Transient portocaval shunt for a small-for-size graft in living donor liver transplantation

Abstract

We read with interest the article by Taniguchi et al. from Hokkaido University.1 They proposed the usefulness of transient portocaval shunt, closed with an endoloop, for the management of small-for-size graft syndrome in living donor liver transplantation (LDLT). Although we appreciated their tactful technique for shunt closure without laparotomy, we do not, however, agree with its universal application in LDLT using small grafts. There have been several concepts reported for the management of small-for-size graft syndrome in LDLT. A simple way is to increase the graft volume by the application of right-lobe LDLT or auxiliary LDLT.2, 3 Another way is decompression of the excessive portal pressure and flow into a small graft. This includes the formation of a portocaval shunt or performing splenectomy or splenic artery ligation.1, 4 As described in their report, the dilemma in the application of a portacaval shunt is that it itself may jeopardize the graft regeneration.1 The systemic venous pressure is always lower than the portal system pressure, and graft regeneration would still increase the intragraft portal pressure. It may possibly cause graft nonfunction caused through the decreased graft portal flow by a stealing mechanism. As we have previously reported, splenectomy or splenic artery ligation is a simple concept for decompression of portal hypertension. With these maneuvers, portal pressure can always be pulled down to around 20 cm H2O.4 The hemodynamic status over the recipient's posttransplant time course and the graft is much simpler in splenectomy or splenic artery ligation than in a portacaval shunt, which might need manual closure in association with graft regeneration.1 The positive points of a splenectomy include not only the decompression of portal hypertension but also increased leukocyte and platelet counts.4 Moreover, the surgical techniques for splenectomy have improved dramatically with the recent introduction of a vessel sealing system.5 Our indication for establishing a portocaval shunt is limited only by portal system pressure greater than 20 mm Hg after the performance of splenectomy or splenic artery ligation. Moreover, the graft volume/standard liver volume (GV/SLV) ratio described in the report by Taniguchi et al.1 is 35.8%. As we previously reported, our key GV/SLV value for the choice of graft is 35%.2 If the GV/SLV is less than 35% in the left-lobe graft, the right-lobe graft is chosen. However, several cases in our series eventually had GV/SLV < 30% with a 1-year graft survival of 80%.2 Thus, we question why they needed to perform temporary portacaval shunt for that case. Indeed, what are the details of their indication of temporary portacaval shunt? We would have just performed splenectomy for that GV/SLV = 35.6% case and might have undertaken a portacaval shunt if the portal pressure after splenectomy had been greater than 20 mm Hg. Toru Ikegami*, Satoru Imura*, Yusuke Arakawa*, Mitsuo Shimada*, * Department of Surgery, University of Tokushima, Kuramoto-cho Tokushima, Japan.