Beta-blockers to prevent esophageal varices--an unfulfilled promise

Comparison of balloon vs. straight catheter for the measurement of portal hypertension

BACKGROUND

The hepatic venous pressure gradient (HVPG) is used as an estimation of portal pressure (PP) in the management of patients with cirrhosis. Two methods are available using either a straight or a balloon catheter, but have never been compared head-to-head.

AIM

To compare the two methods of determining HVPG, straight and balloon catheter, regarding reproducibility and reliability.

METHODS

In 47 patients with liver cirrhosis, HVPG was assessed using both catheters in sequence. In another 29 patients, the wedged hepatic venous pressure (WHVP) determined either with straight or balloon catheter was correlated with a direct measurement of PP. Variation coefficient and intraclass correlation coefficient were calculated.

RESULTS

Variation coefficients for balloon catheter were 0.07 (HVPG), 0.02 (WHVP) and 0.06 [free hepatic venous pressure (FHVP)]. Variation coefficients for straight catheter were 0.17 (HVPG), 0.06 (WHVP) and 0.07 (FHVP), demonstrating a significantly wider variation of the HVPG and WHVP measurements (P < 0.001). Comparison of WHVP with PP revealed a correlation coefficient of 0.72 (P = 0.004) using balloon catheter and 0.58 (P = 0.011) using straight catheter.

CONCLUSIONS

Measurements with the balloon catheter currently represent the most reliable and reproducible method to assess HVPG. The results are of particular clinical relevance if repeated measurements are required for therapeutic adjustments.

Defective endothelial nitric oxide synthase signaling is mediated by rho-kinase activation in rats with secondary biliary cirrhosis

In liver cirrhosis, down-regulation of endothelial nitric oxide synthase (eNOS) has been implicated as a cause of increased intrahepatic resistance. We investigated whether Rho-kinase activation is one of the molecular mechanisms involved in defective eNOS signaling in secondary biliary cirrhosis. Liver cirrhosis was induced by bile duct ligation (BDL). We measured mean arterial pressure (MAP), portal venous pressure (PVP), and hepatic tissue blood flow (HTBF) during intravenous infusion of saline (control), 0.3, 1, or 2 mg/kg/hour fasudil for 60 minutes. In BDL rats, 1 and 2 mg/kg/hour fasudil significantly reduced PVP by 20% compared with controls but had no effect on HTBF. MAP was significantly reduced in response to 2 mg/kg/hour fasudil. In the livers of BDL rats, 1 and 2 mg/kg/hour fasudil significantly suppressed Rho-kinase activity and significantly increased eNOS phosphorylation, compared with controls. Fasudil significantly reduced the binding of serine/threonine Akt/PKB (Akt) to Rho-kinase and increased the binding of Akt to eNOS. These results show in secondary biliary cirrhosis that (1) Rho-kinase activation with resultant eNOS down-regulation is substantially involved in the pathogenesis of portal hypertension and (2) Rho-kinase might interact with Akt and subsequently inhibit the binding of Akt to eNOS.

Hepatic venous pressure gradient and outcomes in cirrhosis

End-stage liver disease is characterized by the development of complications related to portal hypertension. Hepatic venous pressure gradient (HVPG), as an estimation of portal pressure, has been associated to the development of these complications. Most of the data that has been published in this regard is in the context of the development of varices and variceal bleeding. However, HVPG has also been associated to the development or the outcome of other complications of portal hypertension, hepatocellular carcinoma, liver transplantation, and survival. This review analyses the published data regarding the association between the HVPG and the different possible outcomes in cirrhosis.

Chronic oral anticoagulant therapy for extrahepatic visceral thrombosis is safe

BACKGROUND

Patients with hypercoagulability may thrombose visceral veins with resultant portal hypertension, esophagogastric varices, and hemorrhage. The role of chronic oral anticoagulant therapy in such patients is unclear. On the one hand, such patients are prone to significant hemorrhage and thus anticoagulant therapy may seem contraindicated. On the other hand, because the causal pathophysiology is typically hypercoagulability, it would seem rational to treat these patients with chronic anticoagulant therapy in order to both prevent other visceral and systemic thromboses and perhaps, over time, reduce the degree of portal hypertension. Experience and poor prognosis associated with the more common portal hypertension due to hepatic cirrhosis may bias judgment.

METHODS

We retrospectively reviewed the course of chronic oral anticoagulant therapy regarding both the safety and effectiveness using our long-term follow-up of a cohort of seven patients with visceral thrombosis resulting in extrahepatic non-cirrhotic portal hypertension.

RESULTS

Seven consecutive patients encountered over the past 19 years were observed for 78 patient-years, the first 14 patient-years prior to anticoagulant therapy and the latter 64 patient-years on oral anticoagulant therapy. No patients rethrombosed either visceral or systemic vessels while on oral anticoagulant therapy. There were no fatal or serious hemorrhagic events on oral anticoagulant therapy; in fact, upper gastrointestinal bleeding decreased from 1.2 to 0.2 bleeds/year. The endoscopic grade of esophageal varices decreased in four of five patients who underwent serial endoscopy, and platelet counts increased in all seven patients.

CONCLUSIONS

Chronic oral anticoagulant therapy is safe and not associated with an increase in upper gastrointestinal bleeding in such patients. Additionally, and by inference, perhaps in conjunction with the natural history of portal hypertension, such therapy is possibly effective in reducing portal hypertension in patients with hypercoagulability-induced extrahepatic portal hypertension.

Value of the hepatic venous pressure gradient to monitor drug therapy for portal hypertension: a meta-analysis

OBJECTIVES

The use of the hepatic venous pressure gradient (HVPG) to assess the efficacy of the pharmacological treatment of portal hypertension in cirrhosis is controversial. Our aim was to establish whether target HVPG reduction predicts variceal bleeding in cirrhotic patients receiving variceal bleeding prophylaxis.

METHODS

Data sources were MEDLINE, EMBASE, Cochrane Controlled Trials Register, citation lists, and abstracts (most recent search March 2006). Cohorts of patients on drug therapy from randomized and nonrandomized studies correlating variceal bleeding and HVPG change were used. Heterogeneity was explored by metaregression analysis.

RESULTS

Ten studies totaling 595 patients undergoing two HVPG measurements were identified. The RR of bleeding was lower in patients achieving an overall (HVPG <or=12 mmHg or decrease >or=20%) (0.27, 95% CI 0.14-0.52), complete (HVPG <or=12 mmHg) (0.48, CI 0.28-0.81), or partial (HVPG decrease >or=20%) (0.41, CI 0.20-0.81) response, with significant heterogeneity. Regression analysis identified the interval between the HVPG measurements significantly associated with the RR of bleeding. Heterogeneity was no longer significant after exclusion of an outlier trial, which showed the longest interval to HVPG remeasurement and the lowest quality score. Even considering nonvaluable patients because of bleeding as HVPG responders, the RR of bleeding was lower in overall responders than in nonresponders (0.66, CI 0.51-0.86). Overall response was associated with lower liver-related mortality (RR 0.58, CI 0.37-0.91).

CONCLUSIONS

Current evidence supports the validity of HVPG end points to monitor drug therapy efficacy for variceal bleeding prophylaxis. HVPG monitoring also provides valuable prognostic information.

Portal hypertension

PURPOSE OF REVIEW

Significant advances in the pathophysiology, diagnosis and management of the complications of portal hypertension that have occurred in the last year are reported.

RECENT FINDINGS

The specific areas reviewed are those that refer to experimental studies aimed at modifying the factors that lead to portal hypertension (increased intrahepatic vascular resistance and splanchnic vasodilatation) and recent advances in the diagnosis and management of the complications of portal hypertension. The specific complications reviewed in this paper are varices and variceal bleeding (primary prophylaxis, treatment of the acute episode and secondary prophylaxis), ascites and hepatorenal syndrome, spontaneous bacterial peritonitis and hepatic encephalopathy, as well as recent studies of predictors of death in cirrhosis.

SUMMARY

Important studies, mostly prospective, regarding the management of the complications of portal hypertension are reviewed, including a trial of beta-blockers in the prevention of varices, a randomized trial of endoscopic variceal ligation plus nadolol in preventing recurrent variceal bleeding and several meta-analyses on trials comparing large-volume paracentesis with transjugular intrahepatic portosystemic shunt in the management of refractory ascites.

Beta-blockers to prevent gastroesophageal varices in patients with cirrhosis

BACKGROUND

Nonselective beta-adrenergic blockers decrease portal pressure and prevent variceal hemorrhage. Their effectiveness in preventing varices is unknown.

METHODS

We randomly assigned 213 patients with cirrhosis and portal hypertension (minimal hepatic venous pressure gradient [HVPG] of 6 mm Hg) to receive timolol, a nonselective beta-blocker (108 patients), or placebo (105 patients). The primary end point was the development of gastroesophageal varices or variceal hemorrhage. Endoscopy and HVPG measurements were repeated yearly.

RESULTS

During a median follow-up of 54.9 months, the rate of the primary end point did not differ significantly between the timolol group and the placebo group (39 percent and 40 percent, respectively; P=0.89), nor were there significant differences in the rates of ascites, encephalopathy, liver transplantation, or death. Serious adverse events were more common among patients in the timolol group than among those in the placebo group (18 percent vs. 6 percent, P=0.006). Varices developed less frequently among patients with a baseline HVPG of less than 10 mm Hg and among those in whom the HVPG decreased by more than 10 percent at one year and more frequently among those in whom the HVPG increased by more than 10 percent at one year.

CONCLUSIONS

Nonselective beta-blockers are ineffective in preventing varices in unselected patients with cirrhosis and portal hypertension and are associated with an increased number of adverse events. (ClinicalTrials.gov number, NCT00006398.)