Phase II Study to Compare MDCO-2010 vs Placebo and Tranexamic Acid in Patients Undergoing Cardiac Surgery

Inclusion Criteria: * For Stage 1: Planned primary isolated CABG surgery * For Stage 2: Planned primary isolated CABG surgery, OR Planned primary combined CABG and aortic valve replacement surgery * Men, aged 18 to 85 years, or Women, aged 18 to 85 years, either of postmenopausal status, defined as ≥1 year since last menstrual period AND if less than 65 years old with a negative pre-operative pregnancy test within 24 hours of surgery OR with medical history of hysterectomy or bilateral oophorectomy * Written informed consent Exclusion Criteria: * Off-pump surgery or hybrid procedures * Patients undergoing repeat sternotomy * Planned deep hypothermic circulatory arrest (\<28°C) * Known allergy, sensitivity, or contraindications to tranexamic acid * Epileptiform disorders, history of seizure activity, or anticonvulsive medication * Administration of clopidogrel, ticagrelor or ticlopidine within 5 days prior to surgery or prasugrel within 7 days prior to surgery. * Administration of low molecular weight heparin, glycoprotein IIb/IIIa inhibitors, or fondaparinux within 12 hours prior to surgery * Known history of coronary stent thrombosis within the last three months * History of stroke or transient ischemic attack within 3 months prior to surgery * History of deep venous thrombosis or pulmonary embolism * LVEF ≤35% or Grade III or IV * Body mass index \<20 or \>35 * Known active gastrointestinal (GI) or other non-catheterization bleeding within 7 days prior to surgery * Preoperative coagulation abnormalities defined as: * Platelet count \<100,000/L or \>350,000/L, or * International normalized ration (INR) \>1.5, or * Hematocrit \<36%, or * aPTT \>1.5 x ULN * Major surgical procedures within 30 days prior to surgery * Patient inability or refusal to receive donor blood products if necessary * Creatinine \>2 mg/dL or estimated glomerular filtration rate (eGFR) (calculated using Modification of Diet in Renal Disease \[MDRD\] equation \<30 mL/min) * Known heparin-induced thrombocytopenia type II * Known history of thrombophilia, such as AT-III, Protein C or Protein S deficiency, Factor V Leiden, anti-phospholipid syndrome * Active liver disease defined as any known current infectious, neoplastic or metabolic pathology of the liver OR ALT or AST elevation \>2x ULN or total bilirubin elevation \>1.5x ULN at Screening * Any condition requiring ongoing chronic immunosuppressive medication * Malignancy within 5 years prior to surgery * Receipt of an investigational drug or device within 60 days prior to surgery Any other condition which, in the opinion of the Principal Investigator, would put the subject at increased risk from participating in the study or otherwise prevent a patient"s participation in the study