Captopril renography for the detection of renovascular hypertension

ABSTRACT

The effect of a provocative challenge with an angiotensin-converting enzyme inhibitor (captopril) upon technetium-99m-labeled diethylene triaminepentaacetic acid (Tc-99m-labeled DTPA) and iodohippurate sodium 1-131 (1-131 Hippuran) renograms was studied in a group of 16 selected hypertensive patients. The patients were categorized as having either renal artery stenosis (RAS, n= 11) or essential hypertension (EHT, n=5) based upon renal angiographic findings. In patients with RAS, captopril altered the time-activity curves of the stenotic kidney(s) of both radionuclide studies and improved the diagnostic sensitivity. In patients with EHT, captopril did not alter the radionuclide studies. Converting-enzyme inhibition coupled with noninvasive radionuclide studies of the renovascular bed offers promise in improving the sensitivity and specificity for detecting hemodynamically significant RAS in the hypertensive population.