Are the Classifications Used to Determine Hepatic Artery Variations in Liver Donors Sufficient?

Objectives: Liver transplant from a living donor is a more challenging procedure than liver transplant from a deceased donor, given that optimal blood supply to both the remaining liver segment in the donor and the graft must be maintained to ensure successful donor hepatectomy. During surgical planning, in addition to calculation of volumetric data with multidetector tomography, the anatomy of the hepatic artery, portal vein, and hepatic vein must also be meticulously determined, with the most commonly used clas-sification methods for hepatic artery variations being the Michels and Hiatt classifications. Although these classification methods can accurately group most patients, we often encounter a large number of patients who cannot be grouped or who exhibit other variations that accompany the defined group.

Materials And Methods: We examined the hepatic artery computed tomography angiography tests taken before the operations of 290 living liver donors performed at our hospital between 2012 and 2023 and grouped the hepatic artery variations according to the Michels and Hiatt classifications. We also identified and classified cases that could not be classified into the groups of either classification method.

Results: We identified 144 patients (62.61%) who fit the Michels classification. Eighty-six patients (37.39%) did not conform to the groups defined in either classification system. We identified 173 patients (75.22%) patients who fit the Hiatt classification, and 57 (24.78%) who did not. Notable variations included those in the medial and lateral branches of the left hepatic artery, those in the origin of the right hepatic artery, and the trifurcation of the common hepatic artery into the gastroduodenal artery, right hepatic artery, and left hepatic artery.

Conclusions: The Michels and Hiatt classification systems are not sufficient for determining hepatic artery variations in many patients. A more comprehensive classification system that includes segmental arteries is needed.