End-stage Liver Disease (ESLD)

Machine perfusion (MP) has become routine clinical practice in liver transplantation. However, as the field has matured, direct randomized comparisons between distinct MP modalities have become increasingly impractical, given that donor and graft characteristics often predetermine the optimal preservation strategy. Consequently, many studies continue to reference historical benchmark cohorts from the pre-perfusion era, or use risk scores developed before routine utilization of MP. These cohorts, while once valuable, fail to account for the paradigm shift that MP has introduced. Likewise, commonly used donor- and recipient-based risk scores were developed prior to the adoption of MP. While these scores aim to assess survival or morbidity after transplantation, none of them guide decisions about MP use or the most suitable perfusion protocol. As MP technologies continue to evolve there is a critical need for an updated reference framework that accurately reflects current clinical practice and captures the best achievable outcomes across all MP modalities.

The goal of the REFIL-2 study is to evaluate the effectiveness of a low splanchnic blood volume restrictive fluid management strategy (a strategy that involves limiting fluid administration and prioritizing the use of medications that raise blood pressure during surgery, combined with phlebotomy) in improving patients' recovery after surgery. The study compares the low splanchnic blood volume restrictive fluid management strategy to an optimized cardiac-output liberal fluid management strategy (which involves administering more fluids to raise blood pressure with less reliance on medications). Outcomes important to patients will be measured. This study (REFIL-2) had a vanguard phase (internal pilot) that included 138 patients (NCT05647733). The patients included in the vanguard pilot phase were not compared between groups but only analyzed descriptively using aggregated data. Only feasibility metrics were compared (see NCT05647733). These 138 patients were thus rolled into the REFIL-2 trial and included in the final sample size reported herein.

We propose a multi-center randomized trial to test the primary hypothesis that tranexamic acid is superior to placebo on blood loss in adult orthotopic liver transplantation within the initial 24 hours and that tranexamic acid is non-inferior to placebo for a composite of thrombotic events within the initial 7 postoperative days. Secondarily, we will determine whether tranexamic acid is superior to placebo on total postoperative drainage volume and blood product transfusion within the initial 3 postoperative days. We propose to randomize patients to 2.0 g of tranexamic acid intravenously at the start of surgery or a comparable volume of 0.9% normal saline placebo. Because demonstrating safety will require more patients, our sample size is based on safety. Randomizing 1546 patients will provide 80% power for detecting a non-inferiority margin of 4% with a baseline incidence of 10% for composite thrombotic events within the initial 7 postoperative days.