Renal venous samples during active renin secretion in the prognosis of surgery for renovascular hypertension

The authors take into consideration the conditions in which the renin secretion is low (inactive or declining phase) in patients with renovascular or renal hypertension. In such conditions a number of false negative results are present which diminish considerably the diagnostic value of renin determination in the renal veins and in the lower inferior vena cava. In order to improve the diagnostic accuracy, the authors suggest to take blood samples after acute drug induced hypotension when the renin secretion is more active. In doing so it has been shown that the renin activity on the affected kidney becomes much higher than on the contralateral side, and therefore the RVRR becomes higher than it was in basal condition. Some patients with renovascular hypertension cured by surgery, who had a ratio lower than 1.5 in basal condition (declining phase of renin secretion) become positive (ratio higher than 1.5) after drug acutely induced hypotension (active phase of renin secretion).