Background: Previous studies on pulmonary hypertension (PH) in systemic sclerosis and related disorders used differing patient populations, and defined PH according to different criteria. We have attempted to determine the prevalence and cause of PH in these disorders using a mainly noninvasive cardiopulmonary evaluation.
Patients and methods: One-hundred thirty-five Japanese patients with systemic sclerosis and related disorders were divided into proximal and distal scleroderma groups, with or without overlapping features of systemic lupus erythematosus (SLE) and polymyositis. They underwent multiple cardiopulmonary tests, including chest radiography, pulmonary function tests, and echocardiography to screen for pulmonary fibrosis and PH.
Results: The pulmonary artery systolic pressure was estimated by Doppler echocardiography in 80 patients (59%). PH (systolic pressure ≥40 mm Hg) was diagnosed in 28 patients by the Doppler method and in two patients by right heart catheterization (mean pressure ≥20 mm Hg). Doppler-estimated pulmonary artery pressures were significantly higher in patients with proximal scleroderma (p<0.05), and in those with an SLE/polymyositis overlap (p<0.01). The FVC was significantly reduced in the proximal scleroderma group (p<0.0005), but not in the overlap group. PH was attributable to pulmonary fibrosis in nine patients who had proximal scleroderma without overlap. Pulmonary arteriopathy was the probable cause of PH in seven patients with overlap and in four patients who had proximal scleroderma without overlap.
Conclusions: These findings suggest that proximal scleroderma predisposes patients to PH mainly because of pulmonary fibrosis, but occasionally because of pulmonary arteriopathy. An overlap of SLE/polymyositis predisposes patients to PH due to the occurrence of arteriopathy.