Smaller Living Donor Liver Grafts Do Not Affect Survival Rates

No significant difference in survival was seen when living donor left side liver grafts of less than 35% of the recipient's standard liver volume (SLV) were used, according to a new study.

Researchers at Shinshu University School of Medicine (Matsumoto, Japan) examined the impact of graft size on several clinical outcomes, including survival. A total of 120 adult recipients of left side liver grafts (either the left lobe alone, or the left lobe with the caudate lobe) were included in the study. Of these, 33 patients received grafts that were less than 35% of their SLV, while 87 other patients received larger grafts. The recipient and donor characteristics of the two groups were similar, except for mean pretransplant prothrombin international normalized ratio (INR) time and mean body weight, which were higher in the group that received the relatively smaller grafts. In all, the average graft volume/recipient SLV ratio was 31.8% in the smaller graft group and 42.5% in the larger graft group.

The researchers found that there were no significant differences in the postoperative serum total bilirubin levels, prothrombin time INR, daily ascites volume, or duration of postoperative hospital stay between the groups. However, the 1-year and 5-year survival rates in the group that received the smaller transplants were 80.7% and 64.2%, respectively, whereas those of the group that received the larger transplants were 90.8% and 84.9%, respectively, with no significant difference between groups. Seven deaths were logged from 1 year to 5 years post-transplantation, and the causes included stroke, recurrent liver cancer, uterine cancer, and sepsis. The study was published in the November 2009 issue of Liver Transplantation.

"Graft size was not considered to be the only cause of so-called small-for-size graft syndrome, and left side grafting appears to be the procedure of choice for adult-to-adult living donor liver transplantation because of the lower risk to donors in comparison with right lobe grafting,” concluded lead author Shinichi Miyagawa, M.D., and colleagues of the department of surgery.

With the extensive use of living donor liver grafts in adult patients, controversy over small-for-size syndrome has escalated in recent years, which remains difficult to diagnose since the symptoms seem to be multifactorial, and are neither specific nor inevitable. The occurrence of small-for-size syndrome seems to depend on a number of recipient and graft factors, as well as potential pathogenic mechanisms that include persistent portal hypertension and portal overperfusion.

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Shinshu University School of Medicine