Surgery – Instruments – Internal pressure applicator
Reexamination Certificate
2001-07-25
2003-03-18
Milano, Michael J. (Department: 3731)
Surgery
Instruments
Internal pressure applicator
C606S200000, C606S159000
Reexamination Certificate
active
06533800
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to devices and methods useful in treating patients with occlusive vascular disease. More specifically, the invention provides devices capable of reversing blood flow in a first artery so that blood flows into a second artery during an invasive procedure, thereby avoiding distal embolization of vascular debris in the first artery.
BACKGROUND OF THE INVENTION
Collateral channels are present in arterial, venous, and lymphatic circulation throughout the body. Collateral circulation is established through connection(s) or anastomoses between two vessels supplying or draining two adjacent vascular regions. Blood supply to an organ is maintained through these collateral channels when the main vessel is obstructed. Collateral circulation, therefore, provides a compensatory mechanism that allows amelioration of the detrimental effect of blood flow cessation due to obstruction of a vascular pathway.
The areas of the body where collateral blood flow is of particular importance are that of the cerebral and coronary circulation where interruption or cessation of blood supply to the brain or the heart may be have devastating consequences, e.g., causing stroke or myocardial infarction. Collateral circulation is also present in the extremities. Occlusion of blood supply to the extremities is usually due to atherosclerosis. Clinical symptoms depend upon the extent of obstruction, the rate of progression, the vessels involved, and whether collateral flow exists.
Current treatment of vascular occlusive disease includes percutaneous transluminal angioplasty (PTCA), thromboendarterectomy, bypass graft using woven prosthetic tube or autogenous vein anastomosed end-to-side to the vessel above and below the obstruction, or resection with graft replacement. Unfortunately, one common complication is distal embolization of vascular debris, e.g., calcium, atheromatous plague, thrombi, fat, and vascular tissue, generated during the procedures. Distal embolization of debris to a coronary artery can cause further myocardial ischemia and infarction. Embolization of debris to the distal extremities may cause gangrene of the toes and foot.
New devices and methods are thus needed for patients undergoing vascular procedures for treatment of occlusive vascular disease, devices that minimize the risk of distal embolization and end organ damage.
SUMMARY OF THE INVENTION
The invention provides devices and methods for preventing organ ischemia and infarction in patients undergoing vascular procedures, including angioplasty, stent placement, and/or filter insertion, by reversing blood flow from a first artery, vein, or lymphatic duct, into a second artery by use of collateral circulation. In this way, embolic debris generated as a result of placing instrumentation within a diseased first vessel is diverted to the second vessel, thereby minimizing embolization to the distal vessels supplied by the diseased vessel. It will be understood that the devices and methods disclosed herein are useful in any region of the body where flow reversal is possible.
The invention utilizes devices comprising a catheter having one or two expandable constricting members at a distal region. Each constrictor may be a balloon, in certain cases a toroidal balloon, or a device of any other appropriate shape, so that it can fully or partially obstruct blood flow. The lumen of the catheter may be adapted for insertion of a therapeutic instrument, such as an angioplasty, atherectomy, and/or stent catheter. A manometer is optionally mounted proximal and/or distal to the constricting member for monitoring blood pressure proximal and/or distal the constrictor.
The terms obstruction, occlusion, and constriction are used interchangeably herein to refer to partial or complete blockage of a vessel, and to any of the devices that provide such blockage. The devices comprise an obstructing, occluding, or constricting mechanism, in certain cases a balloon, distally mounted on a catheter for delivery to a vessel, such as the left main coronary artery. The obstructor, occluder, and/or constrictor is collapsed to facilitate insertion into and removal from the vessel, and expanded during use to at least partially obstruct blood flow.
The occluder-constrictor is mounted near the distal end of the catheter, in certain cases proximal to a port. Each balloon occluder and constrictor communicates with an inflation lumen and an inflation port at the proximal end of the catheter. In certain embodiments, the catheter will include first and second constriction/occlusion members. The second constrictor may be mounted on a second member that is slideably insertable through the catheter, and passes beyond the first constrictor. In this way, the second member and the second constrictor are moveable longitudinally relative to the first constrictor. In other embodiments, the constrictor may comprise a balloon having one or more than one opening at its center for the passage of blood, or may consist of more than one expandable balloons allowing passage of blood through the gap or gaps between the arterial wall and the expanded balloons. The proximal end of the catheter may include a hemostatic valve.
In still another embodiment, the catheter includes a second lumen communicating with a proximal end and an infusion port at its distal end. The port is located distal to the distal port of the catheter. The second lumen and its port are adapted for delivering a pharmaceutical agent to the carotid, coronary, iliac, brachiocephalic and/or subclavian arteries, including an angiographic dye. Any devices and methods described in Barbut, U.S. Pat. No. 6,146,370, and in U.S. application Ser. No. 09/792,732, filed Feb. 23, 2001; Ser. No. 09/792,600, filed Feb. 23, 2001; and Ser. No. 09/847,425, filed May 1, 2001, all incorporated herein by reference in their entirety, may also be used in the procedures described herein.
The catheters may be used anywhere in the body for flow reversal in an artery, vein, or lymphatic duct having a proximal segment that branches into first and second distal segments. The vessels are selected so that the first distal segment has a source of collateral blood or lymphatic flow and typically will also have a lesion. The distal end of the catheter is inserted into the proximal segment. The expandable device is located within the proximal segment. The expandable constricting-occluding device is expanded to at least partially obstruct the proximal segment. This causes flow to reverse in the first distal segment and to pass over the lesion and toward the second distal segment.
In one application, the invention provides methods for reversing flow from a coronary artery having an atheromatous lesion into another coronary artery. For example, the methods are useful in reversing flow from an occluded left anterior descending (LAD) artery and into the left circumflex (LCx) artery. Using the devices described above, the distal end of the catheter is inserted into the left main coronary artery which branches into the LAD and LCx arteries. The catheter can be inserted over a guidewire through an incision on a peripheral artery, including the femoral artery, the subclavian artery, or the brachial artery. The catheter is positioned to locate the constricting member within the left main coronary artery. The constrictor is expanded to completely or partially occlude the left main coronary artery. At a critically low pressure distal to the constriction, blood flow in the LAD artery is reversed to pass over the atheromatous lesion and into the LCx artery. This reversal occurs because the LAD receives collateral blood flow from other coronary arteries downstream of the occlusion. The flow reversal can be verified fluoroscopically with dye. If flow reversal fails to occur or if augmentation of flow reversal is desired, a second constricting member is expanded in the LCx artery, further reducing the LCx distal pressure and enhancing reversal of flow to the LCx. A blood filter may be inserted through the catheter and de
CoAxia, Inc.
Milano Michael J.
O'Melveny & Myers LLP
Webb Sarah
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