How do you assess and manage liver function in patients with compromised liver function?

Assessment and Management of Liver Function in Patients with Compromised Liver Function

Pre-operative evaluation of functional liver remnant (FLR) volume and function is paramount before any major liver resection, with inadequate FLR being the most important modifiable predictor of post-hepatectomy liver failure (PHLF) and mortality. 1

Assessment of Liver Function and Volume

Volumetric Assessment

• Calculate FLR volume using CT or MRI imaging with 3-dimensional reconstruction software to assess total liver volume (TLV), FLR, and tumor volume (TV) 1
• Subtract tumor volume from TLV to obtain functional liver volume (FLV), which provides more accurate measurement for determining need for optimization 1
• Critical volume thresholds for safe resection:
  • Normal liver: FLR must be ≥20% of TLV 1
  • Chemotherapy-treated liver: FLR must be ≥30% of TLV 1
  • Cirrhotic liver: FLR must be ≥40% of TLV 1

Functional Assessment

• Perform indocyanine green (ICG) clearance test (ICG-R15) as the most commonly used functional assessment 1, 2
• ICG-R15 >15-20% indicates impaired hepatic functional reserve and necessitates volume optimization strategies 1, 2
• For cirrhotic patients, limit resection to those with ICG-R15 <20-25% and segmentectomy to those <30-35% 2
• Consider percutaneous or transjugular liver biopsy of the FLR when extent of parenchymal disease is unclear 1

Laboratory Markers

• Recognize that standard liver function scores (MELD, Child-Pugh) may not accurately reflect function in all contexts 1
• In patients with cirrhosis (Child-Pugh B or C) and portal hypertension, even small resections can result in PHLF 1
• Progressive thrombocytopenia may indicate advanced fibrosis and hypersplenism from portal hypertension 1
• Elevated INR in non-cirrhotic patients may reflect passive congestion rather than synthetic dysfunction 1

Management Strategies for Inadequate FLR

Portal Vein Embolization (PVE) - First-Line Strategy

• PVE is the most widely used and safest volume optimization strategy, technically feasible in >90% of patients with low complication risk 1
• Redirects portal flow to FLR, causing hypertrophy that increases volume by 40-62% after median 34-37 days 1
• Up to 80% of patients successfully undergo planned resection after PVE 1
• Indicated for patients requiring extensive resection with borderline or insufficient FLR volume 1

Alternative Volume Optimization Strategies

• Portal vein ligation (PVL) with two-stage hepatectomy can be considered but has similar outcomes to PVE 1
• Yttrium-90 radioembolization is an option for select patients 1
• ALPPS (associating liver partition and portal vein ligation) should be avoided due to significantly higher morbidity (73% vs 59%) and mortality (14% vs 7%) compared to PVE, despite faster hypertrophy 1

Management of Post-Hepatectomy Liver Failure (PHLF)

Supportive Care Approach

• Focus on providing support to the struggling liver, minimizing hepatic insult, and maintaining end-organ function rather than therapeutic interventions 1
• Apply same treatment strategies used for acute liver failure, acute-on-chronic liver failure, and sepsis 1

Specific Interventions

• For acetaminophen-associated acute liver failure, use N-acetyl cysteine (NAC) 1
• For non-acetaminophen-associated acute liver failure, NAC should only be used in clinical trials 1
• Plasma exchange is NOT recommended for routine use in acute-on-chronic liver failure outside research trials, except as bridge to transplantation in highly selected critically ill patients when standard therapies fail 3

Transplantation Considerations

• Rescue hepatectomy and liver transplantation are options for select PHLF patients meeting transplant criteria 1
• Liver transplantation is generally contraindicated in metastatic hepatic disease, except select patients with metastatic neuroendocrine tumors 1

Critical Pitfalls to Avoid

• Never proceed with major hepatectomy without pre-operative volumetric and functional assessment 1
• Avoid ALPPS procedure given its significantly higher mortality compared to PVE 1
• Do not rely solely on standard liver function tests (aminotransferases, bilirubin) as they may be normal despite compromised function 1
• Avoid excessive and prolonged venous inflow occlusion in cirrhotics with borderline FLR 1
• Do not use plasma exchange routinely for acute-on-chronic liver failure outside clinical trials 3