Patent Application
20240009430
This invention relates to the field of guidewires for advancing intraluminal devices such as stent delivery catheters, balloon dilatation catheters, atherectomy catheters and the like within body lumens.
In a typical peripheral vessel procedure a guidewire is percutaneously introduced into a patient's peripheral artery, e.g., femoral artery, by means of a conventional Seldinger technique and advanced therein until the distal tip of the guidewire reaches a lesion or obstruction in the femoral artery. The peripheral artery will most commonly be a femoral artery, such as a superficial femoral artery or a common femoral artery, but could also be an iliac artery, a popliteal artery, a posterior tibial artery, a peroneal artery, an anterior tibial artery, and the like. For consistency, references below will typically be made to the femoral artery. The methods comprise a series of steps which are performed endovascularly in a femoral artery, typically the superficial femoral artery including the popliteal artery which is an extension of the superficial femoral artery, as well as in one or more adjacent femoral veins including a popliteal vein which is an extension of the femoral vein. The methods comprise forming a proximal penetration from the femoral artery to an adjacent femoral vein at a location above the occlusion. A guidewire is advanced down the femoral artery, through the proximal penetration, and into the femoral vein. Typically, the guidewire will be advanced contralaterally over the iliac arch from the opposite leg of the patient. There are two basic techniques for advancing a guidewire into the desired location within the patient's coronary anatomy, the first is a preload technique which is used primarily for over-the-wire (OTW) devices and the second is a bare wire technique which is used primarily for rapid exchange type systems. With the preload technique, a guidewire is positioned within an inner lumen of an OTW device such as a dilatation catheter or stent delivery catheter with the distal tip of the guidewire just proximal to the distal tip of the catheter and then both are advanced through the guiding catheter to the distal end thereof. The guidewire is first advanced out of the distal end of the guiding catheter into the patient's peripheral vasculature until the distal end of the guidewire crosses the location where the interventional procedure is to be performed, e.g., a lesion to be dilated or a dilated region where a stent is to be deployed. The catheter, which is slidably mounted onto the guidewire, is advanced out of the guiding catheter into the patient's vasculature over the previously introduced guidewire until the operative portion of the intravascular device, e.g., the balloon of a dilatation or a stent delivery catheter, is properly positioned across the arterial location. Once the catheter is in position with the operative means located within the desired vascular location, the interventional procedure is performed. The catheter can then be removed from the patient over the guidewire. Usually, the guidewire is left in place for a period of time after the procedure is completed to ensure reaccess to the arterial location.
With the bare wire technique, the guidewire is first advanced by itself through the guiding catheter until the distal tip of the guidewire extends beyond the arterial location where the procedure is to be performed. Then a rapid exchange (RX) catheter is mounted onto the proximal portion of the guidewire which extends out of the proximal end of the guiding catheter, which is outside of the patient. The catheter is advanced over the guidewire, while the position of the guidewire is fixed, until the operative means on the RX catheter is disposed within the vascular location where the procedure is to be performed. After the procedure, the intravascular device may be withdrawn from the patient over the guidewire or the guidewire advanced further within the vasculature for an additional procedure.
Conventional guidewires for angioplasty, stent delivery, atherectomy and other vascular procedures usually comprise an elongated core member with one or more tapered sections near the distal end thereof and a flexible body such as a helical coil or a tubular body of polymeric material disposed about the distal portion of the core member. A shapeable member, which may be the distal extremity of the core member or a separate shaping ribbon, which is secured to the distal extremity of the core member, extends through the flexible body and is secured to the distal end of the flexible body by soldering, brazing or welding which forms a rounded distal tip. Torqueing means are provided on the proximal end of the core member to rotate, and thereby steer, the guidewire while it is being advanced through a patient's vascular system.
What has been needed is a guidewire that has a proximal segment geometry that is receptive to use with a torque device so that the physician can more easily advance the guidewire through tortuous vasculature. The present invention satisfies these and other needs by providing enhanced torque response, improved tactile feel, increased pushability as the guidewire is advanced distally, and smoother tracking through the vasculature.
In one aspect of the invention, a guidewire is advanced into a patient with the assistance of a torque device. Since commercial torque devices have some difficulty with engagement of round cross-section guidewires, the present invention provides for a guidewire having round cross-section segments alternating with non-round cross-section segments.
A guidewire has an elongated core member having a proximal segment and a distal segment. The distal segment has a distal end which typically has a helical coil mounted thereon. As the guidewire is advanced distally into a patient's vasculature, for example into the femoral arteries, for the distal 50 cm of the guidewire there is no need for the physician to use a torque device on the guidewire because there would not be any significant tortuosity. This distance, L1 in
Again referring to
The non-round cross-section segment alternates along the proximal segment with round cross-section segments. The round cross-section segments have a distal end and a proximal end, and have a length L3 (
Since the round cross-section segments have more mass and a greater diameter than the non-round cross-section segment, they provide better torque transmission, while the non-round cross-section segments provide better surface contact with the torque device.
The non-round cross-section segments include a square cross-section segment, a triangle, a pentagon, an octagon, and a rectangle. In one embodiment, the square cross-section segments are aligned out-of-phase with each other so that as the guidewire tracks around curves, the flats on the square cross-section segments are at different contact points thereby enhancing the tracking of the guidewire.
Prior art guidewires typically include an elongated core wire having a flexible atraumatic distal end. A prior art guidewire 10 is shown in
The core member 11 may be formed of stainless steel, NiTi alloys or combinations thereof. The core member 11 is optionally coated with a lubricious coating such as a fluoropolymer, e.g., TEFLON® available from DuPont, which extends the length of the proximal core section. Hydrophilic coatings may also be employed. The length and diameter of prior art guidewire 10 may be varied to suit the particular procedures in which it is to be used and the materials from which it is constructed. The length of the guidewire 10 generally ranges from about 65 cm to about 320 cm, more typically ranging from about 160 cm to about 200 cm, and preferably from about 175 cm to about 190 cm or 300 cm for the peripheral anatomy. The guidewire diameter generally ranges from about 0.008 inch to about 0.035 inch (0.203 to 0.889 mm), more typically ranging from about 0.012 inch to about 0.018 inch (0.305 to 0.547 mm), and preferably about 0.014 inch (0.336 mm) for coronary anatomy and 0.018 inch (0.547 mm) and 0.035 inch (0.889 mm) for peripheral anatomy.
The flexible segment 16 terminates in a distal end 18. Flexible body member 14, preferably a coil, surrounds a portion of the distal section of the elongated core 13, with a distal end 19 of the flexible body member 14 secured to the distal end 18 of the flexible segment 16 by the body of solder 20. The proximal end 22 of the flexible body member 14 is similarly bonded or secured to the distal core section 13 by a body of solder 23. Materials and structures other than solder may be used to join the flexible body 14 to the distal core section 13, and the term “solder body” includes other materials such as braze, epoxy, polymer adhesives, including cyanoacrylates and the like.
The wire from which the flexible body 14 is made generally has a transverse diameter of about 0.001 to about 0.004 inch, preferably about 0.002 to about 0.003 inch (0.05 mm). Multiple turns of the distal portion of the coil may be expanded to provide additional flexibility. The coil may have a diameter or transverse dimension that is about the same as the proximal core section 12. The flexible body member 14 may have a length of about 2 to about 40 cm or more, preferably about 2 to about 10 cm in length. A flexible body member 14 in the form of a coil may be formed of a suitable radiopaque material such as platinum or alloys thereof or formed of other material such as stainless steel and coated with a radiopaque material such as gold.
The flexible segment 16 has a length typically ranging about 1 to about 12 cm, preferably about 2 to about 10 cm, although longer segments may be used. The form of taper of the flexible segment 16 provides a controlled longitudinal variation and transition in flexibility (or degree of stiffness) of the core segment. The flexible segment is contiguous with the core member 11 and is distally disposed on the distal section 13 so as to serve as a shapable member.
In
Typically, the first tapered core segment is about 3 cm in length and the second tapered core segment is about 4 cm in length. The guidewire 10 has a proximal segment of about 0.014 inch (0.36 mm) in diameter, the first tapered core segment has a diameter ranging from 0.014 inch down to about 0.008 inch (0.36-0.20 mm) and the second tapered core segment has a diameter ranging from about 0.008 inch to about 0.002 inch (0.20-0.05 mm). A body of solder 21 secures the proximal end of the helical coil 14 to an intermediate location on the second tapered core segment 28.
The core member 12 is coated with a lubricious coating 29 such as a fluoropolymer, e.g., TEFLON® available from DuPont, which extends the length of the proximal segment 34. The distal portion is also provided a lubricous coating, not shown for purposes of clarity, such as a MICROGLIDE™ coating used by the present assignee, Abbott Cardiovascular Systems, Inc., on many of its commercially available guidewires. A hydrophilic coating may also be employed.
The core member 12 may be formed of stainless steel, CoCr, Ti, and NiTi alloys or combinations thereof or other high strength alloys as is well known in the art.
The helical coil 14 is formed of a suitable radiopaque material such as platinum or alloys thereof or formed of other material such as stainless steel and coated with a radiopaque material such as gold. The wire from which the coil is made generally has a transverse diameter of about 0.003 inch (0.05 mm). The overall length of the helical coil 14 is typically about 3 cm. Multiple turns of the distal portion of coil 14 may be expanded to provide additional flexibility.
One of the problems associated with prior art guidewires such as shown in
In keeping with the invention and as shown in
Again referring to
The non-round cross-section segment 50 alternates along the proximal segment 34 with round cross-section segments 62. The round cross-section segments 62 have a distal end 64 and a proximal end 66, and have a length L3 in the range from 5.0 cm to 10.0 cm. The length L3 coincides with the typical guidewire 30 distal advancement increments into the patient's vasculature. As can be seen in
Since the round cross-section segments 62 have more mass and a greater diameter than the non-round cross-section segment 50, they provide better torque transmission, while the non-round cross-section segments 50 provide better surface contact with the torque device 58.
The non-round cross-section segments 50 are shown in
In one embodiment, the guidewire 30 is formed from one continuous core wire that includes the round cross-section segments 62 and the non-round cross-section segments 50. The non-round cross-section segments 50 can be formed by multiple different processes such as grinding, laser cutting, or chemical removal, all of which is known in the art.
In one embodiment, there are rounded edges 68 and 70 where the round cross-section segments 62 abut the non-round cross-section segments 50. The rounded edges provide a smooth transition and improve guidewire 30 tracking.
Although this invention has been disclosed in the context of certain embodiments and examples, it will be understood by those skilled in the art that the invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. In addition, while several variations of the embodiments of the invention have been shown and described in detail, other modifications, which are within the scope of this invention, will be readily apparent to those having ordinary of skill in the art based upon this disclosure. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the invention. It should be understood that various features and aspects of the disclosed embodiments can be combined with, or substituted for, one another in order to form varying modes of the embodiments of the disclosed invention. Thus, it is intended that the scope of the invention herein disclosed should not be limited by the particular embodiments described above.
