Characterization of the middle hepatic artery and its relevance to living donor liver transplantation.

In comparison with the left and right hepatic arteries, there is a relative lack of information on the middle hepatic artery (MHA). In this study, data obtained by multidetector computed tomography from 145 patients were studied to evaluate anatomical variations of the MHA, a hilar artery that primarily supplies hepatic segment 4. An MHA was present in 103 (71%) of the subjects. In livers that had a replaced left hepatic artery, the MHA originated from the right hepatic artery; in livers that had a replaced right hepatic artery, it originated from the left hepatic artery. It always arose directly or indirectly from the common hepatic artery, from which the gastroduodenal artery also arose. We classified MHAs into 5 types according to the anatomical variations of the origin. This classification may have major relevance to modern surgical practice related to living donor liver transplantation (LDLT). The new classification of hepatic arterial anatomy may enhance the acquisition of further knowledge on arterial development, and its application may favorably influence the outcome of LDLT.