Studies assessing regional hemodynamics in patients with cirrhosis and ascites have shown vasodilation in the splanchnic circulation and vasoconstriction in the renal circulation and in the brachial and femoral artery vascular territories. The aim of this study was to assess the cerebral vascular resistance in cirrhotic patients with ascites. The resistive index in the middle cerebral artery (an index of the cerebral vascular resistance) and in a renal interlobar artery were measured by Doppler ultrasonography in 7 healthy subjects: 13 patients with compensated cirrhosis and 24 patients with ascites (13 with renal failure). The arterial blood pressure and the activity of the renin-angiotensin and sympathetic nervous systems, as estimated by plasma renin activity and plasma norepinephrine concentration, respectively, were also measured. The resistive index in the middle cerebral artery was significantly increased in patients with ascites (0.68 +/- 0.05, mean +/- SD) as compared with patients without ascites (0.60 +/- 0.01, P < .05) and with healthy patients (0.52 +/- 0.01, P < .01). Renal resistive index was also increased in patients with ascites (0.77 +/- 0.01) compared with the other two groups (0.68 +/- 0.02 and 0.62 +/- 0.00, respectively; P < .001). The resistive index in the middle cerebral artery showed a direct correlation with renal resistive index (r = .73, P < .01), plasma renin activity (r = .61, P < .01), and norepinephrine (r = .53, P < .01). The resistive index in the middle cerebral artery showed an inverse correlation with mean arterial pressure (r = -.45, P < .01). These results indicate that in patients with cirrhosis and ascites there is a cerebral vasoconstriction which is probably related with the arterial hypotension and the overactivity of vasoconstrictor systems.