Abstract

Objectives: Variability in right and left hemiliver drainage volumes of the middle hepatic vein is of special relevance in living donor liver partitioning. Here, we present a comprehensive classification of middle hepatic vein drainage encompassing func-tional and anatomic components with special reference to middle hepatic vein management in adult living donor liver transplantation.
Materials and Methods: We evaluated 153 living donor livers among 100 cases of living donor liver transplantation. With 3-dimensional virtual venous reconstructions and maps, we addressed (1) hepatic venous dominance in the total liver, (2) middle hepatic vein/hemiliver-territorial belonging, (3) middle hepa-tic vein drainage contribution to right and left hemilivers based on middle hepatic vein/hemiliver-congestive volume index, and (4) middle hepatic vein anatomic branching patterns.
Results: With an established clinical threshold of 30% to 40% middle hepatic vein-congestive volume index for graft selection, a strong correlation between venous dominance, hemiliver belonging, and congestive volume index in overlap with anatomic branching classification was demonstrated. Functional middle hepatic vein variants b and c in overlap with middle hepatic vein branching types A and C implicated middle hepatic vein reconstruction/inclusion in right/left hemiliver grafts. Functional middle hepatic vein variant a (analog to middle hepatic vein branching type B) exhibited safe small congestive drainage volumes in both hemilivers.
Conclusions: The proposed middle hepatic vein classification addressed a triple correlation between hepatic vein (total liver volume) dominance and middle hepatic vein (hemiliver volume) belonging related to the middle hepatic vein-congestive volume index in right and left hemiliver as follows: (1) categorize functional middle hepatic vein variants based on congestion risk, (2) identify the left hepatic vein/left hemiliver non-congestive volume index as an additional key parameter in right graft selection, and (3) represent a predictive guide for middle hepatic vein management in right/left graft living donor liver transplantation.