Abstract: A blade is drawn by means of a rod attached centrally of its cutting edge so that a portion of the blade extends on either side of the rod. An elongate centering device precedes the blade and its protective encasement so as to ensure that the device will not engage side branches of the vein. A catheter follows the valve cutter so that fluid may be introduced into the vein to snap valves shut ahead of the cutting device. The assembly is drawn through a vein by a rod having sufficient torsional rigidity to permit controlled orientation of the blade for efficient engagement and cutting of valve leaflets.