Coil-Assisted Small-Diameter Covered-Stent Shunt Reduction for Refractory Hepatic Encephalopathy After TIPS

Transjugular intrahepatic portosystemic shunt (TIPS) is a cornerstone minimally invasive therapy for complications of portal hypertension, including gastroesophageal variceal hemorrhage and refractory ascites. By creating a low-resistance intrahepatic conduit between the portal venous system and the hepatic vein or inferior vena cava, TIPS effectively lowers portal pressure. However, hepatic encephalopathy (HE) remains among the most common and clinically consequential adverse events after TIPS. Mechanistically, shunting diverts ammonia and other gut-derived neurotoxins away from hepatic detoxification, increasing systemic exposure and precipitating neuropsychiatric symptoms. The incidence of post-TIPS HE is approximately 30%, and nearly 8% of patients develop refractory hepatic encephalopathy (RHE). RHE is characterized by recurrent or persistent HE despite guideline-based medical therapy, including lactulose, rifaximin, nutritional optimization, and correction of precipitating factors. It is associated with substantial reductions in quality of life, frequent hospitalizations, and adverse outcomes related to falls, infections, and progressive malnutrition.

Management of RHE begins with optimized medical therapy-lactulose, rifaximin, dietary optimization (including appropriate protein intake), and identification and treatment of triggers. Nevertheless, a subset of patients continues to experience recurrent grade II or higher HE, prompting consideration of interventional strategies. TIPS shunt reduction is widely regarded as an effective option, yet current techniques for flow modulation have important limitations.

One approach uses adjunctive embolization: a smaller-diameter bare-metal stent is placed within the original TIPS stent to promote thrombosis between the stents and thereby restrict flow. In practice, the magnitude and durability of flow reduction can be unpredictable because flow may persist through the bare-stent interstices, and thrombus formation may be delayed or inconsistent. A second strategy is the parallel-stent technique, in which a balloon-expandable stent is deployed in parallel within the existing shunt to reduce the effective lumen diameter. This method often requires dual venous access (jugular and femoral), increasing procedural complexity, time, and access-related risk, which limits broader applicability. A third category includes constrained stents, either manually modified or commercially preconstrained. Handmade techniques commonly create a suture-induced "waist" in a covered stent; however, the location and degree of constriction are operator dependent and may change after deployment, raising concerns about excessive restriction and rebound portal hypertension. Commercial constrained stents improve standardization but still offer limited post-deployment adjustability. Collectively, these approaches reflect a persistent trade-off between procedural simplicity and hemodynamic control, underscoring the need for a more standardized, predictable, single-access strategy for shunt flow reduction.

To address these unmet needs, we developed a coil-assisted small-diameter covered-stent shunt-reduction technique for patients with RHE after TIPS. The procedure entails placement of a 10-mm coil within the existing TIPS to serve as an anchoring scaffold, followed by deployment of a 6-mm covered stent to achieve controlled reduction in shunt caliber and flow. We hypothesize that this approach can mitigate post-TIPS HE while maintaining an acceptable safety profile.

To test this hypothesis, we designed a single-center ambispective (bidirectional) cohort study. The retrospective cohort includes patients treated between October 2025 and August 2026, and the prospective cohort will enroll patients receiving the same intervention from September 2026 onward, with standardized follow-up. Efficacy and safety outcomes-including HE severity and recurrence, stent patency, portal hypertension-related complications, changes in portal pressure gradient, liver function parameters, transplant-free survival, and procedure-related adverse events-will be systematically evaluated.