CAPTOPRIL RENAL SCINTIGRAPHY IN RENOVASCULAR HYPERTENSION

Renovascular disease is a common cause of secondary hypertension. Rena l artery stenosis is present in up to one third of patients with clini cal markers suggestive of renovascular hypertension, such as hypertens ion refractory to medical management, severe hypertension in a young p atient and worsening of renal function after the use of an angiotensin -converting enzyme inhibitor. Early discovery of renal artery stenosis may allow amelioration or cure of the hypertension and halt progressi ve loss of renal function. Although renal arteriography remains the go ld-standard aid to diagnosis and to planning surgical intervention, it is an invasive procedure that may cause deterioration of renal functi on. In the presence of renal artery stenosis, glomerular filtration is maintained by angiotensin. Administration of captopril in renal scint igraphy removes this compensatory mechanism and causes a temporary imp airment of renal function in the affected kidney. Nuclear tracers can visualize this impairment, thus allowing assessment of the physiologic significance of a renal artery stenosis. The test can be done as a ou tpatient procedure.