Portopulmonary Hypertension: From Bench to Bedside

Abstract

Portopulmonary hypertension (PoPH) is defined as pulmonary arterial hypertension (PAH) associated with portal hypertension and is a subset of Group 1 pulmonary hypertension (PH). PoPH is a cause of significant morbidity and mortality in patients with portal hypertension with or without liver disease. Significant strides in elucidating the pathogenesis, effective screening algorithms, accurate diagnoses, and treatment options have been made in past 20 years. Survival of PoPH has remained poor compared to IPAH and other forms of PAH. Recently, the first randomized controlled trial was done in this patient population and showed promising results with PAH specific therapy. Despite positive effects on hemodynamics and functional outcomes, it is unclear whether PAH specific therapy has a beneficial effect on long term survival or transplant outcomes. In this review, we will discuss the epidemiology, pathophysiology, clinical and hemodynamic characteristics of PoPH. Additionally, this review will highlight the lacunae in our current management strategy, challenges faced and will provide direction to potentially useful futuristic management strategies.

Progressive dyspnoea in a patient with idiopathic non-cirrhotic portal hypertension

“…It can develop in patients with portal hypertension with or without concomitant liver disease, such as in this case of non-cirrhotic portal hypertension [3]. The histopathology is indistinguishable from other PAH subgroups and is characterised by intimal proliferation, smooth muscle hypertrophy and plexiform lesions [9,11]. However, the epidemiology and pathobiology are incompletely defined [9].…”

Portopulmonary hypertension: a patient with shortness of breath

“…Most patients are misdiagnosed for years, leading to a significant progression of their disease. Second, there are no guidelines, which lead to a high variability in medical management 5. Research is ongoing in this complex field, and we hope to see some improvements in patient care soon.…”

“…The increase in pulmonary pressure causes remodelling of the pulmonary vasculature which then leads to higher vasculature resistance 1. In patients with hyperdynamic circulations the increased cardiac output leads to an increase in the sheer stress placed on the pulmonary circulation 5. This additional stress results in an increase in pulmonary vascular resistance which then initiates a cascade of events, leading to vasoconstriction, pulmonary vascular remodelling and an increase in thrombi 6.…”

Cardiovascular risk stratification in the noncardiac solid organ transplant candidate

“…Screening for PoPH is important in LT candidates, as significant PoPH is a contraindication to LT and any degree of PoPH may affect pre and posttransplant survival [28,29]. Transthoracic echo can be used as an initial screening modality, with expert consensus that an RVSP > 45 mmHg or other findings consistent with PoPH and/or RV dysfunction should prompt referral for right heart catheterization [30]. Invasive hemodynamic findings of elevated mPAP (>20 mmHg) with a normal PCWP (<15 mmHg) in the presence of portal HTN (hepatic wedge to vein gradient > 5 mmHg) is diagnostic of PoPH.…”