A catheter (2A, 2B, 2C) for removing material from a body lumen comprising: a tubular body having proximal and distal ends and a side opening positioned proximal of the distal end of the tubular body; a rotatable shaft disposed within the lumen of the tubular body, the rotatable shaft having proximal and distal ends; a cutting element coupled to the rotatable shaft for rotation about an axis of rotation, the cutting element having a cutting edge; a cam follower secured to the rotatable shaft adjacent the proximal end of the rotatable shaft; and a handle (5A, 5B) attached to the tubular body adjacent the proximal end of the tubular body, the handle (5A, 5B) including a motor, and a cylindrical cam coupled to the motor and to the cam follower (26, wherein the cutting element and the rotatable shaft are longitudinally moveable within the tubular body between a stored position, in which the cutting element is received in the tubular body, and a cutting position, in which at least a portion of the cutting edge extends through the side opening, the motor is configured to transmit rotation to the cylindrical cam to both impart translation to the cam follower to move the cutting element from the stored position to the cutting position, and thereafter impart rotation to the cam follower when the cutting element is in the cutting position to rotate the cutting element about its axis of rotation; the catheter (2A, 2B, 2C) further comprising: a ramp (16a, 16b, 16c) coupled to the tubular body adjacent the distal end of the body and having an angular surface generally opposite the side opening; wherein the cutting element comprises a flexible cutting element having a longitudinal axis, and a distal tip having the cutting edge, the flexible cutting element configured to engage the angular surface of the ramp (16a, 16b, 16c) and deflect along its longitudinal axis such that at least a portion of the longitudinal axis of the cutting element is not parallel to the longitudinal axis of the tubular body and at least a portion of the cutting edge extends through the side opening beyond the outer diameter of the tubular body. a tubular body having proximal and distal ends and a side opening positioned proximal of the distal end of the tubular body; a rotatable shaft disposed within the lumen of the tubular body, the rotatable shaft having proximal and distal ends; a cutting element coupled to the rotatable shaft for rotation about an axis of rotation, the cutting element having a cutting edge; a cam follower secured to the rotatable shaft adjacent the proximal end of the rotatable shaft; and a handle (5A, 5B) attached to the tubular body adjacent the proximal end of the tubular body, the handle (5A, 5B) including a motor, and a cylindrical cam coupled to the motor and to the cam follower (26, wherein the cutting element and the rotatable shaft are longitudinally moveable within the tubular body between a stored position, in which the cutting element is received in the tubular body, and a cutting position, in which at least a portion of the cutting edge extends through the side opening, the motor is configured to transmit rotation to the cylindrical cam to both impart translation to the cam follower to move the cutting element from the stored position to the cutting position, and thereafter impart rotation to the cam follower when the cutting element is in the cutting position to rotate the cutting element about its axis of rotation; the catheter (2A, 2B, 2C) further comprising: a ramp (16a, 16b, 16c) coupled to the tubular body adjacent the distal end of the body and having an angular surface generally opposite the side opening; wherein the cutting element comprises a flexible cutting element having a longitudinal axis, and a distal tip having the cutting edge, the flexible cutting element configured to engage the angular surface of the ramp (16a, 16b, 16c) and deflect along its longitudinal axis such that at least a portion of the longitudinal axis of the cutting element is not parallel to the longitudinal axis of the tubular body and at least a portion of the cutting edge extends through the side opening beyond the outer diameter of the tubular body.