Role of Plasmapheresis in ALF and ACLF

Comprehensive Summary: Role of Plasmapheresis in Acute Liver Failure (ALF) and Acute-on-Chronic Liver Failure (ACLF)

Lecturer: Nikolaos Pyrsopoulos

1. Main Clinical Topics Discussed

• Pathophysiology of systemic inflammation in ALF and ACLF
• Mechanism and technique of therapeutic plasma exchange (TPE) / plasmapheresis
• Historical development of plasmapheresis in liver failure
• Evidence base for high-volume plasma exchange (HVPE) in ALF
• Role of TPE as a bridge to liver transplantation

2. Key Learning Points, Guidelines, and Recommendations

Pathophysiology:

• Hepatic injury triggers release of damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs)
• Gut barrier dysfunction and bacterial translocation perpetuate systemic inflammation via the portal circulation
• Activated immune cells produce pro-inflammatory cytokines: IL-6, IL-1β, IL-8, TNF-α
• Cytokine levels correlate directly with the number of organ failures
• Once the inflammatory cascade is initiated, it becomes self-perpetuating — even after the primary insult is treated
• Downstream consequences include: acute kidney injury (AKI), cardiac dysfunction, cerebral edema, and multi-organ failure

Mechanism of Therapeutic Plasma Exchange:

• Separates plasma from blood via centrifugation or membrane filtration
• Removes albumin-bound and water-soluble toxins including:

- Inflammatory cytokines

- Endotoxins

- Bilirubin, bile acids, ammonia, aromatic amino acids

• Replaces removed plasma with fresh frozen plasma (FFP) and/or albumin
• Albumin functions as a molecular "sponge," transporting inflammatory cytokines

Clinical Indications:

• ALF and ACLF where underlying cause has been treated but inflammatory cascade persists
• Bridge to liver transplantation when grafts are unavailable or access is limited
• Patients with contraindications to transplantation

Pre-Procedure Workup Required:

• Biochemistry, CBC, coagulation studies
• Infection screening
• Blood type and crossmatch
• Total plasma volume calculation (Netherlands formula; sex-specific)

Technical Considerations:

• Calculate total plasma volume prior to procedure
• Determine session volume and frequency
• Ensure adequate vascular access
• Plan anticoagulation strategy
• Replenish immunoglobulins (IVIg) as needed, given antibody removal
• Monitor biochemistry, CBC, and coagulation throughout

3. Specific Clinical Data, Statistics, and Study Results Cited

Landmark RCT — Larsen et al., 2016 (Journal of Hepatology):

*"High-Volume Plasma Exchange in Patients with Acute Liver Failure"*

• Design: Prospective, open-label, randomized, multicenter controlled trial
• Population: 182 patients with ALF (90 standard medical therapy [SMT]; 92 SMT + HVPE)
• HVPE Definition: Exchange of 8–15% of ideal body weight using FFP per session
• Patient profile: Predominantly female, mean age ~45 years; etiologies included acetaminophen/paracetamol toxicity, acute viral hepatitis, toxic hepatitis, and cryptogenic causes
• Mean plasma exchanges per patient: 2.4 sessions
• Mean plasma volume exchanged (first session): ~9 liters

Key Outcomes:

• Transplant-free survival to hospital discharge: 58.7% (HVPE) vs. 47% (SMT)
• Hazard ratio: 0.56 (statistically significant, favoring HVPE)
• Survival curves diverged significantly by Day 7 and were maintained to Day 80–90
• Renal replacement therapy requirement: 47% (HVPE) vs. 68% (SMT) — statistically significant reduction
• Mean arterial pressure improved significantly in the HVPE group
• SOFA scores decreased significantly from Day 2 onward in the HVPE group
• **Pro-inflammatory cytokines