Identification of veno-occlusive regions in a right liver graft after reconstruction of vein segments 5 and 8: Application of indocyanine green fluorescence imaging

In living donor liver transplantation using a right liver graft (RLG) without the middle hepatic vein, the stumps of vein segment 5 (V5), vein segment 8 (V8), or both are considered for reconstruction to prevent postoperative liver dysfunction due to venous occlusion.1, 2 Recent advances in imaging studies allow accurate estimations of regional liver volumes with postoperative venous occlusion after liver resection.3 Methods to confirm such regions intraoperatively, however, have not yet been established. Here we describe the identification of a large veno-occlusive region in an RLG after reconstruction of V5 and V8 with an indocyanine green (ICG) fluorescence imaging technique. A 52-year-old male underwent living donor liver transplantation for alcoholic liver cirrhosis. The donor was his 50-year-old wife. The parenchymal volumes of the portal segments and hepatic regions drained by the hepatic vein tributaries in the candidate graft were calculated on the basis of computed tomography with region-growing software (Organ Volume Analysis, Hitachi Medico, Chiba, Japan).4 The sum of the liver volumes of the regions drained by the right hepatic veins [380 mL or 30.7% of the recipient standard liver volume (RSLV): 1238 mL], V5 (83 mL or 6.7% of RSLV), and V8 (71 mL or 5.7% of RSLV) was 534 mL (43.1% of RSLV). In contrast, the liver volume of the RLG was 637 mL (51.4% of RSLV), and this suggested the presence of a tributary draining the regions between the right and left liver (an intersegmental vein; see the arrowhead in the right panel of Fig. 1). The procurement of the graft was scheduled to harvest the regions fed by the right portal vein (see the white, dotted line in the left panel of Fig. 1). Because of its narrow diameter and our ability to secure a sufficient graft volume without reconstruction, we planned to sacrifice the intersegmental vein.5 The RLG was harvested along the demarcation line, which was demonstrated by the clamping of the right portal vein (see the left panel of Fig. 2). The right hepatic vein, V5, V8, portal vein, and hepatic artery were reconstructed (see the right panel of Fig. 2). ICG (1.65 mg or 2.5 μg/mL of the graft liver volume) was then administered intravenously to identify the veno-occlusive regions.6 After 300 seconds, a clear demarcation was indicated between the veno-occlusive regions [corresponding to 103 mL (637 mL − 534 mL) or 8.3% of RSLV] and the non–veno-occlusive regions (Fig. 3). Despite the identification of large veno-occlusive regions, further reconstruction was not performed as preoperatively planned.5 The postoperative course was uneventful, and the patient was discharged on postoperative day 40. Regions with venous occlusion are considered to have poor function.6 An RLG with reconstruction of the tributaries of the middle hepatic vein (a so-called modified RLG), therefore, will not have the same function as an RLG with the trunk of the middle hepatic vein (a so-called extended RLG).7 In the present case, ICG fluorescence imaging allowed us to identify veno-occlusive regions which had been drained by the intersegmental vein. In an RLG without V5 and V8 reconstruction in a different case, the regions which had been drained by V5, V8, and the intersegmental vein were visualized as veno-occlusive regions (Fig. 4). The major advantage of this technique is that it provides real-time visualization of regions with venous occlusion and serves as a guide for determining the need for venous reconstruction. One of the drawbacks of this technique is that it cannot be applied to estimate postoperative venous occlusion without laparotomy because of the need for observing the liver surface directly. In conclusion, preoperative and intraoperative evaluations of veno-occlusive regions are important for determining whether the metabolic demands of recipients and donors are satisfied and enhance the safety of living donor liver transplantation. Yoshikuni Kawaguchi, M.D. Yasuhiko Sugawara, M.D., Ph.D. Takeaki Ishizawa, M.D., Ph.D. Shouichi Satou, M.D. Junichi Kaneko, M.D. Sumihito Tamura, M.D. Taku Aoki, M.D. Yoshihiro Sakamoto, M.D. Kiyoshi Hasegawa, M.D. Norihiro Kokudo, M.D. Artificial Organ and Transplantation Surgery DivisionDepartment of SurgeryGraduate School of MedicineUniversity of Tokyo, Tokyo, Japan