Pulmonary Hypertension in Systemic Sclerosis

Abstract

The main cause of death in systemic sclerosis is interstitial lung disease, followed by pulmonary hypertension (PH). Pulmonary hypertension is the result of microvasculopathy which is caused by a disrupted healing process of endothelin damage and is featured by vasoconstriction, proliferation of arterial wall, inflammation, and fibrosis. Reclassification of pulmonary hypertension has led to five distinctive groups. In systemic sclerosis, patients may suffer from pulmonary artery hypertension (PAH, group 1), pulmonary hypertension due to interstitial lung disease (group 3), cardiac disease (group 2), and/ or thromboembolic pulmonary hypertension (group 4). Patients endure declining performance during exercise, but symptoms may be variable and nonspecific. Diagnosis is made by right heart catheterization. To select patients for this invasive procedure, several screening tools are discussed, including N-terminal pro-brain natriuretic peptide levels, uric acid levels, spirometry and diffusing capacity for carbon monoxide (DCLO), echocardiography (ECG), and the DETECT algorithm. Depending on features such as disease duration, presence of anti-centromere antibodies, and DCLO, three different flow charts for screening are presented. Based on pathophysiology, several medical treatments have been developed like prostanoids, endothelin receptor antagonists, phosphodiesterase-5 inhibitors, and stimulation of the nitric oxide pathway. Combination therapy as well as lung transplantation and supportive therapy is discussed.