Ischemic stroke represents a leading cause of death in patients with renovascular hypertension. In the vast majority it is related to obstructive lesions of the extracranial tracts of the carotid arteries. Since no data were previously available on carotid artery lesions in patients (pts) with renovascular hypertension, a prospective case-control study was undertaken to assess the prevalence of carotid artery lesions in renovascular hypertension. Nineteen pts (10 females and 9 males, age: 26-77 yrs) with a diagnosis of renovascular hypertension based on the presence of uni- or bilateral renal artery stenosis and favourable outcome after either percutaneous transluminal renal angioplasty or surgery, and/or renal vein studies, were evaluated. The cause of renal artery stenosis was atherosclerosis in 12 pts and fibrodysplasia in 7. Each pt was matched with a control pt with primary hypertension for sex, race, age, blood pressure levels, smoking habits and serum cholesterol levels. Carotid artery lesions were assessed using a high resolution echo-Doppler (Duplex) system (Biosound 2000, probe 4 cm, 8 mHz). After the matching, the two groups were almost identical in terms of demographic features and risk profile. In the control group the prevalence of carotid artery lesions was similar to that reported in the literature. On the contrary, a highly significant higher prevalence of carotid artery lesions was observed in the pts with renovascular hypertension (92.1 vs 42.1%, respectively; p less than 0.001). Subgroup analysis showed that this difference was found mainly in pts with atherosclerotic renal artery stenoses.(ABSTRACT TRUNCATED AT 400 WORDS)