What are the criteria for Enhanced Liver Volume Recovery (ELVR)?

Criteria for Enhanced Liver Volume Recovery (ELVR)

Enhanced Liver Volume Recovery (ELVR) requires a minimum future liver remnant (FLR) of ≥20% in healthy livers, 30-35% in mild liver disease, and 40-50% in severe liver disease or cirrhosis, with volume optimization strategies indicated when these thresholds are not met. 1

Assessment of Liver Volume and Function

Volumetric Assessment

• Total liver volume (TLV), future liver remnant (FLR), and tumor volume (TV) must be calculated using imaging modalities:
  • CT scan or MRI with 3D reconstruction software is preferred
  • Functional liver volume (FLV) = TLV - TV (provides more accurate measurement) 1
  • Right liver typically accounts for ~65% of total volume (range 49-82%)
  • Left liver typically accounts for ~35% of total volume (range 17-49%)

Minimum FLR Requirements

1. Normal liver parenchyma: FLR ≥20% 1
2. Compromised liver:
   • Mild steatosis, cholestasis, early cirrhosis (Child's-Pugh A): 30-35% 1
   • Severe steatosis and cholestasis: 40% 1
   • Advanced cirrhosis (Child's-Pugh B/C) or portal hypertension: 50% 1

Functional Assessment

• Indocyanine green (ICG) clearance test:
  • ICG retention rate at 15 minutes (ICGR15) >15-20% indicates impaired hepatic functional reserve 1
  • Requires volume optimization strategies when elevated
• Liver stiffness measurement (LSM):
  • Values above 12-14 kPa predict significant risk of post-hepatectomy liver failure 1
  • Can be used to estimate safe liver remnant volume

Volume Optimization Strategies

When FLR is insufficient, the following strategies can be implemented:

Portal Vein Embolization (PVE)

• Most widely used strategy with technical feasibility in >90% of patients 1
• Mechanism: Occludes portal venous flow to the side requiring resection, redirecting flow to FLR
• Results:
  • FLR volume typically increases by 40-62% after 34-37 days 1
  • Up to 80% of patients become eligible for planned resection
• Criteria for proceeding with resection after PVE:
  • FLR hypertrophy >5% in patients with normal liver 1
  • FLR hypertrophy >10% in patients with severe liver disease 1
  • Resection typically performed 4-6 weeks after PVE 1

Yttrium-90 (Y90) Radioembolization

• Alternative approach that provides both FLR hypertrophy and tumor control
• Particularly useful in hepatocellular carcinoma patients
• Provides approximately 30% FLR hypertrophy 1

Monitoring Post-Hepatectomy Liver Failure Risk

50-50 Criteria

• Prothrombin index <50% (INR >1.7)
• Serum bilirubin >50 μmol/L (2.9 mg/dL) on postoperative day 5
• When met, indicates 59% risk of mortality 1

ISGLS Grading System

• Grade A: No change in clinical management required
• Grade B: Change in clinical pathway but no invasive treatment needed
• Grade C: Invasive procedure required
• Mortality risks: Grade B (12%), Grade C (54%) 1

Enhanced Recovery Protocols

Implementation of Enhanced Recovery After Surgery (ERAS) protocols improves outcomes after liver surgery:

• Reduces length of hospital stay 2
• Decreases postoperative complications 2
• Improves patient-reported outcomes 3
• Accelerates return to baseline functional status 3
• Increases likelihood of returning to intended oncologic therapy (95% vs 87%) 3

Common Pitfalls and Caveats

1. Underestimating liver disease severity: Always assess underlying liver disease thoroughly before determining FLR requirements.

2. Relying solely on volume: Volume is a surrogate for function; functional assessment with ICG or LSM provides complementary information 1.

3. Inadequate waiting time after PVE: Rushing to surgery before adequate hypertrophy (4-6 weeks) increases risk of post-hepatectomy liver failure 1.

4. Neglecting portal hypertension: Even with adequate FLR, clinically relevant portal hypertension significantly impacts outcomes 1.

5. Overlooking patient-specific factors: Age, comorbidities, and nutritional status all affect recovery and should be considered in the assessment.