Effects of alpha-adrenergic stimulation and beta-adrenergic blockade on azygos blood flow and splanchnic haemodynamics in patients with cirrhosis.
The effects of beta-blockade with propranolol and of alpha-adrenergic stimulation with methoxamine, a powerful alpha-agonist, on azygos blood flow and on systemic and hepatic haemodynamics were investigated in 26 cirrhotic patients with portal hypertension. Beta-adrenergic blockade with propranolol (n = 12), evidenced by a significant reduction of heart rate (-17 +/- 1%, P less than 0.001) and cardiac index (-17 +/- 2%, P less than 0.001), caused a mild but significant decrease of hepatic venous pressure gradient (-10 +/- 2%, P less than 0.05) and a marked fall of azygos venous blood flow (-31 +/- 5%, P less than 0.05). Alpha-adrenergic stimulation with methoxamine (n = 14), manifested by a significant increase of mean arterial pressure (19 +/- 2%, P less than 0.001), mimicked the effects of propranolol on hepatic venous pressure gradient (-10 +/- 4%, P less than 0.05) and cardiac index (-11 +/- 2%, P less than 0.001). However, azygos blood flow was not significantly reduced by methoxamine (0.7 +/- 0.1 vs 0.6 +/- 0.1 l/min). On the contrary, hepatic blood flow was significantly reduced by methoxamine (-19 +/- 4%, P less than 0.01) but not by propranolol (-7 +/- 7%, ns). Similarly, in 8 patients who received methoxamine after being beta-blocked by propranolol, azygos blood flow, that was markedly reduced by beta-blockade, did not experience a further reduction but increased slightly by alpha-adrenergic stimulation, while hepatic blood flow, that was not reduced by propranolol, decreased significantly during the subsequent methoxamine infusion.(ABSTRACT TRUNCATED AT 250 WORDS)
D001401:Azygos Vein / Q000503:physiopathology; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D006975:Hypertension, Portal / Q000150:complications / Q000503:physiopathology; D008102:Liver Circulation / Q000187:drug effects; D008103:Liver Cirrhosis / Q000150:complications / Q000503:physiopathology*; D008297:Male; D008729:Methoxamine / Q000494:pharmacology*; D008875:Middle Aged; D011433:Propranolol / Q000494:pharmacology*; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000502:physiology; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000502:physiology; D013152:Splanchnic Circulation / Q000187:drug effects
D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D011433:Propranolol; D008729:Methoxamine