Hepatic Arterial Buffer Response Maintains the Homeostasis of Graft Hemodynamics in Patient Receiving Living Donor Liver Transplantation

Background: In living donor liver transplantation (LDLT), the hepatic hemodynamics plays important roles in graft regeneration, and the hepatic blood inflows are associated with graft size. However, the data of interplay between the hepatic arterial buffer response (HABR) and graft-to-recipient weight ratio (GRWR) in clinical LDLT are lacking.

Aims: To identify the effect of the HABR on the hepatic hemodynamics and recovery of graft function and to evaluate the safe lower limit of the GRWR in carefully selected recipients.

Methods: Portal venous and hepatic arterial blood flow was measured in recipients with ultrasonography, and the graft functional recovery, various complications, and survive states after LDLT were compared.

Results: In total, 246 consecutive patients underwent LDLT with right lobe grafts. In total, 26 had a GRWR < 0.7 % (A), 29 had a GRWR between 0.7 and 0.8 % (B), and 181 had a GRWR > 0.8 % (C). For small-for-size syndrome, there was no significant difference (P = 0.176). Graft survival rates at 1, 3, and 5 year were not different (P = 0.710). The portal vein flow and portal vein flow per 100 g graft weight peaks were significantly higher in the A. Hepatic arterial velocity and hepatic arterial flow decreased in all the three groups on postoperative day 1; however, the hepatic arterial flow per 100 g graft weight was close to healthy controls.

Conclusions: HABR played important roles not only in the homeostasis of hepatic afferent blood supply but also in maintaining enough hepatic perfusion to the graft.