In many patients with peripheral vascular disease, conventional arteriograms are not adequate to make proper preoperative decisions. In the past, these inadequate studies led to surgical exploration of vessels and intraoperative angiography to determine operability. Such efforts prolonged operating time and potentially had adverse effects on amputation levels. Recently, intra-arterial digital subtraction angiography (IDSA) has provided an excellent means to further evaluate these patients preoperatively. We presently have 30 patients in whom IDSA supplemented routine aortography and runoff studies. When standard angiographic studies were considered inadequate, the catheter was positioned appropriately and IDSA was obtained. Inadequate lower extremity distal runoff in 23 patients and no proximal or distal runoff in seven patients prompted the IDSA. The IDSA study yielded further information on all patients, and 26 of 30 patients underwent successful bypass operation. In all 17 patients having femoropopliteal or femorotibial bypass, the IDSA was confirmed by an intraoperative (after bypass) angiogram. Nine patients had inflow procedures, and operative findings corroborated the IDSA. Two patients refused surgery and two patients were not candidates for revascularization. The IDSA study provided an accurate "road map," eliminated unnecessary vessel exploration, saved vital operative time, and prevented compromise of potential amputation levels.