Two hypotheses for decreasing hepatic encephalopathy risk after transjugular intrahepatic portosystemic shunt
Authors: Ming Bai, Guohong Han, Xingshun Qi, Zhanxin Yin, Daiming Fan
Journal: Hepatology (2009)

We read with great interest the 2009 update of the American Association for the Study of Liver Diseases Practice Guideline.1 Boyer and Haskal did not recommend the prophylactic use of nonabsorbable disaccharides or antibiotics to decrease the episodes of hepatic encephalopathy (HE) in patients with cirrhosis after transjugular intrahepatic portosystemic shunt (TIPS). Probably, the power of abandoning the prophylactic use of this two series of oral drugs in patients after TIPS procedure is not strong enough based on the only research about this subject conducted by Riggio et al.2 The reason is the small sample size (25 per group) which was caused by too high an expected effect (40% versus 10%) of pharmacological treatments in their trial. It is well known that small sample size would lead to a poor representative conclusion easily disturbed by various errors. In 2009, Sharma et al.3 and Neff et al.4 reported lactulose was effective in preventing recurrence of HE (19.6% versus 46.8%) and rifaximin was effective in reducing the HE-related hospitalizations (16% versus 26%), respectively. The main difference between patients with HE who had or had not undergone TIPS procedure is a newly created shunt which bypasses splanchnic blood from portal vein to systemic circulation in HE patients with TIPS. However, the neurotoxins derived from gut, such as ammonia, affect patients with HE both with and without TIPS procedure. Nolte et al.5 reported that the HE rate declined to the level before TIPS despite the higher arterial ammonia level beyond 3 months, which was explained tentatively by the adaptability of the brain. Although the HE rate was high after TIPS, only about 5% could not tolerate the shunt, resulting in refractory HE.6 This phenomenon somewhat verified the cerebral adaptability theory. Furthermore, the patients who accepted a TIPS procedure in our center in 2008 demonstrated early HE episode (≤40 days), which could be partially explained by cerebral adaptability as well (Table 1). Decrease post-TIPS portosystemic gradient step by step. The linchpin for this process is an adjustable stent system of which the radius could be adjusted ad libitum. An adjustable stent system will assist clinicians in achieving an accurate post-TIPS portosystemic gradient, which should be lower than 12 mmHg6 or 25%–50% of the pre-TIPS portosystemic gradient.7 In expectation of this, an adjustable stent system should be designed in the near future. Reduce splanchnic blood flow and gut-derived neurotoxins to the lowest levels and then raise them step by step (Fig. 1). Absolutely, this theoretical prophylactic treatment should be confirmed by randomized controlled trials before guiding our work. A combination of diet-control with drugs to decrease HE risk after TIPS procedure. Finally, we suggest that large sample size trials should be conducted to confirm the effect of the prophylactic use of antibiotics and nonabsorbable disaccharides in patients after TIPS procedure. Furthermore, diet-control combined with the aforementioned drugs is probably a viable way to decrease HE risk after TIPS, and a novel adjustable stent system will improve the maneuverability of TIPS procedure. We are grateful to Ms. Jing Niu and technician Wengang Guo for data collection and helpful discussions. Ming Bai*, Guohong Han*, Xingshun Qi*, Zhanxin Yin*, Daiming Fan , * Department of Digestive Interventional Radiology, Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China, State Key Laboratory of Cancer Biology, Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China.