Surgery – Instruments – Blood vessel – duct or teat cutter – scrapper or abrader
Reexamination Certificate
2000-08-22
2004-11-30
Reip, David O. (Department: 3731)
Surgery
Instruments
Blood vessel, duct or teat cutter, scrapper or abrader
C604S022000
Reexamination Certificate
active
06824550
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is generally related to medical devices, kits, and methods. More specifically, the present invention provides a system for crossing stenosis, partial occlusions, or total occlusions in a patient's body.
Cardiovascular disease frequently arises from the accumulation of atheromatous material on the inner walls of vascular lumens, particularly arterial lumens of the coronary and other vasculature, resulting in a condition known as atherosclerosis. Atheromatous and other vascular deposits restrict blood flow and can cause ischemia which, in acute cases, can result in myocardial infarction or a heart attack. Atheromatous deposits can have widely varying properties, with some deposits being relatively soft and others being fibrous and/or calcified. In the latter case, the deposits are frequently referred to as plaque. Atherosclerosis occurs naturally as a result of aging, but may also be aggravated by factors such as diet, hypertension, heredity, vascular injury, and the like.
Atherosclerosis can be treated in a variety of ways, including drugs, bypass surgery, and a variety of catheter-based approaches which rely on intravascular widening or removal of the atheromatous or other material occluding the blood vessel. Particular catheter-based interventions include angioplasty, atherectomy, laser ablation, stenting, and the like. For the most part, the catheters used for these interventions must be introduced over a guidewire, and the guidewire must be placed across the lesion prior to catheter placement. Initial guidewire placement, however, can be difficult or impossible in tortuous regions of the vasculature. Moreover, it can be equally difficult if the lesion is total or near total, i.e. the lesion occludes the blood vessel lumen to such an extent that the guidewire cannot be advanced across.
To overcome this difficulty, forward-cutting atherectomy catheters have been proposed. Such catheters usually can have a forwardly disposed blade (U.S. Pat. No. 4,926,858) or rotating burr (U.S. Pat. No. 4,445,509). While effective in some cases, these catheter systems, even with a separate guidewire, have great difficulty in traversing through the small and tortuous body lumens of the patients and reaching the target site.
For these reasons, it is desired to provide devices, kits, and methods which can access small, tortuous regions of the vasculature and which can remove atheromatous, thrombotic, and other occluding materials from within blood vessels. In particular, it is desired to provide atherectomy systems which can pass through partial occlusions, total occlusions, stenosis, and be able to macerate blood clots or thrombotic material. It is further desirable that the atherectomy system have the ability to infuse and aspirate fluids before, during, or after crossing the lesion. At least some of these objectives will be met by the devices and methods of the present invention described hereinafter and in the claims.
SUMMARY OF THE INVENTION
The present invention provides systems and methods for removing occlusive material and passing through occlusions, stenosis, thrombus, and other material in a body lumen. More particularly, the present invention can be used passing through stenosis or occlusions in a neuro, cardio, and peripheral body lumens. Generally, the present invention includes an elongate member that is positioned adjacent the occlusion or stenosis. A drive shaft having a distal tip is rotated and advanced from within the elongate member to create a path forward of the elongate member to form a path in the occlusion or stenosis. To facilitate passing through the occlusion or stenosis, the distal end of the elongate member can be steerable to provide better control the creation of the path through the occlusion or stenosis. Optionally, the target site can be infused and/or aspirated before, during, and after creation of the path through the occlusion.
In an exemplary embodiment, the elongate member is a hollow guidewire that has a flexibility, pushability and torqueability to be advanced through the tortuous blood vessel without the use of a separate guidewire. Additionally, the hollow guidewire may be sized to fit within a conventional support or access catheter system and inserted into the blood vessel and delivered to the target site. The catheter system can be delivered either concurrently with the advancement of the hollow guidewire or after the guidewire has reached the target site. The position of the hollow guidewire and catheter system can be maintained and stabilized while the drive shaft is rotated and translated out of the axial lumen of the hollow guidewire. The distal tip of the drive shaft can be deflected, coiled, blunted, flattened, enlarged, twisted, basket shaped, or the like. In some embodiments, to increase the rate of removal of the occlusive material, the distal tip is sharpened or impregnated with an abrasive material such as diamond chips, diamond powder, glass, or the like.
The drive shaft can be a counter-wound guidewire construction or be of a composite structure consisting of a fine wire around which a coil is wrapped. The counter-wound or composite constructions are more flexible than a single wire drive shaft and can provide a fighter bending radius while still retaining the torque transmitting ability so that it can still operate as a lesion penetration mechanism.
In a specific configuration, the drive shaft has spiral threads or external riflings extending along the shaft. The spirals typically extend from the proximal end of the shaft to a point proximal of the distal tip. As the drive shaft is rotated and axially advanced into the occlusive material, the distal tip creates a path and removes the material from the body. The rotating spirals act similar to an “Archimedes Screw” and transport the removed material proximally up the lumen of the elongate member and prevent the loose atheromatous material from escaping into the blood stream.
Systems and kits of the present invention can include a support system or access system, such as a catheter or guidewire having a body adapted for intraluminal introduction to the target blood vessel. The dimensions and other physical characteristics of the access system body will vary significantly depending on the body lumen which is to be accessed. In the exemplary case, the body of the support or access system is very flexible and is suitable for introduction over a conventional guidewire or the hollow guidewire of the present invention. The support or access system body can either be for “over-the-wire” introduction or for “rapid exchange,” where the guidewire lumen extends only through a distal portion of the access system body. Optionally, the support or access system can have at least one axial channels extending through the lumen to facilitate infusion and/or aspiration of material from the target site. Support or access system bodies will typically be composed of an organic polymer, such as polyvinylchloride, polyurethanes, polyesters, polytetrafluoroethylenes (PTFE), silicone rubbers, natural rubbers, or the like. Suitable bodies may be formed by extrusion, with one or more lumens that extend axially through the body. For example, the support or access system can be a support catheter, interventional catheter, balloon dilation catheter, atherectomy catheter, rotational catheter, extractional catheter, laser ablation catheter, guiding catheter, stenting catheter, ultrasound catheter, and the like.
In other embodiments, a hollow guidewire can be used as the support or access system. The hollow guidewire can be navigated to and positioned at the target site, with or without the use of a separate guidewire. The hollow guidewire support system provides the flexibility, maneuverability, torqueability (usually 1:1), and columnar strength necessary for accurately advancing through the tortuous vasculature. The hollow guidewire support system can act as a working channel inside of which other interventional devices can be delivered to the target site. Such d
Chechelski Victor
Noriega Gerardo V.
Sudaria Rudolfo
Nguyen Victor
Norbon Medical, Inc.
Reip David O.
Townsend and Townsend / and Crew LLP
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