Bolus somatostatin but not octreotide reduces hepatic sinusoidal pressure by a NO-independent mechanism in chronic liver disease

Background: Evidence exists that somatostatin and octreotide might have dif ferent effects on hepatic haemodynamics. Aim: The investigation of the effects of somatostatin and its octapeptide a nalogue, octreotide, on sinusoidal pressure measured by the wedged hepatic venous pressure in patients with cirrhosis or chronic hepatitis and the cor relation with the levels of hepatic vein NO. Methods: Patients were randomly assigned to receive an injection of either 250 mug somatostatin (n=14: cirrhosis six, chronic hepatitis eight) or an i njection of 125 mug octreotide (n=19: cirrhosis nine, chronic hepatitis 10) during hepatic vein catheterization. Baseline wedged hepatic venous pressu re was measured, followed by measurements at 2, 5, 10 and 15 min after the injection of the drug. Nitrites/nitrates of the hepatic vein were measured before the injection and after 15 min. Results: Both agents showed a similar qualitative but a different quantitat ive haemodynamic profile. No change in the wedged hepatic venous pressure w as observed during the first 2 min after the injection of both drugs. This was followed by a decrease: 18% at 5 min (N.S.), 23% at 10 min (P < 0.01) a nd 24% at 15 min (P < 0.01) for somatostatin. Octreotide induced a relative ly smaller decrease in the wedged hepatic venous pressure: 8% at 5 min (N.S .), 20% at 10 min (P < 0.01) and 16% at 15 min (N.S.). Further analysis of the sub-groups of cirrhotic and chronic hepatitis patients revealed a diffe rent effect. In the sub-group of cirrhotic patients, somatostatin caused a maximum decrease of 34% at 15 min post-injection (P < 0.01), but octreotide failed to produce a significant change on the wedged hepatic venous pressu re. In contrast, no change was observed in chronic hepatitis patients with either drug. No change in the hepatic vein concentration of NO after treatm ent was observed with either somatostatin or octreotide. Moreover, no corre lation of the levels of NO with the wedged hepatic venous pressure values w as found. Conclusions: This study shows that somatostatin is more effective than octr eotide in acutely reducing the wedged hepatic venous pressure after bolus i njection and the observed change is probably mediated by a NO-independent m echanism.