Irma Rossi

Continuous prazosin administration in cirrhotic patients: Effects on portal hemodynamics and on liver and renal function☆☆☆

BACKGROUND & AIMS Hepatic vascular resistance is influenced by alpha-adrenergic tone. The aim of this study was to investigate the effects of continuous blockade of alpha-adrenoceptors with prazosin on hemodynamics, liver function, and renal function and whether the association of propranolol or furosemide enhances the portal pressure lowering effect of prazosin. METHODS Cirrhotic patients with portal hypertension were studied at baseline and after a 3-month course of prazosin (n = 18) or placebo (n = 10). RESULTS No changes were observed in the placebo group. Prazosin decreased the hepatic venous pressure gradient (HVPG) while increasing hepatic blood flow. Liver function improved as shown by an increase in hepatic and intrinsic hepatic clearances of indocyanine green and galactose elimination capacity. A significant reduction in mean arterial pressure and systemic vascular resistance was associated with increases in plasma renin activity and aldosterone concentration and a decrease in glomerular filtration rate. The plasma volume increased significantly, and 6 patients developed edema. The association of propranolol (n = 8) but not furosemide (n = 7) to prazosin increased the reduction in HVPG and attenuated the increase in plasma renin activity. CONCLUSIONS In cirrhotic patients, continuous prazosin administration reduces portal pressure and improves liver perfusion and function but favors sodium and water retention. The association of propranolol enhances the decrease in portal pressure, suggesting a potential benefit from this combined therapy.

Octreotide prevents postprandial splanchnic hyperemia in patients with portal hypertension

An increase in splanchnic blood flow is a physiological response to food intake. In patients with cirrhosis whose hepatic vascular resistance is already high, this increase in flow leads to marked increases in portal pressure. This study investigates whether octreotide prevents the increases in hepatic flow and portal pressure that follow the ingestion of a meal in patients with cirrhosis. Twenty-two patients with cirrhosis and portal hypertension were randomized to receive a mixed liquid meal (520 kcal) plus a single subcutaneous injection of either placebo or octreotide (200 micrograms). In the placebo group the ingestion of a meal was followed by an increase in the hepatic venous pressure gradient (+ 19.4 +/- 4.3%, p < 0.01) and hepatic blood flow (+ 38.2 +/- 14.6%, p < 0.05) at 30 min. In contrast, in the octreotide group eating caused no significant change in the hepatic venous pressure gradient (-2.8 +/- 3.6%, NS), while hepatic flow was decreased (-6.08 +/- 5.4%, p < 0.05). Octreotide blunted the postprandial increase in serum insulin and glucagon levels observed in the placebo group. In conclusion, in patients with cirrhosis and portal hypertension, octreotide prevents the postprandial increase in hepatic blood flow, and consequently also in portal pressure. These findings suggest that this drug could play a role in the long-term management of portal hypertension.

Factors mediating the hemodynamic effects of tumor necrosis factor-α in portal hypertensive rats

Nitric oxide, prostacyclin, and glucagon have been implicated in promoting the hyperdynamic circulatory state of portal hypertension. Recent evidence also indicates that increased tumor necrosis factor-α (TNF-α) production is involved in the pathogenesis of this hemodynamic abnormality. This study was aimed at investigating in rats with portal vein stenosis (PVS) the effects on splanchnic hemodynamics of blocking circulating TNF-α and the factors mediating the vascular action of this cytokine in this setting. Anti-TNF-α polyclonal antibodies or placebo was injected into rats ( n = 96) before and 4 days after PVS (short-term inhibition) and at 24 h and 4, 7, 10 days after PVS (long-term inhibition). Short-term TNF-α inhibition reduced portal venous inflow and cardiac index and increased splanchnic and systemic resistance. Portal pressure was unchanged, but portal-systemic shunting was decreased. After long-term TNF-α inhibition, portal venous inflow and portal pressure were unchanged, but arterial pressure and systemic resistance rose significantly. Anti-TNF-α PVS rats exhibited lower increments of systemic resistance after N ω-nitro-l-arginine methyl ester and indomethacin administration and lower serum levels of TNF-α, nitrates-nitrites, and 6-keto-PGF1α, both over the short and the long term. Serum glucagon levels rose after long-term inhibition. In conclusion, the specific role played by TNF-α in the development of the hyperdynamic state of portal hypertension appears to be mainly mediated through an increased release of nitric oxide and prostacyclin. Maintenance of the splanchnic hyperemia after long-term TNF-α inhibition could be due to a compensatory release of glucagon.

Oral administration of clonidine in patients with alcoholic cirrhosis

The effects of long-term oral clonidine treatment on hepatic and systemic hemodynamics and on quantitative liver function tests were investigated in 15 patients with alcoholic cirrhosis. Clonidine was administered at a mean dose of 0.33 +/- 0.1 mg/day (mean +/- SD) for a mean period of 64 +/- 10 days. Oral clonidine induced a significant reduction in the hepatic venous pressure gradient from 18.8 +/- 3.0 mm Hg to 15.9 +/- 3.4 mm Hg (P less than 0.001), which was the result of an increase in the free hepatic venous pressure from 5.1 +/- 4.2 mm Hg to 8.7 +/- 3.8 mm Hg (P less than 0.05). In 10 of the 15 patients (67%), the reduction in the hepatic venous pressure gradient was greater than 10% of baseline values. Hepatic blood flow did not change significantly after clonidine treatment. Additionally, treatment with clonidine decreased mean arterial pressure by 15.5% +/- 6% (P less than 0.001), heart rate by 17.7% +/- 7% (P less than 0.001), and cardiac output by 14.6% +/- 7% (P less than 0.001). However, systemic vascular resistance did not change significantly. There were no adverse effects on liver function, as shown by the nonsignificant changes in galactose-elimination capacity (149 +/- 59 vs. 170 +/- 58 mg/min), hepatic clearance of indocyanine green (0.19 +/- 0.10 vs. 0.17 +/- 0.07 L/min), and hepatic intrinsic clearance of indocyanine green (0.23 +/- 0.14 vs. 0.21 +/- 0.1 L/min) before and after clonidine treatment, respectively. In none of the patients was the drug withdrawn because of side effects, although 12 subjects complained of dry mouths. This study suggests that in patients with alcoholic cirrhosis, long-term oral clonidine administration achieves a reduction in the hepatic venous pressure gradient without adverse effects on hepatic blood flow and liver function.

Effect of colistin on reduction of biliary flow induced by endotoxin ofE. coli

In order to evaluate whether an antiendotoxin agent can inhibit the action of endotoxin ofEscherichia coli on biliary flow, we used 18 models of isolated perfused pig liver divided into four groups: (A) five perfused livers (control), (B) five perfused livers with 2 mg/100 ml of endotoxin added, (C) five perfused livers with 2 mg/100 ml of endotoxin added and treated with 1,500,000 IU of colistin, and (D) three perfused livers with 1,500,000 IU of colistin with no endotoxin. The livers were isolated and perfused according to a technique previously described by our laboratory. The viability of the perfusions was controlled by means of the mitochondrial respiration test. Transaminase and LDH levels were measured in the perfusion circuit. A significant reduction of the biliary flow was found in the group with endotoxin ofEscherichia coli (P<0.002). There was no reduction of biliary flow after addition of 1,500,000 IU of colistin (P< 0.001). No significant changes were observed in the other parameters measured, and no increase of the bile flow was observed in the colistin group. From our results we conclude that colistin is an inhibitorin vitro of the diminished biliary flow induced by endotoxin ofEscherichia coli.