RENAL SCINTIGRAPHY AFTER THE ADMINISTRATI ON OF CAPTOPRIL - CLINICAL-EXPERIENCE IN THE EVALUATION OF THE HYPERTENSIVE PATIENT

BACKGROUND: Isotopic renogram allows renal function to be estimated in both kidneys independently. The glomerular filtrate in ischemic kidne ys is largely dependent on the tone of the efferent glomerular arterio lae and therefore on the concentration of circulating angiotensin II. METHODS: In 42 patients with severe high blood pressure in whom renal angiographic study was carried out for suspicion of vasculorrenal hype rtension, an Isotopic renogram using 99m Tc-DTPA as a tracer was perfo rmed in basal conditions and following the administration of 50 mg of oral captopril. RESULTS: In 21 patients both the angiographic examinat ion and the postcaptopril renogram were normal. In 16 patients in whom uni or bilateral stenosis higher than 50 % of the lumen of renal arte ry was observed on angiographic examination, the post captopril renogr am showed changes. In 5 patients the angiography was normal while the renogram showed evaluable changes. No false negatives were observed in the postcaptopril renogram, however the basal renogram was not demons trative in 6 patients with stenosis of the renal artery. Sensitivity o f the test was thus 100 % and specificity 80 %. The positive predictiv e value was 76 % and the negative predictive value 100 %. CONCLUSIONS: The post-captopril renogram may be a useful test in the functional st udy of renal behavior in patients with vasculorrenal hypertension.