A potential clinically relevant approach for establishing the optimal duration of Oral AntCoagulant Therapy (OAT) is that of predicting the individual risk for thrombotic recurrency after the index Deep Vein Thrombosis (DVT). Although the current scheme for establishing the duration of OAT is based on the nature of index DVT (idiopathic or provoked), some new data starting to select other parameters to optimize this decision. Recently, the use of D-dimer has been proven to be effective for selecting OAC duration; however, this investigation evaluated only patients with idiopathic DVT and, moreover, the use of D-dimer can not be easily handle by most of Institutions.