Lack of association between six-minute walk distance and pulmonary artery pressure in patients with systemic sclerosis and cardiopulmonary symptoms

The six-minute walk test (6MWT) is a non-invasive test used to assess cardiopulmonary performance. The aim of this study was to evaluate the performance of 6MWT in predicting pulmonary artery hypertension (PAH) and interstitial lung disease in patients with systemic sclerosis (SSc) and cardiopulmonary symptoms. Sixty-three patients with SSc who had dyspnea, cough, chest pain and syncope underwent 6MWT, high-resolution computed tomography (HRCT), spirometry, body plethysmography and single breath carbon monoxide diffusion measurement. There were no significant differences in mean 6MWD between patients with diffuse SSc compared with limited disease, patients with no parenchymal involvement compared with patients with parenchymal involvement <20% and≥20% in HRCT, and patients with PAP ≥25 mm Hg compared with patents with PAP <25 mm Hg. No significant relationship was found between 6MWD and age, mean PAP, forced expiratory volume, forced vital capacity and diffusing capacity of the lungs for carbon monoxide. The present study showed that in patients with SSc and cardiopulmonary symptoms, 6MVT does not help to predict PAH and parenchymal lung involvement.