Adenosine-induced renal vasodilatation is prolonged in renal artery stenosis

Objective The objective of this study was to determine whether the response of renal blood flow (RBF) to adenosine infusions differs between hypertens ive patients with and without renal artery stenosis (RAS). Design and Methods Twenty-one hypertensive patients who underwent diagnosti c angiography of the renal arteries were studied. Nine patients (median age 51 years; 45-61 interquartile ranges) were diagnosed as having essential h ypertension (EH). Twelve patients (median age 52 years; 50-58) had hyperten sion and renal artery stenosis. In all patients three stepwise increasing d oses of adenosine (1, 3 and 10(mu g/kg/min) were infused into the renal art ery. RBF was measured before and during infusions by means of the (133)xeno n wash-out method. Arterial and venous plasma samples for renin concentrati on were obtained from the renal artery and renal vein. Intraarterial blood pressure end heart rate were monitored continuously. Results Both groups were similar with respect to age, body mass index, mean arterial pressure and baseline RBF (EH: median 428; RAS 343 ml/min/100 g). Both groups showed a similar dose-related increase in RBF during adenosine infusions (normal kidneys: 9, 21 and 34% change vs baseline; stenotic kidn eys: 16, 39 and 52% change vs baseline). Ten minutes after discontinuation of the adenosine infusion, RBF returned to baseline in the normal kidney gr oup, but increased further in the stenotic kidney group (71% vs baseline; P = 0.033) Adenosine infusion did not affect the renin secretion in either g roup. Conclusion Both essential hypertensive patients and patients with renal art ery stenosis show a dose-dependent: vasodilatation following adenosine infu sion. This vasodilatation is sustained after discontinuation of the adenosi ne infusion in patients with renal artery stenosis, suggesting a potentiate d mechanism for vasodilatation induced by adenosine, J Hypertens 1998, 16:2 109-2112 (C) 1998 Lippincott Williams & Wilkins.