SP 8.10 GRWR (Graft-to-Recipient Weight Ratio) ≥ 0.7% Is a Safe Threshold in Standard Living Donor Liver Transplantation: An Outcome Analysis of 2,506 Cases
Hemant Sharma, Selvakumar Naganathan, Subhash GuptaAbstract
Background
Early evidence suggests acceptable outcomes occur at GRWR ≤ 0.6% when portal pressure modulation is employed. However, the minimum safe GRWR achievable in standard-practice without portal interventions needs review. The traditional 0.8% threshold may be unnecessarily restrictive.
Methods
We analysed 2,506 consecutive LDLT-cases performed without routine portal-pressure-modulation, comprising 1,868 modified right, 308 extended right, 71 standard right, 111 left lobe, and 114 left lateral grafts. Of these, 1,892 had complete follow-up data. Minimum safe GRWR was determined using survival-based inflection-point analysis and Kruskal-Wallis testing at 0.1% increments. Three thresholds (0.6%, 0.7%, 0.8%) were compared using Mann-Whitney U tests. Stratified analysis evaluated whether GRWR remained predictive after adjusting for absolute graft weight. Multivariate logistic regression included MELD score, recipient age, and graft weight.
Results
Overall survival was 81.0%. A critical inflection occurred at 0.7% GRWR: patients below 0.7% achieved 71.4% survival (n=105), while those at 0.7% or higher achieved 81.5% survival (n=1,787), a 10.1 percentage-point improvement (p=0.010). The 0.8% threshold provided no additional safety; survival below 0.8% was 77.6% (n=272) versus 81.5% at 0.8% or higher (n=1,620), a nonsignificant 4.0 percentage-point difference (p=0.123). The 0.7-0.8% range achieved 82.9% survival (n=152) with lower complication rates at five-year follow-up. Stratified analysis showed GRWR lost predictive value after adjusting for graft weight (all p>0.05), while graft weight remained significant (p=0.023).
Conclusions
For centres using standard techniques without portal pressure modulation, GRWR of 0.7% represents an evidence-based minimum threshold, offering 10.1 percentage-point survival benefit over lower values (p=0.010). The 0.8% threshold is unnecessarily restrictive (p=0.123).