Changes in liver and spleen volumes after living liver donation: A report from the Adult-to-Adult Living Donor Liver Transplantation Cohort Study (A2ALL)

摘要

Previous reports have drawn attention to persistently decreased platelet counts among liver donors. We hypothesized an etiologic association between altered platelet counts and post-donation splenomegaly and sought to explore this relationship. This study analyzed de-identified CT/MR scans of 388 donors from 9 A2ALL centers read at a central computational image analysis lab. Resulting liver and spleen volumes were correlated with time-matched clinical lab values. Pre-donation liver volumes varied twofold in healthy subjects, even when normalized by body surface area (BSA) (range: 522 – 1887cc/m², N=346). At 3 months post-donation liver volumes were, on average, 79% of pre-donation volumes (IQR: 73-86%, N=165) and approached 88% at 1 year (IQR: 80-93%, N=75). The mean spleen volume pre-donation was 245 cc (N=346). Spleen volumes greater than 100% of pre-donation volume occurred in 92% of donors at 3 months (N=165) and 88% at 1 year post-donation (N=75). We sought to develop a standard spleen volume (SSV) model to predict “normal” spleen volumes in donors pre-donation and found that decreased platelet counts, younger age, higher pre-donation liver volume, higher hemoglobin and higher BSA predicted a larger spleen volume (N=344, R²=0.52). When applied to post-donation values some large volumes were under predicted by the SSV model. Models developed on the reduced sample of post-donation volumes yielded smaller under-predictions. These findings confirm previous observations of thrombocytopenia associated with splenomegaly post-donation. The results of the SSV model suggest the biology of this phenomenon is complex. This merits further long term mechanistic studies of liver donors with investigation into the role of other factors such as thrombopoietin, and exposure to viral infections to better understand the evolution of spleen volume after liver donation.