FRI0314 SENSITIVITY TO CHANGE AND RESPONSIVENESS TO TREATMENT OF RENAL RESISTIVE INDEX (IRR) IN SYSTEMIC SCLEROSIS (SSC)

Background RRI may identify any problem with the blood flow in the renal artery and in the parenchyma. It was shown to be increased in SSc patients and being in relationship with both vascular and fibrotic SSc-related manifestations. Objectives: to test sensitivity to change and responsiveness to treatment of RRI in SSc. Methods: patients fulfilling the 2013 ACR/EULAR classification creteria for SSc were enrolled from two SSc-care units, if RRI was determined at least twice since being diagnosed. Data regarding SSc clinical manifestations, instrumental and laboratory evaluation for renal, cardiac and cardiovascular involvement, as well as ongoing immunosuppressive and vasoactive/vasodilating treatment, were collected both at baseline and follow-up RRI measurements. Results 230 patients [aged 57 (48-67) years, 12.6% males] were enrolled in the study, with baseline RRI value of 0.68 (IQR 0.07). In a mean 3.4 years follow-up, RRI showed a median change (ΔRRI) of +0.02 (IQR 0.05). ΔRRI was significantly correlated with ΔsPAP (R=0.173, p=0.023) and it was significantly higher in patient with new onset of pulmonary arterial hypertension (0.08 ± 0.02 vs 0.03 ± 0.05; p=0.038). On Cox univariate regression analysis, time from disease onset, ΔssPAP and ΔRRI predicted new PAH, while ΔsPAP was the only independent predictors at multivariate regression analysis. Regarding treatment, Sildenafil exposure determined a significantly lower increase in ΔRRI, with a progressive long-term effect. Conversely, CCBs and Iloprost treated patients showed a significantly higher increase of ΔRRI, which was determined by a higher DU burden. No difference was seen when immunosuppressive treatment was evaluated. Conclusion RRI is sensitive to change and reflects, in particular, the worsening of cardio-pulmonary vascular involvement (increase in ΔsPAP and new PAH onset). Moreover, it shows a possible protective effect of Sildenafil in reducing pulmonary vasculature manifestations. Disclosure of Interests Cosimo Bruni: None declared, Edoardo Rosato: None declared, Antonietta Gigante: None declared, Vanessa Maestripieri: None declared, Giulia Tesei: None declared, Marco Chiostri: None declared, Gemma Lepri: None declared, Silvia Bellando Randone: None declared, Serena Guiducci: None declared, Sergio Castellani: None declared, Maria Boddi: None declared, Marco Matucci-Cerinic Grant/research support from: Actelion, MSD, Pfizer, BMS, Chemomab, Sanipedia, Speakers bureau: Actelion, BMS; MSD, Janssen