Catheter for traversing tortuous blood vessels

Abstract

A catheter for traversing a tortuous blood vessel to reach a distant anatomical structure. The catheter may have an optimal stiffness profile such that a physician can safely and efficiently advance a large aperture catheter through such tortuous blood vessels. The catheter may have a greater stiffness at the proximal end than at the distal end such that the stiffness of the intravascular catheter tapers between the proximal end and the distal end. The core wire may extend through the proximal section and the intermediate section of the catheter to impart a desired stiffness. The core wire may be tapered at certain sections and may terminate before the distal end of the catheter such that the catheter has greater flexibility at or near its distal end. The distal end of the core wire may be crimped around a liner tube of an endovascular catheter. A plurality of core wires each having a different length may be used.

Description

Related Applications

[0001] This application claims the benefit of and priority to U.S. Provisional Application No. 63 / 368,463, filed on July 14, 2022, entitled “Catheter For Navigating Tortuous Vasculatures”; which is hereby incorporated by reference in its entirety. Background Art

[0002] Treatment of various conditions often requires the catheter to traverse through tortuous blood vessels to reach distant anatomical structures. For example, treatment of a stroke or other condition may require the catheter to reach a distant location in a patient's blood vessel. Reaching such a distant vessel may often require the catheter to traverse through tortuous blood vessels, and may often require the catheter to make sharp turns (e.g., 60 to 180 degree turns). Summary of the invention

[0003] The present invention describes an intravascular catheter having an optimal stiffness profile for traversing tortuous vessels.

[0004] One embodiment of the present invention has decreasing stiffness between its distal and proximal ends.

[0005] One embodiment of the present invention has a proximal section that exhibits uniform stiffness, a middle section that exhibits variable, decreasing stiffness, and a distal section that exhibits uniform stiffness.

[0006] One embodiment of the present invention has a higher stiffness in its proximal section than in its middle section, and a higher stiffness in its middle section than in its distal section.

[0007] One embodiment of the present invention includes an internal core wire. The core wire can be integrated along the axis of the catheter. The material and size distribution of the core wire can be adjusted to provide a desired stiffness distribution along the axis of the catheter. Using one or more core wires can reduce the need for polymer sheaths of different hardness or variable pitch braids.

[0008] The core wire may be used as a guide wire placed in a sheath of a catheter. Exemplary embodiments may include such an inner core wire fixed along at least a portion of the length of the coiled liner tube. In certain embodiments, the inner core wire may taper toward its distal end over at least a portion of its length.

[0009] The core wire may terminate at a point spaced distally relative to the distal end of the catheter. As an example, the core wire may terminate in a mid-section of an elongated member of the catheter; wherein the distal section of the elongated member remains more flexible due to the absence of the core wire. The distal section may account for approximately 10% to 12% of the length of the catheter.

[0010] In another embodiment of the invention, the core wire may not terminate in a tapered tip to avoid the risk of potential penetration or puncture of the outer sheath of the catheter. In such embodiments, the core wire may instead be coiled around an inner liner at the distal end of the core wire. In such embodiments, the core wire may have a uniform outer diameter, or may taper along at least a portion of its length.

[0011] In another embodiment of the present invention, multiple (e.g., two or more) core wires may be positioned and secured to the radially outer circumference of the liner tube. As an example, each of four core wires may be secured along the radial circumference of the liner tube at 90 degree increments, wherein each of the four core wires has a different length to impart a desired, decreasing stiffness profile along the length between the proximal and distal ends of the catheter. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] These and other aspects, features and advantages of embodiments of the present invention will become apparent and elucidated from the following description of embodiments of the present invention with reference to the accompanying drawings, in which

[0013] Figure 1 is a front view of an intravascular catheter according to one embodiment of the present invention.

[0014] Figure 2 1 is a partial front view of an intravascular catheter using a tapered core wire according to one embodiment of the present invention.

[0015] Figure 3 is a side view of an intravascular catheter using a tapered core wire according to one embodiment of the present invention.

[0016] Figure 4 It is along Figure 3 A cross-sectional view taken along line 4-4.

[0017] Figure 5 It is along Figure 3 A cross-sectional view taken along line 5-5.

[0018] Figure 6 is a partial front view of an intravascular catheter using a core wire with a coiled end according to one embodiment of the present invention.

[0019] Figure 7 is a side view of an intravascular catheter utilizing a core wire having a coiled end in accordance with one embodiment of the present invention.

[0020] Figure 8 is a longitudinal cross-sectional view cut in half along the length of a portion of an intravascular catheter according to one embodiment of the present invention.

[0021] Fig. 9 It is along Figure 7A sectional view taken along line 9-9.

[0022] Fig.10 1 is a partial front view of an intravascular catheter using multiple core wires according to one embodiment of the present invention.

[0023] Fig.11 is a side view of an intravascular catheter using multiple core wires according to one embodiment of the present invention.

[0024] Fig.12 is a longitudinal cross-sectional view cut in half along the length of a portion of an intravascular catheter according to one embodiment of the present invention.

[0025] Fig.13 It is along Fig.11 A cross-sectional view taken along line 13-13.

[0026] Fig.14A 2 is a view showing an intravascular catheter passing through a type II aortic arch according to one embodiment of the present invention.

[0027] Fig. 14B 2 is a view showing an intravascular catheter passing through a type III aortic arch according to one embodiment of the present invention.

[0028] Fig.15A is a graph comparing stiffness along a first range of distances from the distal end of an exemplary embodiment of the present invention.

[0029] Fig. 15B is a graph comparing stiffness along a second range of distances from the distal end of an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0030] Specific embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and should not be construed as being limited to the embodiments shown herein; on the contrary, providing these embodiments will make this disclosure thorough and complete and will fully convey the scope of the present invention to those skilled in the art. The terms used in the detailed description of the embodiments illustrated in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same numbers represent the same elements.

[0031] The terms "distal" and "proximal" are used in this specification. Unless otherwise defined, "distal" and "proximal" are relative to the physician during the procedure. Thus, "proximal" generally refers to closer to the physician, while "distal" generally refers to closer to the target location within the patient. However, the terminology is applicable whether the device is located within or outside the patient.

[0032] An exemplary embodiment of the intravascular catheter 100 may have a decreasing stiffness profile between the proximal end 104 and the distal end 105 to improve traversal in tortuous vessels. The intravascular catheter 100 may include a tubular elongated member 102 having a proximal section 102A, a middle section 102B, and a distal section 102C. A liner 107 may extend through the elongated member 102 to define a duct 103 (i.e., a lumen) within the elongated member 102.

[0033] The proximal section 102A may have a first stiffness, the middle section 102B may have a second stiffness, and the distal section 102C may have a third stiffness. The first stiffness may be greater than the second stiffness, and the second stiffness may be greater than the third stiffness. The first stiffness and the third stiffness may be uniform over their respective sections 102A, 102C, while the second stiffness may decrease (or increase) over at least a portion of the middle section 102B.

[0034] In one exemplary embodiment, a stiffness profile can be imparted to the elongated member 102 by using a core wire 110 fixed within and extending through the outer sheath 106 of the elongated member 102. The outer diameter of the core wire 110 can taper along its length, thereby gradually reducing the stiffness of the elongated member 102 between its proximal end 104 and distal end 105. The core wire 110 can terminate at the distal section 102C of the elongated member 102, or before the distal section 102C of the elongated member 102, so that the distal section 102C has greater flexibility than the proximal section 102A and the intermediate section 102B.

[0035] In an exemplary embodiment, the distal end 112 of the core wire 110 can be at least partially coiled around the outer circumference of the liner tube 107 to reduce or eliminate the possibility of the distal end 112 of the core wire 110 piercing or penetrating the elongated member 102 (e.g., the outer sheath 106 of the elongated member 102). The coiled portion 114 of the core wire 110 can be positioned at or before the distal segment 102C of the elongated member 102. In embodiments where the distal segment 102C of the elongated member 102 includes an enlarged portion 105A, the coiled portion 114 of the core wire 110 can be positioned before the proximal end of the enlarged portion 105A.

[0036] In another exemplary embodiment, a plurality of core wires 115A, 115B, 115C, 115D can each be fixed within and extend through the outer jacket 106 of the elongated member 102. The respective lengths of the core wires 115A, 115B, 115C, 115D can be staggered so that each core wire 115A, 115B, 115C, 115D has a different length. In this manner, the stiffness of the elongated member 102 can be gradually reduced along its length. The core wires 115A, 115B, 115C, 115D can be positioned radially around the outer circumference of the liner tube 107. In some embodiments, each core wire 115A, 115B, 115C, 115D can include a first material 116 and a second material 117 connected to the first material 116; the first material 116 is harder than the second material 117.

[0037] Figure 1 An example of an intravascular catheter 100 is shown. The methods and systems described herein can be used with multiple types of catheters 100 and should not be construed as being limited to any particular type or configuration of catheters. The catheter 100 may include 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" can be used. U.S. Patents No. 10,682,493 and 10,456,552 are both incorporated herein by reference in their entirety.

[0038] Figure 1 The illustrated exemplary embodiment of the intravascular catheter 100 may include a connector 101 and an elongated member 102 connected to and extending from the connector 101. The connector 101 may include a channel 101A that may be fluidly connected to a conduit 103 of the catheter 100 so that various tools or devices may be inserted into the conduit 103 through the channel 101A. Thus, the channel 101A of the connector 101 may be coaxial with the conduit 103 of the elongated member 102.

[0039] The elongated member 102 may include a proximal end 104 connected to the connector 101 and a distal end 105 opposite the proximal end 104. The elongated member 102 may include an enlarged portion 105A at or near its distal end 105. The enlarged portion 105A may include a larger diameter than the remainder of the elongated member 102. The enlarged portion 105A may be located exclusively within the distal section 102C, and thus the enlarged portion 105A may not extend into the proximal section 102A or the middle section 102B.

[0040] The elongated member 102 may include an outer sheath 106 constructed of various flexible materials including various polymer materials. Non-limiting examples of such polymer materials for forming the outer sheath 106 may include thermoplastics such as PEBAX, PET, polytetrafluoroethylene (PTFE), polyimide, composite materials, etc. The thickness and density of the outer sheath 106 may vary in different embodiments to accommodate different applications, but the thickness and density of the outer sheath 106 should be considered when designing an optimal stiffness distribution because the outer sheath 106 contributes to the overall stiffness of the catheter 100.

[0041] The outer sheath 106 of the elongated member 102 may have different outer diameters along the length of the elongated member 102. For example, Figures 2 to 3 and Figures 5 to 7 In the exemplary embodiment shown, it can be seen that the outer jacket 106 of the elongated member 102 may include a first section 106A having a first outer diameter, a second section 106B having a second outer diameter, and a third section 106C having a third outer diameter.

[0042] The first outer diameter may be greater than the second outer diameter, and the second outer diameter may be greater than the third outer diameter. In the illustrated embodiment, the first section 106A of the outer sheath 106 may have a uniform first outer diameter, the second section 106B of the outer sheath 106 may have a gradually decreasing (i.e., decreasing) second outer diameter, and the third section 106C of the outer sheath 106 may have a uniform third outer diameter.

[0043] Continue to refer Figures 2 to 3 and Figures 5 to 7 , it can be seen that the elongated member 102 can taper from a larger diameter to a smaller diameter only along the first radial edge. For example, the top of the elongated member 102 can be tapered, wherein the bottom of the elongated member 102 extends linearly without any taper.

[0044] A liner tube 107 can extend through the elongated member 102 to define the conduit 103, and the diameter of the liner tube 107 can be smaller than the diameter of the elongated member 102 through which it extends. The conduit 103 can extend through the liner tube 107. In this manner, the elongated member 102 can define an outer tube, and the liner tube 107 can define an inner tube extending through the outer tube.

[0045] In different embodiments, the positioning of the conduit 103 within the elongated member 102 may vary. For example, Figure 4 and Figure 5 An exemplary embodiment is shown in which the inner liner tube 107 can extend through the lower half of the height of the outer jacket 106 of the elongated member 102. In other words, the conduit 103 can be positioned below the longitudinal axis extending through the center of the elongated member 102. Fig. 9 and Fig.13 An exemplary embodiment is shown in which the conduit 103 may be centrally positioned within the elongated member 102 .

[0046] In different embodiments, the corresponding diameters of the elongated member 102 and the tube 103 and the ratio therebetween can be varied to suit different applications. Therefore, the corresponding sizes of the elongated member 102 and the tube 103 and the ratio therebetween should not be interpreted as being limited to the exemplary embodiments illustrated in the drawings.

[0047] The length of the liner 107, and therefore the length of the conduit 103, can be equal to the length of the elongated member 102, although in some embodiments, the length of the liner 107 can be greater or less than the length of the elongated member 102. The liner 107 can be secured within the elongated member 102 such that the liner 107 cannot be removed from the elongated member 102. The liner 107 can be coiled as shown in the figures, with the coiling wire 108 coiled around at least a portion of the length of the liner 107. In different embodiments, the pitch of the coiling wire 108 can vary. The pitch of the coiling wire 108 can be uniform over the length of the liner 107, or can vary along different portions of the length of the liner 107.

[0048] like Figure 1 As shown, the elongated member 102 of the catheter 100 may include a proximal section 102A, an intermediate section 102B, and a distal section 102C. The proximal section 102A may include a first length of the elongated member 102 between its proximal end 104 and the intermediate section 102B. The intermediate section 102B may include a second length of the elongated member 102 positioned between the proximal section 102A and the distal section 102C. The distal section 102C may include a third length of the elongated member 102 between the intermediate section 102B and the distal end 105 of the elongated member 102.

[0049] In such Figure 1 In the exemplary embodiment shown, the distal end 105 of the elongated member 102 may include an enlarged portion 105A having a larger diameter than the remainder of the elongated member 102 (e.g., the proximal section 102A and the intermediate section 102B), although in some embodiments, such as Fig.14A and Fig. 14B As shown, the enlarged portion 105A may be omitted.

[0050] In different embodiments, the length of each of the segments 102A, 102B, 102C may vary. In the various illustrated embodiments shown in the figures, the length of the proximal segment 102A may be greater than the length of the middle segment 102B. The length of the distal segment 102C may be greater than the length of the middle segment 102B.

[0051] In different embodiments, the ratio of the respective lengths of the different sections 102A, 102B, 102C can vary. In an exemplary embodiment, the sum of the lengths of the proximal section 102A, the middle section 102B, and the distal section 102C, and thus the overall length of the elongated member 102, can be between 150 and 165 centimeters. However, such dimensions are for exemplary purposes only, as the elongated member 102 can be longer or shorter, depending on the application in which the catheter 100 is used.

[0052] In one exemplary embodiment, the length of the intermediate section 102B measured between the proximal section 102A and the distal section 102C can be between 6 and 16 centimeters. The length of the distal section 102C measured from the distal end 105 to the proximal end 104 of the elongated member 102 can be between 12 and 26 centimeters. Thus, in one exemplary embodiment, the length of the distal section 102C can be between about 7% and 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 between 150 cm and 165 cm, and the length of the distal segment 102C measured from the distal end 105 of the elongated member 102 to the proximal end 104 of the elongated member 102 may be between 15 cm and 20 cm, and as described below, the core wire 110 may not extend into the distal segment 102C. In another exemplary embodiment, the combined length of the proximal segment 102A, the intermediate segment 102B, and the distal segment 102C may be 165 cm, and the length of the distal segment 102C may be 16.5 cm.

[0054] It has been found that the specific length of the distal segment 102C has greater flexibility than the proximal segment 102A and the middle segment 102B, and such dimensions provide an optimal stiffness distribution for traversing tortuous blood vessels. For example, the increased flexibility (and therefore reduced stiffness) of the last 7% to 16% of the length of the slender member 102 ensures that the distal segment 102C can be easily manipulated to pass through sharp turns in the blood vessel. By omitting the core wire 110 in the last 7% to 16% of the length of the slender member 102, the distal end 105 of the slender member 102 can have greater flexibility to hook around or otherwise traverse tortuous blood vessels with sharp turns.

[0055] Each of the foregoing lengths is for illustrative purposes only and should not be construed as limiting in scope, as different lengths (and ratios between lengths) may be used in different embodiments to accommodate different applications and processes.

[0056] The elongated member 102 of the catheter 100 may have a uniform diameter over its length, or may be elongated, for example. Figures 2 to 3 and Figure 6 to Figure 7 In some exemplary embodiments shown in , the elongated member 102 of the catheter 100 may taper along one or more sections 102A, 102B, 102C of its length. Thus, for example Figure 1 , Fig.14A and Fig. 14B The uniform diameter of the elongated member 102 shown in FIG. 1 should not be construed as limiting the range.

[0057] At least Figures 2 to 3 and Figures 5 to 7 In the exemplary embodiment shown, it can be seen that the elongated member 102 of the catheter 100 can be tapered along at least a portion of the length of the intermediate section 102B. In such embodiments, the outer sheath 106 of the elongated member 102 can include a series of first, second, and third sections 106A, 106B, 106C, each section having a different outer diameter; wherein the first section 106A has a uniform first outer diameter, the second section 106B has a gradually decreasing second outer diameter that can be smaller than the first outer diameter, and the third section 106C has a uniform third outer diameter that can be smaller than the first outer diameter and the second outer diameter.

[0058] In some embodiments, the diameter of the elongated member 102 can continue to taper along at least a portion of the length of the distal segment 102C. In some embodiments, the intermediate segment 102B of the elongated member 102 can taper, and the proximal segment 102A and the distal segment 102B of the elongated member 102 can be of uniform diameter. In further exemplary embodiments, the proximal segment 102A of the elongated member 102 can be of uniform diameter, and both the intermediate segment 102B and the distal segment 102C can taper. In further exemplary embodiments, the distal segment 102C can include an expanded portion 105A as discussed herein, wherein the expanded portion 105A has a larger diameter than any other portion of the elongated member 102.

[0059] The intravascular catheter 100 generally has an optimal stiffness distribution for passing through a tortuous vessel (e.g., a type II or type III aortic arch). The intravascular catheter 100 may have a variable stiffness distribution between its proximal end 104 and distal end 105. Each of the respective segments 102A, 102B, 102C may have a different stiffness. The distal segment 102C may have a smaller stiffness (i.e., greater flexibility) than the proximal segment 102A and the intermediate segment 102B, so that the distal segment 102C may be easily hooked, bent, or otherwise manipulated to make a sharp turn through a tortuous vessel.

[0060] In an exemplary embodiment, the stiffness of the intravascular catheter 100 can decrease (e.g., taper) between the proximal end 104 and the distal end 105 of the elongated member 102. In such exemplary embodiments, the rate at which the stiffness of the intravascular catheter 100 decreases can be uniform over its length. In another exemplary embodiment, the rate at which the stiffness of the intravascular catheter 100 decreases can be variable, e.g., having a portion with uniform stiffness and a portion with gradually decreasing stiffness.

[0061] In an exemplary embodiment, the intravascular catheter 100 can have a first stiffness along the length of the proximal segment 102A. The first stiffness of the elongated member 102 along the length of the proximal segment 102A can be uniform (i.e., consistent over the length of the proximal segment 102A). However, in other embodiments, the first stiffness can increase or decrease along the proximal segment 102A of the intravascular catheter 100. The proximal segment 102A can include a proximal length of the elongated member 102 extending from the proximal end 104 and terminating at the intermediate segment 102B.

[0062] In an exemplary embodiment, the intravascular catheter 100 can have a second stiffness along the length of the middle section 102B. The second stiffness can be less than the first stiffness. Therefore, the stiffness of the middle section 102B can be less than the stiffness of the proximal section 102A, so that the stiffness of the elongated member 102 is reduced between the proximal section 102A and the middle section 102B. The second stiffness on the middle section 102B can be uniform, or the second stiffness can be reduced (or increased) at various rates along the length of the middle section 102B. The middle section 102B can include the middle length of the elongated member 102 between the proximal end 104 and the distal end 105. The middle section 102B can include the length of the elongated member 102 extending from the proximal section 102A to the distal section 102C (i.e., the middle section 102B extends between the proximal section 102A and the distal section 102C of the elongated member 102).

[0063] In an exemplary embodiment, the intravascular catheter 100 can have a third rigidity along the length of the distal section 102C. The third rigidity can be less than the second rigidity. Therefore, the rigidity of the distal section 102C can be less than the rigidity of each in the proximal section 102B and the intermediate section 102C. The third rigidity of the intravascular catheter 100 on the distal section 102C can be uniform (that is, the length of the distal section 102C is consistent), or the third rigidity can be reduced (or increased) at various rates along the length of the distal section 102C. The distal section 102C can include the distal length of the elongated member 102 extending from the intermediate section 102B and terminating at the distal end 105.

[0064] In different embodiments, the manner in which the desired stiffness distribution of the intravascular catheter 100 is achieved can vary. In a first exemplary embodiment, the core wire 110 can be connected to the intravascular catheter 100 in a fixed manner to impart a desired stiffness distribution to the catheter 100. Thus, the core wire 110 can extend through the intravascular catheter 100 in a non-removable manner. For example, the core wire 110 can be integrated into the outer sheath 106 of the elongated member 102. The core wire 110 can extend through a lumen in the elongated member 102 that is separate and distinct from the conduit 103 of the elongated member 102. The lumen of the elongated member 102 through which the core wire 110 extends can be parallel to the conduit 103 of the elongated member 102. In some embodiments, the core wire 110 can be connected to the liner tube 107 at one or more points along the length of the core wire 110, or continuously connected to the liner tube 107 along its length.

[0065] The stiffness of the intravascular catheter 100 can be the sum of the stiffness of the outer sheath 106, the inner liner 107, and the core wire 110. Therefore, the core wire 110 can be configured to achieve a desired stiffness for passing through a tortuous blood vessel in different embodiments. In some embodiments, the core wire 110 can terminate at the distal end of the middle section 102B (i.e., the core wire 110 terminates at the beginning of the distal section 102C). In such embodiments, the stiffness of the distal section 102C can be the sum of the stiffness of the outer sheath 106 and the coiled inner liner 107 because the core wire 110 is not present in the distal section 102C.

[0066] In the exemplary embodiment shown in the figures, a desired stiffness profile of the intravascular catheter 100 can be achieved by using a core wire 110 that extends at least partially through the intravascular catheter 100. In an exemplary embodiment, the core wire 110 can taper along at least one of the segments 102A, 102B, 102C of the elongated member 102. In another exemplary embodiment, the core wire 110 can transition into a coiled portion 114 such that the distal end 112 of the core wire 110 is coiled around the conduit 103. In other embodiments, multiple core wires 115A, 115B, 115C, 115D of different lengths and / or materials 116, 117 can extend through the intravascular catheter 100; the multiple core wires 115A, 115B, 115C, 115D are positioned outside of the liner tube 107.

[0067] In embodiments where the core wire 110 tapers along at least a portion of its length, the length and degree of taper may vary in different embodiments. In one exemplary embodiment, the core wire 110 has a uniform outer diameter along the proximal section 102A and tapers along the middle section 102B. In one exemplary embodiment, at the middle section 102B, the outer diameter of the distal end 112 of the core wire 110 (e.g., after the tapered portion thereof) may be between 12% and 14% of the starting outer diameter of the core wire 110 at the proximal section 102A.

[0068] For example, the outer diameter of the core wire 110 along the proximal section 102A can be between 0.05 and 0.07 centimeters. The outer diameter of the core wire 110 can then taper to an outer diameter between 0.007 and 0.008 centimeters along the middle section 102B. The tapering length of the outer diameter of the core wire 110 can be between 7 and 16 centimeters. It has been found that such a configuration is well suited for passing through sharp turns in tortuous blood vessels.

[0069] Each of the foregoing dimensions is for illustrative purposes only and should not be construed as limiting in scope, as different lengths and degrees of taper may be used in different embodiments of the core wire 110 to accommodate different applications.

[0070] The one or more materials 116, 117 of the core wire 110 may vary in different embodiments. In one exemplary embodiment, the core wire 110 may be stainless steel. In another exemplary embodiment, the core wire 110 may be a nickel-titanium alloy (i.e., Nitinol). In yet another exemplary embodiment, the core wire 110 may include stainless steel and Nitinol.

[0071] In some embodiments, the core wire 110 may include stainless steel and nitinol. For example, the core wire 110 along the proximal section 102A may be composed of stainless steel, and the core wire 110 along the middle section 102B may be composed of nitinol. Such an arrangement allows the proximal end 104 to have greater rigidity and the distal end 105 to have greater flexibility.

[0072] The core wire 110 will generally be integrated 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 such that the core wire 110 is not removable. As shown in the figures, the core wire 110 may be fixed or positioned on the liner 107 (e.g., at the outer circumference of the pipe 103), but in some embodiments, the core wire 110 may instead extend parallel to the liner 107 without contacting the liner 107.

[0073] In embodiments where the core wire 110 can be secured against the inner liner 107, the manner in which the core wire 110 is secured to the inner liner 107 can vary. While an adhesive (e.g., glue) can be used to secure the core wire 110 to the inner liner 107, the adhesive generally affects the stiffness profile of the elongated member 102, and this must be considered in such embodiments. In one exemplary embodiment, heat shrink tubing can be used to secure the core wire 110 to the inner liner 107 and to secure the inner liner 107 within the outer jacket 106. In such preferred embodiments, a mandrel or the like can be inserted into the inner liner 107 to hold the pipe 103 while the heat shrink tubing is applied.

[0074] Figures 2 to 5An exemplary embodiment of an intravascular catheter 100 is shown, which has a decreasing stiffness distribution between its proximal end 104 and distal end 105. In the illustrated embodiment, an elongated core wire 110 can extend through the intravascular catheter 100. The core wire 110 can be fixed on the pipe 103 (e.g., the outer circumference of the inner liner 107) or in contact with the pipe 103 (e.g., the outer circumference of the inner liner 107). In an exemplary embodiment, the core wire 110 can be fixed at the upper end of the outer circumference of the inner liner 107. However, in other embodiments, the core wire 110 can be fixed at different other radial positions (e.g., the bottom or side) of the outer circumference of the inner liner 107. In other embodiments, the core wire 110 may not be fixed on the inner liner 107 or in contact with the inner liner 107, but can extend parallel to the inner liner 107 within the outer sheath 106.

[0075] The length of the core wire 110 can be the same as the elongated member 102, or it can be longer or shorter than the elongated member 102. In an exemplary embodiment, the proximal end of the core wire 110 can extend out of the proximal end 104 of the elongated member 102 and into the channel 101A of the connector 101. In an exemplary embodiment, approximately one centimeter of the length of the core wire 110 can extend through the proximal end 104 of the elongated member 102 and into the channel 101A of the connector 101 of the catheter 100. Such a configuration ensures that the physician's manipulation of the connector 101 is also transmitted to the core wire 110.

[0076] In the exemplary embodiment of the figures, the core wire 110 is shown as including a uniform outer diameter along the length of the proximal section 102A of the elongated member 102. The outer diameter of the core wire 110 along the proximal section 102A of the elongated member 102 may include various sizes. In an exemplary embodiment, the outer diameter may be between 0.05 and 0.07 centimeters.

[0077] Thus, the core wire 110 may have a first stiffness along the proximal section 102A of the elongated member 102. The core wire 110 may maintain the same outer diameter, and therefore the same stiffness, along the entire length of the proximal section 102A of the elongated member 102 from the proximal end 104 to the intermediate section 102B.

[0078] like Figure 2 and Figure 3As best shown in FIG. 1 , the core wire 110 may include a tapered portion 113 having a decreasing outer diameter (i.e., tapered) for its length along the intermediate section 102B of the elongated member 102. The rate at which the outer diameter of the tapered portion 113 of the core wire 110 decreases along the intermediate section 102B (e.g., the amount of outer diameter decrease per unit length) may vary in different embodiments and should not be construed as being limited to the exemplary embodiments shown in the figures. For example, Figures 2 to 3 The tapered portion 113 as shown may extend the entire length of the intermediate section 102B, or in other embodiments may extend to a length that is less than or greater than the length of the intermediate section 102B.

[0079] exist Figure 2 and Figure 3 In the illustrated embodiment, the core wire 110 may terminate at a distal end 112 at the transition between the intermediate section 102B and the distal section 102C of the elongated member 102. Thus, the distal end 112 of the core wire 110 may terminate before the start of the enlarged portion 105A of the elongated member 102, such that the enlarged portion 105A has sufficient flexibility to navigate through sharp turns in tortuous blood vessels.

[0080] The outer diameter of the distal end 112 of the core wire 110 can be smaller than the outer diameter of the core wire 110 along the proximal section 102A of the slender member 102. As an example, the outer diameter of the distal end 112 of the core wire 110 can be between 12% and 14% of the outer diameter of the core wire 110 along the proximal section 102A of the slender member 102. In an exemplary embodiment, the outer diameter of the distal end 112 of the core wire 110 can be between 0.007 and 0.008 centimeters. Such a configuration ensures that the stiffness of the core wire 110 gradually decreases along the length of the slender member 102 to provide an optimal stiffness distribution for traversing through tortuous blood vessels including sharp turns.

[0081] Continue to refer Figure 2 and Figure 3 , it can be seen that the core wire 110 may not extend into the distal segment 102C of the elongated member 102. Such a configuration ensures flexibility of the distal segment 102C and the distal end 105 of the elongated member 102 to allow for the manipulation necessary to traverse a tortuous vessel (e.g., through the aortic arch). Thus, in such embodiments, the core wire 110 may not contribute any stiffness to the distal segment 102C of the elongated member 102, wherein the total stiffness of the distal segment 102C is the sum of the stiffness of the outer sheath 106 and the inner liner 107 (including any coiling wire 108 coiled around the inner liner 107).

[0082] Figure 4 and Figure 5 A cross-sectional view of the elongated member 102 is shown to illustrate both the liner tube 107 and the core wire 110 . Figure 4 is within the proximal section 102A of the elongated member 102 along Figure 3 A cross-sectional view taken along line 4-4 of FIG. Figure 4 As shown, the outer diameter of the core wire 110 may be approximately the same as the outer diameter of the liner tube 107. However, it should be understood that in other exemplary embodiments, the outer diameter of the core wire 110 may be larger or smaller than the outer diameter of the liner tube 107 to achieve different desired stiffness profiles.

[0083] refer to Figure 4 , it can be seen that tubing 103, and therefore liner tube 107, can be positioned below a longitudinal axis extending through the center of elongated member 102 along at least a portion of the length of elongated member 102. Similarly, it can be seen that core wire 110 can be positioned above a longitudinal axis extending through the center of elongated member 102. Such a configuration can improve traversal through tortuous vessels having sharp turns.

[0084] Figure 5 It is along Figure 3 5, which is located at the end of the intermediate section 102B of the slender member 102, and therefore at the distal end 112 after the tapered portion of the core wire 110. Figure 5 As shown, the outer diameter of the distal end 112 of the core wire 110 can be smaller than the outer diameter of the inner liner 107. In an exemplary embodiment, the outer diameter of the distal end 112 of the core wire 110 can be approximately 12% to 14% of the outer diameter of the inner liner 107. Figure 5 It can also be seen in FIG. 1 that the outer jacket 106 of the elongated member 102 may also taper inwardly along the length of the second section 106B thereof to match the taper of the core wire 110 along the intermediate section 102B.

[0085] Figures 6 to 9 An exemplary embodiment of an intravascular catheter 100 is shown having a decreasing stiffness profile between its proximal end 104 and distal end 105. As with the previous embodiments, an elongated core wire 110 may extend through the intravascular catheter 100. The core wire 110 may be fixed to the outer circumference of the tubing 103, such as by being fixed to the outer circumference of the liner tube 107. Although the figures show the core wire 110 fixed to or in contact with the upper end of the outer circumference of the liner tube 107, in other embodiments, the core wire 110 may be fixed to or in contact with different other radial positions of the outer circumference of the liner tube 107. In other embodiments, the core wire 110 may not be in contact with or fixed to the liner tube 107, but may extend parallel to the liner tube 107 within the outer sheath 106.

[0086] As with the previous embodiments, the core wire 110 can include a uniform outer diameter along the length of the core wire 100 of the proximal section 102A of the elongated member 102. Various outer diameters can be used in different embodiments to accommodate different applications and to exhibit different desired stiffness profiles. In an exemplary embodiment, the outer diameter of the core wire 110 along the proximal section 102A can be between 0.05 cm and 0.07 cm.

[0087] Figures 6 to 9 The core wire in the illustrated embodiment may have a uniform first stiffness along the proximal section 102A of the elongated member 102. Figures 6 to 9 The illustrated core wire 110 may maintain the same outer diameter and the same stiffness along the entire length of the proximal section 102A of the elongated member 102 from the proximal end 104 to the intermediate section 102B.

[0088] like Figure 6 and Figure 7 As best shown in FIG. 1 , at least a portion of the length of the core wire 110 along the middle section 102B of the elongated member 102 can have a decreasing outer diameter (i.e., be tapered). The rate of decrease in the outer diameter of the core wire 110 along the middle section 102B can vary in different embodiments and should not be construed as being limited to the exemplary embodiments shown in the figures.

[0089] In e.g. Figure 6 and Figure 7 In the exemplary embodiment shown, the core wire 110 may include a first section 113A having a first uniform outer diameter. The first section 113A of the core wire 110 having a first uniform outer diameter may extend from the proximal end 104 of the elongated member 102 to the length of the proximal section 102A of the elongated member 102; terminating at the middle section 102B of the elongated member 102.

[0090] The core wire 110 may include a second section 113B having a second tapered outer diameter, in which the outer diameter of the core wire 110 may gradually decrease. The second section 113B may extend as a portion of the intermediate section 102B. In different embodiments, the degree of tapering (ie, the rate and amount of decrease in outer diameter) may vary.

[0091] The core wire 110 may include a third section 113C having a third uniform outer diameter. The third section 113C may extend as a portion of the intermediate section 102B. For example, as shown in the figure, the third section 113C may terminate in a coiled portion 114 in which the distal end 112 of the core wire 110 is coiled around the liner tube 107. In various embodiments, the coiled portion 114 may have a spiral shape that extends around the outer circumference of the liner tube 107 with varying numbers of coils.

[0092] The first section 113A, the second section 113B and the third section 113C of the core wire 110 may be integrally formed. The third uniform outer diameter of the third section 113C may be smaller than the first uniform outer diameter of the first section 113A. The second tapered outer diameter of the second section 113B may gradually decrease from the first uniform outer diameter to the third uniform outer diameter.

[0093] Therefore, it can be seen that when the core wire 110 extends through the middle section 102B of the slender member 102, the core wire 110 may include a gradually tapering second section 113B and a uniform third section 113C, wherein the second section 113B has a gradually decreasing outer diameter, and the uniform outer diameter of the third section 113C is smaller than the outer diameter of the first section 113A of the core wire 110 in the proximal section 102A of the slender member 102.

[0094] In various embodiments, the respective lengths of the tapered second section 113B and the uniform third section 113C of the core wire 110 may vary as they extend along the middle section 102B of the elongated member 102. In some embodiments, as discussed below, the core wire 110 may taper over the entire length of the middle section 102B of the elongated member 102 before terminating in the coiled portion 114. In such embodiments, the uniform third section 113C may be omitted. In other embodiments, the core wire 110 may maintain a uniform outer diameter over the entire length of the middle section 102B of the elongated member 102 before terminating in the coiled portion 114.

[0095] like Figures 6 to 8 As shown, the core wire 110 may terminate in a coiled portion 114 in which the distal end 112 of the core wire 110 is coiled around the inner liner 107. Such an embodiment may be desirable to eliminate the risk of the distal end 112 of the core wire 110 penetrating through the outer sheath 106 of the elongated member 102 and injuring the patient (e.g., when making a sharp turn). By coiling the core wire 110 around the inner liner 107, the risk of the distal end 112 of the core wire 110 piercing or penetrating the elongated member 102 is significantly reduced.

[0096] refer to Figure 6 to Figure 7 , it can be seen that the core wire 110 may not extend into or through any portion of the distal segment 102C of the elongated member 102. Therefore, the distal segment 102C of the elongated member 102 may have greater flexibility (i.e., less stiffness) than both the proximal segment 102A and the middle segment 102B. Such a configuration may help make common sharp turns when traversing tortuous vessels such as those found in a typical aortic arch.

[0097] In the exemplary embodiment shown in the accompanying drawings, it can be seen that the coiled portion 114 of the core wire 110 can include approximately three coils around the inner liner 107. However, it should be understood that in different embodiments, the coiled portion 114 can include more or fewer coils. In addition, it should be understood that the pitch of the coiled portion 114 can vary in different embodiments and should not be construed as limited to the exemplary embodiments shown in the accompanying drawings. In addition, while the accompanying drawings show the coiled portion 114 having the same outer diameter as the uniform third section 113C of the coiled wire 110, in some embodiments, the coiled portion 114 can taper as it coils around the inner liner 107.

[0098] Figure 8 A longitudinal cross-sectional view is shown cut in half along the length of a portion of the elongated member 102. In the exemplary embodiment shown, it can be seen that the core wire 110 can be secured to or in contact with the top of the liner tube 107 before terminating in a coiled portion 114 that is coiled around the liner tube 107. In other embodiments, the core wire 110 can extend at other radial locations along the outer circumference of the liner tube 107, not just the top.

[0099] Fig. 9 It is along Figure 7 A cross-sectional view taken along line 9-9 of FIG. Fig. 9 As shown, the coiled portion 114 can be completely coiled around the inner liner 107 so as to terminate the coiled wire 110 without forming a sharp point or leaving an exposed linear distal end 112, which may pierce or penetrate the outer sheath 106 of the slender member 102. However, in some embodiments, the coiled portion 114 can only be coiled partially around the inner liner 107 (e.g., the coiled portion 114 can be less than a complete turn). For example, in some embodiments, the coiled portion 114 can only be coiled around approximately half of the outer circumference of the inner liner 107, and thus only have half a turn.

[0100] Figures 10 to 13 A third exemplary embodiment of an intravascular catheter 100 is shown having multiple core wires 115A, 115B, 115C, 115D rather than a single core wire 110. Such an embodiment may utilize core wires 115A, 115B, 115C, 115D, each of which has a uniform outer diameter over its length, rather than tapering. However, in some exemplary embodiments, one or more of the core wires 115A, 115B, 115C, 115D may taper along at least a portion of their respective lengths.

[0101] In the illustrated embodiment, each of the four core wires 115A, 115B, 115C, 115D extends through the intravascular catheter 100. It should be understood that more or fewer core wires 115A, 115B, 115C, 115D may be used in different embodiments to achieve a desired stiffness distribution. For example, in an exemplary embodiment, only two core wires 115A, 115B may be used. In other embodiments, three, five, or more core wires 115A, 115B, 115C, 115D may be used.

[0102] Each of the core wires 115A, 115B, 115C, 115D is shown as being fixed to or in contact with the outer circumference of the inner liner tube 107. Fig.10 and Fig.13 In the illustrated exemplary embodiment best shown in FIG. 1 , a first core wire 115A may be secured on or in contact with a top portion of the liner 107, a second core wire 115B may be secured on or in contact with a first side of the liner 107, a third core wire 115C may be secured on or in contact with a bottom portion of the liner 107, and a fourth core wire 115D may be secured on or in contact with a second side of the liner 107. In other embodiments, one or more of the core wires 115A, 115B, 115C, 115D may not be secured on or in contact with the liner 107, but may instead extend parallel to the liner 107 within the outer jacket 106.

[0103] In the embodiment shown in the figures, each of the core wires 115A, 115B, 115C, 115D can be radially positioned at equal distances relative to each other around the outer circumference of the liner tube 107. More specifically, it can be seen that each of the core wires 115A, 115B, 115C, 115D can be spaced 90 degrees from adjacent core wires 115A, 115B, 115C, 115D. However, in certain embodiments, the spacing of the core wires 115A, 115B, 115C, 115D around the outer circumference of the liner tube 107 can vary. For example, two or more of the core wires 115A, 115B, 115C, 115D can be grouped more closely together.

[0104] like Figures 10 to 12As best shown in FIG. 1 , each of the core wires 115A, 115B, 115C, 115D can have a different length. The different lengths of the core wires 115A, 115B, 115C, 115D can gradually reduce or step down the stiffness of the catheter 100 over the middle section 102B of the elongated member 102. Thus, by terminating each core wire 115A, 115B, 115C, 115D at a different location along the middle section 102B, the effective stiffness can be gradually reduced before the last core wire 115A, 115B, 115C, 115D terminates at the beginning of the distal section 102C.

[0105] exist Fig.10 In the exemplary embodiment shown, the third core wire 115C can be longer than each of the first core wire 115A, the second core wire 115B, and the fourth core wire 115D, the fourth core wire 115D can be longer than each of the first core wire 115A and the second core wire 115B, and the first core wire 115A can be longer than the second core wire 115B. However, such a configuration is shown as an exemplary embodiment only, as various other alternative arrangements can be utilized in different embodiments.

[0106] Although the figures show that each of the core wires 115A, 115B, 115C, 115D has a different length relative to each other, in some embodiments, two or more of the core wires 115A, 115B, 115C, 115D may have the same length. In addition, the positioning of the longest and shortest core wires 115A, 115B, 115C, 115D shown in the figures is for illustrative purposes only and should not be interpreted as limiting the scope. For example, the figures show that the third core wire 115C, which can extend along the bottom of the liner 107 and be fixed to the bottom of the liner 107, is the longest of the core wires 115A, 115B, 115C, 115D, and the first core wire 115A, which can extend along the top of the liner 107 and be fixed to the top of the liner 107, is the shortest of the core wires 115A, 115B, 115C, 115D. However, in different embodiments, the opposite configuration or various other configurations may be used instead.

[0107] To further help control the stiffness profile of the catheter 100, one or more of the core wires 115A, 115B, 115C, 115D may include different materials. The figures show that each of the core wires 115A, 115B, 115C, 115D is composed of two materials 116, 117. The first material 116 that forms the proximal length of each core wire 115A, 115B, 115C, 115D may be a harder or more rigid material, such as stainless steel. The second material 117 may be connected to the distal end of the first material 116 to form a single core wire 115A, 115B, 115C, 115D and may form the distal length of each core wire 115A, 115B, 115C, 115D, and the second material 117 may be a less rigid (i.e., more flexible) material, such as Nitinol.

[0108] In different embodiments, the length of the respective material 116, 117 for each core wire 115A, 115B, 115C, 115D may vary. Although the figures show that the second material 117 may include a shorter length of each core wire 115A, 115B, 115C, 115D than the first material 116, the opposite may be true in some embodiments. In another exemplary embodiment, the lengths of the respective first and second materials 116, 117 may be equal. In some embodiments, the entirety of each core wire 115A, 115B, 115C, 115D may include a single material 116, 117. In other embodiments, three or more materials may be fused together to form each core wire 115A, 115B, 115C, 115D.

[0109] Fig.12 is a longitudinal cross-sectional view cut in half along the length of a portion of the elongated member 102. In the illustrated embodiment, the first core wire 115A is shown as being fixed to and extending along the top of the liner tube 107, and the third core wire 115C is shown as being fixed to and extending along the bottom of the liner tube 107. The corresponding dimensions of the core wires 115A, 115B, 115C, 115D and the liner tube 107 may vary from those shown in the figures in different embodiments.

[0110] Fig.13 It is along Fig.11 A cross-sectional view taken along line 13-13 of FIG. Fig.13As shown, each of the four core wires 115A, 115B, 115C, 115D can be radially positioned around the outer circumference of the inner liner 107. The core wires 115A, 115B, 115C, 115D can be directly fixed to or in contact with the inner liner 107, or can alternatively be disposed within the outer jacket 106 in a fixed manner parallel to the inner liner 107 but not in contact with the inner liner 107. Since this view is only for illustrative examples, it should be understood that the ratio between the diameter of the core wires 115A, 115B, 115C, 115D and the diameter of the inner liner 107 can vary in different embodiments.

[0111] Fig.14A and Fig. 14B An exemplary intravascular catheter 100 is shown traversing or passing through the aortic arch. Fig.14A A type II aortic arch is shown, and Fig. 14B A type III aortic arch is shown. Fig.14A and Fig. 14B , and it should be understood that such an intravascular catheter 100 may include an enlarged portion 105A or sections 106A, 106B, 106C of its outer sheath 106 having different outer diameters, as previously discussed.

[0112] In operation, the intravascular catheter 100 can pass upward through the descending aorta and through the aortic arch. Then, the intravascular catheter 100 can make a sharp turn to the right to enter the brachiocephalic artery. The catheter 100 can have a more flexible distal section 102C to allow the distal section 102C of the catheter 100 and therefore the distal end 105 to pass through such a sharp turn more easily. As shown in the illustrated embodiment, the intravascular catheter 100 can continue to enter the right common carotid artery.

[0113] The optimal stiffness profile of the intravascular catheter 100 (in which the stiffness of the catheter 100 can decrease along its length between its proximal end 104 and distal end 105 and can include a flexible distal section 102C) can allow a physician to more easily and efficiently navigate the catheter 100 through the aortic arch while reducing or eliminating the risk of the catheter 100 rebounding into the ascending aorta. Although the accompanying drawings illustrate a path through the aortic arch and into the right common carotid artery, it should be understood that the systems and methods described herein can be used for various other paths. For example, the catheter 100 can alternatively be guided through the right subclavian artery, the left common carotid artery, or the left subclavian artery; each of these paths is made possible due to the unique and optimal stiffness profile of the catheter 100.

[0114] Fig.15A and Fig. 15BAn exemplary graph comparing stiffness at different ranges of distances along the distal end 105 of an exemplary embodiment of the catheter 100 is shown. Both figures compare load values ​​(in grams-force (GF)) versus distance from the distal end 105 of an exemplary embodiment of the catheter 100 (in centimeters (cm)). Fig.15A Load values ​​(unit: GF) ranging from 0 cm to 40 cm from the distal end 105 of an exemplary embodiment of the catheter 100 are shown. Fig. 15B Load values ​​(unit: GF) ranging from 12 cm to 26 cm from the distal end 105 of an exemplary embodiment of the catheter 100 are shown.

[0115] like Fig.15A As shown, the exemplary embodiment of the catheter 100 has a negligible load value (e.g., less than 50 GF) between 0 and 10 cm from the distal end 105. The load value tends to increase between about 12 cm from the distal end 105 to about 25 cm from the distal end 105, and then tends to level off between about 25 cm from the distal end 105 to about 40 cm from the distal end 105. The rate and degree of load increase between the distance of 25 cm to 40 cm are different in different illustrated embodiments, wherein each illustrated embodiment has a different tapering rate, degree of tapering, and length of tapering at the distal end section 102C of the catheter 100.

[0116] Fig. 15B Focus on distance Fig.15A The critical range of the distal end 105 of the various exemplary embodiments shown in FIG. Fig. 15B As shown, depending on the characteristics of the tapering rate, degree of tapering, and length of tapering including the taper on the distal section 102C of the catheter 100, the load will typically increase from less than 100 GF to slightly less than 1000 GF and slightly greater than 1800 GF.

[0117] As previously discussed, the proximal segment 102A of an exemplary embodiment of the catheter 100 can have a first stiffness, the middle segment 102B can have a second stiffness less than or equal to the first stiffness, and the distal segment 102C can have a third stiffness less than or equal to the first stiffness; the second stiffness decreases from the first stiffness to the second stiffness along the length of the middle segment 102B.

[0118] like FIG. 15A to FIG. 15BAs shown, the first stiffness can be greater than 1000GF (e.g., between 1000GF and 1850GF), and the third stiffness can be less than 100GF (e.g., between 0GF and 100GF, for example, in some embodiments, less than 50GF). The length of the distal section 102C measured from the distal end 105 of the catheter 100 to the proximal end 104 of the catheter 100 can be less than 20cm. The length of the intermediate section 102B measured from the proximal end of the distal section 102C of the catheter 100 to the distal end of the proximal section 102A of the catheter 100 can be less than 25cm. However, it should be understood that such values ​​are only for exemplary and illustrative purposes and should not be interpreted as limiting the range.

[0119] Although the present invention has been described according to specific embodiments and applications, additional embodiments and modifications may be produced by those skilled in the art based on this teaching without departing from the spirit or scope of the invention claimed. Therefore, it should be understood that the drawings and descriptions herein are provided by way of example to facilitate understanding of the present invention and should not be interpreted as limiting the scope of the present invention.

Claims

1. An intravascular catheter, comprising: an elongated member having a proximal section, a middle section, and a distal section, the distal section of the elongated member having an enlarged portion having a larger diameter than the proximal section and the middle section; a conduit extending through the elongated member; as well as A first core wire is disposed within the elongated member adjacent the conduit, the distal end of the first core wire terminating prior to the enlarged portion of the elongated member.

2. An intravascular catheter according to claim 1, wherein the length of the distal segment of the slender member is between 7% and 16% of the length of the slender member, and wherein the first core wire does not extend into the distal segment.

3. The intravascular catheter according to claim 2, wherein: The length of the elongated member measured from the distal end of the elongated member to the proximal end of the elongated member is between 150 centimeters and 165 centimeters, and wherein the length of the distal section is between 15 centimeters and 20 centimeters. The intravascular catheter according to claim 1 , wherein the first core wire is fixed to an outer circumference of the tube.

5. An intravascular catheter according to claim 1, wherein the conduit is positioned below a longitudinal axis extending through the center of the slender member.

6. An intravascular catheter according to claim 5, wherein the first core wire is positioned above the longitudinal axis extending through the center of the slender member.

7. An intravascular catheter according to claim 1, wherein the proximal end of the first core wire extends beyond the proximal end of the slender member.

8. An intravascular catheter according to claim 1, wherein the distal end of the first core wire is at least partially coiled around the tube.

9. The intravascular catheter of claim 1, wherein the first core wire has a linear section and a coiled section, the linear section extending parallel to the tube and the coiled section winding around the tube.

10. The intravascular catheter of claim 9, wherein the coiled section of the first core wire is positioned within a middle section of the elongated member.

11. The intravascular catheter of claim 1, wherein at least a portion of the elongated member tapers from a larger diameter to a smaller diameter.

12. The intravascular catheter of claim 1, further comprising a second core wire within the elongated member adjacent to the conduit, wherein a length of the first core wire is different than a length of the second core wire.

13. An intravascular catheter according to claim 12, wherein the distal end of the second core wire terminates before the expanded portion of the slender member.

14. The intravascular catheter of claim 12, further comprising a third core wire within the elongated member adjacent to the conduit and a fourth core wire within the elongated member adjacent to the conduit.

15. The intravascular catheter of claim 14, wherein the first core wire, the second core wire, the third core wire, and the fourth core wire are each positioned radially around the conduit.

16. The intravascular catheter of 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 of claim 14, wherein the first core wire, the second core wire, the third core wire, and the fourth core wire each have a first section composed of stainless steel and a second section composed of nitinol.

18. The intravascular catheter of claim 1, wherein the proximal segment has a first stiffness, the middle segment has a second stiffness less than or equal to the first stiffness, and the distal segment has a third stiffness less than or equal to the first stiffness, and Wherein the second stiffness decreases from the first stiffness to the third stiffness along the length of the intermediate section.

19. The intravascular catheter of claim 18, wherein the first stiffness is at least 1000 grams-force (GF) and the third stiffness is less than 50 grams-force (GF).

20. The intravascular catheter of claim 19, wherein the length of the distal segment measured from the distal end of the elongated member to the proximal end of the elongated member is less than 20 centimeters.

21. The intravascular catheter of claim 20, wherein the length of the intermediate section measured from the proximal end of the distal section to the distal end of the proximal section is less than 25 centimeters.

22. An intravascular catheter, comprising: an elongated member having a proximal section, a middle section, and a distal section, the distal section of the elongated member having an enlarged portion having a larger diameter than the proximal section and the middle section; a conduit extending through the elongated member; as well as A stiffening member is disposed within the elongated member adjacent the conduit, wherein a distal end of the stiffening member terminates prior to the enlarged portion of the elongated member.

23. The intravascular catheter of claim 22, wherein the rigidifying member is comprised of a core wire, wherein the core wire comprises a linear section extending parallel to the conduit and a coiled section winding around the conduit.

24. The intravascular catheter of claim 22, wherein the rigidizing component is composed of a plurality of core wires, wherein each of the plurality of core wires has a different length.

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