characteristics, or different portions of the main body portion may be covered with a plurality of resin films having different characteristics. Further, part or all of the core shaft may be covered such that a plurality of resins are layered. For example, the outer periphery of the coil and the main body portion may be covered with a resin film containing urethane, and further, the outer periphery of the resin film containing urethane may be covered with a hydrophilic resin film.

[0056] <Modification 5> The reinforcing body of the first embodiment was formed by spirally winding a thin metal wire. However, the reinforcing body may be a hollow coil formed by twisting a plurality of metal wires. Also, the guide wire does not have to have a reinforcing body. When there is no reinforcing body, the outer periphery of the tip portion of the core shaft may be covered with a resin film. [Explanation of symbols]

[0057] 1, 1A, 1B, 1C, 1D, 1S...Guidewire 10A, 10B, 10C, 10D...Core shaft 11…Small diameter part 12...Straight section at tip 13...Tip side tapered section 14A, 14D…Main body 15…Large diameter section 16…Tapered rear end 17A, 17B, 17C...Rear end straight section 20…Coil 30…Tip side fixing part 31…Rear end side fixing part 40…Resin film 100…CIA curved section 101...Puncture part La1: Length of small diameter part of core shaft Lb1, Lb4: Length of the core shaft body Lc1, Lc2, Lc3...Length of large diameter part of core shaft Da1: Outer diameter of the straight part at the tip Db1, Db4: Outer diameter of main body Dc1, Dc2, Dc3...Outer diameter of rear end straight section AA…abdominal aorta CIA…Common iliac artery EIA…external iliac artery CFA…Common femoral artery SFA…Superficial femoral artery DFA…Deep femoral artery Pop.A…popliteal artery ATA…Anterior tibial artery PTA…posterior tibial artery Pero.A…peroneal artery BK…Below the knee area Le…vascular stenosis L1: Length from AA bend to CFA end L2: Length from CFA end to Pop.A end T1…Guidewire rotation unit T2: Guidewire rotation direction T3, T10…catheter T4…Blood vessel model for torque performance testing T5…Simulated blood vessel T6…Measurement marker T7…camera T8…Blood vessel model for delivery performance testing T9…Simulated blood vessel T11, T12...opening

Claims

1. A guidewire comprising: A core shaft is provided. The core shaft includes: A main body portion that is a portion that is 350 mm or more and 750 mm or less from the tip; a large diameter portion provided on a rear end side of the main body portion and having an outer diameter larger than an outer diameter of the main body portion; The main body is made of a nickel-titanium alloy, and the outer diameter of the main body is 0.58 mm or more and 0.73 mm or less. Guidewire.

2. 2. The guidewire of claim 1, The core shaft has an outer diameter of the main body portion of 0.58 mm or more and 0.71 mm or less. Guidewire.

3. The guidewire according to claim 1 or 2, The core shaft is provided on a tip side of the main body portion and has a small diameter portion whose outer diameter is smaller than the outer diameter of the main body portion. Guidewire.

4. 4. The guidewire of claim 3, The small diameter portion includes a first straight portion having a substantially constant outer diameter in a major axis direction, a first tapered portion that is provided on a rear end side of the first straight portion and has an outer diameter that increases toward the rear end side of the core shaft, The large diameter portion has a second straight portion having a substantially constant outer diameter in the major axis direction, a second tapered portion that is provided on the distal side of the second straight portion and has an outer diameter that increases toward the rear end side of the core shaft.

5. 5. The guidewire of claim 4, a coil covering an outer periphery of the small diameter portion, a tip end of the coil is joined to a tip end of the small diameter portion by a tip side fixing portion, A guidewire, wherein a rear end of the coil is joined to the first tapered portion by a rear end fixed portion.

6. The guidewire according to any one of claims 1 to 5, The outer diameter of the main body portion of the core shaft is approximately constant in the longitudinal direction of the guidewire.

7. The guidewire according to any one of claims 3 to 5, The small diameter portion, the main body portion, and the large diameter portion of the core shaft are formed of a nickel-titanium alloy.

8. The guidewire according to any one of claims 3 to 5, A guidewire, wherein the portion of the core shaft that has the smallest outer diameter is the small diameter portion.

9. The guidewire according to any one of claims 1 to 8, A guidewire, wherein the portion of the core shaft that has the largest outer diameter is the large diameter portion.

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