# Intraoperative blood loss as a predictor of outcomes in liver transplantation: determining optimal cutoff values for improved graft survival

## TL;DR

This study shows that blood loss during liver transplants affects graft survival and identifies 25 mL/kg as a critical cutoff for better patient outcomes.

## Contribution

The study identifies a specific blood loss cutoff (25 mL/kg) that predicts graft survival in liver transplant patients.

## Key findings

- Adjusted blood loss (aEBL) is an independent risk factor for graft survival at 1 and 3 years.
- Patients with aEBL below 25 mL/kg had significantly better graft survival rates at 90 days, 1 year, and 3 years.
- Higher MELD-Na scores and DCD donor status were linked to exceeding the 25 mL/kg aEBL threshold.

## Abstract

Liver transplantation (LT) remains the definitive treatment for end-stage liver disease, with intraoperative estimated blood loss (EBL) receiving limited attention despite its potential impact on outcomes. This study investigated the impact of EBL on graft survival (GS) in LT recipients and aimed to identify a clinically optimal EBL cutoff to guide surgical management.

This observational cohort study analyzed 914 adult patients who underwent primary orthotopic LT at Ohio State University Wexner Medical Center between January 2016 and December 2023. Intraoperative EBL was calculated by subtracting the volume of salvaged blood from the total volume lost during surgery, then normalized by dividing by the patient’s body weight, resulting in adjusted EBL (aEBL). The primary outcome was GS, defined as the time from transplantation to graft failure, re-LT, or death. Kaplan-Meier analysis and Cox regression were used to evaluate GS, and a restricted cubic spline with five knots was applied to determine the optimal aEBL cutoff.

Multivariate analysis confirmed aEBL as an independent risk factor for 1-year GS (HR:1.01, 95%CI:1.00-1.01, p < 0.001) and 3-year GS (HR:1.01, 95%CI:1.00-1.01, p < 0.001). The optimal aEBL cutoff was established at 25.0 mL/kg. Patients with aEBL < 25.0 mL/kg demonstrated superior GS rates at 90 days (p = 0.03), 1 year (p = 0.007), and 3 years (p = 0.003) compared to those with aEBL ≥ 25.0 mL/kg. Higher MELD-Na scores (OR:1.07, 95%CI:1.05–1.09, p < 0.001) and DCD donor status (OR:1.61, 95%CI:1.13–2.29, p = 0.01) were significant predictors of exceeding this threshold.

This study establishes aEBL as an independent risk factor for GS in LT recipients and identifies 25.0 mL/kg as a significant cutoff impacting both short-term and long-term outcomes. These findings underscore the importance of tailoring blood loss management to individual patient characteristics, particularly body weight, and suggest a practical approach to enhance outcomes for LT recipients.

The online version contains supplementary material available at 10.1007/s00423-025-03898-z.