Tranexamic Acid for reduction of intra- and postoperative TRansfusion requirements in elective Abdominal surgery (TATRA): study protocol for an investigator-initiated, multicenter, double-blind, placebo-controlled, randomized superiority trial with two parallel groups.

Background: Intra- and postoperative hemorrhage is a relevant problem in major abdominal surgery, leading to acute anemia and necessitating transfusion of packed red blood cells. It is estimated that in 30% of abdominal surgeries, intra- or postoperative transfusion is required. Transfusion potentially has detrimental health effects and poses a considerable socioeconomic burden. Tranexamic acid, a lysine analog inhibiting plasminogen activation and providing clot stability, has been used to reduce hemorrhage. While there is ample evidence in other surgical disciplines, it is almost completely lacking in abdominal surgery.

Methods: This multicenter double-blind parallel group randomized superiority trial will compare tranexamic acid (loading dose 1000 mg over 10 min prior to skin incision, maintenance dose 125 mg/h continuously until skin closure or until 1000 mg have been administered) to placebo in patients ≥ 18 years undergoing elective esophagectomy, gastrectomy, colectomy, rectal resection, pancreatic resection, or hepatectomy. The primary efficacy endpoint is the intra- or postoperative transfusion of at least one unit of packed red blood cells. Key secondary endpoints are the number of transfused units per patient, estimated intraoperative blood loss, postoperative complications/mortality, length of hospital stay, operation/anesthesia time, D-dimer levels, and quality of life. Sample size calculation is based on the assumption that in the control group, 30% of patients require transfusion while the intervention achieves a risk reduction of 33%, reducing the probability to 20%. With a type one error of 5% and a power of 90%, using a two-sided χ² test, this results in 412 patients per group. Accounting for non-compliance, 425 patients are to be randomized per group. The total trial duration will be 30 months with a recruitment period of 18 months.

Discussion: If the proposed trial yielded positive results, the routine use of tranexamic acid in major abdominal surgery would be supported. This would avoid acute anemia with detrimental effects such as tissue hypoxia and organ injury, as well as the negative immediate and delayed effects of transfusions.

Trial registration: EU CT Nr: 2023-509970-43-01, NCT06414031 . Registered on 10 May 2024.