Daily variation of azygos and portal blood flow and the effect of propranolol administration once an evening in cirrhotics

Background/Aims: Esophageal variceal bleeding occur more often at night, ho wever, the mechanism for this remains unclear. This study investigated the daily variation of azygos blood flow (AzBF) and portal blood flow (PBF) and the effects of propranolol administration given once in evening in cirrhot ics. Methods: Blood flow were measured using magnetic resonance imaging. Hemodyn amic parameters were determined at 08:00, 16:00 24:00 and again 08:00 h, an d were measured at baseline and after 14 days oral administration of propra nolol (30 mg, n = 7) or placebo (n = 7) at 19:00 h in 14 patients. Results: A daily fluctuation of AzBF and PBF was observed, peaking at 24:00 h in nine patients. In three other patients, peak AzBF and PBF were observ ed both at 16:00 and 24:00 h. Two patients were constant throughout the day . When the daily variation was compared, ANOVA showed a significant differe nce (P < 0.001). Propranolol administration at 19:00 h reduced AzBF (-40.7 +/- 17.9% vs, baseline, P < 0.001) and PBF (-26.5 +/- 10.7% vs, baseline, P < 0.01) at 24:00 h. Conclusions: We found that in most cirrhotics, AzBF and PBF peaks at midnig ht. Dosing of propranolol in the evening may be important for its role in p reventing variceal bleeding. (C) 2001 European Association for the Study of the Liver. Published by Else vier Science B.V. All rights reserved.