“
“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 SP600125 in vitro 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 Cell Cycle inhibitor 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 Molecular motor 1). From our point of view, following the two hypotheses derived from this theory would decrease HE risk after TIPS procedure: 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.