Catheter for passing through a serpentine vascular system
The intravascular catheter with a decreasing stiffness profile and integrated core wire enables efficient navigation through tortuous vasculature by ensuring flexibility at the distal end, addressing the challenge of sharp bends in catheter insertion.
Patent Information
- Application Number
- JP2025501703
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-07-14
- Filing Date
- 2023-07-14
- Publication Date
- 2025-07-10
AI Technical Summary
Catheters face challenges in navigating tortuous vasculature due to the need to bend sharply, often at angles of 60-180 degrees, which can be difficult with existing designs.
An intravascular catheter with a stiffness profile that decreases from the proximal to the distal end, featuring segments with varying stiffness levels, utilizing a core wire integrated within the catheter to achieve optimal flexibility and maneuverability through complex vascular structures.
The catheter design allows for easier navigation through tortuous vasculature by ensuring flexibility at the distal end, reducing the risk of penetration and enhancing maneuverability in sharp curves, thus facilitating effective medical procedures.
Smart Images
Figure 2025522104000001_ABST
Abstract
Description
Cross - Reference to Related Applications
[0001] This application claims the benefit and priority of U.S. Provisional Application No. 63 / 368,463, filed on July 14, 2022, entitled "Catheter For Navigating Tortuous Vasculatures", the entire content of which is incorporated herein by reference. BACKGROUND OF THE INVENTION
[0002] In the treatment of various diseases, it is often necessary to operate a catheter within a tortuous vasculature to reach a distal anatomical structure. For example, in the treatment of stroke and other medical conditions, a catheter may need to reach the distal end of a patient's vasculature. To reach the distal vasculature, it is necessary to properly advance the catheter within the tortuous vasculature, and in the process, the catheter often has to be bent sharply, for example, at an angle of 60 - 180 degrees. SUMMARY OF THE INVENTION
[0003] Describes an intravascular catheter having an optimal stiffness profile suitable for passing through a tortuous vasculature.
[0004] In one embodiment of the present invention, the stiffness decreases between the distal end and the proximal end.
[0005] One embodiment of the present invention has a proximal segment with uniform stiffness, an intermediate segment with different and decreasing stiffness, and a distal segment with uniform stiffness.
[0006] In one embodiment of the present invention, the stiffness of the proximal segment is higher than that of the intermediate segment, and the stiffness of the intermediate segment is higher than that of the distal segment.
[0007] One embodiment of the present invention has an inner core wire. The core wire may be integrated along the axis of the catheter. The material and dimensional profile of the core wire can be adjusted to obtain a desired rigidity profile along the axis of the catheter. By using one or more core wires, the need for polymer jackets of different hardnesses or braided portions of variable pitch can be reduced.
[0008] The core wire may function as a guide wire built into the jacket of the catheter. In an exemplary embodiment, such a core wire is fixed to at least a part of the length of a coiled liner tube. In a particular embodiment, at least a part of the length of the inner core wire towards its distal end may be tapered.
[0009] The core wire may terminate at a position distal to the distal end of the catheter. As an example, the core wire may terminate at the intermediate segment of the elongate member of the catheter, and the distal segment of the elongate member can retain high flexibility by having no core wire. The distal segment may constitute about 10% - 12% of the catheter.
[0010] In another embodiment of the present invention, the core wire does not have to have a tapered end, thereby avoiding penetration or puncture of the outer jacket of the catheter. In such an embodiment, instead, the distal end of the core wire may be wound around the liner tube. In such an embodiment, the core wire may have a uniform outer diameter or at least a part of its length may be tapered.
[0011] In another embodiment of the present invention, a plurality of (for example, two or more) core wires may be arranged and fixed around the radial circumference of the liner tube. As an example, four core wires may be fixed at intervals of 90 degrees each along the circumference in the radial direction of the liner tube, and the four core wires each have a different length, thereby imparting a desired, decreasing stiffness profile between the proximal end and the distal end of the catheter.
Brief Description of the Drawings
[0012] These and other aspects, features, and advantages of the embodiments of the present invention will become apparent and clear from the following description of the embodiments of the present invention.
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[0030] Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention may be implemented in many different forms and should not be construed as limited to the embodiments described herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terms used in the detailed description of the embodiments shown in the accompanying drawings are not intended to limit the present invention. In the drawings, like numbers refer to like elements.
[0031] In this specification, the terms distal and proximal are used. Unless otherwise defined, distal and proximal are used with reference to the physician during the procedure. Thus, proximal tends to be closer to the physician and distal tends to be closer to the target site within the patient's body. However, these terms apply regardless of whether the device is inside or outside the patient's body.
[0032] In an exemplary embodiment of the intravascular catheter 100, the stiffness profile decreases between the proximal end 104 and the distal end 105 to facilitate passage through tortuous vasculature. The intravascular catheter 100 may include a tubular elongate member 102 having a proximal segment 102A, an intermediate segment 102B, and a distal segment 102C. A liner tube 107 may extend within the elongate member 102, and a passage 103 (i.e., lumen) may be defined within the elongate member 102.
[0033] The proximal segment 102A may have a first rigidity, the intermediate segment 102B may have a second rigidity, and the distal segment 102C may have a third rigidity. The first rigidity may be higher than the second rigidity, and the second rigidity may be higher than the third rigidity. The first rigidity and the third rigidity may be uniform across their respective segments 102A, 102C, and the second rigidity may decrease (or increase) in at least a portion of the intermediate segment 102B.
[0034] In an exemplary embodiment, a stiffness profile may be imparted to the elongate member 102 by using a core wire 110 that is fixed within the outer jacket 106 of the elongate member 102 and extends within the outer jacket 106. The outer diameter of the core wire 110 may be tapered in its longitudinal direction, whereby the stiffness between the proximal end 104 and the distal end 105 of the elongate member 102 may decrease. The core wire 110 may terminate at or proximal to the distal segment 102C of the elongate member 102, whereby the distal segment 102C may be more flexible than the proximal segment 102A and the intermediate segment 102B.
[0035] In an exemplary embodiment, the distal end 112 of the core wire 110 may be at least partially wound around the outer periphery of the liner tube 107, whereby the possibility of the distal end 112 of the core wire 110 penetrating the elongate member 102 (e.g., the outer jacket 106 of the elongate member 102) can be reduced or eliminated. The coil portion 114 of the core wire 110 may be disposed at or proximal to the distal segment 102C of the elongate member 102. In embodiments where the distal segment 102C of the elongate member 102 includes an enlarged portion 105A, the coil portion 114 of the core wire 110 may be disposed at or proximal to the proximal end of the enlarged portion 105A.
[0036] In another exemplary embodiment, a plurality of core wires 115A, 115B, 115C, 115D may be fixed and extend within the outer jacket 106 of the elongate member 102, respectively. The lengths of the core wires 115A, 115B, 115C, 115D may be set such that the lengths are shifted so as to be different for each of the core wires 115A, 115B, 115C, 115D. In this way, the rigidity of the elongate member 102 may be gradually decreased along its length. The core wires 115A, 115B, 115C, 115D may be arranged radially on the outer periphery of the liner tube 107. In some embodiments, each of the core wires 115A, 115B, 115C, 115D may be composed of a first material 116 and a second material 117 having a higher rigidity than the first material 116, the second material 117 being connected to the first material 116.
[0037] FIG. 1 shows an example of an intravascular catheter 100. The methods and systems described herein are applicable to a wide variety of catheters 100 and should not be construed as limited to only a particular type or configuration of catheter. The catheter 100 may be a microcatheter. For example, the catheters shown and described in U.S. Patent No. 10,682,493 entitled "Intravascular Treatment Site Access" and U.S. Patent No. 10,456,552 entitled "System and Methods for Intracranial Vessel Access" may be utilized. U.S. Patent Nos. 10,682,493 and 10,456,552 are hereby incorporated by reference in their entirety.
[0038] Exemplary embodiments of the intravascular catheter shown in FIG. 1 include a hub 101 and an elongate member 102 connected to the hub 101 and extending from the hub 101. The hub 101 may include a passage 101A that can be in fluid connection with the passage 103 of the catheter 100, and various instruments and devices can be inserted into the passage 103 through the passage 101A. The passage 101A of the hub 101 may be concentric with the passage 103 of the elongate member 102.
[0039] The elongate member 102 may include a proximal end 104 connected to the hub 101 and a distal end 105 opposite to the proximal end 104. The elongate member 102 may have an enlarged portion 105A at its distal end 105 or on its proximal side. The enlarged portion 105A may have a diameter larger than other portions of the elongate member 102. The enlarged portion 105A may be disposed only on the distal segment 102C and may not extend to the proximal segment 102A and the intermediate segment 102B.
[0040] The elongate member 102 may include an outer jacket 106 made of a flexible material such as various polymer materials. Examples of polymer materials that can be used to form the outer jacket 106 include, but are not limited to, thermoplastic materials such as PEBAX (Pebax), PET, polytetrafluoroethylene (PTFE), polyimide, and composite materials. The thickness and density of the outer jacket 106 vary depending on the embodiment to suit different applications and can be adjusted according to the application. However, since the outer jacket 106 contributes to the overall rigidity of the catheter 100, it should be considered when designing the optimal rigidity profile.
[0041] The outer jacket 106 of the elongate member 102 may have different outer diameters along the length of the elongate member 102. For example, in the exemplary embodiments shown in FIGS. 2, 3, 5 to 7, it can be seen that the outer jacket 106 of the elongate member 102 includes a first segment 106A having a first outer diameter, a second segment 106B having a second outer diameter, and a third segment 106C having a third outer diameter.
[0042] The first outer diameter may be larger than the second outer diameter, and the second outer diameter may be larger than the third outer diameter. In the illustrated embodiment, the first segment 106A of the outer jacket 106 may have a uniform first outer diameter, the second segment 106B of the outer jacket 106 may have a tapered (i.e., reduced diameter) second outer diameter, and the third segment 106C of the outer jacket 106 may have a uniform third outer diameter.
[0043] Continuing to refer to FIGS. 2, 3, 5-7, it can be seen that the elongate member 102 may be tapered only from a large diameter to a small diameter along a first radially extending edge. For example, the top of the elongate member 102 may be tapered, and the bottom of the elongate member 102 may not be tapered and may be straight and rounded.
[0044] A liner tube 107 may extend within the elongate member 102 so as to define a passageway 103, and the diameter of the liner tube 107 may be smaller than the diameter of the elongate member 102 in which the liner tube 107 extends. The passageway 103 may extend across the liner tube 107. Thus, the elongate member 102 may define an outer tube, and the liner tube 107 may define an inner tube that extends within the outer tube.
[0045] The position of the passageway 103 in the elongate member 102 varies depending on the embodiment. For example, in the exemplary embodiments shown in FIGS. 4 and 5, the liner tube 107 may extend into the lower half in the height direction of the outer jacket 106 of the elongate member 102. In other words, the passageway 103 may be disposed below the longitudinal axis extending through the center of the elongate member 102. In the exemplary embodiments shown in FIGS. 9 and 13, the passageway 103 may be disposed at the center of the elongate member 102.
[0046] The diameters of the elongated member 102 and the passage 103, and their ratios, may be varied depending on the embodiment in order to adapt to different applications. Therefore, the sizes of the elongated member 102 and the passage 103 respectively, and their ratios, should not be construed as being limited to the illustrated exemplary embodiments.
[0047] The liner tube 107 (i.e., the passage 103) may have the same length as the elongated member 102, but depending on the embodiment, the liner tube 107 may be longer or shorter than the elongated member 102. The liner tube 107 may be fixed within the elongated member 102, and it may or may not be removable. The liner tube 107 may be formed in a coiled shape as shown, and the coil wire 108 may be wound around at least a part of the liner tube 107. The pitch of the coil wire 108 may vary depending on the embodiment. The pitch of the coil wire 108 may be uniform throughout the length of the liner tube 107, or may vary depending on the longitudinal portion of the liner tube 107.
[0048] As shown in FIG. 1, the elongated member 102 of the catheter 100 may include a proximal segment 102A, an intermediate segment 102B, and a distal segment 102C. The proximal segment 102A may constitute a first length of the elongated member 102 between its proximal end 104 and the intermediate segment 102B. The intermediate segment 102B may be located between its proximal segment 102A and the distal segment 102C and may constitute a second length of the elongated member 102. The distal segment 102C may be between the intermediate segment 102B of the elongated member 102 and the distal end 105 and may constitute a third length of the elongated member 102.
[0049] In the exemplary embodiment shown in FIG. 1, the distal end 105 of the elongated member 102 may have an enlarged portion 105A that is larger in diameter than other portions of the elongated member 102 (e.g., the proximal segment 102A and the intermediate segment 102B), but the enlarged portion 105A may be omitted as shown in FIGS. 14A and 14B.
[0050] The lengths of the respective segments 102A, 102B, and 102C may vary depending on the embodiment. In the various illustrated embodiments, the length of the proximal segment 102A may be longer than that of the intermediate segment 102B. The length of the distal segment 102C may be longer than that of the intermediate segment 102B.
[0051] The ratio of the lengths of the various segments 102A, 102B, and 102C may vary depending on the embodiment. In one embodiment, the sum of the lengths of the proximal segment 102A, the intermediate segment 102B, and the distal segment 102C, that is, the length of the entire elongated member 102, may be 150 to 165 centimeters. However, the above dimensions are merely illustrative, and the elongated member 102 may be longer or shorter than the above dimensions depending on the use of the catheter 100.
[0052] In an exemplary embodiment, the length of the intermediate segment 102B measured between the proximal segment 102A and the distal segment 102C may be 6 to 16 centimeters. The length of the distal segment 102C measured from the distal end 105 to the proximal end 104 of the elongated member 102 may be 12 to 26 centimeters. Thus, in an exemplary embodiment, the length of the distal segment 102C may be about 7% to 16% of the length of the elongated member 102 of the catheter 100.
[0053] In an exemplary embodiment, the length of the elongated member 102 may be from 150 centimeters to 165 centimeters. Also, the length of the distal segment 102C measured in the direction from the distal end 105 to the proximal end 104 of the elongated member 102 and in which the core wire 110 does not extend as described later may be from 15 centimeters to 20 centimeters. In another exemplary embodiment, the combined length of the proximal segment 102A, the intermediate segment 102B, and the distal segment 102C may be 165 centimeters, and the length of the distal segment 102C may be 16.5 centimeters.
[0054] The specific length of the distal segment 102C is dimensioned to have a higher flexibility than the proximal segment 102A and the intermediate segment 102B, and it has been confirmed that the rigidity profile is optimal for passing through a tortuous vascular system. For example, by increasing the flexibility (and decreasing the rigidity) of the final 7% - 16% of the length of the elongate member 102, the distal segment 102C can be easily manipulated and is ensured to easily pass through a vascular system having sharp curves. By omitting the core wire 110 from the final 7% - 16% of the length of the elongate member 102, the distal end 105 of the elongate member 102 has increased flexibility for turning into and passing through the bent portions in a tortuous vascular system with sharp curves.
[0055] Each of the lengths described above is for illustrative purposes only and should not be construed as limiting the scope. The length (and the ratio of each length) may vary depending on the embodiment to suit each application and treatment.
[0056] The elongate member 102 of the catheter 100 may have a uniform diameter over its length, and in some embodiments shown in FIGS. 2, 3, and 6 - 7, it may be tapered over the length of one or more of the segments 102A, 102B, 102C. Therefore, the uniform diameter of the elongate member 102 as shown, for example, in FIGS. 1, 14A, and 14B should not be construed as limiting the scope.
[0057] In at least the exemplary embodiments shown in FIGS. 2, 3, and 5-7, it can be seen that the elongated member 102 of the catheter 100 is tapered along at least a portion of the length of the intermediate segment 102B. In such an embodiment, the outer jacket 106 of the elongated member 102 may sequentially include a first segment 106A, a second segment 106B, and a third segment 106C having different outer diameters, respectively. The first segment 106A has a uniform first outer diameter, the second segment 106B has a tapered second outer diameter that can be smaller than the first outer diameter, and the third segment 106C has a uniform third outer diameter that can be smaller than the first outer diameter and the second outer diameter.
[0058] Depending on the embodiment, the taper of the diameter of the elongated member 102 may continue to at least a portion of the length of the distal segment 102C. Depending on the embodiment, the intermediate segment 102B of the elongated member 102 may be tapered, and the proximal segment 102A and the distal segment 102B of the elongated member 102 may have a uniform diameter. In another exemplary embodiment, the proximal segment 102A of the elongated member 102 may have a uniform diameter, and both the intermediate segment 102B and the distal segment 102C may be tapered. In another exemplary embodiment, the distal segment 102C may have the enlarged portion 105A described herein, and the enlarged portion 105A may have a larger diameter than any other portion of the elongated member 102.
[0059] Generally, the intravascular catheter 100 has an optimal stiffness profile for passing through tortuous vascular systems such as the Type II aortic arch, the Type III aortic arch, etc. The intravascular catheter 100 may have a stiffness profile that varies between the proximal end 104 and the distal end 105. Each segment 102A, 102B, 102C may have a different stiffness. The stiffness of the distal segment 102C may be lower (i.e., more flexible) than that of the proximal segment 102A and the intermediate segment 102B. Thereby, the distal segment 102C can more easily wrap around, bend, or be manipulated around the sharp curves of the tortuous vascular system.
[0060] In an exemplary embodiment, the stiffness of the intravascular catheter 100 may decrease (e.g., stepwise) between the proximal end 104 and the distal end 105 of the elongate member 102. In such an exemplary embodiment, the rate of decrease of the stiffness of the intravascular catheter 100 may be uniform over its length. In another exemplary embodiment, the rate of decrease of the stiffness of the intravascular catheter 100 may vary, for example, it may have both a portion with uniform stiffness and a portion with decreasing stiffness.
[0061] In an exemplary embodiment, the intravascular catheter 100 may have a first stiffness along the length of the proximal segment 102A. The first stiffness of the elongate member 102 along the length of the proximal segment 102A may be uniform. That is, it may be constant over the length of the proximal segment 102A. However, in other embodiments, the first stiffness may increase or decrease along the proximal segment 102A of the intravascular catheter 100. The proximal segment 102A may constitute the proximal length of the elongate member 102 from its proximal end 104 to the intermediate segment 102B.
[0062] In an exemplary embodiment, the intravascular catheter 100 may have a second stiffness along the length of the intermediate segment 102B. The second stiffness may be lower than the first stiffness. Thus, the stiffness of the intermediate segment 102B may be lower than the stiffness of the proximal segment 102A, and the stiffness of the elongate member 102 may decrease between the proximal segment 102A and the intermediate segment 102B. The second stiffness may be uniform over the intermediate segment 102B, or may decrease (or increase) at various rates along the length of the intermediate segment 102B. The intermediate segment 102B may constitute an intermediate length of the elongate member 102 between its proximal end 104 and its distal end 105. The intermediate segment 102B may constitute the length of the elongate member 102 from its proximal segment 102A to its distal segment 102C. That is, the intermediate segment 102B extends between the proximal segment 102A and the distal segment 102C of the elongate member 102.
[0063] In an exemplary embodiment, the intravascular catheter 100 may have a third stiffness along the length of the distal segment 102C. The third stiffness may be lower than the second stiffness. Thus, the stiffness of the distal segment 102C may be lower than the respective stiffnesses of the proximal segment 102B and the intermediate segment 102C. The third stiffness of the intravascular catheter 100 may be uniform over the distal segment 102C (i.e., may be constant over the length of the distal segment 102C), or may decrease (or increase) at various rates along the length of the distal segment 102C. The distal segment 102C may constitute the distal length of the elongate member 102 from the intermediate segment 102B to the distal end 105.
[0064] The method for achieving the desired stiffness profile of the intravascular catheter 100 may vary depending on the embodiment. In a first exemplary embodiment, the core wire 110 may be fixedly connected to the intravascular catheter 100, thereby imparting the desired stiffness profile to the catheter 100. Thus, the core wire 110 may extend in the intravascular catheter 100 in a non-removable state. For example, the core wire 110 may be integrated with the outer jacket 106 of the elongate member 102. The core wire 110 may extend across a lumen of the elongate member 102 that is separate and different from the passageway 103 of the elongate member 102. The lumen of the elongate member 102 in which the core wire 110 extends may be parallel to the passageway 103 of the elongate member 102. In some embodiments, the core wire 110 may be connected to the liner tube 107 at one or more positions along the length of the core wire 110, or consistently throughout the length.
[0065] The stiffness of the intravascular catheter 100 may be the sum of the stiffnesses of the outer jacket 106, the liner tube 107, and the core wire 110. Thus, in different embodiments, the core wire 110 may be configured to achieve the stiffness desired for passing through tortuous vasculature. In some embodiments, the core wire 110 may terminate at the distal end of the intermediate segment 102B (i.e., the core wire 110 may terminate at the origin of the distal segment 102C). In such an embodiment, the stiffness of the distal segment 102C may be the sum of the stiffnesses of the outer jacket 106 and the coiled liner tube 107 since the core wire 110 is not present in that segment 102C.
[0066] In the illustrated exemplary embodiments, the desired stiffness profile of the intravascular catheter 100 may be achieved by the use of a core wire 110 that extends at least partially within the intravascular catheter 100. In an exemplary embodiment, the core wire 110 may be tapered along at least one of the segments 102A, 102B, 102C of the elongate member 102. In another exemplary embodiment, the core wire 110 may transition into a coil portion 114 such that the distal end 112 of the core wire 110 is wound around the passageway 103. In another embodiment, a plurality of core wires 115A, 115B, 115C, 115D of different lengths and / or materials 116, 117 may extend within the intravascular catheter 100, and the plurality of core wires 115A, 115B, 115C, 115D may be disposed outside of the liner tube 107.
[0067] In embodiments where the core wire 110 is at least partially tapered along its length, the length and angle of the taper may vary depending on the embodiment. In an exemplary embodiment, the core wire 110 may have a uniform outer diameter along the proximal segment 102A and may be tapered along the intermediate segment 102B. In one exemplary embodiment, the outer diameter of the distal end 112 (e.g., after the taper) of the core wire 110 in the intermediate segment 102B may be 12% - 14% of the outer diameter at the starting point of the core wire 110 in the proximal segment 102A.
[0068] For example, the outer diameter of the core wire 110 along the proximal segment 102A may be 0.05 - 0.07 centimeters. The outer diameter of the core wire 110 may gradually decrease to an outer diameter of 0.007 - 0.008 centimeters along the intermediate segment 102B. The length of the tapered outer diameter of the core wire 110 may be 7 - 16 centimeters. Such a configuration has been confirmed to be optimal for passing through the sharp curves of a tortuous vascular system.
[0069] Each of the above dimensions is for illustrative purposes only and should not be construed as limiting the scope. The length and angle may vary depending on the embodiment to suit each use of the core wire 110.
[0070] The materials 116 and 117 of the core wire 110 may vary depending on the embodiment. In an exemplary embodiment, the core wire 110 may be made of stainless steel. In another exemplary embodiment, the core wire 110 may be a nickel-titanium alloy (i.e., nitinol). In another exemplary embodiment, the core wire 110 may include both stainless steel and nitinol.
[0071] Depending on the embodiment, the core wire 110 may include both stainless steel and nitinol. For example, the core wire 110 along the proximal segment 102A may be composed of stainless steel, and the core wire 110 along the intermediate segment 102B may be composed of nitinol. With such a configuration, the rigidity increases toward the proximal end 104 and the flexibility increases toward the distal end 105.
[0072] The core wire 110 is generally integrated with or disposed within the outer jacket 106 of the elongated member 102. Thus, the core wire 110 may be fixed within the elongated member 102 so that the core wire 110 cannot be removed. The core wire 110 may be fixed or disposed with respect to the liner tube 107 (e.g., with respect to the outer periphery of the passage 103) as shown, but depending on the embodiment, the core wire 110 may instead extend parallel to the liner tube 107 without contacting the liner tube 107.
[0073] In an embodiment where the core wire 110 is fixed to the liner tube 107, the method of fixing the core wire 110 to the liner tube 107 may be different. Although an adhesive (e.g., glue) can be used to fix the core wire 110 to the liner tube 107, generally an adhesive affects the rigidity profile of the elongate member 102, and thus such an embodiment must be considered. In an exemplary embodiment, a heat shrink tube may be used to fix the core wire 110 to the liner tube 107 and to fix the liner tube 107 within the outer jacket 106. In such a preferred embodiment, when applying the heat shrink tube, a mandrel or the like may be inserted into the liner tube 107 to maintain the passageway 103.
[0074] Figures 2-5 illustrate exemplary embodiments of an intravascular catheter 100 in which the rigidity profile decreases between the proximal end 104 and the distal end 105. In the illustrated embodiment, an elongate core wire 110 may extend within the intravascular catheter 100. The core wire 110 may be fixed to or in contact with the passageway 103 (e.g., the outer periphery of the liner tube 107). In an exemplary embodiment, the core wire 110 may be fixed to the upper end of the outer periphery of the liner tube 107. However, in another embodiment, the core wire 110 may be fixed at various other radial positions (e.g., the bottom or side) of the outer periphery of the liner tube 107. In another embodiment, the core wire 110 may not be fixed to or in contact with the liner tube 107 and instead may extend parallel to the liner tube 107 within the outer jacket 106.
[0075] The core wire 110 may have the same length as the elongate member 102, or may be longer or shorter than the elongate member 102. In an exemplary embodiment, the proximal end of the core wire 110 may extend outwardly from the proximal end 104 of the elongate member 102 and extend into the path 101A of the hub 101. In an exemplary embodiment, about 1 centimeter of the length of the core wire 110 may extend beyond the proximal end 104 of the elongate member 102 and into the path 101A of the hub 101 of the catheter 100. With such a configuration, the operation of the hub 101 by the physician is reliably transmitted to the core wire 110.
[0076] In the illustrated exemplary embodiment, the core wire 110 is shown as having a uniform outer diameter over its length along the proximal segment 102A of the elongate member 102. The outer diameter of the core wire 110 along the proximal segment 102A of the elongate member 102 may be composed of different sizes. In an exemplary embodiment, the outer diameter may be from 0.05 to 0.07 centimeters.
[0077] The core wire 110 may thus have a first rigidity along the proximal segment 102A of the elongate member 102. The core wire 110 may maintain the same outer diameter, i.e., the same rigidity, from the proximal end 104 to the intermediate segment 102B over the entire length of the proximal segment 102A of the elongate member 102.
[0078] As best seen in FIGS. 2 and 3, the core wire 110 may have a tapered portion 113 (i.e., a taper) where the outer diameter decreases over the length of the intermediate segment 102B of the elongate member 102. The rate at which the outer diameter of the tapered portion 113 of the core wire 110 decreases (e.g., the decrease in outer diameter per unit length) along the intermediate segment 102B may vary depending on the embodiment and should not be construed as limited to the illustrated exemplary embodiment. The tapered portion 113 extends over the entire length of the intermediate segment 102B as shown in FIGS. 2 - 3 and may extend shorter or longer than the intermediate segment 102B in another embodiment.
[0079] In the embodiments shown in FIGS. 2 and 3, the core wire 110 may terminate at its distal end 112 where it changes from the intermediate segment 102B to the distal segment 102C of the elongate member 102. Thus, the distal end 112 of the core wire 110 may terminate proximal to the starting point of the enlarged portion 105A of the elongate member 102, and the enlarged portion 105A may be able to pass through a sharp curve in a tortuous vascular system.
[0080] The distal end 112 of the core wire 110 may have an outer diameter that is smaller than the outer diameter of the core wire 110 along the proximal segment 102A of the elongate member 102. For example, the outer diameter of the distal end 112 of the core wire 110 may be 12% - 14% of the outer diameter of the core wire 110 along the proximal segment 102A of the elongate member 102. In an exemplary embodiment, the outer diameter of the distal end 112 of the core wire 110 may be between 0.007 and 0.008 centimeters. With such a configuration, the rigidity of the core wire 110 decreases stepwise along the length of the elongate member 102, and an optimal rigidity profile for passing through a tortuous vascular system with sharp curves can be reliably obtained.
[0081] Continuing to refer to FIGS. 2 and 3, it can be seen that the core wire 110 may not extend within the distal segment 102C of the elongate member 102. With such a configuration, the flexibility of the distal segment 102C of the elongate member 102 and the distal end 105 can be ensured, and operations necessary for passing through a tortuous vascular system such as the aortic arch become possible. Thus, in such an embodiment, the core wire 110 need not contribute to the rigidity of the distal segment 102C of the elongate member 102, and the overall rigidity of the distal segment 102C may be the combined rigidity of the outer jacket 106 and the liner tube 107 (including any coil wires 108 wound around the liner tube 107).
[0082] Figures 4 and 5 are cross-sectional views of the elongated member 102, showing the liner tube 107 and the core wire 110. Figure 4 is a cross-sectional view taken along line 4-4 of Figure 3, showing within the proximal segment 102A of the elongated member 102. As shown in Figure 4, the outer diameter of the core wire 110 is approximately the same as the outer diameter of the liner tube 107. However, in another exemplary embodiment, the outer diameter of the core wire 110 may be smaller or larger compared to the outer diameter of the liner tube 107, thereby achieving different desired stiffness profiles.
[0083] Referring to Figure 4, it can be seen that the passage 103 (i.e., the liner tube 107) may be disposed below the longitudinal axis extending through the center of the elongated member 102 along at least a portion of the length of the elongated member 102. Similarly, it can be seen that the core wire 110 may be disposed above the longitudinal axis extending through the center of the elongated member 102. Such a configuration may improve passage through a tortuous vascular system with sharp curves.
[0084] Figure 5 is a cross-sectional view taken along line 5-5 of Figure 3, showing the distal end 112 of the tapered core wire 110 at the end of the intermediate segment 102B of the elongated member 102. As shown in Figure 5, the outer diameter of the distal end 112 of the core wire 110 may be smaller than the outer diameter of the liner tube 107. In one exemplary embodiment, the outer diameter of the distal end 112 of the core wire 110 may be about 12% - 14% of the outer diameter of the liner tube 107. In Figure 5, it can be confirmed that the outer jacket 106 of the elongated member 102 may also be tapered inwardly along the length of its second segment 106B and may coincide with the taper of the core wire 110 along the intermediate segment 102B.
[0085] Figures 6-9 show exemplary embodiments of an intravascular catheter 100 in which the stiffness profile decreases between a proximal end 104 and a distal end 105. As in the previously described embodiments, an elongate core wire 110 may extend within the intravascular catheter 100. The core wire 110 may be fixed to the outer periphery of the passage 103, for example, by being fixed to the outer periphery of the liner tube 107. The figures show the core wire 110 fixed to or in contact with the upper end of the outer periphery of the liner tube 107, but in another embodiment, the core wire 110 may be fixed or in contact with various positions on the outer periphery of the liner tube 107. In another embodiment, the core wire 110 may not be in contact with or fixed to the liner tube 107, and instead may extend parallel to the liner tube 107 within the outer jacket 106.
[0086] Similar to the previously described embodiments, the core wire 110 may have a uniform outer diameter along the length of the proximal segment 102A of the elongate member 102. Different outer diameters may be utilized to obtain different desired stiffness profiles suitable for different applications in different embodiments. In an exemplary embodiment, the outer diameter of the core wire 110 along the proximal segment 102A may be from 0.05 to 0.07 centimeters.
[0087] The core wire in the embodiments shown in Figures 6-9 may have a uniform first stiffness along the proximal segment 102A of the elongate member 102. Thus, as shown in Figures 6-9, the core wire 110 may maintain the same outer diameter and the same stiffness from the proximal end 104 to the intermediate segment 102B throughout the length of the proximal segment 102A of the elongate member 102.
[0088] As best seen from FIGS. 6 and 7, the core wire 110 along the length of the intermediate segment 102B of the elongate member 102 may have an outer diameter that at least partially decreases (i.e., is tapered). The rate of reduction of the outer diameter of the core wire 110 along the intermediate segment 102B may vary depending on the embodiment and should not be construed as limited to the illustrated exemplary embodiment.
[0089] In an exemplary embodiment as shown in FIGS. 6 and 7, the core wire 110 may have a first segment 113A having a first uniform outer diameter. From the proximal end 104 of the elongate member 102, the first segment 113A of the core wire 110 having the first uniform outer diameter may extend over the length of its proximal segment 102A and may terminate at the intermediate segment 102B of the elongate member 102.
[0090] The core wire 110 may have a second segment 113B having a second tapered outer diameter by which the outer diameter of the core wire 110 may decrease. The second segment 113B may extend over a portion of the intermediate segment 102B. The degree of taper (i.e., the amount and rate of decrease of the outer diameter) may vary depending on the embodiment.
[0091] The core wire 110 may have a third segment 113C having a third uniform outer diameter. The third segment 113C may extend over a portion of the intermediate segment 102B. The third segment 113C may terminate at a coil portion 114 where the distal end 112 of the core wire 110 is wound around the liner tube 107 as shown. The coil portion 114 has a helical shape and may be wound around the outer periphery of the liner tube 107 a different number of times depending on the embodiment.
[0092] The first segment 113A, the second segment 113B, and the third segment 113C of the core wire 110 may be integrated. The third uniform outer diameter of the third segment 113C may be smaller than the first uniform outer diameter of the first segment 113A. The second tapered outer diameter of the second segment 113B may be tapered from the first uniform outer diameter to the third uniform outer diameter.
[0093] Accordingly, it can be seen that the core wire 110 may extend across the entire intermediate segment 102 of the elongate member 102, and the core wire 110 may have a tapered second segment 113B having a tapered outer diameter and a third segment 113C having a uniform outer diameter that is smaller than the outer diameter of the first segment 113A of the core wire 110 in the proximal segment 102A of the elongate member 102.
[0094] The respective lengths of the tapered second segment 113B and the uniform third segment 113C of the core wire 110 extending along the intermediate segment 102B of the elongate member 102 may vary depending on the embodiment. In some embodiments, the core wire 110 may be tapered across the entire length of the intermediate segment 102B of the elongate member 102 proximal to the termination at the coil portion 114, as described below. In such an embodiment, the uniform third segment 113C may be omitted. In another embodiment, the core wire 110 may maintain a uniform outer diameter across the entire length of the intermediate segment 102B of the elongate member 102 proximal to the termination at the coil portion 114.
[0095] As shown in FIGS. 6-8, the core wire 110 may terminate at a coil portion 114 where the distal end 112 of the core wire 110 is wound around the liner tube 107. Such an embodiment may be desirable in eliminating the risk that the distal end 112 of the core wire 110 penetrates the outer jacket 106 of the elongate member 102 and injures the patient, for example, when bending sharply. By winding the core wire 110 around the liner tube 107, the risk that the distal end 112 of the core wire 110 pierces or penetrates the elongate member 102 is substantially reduced.
[0096] Referring to FIGS. 6 and 7, it can be seen that the core wire 110 may not extend or pass through any portion of the distal segment 102C of the elongate member 102. Thus, the distal segment 102C of the elongate member 102 may have a high flexibility (i.e., lower rigidity) compared to both the proximal segment 102A and the intermediate segment 102B. Such a configuration facilitates the sharp bends that often occur when passing through a tortuous vascular system commonly found, for example, in the aortic arch.
[0097] In the illustrated exemplary embodiment, it can be seen that the coil portion 114 of the core wire 110 may include three windings around the liner tube 107. However, it should be understood that depending on the embodiment, the coil portion 114 may include more or fewer windings. Further, the pitch of the coil portion 114 may vary depending on the embodiment and should not be construed as limited to the illustrated exemplary embodiment. Further, in the figure, the coil portion 114 is shown as sharing the same outer diameter as the uniform third segment 113C of the coil wire 110, but depending on the embodiment, the coil portion 114 may be tapered when wound around the liner tube 107.
[0098] FIG. 8 shows a cross-sectional view of a part of the elongated member 102 bisected in the longitudinal direction. In the illustrated exemplary embodiment, it can be seen that the core wire 110 may be fixed to or in contact with the top of the liner tube 107 before the coil portion 114 is wound around the liner tube 107 and terminated. In another embodiment, the core wire 110 may instead extend along another radial position on the outer periphery of the liner tube 107.
[0099] FIG. 9 is a cross-sectional view taken along line 9-9 of FIG. 7. As shown in FIG. 9, the coil portion 114 may wind completely around the liner tube 107 to terminate the coil wire 110, and by doing so, prevent the coil wire 110 from converging at a single point and leave no exposed linear distal end 112 that can pierce or penetrate the outer jacket 106 of the elongated member 102. However, depending on the embodiment, the coil portion 114 may only be partially wound around the liner tube 107. For example, the coil portion 114 may be less than one full rotation. For example, depending on the embodiment, the coil portion 114 may be wound only half the outer circumference of the liner tube 107, and thus may be half a rotation.
[0100] FIGS. 10-13 show a third exemplary embodiment of the intravascular catheter 100 having a plurality of core wires 115A, 115B, 115C, 115D instead of a single core wire 110. In such an embodiment, core wires 115A, 115B, 115C, 115D having a uniform outer diameter along their respective lengths may be used instead of a taper. However, depending on the embodiment, one or more of the core wires 115A, 115B, 115C, 115D may have a taper along at least a part of their length.
[0101] In the illustrated embodiment, each of the four core wires 115A, 115B, 115C, and 115D extends within the intravascular catheter 100. It will be understood that depending on the embodiment, more or fewer core wires than the core wires 115A, 115B, 115C, and 115D may be used to achieve the desired stiffness profile. For example, in an exemplary embodiment, only two core wires 115A and 115B may be used. In another embodiment, three, five, or more core wires 115A, 115B, 115C, and 115D may be used.
[0102] Each of the core wires 115A, 115B, 115C, and 115D is shown as being fixed to or in contact with the outer periphery of the liner tube 107. In an exemplary embodiment best shown in FIGS. 10 and 13, the first core wire 115A may be fixed to or in contact with the top of the liner tube 107, the second core wire 115B may be fixed to or in contact with the first side of the liner tube 107, the third core wire 115C may be fixed to or in contact with the bottom of the liner tube 107, and the fourth core wire 115D may be fixed to or in contact with the second side of the liner tube 107. In another embodiment, one or more of the core wires 115A, 115B, 115C, and 115D may not be fixed to or in contact with the liner tube 107 and instead may extend parallel to the liner tube 107 within the outer jacket 106.
[0103] In the illustrated embodiment, each of the core wires 115A, 115B, 115C, and 115D may be arranged at equal intervals from each other in the radial direction of the outer periphery of the liner tube 107. Specifically, it can be seen that the core wires 115A, 115B, 115C, and 115D may be 90 degrees apart from adjacent core wires 115A, 115B, 115C, and 115D. However, in a particular embodiment, the intervals between the core wires 115A, 115B, 115C, and 115D on the outer periphery of the liner tube 107 may be different. For example, two or more of the core wires 115A, 115B, 115C, and 115D may be brought closer together.
[0104] As best shown in FIGS. 10-12, each of the core wires 115A, 115B, 115C, 115D may have a different length. Depending on the different lengths of the core wires 115A, 115B, 115C, 115D, the rigidity of the catheter 100 may be gradually decreased or functioned to decrease stepwise in the intermediate segment 102B of the elongate member 102. Thus, by terminating each of the core wires 115A, 115B, 115C, 115D at different positions in the intermediate segment 102B, the effective rigidity can be gradually decreased before the core wires 115A, 115B, 115C, 115D that finally terminate at the start position of the distal segment 102C terminate.
[0105] In the exemplary embodiment shown in FIG. 10, the third core wire 115C may be longer than the first core wire 115A, the second core wire 115B, and the fourth core wire 115D, the fourth core wire 115D may be longer than the first core wire 115A and the second core wire 115B, and the first core wire 115A may be longer than the second core wire 115B. However, such a configuration is shown as an exemplary embodiment only, and various other alternative arrangements can be adopted depending on the embodiment.
[0106] In the figure, each of the core wires 115A, 115B, 115C, and 115D is shown as having a different length from each other. However, in certain embodiments, two or more of the core wires 115A, 115B, 115C, and 115D may have the same length. Also, the arrangement of the longest and shortest core wires 115A, 115B, 115C, and 115D shown in the figure is for illustrative purposes only and should not be construed as limiting the scope. For example, in the figure, the third core wire 115C that extends and is fixed along the bottom of the liner tube 107 is shown as the longest among the core wires 115A, 115B, 115C, and 115D, and the first core wire 115A that extends and is fixed along the top of the liner tube 107 is shown as the shortest among the core wires 115A, 115B, 115C, and 115D. However, alternatively, depending on the embodiment, the reverse configuration or various other configurations can be used.
[0107] To make the rigidity profile of the catheter 100 easier to control, one or more of the core wires 115A, 115B, 115C, and 115D may be made of different materials. The figure shows that the core wires 115A, 115B, 115C, and 115D are composed of two materials 116 and 117. The first material 116 that constitutes the proximal side of each core wire 115A, 115B, 115C, and 115D may be a material that is more rigid or harder, such as stainless steel. The second material 117 that is coupled to the distal end of the first material 116 to form the integral core wires 115A, 115B, 115C, and 115D and may constitute the distal portion of each core wire 115A, 115B, 115C, and 115D may be a material with low rigidity (i.e., more flexible), such as nitinol.
[0108] The lengths of the materials 116 and 117 used for the respective core wires 115A, 115B, 115C, and 115D may vary depending on the embodiment. In the figure, the portion formed by the second material 117 of each core wire 115A, 115B, 115C, and 115D is shown to be shorter than the portion formed by the first material 116, but the reverse configuration may be used in a specific embodiment. In another exemplary embodiment, the lengths of the first material 116 and the second material 117 may be the same. Depending on the embodiment, the entirety of each core wire 115A, 115B, 115C, and 115D may be composed of a single material 116 or 117. In another embodiment, two or more types of materials may be fused to form the core wires 115A, 115B, 115C, and 115D.
[0109] FIG. 12 is a cross-sectional view of bisecting a part of the elongated member 102 in the longitudinal direction. In the illustrated embodiment, the first core wire 115A is shown as extending and being fixed along the top of the liner tube 107, and the third core wire 115C is shown as extending and being fixed along the bottom of the liner tube 107. The sizes of the core wires 115A, 115B, 115C, 115D and the liner tube 107 may be different from those illustrated depending on the embodiment.
[0110] FIG. 13 is a cross-sectional view taken along line 13-13 of FIG. 11. As shown in FIG. 13, each of the four core wires 115A, 115B, 115C, and 115D may be arranged radially on the outer periphery of the liner tube 107. The core wires 115A, 115B, 115C, and 115D may be directly fixed to or in contact with the liner tube 107, or may be held in a fixed state without contact, parallel to the liner tube 107 within the outer jacket 106. This figure is for illustrative purposes only, and the ratio of the diameters of the core wires 115A, 115B, 115C, 115D and the liner tube 107 may vary depending on the embodiment.
[0111] Figures 14A and 14B illustrate an intravascular catheter 100 that travels through or across the aortic arch. Figure 14A shows a Type II aortic arch and Figure 14B shows a Type III aortic arch. The exemplary intravascular catheter 100 shown in Figures 14A and 14B is simplified for illustrative purposes, but it will be understood that such an intravascular catheter 100 has, as described above, an enlarged portion 105A, or segments 106A, 106B, 106C, with different outer diameters in its outer jacket 106.
[0112] In use, the intravascular catheter 100 may be inserted via the descending aorta and advanced through the aortic arch. The intravascular catheter 100 may turn sharply to the right and enter the brachiocephalic artery. The catheter 100 may have a more flexible distal segment 102C, and the distal segment 102C of the catheter 100, i.e., the distal end 105, may be configured to easily pass such sharp curves. As in the illustrated embodiment, the intravascular catheter 100 may subsequently enter the right common carotid artery.
[0113] In an optimal stiffness profile of the intravascular catheter 100, the stiffness of the catheter 100 decreases between the proximal end 104 and the distal end 105 along its length and may include a flexible distal segment 102C. This optimal stiffness profile allows a physician to more easily and efficiently manipulate the catheter 100 within the aortic arch while reducing or eliminating the risk of the catheter 100 being pushed back into the ascending aorta. Although the figures show the catheter 100 traveling through the aortic arch to the right common carotid artery, it should be understood that various other routes are available with the systems and methods described herein. For example, the catheter 100 may instead travel via the right subclavian artery, the left common carotid artery, or the left subclavian artery, each of these routes enabled by an individual optimal stiffness profile of the catheter 100.
[0114] Figures 15A and 15B show graphs comparing the stiffness of different distance ranges from the distal end 105 in an exemplary embodiment of the catheter 100. Both figures compare the load values (gram force, GF) against the distance (centimeters, cm) from the distal end 105 of an exemplary embodiment of the catheter 100. Figure 15A shows the load values (GF) for the range of 0 cm to 40 cm from the distal end 105 of an exemplary embodiment of the catheter 100. Figure 15B shows the load values (GF) for the range of 12 cm to 26 cm from the distal end 105 of an exemplary embodiment of the catheter 100.
[0115] As shown in Figure 15A, in an exemplary embodiment of the catheter 100, in the range from 0 cm to 10 cm from the distal end 105, the load value may be negligible (e.g., less than 50 GF). The load value tends to increase between approximately 12 cm from the distal end 105 and approximately 25 cm from the distal end 105, and then tends to become flat between approximately 25 cm from the distal end 105 and approximately 40 cm from the distal end 105. The rate and degree of increase in load between 25 cm and 40 cm of distance vary depending on the illustrated embodiment, and each illustrated embodiment has a different ratio, degree, and length of taper in the distal segment 102C of the catheter 100.
[0116] Figure 15B focuses on the range of 25 cm to 40 cm from the distal end 105 of various exemplary embodiments shown in Figure 15A. As shown in Figure 15B, depending on the characteristics including the ratio, degree, and length of the taper along the length of the distal segment 102C of the catheter 100, the load generally increases in the range of less than 100 GF to 1000 GF and above 1800 GF.
[0117] As described above, in an exemplary embodiment of the catheter 100, the proximal segment 102A may have a first rigidity, the intermediate segment 102B may have a second rigidity that is less than or equal to the first rigidity, the distal segment 102C may have a third rigidity that is less than or equal to the first rigidity, and the second rigidity may decrease from the first rigidity to the second rigidity along the length of the intermediate segment 102B.
[0118] As shown in FIGS. 15A and 15B, the first rigidity may be greater than 1000 GF (for example, 1000 GF to 1850 GF), and the third rigidity may be less than 100 GF (for example, 0 GF to 100 GF, such as 50 GF depending on the embodiment). The length of the distal segment 102C measured from the distal end 105 to the proximal end 104 of the catheter 100 may be less than 20 cm. The length of the intermediate segment 102B measured from the proximal end of the distal segment 102C of the catheter 100 to the distal end of the proximal segment 102A of the catheter 100 may be less than 25 cm. However, it should be recognized that such values are for illustrative and explanatory purposes only and should not be construed as limiting the scope thereof.
[0119] Although the present invention has been described with respect to specific embodiments and applications, those skilled in the art can generate additional embodiments and modifications in light of this teaching without departing from the spirit of the invention claimed or exceeding its scope. Therefore, it should be understood that the drawings and description herein are provided as examples to facilitate understanding of the present invention and should not be construed as limiting its scope.
Claims
1. An elongate member having a proximal segment, an intermediate segment, and a distal segment, wherein the distal segment of the elongate member comprises an enlarged portion having a diameter larger than that of the proximal segment and the intermediate segment. An elongate member, A passage extending within the elongate member, A first core wire within the elongate member adjacent to the passage, wherein a distal end of the first core wire terminates in front of the enlarged portion of the elongate member. An intravascular catheter, characterized in that.
2. The length of the distal segment of the elongate member is 7% to 16% of the length of the elongate member, and the first core wire does not extend within the distal segment. The intravascular catheter according to claim 1, characterized in that.
3. The length of the elongate member is 150 centimeters to 165 centimeters, and the length of the distal segment is measured from the distal end of the elongate member toward the proximal end of the elongate member and is 15 centimeters to 20 centimeters. The intravascular catheter according to claim 2, characterized in that.
4. The first core wire is fixed to the outer periphery of the passage. The intravascular catheter according to claim 1, characterized in that.
5. The passage is disposed below the longitudinal axis extending through the center of the elongate member. The intravascular catheter according to claim 1, characterized in that.
6. The first core wire is disposed above the longitudinal axis extending through the center of the elongate member. The intravascular catheter according to claim 5, characterized in that.
7. The proximal end of the first core wire extends from the proximal end of the elongate member. The intravascular catheter according to claim 1, characterized in that.
8. The distal end of the first core wire is at least partially wound around the passage. The intravascular catheter according to claim 1, characterized in that.
9. The first core wire has a linear segment and a coiled segment, and the linear segment extends parallel to the passage and the coiled segment wound around the passage. The intravascular catheter according to claim 1, characterized in that.
10. The coiled segment of the first core wire is disposed within the intermediate segment of the elongate member. The intravascular catheter according to claim 9, characterized in that.
11. The intravascular catheter according to claim 1, wherein at least a part of the elongated member is tapered from a large diameter to a small diameter.
12. The intravascular catheter according to claim 1, further comprising a second core wire adjacent to the passage within the elongated member, wherein the length of the first core wire is different from that of the second core wire.
13. The intravascular catheter according to claim 12, wherein the distal end of the second core wire terminates in front of the enlarged portion of the elongated member.
14. The intravascular catheter according to claim 12, further comprising a third core wire adjacent to the passage within the elongated member and a fourth core wire adjacent to the passage within the elongated member.
15. The intravascular catheter according to claim 14, wherein the first core wire, the second core wire, the third core wire, and the fourth core wire are each arranged in the radial direction of the passage.
16. The intravascular catheter according to claim 14, wherein the first core wire, the second core wire, the third core wire, and the fourth core wire each have a different length.
17. The intravascular catheter according to claim 14, wherein the first core wire, the second core wire, the third core wire, and the fourth core wire each have a first segment made of stainless steel and a second segment made of nitinol.
18. The proximal segment has a first rigidity, the intermediate segment has a second rigidity less than the first rigidity, and the distal segment has a third rigidity less than the first rigidity. The intravascular catheter according to claim 1, wherein the second rigidity decreases from the first rigidity to the third rigidity along the length of the intermediate segment.
19. The intravascular catheter according to claim 18, wherein the first rigidity is at least 1,000 gram-forces (GF) and the third rigidity is less than 50 gram-forces (GF).
20. The intravascular catheter according to claim 19, wherein the length of the distal segment is measured from the distal end of the elongated member toward the proximal end of the elongated member and is less than 20 centimeters.
21. The length of the intermediate segment is measured from the proximal end of the distal segment toward the distal end of the proximal segment and is less than 25 centimeters, The intravascular catheter according to claim 20, characterized in that.
22. An elongate member having a proximal segment, an intermediate segment, and a distal segment, wherein the distal segment of the elongate member comprises an enlarged portion having a diameter larger than that of the proximal segment and the intermediate segment, An elongate member, A passage extending within the elongate member; A stiffening member adjacent to the passage within the elongate member, wherein the distal end of the stiffening member terminates in front of the enlarged portion of the elongate member, An intravascular catheter characterized by that.
23. The stiffening member consists of a core wire, The core wire includes a linear segment extending parallel to the passage and a coiled segment wound around the passage, The intravascular catheter according to claim 22, characterized in that.
24. The stiffening member consists of a plurality of core wires, The plurality of core wires each have a different length, The intravascular catheter according to claim 22, characterized in that.