Hypotensive response to captopril: a potential pitfall of scintigraphic assessment for renal artery stenosis

A characteristic pattern seen on captopril renography is described that is due to systemic hypotensive response. Most patients with these findings on captopril renography do not receive renal artery angiograms in our clinic because it is usually recognized. However, this pattern has received little attention in the medical literature and may be misinterpreted as being due to physiologically significant renal artery hypertension.

Over the last 3 y, renal artery angiograms were performed on three patients with systemic hypotensive response pattern on captopril renography. This allowed a unique opportunity to correlate the results of the captopril renogram with the renal artery angiograms in this patient population. Captopril renography was performed with a glomerular filtration agent, diethylenetriamine pentaacetic acid (DTPA), and a tubular agent, o-iodohipurate (OIH).

Renal artery angiograms showed no evidence of renal artery stenosis in three patients with systemic hypotensive response pattern on captopril renography. Systemic hypotension on captopril renograms results in preserved uptake of both DTPA and OIH and hyperconcentration in the cortex and collecting system.

The systemic hypotensive response pattern seen on captopril renography is a distinctive pattern that does not represent physiologically significant renal artery stenosis.