Impact of graft size mismatching on graft prognosis in liver transplantation from living donors

Background. Although living donor liver transplantation for small pediatric patients is increasingly accepted, its expansion to older/larger patients is still in question because of the lack of sufficient information on the i mpact of graft size mismatching. Methods. A total of 276 cases of living donor liver transplantation, exclud ing ABO-incompatible, auxiliary, or secondary transplants, were reviewed fr om graft size matching. Forty-three cases were highly urgent cases receivin g intensive care preoperatively. Cases were categorized into five groups by graft-to-recipient weight ratio (GRWR): extra-small-for-size (XS; GRWR<0.8 %, 17 elective and 4 urgent cases), small (S; 0.8 less than or equal to GRW R<1.0%, 21 and 7), medium (M; 1.0 less than or equal to GRWR<3.0%, 119 and 19), large (L; 3.0 less than or equal to GRWR<5.0%, 67 and 10), and extra-l arge era; GRWR greater than or equal to 5.0%, 9 and 3). Results. Smaller-for-size grafts were associated not only with larger and o lder recipients, but also with rather older donors. Posttransplant bilirubi n clearance was delayed and aspartate aminotransferase corrected by relativ e graft size was higher in XS and S. Posttransplant hemorrhage and intestin al perforation were more frequent in XS and S, and vascular complications a nd acute rejection were more frequent in larger-for-size grafts. Consequent ly, graft survival in XS (cumulative 58% and actuarial 42% at 1 year) and S (76% and 74%) was significantly lower compared with that in M (93% and 92% ) in elective cases. Graft survival in L (83% and 82%) and XL (75% and 71%) did not reach statistical significance. Conclusions. The use of small-for-size grafts (less than 1% of recipient bo dy weight) leads to lower graft survival, probably through enhanced parench ymal cell injury and reduced metabolic and synthetic capacity. Although lar ge-for-size grafts are associated with some anatomical and immunological di sadvantages, the negative impact is less pronounced.