International multicenter study of ultralow graft-to-recipient weight ratio grafts in adult living donor liver transplantation

Decreasing the graft size in living donor liver transplantation (LDLT) increases the risk of early allograft dysfunction. Graft-to-recipient weight ratio (GRWR) of 0.8 is considered the threshold. There is evidence that smaller volume grafts may also provide equally good outcomes, the cut-off of which remains unknown. In this retrospective multicenter study, 92 adult LDLTs with a final GRWR ≤0.6 performed at 12 international liver transplant centers over a 3-year period were included. Perioperative data including preoperative status, portal flow hemodynamics (PFH) and portal flow modulation, development of small for size syndrome (SFSS), morbidity, and mortality was collated and analyzed. Thirty-two (36.7%) patients developed SFSS and this was associated with increased 30-day, 90-day, and 1-year mortality. The preoperative model for end-stage liver disease and inpatient status were independent predictors for SFSS ( P <.05). Pre-liver transplant renal dysfunction was an independent predictor of survival (hazard ratio 3.1; 95% confidence intervals 1.1, 8.9, P =.035). PFH or portal flow modulation were not predictive of SFSS or survival. We report the largest ever multicenter study of LDLT outcomes using ultralow GRWR grafts and for the first time validate the International Liver Transplantation Society-International Living donor liver transplantation study group-Liver Transplantation Society of India consensus definition and grading of SFSS. Preoperative recipient condition rather than GRWR and PFH were independent predictors of SFSS. Algorithms to predict SFSS and LT outcomes should incorporate recipient factors along with GRWR.