EFFECTS OF BETA-ADRENOCEPTOR ANTAGONISTS ON CEREBRAL BLOOD-FLOW OF CIRRHOTIC-PATIENTS WITH PORTAL-HYPERTENSION

The current study evaluated the effect of two beta adrenergic-blocking agents, propranolol (PRP) and atenolol (ATN), versus placebo on cerebral blood flow (CBF) of three homogeneous groups of cirrhotic patients with portal hypertension. CBF was measured by the noninvasive 133-Xenon inhalation method at rest and 1 hour after a single oral dose of PRP (40 mg), or ATN (100 mg), or placebo. Blood pressure and heart rate (HR) were measured at the beginning of each examination, and end-tidal pCO2 (PeCO2) was monitored. The HR decreased significantly in both the PRP and ATN groups (P < .01), whereas no changes were recorded for both PeCO2 and mean arterial blood pressure (MABP). The comparisons of the CBF differences among groups (ANOVA with the significance levels adjusted by the Bonferroni's correction) showed a significant increase in CBF after ATN as compared with both placebo (P < .02) and PRP (P < .01), whereas no significant differences were seen after PRP as compared with placebo. Our results confirm that PRP does not significantly affect CBF, whereas ATN induces an increase in CBF, although the underlying mechanism is difficult to explain.