Abstract: Self-centering valvulotome (V) having a flexible cable (1) partly and slidably disposed within a protective sheath (2), a cutting unit (4), having at least three radially mounted, retractable cutting blades, attached to the cable at its distal end, and a dual-purpose control mechanism attached to the cable at its proximal end. Each retractable cutting blade comprises a free-floating cutting head and a flat spring section, which biases the cutting head against the venous wall. The control mechanism comprises a T-valve segment disposed partly within the proximal end of the protective sheath. A pull handle affixed to the proximal end of the cable can engage the T-valve such that a fluid-tight seal is created, thereby allowing the introduction of a diagnostic or therapeutic fluid to the protective sheath via an access port in the valve.