EFFECT OF CHRONIC ACE-INHIBITION ON THE DIAGNOSTIC-VALUE OF RENOGRAPHY FOR RENOVASCULAR HYPERTENSION - A PRELIMINARY-REPORT

We compared the effects of acute and chronic ACE inhibition (ACEi) on the I-123-hippurate in the stenotic kidney of two 2-kidney, 1-clip hyp ertensive dogs. In the period after clip implantation poststenotic ren ograms without ACEi of both dogs were normal. Acute ACEi always result ed in delayed hippurate handling. Chronic ACEi, however, induced abnor mal poststenotic renograms in only 36% of the cases. Withdrawal of chr onic ACEi restored the phenomenon of acute ACE-induced delayed hippura te handling within 5 months in both dogs. These data indicate that chr onic ACEi or recent ACEi medication reduces the effectiveness of ACEi renography in diagnosing hypertension due to a moderate renal-artery s tenosis. This phenomenon may explain why the sensitivity of ACEi renog raphy in human studies varies more than in animal studies.