Pulmonary arterial hypertension in connective tissue diseases.

Pulmonary arterial hypertension (PAH) may complicate diverse connective tissue diseases (CTDs). Approximately 10% of patients with systemic sclerosis develop PAH, the prevalence being much lower in other CTDs. However, PAH is an important contributor to morbidity and mortality in all forms of CTD. Despite similarities in presentation, hemodynamic perturbations, and pathogenesis, patients with CTD-associated PAH (CTD-PAH) usually have a poorer response to PAH-specific medications and poorer prognosis than patients with idiopathic PAH (IPAH). Select patients with CTD-PAH may be candidates for lung transplantation, but results are less favorable than for IPAH because of comorbidities and complications specifically associated with CTD.