Decreasing Postoperative Blood Loss and Seizures by Timing of Intravenous Tranexamic Acid 2 Pilot Trial

Decreasing Postoperative Blood Loss and Seizures by Timing of Intravenous Tranexamic Acid in Open Cardiac Surgery (DEPOSITION)-2 Pilot Trial

The goal of this clinical trial is to establish the feasibility of conducting a large trial to determine the optimal timing of intravenous tranexamic acid administration in cardiac surgery. The main questions it aims to answer are:

• Is it feasible to conduct a larger definitive trial?
• Can we measure the systemic tranexamic acid concentration and fibrinolytic potential in the blood samples?

Researchers will compare intravenous tranexamic acid administered before cardiopulmonary bypass versus after cardiopulmonary bypass to see if the systemic tranexamic acid concentration and fibrinolytic potential are similar or better.

Participants will:

• Provide written informed consent
• Receive tranexamic acid during surgery
• Provide blood samples at 5 time points: before surgery, on arrival in intensive care unit, 3 hours after arrival, 6 hours after arrival, and on the next morning.

Postoperative bleeding related to open cardiac surgery increases the rates of complications and mortality. It results from the blood thinners that are needed for use. Intravenous tranexamic acid (TxA) has become a mainstay in cardiac surgical procedures for decreasing bleeding and minimizing transfusion requirements. Although intravenous TxA is usually well tolerated, there is a well-known risk (1 to 4%) of postoperative seizures. This is due to the similarity between TxA and the brain tissues. The aim is to eliminate the risk of seizures and to improve the protection against bleeding. When TxA is used before and during cardiopulmonary bypass (CPB), the presence of systemic TxA during de-airing of the heart and the termination of CPB may facilitate entry of TxA into the brain causing seizures. Administration of TxA after CPB may result in higher systemic concentrations that may be more effective for protecting against bleeding after surgery. The aim is to establish the feasibility of a definitive trial to prove that administration of TxA after CPB can eliminate postoperative seizures and reduce the amount of blood transfusions in patients who have cardiac surgery.

Inclusion Criteria:

1. ≥18 years of age
2. Undergoing a cardiac surgical procedure (i.e., isolated CABG, isolated single cardiac valve surgery or a combination of both or isolated ascending aorta replacement) with the use of cardiopulmonary bypass
3. Provide written informed consent

Exclusion Criteria:

1. Allergy to tranexamic acid

2. Fulfill any of the following transfusion risk factors (A-F):

   A. Emergency surgery B. History of bleeding disorder C. Inherited thromboembolic or hemorrhagic disease D. Infective endocarditis (active) E. Pre-operative thrombocytopenia (<50,000 platelets per µL) F. Pre-operative hemoglobin <110 g/L

3. Estimated glomerular filtration rate <30 mL/min (CKD-EPI equation) or on dialysis

4. Pre-operative hemoglobin >170 g/L

5. Expected circulatory arrest

6. Pregnancy or breast feeding

7. Previous enrollment in DEPOSITION trial

8. Refusal of blood products (e.g., Jehovah's Witnesses)

9. Isolated Pericardiectomy