Portal flow modulation in living donor liver transplantation: review with a focus on splenectomy

Abstract

Small-for-size graft (SFSG) syndrome after living donor liver transplantation (LDLT) is the dysfunction of a small graft, characterized by coagulopathy, cholestasis, ascites, and encephalopathy. It is a serious complication of LDLT and usually triggered by excessive portal flow transmitted to the allograft in the postperfusion setting, resulting in sinusoidal congestion and hemorrhage. Portal overflow injures the liver directly through nutrient excess, endothelial activation, and sinusoidal shear stress, and indirectly through arterial vasoconstriction. These conditions may be attenuated with portal flow modulation. Attempts have been made to control excessive portal flow to the SFSG, including simultaneous splenectomy, splenic artery ligation, hemi-portocaval shunt, and pharmacological manipulation, with positive outcomes. Currently, a donor liver is considered a SFSG when the graft-to-recipient weight ratio is less than 0.8 or the ratio of the graft volume to the standard liver volume is less than 40%. A strategy for transplanting SFSG safely into recipients and avoiding extensive surgery in the living donor could effectively address the donor shortage. We review the literature and assess our current knowledge of and strategies for portal flow modulation in LDLT.

Post-transplant inflow modulation for early allograft dysfunction after living donor liver transplantation

“…Moreover, recent studies have documented that GRWR less than 0.8% or GV/SLV less than 40% do not necessarily lead to SFSS [15][16][17][18][19]. Indeed, multiple variables are attributed including preoperative recipient disease severity, donor age, portal pressure and/or flow, graft type, and graft regeneration [3,17,20,21].…”

“…Indeed, secondary ischemic changes occur due to adaptive hepatic artery vasoconstriction [27]. A key management strategy is portal flow modulation with partially diverting portal flow via portosystemic shunt [28] and/or portal decompression by splenectomy [3,29,30], splenic artery ligation [29,31], or splenic artery embolization [7,32,33]. Following LDLT, maintaining adequate portal inflow is crucial for boosting graft regeneration [34].…”

“…Small-for-size syndrome (SFSS) can lead to serious early graft dysfunction after LDLT. The main clinical presentation is cholestasis, prolonged ascites, coagulopathy, and encephalopathy [3]. Extra small graft, portal hyperperfusion, severe portal hypertension, and venous outflow obstruction are the main underlying causes of SFSS [4].…”

Is Splenectomy Always Effective on Liver Regeneration of Extended Left Lobe Graft After Living Donor Liver Transplantation?

“…Splenectomy is a well-known procedure in LDLT to improve thrombocytopenia in patients with HCVrelated liver cirrhosis and for immunomodulation in ABO-incompatible cases (1). Also, splenectomy can be used to reduce the portal venous flow in the case of small-for-size graft LDLT (2).…”

“…Splenectomy is a well-known procedure in living donor liver transplantation (LDLT) to modulate portal venous flow, improve thrombocytopenia in patients with HCV-related liver cirrhosis, and for immunomodulation in ABO-incompatible cases (1,2). However, the effect of splenectomy on liver volume increase of a partial graft after LDLT is controversial.…”