Perioperative bleeding is a relevant complication in bariatric surgery and may lead to hemoglobin decrease, blood transfusions, reinterventions, prolonged hospital stay, and increased healthcare costs. Tranexamic acid (TXA), an antifibrinolytic agent, has demonstrated efficacy in reducing surgical bleeding in several surgical specialties, with a favorable safety profile when appropriately used. However, evidence in bariatric surgery remains limited, particularly considering the intrinsically increased thromboembolic risk of obese patients.

The BAR-TAX study is a prospective, single-center study conducted in a high-volume bariatric surgery center, aiming to evaluate the efficacy and safety of perioperative TXA administration compared with standard care without TXA. The primary objective is to assess whether TXA reduces the incidence of clinically significant bleeding within 48-72 hours after bariatric surgery. Secondary objectives include evaluation of hemoglobin drop, transfusion rates, need for hemostatic procedures or reoperation, thromboembolic events, postoperative complications, length of hospital stay, readmissions, and TXA-related adverse events.

Bariatric surgery, including procedures such as Sleeve Gastrectomy, Roux-en-Y Gastric Bypass, Transit Bipartition, and revisional surgery, is associated with a non-negligible risk of perioperative and postoperative bleeding. Clinically significant bleeding may result in adverse outcomes such as increased transfusion requirements, reintervention, prolonged hospitalization, and higher healthcare resource utilization. At the same time, obese patients represent a population at increased baseline risk for venous thromboembolism, requiring careful balancing between bleeding prevention and thromboembolic safety.

Tranexamic acid (TXA) is an antifibrinolytic agent that inhibits plasminogen activation and fibrin degradation, thereby stabilizing clot formation. Its perioperative use has been widely adopted in orthopedic, cardiac, and trauma surgery, with consistent evidence supporting reductions in blood loss and transfusion requirements without a significant increase in thromboembolic events when used according to established protocols. Emerging data in bariatric surgery suggest similar benefits; however, robust prospective data in this specific population are still limited.

The BAR-TAX study is designed as a prospective, non-funded, single-center observational study conducted in a high-volume bariatric surgery unit. Adult patients (≥18 years) with a BMI ≥30 kg/m² undergoing primary or revisional bariatric surgery will be eligible for inclusion. Patients with recent venous thromboembolism, major uncontrolled thrombophilia, severe renal insufficiency, uncontrolled seizure disorders, known TXA allergy, or pregnancy will be excluded.

Patients in the TXA group will receive a standardized perioperative TXA regimen consisting of 2 g administered intravenously during anesthetic induction, followed by 2 g at 8 hours and 2 g at 12 hours postoperatively. All patients will be managed according to standardized perioperative care pathways, including optimized intraoperative hemostasis, venous thromboembolism prophylaxis based on institutional protocols, ERABS principles, and standardized postoperative monitoring.

The primary endpoint is the incidence of clinically significant bleeding within 48-72 hours after surgery, defined by the presence of at least one of the following: hemoglobin drop ≥2 g/dL associated with clinical signs, need for blood transfusion, bleeding requiring endoscopic, radiologic, or surgical intervention, or hemodynamic instability attributable to bleeding. Secondary endpoints include hemoglobin variation at 24 and 72 hours, estimated hidden blood loss, transfusion rate and indications, need for reintervention or hemostatic procedures, 30-day venous thromboembolic events, postoperative complications classified according to Clavien-Dindo, length of hospital stay, readmissions, and TXA-related adverse events such as seizures or allergic reactions.

Inclusion Criteria:

• Age ≥18 years
• Both sexes
• BMI ≥30 kg/m²
• Candidates for primary or revisional bariatric surgery

Exclusion Criteria:

• Recent history of DVT/PE (e.g., <12 months) or major thrombophilia not adequately managed
• Severe renal insufficiency (e.g., eGFR <30 mL/min/1.73 m²) or need for unmanageable dose adjustment
• History of uncontrolled seizures/epilepsy (dose-dependent risk)
• Known allergy to TXA
• Pregnancy