Predicting post-TIPS hepatic encephalopathy risk in patients with cirrhosis and refractory ascites: a proof-of-concept study using a 4D MRI perfusional model

Background

Transjugular intrahepatic portosystemic shunt (TIPS) is a well-established treatment for refractory ascites (RA) in patients with cirrhosis. However, a major drawback is the development of post-procedural hepatic encephalopathy (HE), which results from the diversion of blood from the portal vein. According to the first-pass effect, this diversion reduces the liver's capacity to metabolize substances from the gut, leading to an accumulation of toxic compounds in the brain. Given that liver perfusion relies on arterial compensation (hepatic arterial buffer), it is plausible that effective compensation, which also depends on cardiac function, may reduce the risk of encephalopathy by detoxifying the blood during the second-pass metabolism.

Aims

To evaluate by Dynamic Contrast Enhanced-Magnetic Resonance Imaging (DCE-MRI) the changes in liver perfusion induced by TIPS in patients with RA and their relationship with the risk of HE.

Materials

Twenty-nine consecutive patients underwent DCE-MRI, cardiac and hepatic hemodynamic evaluation before and after TIPS. MRI images were processed by a homemade software using the Dual Input Dual Compartment (DIDC) model, focusing on perfusion parameters.

Results

The DIDC model showed that total hepatic perfusion decreased by 24% after TIPS (248 ml/min/100ml vs 189 ml/min/100ml, p 0.095). As expected, a significant reduction in portal perfusion (decreased by 67%; 128.6 ml/min/100ml vs 42.4 ml/min/100ml, p 0.004) and an increase in hepatic arterial fraction post-TIPS (48% vs 77%, p 0.001) was observed. Post-TIPS residual total hepatic perfusion inversely correlated with one-year HE risk: patients with perfusion ≤ 130 ml/min/100ml had a HE risk of 67.6% vs 36.4% for those > 130 ml/min/100ml (HR: 2.1, p 0.039).

Conclusion

Perfusion MRI is able to elucidate the impact of TIPS on liver perfusion, quantifying the extent of hepatic perfusion and its correlation with the development of post-TIPS HE.