Aspirin renography in the diagnosis of renovascular hypertension: a comparative study with captopril renography.

Captopril renography is used for the non-invasive diagnosis of renovascular hypertension, but suffers from the drawbacks of lower sensitivity and false-positive tests due to a fall in blood pressure. Aspirin renography has been proposed as a useful test for evaluation of unilateral renal artery stenoses of moderate degree. We studied the clinical usefulness of aspirin renography in 12 patients with a clinical suspicion of renovascular hypertension and compared it with captopril renography using 99Tcm-DTPA. The test was considered positive if there were changes in the time-activity curve according to the criteria specified by the American Society of Hypertension Working Group. Four patients with discordant results between captopril and aspirin underwent intra-arterial digital subtraction angiography. In two patients, the renal arteries were normal; captopril was false-positive in both these patients. Bilateral stenosis was noted in the third patient, with captopril being false-negative on the right side with moderate stenosis, whereas aspirin was true-positive. There was unilateral stenosis in the fourth patient; captopril was false-positive on the contralateral side. Our results suggest that aspirin renography is superior to captopril renography in the assessment of patients with a suspicion of both unilateral and bilateral renovascular hypertension.