[Acute-on-chronic liver failure: a diagnostic and therapeutic challenge for intensive care]

Das akut-auf-chronische Leberversagen („acute-on-chronic liver failure“, ACLF) ist ein emergentes Krankheitssyndrom, das durch einen oder mehrere akute Trigger bei vorgeschädigter Leber ausgelöst wird und vom progressiven hepatalen und nichthepatalen Organversagen, einem gravierenden Risiko infektiöser Komplikationen sowie hoher kurzfristiger Letalität gekennzeichnet ist. Wenngleich pathophysiologisch noch weitgehend unverstanden erfordert das ACLF frühzeitige diagnostische und therapeutische Maßnahmen, die sich auf zugrunde liegende Ursachen sowie das Verhindern von Komplikationen richten, um die Prognose betroffener Patienten zu verbessern.

Portopulmonary hypertension

Portopulmonary hypertension (PoPH) refers to the condition that pulmonary arterial hypertension (PAH) occur in the stetting of portal hypertension. The development of PoPH is thought to be independent of the severity of portal hypertension or the etiology or severity of liver disease. PoPH results from excessive vasoconstriction, vascular remodeling, and proliferative and thrombotic events within the pulmonary circulation that lead to progressive right ventricular failure and ultimately to death. Untreated PoPH is associated with a poor prognosis. As PoPH is frequently asymptomatic or symptoms are generally non-specific, patients should be actively screened for the presence of PoPH. Two-dimensional transthoracic echocardiography is a useful non-invasive screening tool, but a definitive diagnosis requires invasive hemodynamic confirmation by right heart catheterization. Despite a dearth of randomized, prospective data, an ever-expanding clinical experience shows that patients with PoPH benefit from therapy with PAH-specific medications including with endothelin receptor antagonists, phosphodiesterase-5 inhibitors, and/or prostanoids. Due to high perioperative mortality, transplantation should be avoided in those patients who have severe PoPH that is refractory to medical therapy.

Cirrhotic Multiorgan Syndrome

Patients with cirrhosis and portal hypertension are at an increased risk of the development of circulatory dysfunction that may potentially result in multiple organ failure. Apart from the liver, this may involve the heart, lungs, kidneys, the immune system, the adrenal glands, and other organ systems. As the disease progresses, the circulation becomes hyperdynamic, and signs of cardiac, pulmonary, and renal dysfunction are observed, in addition to reduced survival. Infections and an altered cardiac function known as cirrhotic cardiomyopathy may be precipitators for the development of other complications such as hepatorenal syndrome. In patients with chronic organ dysfunction, various precipitating events may induce an acute-on-chronic renal failure and acute-on-chronic liver failure that negatively affect the prognosis. Future research on the pathophysiologic mechanisms of the complications and the precipitating factors is essential to understand the basics of the treatment of these challenging conditions. The aim of the present review is to focus on the development and precipitating factors of various organ failures in patients with decompensated cirrhosis.

[Hepatocardiac disorders : Interactions between two organ systems]

Interactions between the hepatic portal and cardiovascular systems are frequently found in patients with liver disease. Cirrhotic cardiomyopathy (CCMP) is defined as reduced cardiac function in patients with liver cirrhosis in the absence of other known causes of cardiac disease. The typical hyperdynamic circulatory state by means of increased cardiac output and reduced systemic vascular resistance may mask left ventricular failure. Portopulmonary hypertension (POPH) is defined as increased pulmonary arterial pressure and the presence of portal hypertension, and is associated with increased mortality. Targeted medical therapies include vasodilators such as prostanoids, endothelin receptor antagonists and phosphodiesterase-5 inhibitors. Hypoxic or ischaemic hepatitis (HH) is defined by a sharp increase of serum aminotransferase levels due to liver cell necrosis as result of cardiac, circulatory or respiratory failure. An overview of these diseases is provided in this article.

Von Willebrand factor antigen for detection of hepatopulmonary syndrome in patients with cirrhosis

BACKGROUND & AIMS

Hepatopulmonary syndrome (HPS) occurs in 20-30% of patients with liver cirrhosis and is associated with a >2 fold increased mortality. Endothelial dysfunction seems to play a central role in its pathogenesis. von Willebrand factor antigen (vWF-Ag), an established marker of endothelial dysfunction, is significantly elevated in patients with liver cirrhosis, portal hypertension, and in experimental HPS. Aim of the present study was to evaluate the impact of vWF-Ag as a screening marker for presence of HPS in patients with stable cirrhosis.

METHODS

145 patients with stable liver cirrhosis were screened for presence of HPS in this prospective cohort type cross sectional diagnostic study. vWF-Ag and SaO2 levels were assessed at time of screening for HPS. Criteria of HPS were fulfilled in 31 (21%) patients.

RESULTS

vWF-Ag levels were significantly higher in patients with HPS compared to patients without HPS (p<0.001). Furthermore, vWF-Ag correlated significantly with gas exchange in HPS positive patients (p<0.05). vWF-Ag is an independent predictor of HPS after correction for sex, age, model for endstage-liver disease (MELD), and hepatic venous pressure gradient (HVPG) (OR per 1% increase of vWF-Ag: 1.02, 95% CI: 1.00-1.04, p<0.05). The best cut-off was 328% at a sensitivity of 100% and specificity of 53.5%; positive predictive value: 36.9%; negative predictive value: 100%.

CONCLUSIONS

HPS is associated with elevated vWF-Ag levels. vWF-Ag may be a useful screening tool for early detection of HPS. Further studies investigating vWF-Ag in HPS will be needed to confirm our findings.

[Pulmonary complications in liver diseases]

Pulmonary-hepatic vascular disorders are frequent complications in patients with portal hypertension and cirrhosis. Hepatopulmonary syndrome (HPS), portopulmonary hypertension (POPH), and hepatic hydrothorax are relevant disease entities in these patients. HPS occurs in up to 30 % of patients with cirrhosis and is associated with a more than 2-fold increased mortality. The diagnosis of HPS should be established early by arterial blood gas analysis and contrast-enhanced echocardiography, whereas POPH is diagnosed by the presence of pulmonary arterial hypertension evaluated via right heart catheterization and the presence of portal hypertension. Therapeutic options include initiation of long-term oxygen therapy and liver transplantation in patients with severe HPS. Patients with POPH should receive targeted medical therapies with endothelin receptor antagonists, phosphodiesterase-5 inhibitors and/or prostanoids. In contrast, β-blockers should be avoided. This review summarizes current knowledge regarding pulmonary-hepatic vascular disorders, with a focus on HPS.