Sildenafil Effect on Digital Ulcer Healing in sClerodErma SEDUCE STUDY

Inclusion Criteria: * Patient with systemic sclerosis (ScS) according to the classification criteria of the American College of Rheumatology or of "LeRoy" and "Medsger". * ScS patient with at least one ongoing ischaemic hand digital ulcer at baseline (see below the eligibility conditions of a digital ulcer). * Patient must have provided written informed consent prior to enrolment. Patient agrees to come to the follow up visits inside the protocol specified range. * Relative to each DU: DU must be beyond the proximal interphalangeal joint, on finger surface, of ischemic origin according to the physician, and not over subcutaneous calcifications or bone relief. Exclusion Criteria: * PAH requiring PDE5 inhibitors or prostacyclin history of stroke, myocardial infarction or life threatening arrhythmia within the last 6 months * severe cardiac failure (NYHA IV) or unstable angina within the last 6 months. * hereditary degenerative retinal disorders non-arteritic anterior ischemic optic neuropathy or untreated proliferative diabetic retinopathy * uncontrolled diabetes mellitus * Patient with known severe lung obstructive disease (FEV1\<70% on last available pulmonary function tests). * severe hepatic impairment * Patient with known impairment of renal function (serum creatinine \> 2.5 ULN). * Patient with severe malabsorption or any severe organ failure (e.g., lung, kidney) or any life-threatening condition. * Patient who has had surgical sympathectomy performed in the previous 1…