Portopulmonary hypertension and hepatopulmonary syndrome: a clinician-oriented overview

Abstract

Liver disease and portal hypertension can be associated with pulmonary vascular complications, including portopulmonary hypertension (POPH), characterised by an elevated mean pulmonary artery pressure secondary to an increased pulmonary vascular resistance, and hepatopulmonary syndrome (HPS), characterised by hypoxaemia due to pulmonary vasodilatation and shunting. Although clear diagnostic guidelines exist for both conditions on the basis of echocardiography, right heart catheterisation and arterial blood gases, there is considerable variation between centres regarding diagnosis and management of these conditions. Awareness of evaluation and management algorithms for POPH and HPS are critical for optimisation of outcomes in patients with these conditions. Key aspects of management of POPH and HPS include identification of patients likely to benefit from liver transplantation (LTx) and management before and after LTx. Although both disorders may improve after LTx, severe forms of POPH represent a contraindication to LTx. Novel approaches to the treatment of POPH and HPS offer new management options that may expand the pool of transplantable patients and improve overall outcomes.

Figure 1.

Algorithm for the diagnosis and treatment of portopulmonary hypertension (POPH). All pressure determinations are expressed in mmHg. LT: liver transplant; RHC: right heart catheterisation; RVSP: right ventricle systolic pressure; P_pa: pulmonary artery pressure; P_pcw: pulmonary capillary wedge pressure; PAH: pulmonary arterial hypertension; PVR: pulmonary vascular resistance; TPG: transpulmonary gradient; TTE: transthoracic echocardiogram. ^#: Some centres report the pulmonary artery systolic pressure, which is equivalent to RVSP in the absence of right ventricle outflow obstruction; ^¶: the presence of signs of right ventricular strain would favour performing RHC; ⁺: alternative causes of pulmonary hypertension need to be ruled out on a case-by-case basis.

Figure 2.

Algorithm for the diagnosis and treatment of hepatopulmonary syndrome (HPS). All arterial blood gas (ABG) parameters are expressed in mmHg. P_A–a,O2: alveolar–arterial oxygen difference for the partial pressure of oxygen; CE-TTE: contrast-enhanced transthoracic echocardiogram; LT: liver transplant; MAA: ^99mTc radiolabelled macro-aggregated albumin scan; P_a,O2: arterial oxygen tension. ^#: if doubt exists regarding an atrial septal defect, trans-oesophagseal echocardiography is recommended; ^¶: pulmonary function tests and chest radiographs or computed tomography scans as appropriate; ⁺: determination of orthodeoxia is recommended where available; ^§: MAA is also useful in the absence of lung disease to quantify the intrapulmonary shunt and for prognostication.