Impact of Portal Hemodynamic Changes in Partial Liver Grafts on Short-Term Graft Regeneration in Living Donor Liver Transplantation

Background. Regeneration of partial liver grafts is critical for successful living donor liver transplantation (LDLT), especially in adult recipients. The purpose of this study was to investigate the intraoperative hemodynamic changes in partial liver grafts and characterize their potential impact on post-transplant liver regeneration in LDLT. Methods. We examined the portal venous flow (PVF) and hepatic arterial flow (HAF) to partial liver grafts by means of ultrasonic transit time flowmeter of donors immediately before graft retrieval and of the corresponding recipients after vascular reconstruction in 48 LDLT cases. We evaluated post-transplant liver regeneration according to the changes in graft liver volume between the time of transplantation and the 7th post-transplant day. Results. There was a significant increase in PVF to the partial liver grafts in recipients (rPVF) compared with that in donors. In contrast, graft HAF in recipients significantly decreased compared with that in donors. The rPVF inversely correlated with graft weight (GW)-recipient body weight ratio (GRWR), whereas HAF volume showed no significant correlation. The rPVF/GW positively correlated with the rate of liver regeneration (GRR), which inversely correlated with GRWR. The rPVF/GW was significantly higher, and GRR tended to be larger in the small graft group than in the non-small graft group. Conclusions. Intraoperative portal hemodynamic changes in partial liver grafts strongly affect their post-transplant regeneration. In particular, in small liver grafts, an immediate and remarkable increase in graft PVF may contribute to rapid liver regeneration after LDLT if the increased PVF remains within a safe range.