Introduction: Pulmonary arterial hypertension (PAH) is one of the most severe complications of connective tissue diseases. PAH is defined by mean arterial pulmonary pressure > 25 mmHg at rest (or 30 mmHg during exercise) during right heart catheterisation.
State of the art: About 10% of cases of PAH are related to connective tissue diseases. PAH may be observed in any of the connective tissue diseases; it is mostly encountered in systemic sclerosis (prevalence estimated to 8%), and is more frequent in the limited form of the disease with anticentromeres antibodies, in the presence of Raynaud's phenomenon, of antinuclear antibodies, decreased CO diffusion capacity, and during the perimenopausal period. Histopathological lesions are similar to that of idiopathic PAH (with plexogenic lesions being more rare); mutations have not been described. Venous thromboembolic disease (especially in lupus) and hypoxemia related to pulmonary fibrosis should be investigated. Screening for PAH is recommended in systemic sclerosis (by echocardiography every year and in case of dyspnea). Few clinical trials have been conducted specifically in PAH related to connective tissue diseases, therefore the treatment approach is similar to that of idiopathic PAH, with a poorer prognosis, including treatment with bosentan, epoprostenol and other prostacyclin analogs, and sildenafil. Immunosuppressive therapy may occasionally improve PAH in patients with systemic erythematosus lupus or mixed connective tissue disease.
Perspectives: Respective indications of drugs and treatment associations need to be precised.
Conclusion: The availability of efficacious treatments of PAH justifies its screening and early diagnosis in connective tissue diseases.