Portopulmonary hypertension and hepatopulmonary syndrome

Differential diagnosis of hepatopulmonary syndrome (HPS): Portopulmonary hypertension (PPH) and hereditary hemorrhagic telangiectasia (HHT)

Hepatopulmonary syndrome (HPS) is a severe complication of advanced liver disease associated with an extremely poor prognosis. HPS is diagnosed in 4-47% of patients with cirrhosis and in 15-20% of candidates for liver transplantation. In addition, severe hypoxia is associated with a high risk of complications of liver transplantation (a 30% chance during the first 90 days) and increases the gap between transplantation and improving arterial oxygenation. The pathogenesis of HPS is not fully understood, and no effective pharmacological treatment has been developed yet. Currently, the treatment of choice for HPS is orthotopic liver transplantation. Non-specific clinical criteria and the lack of standardized diagnostic criteria for determining HPS can lead to diagnostic errors. Portopulmonary hypertension and hereditary hemorrhagic telangiectasia, also known as Osler-Weber-Rendu syndrome, are pulmonary complications of liver disease which should be differentially diagnosed from HPS.

The relationship between severity of liver cirrhosis and pulmonary function tests

Pulmonary complications, mainly hepatopulmonary syndrome (HPS), are frequently observed in liver cirrhosis. In this study, the aim was to investigate the frequency of hypoxemia and impairment of pulmonary function tests (PFT) in patients with liver cirrhosis and to examine the relationships of these impairments with liver failure. A total of 39 patients with cirrhosis, 24 males and 15 females, were included in our study. The mean age of the patients was 47.5 +/- 17.2 years. Arterial blood gases, PFT, and carbon monoxide diffusion tests (DLCO) were performed in all patients. Out of 39 cirrhotic patients, 21 (53.8%) had ascites, whereas 18 (46.2%) did not. Seven patients were in the Child-Pugh A group, 21 in the Child-Pugh B group, and 11 patients were in the Child-Pugh C group. Hypoxia was found in 33.3% of the patients. Although the PaO2 and SaO2 values of patients with ascites were lower compared to those without ascites (P < 0.05), no statistically significant difference was determined in the comparison of hypoxia between the groups (P > 0.05). Among the PFT parameters, FEV1/FVC and FEF25-75% values were found to be lower in patients with ascites than those without (P < 0.05). No differences were established between these two groups of patients in terms of DLCO (P > 0.05). While no differences were found in comparison of the DLCO values in between the groups (P > 0.05), there was a statistically significant difference in the ratio of DLCO to the alveolar ventilation (DLCO/VA) in between the groups (P < 0.05). On the other hand, a negative correlation was found between the DLCO/VA and Child points when the relationship between the Child-Pugh score and PFT parameters were investigated (r = -0.371, P < 0.05). Consequently, a relationship was established between the severity of liver failure and diffusion tests showing pulmonary complications invasively. We believe diffusions tests should be performed in addition to the PFT in order to determine pulmonary involvements particularly in patients who are candidates for liver transplantation.

Current concepts in the management of hepatopulmonary syndrome

The hepatopulmonary syndrome is characterized as the triad of liver disease, pulmonary gas exchange abnormalities leading to arterial deoxygenation and evidence of intrapulmonary vascular dilatations. This review summarizes the pathological mechanisms leading to pulmonary vascular changes in hepatopulmonary syndrome. The role of the three currently used diagnostic imaging modalities of contrast-enhanced echocardiography, perfusion lung scanning and pulmonary arteriography that identify the presence of intrapulmonary vascular abnormalities are reviewed. Liver transplantation is considered to be the definitive treatment of hepatopulmonary syndrome with often successful reversal of hypoxemia, however other treatments have been trialed. This review further appraises the evidence for the use of pharmacological agents and the role of radiological interventions in hepatopulmonary syndrome.

Sildenafil for portopulmonary hypertension in a patient undergoing liver transplantation

Liver transplantation (LT) may be indicated in cirrhotic patients with underlying pulmonary artery hypertension. However, severe pulmonary artery hypertension with mean pulmonary artery pressure (mPAP) above 50 mmHg has even been considered a contraindication to LT. We present a cirrhotic patient with an mPAP of 56 mmHg measured using right heart catheterization (RHC) and with severely compromised physical capacity. She was first treated with sildenafil (Viagra), a potent novel vasodilator, and successfully transplanted later. The mPAP decreased with sildenafil to the level of 28-31 mmHg and her general condition improved markedly. An LT using piggyback technique was performed 16 weeks later. Despite 2 reoperations for bleeding, the outcome has been excellent. In conclusion, treatment of severe portopulmonary hypertension (PHT) with sildenafil is effective. If a decrease in mPAP is achieved with sildenafil, it may improve the result of LT, even though no evidence of reversibility of PPHTN exists.

Glutamine and acute illness

This is a literature review over a time period of the past 2 years concerning glutamine in clinical nutrition. Emphasis is put upon studies of glutamine in clinical settings, but a brief overview of the large range of literature over the role of glutamine in various experimental settings is also included. The most interesting concept for the past 2 years is the suggestion to use plasma glutamine concentration at admission to the intensive care unit as a prognostic marker and as a possible indicator for indication of glutamine supplementation.