Inclusion Criteria:  adult patients non-treated immune thrombocytopenia or immune thrombocytopenia with stable treatment (at least 1 month) treated with aspirin daily for a cardiovascular disease; stable platelet count < 100 x 109/L at least one month following an arterial thrombosis no other antiplatelet drug and anticoagulant female patient with childbearing potential must have acceptable method of birth control affiliated or benefiting from public health insurance  Exclusion Criteria:  opposition to participate adults under guardianship or other legal protection deprived of their liberty by judicial or administrative decision pregnancy or breastfeeding