How is small-for-size syndrome (SFSS) in Living Donor Liver Transplantation (LDLT) managed?

Management of Small-for-Size Syndrome (SFSS) in Living Donor Liver Transplantation (LDLT)

The management of small-for-size syndrome in living donor liver transplantation requires a combination of preventive strategies, portal flow modulation techniques, and supportive care to optimize graft function and patient survival.

Definition and Pathophysiology

• SFSS is a serious complication following LDLT characterized by persistent portal vein hypertension and hyperperfusion of a small graft, leading to graft dysfunction 1
• The syndrome typically manifests with prolonged cholestasis, coagulopathy, ascites, and encephalopathy in the first postoperative week 2
• A graft-to-recipient weight ratio (GRWR) <0.8% is a major risk factor for developing SFSS 1

Prevention Strategies

Pre-operative Assessment and Planning

• Careful donor and recipient selection with meticulous assessment of graft volume is essential to prevent SFSS 3
• Thrombopoietin receptor agonists (avatrombopag and lusutrombopag) should be considered for thrombocytopenic patients before LDLT as they are superior to no treatment in avoiding platelet transfusion 4
• LDLT must be restricted to centers of excellence in hepatic surgery and transplantation due to the complexity of the procedure 4

Intraoperative Techniques

• Portal inflow modulation (PIM) significantly decreases the incidence of SFSS and improves one-year overall survival in patients with increased portal venous pressure and/or flow during reperfusion 5
• Surgical techniques for portal flow modulation include:
  • Portocaval shunt
  • Splenic artery ligation
  • Splenectomy 2
• Adequate outflow reconstruction is critical to prevent graft congestion, which can contribute to SFSS 3

Management of Established SFSS

Medical Management

• Initial focus should be on pharmacological therapy to modulate portal flow and provide supportive care 6
• Regular monitoring of liver function is essential:
  • Daily liver profile tests (Bilirubin, AST/ALT, INR, Platelets, Lactate) 4
  • Weekly volumetric analysis using cross-sectional imaging scans 4

Interventional and Surgical Management

• When medical management fails or condition progresses with impending dysfunction, interventional radiology (IR) and/or surgical interventions to reduce portal overperfusion should be considered 6
• The optimal timing of native liver removal in RAPID procedure (when applicable) is between 2-4 weeks following the initial stage, considering interstage GRWR >0.80% and adequate function 4

Critical Thresholds for Retransplantation

• The risk of graft loss increases dramatically with:
  • Bilirubin >10 mg/dL and INR >1.6 on postoperative day 7, or
  • Isolated bilirubin >20 mg/dL on postoperative day 14 6
• Retransplantation should be considered based on these parameters and the overall clinical situation 6

Special Considerations

• LDLT should only be considered when:
  1. It is the only therapeutic option, or
  2. Deceased donor LT is not an option, or
  3. A deceased donor organ has not become available 4
• For ethical appropriateness, the likelihood of recipient survival should be high, donor mortality risk low, and the donor must be well-informed of all risks 4
• A period of observation (approximately 3 months) before LDLT may be beneficial to evaluate tumor biological behavior in HCC patients 4

Monitoring and Follow-up

• Post-transplant portal pressure decreases rapidly, and thrombopoietin levels increase starting from day 1, with platelet counts usually reaching normal values within 2 weeks 4
• In patients with pre-transplant splenomegaly, subclinical hypersplenism may persist 4
• Conservative treatments for unresolved SFSS include:
  • Aggressive fluid balance correction for massive ascites
  • Anti-microbiological therapy to prevent or control sepsis
  • Intensive nutritional therapy 2

By implementing these comprehensive strategies, the risk of SFSS can be significantly reduced, and outcomes for LDLT patients can be optimized.