Pulmonary arterial hypertension (PAH) is a pathophysiological condition characterized by
increased pulmonary vascular resistance (PVR), initially due to abnormal pulmonary vasoconstriction
in response to endothelial injury. Recent studies confirmed the key role of endothelin (ET)-1 in the
vasoconstriction and remodeling of pulmonary microcirculation during PAH. In responders patients,
classical treatments for PAH are prostanoids, phosphodiesterase (PDE)-5 inhibitors and endothelin receptor
antagonists (ERAs), which target prostaglandin I2, nitric oxide and endothelin pathways, respectively.
Randomised, placebo-controlled trials have shown that ERAs improves haemodynamic parameters of the pulmonary
circulation, functional capacity and clinical outcome in patients affected by PAH. Here, we will review the definition,
classification and pathophysiology of PH. Furthermore, we will provide an up-to-date overview of currently recommended
diagnostic and therapeutic work-up in PAH.