Postoperative changes in remnant medial segment parenchyma of living donor livers after procurement of left lateral segment graft.

Background/aims: Procurement of left lateral segment (LLS) graft usually resulted in uneventful atrophy of the remnant medial segment parenchyma (RMSP) in living donors, but duct dilatation was often detected in the RMSP. We tried to clarify the postoperative atrophic sequences of the RMSP.

Methodology: We analyzed clinical profiles of 33 LLS graft donors out of 362 living donors from January 2002 to December 2003. LLS grafts were divided into type 1 (classical LLS, n= 18), type 2 (intermediately extended LLS, n=8), and type 3 (extended LLS similar to left lobe without middle hepatic vein trunk, n= 7).

Results: On 1-week dynamic computed tomography, early extensive hyperattenuation indicating interlobar arterial collaterals (ILAC) was observed in 4 (22.2%) donors of type 1 and 2 (25%) donors of type 2 LLS grafts. Peak values of serum liver enzymes were not correlated with the amount of RMSP, but they were exceptionally elevated on poor development of ILAC. Most of RMSP became atrophied within 3 months. Delayed-onset bile leak occurred in a donor, by which we had to resect his functional RMSP after 3 months. ILAC was highly associated with persistent bile production and slow atrophic change at RMSP after LLS graft donation.

Conclusions: These data suggested that temporary arterial collateral formation worked as a buffering mechanism leading to slow and uneventful degeneration of inflow-deprived hepatic parenchyma.