Hemodynamics-compliant reconstruction of the right hepatic vein for adult living donor liver transplantation with a right liver graft

Abstract

Secure reconstruction of the right hepatic vein (RHV) is essential for the successful implantation of a right liver graft during living donor liver transplantation (LDLT). To develop reliable surgical techniques for RHV reconstruction, we performed 3 concurrent studies: a simulation study using a fluid dynamics experimental model and a computational simulation model; an observational study analyzing the hemodynamic changes during radiological interventions for RHV stenosis; and a prospective clinical study establishing hemodynamics-compliant surgical techniques. The simplified fluid dynamics experimental model revealed that actually measured outflow volumes were very similar to theoretical values derived from a fluid dynamics formula. The computational simulation model showed that outflow decreases were nearly linearly correlated with the degree of stenosis when it exceeded 50%. The clinical observational study revealed that mild (≤50%), moderate (50%-75%), and severe RHV stenoses (≥75%) had mean pressure gradients of 2.5 ± 1.0, 6.6 ± 2.3, and 9.6 ± 2.8 mm Hg, respectively. The prospective clinical study was performed for patients who underwent RHV reconstruction with RHV angle blunting and inferior vena cava enlargement (n = 274); a historical control group of patients who underwent reconstruction by other methods (n = 225) was also used. RHV stenting within 2 weeks and 1 year was necessary for 1 patient (0.4%) and 5 patients (1.8%) in the study group, respectively, and for 9 patients (4.0%) and 21 patients (9.1%) in the control group, respectively (P < 0.01). The mean cephalocaudal length of patulous RHV anastomoses was greater in the study group versus the control group (P < 0.001). In conclusion, our modified RHV reconstruction technique significantly reduces the risk of RHV stenosis. We thus suggest the routine or selective use of this technique as a part of graft standardization for LDLT using a right liver graft.