SummaryImpaired platelet function is a major risk factor for peri-operative bleeding and transfusion. This prospective, observational study enrolled 101 consecutive patients undergoing elective cardiac surgery with cardiopulmonary bypass. Platelet function was assessed by two whole blood impedance aggregometers (ROTEM â platelet and Multiplate â ), using three different activators (arachidonic acid, adenosine diphosphate and thrombin receptor-activating peptide-6), at three peri-operative time points (before anaesthesia, after aortic declamping and 5-10 min after protamine administration). Platelet function was impaired over the time-course in all assays. Results after protamine administration demonstrated the best correlation with postoperative chest tube drainage. Patients with a chest tube drainage exceeding the 75th percentile of the entire study population, during the first 24 postoperative hours, were characterised to have excessive bleeding. Both devices provided similar predictability for postoperative chest tube drainage and red blood cell transfusion requirements. The latter was associated with the degree of platelet inhibition and the number of pathways inhibited determined respective cut-off values.

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Bleeding and thrombotic events are among the most common complications detected in patients with mechanical circulatory support (MCS). Herein, we reviewed the available evidence on the prevalence, etiology, and management of bleeding and thrombotic events in patients following MCS procedures, such as implantation of both intra- and paracorporeal devices that generate either pulsatile or nonpulsatile flow. Extracorporeal life support procedures providing support to the failing heart and lungs were also reviewed. Most bleeding and thromboembolic events occur despite appropriate hemostatic and anticoagulation management based on conventional coagulation laboratory parameters. Prevalence of bleeding events in this population ranges between 5 and 81%. Wide range in prevalence of bleeding reported in literature may be explained by different devices with different anticoagulation protocols being used, as well as different definitions of bleeding outcomes. Although bleeding events are more common than thromboembolic events, the consequences of thrombotic events are often detrimental. Management of bleeding events remains challenging and measures to prevent and treat bleeding events are often followed by thromboembolic events. Therefore, a personalized approach based on point-of-care hemostatic tests and adjusted to device type and patient comorbidities is therefore warranted. To provide advanced understanding of hemostatic disturbances during MCS, prospective trials focused on bleeding and thromboembolic events as primary endpoints should be conducted. Better understanding of the underlying pathophysiology and a shift towards a personalized approach based on functional point-of-care hemostatic properties assessment may provide more favorable clinical outcomes. This should, however, be coupled with further technological improvements providing better device surface hemocompatibility as interaction between blood and device surface affects the hemostatic equilibrium.