START-EVENT is a prospective, observational, international, multi-center study promoted through the Scientific and Standardization Committee (SSC) Control of Anticoagulation of the International Society of Thrombosis and Haemostasis, The purpose is to collect clinical data that are useful to analyze and to identify the best way to treat acute bleeding or thrombotic events that occur during anticoagulation with DOACs and to describe clinical outcomes both in the short-term and after a 6-month follow-up.