Factors mediating the hemodynamic effects of tumor necrosis factor-alpha in portal hypertensive rats.
(1/1000)
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-alpha (TNF-alpha) 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-alpha and the factors mediating the vascular action of this cytokine in this setting. Anti-TNF-alpha 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-alpha 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-alpha inhibition, portal venous inflow and portal pressure were unchanged, but arterial pressure and systemic resistance rose significantly. Anti-TNF-alpha PVS rats exhibited lower increments of systemic resistance after Nomega-nitro-L-arginine methyl ester and indomethacin administration and lower serum levels of TNF-alpha, nitrates-nitrites, and 6-keto-PGF1alpha, both over the short and the long term. Serum glucagon levels rose after long-term inhibition. In conclusion, the specific role played by TNF-alpha 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-alpha inhibition could be due to a compensatory release of glucagon. (+info)
Comparison of endoscopic ligation and propranolol for the primary prevention of variceal bleeding.
(2/1000)
BACKGROUND AND METHODS: We compared propranolol therapy and endoscopic ligation for the primary prevention of bleeding from esophageal varices. This prospective, controlled trial included consecutive eligible patients who had large varices (>5 mm in diameter) that were at high risk for bleeding. The patients were assigned to either propranolol therapy, at a dose sufficient to decrease the base-line heart rate by 25 percent, or variceal ligation, to be performed weekly until the varices were obliterated or so reduced in size that it was not possible to continue treatment. RESULTS: Of the 89 patients, 82 of whom had cirrhosis of the liver, 44 received propranolol and 45 underwent variceal ligation. The mean (+/-SD) duration of follow-up in each group was 14+/-9 and 13+/-10 months, respectively. The mean time required to achieve an adequate reduction in the heart rate was 2.5+/-1.7 days; the mean number of sessions needed to complete variceal ligation was 3.2+/-1.1. After 18 months, the actuarial probability of bleeding was 43 percent in the propranolol group and 15 percent in the ligation group (P=0.04). Twelve patients in the propranolol group and four in the ligation group had bleeding. Three of the four in the ligation group had bleeding before their varices had been obliterated. Nine patients in the ligation group had recurrent varices, a mean of 3.7 months after the initial treatment. Five patients in each group died; bleeding from the varices was the cause of death of four patients in the propranolol group and of three in the ligation group. There were no serious complications of variceal ligation; in the propranolol group, treatment was stopped in two patients because of side effects. CONCLUSIONS: In patients with high-risk esophageal varices, endoscopic ligation of the varices is safe and more effective than propranolol for the primary prevention of variceal bleeding. (+info)
NO overproduction by eNOS precedes hyperdynamic splanchnic circulation in portal hypertensive rats.
(3/1000)
Chronic high blood flow and the hyperdynamic circulatory syndrome in portal hypertension are associated with endothelial constitutive nitric oxide (NO) synthase (eNOS) upregulation and increased NO release. In portal vein-ligated (PVL) rats the splanchnic circulation is not yet hyperdynamic on day 3 postoperatively. In vitro perfused superior mesenteric arteries (SMAs) of day 3 PVL and sham rats were challenged with increasing flow rates or the alpha-adrenoreceptor agonist methoxamine (30 and 100 microM) before and after incubation with the NO inhibitor, Nomega-nitro-L-arginine (L-NNA, 10(-4) M). Perfusate NO metabolite (NOx) concentrations were measured by chemiluminescence. PVL rats expressed a significant hyporesponsiveness to increases in flow rate or methoxamine that was overcome by incubation with L-NNA. The PVL vasculature showed significantly higher slopes of NOx production vs. flow-induced shear stress, higher increases in perfusate NOx concentration in response to methoxamine, and higher eNOS protein levels (Western blot) compared with sham rats. In conclusion, eNOS-upregulation and increased NO release by the SMA endothelium occur before the development of the hyperdynamic splanchnic circulation, suggesting a primary role of NO in the pathogenesis of arterial vasodilatation. (+info)
Gastric antral vascular ectasia in cirrhotic patients: absence of relation with portal hypertension.
(4/1000)
BACKGROUND: Portal hypertensive gastropathy and gastric antral vascular ectasia (GAVE) are increasingly recognised as separate entities. The pathogenic role of portal hypertension for the development of GAVE is still controversial. AIMS: To evaluate the effects of portal decompression on chronic bleeding related to GAVE in cirrhotic patients. METHODS: Eight patients with cirrhosis and chronic blood loss related to GAVE were included. GAVE was defined endoscopically and histologically. RESULTS: All patients had severe portal hypertension (mean portocaval gradient (PCG) 26 mm Hg) and chronic low grade bleeding. Seven patients underwent transjugular intrahepatic portosystemic shunt (TIPS) and one had an end to side portacaval shunt. Rebleeding occurred in seven patients. In these, TIPS was found to be occluded after 15 days in one patient; in the other six, the shunt was patent and the PCG was below 12 mm Hg in five. In the responder, PCG was 16 mm Hg. Antrectomy was performed in four non-responders; surgery was uneventful, and they did not rebleed after surgery, but two died 11 and 30 days postoperatively from multiorgan failure. In one patient, TIPS did not control GAVE related bleeding despite a notable decrease in PCG. This patient underwent liver transplantation 14 months after TIPS; two months after transplantation, bleeding had stopped and the endoscopic appearance of the antrum had normalised. CONCLUSIONS: Results suggest that GAVE is not directly related to portal hypertension, but is influenced by the presence of liver dysfunction. Antrectomy is a therapeutic option when chronic bleeding becomes a significant problem but carries a risk of postoperative mortality. (+info)
Splanchnic and systemic haemodynamic response to volume changes in patients with cirrhosis and portal hypertension.
(5/1000)
We investigated the haemodynamic response to volume depletion and subsequent repletion in patients with cirrhosis and portal hypertension. Twelve patients with compensated cirrhosis and portal hypertension were included in the study. The haemodynamic changes occurring after removal of approx. 15% of the blood volume, and subsequently after isovolume repletion with colloid, were assessed. Baseline haemodynamic measurements showed increased cardiac output and a systemic vascular resistance at the lower limit of normal. The hepatic venous pressure gradient (HVPG) was increased, at 18 mmHg. After depletion, arterial pressure, cardiac output and all right-heart-sided pressures decreased, and systemic vascular resistance increased. HVPG decreased to 16.0 mmHg. All the above changes were statistically significant. After blood volume restitution, the haemodynamic values returned to baseline. In particular, an increase in HVPG was shown in four out of the twelve patients (two with ascites and two without), which was small in three of them. However, HVPG remained the same as or lower than the baseline in the other eight patients. Patients with cirrhosis and portal hypertension exhibit an abnormal haemodynamic response to blood volume depletion. After volume repletion, no increase in the portal pressure was noted in this group of patients as a whole, although four out of the twelve patients did show an increase, possibly due to extensive collateral circulation. (+info)
Cirrhosis of the liver in long-term marrow transplant survivors.
(6/1000)
Patients who survive hematopoietic cell transplantation (HCT) have multiple risk factors for chronic liver disease, including hepatitis virus infection, iron overload, and chronic graft-versus-host disease (GVHD). We studied 3,721 patients who had survived 1 or more years after HCT at a single center and identified patients with histologic or clinical evidence of cirrhosis. Risk factors for the development of cirrhosis were evaluated and compared with a group of matched control subjects. Cirrhosis was identified in 31 of 3,721 patients surviving 1 or more years after HCT, 23 of 1,850 patients surviving 5 or more years, and in 19 of 860 patients surviving 10 or more years. Cumulative incidence after 10 years was estimated to be 0.6% and after 20 years was 3.8%. The median time from HCT to the diagnosis of cirrhosis was 10.1 years (range, 1.2 to 24.9 years). Twenty-three patients presented with complications of portal hypertension, and 1 presented with hepatocellular carcinoma. Thirteen patients have died from complications of liver disease, and 2 died of other causes. Three patients have undergone orthotopic liver transplantation. Hepatitis C virus infection was present in 25 of 31 (81%) of patients with cirrhosis and in 14 of 31 (45%) of controls (P =.01). Cirrhosis was attibutable to hepatitis C infection in 15 of 16 patients presenting more than 10 years after HCT. There was no difference in the prevalence of acute or chronic GVHD, duration of posttransplant immunosuppression, or posttransplant marrow iron stores between cases and controls. Cirrhosis is an important late complication of hematopoietic cell transplantation and in most cases is due to chronic hepatitis C. Long-term survivors should be evaluated for the presence of abnormal liver function and hepatitis virus infection. (+info)
Current status of transjugular intrahepatic portosystemic shunts.
(7/1000)
The use of the transjugular intrahepatic portosystemic shunt (TIPS) has emerged as an important nonoperative modality for variceal bleeding, intractable ascites, and for selected cases of hepatic venous obstruction. We believe that TIPS should be viewed as a 'bridge' to liver transplantation and should be carried out only in experienced centres. The adverse haemodynamic changes on the cardiopulmonary system after TIPS should be borne in mind. Prospective trials to evaluate the role of TIPS versus sclerotherapy in variceal bleeding will be watched with interest. There is, however, an urgent need to improve long-term results of TIPS as stent thrombosis and stenosis occur frequently. We advocate routine surveillance to detect these problems at an early stage. (+info)
Do alterations in the rate of gastric emptying after injection sclerotherapy for oesophageal varices play any role in the development of portal hypertensive gastropathy?
(8/1000)
Bleeding from portal hypertensive gastropathy (PHG) has been estimated to account for up to 30% of all upper gastrointestinal haemorrhage in patients with cirrhosis and portal hypertension. Although portal hypertension seems to be an essential prerequisite, the precise mechanisms responsible for the development of PHG are unknown. The aim of this study was to examine the role of injection sclerotherapy of oesophageal varices in the development of PHG. Gastric emptying was studied using a radionuclide test meal with the emptying characteristics of a slow liquid in 57 patients with cirrhosis and/or portal hypertension (median age 53 yrs), of whom 34 had received injection sclerotherapy for their oesophageal varices and 20 normal healthy volunteers (median age 42 yrs). As vagal damage is associated with more rapid emptying of liquids, despite hold up of solids, this technique might be expected to demonstrate such damage if gastric emptying was accelerated. The results indicated that there was no difference in the rate of gastric emptying between normal healthy volunteers and portal hypertensive patients. However, patients who had received injection sclerotherapy emptied their stomachs faster than those who had not (p < 0.05). Furthermore, the speed of gastric emptying correlated directly with the number of injections (r = 0.41; p = 0.02) and the volume of sclerosant injected (r = 0.39; p = 0.03). These observations suggest that injection sclerotherapy for oesophageal varices results in disturbances of gastric emptying that may contribute to the pathogenesis of portal hypertensive gastropathy. (+info)