Functional analysis of grafts from living donors. Implications for the treatment of older recipients.

OBJECTIVE: Living-related liver transplantation (LRLT) has established efficacy in children. In a larger recipient, LRLT requires the use of a small graft because of limits on the donor hepatectomy.

SUMMARY BACKGROUND DATA: The minimum graft weight required for successful transplantation has not been well established, although a characteristic pattern of graft dysfunction has been observed in our patients who receive small grafts. The authors present a clinicopathologic study of small liver grafts obtained from living donors.

METHODS: Clinical and histologic data were reviewed for 25 patients receiving LRLT. In five older recipients (small group), the graft represented 50% or less of expected liver weight, whereas in 20 others (large group), the graft represented at least 60% of expected liver weight. A retrospective analysis of graft function was conducted by analyzing clinical parameters and histology.

RESULTS: In the small group, 2 of 5 grafts (40%) were lost due to poor function, leading to one patient death (20% mortality), whereas in the large group, 2 of 20 grafts (10%) were lost due to arterial thrombosis without patient mortality. Early ischemic damage related to transplant was comparable with aspartate aminotransferase 203 +/- 23 (small group) and 290 +/- 120 (large group) at 24 hours (p = not significant). Early function was significantly decreased in the small group, with prothrombin time 18.2 +/- 2.2 seconds versus 14.8 +/- 1.6 seconds (large group) on day 3 (p = 0.034). All small group patients developed cholestasis with significantly increased total bilirubin levels at day 7 (16 +/- 5.2 mg% vs. 3.7 +/- 2.7 mg%; p = 0.021) and day 14 (12.0 +/- 7.4 vs. 1.8 +/- 0.7; p = 0.021) compared with the large group. Protocol biopsies in the small group revealed a diffuse ischemic pattern with cellular ballooning on day 7, which progressed to cholestasis in subsequent biopsies. Large group biopsies showed minimal ischemic changes. Three small group patients recovered with normal liver function by 12 weeks.

CONCLUSIONS: Clinical recovery after a small-for-size transplant is characterized by significant functional impairment associated with paradoxical histologic changes typical of ischemia. These changes apparently are due to graft injury, which can only be the result of small graft size. These findings have significant implications for the extension of LRLT to adults.