Captopril Renography in the Diagnosis of Renovascular Disease

Several investigators have reported methods for the use of renal scintigraphy in the diagnosis of renal artery stenosis. We report the experience of Duke University Medical Center, and offer some suggestions for standardizing and optimizing the use of this potential screening tool. We evaluated 140 clinically selected hypertensive adults with postcaptopril renal scintigraphy (renography), pre- and postcaptopril peripheral renin activity, and conventional renal arteriography. Postcaptopril renography (using 99mTc-diethylenetriaminepentaacetic acid (DTPA) to measure glomerular filtration and [131I]iodohippurate to measure renal plasma flow) was considered abnormal if one kidney contributed 47% or less of total activity. Postcaptopril renin was considered elevated if it was at least 4 ng/mL/h. Renovascular disease was defined as 50% or greater main renal artery stenosis. Of 140 subjects, 31 (22%) had significant renovascular disease. Captopril-stimulated DTPA renography suggested asymmetric function in 24 (74%) of these, but was also abnormal in 61 of 109 (56%) with normal renal arteries. Captopril-stimulated hippuran renography performed in a similar manner. Captopril-stimulated renin activity was elevated in only 58% of subjects with renal artery stenosis, and had a false positive rate of 24%. These data differ from reports from other centers, perhaps due to differences in renography methods, criteria for interpretation of renography, and/or patient selection criteria.