Portopulmonary hypertension: from diagnosis to treatment

Liver dysfunction in idiopathic pulmonary arterial hypertension: prevalence, characteristics and prognostic significance, a retrospective cohort study in China

OBJECTIVES

The aim was to elucidate the relationship between liver function and idiopathic pulmonary arterial hypertension (IPAH).

DESIGN AND SETTING

Retrospective, longitudinal study in urban tertiary care centre in Shanghai, China.

PARTICIPANTS

407 IPAH consecutive incident patients age 18-65 years were retrospectively enrolled from January 2008 to December 2018.

OUTCOME MEASUREMENTS

The primary endpoint was all-cause mortality. The cut-off value was determined by receiver operating characteristic curve (ROC), which was validated by Cox proportional hazard model was internally validated by bootstrap analysis and used for survival analysis. The Cox model was (internally) validated and cross-validated areas under the curve (AUC) should be reported.

RESULTS

The prevalence of abnormal liver function tests (LFTs) at baseline was 77.6%. Hyperbilirubinaemia is the most common abnormal biochemical liver test: abnormal total bilirubin (TBIL in 51.6% patients). During the follow-up, 160 patients died. Patients with mixed liver dysfunction have worse prognosis than those with normal LFTs or isolated abnormal bilirubin metabolism. Comparing with patients with hepatocellular injury, the survival of patients with abnormal bilirubin metabolism is lower. Multivariable Cox models revealed a positive association between TBIL, γ-glutamyltransferase (GGT) and mortality showing that each Ig increment in TBIL and GGT was associated with a higher all-cause mortality (TBIL: HR 4. 29 (95% CI 1. 21 to 15. 27), p=0. 02; GGT: HR 2. 76 (95% CI 1. 18 to 6. 45), p=0. 02). A novel formula named Liver Function Predict Index (LFPI) was constructed (LFPI=-0.002*6MWD+1.014*lg GGT+1.458*lg TBIL) to predict prognosis. ROC curve analysis did further identify 2.729 as the best cut-off value for LFPI (AUC 0.75, p<0.001, sensitivity 79%, specificity 70%).

CONCLUSIONS

Liver dysfunction is frequent in IPAH, and characterised by a predominantly cholestatic enzyme profile. LFTs abnormalities are associated with worse survival and LFPI was a new and simple predictor for prognosis of IPAH.

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.

Extrahepatic complications to cirrhosis and portal hypertension: Haemodynamic and homeostatic aspects

In addition to complications relating to the liver, patients with cirrhosis and portal hypertension develop extrahepatic functional disturbances of multiple organ systems. This can be considered a multiple organ failure that involves the heart, lungs, kidneys, the immune systems, and other organ systems. Progressive fibrosis of the liver and subsequent metabolic impairment leads to a systemic and splanchnic arteriolar vasodilatation. This affects both the haemodynamic and functional homeostasis of many organs and largely determines the course of the disease. With the progression of the disease, the circulation becomes hyperdynamic with cardiac, pulmonary as well as renal consequences for dysfunction and reduced survival. Infections and a changed cardiac function known as cirrhotic cardiomyopathy may be involved in further aggravation of other complications such as renal failure precipitating the hepatorenal syndrome. Patients with end-stage liver disease and related complications as for example the hepatopulmonary syndrome can only radically be treated by liver transplantation. As a bridge to this treatment, knowledge on the mechanisms of the pathophysiology of complications is essential for the choice of vasoactive drugs, antibiotics, drugs with specific effects on fibrogenesis and inflammation, and drugs that target specific receptors.

Monitoring and managing hepatic disease in anaesthesia

Patients with liver disease have multisystem organ dysfunction that leads to physiological perturbations ranging from hyperbilirubinaemia of no clinical consequence to severe coagulopathy and metabolic disarray. Patient-specific risk factors, clinical scoring systems, and surgical procedures stratify perioperative risk for these patients. The anaesthetic management of patients with hepatic dysfunction involves consideration of impaired drug metabolism, hyperdynamic circulation, perioperative hypoxaemia, bleeding, thrombosis, and hepatic encephalopathy.

Echocardiography for the detection of portopulmonary hypertension in liver transplant candidates: an analysis of cutoff values

Portopulmonary hypertension (POPH), a complication of chronic liver disease, may be a contraindication to liver transplantation (LT) because of the elevated risk of peritransplant and posttransplant morbidity and mortality. Because POPH is frequently asymptomatic, screening with echocardiography is recommended. The only reliable technique, however, for diagnosing POPH is right heart catheterization (RHC). The aims of this study were to evaluate the current estimated systolic pulmonary artery pressure (sPAP) cutoff value of 30 mm Hg and to determine a better cutoff value. One hundred fifty-two patients underwent pretransplant echocardiography between January 2005 and December 2010. These echocardiographic results were compared with pulmonary artery pressures measured during the pretransplant workup or at the beginning of the transplantation procedure (both by catheterization). With a cutoff value of 30 mm Hg, 74 of the 152 patients met the criteria for POPH on echocardiography, although the diagnosis was confirmed in only 7 patients during catheterization; this resulted in a specificity of 54%. It would have been more accurate to use a cutoff value of 38 mm Hg, which had a maximal specificity of 82% and, at the same time, guaranteed a sensitivity and negative predictive value of 100%. With the incorporation of the presence or absence of right ventricular dilatation, the specificity even increased to 93% for this new cutoff value. In conclusion, the prevalence of POPH was 4.6% among LT candidates in this study. We can recommend that LT candidates with an sPAP > 38 mm Hg should be referred for RHC. With the cutoff value increased from 30 to 38 mm Hg, the number of patients undergoing invasive RHC during their evaluation could be safely reduced.

Pulmonary vascular complications in portal hypertension and liver disease: a concise review

Chronic liver disease and/or portal hypertension may be associated with one of the two pulmonary vascular complications: portopulmonary hypertension and hepatopulmonary syndrome. These pulmonary vascular disorders are notoriously underdiagnosed; however, they have a substantial negative impact on survival and require special attention in order to understand their diagnostic approach and to select the best therapeutic options. Portopulmonary hypertension 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. On the other hand, abnormal intrapulmonary vascular dilations, profound hypoxemia, and a wide alveolar-arterial gradient are the hallmarks of the hepatopulmonary syndrome, resulting in difficult-to-treat hypoxemia. The aim of this review is to summarize the latest pathophysiologic concepts, diagnostic approach, therapy, and prognosis of portopulmonary hypertension and hepatopulmonary syndrome, as well as to discuss the role of liver transplantation as a definitive therapy in selected patients with these conditions.

The wound-healing response and upregulated embryonic mechanisms: brothers-in-arms forever

The cutaneous wound-healing reaction occurs in overlapping but inter-related phases, which ultimately result in fibrosis. The pathophysiological mechanisms involved in fibrotic diseases, including organ-related and even systemic diseases, such as systemic sclerosis, could represent the successive systemic upregulation of extraembryonic-like phenotypes, that is, amniotic and vitelline phenotypes. These two extraembryonic-like phenotypes act on the injured tissue to induce a process similar to gastrulation, which occurs during the early phases of embryo development. The amniotic-like phenotype plays a leading role in the development of neurogenic responses with significant hydroelectrolytic alterations that essentially represent the development of open microcirculation within the injured tissue. In turn, through the overlapping expression of a vitelline-like phenotype, a bone marrow-related response is produced. Interstitial infiltration by molecular and cellular mediators contributed by amniotic- and vitelline-like functions provides the functional and metabolic autonomy needed for inducing new tissue formation through mechanisms similar to those that act in gastrulation during the early phases of embryonic development. Thus, while a new tissue is formed, it quickly evolves into fibrotic tissue because of premature senescence. Mechanisms related to extraembryonic-like functions have been suggested in the following physiological and pathological processes: embryonic development; wound-healing reactions occurring during adult life; and senescence. The existence of this sort of basic self-organizing fractal-like functional pattern is an essential characteristic of our way of life.