Topical Application of Tranexamic Acid to Reduce Post-operative Bleeding in Coronary Artery Bypass Surgery
The goal of this project is to determine whether the use of tranexamic acid, a clot-promoting drug, applied topically over the heart in coronary artery bypass graft surgery (CABG) will reduce post operative blood loss. The investigators' hypothesis is that the use of a tranexamic acid-containing cardiac bath prior to chest closure will result in a statistically significant reduction in blood loss and transfusion requirements in patients who undergo CABG.
Coronary Artery Disease
Drug: Tranexamic Acid
Drug: normal saline
|Study Design:||Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)
Primary Purpose: Prevention
|Official Title:||Topical Application of Tranexamic Acid to Reduce Post-operative Bleeding in Coronary Artery Bypass Surgery|
- Total Volume of Blood Loss From Mediastinal Chest Tubes at Time of Removal (Assuming the Total Volume of Loss is Blood). [ Time Frame: From ICU admission post-operatively to mediastinal chest tube removal (placebo group = 20.6 hours; trial group = 19.8 hours) ] [ Designated as safety issue: No ]According to standard practice, research participants were be transferred to the intensive care unit (ICU) for post-operative monitoring. Measurement of chest tube output began immediately on arrival to the ICU. Hourly measurements were recorded. Data collection ended upon chest tube removal, or return to the operating room for exploratory surgery due to massive blood loss. As per ICU protocol, chest tubes were be removed when blood loss was recorded to be less than 200mL after six consecutive hours.
- Number of Units of Packed Red Blood Cells (PRBC) Transfused Following Coronary Artery Bypass Graft Surgery [ Time Frame: From ICU admission to transfer to the Cardiology Ward (placebo group = 24.4 hours; trial group = 24.7 hours) ] [ Designated as safety issue: No ]Research participants were to receive a blood transfusion in the Intensive Care Unit (ICU) post-operatively if hemoglobin reached a nadir of 80g/L, or at the discretion of the intensivist or cardiac surgeon according to patient clinical status. Transfusion was quantified based on the number of units of PRBC received. (1 unit = 1 bag of blood, as prepared by Canadian Blood Services). Clinical status of research participants was followed throughout their duration in the ICU only. Participation in this study ended upon transfer out of the ICU, to the Cardiology Ward.
- Volume of Blood Loss at 6 Hours [ Time Frame: 6 hours following admission to the Intensive Care Unit ] [ Designated as safety issue: No ]Volume of chest tube loss at 6 hours (assuming the total volume of loss is blood).
- Volume of Blood Loss After 12 Hours [ Time Frame: 12 hours following admission to the Intensive Care Unit ] [ Designated as safety issue: No ]Volume of chest tube loss at 12 hours (assuming the total volume of loss is blood).
|Study Start Date:||December 2011|
|Study Completion Date:||June 2012|
|Primary Completion Date:||April 2012 (Final data collection date for primary outcome measure)|
Experimental: Trial Drug
Solution containing 2 grams tranexamic acid + normal saline
Drug: Tranexamic Acid
Solution containing 2 grams (20mL) tranexamic acid + normal saline (50mL), for a total volume of 70mL poured over the heart as a 'cardiac bath' prior to sternotomy closure near the end of surgery. Total duration of immersion is approximately 10 minutes, until mediastinal chest tubes are connected to suction.
Placebo Comparator: Placebo
Drug: normal saline
A total volume of 70mL of normal saline poured over the heart as a 'cardiac bath' prior to sternotomy closure near the end of surgery. Total duration of immersion is approximately 10 minutes, until mediastinal chest tubes are connected to suction. Identical in appearance to the trial drug, and is visually indistinguishable.
Bleeding is expected during major surgeries. In patients who undergo CABG, the risk for bleeding is increased because of the need for intra-operative anticoagulation, or thinning, of patient blood. This anticoagulation is necessary to reduce the risk of thrombosis potentially precipitated by the cardiopulmonary bypass machine, which pumps blood throughout the body while the surgeon operates on the heart.
Strategies are currently used in the operating room to minimize blood loss and the need for allogenic blood transfusion during and after cardiac surgeries. These strategies include the use of intravenous antifibrinolytic agents, intra-operative red blood cell salvage devices, and topical fibrin sealants. Although the risk of infection from a blood transfusion is very small with modern methods of blood screening, the risk of developing a transfusion reaction is possible and not predictable. Therefore, it is preferred to avoid administering a blood transfusion unless absolutely necessary.
The use of topical antifibrinolytic agents has been explored to further reduce blood loss in cardiac surgery. Several trials have been published in the literature since 1993 evaluating the efficacy of various antifibrinolytic medications applied topically, as a cardiac bath, prior to chest closure in CABG patients to reduce post-operative blood loss and potential need for blood transfusion.
The applicability of the methodology utilized in these studies, however, is limited in the context of the current Canadian practices of cardiac surgery. Considerable differences in the perioperative strategies of these trials are seen, in comparison to current North American practices of cardiac surgery. These trials also compared use of topically applied antifibrinolytic agents, including the lysine analogue tranexamic acid, to a control in the absence of intravenous antifibrinolytic agents. The use of intravenous lysine analogues to reduce peri-operative bleeding has now become a near-standard of care in CABG patients.
Currently, the only available antifibrinolytic agent in Canada is the lysine analogue tranexamic acid. This drug is widely used administered as an intravenous preparation in cardiac surgery because its safety profile and reduction in blood loss and frequency of blood transfusion.
There is presently no published randomized controlled trial evaluating blood loss in CABG patients who have received intravenous tranexamic acid, plus topical tranexamic acid or placebo.