EDN1 and thrombotic thrombocytopenic purpura: Regarding disease severity and outcome prognosis, ADAMTS13 qualities, as well as non-ADAMTS13 indices (troponin [12], endothelial activation with big endothelin-1 and syndecan-1 [53,54], and Glasgow coma scale [12]) have been proposed as prognostic risk factors for TTP outcome [11].