Shunt magnitude is a key determinant of overt hepatic encephalopathy in patients undergoing TIPS

Background & Aims: Under-dilated transjugular intrahepatic portosystemic shunts (U-TIPS) has been proposed to reduce the risk of overt hepatic encephalopathy (OHE) while effectively treating portal hypertension (PH) complications. In this study we assessed how end-procedural porto-caval pressure gradient (PCPG), obtained in sedated patients, and endoprosthesis dilation affect the risk of OHE after TIPS. Methods: Consecutive patients with cirrhosis receiving TIPS for refractory ascites or recurrent PH-related bleeding were enrolled. OHE within 1-year was analyzed using a competing risk model, accounting for death and liver transplantation. Adequate hemodynamic response (AHR) was defined as post-TIPS PCPG <12 mmHg or reduction ≥60% in refractory ascites, and <12 mmHg or reduction ≥50% in PH-related bleeding. PCPG values outside of the above criteria were considered as inadequate response. U-TIPS was defined as endoprosthesis dilation ≤7 mm, as opposed to standard TIPS (S-TIPS). Results: Among 408 patients enrolled, 50% received U-TIPS, 63% achieved AHR, and 46% had a PCPG <10 mmHg. One-year cumulative incidence of OHE was 33% and 50% in U-TIPS and S-TIPS, respectively (p <0.001). In the univariable analysis, both AHR and PCPG <10 mmHg, and S-TIPS were associated with higher cumulative incidence of OHE. In a model comprising age, previous history of OHE, TIPS indication, liver disease severity and endoprosthesis dilation, only S-TIPS along with older age, previous history of OHE and Child-Pugh class B and C, were statistically significantly associated with OHE. Subgroup analysis stratified by U-TIPS vs. S-TIPS confirmed that AHR and PCPG <10 mmHg were not associated with OHE within either TIPS group. Conclusions: The magnitude of the shunt emerges as an independent key determinant of post-TIPS OHE. Impact and implications: TIPS carries a significant risk of overt hepatic encephalopathy. Low portosystemic pressure gradient and larger shunt diameter have been reported to increase the risk of overt hepatic encephalopathy. The TIPS dilation diameter represents an independent key determinant of post-TIPS overt hepatic encephalopathy. Thus, TIPS under-dilation reduces overt hepatic encephalopathy occurrence while effectively controlling portal hypertension complications even without meeting established hemodynamic targets.