Angiotensin II analogue infusion test in renovascular hypertension under low sodium intake and under spironolactone administration: is angiotensin II analogue infusion test useful in determining the mode of treatment?

An angiotensin II antagonist (1-Sar, 8-Ileu-angiotensin II) was infused into 5 hypertensive patients with unilateral renal artery stenosis under 5-day low sodium diet (2 g NaCl/day) and under 7-day spironolactone administration (300 mg/day). In the sodium depleted state, 1 case showed depressor response, 2 cases pressor response and the other 2 no response. During the spironolactone administration, 3 cases showed depressor, 1 case pressor, and another case no response. Angiotensin II analogue (A II A) infusion test under spironolactone administration was more effective than under sodium depletion. However, there were cases which showed pressor response, i.e. false negative, under low sodium diet and under spironolactone administration. The hypertension of these patients was cured by converting enzyme inhibitor, percutaneous transluminal renal angioplasty (PTRA) or bypass surgery. A II A infusion test has been used for screening, diagnosis and determination of the surgical repair of renovascular hypertension. However, the proportion of depressor response was low in our cases, yet pressor responders and non-responders were also cured by PTRA. PTRA is a painless and low risk procedure of the treatment of renovascular hypertension, so PTRA will become the preferential mode of therapy for the treatment of renovascular hypertension of the cases with no depressor response by AIIA infusion.