Value of plasma ammonia levels to predict hepatic encephalopathy after transjugular intrahepatic portosystemic shunt insertion

Background: Placement of a transjugular intrahepatic portosystemic shunt (TIPS) is an effective treatment for portal hypertension. Overt hepatic encephalopathy (oHE) is a complication after TIPS associated with increased morbidity. Elevated ratio of plasma ammonia (AMM) levels compared to local ULN has been associated with oHE, hepatic complications and increased mortality in patients with cirrhosis without TIPS. The role of AMM in risk stratification of post-TIPS oHE is unclear.

Methods: Patients with liver cirrhosis and TIPS placement were prospectively included. Follow-up (FU) was performed at 1, 3, 6 and 12 months after TIPS. Primary endpoint was oHE development, secondary endpoints were hepatic decompensation, infections or death/liver transplantation during one year after TIPS placement.

Results: Of 188 patients with TIPS, 148 patients with available baseline AMM levels were included. During FU, 37% (55/148) of patients developed oHE. In multivariable competing risk analysis, baseline AMM/ULN (HR 2.03 [CI 1.42-2.89], p=0.001) and FIPS score (HR 1.52 [CI 1.03-2.24], p=0.037) were independently associated with oHE. AMM at FU1 was available in 100 patients, of whom 29% (29/100) developed oHE after FU1. In multivariable competing risk analysis, AMM/ULN (HR 5.48 [CI 2.37-12.67], p<0.001), PHES (HR 0.86 [0.78-0.96], p=0.005) and FIPS (HR 3.57 [CI 1.79-7.14], p<0.001) at FU1 were independently associated with oHE after FU1. No significant association between AMM/ULN and the secondary endpoints was detected.

Conclusion: AMM levels before TIPS are independently associated with oHE after TIPS. AMM levels may serve as an additional marker for risk stratification of patients.

Publication History

Article published online:
20 January 2025