[Determinant factors in the acute functional deterioration caused by the inhibition of the conversion enzyme in reno-vascular arterial hypertension].

Deterioration of renal function may be elicited by converting enzyme inhibition (CEI) in patients with bilateral (BI) or solitary kidney (SK) renal artery stenosis, but the determinants of this complication are not clearly delimited. The effect of acute administration of captopril on arterial pressure, glomerular filtration rate (GFR) and effective renal plasma flow was assessed in 10 BI and 10 SK hypertensive patients with a mean GFR of 64 +/- 5 ml/min. CEI induced a decrease in MAP of 8 +/- 2 p. 100 and a fall in GFR of 25 +/- 8 p. 100; GFR fell by more than 20 p. 100 in 5/10 BI and 8/10 SK. Filtration fraction (FF) decreased by 16 +/- 5 p. 100. CEI-induced change in GFR was not related to the change in MAP, but was inversely correlated with pre-C FF; GFR always fell when FF was higher than 0.28. Surgical correction of the stenosis suppressed the C-induced decrease in GFR in 5 SK patients in whom it initially fell. In conclusion, basal FF, a probable index of intrarenal angiotensin II activity, rather than a fall in systemic blood pressure, is the main predictor of acute deterioration of renal function after converting enzyme inhibition.