A catheter having a tubular body and a rotatable shaft disposed within a lumen of the tubular body. A cutting element is coupled to the rotatable shaft, the cutting element having a cutting edge, the cutting element and rotatable shaft being longitudinally moveable within the tubular body between a stored position in which the cutting element is parallel a longitudinal axis of the tubular body and a cutting position in which the cutting element is deflected between the proximal and distal ends of the tubular body to extend beyond an outer diameter of the tubular body. The cutting element is configured to cut material from the wall of a vessel at a treatment site as the catheter is pushed distally through the treatment site. The catheter includes a collection chamber positioned proximally of the cutting window.
