Surgery – Diagnostic testing – Flexible catheter guide
Reexamination Certificate
2000-03-03
2001-10-02
Nasser, Robert L. (Department: 3736)
Surgery
Diagnostic testing
Flexible catheter guide
C604S523000
Reexamination Certificate
active
06296616
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to the field of guidewires for advancing intravascular devices such as stent delivery catheters, balloon dilatation catheters and atherectomy catheters within a body lumen
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 shapable 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. Torquing 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.
Further details of guidewires, and devices associated therewith for various interventional procedures can be found in U.S. Pat. No. 4,748,986 (Morrison et al.); U.S. Pat. No.4,538,622 (Samson et al.): U.S. Pat. No. 5,135,503 (Abrams); U.S. Pat. No. 5,341,818 (Abrams et al.); and U.S. Pat. No. 5,345,945 (Hodgson, et al.) which are hereby incorporated herein in their entirety by reference thereto.
In a typical coronary procedure using a guidewire, a guiding catheter having a preformed distal tip is percutaneously introduced into a patient's peripheral artery, e.g. femoral or brachial artery, by means of a conventional Seldinger technique and advanced and steered therein until the distal tip of the guiding catheter is seated in the ostium of a desired coronary artery.
There are two basic techniques for advancing a guidewire into the desired location within the patient's coronary anatomy through the in place guiding catheter. The first is a preload technique which is used primarily for over-the-wire (OTW) devices and the second is the bare wire technique which is used primarily for rail 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 coronary vasculature until the distal end of the guidewire crosses the arterial 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 coronary anatomy 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 arterial 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 is it is necessary. For example, in the event of arterial blockage due to dissected lining collapse, a rapid exchange type perfusion balloon catheter such as described and claimed in U.S. Pat. No. 5,516,336 (McInnes et al), can be advanced over the in-place guidewire so that the balloon can be inflated to open up the arterial passageway and allow blood to perfuse through the distal section of the catheter to a distal location until the dissection is reattached to the arterial wall by natural healing.
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 rail type catheter, such as described in U.S. Pat. No. 5,061,395 (Yock) and the previously discussed McInnes et al. which are incorporated herein by reference, 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 catheter, while the position of the guidewire is fixed, until the operative means on the rail type catheter is disposed within the arterial 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 coronary anatomy for an additional procedure.
SUMMARY OF THE INVENTION
The present invention is directed to an improved guidewire having a flexible distal section which facilitates advancement through a patient's body lumen.
The guidewire of the present invention has an elongated core member with proximal and distal core sections with a flexible tubular member such as a helical coil is disposed about and secured to the distal part of the distal core section. The distal core section has one or more distally tapering segments. Proximal to the flexible tubular member, the guidewire has an exterior surface which is shaped to provide a plurality of contact regions and non-contact regions between adjacent contact regions.
In one presently preferred embodiment, the intermediate portion is defined by a sheath disposed about the core member and preferably formed of a polymeric material. The contact region or regions of the intermediate portion of the guidewire is generally about 20 to about 60% of the surface of the sheath. The outer diameter of the contact regions of the intermediate portion is preferably the same or approximately the same as the outer diameter of the flexible tubular member or coil on the distal part of the distal shaft section. However, if the flexible tubular member is of different outer diameter than the proximal core section, the intermediate portion may taper from the outer diameter of the proximal core section to the outer diameter of the coil. The distances between the peaks of the contact regions should be about 0.05 to about 5.0 mm, preferably about 0.1 to about 0.5 mm. The depth of the recessed non-contact regions may be about 0.01 to about 0.1 mm, preferably about 0.025 to about 0.075 mm as measured from the peaks of the contact regions. While the presently preferred intermediate portion of the guidewire having the contact and non-contact regions extends distally from the flexible tubular member and terminates distal to the proximal core section, the section having the contact and non-contact regions can extend proximally over most or all of the proximal core section.
By reducing the area of surface contact between the guidewire and a body lumen or a catheter lumen in which the guidewire is being moved relative thereto, the resistance to movement is greatly reduced. In one embodiment of the invention, solid or liquid lubricant can be maintained within recessed non-contact regions to further reduce frictional drag on the guidewire as it moves through a lumen or the frictional drag on a catheter as the catheter is moved over the intermediate portion of the guidewire. Pharmaceutical materials and diagnostic and therapeutic agents may also be incorporated into the recessed non-contact regions.
In one presently preferred embodiment of the invention, the intermediate guidewire portion having the contact and non-contact regions is defined by an intermediate sheath disposed about at least part of the distal guidewire section proximal to the flexible tubular member or coil on the distal part of the distal section.
These and other advantages of the invention will become more apparent from the following detailed des
Advanced Cardiovascular Systems Inc.
Heller Ehrman White & McAuliffe
Nasser Robert L.
Wingood Pamela L
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