A method of treating a lesion in a body lumen to enlarge a passageway in the lumen including providing a cutting member (20, 220a, 220b), connecting a tracking member (30, 230) to the cutting member to form an assembly (10), inserting the connected cutting member and tracking member through a first lumen of a catheter (100), withdrawing the catheter from the cutting member and tracking member, inserting the catheter over the tracking member and leaving the cutting member outside the catheter, and expanding a portion of the catheter to move the cutting member into cutting contact with the lesion. A device for treating a lesion in a body lumen including a cutting member having a coupler to connect a tracking member is also provided.
