Portopulmonary Hypertension

Ambrisentan in portopulmonary hypertension: A multicenter, open-label trial

BACKGROUND

Ambrisentan has shown effectiveness in the treatment of Group 1 pulmonary arterial hypertension (PAH). Although portopulmonary hypertension (PoPH) is a subset of Group 1 PAH, few clinical trials have been testing PAH therapies in patients with PoPH. The objective of this study is to evaluate the efficacy and safety of ambrisentan in PoPH.

METHODS

This study is a prospective, multicenter, open-label trial in which treatment-naive patients with PoPH with Child-Pugh class A/B were administered with ambrisentan for 24 weeks, followed by a long-term extension (24-28 weeks). The primary end-points were change in pulmonary vascular resistance (PVR) and 6-minutes walk distance (6MWD) at 24 weeks, whereas secondary end-points included safety, World Health Organization (WHO) functional class (FC) and echocardiographic assessments.

RESULTS

Of the 31 patients, 23 finished 24 weeks of ambrisentan therapy and 19 finished the extension. PVR decreased significantly (mean ± SD) (7.1 ± 5 vs 3.8 ± 1.8 Wood units, p < 0.001), whereas 6MWD remained unchanged (314 ± 94 vs 336 ± 108 m). Other hemodynamic parameters such as right atrial pressure (13 ± 8 vs 9 ± 4 mm Hg, p < 0.05), mean pulmonary arterial pressure (46 ± 13 vs. 38 ± 8 mm Hg, p < 0.01), cardiac index (2.6 ± 0.6 vs. 3.5 ± 0.7 liter/min/m², p < 0.001) showed improvement, whereas pulmonary capillary wedge pressure remained unchanged. Of the 22 patients with WHO FC assessments at baseline and 24 weeks, WHO FC improved significantly (p = 0.005). Most frequent drug-related adverse events were edema (38.7%) and headache (22.5%). One episode of leg edema resulted into the permanent discontinuation of ambrisentan.

CONCLUSIONS

Ambrisentan monotherapy in PoPH improves hemodynamics and FC at 24 weeks; however, it did not show any improvement in 6MWD. These preliminary outcomes should be interpreted with caution (Clinicaltrials.Gov:NCT01224210).

Morphologic and Functional Changes in Right-Sided Cardiac Chambers in Patients With Chronic Liver Disease and Normal Pulmonary Artery Pressure

OBJECTIVES

To investigate the effects of chronic liver disease (CLD) on the structural and functional characteristics of right-sided heart chambers in patients with normal pulmonary artery pressure.

METHODS

Fifty-one patients with known CLD but without pulmonary hypertension or other cardiovascular conditions were consecutively enrolled, along with 25 age- and sex-matched participants. Patients with CLD were classified according to the Model of End-Stage Liver Disease score and Child-Pugh classification. Right ventricular (RV) and right atrial (RA) dimensions, indices of RV systolic/diastolic function, and myocardial strain were measured by standard echocardiographic methods.

RESULTS

Patients in the study group had similar RV end-diastolic, end-systolic, and RA dimensions compared to controls. Similarly, neither the conventional indices of RV systolic/diastolic function nor the strain imaging findings were different between groups (P > .05). Only RV free wall thickness was significantly higher in the study group (mean ± SD, 4.15 ± 0.64 versus 3.75 ± 0.37 mm; P < .001). Right ventricular end-diastolic diameter (P = .018; r = 0.334) and RA area (P = .017; r = 0.335) had a significant correlation with RV free wall thickness in patients with CLD. Patients treated with beta blockers were found to have a significant reduction in mean RV free wall strain compared to patients who did not receive beta blocker treatment (-20.37 ± 6.6 versus -24.07 ± 6.52; P = .04).

CONCLUSIONS

Patients with CLD had increased RV free wall thickness despite normal systolic pulmonary pressure, presumably secondary to cirrhotic cardiomyopathy. In the absence of pulmonary hypertension, however, cirrhotic cardiomyopathy did not cause impaired RV systolic or diastolic function.

"Porto-pulmonary hypertension: a comprehensive review"

Porto-pulmonary hypertension (PoPH) is a rare but threatening vasculopathy, defined by the presence of pulmonary arterial hypertension (PAH) in the setting of portal hypertension. Although most commonly observed in cirrhotic patients, those with non-cirrhotic portal hypertension are also at risk of developing it. Little is known about the mechanisms by which PAH develop in patients with portal hypertension, but genetic factors, pulmonary vascular wall shear stress, and a dysregulation of vasoactive, proliferative and inflammatory mediators might be involved. PoPH is estimated to occur in 3 to 10% of patients with end-stage liver disease, although its frequency is not related to the severity of liver dysfunction or the degree of portal hypertension. Moderate-to-severe PoPH portends an extremely poor prognosis. Presentation is highly variable, therefore a high index of suspicion is required to establish the diagnosis. PoPH should be screened by transthoracic echocardiography (TTE) in cirrhotic patients presenting with dyspnoea as well as in all patients being evaluated for liver transplantation (LT) regardless of their symptoms. If TTE shows elevated pulmonary pressures, patients should undergo right heart catheterisation, which is required for the definitive diagnosis of PoPH. Without LT, the overall 5-year mortality in PoPH patients is 70%, but it should not be considered an indication for LT. Moderate-to-severe PoPH contraindicates LT, since it is associated with a prohibitively increased intra and postoperative mortality. However, there is now evidence supporting the use of PAH-specific therapies pre-LT in order to improve pulmonary haemodynamic measurements, so the procedure can then be performed with significantly lower risks.