Liver regeneration and venous collateral formation in the right lobe living-donor remnant: Segmental volumetric analysis and three-dimensional visualization

BACKGROUND: In left lobe (LL) living-donor liver transplantation (LDLT), hepatic venous congestion (HVC) caused by ligation of the middle hepatic vein tributaries is unavoidable in the right lobe (RL) donor remnant. METHODS: To clarify the impact of HVC on liver regeneration and venous collateral formation (VCF), we used three-dimensional computed tomography to examine the volumes of total/segmental liver and HVC and the degree of VCF; preoperative data were compared with data obtained on postoperative day (POD) 35 in 13 LL LDLT donors. RESULTS: On POD 35, the congestion rate decreased from 32.5% to 1.6% and the total liver regeneration rate was 81.7%. Preoperatively, the anterior sector-to-RL volume ratio was significantly lower, and the posterior sector-to-RL volume ratio was significantly higher than postoperatively (56.7% vs. 52.9%, P<0.01, and 36.9% vs. 41.5%, P<0.01, respectively). There was no correlation between degree of HVC and liver regeneration. Obvious VCF was found in five (38.5%) cases. The RL and posterior sector volume per square meter of body surface area in the VCF group were significantly lower than that in the non-VCF group (412 cm/m vs. 492 cm/m, P<0.01, and 140 cm/m vs. 190 cm/m, P<0.01, respectively). The preoperative congestion rate and liver regeneration rate were not significantly different between the groups. CONCLUSIONS: Reconstruction of the middle hepatic vein tributaries in the RL donor remnant might not be necessary in LL LDLT, because the HVC improved dramatically by POD 35 regardless of the development of VCF.