Exercise limitation in stable systemic sclerosis: insights from cardiopulmonary exercise test

Rationale: Dyspnea and exercise limitation are common symptoms in Systemic Sclerosis (SSc) patients. Multiorgan involvement and disease activity could lead patients to different clinical complications and affect prognosis. Aim of this study was to explore the role of cardiopulmonary exercise test (CPET) in the evaluation of exercise limitation and in the characterization of specific phenotypes of organ involvement in SSc patients. Methods: 24 consecutive patients (23 women, 51.3 ± 2.0 mean age) diagnosed with clinically stable SSc (EULAR 2013) underwent resting echocardiography and maximal symptom-limited incremental CPET. Patients were categorized into three groups: A (interstitial lung disease on CT scan), B (pulmonary vascular diesase), C (left ventricular dysfunction). Results were compared with those of 23 healthy controls and among SSc groups. Results: Compared to controls, SSc patients exhibited a significant reduction in functional capacity, ventilatory limitation and a higher estimated pulmonary pressure at echocardiography. Group A (3 patients) exhibited reduced ventilation, lower VO2max, higher PetCO2, and a worse oxygen uptake efficiency slope. Group B (6 patients) was charaterized by higher VE/VCO2 slope, reduced exercise capacity and a peculiar breathing pattern with the presence of exercise oscillatory ventilation. Group C (15 patients) showed lower ventilation, VO2max and VO2/work slope. Conclusion: CPET can unmask early exercise limitation and can be useful in the identification of different clinical phenotypes in SSc patients.