Guide wire core having a non-circular cross section

Abstract

An elongate guidewire for use in angioplasty and related procedures. The guidewire includes a proximal section and a distal section. The proximal section has a plurality of circular cross-section segments and a plurality of non-circular cross-section segments alternating therebetween. The non-circular cross-section segments can include a square, a rectangle, a pentagon, a triangle, an octagon, and a polygon.

Description

Technical Field

[0001] The present invention relates to the field of guidewires for advancing intraluminal devices such as stent delivery catheters, balloon dilation catheters, and atelectomy catheters within a body cavity.

Background Art

[0002] In a typical peripheral vascular procedure, a guidewire is percutaneously introduced into a patient's peripheral artery (e.g., the femoral artery) by the conventional Seldinger technique and advanced through it until the distal tip of the guidewire reaches the lesion or occlusion in the femoral artery. The peripheral artery is most commonly the femoral artery such as the superficial femoral artery or the common femoral artery, but may also be the iliac artery, popliteal artery, posterior tibial artery, peroneal artery, anterior tibial artery, etc. For the sake of uniformity, hereinafter, typically, the femoral artery will be described. The method includes a series of steps performed intravascularly in one or more adjacent femoral veins including the femoral artery (typically the superficial femoral artery including the popliteal artery which is an extension of the superficial femoral artery) and the popliteal vein which is an extension of the femoral vein. The method includes the step of forming a proximal perforation from the femoral artery to the adjacent femoral vein at a position above the occlusion. The guidewire is advanced down the femoral artery, through the proximal perforation, and into the femoral vein. Typically, the guidewire is advanced across the iliac arch from the opposite leg of the patient to the contralateral side. There are two basic techniques for advancing the guidewire to a desired position within the anatomical structure of the patient's coronary artery. The first technique is the preload technique mainly used for over-the-wire (OTW) devices, and the second technique is the bare wire technique mainly used for rapid exchange type systems. In the preload technique, the guidewire is positioned within the inner lumen of an OTW device such as an inflation catheter or a stent delivery catheter with the distal tip of the guidewire being immediately proximal to the distal tip of the catheter, and then both are advanced through the guiding catheter to its distal end. The guidewire is first advanced out of the distal end of the guiding catheter and into the patient's peripheral vascular system until the distal end of the guidewire crosses the location where the interventional procedure is to be performed (e.g., the lesion to be dilated or the dilation area where the stent is to be deployed). A catheter slidably mounted on the guidewire is advanced out of the guiding catheter and into the patient's vascular system on the previously introduced guidewire until the operating portion of the intravascular device (e.g., the balloon of the inflation catheter or the stent delivery catheter) is properly positioned across the arterial location.When the catheter is placed at a predetermined position together with the operating means located within the desired vascular position, an interventional procedure is performed. Then, the catheter can be removed from the patient along the guide wire. Usually, the guide wire is left in place for a certain period after the procedure to ensure re-access to the arterial position.

[0003] In bare wire technology, the guide wire is first advanced alone through the guiding catheter until the distal tip of the guide wire extends beyond the arterial position where the procedure is to be performed. Then, a rapid exchange (RX) catheter is attached onto the proximal portion of the guide wire that extends outside the proximal end of the guiding catheter located outside the patient. The catheter is advanced along the guide wire until the operating means on the RX catheter is placed within the vascular position where the procedure is to be performed while keeping the position of the guide wire fixed. After the procedure, the intravascular device can be withdrawn from the patient along the guide wire, or the guide wire can be further advanced within the vascular system for additional procedures.

[0004] Conventional guide wires for angioplasty, stent delivery, atherectomy, and other vascular procedures typically comprise an elongated core member having one or more tapered sections near its distal end, and a flexible body such as a helical coil or tubular body of polymeric material disposed around the distal portion of the core member. A formable member, which can be the distal end of the core member, or a separate forming ribbon fixed to the distal end of the core member, extends through the flexible body and is fixed to the distal end of the flexible body by soldering, brazing, or welding to form a rounded distal tip. Torque applying means are provided at the proximal end of the core member to rotate and direct the guide wire while it is being advanced through the patient's vascular system.

[0005] What is needed is a guidewire having a geometry of a proximal segment that can be used with a torque device so that a physician can more easily advance it through a tortuous vasculature. The present invention meets these and other needs by improving torque response, improving tactile sensation, enhancing pushability as the guidewire advances distally, and following the vasculature more smoothly. SUMMARY OF THE INVENTION

[0006] In one aspect of the invention, the guidewire is advanced into a patient's body with the aid of a torque device. Since commercially available torque devices have some problems engaging a guidewire with a circular cross-section, the present invention provides a guidewire having a circular cross-section segment and a non-circular cross-section segment.

[0007] The guidewire has an elongate core member having a proximal segment and a distal segment. The distal segment typically has a distal end to which a helical coil is attached. When the guidewire is advanced distally into a patient's vasculature, e.g., into the femoral artery, there is no significant tortuosity for the distal 50 cm of the guidewire, so a physician does not need to use a torque device on the guidewire. This distance L1 in FIG. 4 (e.g., contralateral access of the superficial femoral artery) means the length of the guidewire that can be inserted into the patient without the need for tactile enhancement or torque device engagement. The length L1 is typically about 50 cm, but can vary in the range of 36 cm to 72 cm depending on a number of factors including the height from the patient.

[0008] Referring again to FIG. 4, the length L2 along the proximal segment is the portion of the guidewire that is outside the patient, and since the length L1 is advancing distally into the more tortuous vasculature, it shows the portion of the guidewire that requires tactile enhancement and torque device engagement. In one embodiment, the non-circular cross-section segment has a distal end and a proximal end. The distal end abuts the proximal end of the distal segment of L1. The non-circular cross-section segment preferably has a length of at least 2.0 mm and at most 30 mm. In one embodiment, the non-circular cross-section segment has a length in the range of 2.0 mm to 5.0 mm. In another embodiment, the non-circular cross-section segment has a length in the range of 1.0 cm to 2.0 cm. The length of the non-circular cross-section segment must be a length corresponding to the length of the operable portion of the torque device. One such torque device is commercially available and is sold by Abbott Vascular Systems (Santa Clara, California). The torque device has a plurality of collets (finger-like structures) that can open and close to engage the non-circular cross-section segment. Thus, the length of the non-circular cross-section segment must be long enough to accommodate and engage the collets of the torque device. The torque device, when attached to the non-circular cross-section segment, can be used to apply torque to the guidewire and further advance the guidewire distally into the patient's body by a length of 5.0 cm to 10.0 cm.

[0009] The non-circular cross-section segments are arranged alternately with the circular cross-section segments along the proximal segment. The circular cross-section segments have a distal end and a proximal end and have a length L3 (Figure 4) in the range of 5.0 cm to 10.0 cm. The length L3 corresponds to a typical distal advancement increment of the guide wire into the patient's vasculature. The non-circular cross-section segments are arranged alternately with the circular cross-section segments along the proximal segment of the guide wire. There is no stipulation regarding the number of non-circular cross-section segments required, but there must be a sufficient number such that the physician can use the torque device several times to advance the distal end of the distal segment into the position within the patient's coronary artery. For example, if the guide wire is 300 cm in length, the distal end of the distal segment will surely be positioned at the appropriate location in the patient's coronary artery, so there is no need to have non-circular cross-section segments in the proximal 100 cm of the guide wire. On the other hand, if the guide wire is 190 cm in length, the non-circular cross-section segments need to be positioned along the entire length of the proximal segment.

[0010] The circular cross-section segments have a greater mass and diameter than the non-circular cross-section segments, thus providing better torque transmission, while the non-circular cross-section segments provide better surface contact with the torque device.

[0011] The non-circular cross-section segments include square, triangular, pentagonal, octagonal, and rectangular cross-section segments. In one embodiment, the square cross-section segments are phase-shifted and aligned with each other such that when the guide wire follows a curve, the planes on the square cross-section segments are at different contact points, thereby improving the followability of the guide wire.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0013] Conventional guide wire Conventional guidewires typically include an elongated core wire having a flexible atraumatic distal end. A conventional guidewire 10 is shown in FIGS. 1 - 3 and includes an elongated core member 11 having a proximal core section 12, a distal core section 13, and a flexible body member 14 fixed to the distal core section. The distal core section 13 has a tapered segment 15, a flexible segment 16 adjacent to the tapered segment 15 in the distal direction, a distal end 13a, and a proximal end 13b. The distal section 13 may further have two or more tapered segments 15 having a typical distal - tapering taper with a substantially circular cross - section. The proximal core section 12 typically has a circular cross - section. The longitudinal axis 17 extends over the entire length of the conventional guidewire 10.

[0014] The core member 11 can be formed from stainless steel, a NiTi alloy, or a combination thereof. The core member 11 is optionally coated with a lubricious coating such as a fluoropolymer (e.g., TEFLON® available from Dupont) that extends over the length of the proximal core section. A hydrophilic coating may also be used. The length and diameter of the conventional guidewire 10 can be varied to suit the particular procedure and constituent materials used. The length of the guidewire 10 generally ranges from about 65 cm to about 320 cm, more typically ranges from about 160 cm to 200 cm, and preferably ranges from about 175 cm to about 190 cm or 300 cm (for the anatomical structure of peripheral arteries). The diameter of the guidewire generally ranges from about 0.008 inches to about 0.035 inches (0.203 mm to 0.889 mm), more typically ranges from about 0.012 inches to about 0.018 inches (0.305 mm to 0.547 mm), and preferably is about 0.014 inches (0.336 mm) for the anatomical structure of coronary arteries and 0.018 inches (0.547 mm) and 0.035 inches (0.889 mm) for the anatomical structure of peripheral arteries.

[0015] The flexible segment 16 terminates at the distal end 18. The flexible member 14 (preferably a coil) surrounds a portion of the distal section of the elongated core 13, and the distal end 19 of the flexible member 14 is fixed to the distal end 18 of the flexible segment 16 by the solder body 20. The proximal end 22 of the flexible member 14 is similarly adhered or fixed to the distal core section 13 by the solder body 23. Materials and structures other than solder can be used to join the flexible body 14 to the distal core section 13, and the term "solder body" includes other materials (e.g., polymeric adhesives including brazing materials, epoxies, cyanoacrylates, etc.).

[0016] The wire forming the flexible body 14 generally has a transverse diameter of from about 0.001 inches to about 0.004 inches (0.025 mm to 0.1 mm), preferably from about 0.002 inches to about 0.003 inches (0.05 mm). The distal portion of the multiple windings of the coil can be splayed to provide additional flexibility. The coil can have approximately the same diameter or transverse dimension as the proximal core section 12. The flexible member 14 can have a length of from about 2 cm to about 40 cm or more, preferably from about 2 cm to about 10 cm. The flexible member 14 in the form of a coil can be formed from a suitable radiopaque material such as platinum or an alloy thereof, or can be formed from other materials such as stainless steel and coated with a radiopaque material such as gold.

[0017] The flexible segment 16 typically has a length in the range of from about 1 cm to about 12 cm, preferably from about 2 cm to about 10 cm, although longer segments may be used. The tapered form of the flexible segment 16 regulates the longitudinal change and transition in the flexibility (or degree of rigidity) of the core segment. The flexible segment is adjacent to the core member 11 and is disposed distally on the distal section 13 so as to function as a formable member.

[0018] In FIGS. 2-3, the prior art guidewire 10 has a core member 32, a helical coil 14, a first tapered core segment 26, and a second tapered core segment 28 that is distally adjacent to the first tapered core segment. The second tapered core segment 28 is more tapered than the first tapered core segment, and this additional taper provides a much smoother transition as the distal portion of the guidewire 10 advances through the tortuous passageway. The taper of the first tapered core segment 26, i.e., the angle between the longitudinal axis 17 and the tangent of the first tapered core segment 26, is typically about 0.146°, and the taper of the second tapered core segment 28, i.e., the angle between the longitudinal axis 17 and the second tapered core segment 28, is greater than the first angle and is typically about 0.109° as shown in the illustration of the guidewire 10 in FIG. 2. Further, not all of the plurality of tapered core segments need to be tapered more distally. However, two or more adjacent tapered core segments over a length of about 5 cm to 15 cm need to have an increasing taper distally.

[0019] Typically, the length of the first tapered core segment is about 3 cm and the length of the second tapered core segment is about 4 cm. The guidewire 10 has a proximal segment with a diameter of about 0.014 inches (0.36 mm), the first tapered core segment has a diameter in the range of 0.014 inches to about 0.008 inches (0.36 mm to 0.20 mm), and the second tapered core segment has a diameter in the range of about 0.008 inches to about 0.002 inches (0.20 mm to 0.05 mm). The solder body 21 secures the proximal end of the helical coil 14 to an intermediate position on the second tapered core segment 28.

[0020] The core member 12 is coated with a lubricious coating 29 such as a fluoropolymer (e.g., TEFLON® available from Dupont) that extends over the length of the proximal segment 34. Further, at the distal portion, a lubricious coating (not shown for clarity) such as the MICROGLID™ coating used by the assignee Abbott Cardiovascular Systems in many commercially available guidewires is applied. A hydrophilic coating may also be used.

[0021] The core member 12 can be formed from stainless steel, CoCr, Ti, NiTi alloy, or combinations thereof, or other high-strength alloys well-known in the art.

[0022] The helical coil 14 is formed from a suitable radiopaque material such as platinum or its alloy, or other materials such as stainless steel, and is coated with a radiopaque material such as gold. The wire forming the coil generally has a cross diameter of about 0.003 inches (0.05 mm). The overall length of the helical coil 14 is typically about 3 cm. The distal portion of the multiple turns of the coil 14 can be splayed to provide additional flexibility.

[0023] One of the problems associated with prior art guidewires as shown in FIGS. 1 - 3 is that the guidewire has a circular cross-section, and as a result, it is difficult for a physician to grip the guidewire and apply torque to the guidewire to advance it through a tortuous vascular system.

[0024] Guidewire Core with Non-Circular Cross-Section According to the present invention, as shown in FIGS. 4-10, the guide wire 30 has an elongated core member 32 having a proximal segment 34 and a distal segment 36. The distal segment 36 typically has a distal end 37 to which a helical coil 38 is attached. When the guide wire 30 is advanced distally into a patient's vasculature, for example, into the brachial artery, there is no significant tortuosity for the distal 50 cm of the guide wire 30, so that the physician does not need to use a torque device on the guide wire. This distance L1 in FIG. 4 means the length of the guide wire 30 that is inserted into the patient without the need for tactile enhancement or torque device engagement. The length L1 is typically about 50 cm, but can vary in the range of 36 cm to 72 cm depending on a number of factors including the patient's height.

[0025] Referring again to FIG. 4, the length L2 along the proximal segment 34 is the portion of the guide wire 30 that is outside the patient and shows the portion of the guide wire 30 that requires tactile enhancement and torque device engagement as the length L1 advances distally into a more tortuous vasculature. In one embodiment, as shown in FIGS. 4-10, the non-circular cross-section segment 50 has a distal end 52 and a proximal end 54. The distal end 52 abuts the proximal end 56 of the distal segment 36 of L1. The non-circular cross-section segment 50 preferably has a length of at least 2.0 mm and at most 30 mm. In one embodiment, the non-circular cross-section segment 50 has a length in the range of 2.0 mm to 5.0 mm. In another embodiment, the non-circular cross-section segment 50 has a length in the range of 1.0 cm to 2.0 cm. The length of the non-circular cross-section segment 50 must be a length corresponding to the length of the operable portion of the torque device 58. One torque device 58 shown in FIG. 11 is commercially available and has a plurality of collets 60 (finger-like structures) that can open and close to engage the non-circular cross-section segment 50. Thus, the length of the non-circular cross-section segment 50 must be long enough to accommodate the collets 60 of the torque device 58 and engage the collets. One torque device 58 is attached to the non-circular cross-section segment 50 and can be used to apply torque to the guide wire 30 and advance the guide wire further distally into the patient's body by a length of 5.0 cm to 10.0 cm.

[0026] The non-circular cross-section segment 50 is alternately arranged with the circular cross-section segment 62 along the proximal segment 34. The circular cross-section segment 62 has a distal end 64 and a proximal end 66 and has a length L3 in the range of 5.0 cm to 10.0 cm. The length L3 corresponds to the distal advancement increment of a typical guide wire 30 into the patient's vasculature. As shown in FIGS. 4 to 10, the non-circular cross-section segment 50 is alternately arranged with the circular cross-section segment 62 along the proximal segment 34 of the guide wire 30. There is no stipulation regarding the required number of non-circular cross-section segments 50, but it is necessary to be a sufficient number for the physician to be able to use the torque device several times to advance the distal end 37 of the distal segment 36 to a position within the patient's coronary artery. For example, when the guide wire 30 is 300 cm in length, the distal end 37 of the distal segment 36 will surely be positioned at an appropriate position in the patient's coronary artery, so there is no need to have the non-circular cross-section segment 50 in the proximal 100 cm of the guide wire 30. On the other hand, when the guide wire 30 is 190 cm in length, the non-circular cross-section segments need to be positioned along the entire length of the proximal segment 34.

[0027] The circular cross-section segment 62 has a greater mass and a larger diameter than the non-circular cross-section segment 50, thus providing better torque transmission, while the non-circular cross-section segment 50 provides better surface contact with the torque device 58.

[0028] The non-circular cross-section segment 50 is shown in FIGS. 5, 7, 9, and 12-15. FIGS. 5, 7, and 9 show square cross-section segments, FIG. 12 shows a triangular, FIG. 13 shows a pentagonal, FIG. 14 shows an octagonal, and FIG. 15 shows a rectangular cross-section segment. In one embodiment, as shown in FIGS. 5, 7, and 9, the square cross-section segments 50 are offset in phase and aligned with each other such that when the guide wire 30 follows a curve, the planes on the square cross-section segments 50 are at different contact points, thereby improving the followability of the guide wire 30. The other non-circular cross-section segments 50 shown in FIGS. 12-15 are also offset in phase and aligned to obtain the same result. In another embodiment, the non-circular cross-section segments 50 are aligned in the same phase.

[0029] In one embodiment, the guide wire 30 is formed from one continuous core wire including a circular cross-section segment 62 and a non-circular cross-section segment 50. The non-circular cross-section segment 50 can be formed by a plurality of different processes such as grinding, laser cutting, or chemical removal, all of which are well known in the art.

[0030] In one embodiment, there are rounded edges 68, 70 where the circular cross-section segment 62 abuts the non-circular cross-section segment 50. The rounded edges form a smooth transition and improve the followability of the guide wire 30.

[0031] Although the present invention is disclosed in the context of specific embodiments and examples, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and / or uses of the present invention, as well as obvious modifications and equivalents thereof. Further, although some variations of embodiments of the present invention have been shown and described in detail, other modifications within the scope of the present invention will be readily apparent to those skilled in the art based on this disclosure. Various combinations or partial combinations of specific features and aspects of the embodiments may be made, and these are also intended to be included within the scope of the present invention. It should be understood that the various features and aspects of the disclosed embodiments are combinable with each other or alternative to each other to form various forms of the disclosed embodiments of the invention. Accordingly, it is intended that the scope of the present invention disclosed herein should not be limited by the specific embodiments described above.

Claims

**Claim 1** A guide wire comprising an elongated core member having a proximal segment and a distal segment, wherein the distal segment has a circular cross-sectional segment, and the proximal segment alternately has a plurality of circular cross-sectional segments and a plurality of non-circular cross-sectional segments, the guide wire. **Claim 2** The guide wire according to claim 1, wherein the plurality of non-circular cross-sectional segments are selected from the group consisting of a square, a rectangle, a pentagon, a triangle, an octagon, and a polygon. **Claim 3** The guide wire according to claim 2, wherein each of the plurality of non-circular cross-sectional segments has a length in the range of 2.0 mm to 30.0 mm. **Claim 4** The guide wire according to claim 1, wherein each of the plurality of non-circular cross-sectional segments has a length in the range of 2.0 mm to 5.0 mm. **Claim 5** The guide wire according to claim 1, wherein each of the plurality of circular cross-sectional segments in the proximal segment has a length in the range of 5.0 cm to 10.0 cm. **Claim 6** The guide wire according to claim 1, wherein each of the plurality of non-circular cross-sectional segments has a square cross-sectional shape. **Claim 7** The guide wire according to claim 1, wherein at least one of the plurality of non-circular cross-sectional segments is a square cross-sectional segment. **Claim 8** The guide wire according to claim 1, wherein the plurality of non-circular cross-sectional segments are misaligned and aligned. **Claim 9** A guide wire comprising an elongated core member having a proximal segment and a distal segment, wherein the distal segment has a circular cross-sectional segment, and the proximal segment alternately has at least one circular cross-sectional segment and at least one non-circular cross-sectional segment, the guide wire. **Claim 10** The guide wire according to claim 9, wherein the at least one non-circular cross-sectional segment is selected from the group consisting of a square, a rectangle, a pentagon, a triangle, an octagon, and a polygon. **Claim 11** The guide wire according to claim 10, wherein the at least one non-circular cross-sectional segment has a length in the range of 2.0 mm to 30.0 mm. **Claim 12** The guide wire according to claim 10, wherein the at least one non-circular cross-sectional segment has a length in the range of 2.0 mm to 5.0 mm. **Claim 13** The guide wire according to claim 9, wherein the at least one circular cross-sectional segment in the proximal segment has a length in the range of 5.0 cm to 10.0 cm. **Claim 14** The guide wire according to claim 9, wherein the at least one non-circular cross-sectional segment has a square cross-sectional shape.

15. A guide wire comprising an elongated core member having a proximal segment and a distal segment, wherein the distal segment has a circular cross-sectional segment, the proximal segment having a plurality of circular cross-sectional segments and a plurality of square cross-sectional segments alternately. Guide wire.

16. The guide wire according to claim 15, wherein each of the plurality of square cross-sectional segments has a length in the range of 2.0 mm to 30.0 mm.

17. The guide wire according to claim 15, wherein each of the plurality of square cross-sectional segments has a length in the range of 2.0 mm to 5.0 mm.

18. The guide wire according to claim 15, wherein each of the plurality of circular cross-sectional segments in the proximal segment has a length in the range of 5.0 cm to 10.0 cm.

19. The guide wire according to claim 15, wherein the plurality of square cross-sectional segments are misaligned and aligned.

20. The guide wire according to claim 15, wherein the plurality of square cross-sectional segments are aligned in the same phase.

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