Hiroyuki Furukawa, Tsuyoshi Shimamura, Tomomi Suzuki, Masahiko Taniguchi, Kenichiro Yamashita, Minoru Ohta, Toshiya Kamiyama, Michiaki Mastushita, Satotu Todo. Department of Organ Transplantationand Regenerative Medicine, Hokkaido University School of Medicine, Sapporo, Hokkaido, Japan; Division of Organ Transplantation, Hokkaido University Hospital, Sapporo, Hokkaido, Japan; Department of General Surgery, Hokkaido University School of Medicine, Sapporo, Hokkaido, Japan

Introduction:The unique ability of the liver to regenerate quickly after resection makes living donor liver transplantation (LDLT) possible. This regeneration process and functional recovery in humans are still widely unexplored.

Materials and methods: From March 2000 to September 2006, 125 living donors underwent hepatectomy for LDLT in our center. Of 125, 89 donors were involved in the study. Volumetry was obtained at 1, 2, 4, 12 weeks after hepatectomy using 3D software from CT scan. Technetium-99m-DTPA-garactosyl-human serum albumin liver scintigraphy was used to determine the liver function at 1, 2, 4, 12 weeks after hepatectomy. HH15 (=count for the heart at 15 minutes/ count for the heart at 3 minutes) and LHL 15 (=count for the liver at 15 min/ sum of the count for heart and liver at 15 minutes) were calculated as parameters. The groups were classified under the remnant liver volume and donor age, and the influence was studied.

Results: When the remnant liver volume was less than 40% of the original liver, the regeneration ratios for the remnant liver volume were 148%,164%, 176%, and 202%, HH15 values were 0.548, 0.588, 0.587, 0.526, and LHL15 values were 0.951, 0.947, 0.943, 0.956, at 1, 2, 4, and 12 weeks after hepatectomy. When the remnant liver volume was equal to or more than 40%, regeneration ratios were 116%,118%, 117%, and 137%, HH15 values were 0.438, 0.484, 0.500, 0.508, and LHL15 values were 0.947, 0.940, 0.940, 0.933, at 1, 2, 4, and 12 weeks after hepatectomy. Statistical differences were found in the regeneration ratios at all 4 points (P<0.0001), in HH15 at 1 (P<0.0001), 2 (P<0.0001), and 4 weeks (p=0.0002), and in LHL15 at 12 weeks (p=0.001). No statistical differences were found in the regeneration ratios, HH15 and LHL 15 between old and young donors.

Conclusion: In the early period after donor hepatectomy in LDLT, regardless of donor age, the smaller is the remnant liver, the higher is the regeneration ratio and the liver function is the more impaired. Thus, careful management for donors is crucial in the early postoperative period.