Cardiopulmonary exercise testing is an accurate tool for the diagnosis of pulmonary arterial hypertension in scleroderma related diseases

The early diagnosis of pulmonary arterial hypertension (PAH) is a major determinant of prognosis in patients affected by connective tissue diseases (CTDs) complicated by PAH. In the present paper we investigated the diagnostic accuracy of cardiopulmonary exercise testing (CPET) in this specific setting. We recorded clinical and laboratory data of 131 patients who underwent a CPET at a pulmonary hypertension clinic. Out of them, 112 (85.5%) had a diagnosis of CTDs; 8 (6.1%) received a diagnosis of CTDs-PAH and 11 (8.4%) were affected PH of different etiology. Among CPET parameters the following parameters showed the best diagnostic performance for PAH: peak volume of oxygen uptake (VO₂; AUC: 0.845, CI95% 0.767-0.904), ratio between ventilation and volume of exhaled carbon dioxide (VE/VCO₂ slope; AUC: 0.888, CI95%: 0.817-0.938) and end-tidal partial pressures (PetCO₂; AUC: 0.792, CI95%: 0.709-0.861). These parameters were comparable among CTDs-PAH and PH of different etiology. The diagnostic performance was even improved by creating a composite score which included all the three parameters identified. In conclusion, CPET is a very promising tool for the stratification of risk of PAH among CTDs patients; the use of composite measures may improve diagnostic performance.