Letter to the Editor Correlation between intrarenal arterial stiffness and exercise tolerance in systemic sclerosis patients without renal and cardiopulmonary impairment: The role of the microvascular damage Antonietta Gigante a, ⁎, Antonella Romaniello b , Damiano Magrì b , Matteo Bonini c , Biagio Barbano a , Liborio Sardo a , Silvia Quarta a , Maria Anna Digiulio a , Marcello Di Paolo c , Rosario Cianci a , Paolo Palange c , Antonio Amoroso a , Edoardo Rosato a a Sapienza University of Rome, Department of Clinical Medicine, Clinical Immunology Unit-Scleroderma Center, Italy b Sapienza University of Rome, Department of Clinical and Molecular Medicine, Cardiology Unit, Italy c Sapienza University of Rome, Department of Public Health and Infectious Diseases, Italy article info Article history: Received 28 January 2015 Accepted 7 March 2015 Available online 10 March 2015 Keywords: Cardiopulmonary exercise test Systemic sclerosis Capillaroscopy Renal resistive index Doppler ultrasound Pulmonary vasculopathy 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 complica- tions 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 pul- monary 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. Thirty [23 females and 7 males; median age 50 years (20–55)] consecutive patients with SSc were enrolled in this study [5]. Mean duration of Raynaud's phenomenon (RP) and mean duration of disease were 11 (2–34) and 6.5 (1–21) years, respectively. Four- teen patients had limited and 16 had diffuse cutaneous SSc. All SSc patients underwent treatment with calcium channel blockers (nifedi- pine 30 mg/day). None of the patients were treated with immuno- suppressive agents. GFR was calculated with CKD-EPI equation [6]. Scleroderma patients with coronary artery disease, congestive heart failure, left ventricular dysfunction, valvular abnormalities and arrhythmias were not included in the study. Patients with pul- monary function abnormalities were not included either. Patients with diabetes mellitus, renal failure, hepatic or thyroid dysfunction and anemia were excluded. Patients were not taking β-blockers, an- tiarrhythmic drugs, ACE inhibitors or angiotensin receptor antago- nists. The subjects' written consent was obtained according to the Declaration of Helsinki and the study was approved by the Ethics Committee of the Sapienza University. All examined patients underwent clinical evaluation, electrocar- diography, transthoracic echocardiogram, baseline pulmonary func- tion tests (PFT). Renal Doppler ultrasound was performed using the same methods described in the previous study [4]. The mean refer- ence value for normal renal resistive index (RI) in adults is determi- nate to be 0.60 ± 0.10, with 0.70 as the upper limit of normal [7].A maximal symptom-limited CPET was performed on an electronically braked cycloergometer (Ergoline-800, Mortara, Bologna, Italy) ac- cording to the recommendations on the use of exercise testing in clinical practice [8]. Nailfold videocapillaroscopy (NVC) was classi- fied according to Cutolo et al.: early, active and late [9]. All data were expressed as median and range. The Mann–Whitney U-test or the Kruskal–Wallis was used to test differences between two in- dividual study groups. Spearman's rank order correlation coefficient (r) was used to test for an association between numerical variables. P-values b 0.05 were considered significant. P-values b 0.05 were considered significant. International Journal of Cardiology 185 (2015) 122–124 ⁎ Corresponding author at: Sapienza University of Rome, Department of Clinical Medicine-Clinical Immunology Unit Scleroderma Center, Viale dell'Università 37, 00185 Rome, Italy. E-mail address: antonietta_gigante@yahoo.it (A. Gigante). http://dx.doi.org/10.1016/j.ijcard.2015.03.089 0167-5273/© 2015 Elsevier Ireland Ltd. All rights reserved. Contents lists available at ScienceDirect International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard