Renography with captopril. Changes in a patient with hypertension and unilateral renal artery stenosis

In a 56-year-old man with severe familial hypertension and unilateral renal artery stenosis, captopril induced striking changes in the renograms of the affected kidney. After injection of orthoiodohippurate sodium I 131, the uptake phase was unchanged but the later curve showed continuous accumulation. In contrast, the uptake of technetium Tc 99m diethylenetriamine pentracetic acid was abolished. These changes are compatible with a cessation of filtration and maintenance of renal blood flow. After balloon dilatation of the stenosis, the blood pressure became lower, and these changes could no longer be demonstrated. The captopril renogram may provide useful information on the dependency of hypertension on unilateral renal artery stenosis.