RESUMEN
BACKGROUND/AIMS: Portal hypertension in cirrhosis is associated with a hyperdynamic circulation, which is characterized by hypervolemia, high cardiac output, arterial hypotension and low peripheral vascular resistance. These circulatory abnormalities are thought to be secondary to a splanchnic arteriolar vasodilation related to the increase in portal pressure. Studies assessing regional hemodynamics in patients of cirrhosis with ascites have shown vasoconstriction in the renal circulation and in peripheral vascular territory. This study was designed to assess the cerebral vascular resistance in cirrhotic patients with ascites. METHODS: The resistive index in the middle cerebral artery and in a renal interlobar artery were measured by Doppler ultrasonography in 12 cirrhotic subjects without ascites, 23 cirrhotic subjects with ascites, and 8 healthy subjects. The arterial blood pressure and plasma renin and norepinephrine concentration, which reflect the activity of the renin-ngiotensin and sympathetic nervous systems respectively, were also measured. RESULTS: The resistive index in the middle cerebral artery were significantly higher in cirrhotic patients with ascites (0.58 +/- 0.04, mean +/- standard deviation) than in cirrhotic patients without ascites (0.53 +/- 0.02, p<0.01) and in control subjects (0.50 +/- 0.05, p<0.01). The resistive index in the middle cerebral artery showed direct correlation with renal resistive index (r = 0.52, p<0.01), plasma renin activity (r = 0.44, p<0.01) and norepinephrine (r = 0.33, p<0.05). The resistive index in the middle cerebral artery showed an inverse correlation with mean arterial pressure (r = -.59, p<0.01). CONCLUSION: The results suggest that in patients of cirrhosis with ascites, independent of the amount of ascites, there is a cerebral vasoconstriction which is related with the arterial hypotension and the overactivity of vasoconstrictor systems.