Effect of Portal Vein Types on Estimated Remnant Volume in Living Donor: Preoperative CT Assessment

The aim of this study is to examine the effect of portal vein types on the ratio of the right-left lobe liver volumes, as well as the insufficient estimated remnant liver volume (ERLV) during the preoperative assessment of donor candidates for right-lobe liver transplantation.

The preoperative abdominal CT examinations of the donor candidates in a single institution between December 2018 and May 2022 were retrospectively evaluated. Portal vein types are divided into 3; classical anatomy was considered type 1, PV trifuction was considered type 2, and if the first branch arising from the main portal vein is the right posterior branch, it was accepted as type 3. Other configurations were defined as type 4. The total, right-left lobe liver volumes, the ERLV, and the portal vein variations were noted. The chi-square test was performed to assess the correlation between portal vein types, the ratio of the right-left lobe volumes, and the ERLV ratio below 30%. Tamhane's T2 post hoc tests were performed for pairwise comparison to assess the right-left lobe volume ratio among groups.

287 donor candidates (mean age, 35 years ± 8.2; 174 men) were evaluated. The volume ratio of median volume of the right and left lobe was significantly higher in candidates with type 3 portal veins compared to those with type 1 portal veins (2 (1.3-3.5) and 2.1 (1.6-3.2), respectively, p = 0.017). The ERLV ratio below 30% was significantly higher in donor candidates with type 3 portal veins (42.9%) compared to those with type 1 and 2 portal veins (24.6%, 20%)) respectively, p = 0.030).

Due to its propensity to result in insufficient ERLV in the donor, the presence of a type 3 portal vein should be evaluated during the preoperative evaluation. Secondary abstract: This study suggests that donor candidates with type 3 portal vein exhibit a notable rise in the frequency of insufficient remnant liver volume during the preoperative assessment.