Atherectomy catheter devices having a C-shaped balloon opposite a cutting window out of which a rotating cutter may extend and a proximal annular balloon. The C-shaped first balloon may be used to drive the cutter against a vessel and to deploy the cutter by assisting in deflecting a nosecone (distal tip) to expose the distal-facing cutting edge of the cutter. The proximal annular balloon may be used to occlude blood flow. The device may pulled, pushed or rotated in a vessel with the balloons inflated or deflated.
