A recent case report by Xiao et al. provides a good example of the potential for misunderstanding regarding the recognition of small-for-size syndrome (SFSS).
In SFSS, a graft with a suboptimal hepatic parenchyma mass failing to meet the metabolic burden results in prolonged cholestasis, coagulopathy, and persistent ascites. Criteria from Zurich, Switzerland and Fukuoka, Japan have been widely adopted. Failed vascular anastomoses, infections, and rejection are considered exclusionary. A graft/recipient weight ratio less than 0.8% or a graft/standard liver volume ratio less than 40% is the cutoff.[2, 4] The role of portal flow modulation in preventing SFSS remains controversial.[5, 6]
Xiao et al.'s report of a patient with a graft weighing 615 g (with a graft/standard liver volume ratio of 47.5% and a graft/recipient weight ratio of 0.85%) who was diagnosed with SFSS and was subsequently treated with a transjugular intrahepatic portosystemic shunt cannot be readily accepted as a case of SFSS. Although this graft was much lower in volume than the whole liver grafts available for deceased donor liver transplantation, many centers that perform living donor liver transplantation in Asia will accept a graft/standard liver volume ratio of 47.5% as sufficient with the expectation of an uneventful postoperative course.
Before proceeding with a discussion of the role of a transjugular intrahepatic portosystemic shunt in SFSS, we must first question the diagnosis of SFSS in this particular case. Anatomic complications require strict exclusion, and the quality of the graft should be further evaluated. We may learn more from the following information: the patency of the suprahepatic vein and tributaries from the anterior segment and details about the donor's liver function before donation and the pathological evaluation (eg, Masson's trichrome staining).
At present, caution must be taken before the authors' interpretation of this particular case is universally accepted.