PLATelet Function Operating Room Monitoring

Preoperative platelet function is a known determinant of postoperative bleeding in cardiac surgery patients (1,2). Conversely, there is a lack of information with respect to postoperative platelet function and postoperative bleeding, and specific cut-off values have not been identified yet.

This study will verify the hypothesis that postoperative platelet function is associated with bleeding, and will test the ability of platelet function tests (PFTs) in predicting severe postoperative bleeding. Additional analyses linking platelet function to other preoperative and intraoperative conditions are planned.

Patients: Enrollment between February 2017 and January 2018. 800 consecutive adult cardiac surgery patients are considered based on our usual surgical activity. Exclusion criteria: unwillingness to participate, known congenital coagulopathy. Moderate/severe bleeding occurs in about 12% of our patient population. Considering a 15% dropout rate, there are about 80 predicted events. Power analysis: to build a predictive model, at least 60 events of moderate/severe bleeding are required. The study will be stopped at reaching (whatever comes first) 800 enrolled pts; 60 events; or 31st January 2018.

Methods: all the patients will receive a preoperative (in the operating room) PFT (ADPtest and TRAPtest) using the aggregometry Multiplate (Roche). The same test will be repeated after protamine administration at the end of CPB.

Definitions of bleeding: 12-hours chest drain blood loss; moderate/severe bleeding adjudicated based on the universal definition of perioperative bleeding (3).