Reduced portosystemic hemodynamic responsiveness after orthostasis in patients with cirrhosis.

We studied portosystemic hemodynamic responsiveness after 1 min orthostasis in nine patients with cirrhosis and nine age-matched normal subjects. Orthostasis increased diastolic arterial pressure, which is a close indicator of arterial tone, in normal subjects (+17%, P < 0.01). In contrast, no significant change in diastolic arterial pressure was observed in patients with cirrhosis (-3%, NS). The increase in heart rate was less in patients with cirrhosis than in normal subjects (+15% vs +28%, P < 0.05). Orthostasis also decreased portal blood flow, which was assessed by an echo-Doppler flowmetry, in normal subjects (-27%, P < 0.01), but in patients with cirrhosis it was not modified (-3%, NS). Plasma noradrenaline concentration showed similar increase in both groups (normal vs cirrhosis; +61% vs +55%, NS). Although the change in plasma noradrenaline concentration was related with that in diastolic arterial pressure (r = 0.71, P < 0.05) and inversely with that in portal blood flow (r = -0.69, P < 0.05) in normal subjects, no such significant correlation was found in patients with cirrhosis. We conclude that (1) a reduced hemodynamic responsiveness to sympathetic stimulation exists on both systemic and portohepatic vascular beds and (2) such a blunted baroreflex function is probably located at the receptor or effector level in patients with cirrhosis.