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. 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. 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.
Vascular disease, and atherosclerosis in particular, can be treated in a variety of ways, including drugs, bypass surgery, and a variety of catheter-based approaches. One catheter based approach is intravascular debulking or removal of the atheromatous or other material occluding a blood vessel. Of particular interest to the present invention, a variety of methods for cutting or dislodging material and removing such material from the blood vessel have been proposed, generally being referred to as atherectomy procedures. Atherectomy catheters intended to excise material from the blood vessel lumen generally employ a rotatable and/or axially translatable cutting blade which can be advanced into or past the occlusive material in order to cut and separate such material from the blood vessel lumen. In particular, side-cutting atherectomy catheters generally employ a housing having an aperture on one side and a blade which is rotated or translated past the aperture.
Although atherectomy catheters have been considered successful in treating many types of atherosclerosis and restenosis, improved atherectomy catheters and methods are continuously being pursued. For example, many currently available atherectomy catheters have cutters enclosed in relatively large diameter distal housings to assure that the cutter can be safely transported within the vessel. To provide storage capacity for sufficient volume of material while treating the vessel the cutter housings are often lengthened. It has also been proposed to combine imaging into atherectomy catheters. Imaging transducers, if provided, may impact the flexibility of the distal catheter region because the transducers are generally rigid. Decreased flexibility and increased length of the distal catheter region may make it more difficult to introduce and withdraw the distal end of the catheter through tortuous regions of the vasculature.
The present invention overcomes some of these problems associated with prior art devices. In particular, the present invention relates to methods and devices for imaging and removing tissue from a body lumen such as a blood vessel or other vascular location. Although the present invention may be used for removing material from a vascular location it may find uses in other body lumens as well. It is understood that although the invention may be described with respect to use in blood vessels the methods and devices of the present invention may be practiced in any body lumen.