Acute Kidney Injury in Cirrhosis: Implications on Liver Transplantation by Prof. Pratima Sharma, MD

Acute Kidney Injury in Cirrhosis: Implications on Liver Transplantation

Summary of Lecture by Prof. Pratima Sharma, MD

1. Main Clinical Topics Discussed

• Diagnosis and staging of acute kidney injury (AKI) in cirrhosis
• Limitations of serum creatinine and GFR estimation in cirrhotic patients
• Pathophysiology of hepatorenal syndrome (HRS)
• Classification and updated diagnostic criteria for HRS-AKI
• Management approach to AKI in cirrhosis
• Impact of AKI phenotype on transplant candidacy and outcomes

2. Key Learning Points, Guidelines, and Recommendations

Limitations of Creatinine in Cirrhosis:

• Serum creatinine underestimates true renal dysfunction in cirrhosis due to decreased muscle mass, poor nutrition, and reduced hepatic synthetic function
• All standard GFR equations (CKD-EPI, MDRD, Brøcker) overestimate measured GFR, particularly when true GFR <60 mL/min
• Cystatin C-based equations underestimate GFR; creatinine-based equations overestimate
• Adjunct biomarkers (Cystatin C, NGAL) should complement serum creatinine

AKI Staging (Modified RIFLE Criteria):

• Stage 1: Serum creatinine rise >0.3 mg/dL within 48 hours or 1.5–2× baseline

- Stage 1a: Peak creatinine <1.5 mg/dL

- Stage 1b: Peak creatinine ≥1.5 mg/dL

• Stage 2: 2–3× rise from baseline (potentially reversible)
• Stage 3: >3× rise from baseline or initiation of renal replacement therapy (RRT)

Updated AKI Definition (ADQI/ICA Joint Consensus):

• Rise in serum creatinine >0.3 mg/dL within 48 hours, or >50% from baseline within 7 days, or urine output <0.5 mL/kg/hr for >6 hours
• Baseline creatinine: use value from prior 3 months (closest to admission); if unavailable, extend to 12 months

HRS Diagnostic Criteria:

• Requires cirrhosis with ascites
• No response after 2 days of diuretic withdrawal and albumin expansion (1 g/kg/day)
• Absence of shock, nephrotoxic drugs, or structural kidney injury (no proteinuria, hematuria, normal ultrasound)
• Absence of alternative explanation for AKI
• Updated criteria allow HRS diagnosis in patients with pre-existing CKD

Updated HRS Nomenclature:

• Former HRS Type 1 → now HRS-AKI (rapid, severe, poor prognosis)
• Former HRS Type 2 → now HRS non-AKI, subdivided into:

- HRS-AKD (acute kidney disease): eGFR <60 mL/min for <3 months, no structural damage

- HRS-CKD: duration >3 months

3. Specific Clinical Data and Study Results Cited

• Meta-analysis (25 studies, ~400 patients, median age 52, 37% female): All GFR equations overestimate when measured GFR <60 mL/min; CKD-EPI Cystatin C overestimates by ~10.3 mL/min, Brøcker by ~12.6 mL/min, MDRD6 by ~15.7 mL/min
• AKI prevalence in cirrhosis: 47–53% in published cohorts; HRS incidence ranges 12–32%
• Multinational prospective cohort (decompensated cirrhosis): Of 1,456 AKI patients, >50% had Stage 1 AKI; 20% had Stage 3; Stage 2/3 AKI associated with 50% survival at 30 days and 36% at 90 days
• **Study of 263 A