Ultrasonic energy has been shown to ablate atherosclerotic plaques and arterial and venous thrombi. We used an ultrasonic angioplasty device developed by our group in ten patients with totally occluded femoral artery during surgical bypass. Ultrasonic angioplasty was performed with a 130-cm long and 0.8-cm diameter titanium probe with a 2- or 2.5-mm titanium ball-tip. In one patient, angioplasty could not be performed. Angiographic and angioscopic examination were performed before and after angioplasty in nine patients. Before ultrasound recanalization, angioscopic examination showed that the proximal end of the occlusion was formed by atheromatous material in 3 cases, red thrombus in 3 cases, amd white thrombus in 3 cases. After ultrasound recanalization, angioscopy showed residual stenosis at the site of entry in only one case. In three other cases, the artery was free of residual stenosis without persistent clot. In the five other patients, a residual stenosis was present beyond the proximal occlusion point with some fibrin mesh and small clots. At angiography, flow was restored in 4 cases; in 4 patients flow rate of entry was slow in the distal segment; and in 1 patient, the distal arterial bed could not be opacified. Altogether, ultrasonic angioplasty was able to recanalize a complete occlusion in nine out of ten patients, with partial or complete dissolution of clots and with no complication. At its present stage of development, adjunctive balloon angioplasty would be needed in most cases to obtain unrestricted flow and unsignificant residual stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)