Correlation between intrarenal arterial stiffness and exercise tolerance in systemic sclerosis patients without renal and cardiopulmonary impairment: The role of the microvascular damage.

Systemic sclerosis (SSc) is a connective tissue disease characterized by endothelial dysfunction, microvascular damage and fibrosis of the skin and internal organs. Many of the severe internal organ complications of SSc are vascular, including pulmonary arterial hypertension (PAH) and scleroderma renal crisis [1]. Pulmonary vasculopathy (PV) is early detected in SSc patients without symptoms of pulmonary involvement. At this initial stage PV is characterized by impairment of blood flow during exercise. A reduced exercise tolerance, investigated by cardiopulmonary exercise test (CPET), has been already found in SSc patients without evidence of pulmonary and cardiac involvement [2]. In the course of SSc several manifestations of renal involvement are due to intrarenal vascular damage. In SSc patients without renal involvement, intrarenal arterial stiffness is increased and it correlates with digital microvascular damage [3], reduction of glomerular filtration rate (GFR) and autonomic dysfunction [4]. The aim of the study is to assess intrarenal arterial stiffness by Doppler ultrasound and examine the correlation with CPET in patients without renal, pulmonary and cardiac involvement.