Konstantinos Tselios, Dafna D Gladman, Murray B Urowitz

Systemic lupus erythematosus (SLE) is characterized by the second highest prevalence of pulmonary arterial hypertension (PAH), after systemic sclerosis, among the connective tissue diseases. SLE-associated PAH is hemodynamically defined by increased mean pulmonary artery pressure at rest (≥25 mmHg) with normal pulmonary capillary wedge pressure (≤15 mmHg) and increased pulmonary vascular resistance. Estimated prevalence ranges from 0.5% to 17.5% depending on the diagnostic method used and the threshold of right ventricular systolic pressure in studies using transthoracic echocardiogram. Its pathogenesis is multifactorial with vasoconstriction, due to imbalance of vasoactive mediators, leading to hypoxia and impaired vascular remodeling, collagen deposition, and thrombosis of the pulmonary circulation. Multiple predictive factors have been recognized, such as Raynaud's phenomenon, pleuritis, pericarditis, anti-ribonuclear protein, and antiphospholipid antibodies. Secure diagnosis is based on right heart catheterization, although transthoracic echocardiogram has been shown to be reliable for patient screening and follow-up. Data on treatment mostly come from uncontrolled observational studies and consist of immunosuppressive drugs, mainly corticosteroids and cyclophosphamide, as well as PAH-targeted approaches with endothelin receptor antagonists (bosentan), phosphodiesterase type 5 inhibitors (sildenafil), and vasodilators (epoprostenol). Prognosis is significantly affected, with 1- and 5-year survival estimated at 88% and 68%, respectively.