Small-for-size graft in liver transplantation.

Controversies on small-for-size (SFS) graft in liver transplantation have evolved in parallel with the history of living donor liver transplantation for adults. It is true that the liver regenerates rapidly within a limited threshold. But 'normal' liver weight itself is variable and the influences of variable liver graft and extrahepatic factors are not negligible in pathological condition. Clinical features of 'SFS syndrome' are neither specific nor inevitable in low-weight liver and many other factors than actual graft weight contribute to their occurrence. Among them, early elevation of portal venous pressure highly probably plays a key role. In the clinical trials of surgical modification and local pharmacological manipulation targeting portal hemodynamics and tissue congestion, it may be the time to discard an excessive fear for SFS grafts and to minimize unnecessary withdrawal from the opportunity of transplantation.