Consenting patients with end-stage heart failure that are implanted with/candidates for implant of a short-term/durable mechanical circulatory support device (e.g.: percutaneous microaxial pumps (Impella), extracorporeal membrane oxygenator (ECMO), Ventricular Assist Device (VAD) will be enrolled in the study. Aim of the study is to evaluate the patients' haemostatic and coagulation profile, how it interacts with the support device as well as the effect of antithrombotic drugs. From these data, it will be possible to derive the mechanisms triggering post-implant thromboembolic/hemorrhagic complications and to identify potential therapeutic targets.