DIURNAL FLUCTUATIONS OF PORTAL AND SYSTEMIC HEMODYNAMIC PARAMETERS INPATIENTS WITH CIRRHOSIS

A close temporal relationship between higher levels of portal pressure during the night and the peak incidence of acute variceal bleeding ha s recently been demonstrated in patients with cirrhosis. Because hemod ynamic changes may have a role in triggering this hemorrhagic episode, we measured systemic and portal hemodynamic parameters at 4-hr interv als for 24 hr in 12 cirrhotic patients. These results were compared wi th those obtained in eight healthy subjects. Cardiac output, femoral a nd portal blood flows were measured by Doppler technique. In cirrhotic patients, heart rate and mean arterial pressure remained constant thr oughout the whole study period. A marked and significant increase in p ortal blood flow (917 +/- 248 ml/min) (mean +/- S.D.) as compared with mesor values (649 +/- 114 ml/min, p < 0.001) was observed at midnight . This effect was accompanied by a mild but significant rise of cardia c output (from 6.5 +/- 0.7 to 6.8 +/- 0.7 l/min, p < 0.01) at 2400 hr. A significant correlation between both hemodynamic parameters was fou nd (r = 0.78, p < 0.01). Cosinor analysis showed a significant (p < 0. 05) circadian rhythm for both portal blood flow and cardiac output wit h an acrophase at 0050 hr. In the healthy subjects group, a significan t decrease of mean arterial pressure and heart rate was observed at 24 00 hr. Cosinor analysis confirmed the presence of significant rhythm f or both hemodynamic parameters. In contrast with cirrhotic patients, n o significant changes were observed in portal blood flow and cardiac o utput in healthy subjects. Our results show that in patients with cirr hosis, maximal increases in portal blood flow occur at night. The circ adian variation of portal blood how could have important implications in the management of these patients.