Pulmonary hypertension in systemic lupus erythematosus: pulmonary thromboembolism is the leading cause.

BACKGROUND: Pulmonary hypertension (PH) is a life-threatening complication of systemic lupus erythematosus (SLE). Pulmonary hypertension in SLE has a variety of causes. Diagnosing early and defining the cause of PH accurately can provide better clinical outcome in SLE. We investigated the causes and characteristics of PH in patients with SLE. METHODS: One hundred twenty-one patients with SLE who had a visit in a 6-month period were assessed retrospectively. Patients who ever had a systolic pulmonary arterial pressure of 40 mm Hg or greater by Doppler echocardiography were considered to have PH. RESULTS: Among 122 patients, 65 had echocardiography for some reason, and 10 (8.2%) were diagnosed as having PH by echocardiographic examination. This number reduced to 9 (7.4%) when we excluded the patient with normal pulmonary artery pressure at right heart catheterization. Causes of PH were as follows: thromboembolic events in 4 patients (44.4%) (2 of them had chronic thromboembolic PH), left-sided heart disease in 2 patients (22.2%), pulmonary arterial hypertension in 1 patient (11.1%), high cardiac output state in 1 patient (11.1%), and transient elevation of systolic pulmonary artery pressure in 1 patient (11.1%) who had a history of venous thromboembolism. Venous thromboembolic disease was significantly higher in patients with SLE with PH in comparison to patients with SLE without PH (7 patients [6.3%] vs 5 patients [50.0%]; P = 0.001). All patients improved clinically during their short-term follow-up. CONCLUSIONS: Patients with SLE are at increased risk for PH. This study highlights the complexity of the differential diagnosis of PH in patients with SLE once again and emphasizes the importance of pulmonary thromboembolism as a cause of PH. One should investigate patients with SLE with unexplained symptoms and/or signs related to PH for possible treatable causes.