Lo START2 PORTUGAL is an independent observational prospective cohort, multicenter study, on the history of patients treated with anticoagulant/antithrombotic drugs. The aims of the study are to provide a better evaluation of efficacy and safety of different treatment options, and to improve our understanding of the risks/benefits of the various drugs by recording and analyzing data from patients observed in real life. The study has an exclusively observational purpose in order to be the starting point for collaborative clinical studies, enabling their planning and execution; it is not aimed to influence the treatment of the individual patients included in the study.