THERMES ET VEINES: Spa for Prevention of Leg Ulcers

Inclusion Criteria: * Both sexes, more than 18 years old patients with a phlebological indication of spa treatment, with advanced chronic venous insufficiency, class C4a, or b or C5 of CEAP classification (leg ulcers must be healed since 3 months at least) * Available for a spa treatment during 18 days (immediate or late spa)and a follow-up period of 18 months * Voluntary to participate to the study,informed consent form signed after appropriate information * Affiliation to the social security system or equivalent Exclusion Criteria: * Pregnancy, parturient or breast feeding * No psychiatric illness or social situation that would preclude study compliance * Leg ulcer in progress * Leg ulcer healed for less than 3 months * Refusal to consent * Refusal of spa treatment * Contra-indication of spa treatment(cancer in progress, psychiatric disorders, immunodeficiency) * Arteriopathy of lower limb with an Ankle Brachial Pressure Index (ABPI)\< 0.7, symptomatic neuropathy, erysipelas within 5 years prior to inclusion * Surgical or endovascular treatment of the venous disease planned during the first year or during the six months prior to inclusion * No previous phlebological spa treatment within 6 months prior to inclusion