Ninety seven patients (mean age: 58 years) with lesions involving the subclavian artery were studied to determine the relationship between clinical symptoms, angiographic lesions and Doppler-detected hemodynamic disorders. Ninety patients had vertebro-basilar insufficiency (VBI) and 7 had hemispheric manifestations or upper limb ischemia. Of the 105 lesions of the subclavian artery, we observed 76 stenoses greater than 50% and 29 complete occlusions. Thirty seven patients presented a unilateral subclavian lesion and 63 multiple lesions. Doppler examination of the vertebral artery including an upper limb hyperaemic test allowed classification of the patients into three stages: stage 1 "pre-subclavian steal" (35 patients): sudden decrease in the systolic vertebral flow with complete interruption during hyperaemia; stage 2 "intermittent subclavian steal" (18 patients): transient inversion of vertebral during systole with permanent inversion for 1 or 2 minutes after hyperaemia; stage 3 "permanent subclavian steal" (33 patients): complete inversion of the vertebral flow without diastolic flow and increase of flow during hyperaemia. The clinical, hemodynamic and angiographic findings were compared. In stage 1, 65.7% of the patients presented severe VBI (at least two signs) and 66% had a 50 to 70% stenosis of the subclavian artery. In stage 2, 66.6% of the patients presented severe VBI and 78% had a 75 to 95% stenosis. In stage 3, 72.7% of the patients had severe VBI and 73% had either subtotal or complete occlusion of the subclavian artery. There was no correlation between the severity of VBI and the hemodynamic stages but a strong correlation between the hemodynamic grades and the anatomical lesions.(ABSTRACT TRUNCATED AT 250 WORDS)