Current management of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a vascular disease of unknown aetiology, characterised by an abnormal thickening of the arterial wall that is responsible for an increase in pulmonary vascular resistance. The haemodynamic consequence of PAH is an increased afterload for the right ventricle and, eventually, right heart failure. When untreated, PAH has a grim prognosis with a median survival of about 2 to 4 years from diagnosis. In the last 10 years new orally administered compounds have demonstrated clinical efficacy in controlled trials using various surrogate endpoints to survival. Although the disease remains without cure until now, the available phase III trials have allowed evidence-based recommendations for the medical management of these patients to be established. It appears, however, that none of the compounds from the three main therapeutic classes, endothelin receptor antagonists, agents acting on the nitric oxide-cyclic guanosine monophosphate pathway (including phosphodiesterase type 5 inhibitors and guanylate cyclase stimulator), and prostanoid receptor agonists are able alone to control disease progression in every patient. Therefore combination therapy with two or three drugs may be necessary in a significant number of patients in order to maintain patients in, or bring them to, a low risk profile. Several recent studies have now validated this approach for specific double or triple drug regimens. It remains, however, unclear whether an upfront combination is preferable to a sequential step-up approach based on clinical response. In addition, some specific combination therapies have failed to demonstrate superiority to single drug alone in randomised controlled trials. Besides PAH-specific treatment, the place of nonspecific pharmaceutical and nonpharmaceutical treatment has been also recently clarified.