 The investigators will perform a prospective observational study of 100 patients to investigate the link between perioperative platelet activation, systemic inflammatory responses, and end organ injury following cardiac surgery. Patient inclusion criteria for this study will be based on the results from our retrospective study of 4201 patients undergoing CABG surgery on CPB. Here, the investigators identified a significant incidence of thrombocytopenia and an association between thrombocytopenia and increased risk for developing postoperative AKI. Consequently, the proposed study is designed to determine whether postoperative platelet activation contributes to a systemic inflammatory response and, hence, has a causative effect on end organ injury. 