Methods and devices for separating an implanted object, such as a pacemaker lead, from tissue surrounding such object in a patients vasculature system. Specifically, the tissue separating device includes a handle, an elongate sheath and a circular cutting blade that may extend from the distal end of the sheath upon actuating the handle. The circular cutting blade is configured to engage the tissue surrounding an implanted lead and cut such tissue in a coring fashion as the device translates along the length of the lead, thereby allowing the lead, as well as any tissue remaining attached to the lead, to enter the devices elongate shaft. The tissue separating device includes a cam mechanism at the distal portion of the sheath that allows the user of the device to more accurately control the extension and rotation of the cutting blade upon being actuated by the handle.