Comparison of Underdilated Versus Standard Transjugular Intrahepatic Portosystemic Shunt in Preventing Rebleeding From Esophagogastric Varices in Patients With Cirrhosis in Chinese Tertiary Hospitals: Protocol for a Multicenter Randomized Controlled Trial

Transjugular intrahepatic portosystemic shunt (TIPS) is a pivotal intervention for managing complications of portal hypertension. However, its clinical utility is limited by the risk of post-procedural hepatic encephalopathy (HE).

The pathogenesis of post-TIPS HE involves two principal mechanisms: the diversion of portal venous blood flow away from the liver and a concurrent reduction in hepatic metabolic capacity. Following TIPS placement, portal venous blood is shunted directly into the systemic circulation, resulting in decreased functional hepatic perfusion. This hemodynamic alteration not only increases the risk of HE but may also exacerbate pre-existing hepatic dysfunction. Evidence suggests that stent diameter plays a critical role in determining shunt patency, efficacy of portal pressure reduction, and the incidence of HE. A stent that is too narrow may inadequately lower portal pressure, leading to suboptimal therapeutic outcomes and an increased risk of shunt stenosis. Conversely, an excessively large stent can substantially increase the risk of HE and further impair liver function. Therefore, identifying an optimal stent diameter that effectively reduces portal pressure while minimizing complications-particularly shunt-induced HE-remains a central focus in TIPS research, aiming to balance procedural efficacy with safety to improve patient outcomes.

Early studies demonstrated that the use of stents with larger diameters than conventional calibers for the portal and hepatic veins was associated with a disproportionately increased risk of hepatic encephalopathy (HE) without substantial additional benefit in portal pressure reduction. Consequently, a stent diameter of 10 mm became the standard during the era of bare metal stents. However, the introduction of polytetrafluoroethylene (PTFE)-covered stents has significantly reduced the incidence of shunt dysfunction and improved the durability of portal pressure reduction following transjugular intrahepatic portosystemic shunt (TIPS) placement. Clinical evidence indicates that 8 mm PTFE-covered stents can maintain long-term patency and achieve adequate portal decompression while substantially lowering the risk of HE. Despite these advancements, the overall incidence of post-TIPS HE remains high, approximately 30%. To further optimize clinical outcomes, recent studies have explored a "stent underdilation" strategy, involving dilation of an 8 mm PTFE-covered stent using a 6 mm balloon. Preliminary data suggest that this approach may further reduce the incidence of HE without significantly increasing the risk of recurrent portal hypertensive events. Nevertheless, there is currently a lack of prospective, head-to-head randomized controlled trials comparing the efficacy and safety of underdilated TIPS versus standard-diameter TIPS in the management of complications related to portal hypertension.

In the context of managing gastroesophageal variceal bleeding, the established therapeutic goal of TIPS is to reduce the portosystemic pressure gradient (PPG) to less than 12 mmHg (16 cmH₂O). Building upon this principle, the investigators propose the following hypothesis: in patients with esophagogastric variceal bleeding undergoing TIPS, underdilated TIPS will reduce the incidence of overt HE and attenuate liver function deterioration without increasing the risk of rebleeding. To evaluate this hypothesis, the investigators have designed the present prospective clinical trial.