Safety of Tranexamic Acid in Reducing Bleeding in Adults Undergoing Spinal Surgery

Spinal fusion can be associated with significant blood loss requiring allogeneic blood transfusion (ABT). Ongoing concerns about the costs, risks, and availability of allogeneic blood have prompted the implementation of multiple techniques (preoperative erythropoetin, autologous pre-donation, intra-operative blood salvage, and induced hypotension) to reduce the necessity of ABT. However, 28% of patients undergoing spinal fusion at the Toronto Western Hospital still receive ABT. Also, none of these modalities (with the exception of induced hypotension) actually reduce the amount of blood shed from the surgical wound; thus the severity of anemia is largely unaffected. Consequently, many of these patients can suffer from adverse effects of anemia postoperatively as well as potential complications from blood transfusions.

The underlying assumption of the proposed study is that excessive fibrinolysis occurs during spinal fusion surgery. This can result in increased and recurrent blood loss, which can exacerbate the significant amount of bleeding already associated with major spine surgery.

Tranexamic acid - an antifibrinolytic drug blocks the dissolution of hemostatic fibrin, which stabilizes fibrin structures, and thus may decrease blood loss secondary to increased fibrinolysis.

This research proposal will test the following hypotheses:

• Tranexamic acid reduces the estimated perioperative blood loss in adult patients undergoing elective spinal fusion.
• Tranexamic acid reduces the need for blood transfusion in adult patients undergoing elective spinal fusion.

This multi-centered trial will be valuable for establishing the efficacy and safety of tranexamic acid for reducing blood loss and allogeneic blood transfusion in adults having elective spinal fusion. Tranexamic acid is easy to administer, is relatively inexpensive, and has not been associated with significant adverse effects. If it is shown to be efficacious, it can be incorporated into routine clinical practice as part of the multi-modal perioperative blood conservation techniques currently used to reduce perioperative blood loss, transfusion and the risk of allogeneic blood transfusion.

Inclusion criteria

• All adult patients (greater than 18 years old) undergoing elective posterior thoracic/lumbar instrumented spinal fusion.

Exclusion criteria

• Participation in another clinical trial
• Allergy to TA
• Spinal tumor/Intradural pathology
• Ankylosing spondylitis
• Acquired disturbances of color vision
• Preoperative anemia (Hb <110 in females, Hb <120 in males)
• Refusal of blood products (Jehovah's witnesses)
• Preoperative use of anticoagulant therapy - coumadin, heparin within 5 days of surgery
• Fibrinolytic disorders requiring intraoperative antifibrinolytic treatment
• Hematological disease (thromboembolic events, hemoglobinopathy, coagulopathy or hemolytic disease)
• Preoperative platelet count <150,000/cubic mm, INR>1.4, prolonged PTT
• Significant co-morbidities: Previous MI ; severe ischemic heart disease (NYHA Class III, IV) ; severe pulmonary disease ; chronic renal failure ; hepatic failure ; uncontrolled hypertension
• Pregnancy or lactation