Background and purpose: Pulmonary arterial hypertension (PAH), a serious complication of autoimmune diseases, has rarely been reported in Taiwan.
Methods: Nineteen patients with various autoimmune diseases diagnosed with PAH at Taipei Veterans General Hospital from 2002 to 2004 were enrolled; the underlying autoimmune diseases included systemic lupus erythematosus (n = 6), primary Sjögren's syndrome (n = 5), systemic sclerosis (n = 4), adult-onset Still's disease (n = 2), and mixed connective tissue disease (n = 2). The characteristic manifestations of underlying autoimmune diseases and the clinical features of PAH were analyzed.
Results: There were 16 female and 3 male patients. The median age at onset of PAH was 44 years and the mean right ventricular systolic pressure (RVSP) was 67.9 mm Hg. Patients without pneumonitis had a significantly higher RVSP value than those with pneumonitis (77.5 +/- 24.3 vs 54.8 +/- 18.4 mm Hg, p=0.041). Four out of 7 patients (57.1%) with RVSP >or=80 mm Hg and 1 out of 12 patients (8.3%) with RVSP <80 mm Hg died. In all of the 19 patients, the severity of RVSP was significantly correlated with serum uric acid (UA) level (r = 0.686, p=0.001). Among the PAH patients without pneumonitis, the severity of RVSP inversely correlated with the diffusion capacity of the lung for carbon monoxide (DLCO) [r = -0.856, p=0.003]. The characteristic manifestations of underlying autoimmune diseases included a high incidence of Raynaud's phenomenon (15/19, 78.9%), a high titer of antinuclear antibody (13/17, 76.5%), positive anti-ribonucleoprotein antibody (8/15, 53.3%), hypergammaglobulinemia (15/19, 78.9%), hyperuricemia (13/19, 68.4%), and less renal involvement.
Conclusions: PAH in autoimmune diseases could be potentially fatal with characteristic manifestations. Moreover, RVSP correlated directly with serum UA level and inversely with DLCO.