Proper selection of suprainguinal vs. infrainguinal arterial revascularization in patients with multilevel disease requires hemodynamic assessment. In such patients hemodynamic evaluation of the aortoiliac system cannot be made accurately with either arteriography or current noninvasive techniques. One hundred six lower extremities underwent preoperative triplane arteriography, measurement of Doppler-derived segmental blood pressures, measurement of common femoral intra-arterial pressure, and intra-arterial injection (30 mg) of the vasodilator papaverine hydrochloride prior to arterial bypass. Common femoral intra-arterial pressure was monitored continuously before and after papaverine injection. The resting femoral/brachial pressure index (FBI) and the maximum change in this index (% delta FBI) following papaverine injection were calculated. To be considered improved postoperatively, claudicants required an increase in treadmill walking time of greater than or equal to 50%, whereas patients operated on for limb salvage required an increase in the thigh/brachial pressure index (TBI) of greater than or equal to 0.15 for suprainguinal revascularizations and an increase of TBI to greater than or equal to 0.9 for infrainguinal revascularizations. In the first 41 extremities (phase I), receiver operator characteristic analysis revealed a % delta FBI greater than or equal to 15% to be optimal in the detection of hemodynamically significant aortoiliac disease. In phase II (65 limbs) this discriminant value for % delta FBI was assessed prospectively. In phase I, in which the choice of supra- vs. infrainguinal bypass was determined arteriographically, only 80% of the extremities were improved; in phase II, in which supra- vs. infrainguinal bypass was determined by the papaverine test, 98% of extremities were improved (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)