Propranolol plus isosorbide-5-mononitrate for portal hypertension in cirrhosis: long-term hemodynamic and renal effects

Association of non-selective β blockers with the development of renal dysfunction in liver cirrhosis: a systematic review and meta-analysis

BACKGROUND & AIMS

Non-selective β blockers (NSBBs) may negatively influence renal function through decreasing heart rate and cardiac output. This study aimed to systematically investigate their association.

METHODS

PubMed, EMBASE, and Cochrane library databases were searched to identify all relevant studies evaluating the association of NSBBs with renal dysfunction in cirrhotic patients. Unadjusted and adjusted data were separately extracted. Odds ratios (ORs) and hazard ratios (HRs) were pooled. Subgroup meta-analyses were performed according to the proportions of ascites and Child-Pugh class B/C and the mean model for end-stage liver disease (MELD) score. Quality of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation framework.

RESULTS

Fourteen studies were finally included. Based on unadjusted data, NSBBs significantly increased the risk of developing renal dysfunction (OR = 1.49; p = 0.03), and this association remained significant in subgroup analyses of studies where the proportions of ascites was >70% and Child-Pugh class B/C was 100%. Based on adjusted data with propensity score matching (adjusted OR = 0.61; p = 0.08) and multivariable regression modelling (adjusted HR = 0.86; p = 0.713), NSBBs did not increase the risk of developing renal dysfunction, and this association remained not significant in subgroup analyses of studies where the proportions of ascites was >70% and <70%, the proportion of Child-Pugh class B/C was <100%, and the mean MELD score was <15. The quality of evidence was very low for all meta-analyses.

CONCLUSIONS

NSBBs may not be associated with the development of renal dysfunction in liver cirrhosis. However, more evidence is required to clarify their association in specific populations.

Role of angiotensin II in liver fibrosis-induced portal hypertension and therapeutic implications

Angiotensin II (AT-II) is a peptide that plays an important role in the renin-angiotensin-aldosterone (RAA) system. Traditionally, the RAA system has been related with states of systemic hypertension and hypoperfusion as a counterbalance mechanism. Recently, AT-II has been studied for its properties in the process of fibrosis in several organs, especially in the liver. AT-II is capable to stimulate the activated hepatic stellate cells, which increase expression of profibrogenic molecules like tumor growth factor-beta, tissue inhibitor of metalloproteinase-1 and collagen I, among others. At the same time, AT-II is implied in the hemodynamic balance of cirrhosis and portal hypertension. Due to its profibrogenic and vasoactive properties, blockade of AT-II actions constitutes an important therapeutic target to inhibit fibrotic processes and reduction of risk of complications of portal hypertension as well. Some drugs like angiotensin-converting enzyme inhibitors or the angiotensin II receptor blockers have been studied as alternatives for the treatment of patients with cirrhosis with promising results. Nonetheless, additional research is required in order to consider these drugs as a part of the integral treatment of the patient with cirrhosis and portal hypertension.

Clinical trial: a randomized controlled study on prevention of variceal rebleeding comparing nadolol + ligation vs. hepatic venous pressure gradient-guided pharmacological therapy

BACKGROUND

Hepatic venous pressure gradient (HVPG) monitoring of therapy to prevent variceal rebleeding provides strong prognostic information. Treatment of nonresponders to beta-blockers +/- nitrates has not been clarified.

AIM

To assess the value of HVPG-guided therapy using nadolol + prazosin in nonresponders to nadolol + isosorbide-5-mononitrate (ISMN) compared with a control group treated with nadolol + ligation.

METHODS

Cirrhotic patients with variceal bleeding were randomized to HVPG-guided therapy (n = 30) or nadolol + ligation (n = 29). A Baseline haemodynamic study was performed and repeated within 1 month. In the guided-therapy group, nonresponders to nadolol + ISMN received nadolol and carefully titrated prazosin and had a third haemodynamic study.

RESULTS

Nadolol + prazosin decreased HVPG in nonresponders to nadolol + ISMN (P < 0.001). Finally, 74% of patients were responders in the guided-therapy group vs. 32% in the nadolol + ligation group (P < 0.01). The probability of rebleeding was lower in responders than in nonresponders in the guided therapy group (P < 0.01), but not in the nadolol + ligation group (P = 0.41). In all, 57% of nonresponders rebled in the guided-therapy group and 20% in the nadolol + ligation group (P = 0.05). The incidence of complications was similar.

CONCLUSIONS

In patients treated to prevent variceal rebleeding, the association of nadolol and prazosin effectively rescued nonresponders to nadolol and ISMN, improving the haemodynamic response observed in controls receiving nadolol and endoscopic variceal ligation. Our results also suggest that ligation may rescue nonresponders.

Effect of the nitric oxide donor V-PYRRO/NO on portal pressure and sinusoidal dynamics in normal and cirrhotic mice

Reduced sinusoidal endothelial nitric oxide (NO) production contributes to increased intrahepatic resistance and portal hypertension after liver injury. We hypothesized that V-PYRRO/NO, an NO donor prodrug metabolized "specifically" in the liver, would reduce portal venous pressure (PVP) without affecting the systemic vasculature. Liver injury was induced in male BALB/c mice by weekly CCl(4) gavage. PVP and mean arterial pressure were recorded during intravenous administration of V-PYRRO/NO. In vivo microscopy was used to monitor sinusoidal diameter and flow during drug administration. Mean PVP was increased in CCl(4)-treated mice compared with sham-treated mice. In dose-response experiments, the minimum dose of PYRRO/NO required to acutely lower PVP by 20%, the amount believed to yield a clinically meaningful outcome, was 200 nmol/kg. This dose decreased portal pressure in cirrhotic (23.4 +/- 2.0%, P < 0.001 vs. vehicle) and sham-treated (19.5 +/- 2.3%, P < 0.001 vs. vehicle) animals by a similar magnitude. This concentration also led to dilation of hepatic sinusoids and an increase in sinusoidal volumetric flow, consistent with a reduction of intrahepatic resistance. The effect of V-PYRRO/NO on mean arterial pressure was significant at all concentrations tested, including the lowest, 30 nmol/kg (P < 0.001 vs. vehicle for all doses). We conclude that V-PYRRO/NO had widespread vascular effects and, as such, is unlikely to be suitable for treatment of portal hypertension. As the potential of this or other similar compounds for treatment of portal hypertension is evaluated, effects on the systemic vasculature will also need to be considered.

Acute variceal bleeding: pharmacological treatment and primary/secondary prophylaxis

Variceal bleeding is one of the most severe complications of portal hypertension related to liver cirrhosis. Primary prophylaxis is considered mandatory in patients with cirrhosis and high-risk oesophageal varices, and once varices have bled, every effort should be made to arrest the haemorrhage and prevent further bleeding episodes. In acute variceal bleeding, vasoactive drugs that lower portal pressure should be started even before endoscopy, and should be maintained for up to 5 days. The choice of vasoactive drug should be made according to local resources. Terlipressin, somatostatin and octreotide can be used; vasopressin plus transdermal nitroglycerin may be used if no other drug is available. In variceal bleeding, antibiotic therapy is also mandatory. In primary and secondary prophylaxis, beta-blockers are the mainstay of therapy. In secondary prophylaxis (but not in primary prophylaxis) these drugs can be combined with organic nitrates.

Effect of vardenafil, an inhibitor of phosphodiesterase-5, on portal haemodynamics in normal and cirrhotic liver -- results of a pilot study

BACKGROUND

Dysregulation of the cyclic guanosine 3',5' monophosphate-nitric oxide system is in part responsible for portal hypertension in cirrhosis.

AIM

To test the effects of inhibitors of phosphodiesterase-5 on portal haemodynamics.

METHODS

To 18 healthy subjects and 18 patients with Child A liver cirrhosis, 10 mg of vardenafil, an inhibitor of phosphodiesterase-5, were administered orally. Doppler sonographic measurements of hepatic and splanchnic blood flow, systemic blood pressure and heart rate were recorded before, 1 h after, and 48 h after the application. Vardenafil plasma levels were determined after 1 h. In five patients, invasive registration of free and wedged hepatic vein pressure was performed.

RESULTS

Portal venous flow increased in patients from 0.82 +/- 0.30 L/min (mean +/- s.d.) by 26% (CI: 16-37%, P = 0.0004) and in healthy subjects from 0.75 +/- 0.20 L/min (mean +/- s.d.) by 19% (CI: 9-28%; P = 0.0010). Celiac and hepatic artery resistivity indices rose significantly. Systemic blood pressure decreased slightly in patients. The wedged hepatic venous pressure gradient decreased in four of five patients with liver cirrhosis. Vardenafil plasma levels were higher in patients (14 +/- 10 microg/L) than in healthy subjects (9 +/- 6 microg/L; n.s.).

CONCLUSIONS

Inhibition of phosphodiesterase-5 increases portal flow and lowers portal pressure by a decrease in sinusoidal resistance and may be a novel therapeutic strategy for portal hypertension.

Increased hepatic resistance: a new target in the pharmacologic therapy of portal hypertension

Increased resistance to portal blood flow is the primary factor in the pathophysiology of portal hypertension, and is mainly determined by the morphologic changes occurring in chronic liver diseases. This is aggravated by an increased hepatic vascular tone, which results from an insufficient hepatic bioavailability of nitric oxide (NO) and an increased production of circulating and local vasoconstrictors (angiotensin, endothelin, cysteinyl-leukotrienes, and thromboxane, among others). This dynamic and reversible component provides the rationale for the use of therapies aimed at decreasing portal pressure by reducing the vascular tone. Among them, systemic and liver-selective NO donors, statins, and gene therapy with adenovirus encoding NO synthases have been used to increase NO availability with promising results. Other attempts have been the blockade of the effect of vasoconstrictors, using anti alpha-adrenergic agents and renin-angiotensin system blockers. Some of these pharmacologic approaches have already been incorporated into clinical practice while others are still under investigation.

Variceal bleeding: pharmacological therapy

The complications of portal hypertension are totally prevented if hepatic venous pressure gradient is decreased below 12 mm Hg. Besides, if this target is not achieved, a 20% decrease in portal pressure from baseline levels offers an almost total protection from variceal bleeding. This sets the rationale for drug therapy to reduce portal pressure in portal hypertension. Pharmacological therapy to decrease portal pressure includes vasoconstrictors to decrease portal blood inflow, vasodilators to decrease hepatic resistance, and combination therapy. Oral agents, such as beta-adrenergic blockers and organic nitrates, are used for long-term prevention of variceal bleeding, while parenteral agents, such as somatostatin (and analogues) and terlipressin, are used for the treatment of acute variceal bleeding.

The role of vasoactive drugs in the treatment of oesophageal varices

Oesophageal varices are among the most important clinical consequences of portal hypertension. Recent progress in the knowledge of the pathophysiology of portal hypertension has led to the concept that it results from the increase of sinusoidal resistance and the increase in portal blood inflow consequent to splanchnic vasodilatation. Vasoactive drugs have therefore been evaluated, aiming to restore the imbalance between the increased intrahepatic and the decreased splanchnic vascular resistance. A large number of randomised, controlled trials have shown that vasoactive drugs in single or combination therapy, significantly reduce the risk of the first bleeding and rebleeding from oesophageal varices. Vasoactive drugs are also effective and safe in controlling acute variceal bleeding. Because of their high clinical efficacy, safety, ease of use and low cost, vasoactive drugs should be considered the first choice treatment for oesophageal varices.

NCX-1000, a nitric oxide-releasing derivative of ursodeoxycholic acid, ameliorates portal hypertension and lowers norepinephrine-induced intrahepatic resistance in the isolated and perfused rat liver

BACKGROUND/AIMS

We studied whether acute administration of NCX-1000, a nitric oxide (NO)-releasing derivative of ursodeoxycholic acid (UDCA), to animals with established liver cirrhosis decreases intrahepatic resistance and modulates hepatic vascular hypereactivity to norepinephrine (NE).

METHODS

Four-week bile duct ligated (BDL) cirrhotic and control, sham-operated, rats were treated orally with 28 mg/kg per day NCX-1000 or 15 mg/kg per day UDCA for 5 days. Isolated normal and cirrhotic livers were perfused with NE, from 10 nM to 30 microM, in a recirculating system.

RESULTS

NCX-1000 administration to BDL cirrhotic rats decreased portal pressure (P<0.01) without affecting mean arterial pressure and heart rate. In the isolated perfused liver system, administration of NE resulted in a dose-dependent increase of intrahepatic resistance. Vasoconstriction caused by 30 microM NE was reduced by 60% in animals treated with NCX-1000 (P<0.001), while UDCA was uneffective. The same portal pressure lowering effect was documented in cirrhotic and sham operated rats. Administration of NCX-1000 to BDL and sham operated rats resulted in a similar increase of nitrite/nitrate and cGMP concentrations in the liver.

CONCLUSIONS

By selectively delivering NO to the liver, NCX-1000 increases cGMP concentrations and effectively counteracts the effect of endogenous vasoconstrictors on the hepatic vascular tone.

Portal pressure response to losartan compared with propranolol in patients with cirrhosis

OBJECTIVES

Losartan, an angiotensin II receptor blocker, has portal hypotensive effects. This study evaluates the effect of losartan on portal pressure after 14 days and compares it with that of propranolol.

METHODS

A total of 39 individuals with cirrhosis were randomized into two groups of 19 and 20 patients each and were treated with losartan and propranolol, respectively. Hepatic venous pressure gradient was measured at baseline and on day 14 of therapy. Responders to therapy had hepatic venous pressure gradient reduction of >/=20% of baseline value.

RESULTS

With losartan, 15 of 19 (78.94%) patients were responders and with propranolol, nine of 20 (45%) patients were responders (p < 0.05). Although the hepatic venous pressure gradient reduction (i.e., percentage from baseline) with losartan (26.74 +/- 21.7%) was higher than with propranolol (14.52 +/- 32%), the difference was not significant. The reduction in hepatic venous pressure gradient with losartan was contributed mainly by a significant drop of wedge hepatic venous pressure from 32.42 +/- 6.61 mm of Hg to 28.31 +/- 5.09 mm of Hg (p < 0.05) compared to that with propranolol, which was from 34.55 +/- 5.41 mm of Hg to 32.75 +/- 8.13 mm of Hg (p > 0.05). Responders among alcohol-abusing patients were significantly higher with losartan (81.8%) compared to those on propranolol (27.2%; p < 0.05). In the losartan group, all seven nonascitic cirrhotic individuals, as compared with two of five in the propranolol group, responded to the drugs. During the study, no significant side effects were observed in either group (who were not receiving diuretics) or in follow-up with diuretics.

CONCLUSIONS

Losartan is as effective as propranolol in reducing portal pressure in cirrhotic patients who are not receiving diuretics. Losartan is also superior to propranolol for achieving target level hepatic venous gradient for prevention of variceal bleeding in nonascitic and alcohol-abusing cirrhotic patients.

Propranolol plus placebo versus propranolol plus isosorbide-5-mononitrate in the prevention of a first variceal bleed: a double-blind RCT

Nonselective beta-blockers are very effective in preventing first variceal bleeding in patients with cirrhosis. Treatment with isosorbide-5-mononitrate (IS-MN) plus propranolol achieves a greater reduction in portal pressure than propranolol alone. The present multicenter, prospective, double-blind, randomized, controlled trial evaluated whether combined drug therapy could be more effective than propranolol alone in preventing variceal bleeding. A total of 349 consecutive cirrhotic patients with gastroesophageal varices were randomized to receive propranolol + placebo (n = 174) or propranolol + IS-MN (n = 175). There were no significant differences in the 1- and 2-year actuarial probability of variceal bleeding between the 2 groups (propranolol + placebo, 8.3% and 10.6%; propranolol + IS-MN, 5% and 12.5%). The only independent predictor of variceal bleeding was a variceal size greater than 5 mm. However, among patients with varices greater than 5 mm (n = 196), there were no significant differences in the incidence of variceal bleeding between the 2 groups. Survival was also similar. Adverse effects were significantly more frequent in the propranolol + IS-MN group due to a greater incidence of headache. There were no significant differences in the incidence of new-onset or worsening ascites or in impairment of renal function. In conclusion, propranolol effectively prevents variceal bleeding. Adding IS-MN does not further decrease the low residual risk of bleeding in patients receiving propranolol. However, the long-term use of this combination drug therapy is safe and may be an alternative in clinical conditions associated with a greater risk of bleeding.

Nitric oxide and portal hypertension: a nitric oxide-releasing derivative of ursodeoxycholic acid that selectively releases nitric oxide in the liver

Portal hypertension, a common consequence of chronic liver diseases, is directly responsible for most complications of cirrhosis. In liver microcirculation, nitric oxide is considered a major fine tuner of vascular tone by counterbalancing vasoconstrictors (sympathetic nervous activity, the renin-angiotensin system, and endothelin-1) in normal and cirrhotic livers. The deficiency of endothelial nitric oxide release is a key factor in the hemodynamic abnormalities associated with the dynamic component of portal hypertension. Conventional nitric oxide donors release nitric oxide into the blood stream, causing systemic hypotension and progression of vasodilatory syndrome in cirrhotic patients. NCX1000 is a nitric oxide-releasing derivative of ursodeoxycholic acid-derived compounds, being capable of selectively releasing nitric oxide into the liver circulation. Administration of NCX1000 to portal hypertensive rats decreases intrahepatic resistance providing a novel therapy for the treatment of portal hypertension.

Low doses of isosorbide mononitrate attenuate the postprandial increase in portal pressure in patients with cirrhosis

Postprandial hyperemia is associated with a significant increase in portal pressure in cirrhosis, which may contribute to progressive dilation and rupture of gastroesophageal varices. In cirrhosis, an insufficient hepatic production of nitric oxide (NO) may impair the expected hepatic vasodilatory response to increased blood flow, further exaggerating the postprandial increase in portal pressure. This study was aimed at investigating whether low doses of an oral NO donor might counteract the postprandial peak in portal pressure. Twenty-three portal hypertensive cirrhotics, 8 of them under propranolol therapy, were randomized to receive orally 5-isosorbide mononitrate (ISMN; 10 mg; n = 11) or placebo (n = 12) and a standard liquid meal 15 minutes later. Hepatic venous pressure gradient (HVPG), mean arterial pressure (MAP), and hepatic blood flow (HBF) were measured at baseline and 15, 30, and 45 minutes after a meal. ISMN significantly attenuated the postprandial increase in portal pressure as compared with placebo (peak HVPG increase: 2.4 +/- 1.4 mm Hg vs. 5.2 +/- 2.1 mm Hg, P =.002). Percentual increases in HBF were similar in both groups. MAP decreased slightly in ISMN group (-7.5% +/-.5%; P <.01 vs. baseline). These effects were also observed in patients on chronic propranolol therapy. In conclusion, hepatic NO supplementation by low doses of ISMN effectively reduces the postprandial increase of portal pressure in cirrhosis, with only a mild effect on arterial pressure. The same was observed in patients receiving propranolol. Our results suggest that therapeutic strategies based on selective hepatic NO delivery may improve the treatment of portal hypertension.

Nitric oxide and portal hypertension

In liver cirrhosis, an increase in hepatic resistance is the initial phenomenon leading to portal hypertension. This is primarily due to the structural distortion of the intrahepatic microcirculation caused by cirrhosis. However, similar to other vascular conditions, architectural changes in the liver are associated with a deficient nitric oxide (NO) production, which results in an increased vascular tone with a further increase in hepatic resistance and portal pressure. New therapeutic strategies are being developed to selectively provide the liver with NO, overcoming the deleterious effects of systemic vasodilators. On the other hand, a strikingly opposite process occurs in splanchnic arterial circulation, where NO production is increased. This results in splanchnic vasodilatation and subsequent increase in portal inflow, which contributes to portal hypertension. Systemic blockade of NO in portal hypertension attenuates the hyperdynamic circulation, but its effects increasing hepatic resistance may offset the benefit of reducing portal inflow, thus preventing an effective reduction of portal pressure. Moreover, it cannot be ruled out that NO blockade may have a deleterious action on cirrhosis progression, which raises caution about their use in patients with cirrhosis.

Banding ligation versus nadolol and isosorbide mononitrate for the prevention of esophageal variceal rebleeding

BACKGROUND & AIMS

beta-blockers and banding ligation are effective in the prevention of variceal rebleeding. However, the relative efficacy and safety remains unresolved.

METHODS

One hundred twenty-one patients with a history of esophageal variceal bleeding were enrolled. Patients were randomized to undergo regular endoscopic variceal ligation (EVL group, 60 patients) until variceal obliteration, or drug therapy by using nadolol plus isosorbide mononitrate (N+I group, 61 patients) during the study period to prevent rebleeding.

RESULTS

After a median follow-up period of 25 months, recurrent upper gastrointestinal bleeding developed in 23 patients in the EVL group and 35 patients in the N+I group (P = 0.10). Recurrent bleeding from esophageal varices occurred in 12 patients (20%) in the EVL group and 26 patients (42%) in the N+I group (relative risk = 0.45; 95% confidence interval, 0.24-0.85). The actuarial probability of rebleeding from esophageal varices was lower in the EVL group (P = 0.01). The multivariate Cox analysis indicated that the treatment was the only factor predictive of rebleeding. Treatment failure occurred in 8 patients (13%) in the EVL group and 17 patients (28%) in the N+I group (P = 0.01). Fifteen patients in the EVL group and 8 patients of the N+I group died (P = 0.06). Complications occurred in 17% of the EVL group and in 19% of the N+I group (P = 0.6).

CONCLUSIONS

Our trial showed that ligation was more effective than nadolol plus isosorbide-5-mononitrate in the prevention of variceal rebleeding, with similar complications in both treatment modalities. However, there is no significant difference in the survival rate between the 2 groups.

Endoscopic ligation compared with combined treatment with nadolol and isosorbide mononitrate to prevent recurrent variceal bleeding

BACKGROUND

After an episode of acute bleeding from esophageal varices, patients are at high risk for recurrent bleeding and death. We compared two treatments to prevent recurrent bleeding--endoscopic ligation and combined medical therapy with nadolol and isosorbide mononitrate.

METHODS

We randomly assigned 144 patients with cirrhosis who were hospitalized with esophageal variceal bleeding to receive treatment with endoscopic ligation (72 patients) or the combined medical therapy (72 patients). Sessions of ligation were repeated every two to three weeks until the varices were eradicated. The initial dose of nadolol was 80 mg orally once daily, with adjustment according to the resting heart rate; isosorbide mononitrate was given in increasing doses, beginning at 20 mg once a day at bed time and rising over the course of one week to 40 mg orally twice a day, unless side effects occurred. The primary end points were recurrent bleeding, complications, and death.

RESULTS

The median follow-up period was 21 months. A total of 35 patients in the ligation group and 24 in the medication group had recurrent bleeding. The probability of recurrence was lower in the medication group, both for all episodes related to portal hypertension (P=0.04) and for recurrent variceal bleeding (P=0.04). There were major complications in nine patients treated with ligation (seven had bleeding esophageal ulcers and two had aspiration pneumonia) and two treated with medication (both had bradycardia and dyspnea) (P=0.05). Thirty patients in the ligation group died, as did 23 patients in the medication group (P=0.52). The probability of recurrent bleeding was lower for patients with a hemodynamic response to therapy, defined as a decrease in the hepatic venous pressure gradient of more than 20 percent from the base-line value or to less than 12 mm Hg (18 percent, vs. 54 percent in patients with no hemodynamic response at one year; P<0.001), and the probability of survival was higher (94 percent vs. 78 percent at one year, P=0.02).

CONCLUSIONS

Combined therapy with nadolol and isosorbide mononitrate is more effective than endoscopic ligation for the prevention of recurrent bleeding and is associated with a lower rate of major complications. A hemodynamic response to treatment is associated with a better long-term prognosis.

Management of portal hypertension after variceal hemorrhage

Each variceal bleed is associated with 20% to 30% risk of dying. Management of portal hypertension after a bleed consists of (1) control of bleeding and (2) prevention of rebleeding. Effective control of bleeding can be achieved either pharmacologically by administering somatostatin or octreotide or endoscopically via sclerotherapy or variceal band ligation. In practice, both pharmacologic and endoscopic therapy are used concomitantly. Rebleeding can be prevented by endoscopic obliteration of varices. In this setting, variceal ligation is the preferred endoscopic modality. B-blockade is as effective as endoscopic therapy and, in combination, the two modalities may be additive.

Review article: a drug therapy for the prevention of variceal haemorrhage

The development of varices is a major complication of cirrhosis, and variceal haemorrhage has a high mortality. There have been major advances in the primary and secondary prevention of variceal haemorrhage over the last 20 years involving endoscopic, radiological and pharmacological approaches. This review concentrates principally on drug therapy, particularly on the numerous haemodynamic studies. Many of these drugs have not been studied in clinical trials, but provide data about the underlying pathogenesis of portal hypertension. Also covered in this review are the randomized controlled trials and meta-analyses that involve a large number of patients. These trials involve relatively few drugs such as non-selective beta-blockers and nitrates. Correlations between haemodynamic and clinical parameters are discussed. Despite the recent increase in the use of alternative endoscopic therapies, an effective and well tolerated drug remains a clinically important research goal.

Acute and chronic effects of isosorbide-5-mononitrate administration on effective renal plasma flow and the renin-aldosterone system in cirrhotic patients

BACKGROUND AND AIMS

Isosorbide-5-mononitrate (ISMO) has been shown to be effective in reducing the risk of variceal bleeding in patients with cirrhosis. However, recent studies have suggested that this drug compromises renal function. The present study was conducted to assess the acute and chronic effects of ISMO on effective renal plasma flow (ERPF) and the renin-aldosterone profile in cirrhotic patients.

METHODS

Fifteen cirrhotic patients were included in the present study. The mean arterial pressure (MAP), heart rate (HR), serum renin concentration (SR), ERPF and plasma aldosterone concentration (PA) were checked before ISMO treatment (baseline study), after a single oral dose of 20 mg ISMO (acute effect study) and after 3 weeks of ISMO treatment (chronic effect study).

RESULTS

Our data showed that the oral administration of a single dose (20 mg) of ISMO to cirrhotic patients was associated with significant decreases in ERPF (from 405.18 to 369.06 mL/min) and MAP (from 93.26 to 86.40 mmHg), and increases in HR (from 65.53 to 70.06 beats/min), SR (from 24.15 to 54.41 pg/mL), and PA (from 105.1 to 148.7 pg/mL). However, no significant changes were observed in HR, MAP, PA, SR, or ERPF after 3 weeks of ISMO treatment when compared with the baseline study.

CONCLUSIONS

The administration of ISMO causes a decrease in ERPF in cirrhotic patients and its use in patients with renal impairment should be considered cautiously.

Esophageal varices. I. Clinical presentation, medical therapy, and endoscopic therapy

The last half century has witnessed great advances in the understanding of the pathogenesis and natural history of portal hypertension in cirrhotics. Several pharmacologic and endoscopic techniques have been developed for the treatment of portal hypertension. The use of these agents in a given patient must be based on an understanding of the stage in the natural history of the disease and the relative efficacy and safety of the available treatment options.

Complications of cirrhosis. I. Portal hypertension

Increased resistance to portal blood flow is the primary factor in the pathophysiology of portal hypertension, and is mainly determined by the morphological changes occurring in chronic liver diseases. This is aggravated by a dynamic component, due to the active-reversible- contraction of different elements of the porto-hepatic bed. A decreased synthesis of NO in the intrahepatic circulation is the main determinant of this dynamic component. This provides a rationale for the use of vasodilators to reduce intrahepatic resistance and portal pressure. Another factor contributing to aggravate the portal hypertension is a significant increase in portal blood flow, caused by arteriolar splanchnic vasodilation and hyperkinetic circulation. Splanchnic arteriolar vasodilation is a multifactorial phenomenon, which may involve local (endothelial) mechanisms as well as neurogenic and humoral pathways. Most pharmacological treatments have been aimed at correcting the increased portal blood inflow by the use of splanchnic vasoconstrictors, such as beta-blockers, vasopressin derivatives and somatostatin. Several studies have demonstrated that changes in the hepatic venous pressure gradient (HVPG) during maintenance therapy are useful to identify those patients who are going to have a variceal bleeding or rebleeding. The wide individual variation in the HVPG response to pharmacological treatment makes it desirable to schedule follow-up measurements of HVPG during pharmacological therapy. A priority for research in the forthcoming years is to develop accurate non-invasive methods to assess prognosis, which can be used to substitute or as surrogate indicators of the HVPG response. In the clinical management of portal hypertension, beta-blockers are at present the only accepted treatment for the prevention of variceal bleeding. Whether the association of isosorbide-5-mononitrate will improve the high efficacy of beta-blockers is questionable. The efficacy of more aggressive techniques, such as endoscopic band ligation, should be further tested against beta-blockers in patients with a high risk of bleeding. In the treatment of acute variceal bleeding, administration of somatostatin or terlipressin is an established therapy. It may be used alone or, preferably, as an initial treatment before sclerotherapy or endoscopic band ligation. No more than two sessions of endoscopic treatment should be used to control the bleeding. If the bleeding is not easily controlled, other alternatives such as transjugular intrahepatic portosystemic shunts (TIPS) or derivative surgery should be considered, the former being the best in patients with poor liver function. Recent studies suggest that early measurement of HVPG during variceal bleeding may be used as a guide for therapeutic decisions in the treatment of patients with acute variceal bleeding. Those patients with a high HVPG have a high risk of poor evolution, and may be candidates for more intensive and aggressive therapy, such as surgery or TIPS. Those with lower HVPG have a very high probability of an uneventful evolution, and may thus be managed more conservatively using medical and endoscopic treatments. Pharmacological agents (propranolol or nadolol), endoscopic treatment (preferably banding ligation) or surgery can be used to prevent rebleeding. A pending task for the new millennium is to assess whether the early treatment of asymptomatic, compensated cirrhotic patients with portal pressure reducing agents can prevent the development of esophageal varices and of other complications of portal hypertension.

Long-term results of a clinical trial of nadolol with or without isosorbide mononitrate for primary prophylaxis of variceal bleeding in cirrhosis

It is clearly established that beta-blockers decrease the risk of a first variceal bleeding in cirrhosis. We have recently shown that the addition of isosorbide mononitrate to nadolol decreases the rate of variceal bleeding in patients with cirrhosis and varices, compared with nadolol alone, after a median follow-up of 30 months. It is not established if the long-term treatment with the combination continues to be beneficial. Therefore, we assessed the long-term effect of this combination on first variceal bleeding, complications, and death. One hundred forty-six cirrhotic patients with esophageal varices included in a previously published multicenter, randomized study comparing nadolol (40-160 mg/d) with the combination nadolol plus isosorbide mononitrate (10-20 mg 3 times per day) were followed up for up to 7 years (median follow-up, 55 months). The primary end-point was variceal bleeding of any severity. Twenty-four patients (16 in the nadolol group, and 8 in the combination group) experienced variceal bleeding (log rank test, P =.02). Cumulative risk of bleeding was 29% and 12%, respectively (95% CI for the difference, 1%-23%). Two and 4 patients, respectively, had bleeding from portal hypertensive gastropathy (log rank test, P =.20). Thirty and 25 patients, respectively, died during follow-up (log rank test, P =.13). Twelve and 10 patients, respectively, had de novo occurrence of ascites during follow-up (log rank test, P =.29). In conclusion, nadolol plus isosorbide mononitrate is significantly more effective than nadolol alone in the long-term use. Side effects are few, and no deleterious effects on ascites occurrence or on survival occur after long-term use of this combination.

Carvedilol, a new nonselective beta-blocker with intrinsic anti- Alpha1-adrenergic activity, has a greater portal hypotensive effect than propranolol in patients with cirrhosis

Only some patients show a substantial hepatic venous pressure gradient (HVPG) reduction after propranolol, which makes it desirable to investigate drugs with greater portal hypotensive effect. The aim of this study was to investigate whether carvedilol, a nonselective beta-blocker with anti-alpha1-adrenergic activity, may cause a greater HVPG reduction than propranolol. Thirty-five cirrhotic patients had hemodynamic measurements before and after the random administration of carvedilol (n = 14), propranolol (n = 14), or placebo (n = 7). Carvedilol markedly reduced HVPG, from 19.5 +/- 1.3 to 15.4 +/- 1 mm Hg (P <.0001). This HVPG reduction was greater than after propranolol (-20.4 +/- 2 vs. -12.7 +/- 2%, P <.05). Moreover, carvedilol decreased HVPG greater than 20% of baseline values or to </=12 mm Hg in a greater proportion of patients (64% vs. 14%, P <.05). Both drugs caused similar reductions in hepatic and azygos blood flows, suggesting that the greater HVPG decrease by carvedilol was because of reduced hepatic and portocollateral resistance. Propranolol caused greater reductions in heart rate and cardiac output than carvedilol, whereas carvedilol caused a greater decrease in mean arterial pressure (-23.1 vs. -11%, P <.05). Thus, carvedilol has a greater portal hypotensive effect than propranolol in patients with cirrhosis, suggesting a greater therapeutic potential. However, it causes arterial hypotension, which calls for careful evaluation before its long-term use.

Acute and chronic haemodynamic and renal effects of carvedilol in patients with cirrhosis

BACKGROUND/AIMS

Recent reports have suggested that the vasodilating beta-blocker carvedilol may have beneficial acute haemodynamic effects in cirrhotic portal hypertension. However, no data exist on chronic use or renal effects in this patient group. The aim of this study was to assess the acute and chronic haemodynamic and renal effects of carvedilol in cirrhotic patients.

METHODS

Seventeen cirrhotic patients (mean age 55.2+/-2.8, mean Child-Pugh score 7.4+/-0.5) were studied. Hepatic venous pressure gradient, cardiac output, systemic vascular resistance, mean arterial pressure, heart rate and hepatic blood flow were measured before and 1 h after 25 mg carvedilol. After 4 weeks of therapy with carvedilol 25 mg daily, these measurements were repeated before and after rechallenge with carvedilol. Urine volume, sodium excretion and creatinine clearance were also measured before and after 4 weeks of therapy.

RESULTS

Seven patients did not complete the 4-week carvedilol therapy due to hypotension or poor compliance. Hepatic venous pressure gradient fell by 20.8% acutely (p<0.001) and by 16.3% after 4 weeks of therapy (p<0.002). Heart rate, mean arterial pressure and cardiac output fell after acute administration of carvedilol, but only heart rate fell significantly after 4 weeks of treatment. Hepatic blood flow, urine volume, sodium excretion and creatinine clearance remained unchanged after therapy.

CONCLUSION

Carvedilol has beneficial effects on splanchnic haemodynamics following acute and chronic administration in cirrhosis, without compromising hepatic blood flow or renal function. However, a substantial number of patients cannot tolerate 25 mg daily.

Effect of losartan, an angiotensin II receptor antagonist, on portal pressure in cirrhosis

Administration of angiotensin II causes an increase in portal pressure, and plasma concentration of angiotensin II is elevated in patients with cirrhosis, suggesting that angiotensin II may be involved in the pathogenesis of portal hypertension in cirrhosis. We evaluated the effect of the orally active angiotensin II receptor antagonist, losartan, on portal pressure in patients with cirrhosis and portal hypertension. Thirty patients with severe (hepatic venous pressure gradient [HVPG] >/= 20 mm Hg) and 15 patients with moderate (HVPG < 20 mm Hg) portal hypertension at baseline measurement were treated with an oral dose of 25 mg losartan once daily for 1 week and compared with 15 (HVPG >/= 20 mm Hg) and 10 (HVPG < 20 mm Hg), respectively, cirrhotic controls. On the seventh day, HVPG was determined again, and blood pressure, heart rate, body weight, and parameters of liver and kidney function were recorded. Losartan induced a significant (P <.001) decrease of HVPG in the patients with severe (-46.8% +/- 15.5%) and moderate (-44.1% +/- 14.7%) portal hypertension, while no significant change was seen in the controls. Losartan caused a slight but significant (P <.01) fall in mean arterial blood pressure (-3.1 +/- 5.0 and -3.5 +/- 4.3 mm Hg, respectively). One patient treated with losartan had a short symptomatic hypotensive reaction after the first dose of losartan that did not recur despite continued treatment. No deterioration of liver or kidney function was observed. The present study indicates that angiotensin II blockade with orally administered losartan is safe and highly effective in the treatment of portal hypertension.

Propranolol plus prazosin compared with propranolol plus isosorbide-5-mononitrate in the treatment of portal hypertension

BACKGROUND & AIMS

The association of prazosin to propranolol enhances the decrease in portal pressure but may cause hypotension and sodium retention. The aim of this study was to compare the portal pressure reduction and safety of the combination of propranolol plus prazosin with that of propranolol plus isosorbide-5-mononitrate (ISMN).

METHODS

Fifty-six portal-hypertensive cirrhotics received randomly propranolol plus prazosin (n = 28) or propranolol plus ISMN (n = 28) orally for 3 months. Hemodynamics and liver and renal function were assessed at baseline and after 3 months.

RESULTS

Propranolol plus prazosin caused a greater reduction in hepatic venous pressure gradient (HVPG) than propranolol plus ISMN (-24.2% +/- 11% vs. -16.1% +/- 11%; P < 0.01). A reduction in HVPG of > 20% was significantly more frequent in the propranolol plus prazosin group than in the propranolol plus ISMN group (85% vs. 53%; P < 0.05). Neither treatment modified hepatic blood flow, quantitative liver function test results, glomerular filtration rate, plasma renin activity, or plasma aldosterone level. Side effects occurred in 13 patients receiving propranolol plus prazosin compared with 7 receiving propranolol plus ISMN (P = 0.16).

CONCLUSIONS

Propranolol plus prazosin has a greater portal pressure-lowering effect than propranolol plus ISMN. Both therapies were safe for liver and renal function. However, the combination of propranolol plus prazosin caused a greater decrease in arterial pressure and was less well tolerated than propranolol plus ISMN.

Pharmacological prevention of variceal bleeding. New developments

The introduction of pharmacological therapy has been one of the major advances in the treatment of the complications of portal hypertension. Many drugs have been shown to reduce portal hypertension in patients with cirrhosis. However, the most widely used drugs and the only ones for which there is sufficient evidence, are the beta-blockers. These drugs have been, up to now, the only accepted prophylactic therapy for oesophageal variceal bleeding and are also an alternative treatment to sclerotherapy or surgery to prevent variceal rebleeding. A reduction in portal pressure gradient by beta-blockers below 12 mmHg or by more than 20% of baseline values is associated with almost a total protection from oesophageal bleeding. Such a marked response in portal pressure is only achieved in some patients receiving propranolol. New pharmacological approaches with a greater portal pressure reducing effect may improve the beneficial effect of drugs in preventing variceal bleeding. The more promising approach is the combined administration of beta-blockers and isosorbide-5-mononitrate, which has been shown to potentiate the reduction in portal pressure and to be highly effective in initial randomized clinical trials.

Surgery in portal hypertension

The role of surgery in portal hypertension remains a topic of debate. For the past 100 years, various surgical procedures have been used to treat variceal bleeding, refractory ascites, and end-stage liver disease. The past decade has seen significant advances in pharmacotherapy, endoscopy, interventional radiology, and surgery for the management of patients with portal hypertension. Liver transplantation has come of age in the 1990s and is now an accepted therapy for patients with end-stage liver disease. The wide array of management options can complicate the decision making process and defines the need to evaluate these patients fully. Factors such as the aetiology and extent of liver disease, response to prior medical, endoscopic, and other interventional treatments, and possibility of future liver transplantation must be considered. This manuscript will review the history of surgical treatments of portal hypertension, describe the surgical procedures with their advantages and disadvantages, and evaluate their role in the elective and emergent settings.

The role of surgery in the treatment of portal hypertension

The role of surgery in the treatment of portal hypertension continues to evolve. Pharmacologic and endoscopic therapies are the primary treatment modalities for the prophylaxis and treatment of variceal bleeding and ascites. Failure of these therapies is the indication for invasive intervention such as TIPS, surgical shunt, or devascularization. Distal splenoreal shunting provides selective variceal decompression with less encephalopathy and accelerated hepatic failure than portal decompression. Liver transplantation remains the treatment of choice for patients with poor hepatic function.

Hyperdynamic circulation in patients with cirrhosis: direct measurement of nitric oxide levels in hepatic and portal veins

BACKGROUND/AIMS

Peripheral vasodilation represents the main vascular dysfunction associated with the hyperdynamic circulation of liver cirrhosis. This study was intended to measure directly regional and systemic levels of nitric oxide, a potent vasorelaxing mediator, in order to assess its role in the development of hemodynamic changes of cirrhosis.

METHODS

We compared nitric oxide levels in the splanchinic and systemic circulation of 25 patients with cirrhosis undergoing transjugular intrahepatic portosystemic stent shunt and in the hepatic vein and peripheral blood of 10 patients without cirrhosis submitted to venous catheterization. Nitric oxide levels were measured through electron paramagnetic resonance spectroscopy as nitrosylhemoglobin complexes.

RESULTS

Significantly higher nitric oxide levels were calculated in patients with cirrhosis with respect to controls, both in the peripheral and hepatic veins. In patients with cirrhosis, nitric oxide levels in the portal vein (3.44 +/- 2.17, expressed in arbitrary units) were higher than in the systemic circulation (1.89 +/- 1.15), but lower than in the hepatic vein (4.75 +/- 2.53; p < 0.001 by variance analysis).

CONCLUSIONS

These data suggest that nitric oxide synthetic pathway activity as well as nitric oxide release are enhanced at the level of splanchnic vasculature and, more important, in the hepatic tissue, confirming evidence of the predominant role of nitric oxide in the pathogenesis of hemodynamic changes in patients with cirrhosis with portal hypertension.

Acute haemodynamic changes after oral carvedilol, a vasodilating beta-blocker, in patients with cirrhosis

BACKGROUND/AIMS

Combinations of beta-blockers and vasodilators have been assessed for their ability to lower portal pressure and so prevent variceal haemorrhage. However, reservations have been raised particularly with respect to renal function and perfusion after the use of these medicines in patients with chronic liver disease. We studied the acute effects of carvedilol, a new vasodilating beta-blocker which combines non-selective beta-blockade with alpha-1 receptor antagonism, upon the haemodynamics of patients with cirrhosis.

METHODS

Sixteen patients completed the study which measured the changes approximately 1 h after the administration of 25 mg oral carvedilol.

RESULTS

The hepatic venous pressure gradient fell from 16.7 +/- 0.9 to 13.6 +/- 1.0 mmHg (p < 0.00001), accounted for largely by reductions in the wedged hepatic venous pressure. Despite this, the azygos blood flow did not change. There was a significant fall in mean arterial pressure (94.8 +/- 4.4 cf. 84.6 +/- 4.3 mmHg; p = 0.0001), which was particularly apparent in the diastolic blood pressure of those patients with ascites. The heart rate only fell significantly in the ascitic subjects. No significant changes occurred in the cardiac output or systemic vascular resistance. Unilateral renal vein flow as measured by the reverse thermodilution technique remained constant.

CONCLUSIONS

Carvedilol is therefore a potent acute portal hypotensive agent which does not appear to compromise renal perfusion. However, patients with ascites are at greater risk of its systemic hypotensive action.

Nadolol plus isosorbide mononitrate compared with sclerotherapy for the prevention of variceal rebleeding

BACKGROUND

Patients who have bleeding from esophageal varices are at high risk for rebleeding and death. We compared the efficacy and safety of endoscopic sclerotherapy with the efficacy and safety of nadolol plus isosorbide mononitrate for the prevention of variceal rebleeding.

METHODS

Eighty-six hospitalized patients with cirrhosis and bleeding from esophageal varices diagnosed by endoscopy were randomly assigned to treatment with repeated sclerotherapy (43 patients) or nadolol plus isosorbide-5-mononitrate (43 patients). The primary outcomes were rebleeding, death, and complications. The hepatic venous pressure gradient was measured at base line and after three months.

RESULTS

Base-line data were similar in the two groups, and the median follow-up was 18 months in both. Eleven patients in the medication group and 23 in the sclerotherapy group had rebleeding. The actuarial probability of remaining free of rebleeding was higher in the medication group for all episodes related to portal hypertension (P = 0.001) and variceal rebleeding (P = 0.002). Four patients in the medication group and nine in the sclerotherapy group died (P = 0.07 for the difference in the actuarial probability of survival). Seven patients in the medication group and 16 in the sclerotherapy group had treatment-related complications (P = 0.03). Thirty-one patients in the medication group underwent two hemodynamic studies; 1 of the 13 patients with more than a 20 percent decrease in the hepatic venous pressure gradient had rebleeding, as compared with 8 of the 18 with smaller decreases in the pressure gradient (P = 0.04) for the actuarial probability of rebleeding at two years).

CONCLUSIONS

As compared with sclerotherapy, nadolol plus isosorbide mononitrate significantly decreased the risk of rebleeding from esophageal varices.

Long-term effect of nadolol or nadolol plus isosorbide-5-mononitrate on renal function and ascites formation in patients with cirrhosis. GTIP Gruppo Triveneto per l'Ipertensione Portale

The association beta-blockers plus nitrates has been reported to impair renal function and renal sodium handling, leading to increased risk of development of ascites, or worsening of a preexisting ascites, or increase in the requirements of diuretic agents. In 81 patients with cirrhosis and esophageal varices, participating in a multicenter controlled clinical trial of prophylaxis of variceal bleeding comparing nadolol (NAD) plus isosorbide-5-mononitrate (I5M) with NAD alone, renal function, presence of ascites, and diuretic requirements were assessed at inclusion and after 6 months of follow-up. No significant variation in s-urea or s-creatinine was observed in either group, Three patients in the nadolol group and two in the NAD plus I5M developed ascites at 6 months (P = .70), and a need to increase diuretic regimen was observed in four and three patients, respectively (P = .76). Decrease in heart rate and in mean arterial pressure was similar in the two groups. There was a significant correlation between increases in s-creatinine and decrease in mean arterial pressure in the whole series (P = .015). Only in patients treated with the association was there a significant larger proportion of patients ascitic who became anascitic, than of patients anascitic who became ascitic (P = .03). In patients treated with the association, there was a significantly larger decrease in hepatic venous pressure gradient (P = .05). It is concluded that patients treated with the association NAD plus I5M are not at increased risk of developing renal dysfunction or worsening of ascites compared with patients treated with NAD alone.(ABSTRACT TRUNCATED AT 250 WORDS)