Surgery – Diagnostic testing – Flexible catheter guide
Reexamination Certificate
1998-09-30
2001-04-17
O'Connor, Cary (Department: 3736)
Surgery
Diagnostic testing
Flexible catheter guide
C604S164030, C604S523000, C604S286000
Reexamination Certificate
active
06217527
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to medical devices, kits, and methods used in the treatment of vascular occlusions. More particularly, the invention relates to systems and procedures for crossing chronic occlusions in blood vessels with guidewires that may facilitate performance of subsequent treatment and therapies including angioplasty, atherectomy and stenting procedures.
BACKGROUND OF THE INVENTION
Cardiovascular disease is a leading cause of mortality worldwide that can take on many different forms. A particularly troublesome form of cardiovascular disease results when a blood vessel becomes totally occluded with atheroma or plaque, referred to as a chronic total occlusion. Until recently, chronic total occlusions have usually been treated by performing a bypass procedure where an autologous or synthetic blood vessel is anastomotically attached to locations on the blood vessel upstream and downstream of the occlusion. While highly effective, such bypass procedures are quite traumatic to the patient. Recently, catheter-based intravascular procedures have been utilized to treat chronic total occlusions with increasing success. Catheter-based intravascular procedures include angioplasty, atherectomy, stenting, and the like, and are often preferred because they are much less traumatic to the patient. Before such catheter-based treatments can be performed, however, it is usually necessary to cross the occlusion with a guidewire to provide access for the interventional catheter. In some instances, crossing the occlusion with a guidewire can be accomplished simply by pushing the guidewire through the occlusion. The guidewire remains in the blood vessel lumen and provides the desired access path. In many cases, however, the guidewire inadvertently penetrates into the subintimal space between the intimal layer and the adventitial layer of the blood vessel as it attempts to cross the occlusion. Once in the subintimal space, it is very difficult and impossible in many instances to direct the guidewire back into the blood vessel lumen. In such cases, it will usually be impossible to perform the catheter-based intervention and other procedures may have to be employed that are relatively more traumatic. Catheters and methods for forming lateral penetrations through tissue to and from blood vessels past total occlusions are described in U.S. Pat. Nos. 5,443,497; 5,429,144; 5,409,019; 5,287,861; WO 97/13463; and WO 97/13471. Catheters having side guidewire entry ports spaced proximally from their distal tips are also described in U.S. Pat. Nos. 5,464,395; 5,413,581; 5,190,528; 5,183,470; 4,947,864; and 4,405,314. These and a variety of other specific interventional and pharmaceutical treatments have been devised over the years with varying levels of success for different applications.
SUMMARY OF THE INVENTION
The present invention provides methods and apparatus for crossing substantial or total occlusions in blood vessels. It is an object of the invention to traverse vascular occlusions or other blockages formed within blood vessels in order to provide pathways for the placement of guidewires or other interventional devices as part of an overall effort to restore or provide adequate circulation. It is advantageous to cross a substantially occluded blood vessel by finding and/or creating a path with the least or relatively low resistance through or around at least a portion of the occlusion which may include travel along or between the layers of a blood vessel wall in regions such as the subintimal space. The invention further provides methods, kits, and apparatus which facilitate crossing a chronic total occlusion in a blood vessel with a guidewire. In particular, catheters, guides, or other apparatus provided herein may be used with conventional or specialized guidewires to direct or redirect the guidewires from a subintimal space, or other areas between the different layers of a blood vessel wall, back into the blood vessel lumen. The disclosed apparatus include devices formed with relatively simple construction, and may be used in a relatively straight-forward manner.
One aspect of the invention provides apparatus for crossing a vascular occlusion by directing a lead device such as a guidewire around at a least a portion of the obstruction within the blood vessel wall. A deflecting catheter may controllably deflect or direct the guidewire through or around a vascular occlusion formed within the natural lumen of the vessel, and may direct the guidewire within a region in between the various layers of the vessel wall to completely or partially circumvent the blockage. The deflecting catheter may provide any combination of these controllable movements to position the guidewire in a manner that can facilitate interventional treatments such as stenting. Another variation of the invention includes a guidewire deflection system comprising a catheter body formed with at least one lumen extending along its length, a nosecone formed at the distal end of the catheter body having a distal and a lateral opening. The region surrounding the lateral opening may include an adjacent inclined surface. The distal opening and the lateral opening are both in communication with the catheter body lumen. In addition, a cannula may be included having a cannula port in communication with at least one passageway extending through at least a distal portion of the cannula. The distal end of the cannula may be configured to communicate with the inclined surface adjacent to the lateral opening to deflect the cannula away from the longitudinal axis of the catheter body. The distal portion of the cannula may further have a pre-formed shape resilient curve, and may be slidably positioned within the lumen of the catheter body. The distal portion may have a relatively axially aligned configuration with the lumen when the cannula is positioned within the catheter body, and a relatively curved configuration with the lumen when the cannula travels along the inclined surface and through the lateral opening of the catheter body when the cannula is distally advanced through the lumen within the catheter body. The guidewire deflection system may further comprise a guidewire configured to pass through the passageway of the cannula. A variety of imaging components or markers may be also positioned on various portions of the wire, cannula or catheter body. A hub assembly rotationally secured to the proximal end of the catheter body may be selected to controllably rotate the cannula and the catheter body.
In yet another embodiment of the invention, an intravascular catheter is provided having a catheter shaft formed with at least one longitudinal lumen. A nosecone may be positioned at the distal end of the catheter shaft having a first port in communication with the longitudinal lumen formed with a first cross-sectional area, and a second port in communication with the longitudinal lumen formed with a second cross-sectional area, wherein the first cross-sectional area is relatively larger that the second cross-sectional area. A cannula may be slidably positioned within at least a portion of the longitudinal lumen of the catheter shaft, and may be configured for passage through the first port which is relatively larger, but not through the second port of the nosecone which is relatively smaller in size. A guidewire may be also slidably positioned within at least a portion of the cannula passageway, and may be configured for passage through an inclined surface formed adjacent to the second port. The nosecone may further include imaging components or radiopaque markers that provides directional orientation.
Another embodiment of the invention provides a redirectable intravascular guidewire catheter. The catheter may be formed with a catheter shaft and a guidewire deflector formed at the distal end of the catheter shaft. The guidewire deflector may be formed as a nosecone assembly having a distal end port, a lateral port, and a relatively internal or external flapper assembly with a deflectable extension
Aguilar Amiel
Campello Mark
Co Fred
French Ronald
Milo Charles F.
LuMend, Inc.
O'Connor Cary
Wilson Sonsini Goodrich & Rosati
Wingood Pamela
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