Prospects for improving outcomes in systemic sclerosis-related pulmonary hypertension

Pulmonary arterial hypertension (PAH) is a leading cause of morbidity and mortality in patients with systemic sclerosis (SSc). Approximately one in 10 will develop PAH during their lifetime. These patients have a worse prognosis than those with PAH due to other causes. The most common clinical feature of SSc-PAH in the early stages is non-specific exercise intolerance that can be erroneously attributed to other manifestations of SSc. Screening provides an opportunity for early identification of SSc-PAH and prompt initiation of therapies with the potential to improve quality of life and survival. International guidelines recommend annual transthoracic Doppler echocardiography (TTE), but TTE has limitations. The tricuspid regurgitant jet required for estimating the systolic pulmonary artery pressure is absent in up to 39% of patients, including a proportion with PAH. This has prompted a move to new screening algorithms that are less dependent on TTE. Not all pulmonary hypertension (PH) in patients with SSc is PAH. Other causes include PH secondary to left heart disease, interstitial lung disease-related PH, chronic thromboembolic PH and pulmonary veno-occlusive disease. With the advent of evidence-based therapies, including newer agents such as macitentan, riociguat and selexipag, the establishment of centres with expertise in PAH and the focus on early detection, there has been considerable improvement in survival. The role of anti-coagulation for SSc-PAH has been the subject of a recent meta-analysis of nine observational studies that suggests it may confer a survival benefit, but to date, there have been no randomised controlled trials to confirm this.