Chapter 18: Transjugular Intrahepatic Portosystemic Shunt Reduction for Post-TIPS Hepatic Encephalopathy Hepatic encephalopathy (HE) is a known complication of transjugular intrahepatic portosystemic shunt (TIPS) creation. The most widely used system for grading the severity of HE is the West Haven criteria ( Ligation of surgically created portosystemic shunts was reported by Hanna et al in 1981 for the treatment of HE refractory to medical therapies.10 In 1984, Potts et al reported endovascular deployment of a detachable balloon within a surgically created splenorenal shunt that resulted in complete shunt occlusion and substantially improved liver function.11 Use of coil embolization for surgical shunt occlusion was reported in 1987 via transfemoral and percutaneous transhepatic approaches,12 and a variety of techniques were subsequently implemented by surgeons and interventional radiologists for TIPS occlusion in the setting of refractory HE. These included various combinations of coil embolization and intra-TIPS Greenfield filter deployment.13,14 Also described was temporary transjugular inflation of latex occlusion balloons, left in place for up to 48 hours on a guidewire or with a supporting transjugular sheath to achieve shunt thrombosis without permanent indwelling foreign material, so as to allow subsequent recanalization.7,8 Table 18.1 West Haven Criteria for Grading of Hepatic Encephalopathy
Indications for Transjugular Intrahepatic Portosystemic Shunt Reduction
Table 18.1). The incidence of new or newly worsened hepatic encephalopathy (HE) after transjugular intrahepatic porto-systemic shunt (TIPS) creation has traditionally been reported as 20% to 31%, although some series have reported this figure to be as high as 44%, and a recent randomized multicenter study reported a rate of HE after TIPS of 33%.1–5 The rate of post-TIPS HE refractory to medical management has traditionally been established at 4% to 7%, although more recently this number has been reported to approach 8%.6–8 Despite initial concerns, rates of HE with covered TIPS appear to be the same or slightly less than as seen with bare-metal TIPS,9 although whether this reflects a difference in the design of TIPS shunt materials or a refinement of TIPS technique is uncertain. Although liver transplant is an option for a small subset of these patients, most will need endovascular TIPS revision. 
Table 18.2 outlines the indications and relative contraindications for TIPS reduction.
Reduction’s Predecessor: Transjugular Intrahepatic Portosystemic Shunt Occlusion
Grade | Clinical Signs |
I | Trivial lack of awareness Euphoria or anxiety Shortened attention span Impaired performance of addition |
II | Lethargy or apathy Minimal disorientation to time or place Subtle personality change Inappropriate behavior Impaired performance of subtraction |
III | Somnolence to semi-stupor but responsive to verbal stimuli Gross disorientation |
IV | Coma (unresponsive to verbal or noxious stimuli) |
Results
The proliferation of shunt occlusion procedures was limited by reports of rapidly ensuing hemodynamic instability, and death thought to be due to suddenly and severely reduced cardiac preload and renal perfusion as well as reports of recurrent variceal bleeding.12,13,15 A retrospective single-center analysis of 38 TIPS occlusion and reduction procedures performed over a 14-year period reported a high rate of TIPS occlusion-related complications, including a procedure-related death rate of 9% (3 of 29 TIPS occlusion patients). From these data, the authors strongly recommended newer reduction techniques over TIPS occlusion for refractory HE.14 Central embolization of the balloon or of the induced TIPS thrombus into the pulmonary circulation, either periprocedurally or during any subsequent recanalization attempt, has been an additional theoretical concern raised with all balloon-mediated TIPS occlusion techniques.13,16
Early Transjugular Intrahepatic Portosystemic Shunt Reduction Techniques: Reducing Stents
The first report of a technique for intentionally narrowing without occluding a TIPS was described in 1994 by Haskal and Middlebrook.17 This technique involved weaving a 3-0 silk suture circumferentially through the interstices of the midportion of a Wallstent (Boston Scientific, Natick, MA), which was partially deployed on a sterile back table, achieving a constrained stent diameter of 5 mm. The stent was then resheathed in a long 9-Fr sheath and deployed by unsheathing the stent from a transjugular approach coaxially within a long 12-Fr sheath. The authors acknowledged that the technique was more involved than many contemporary occlusion techniques but noted that the sutures could be broken with angioplasty if wider shunt patency is later desired. Reduced flow within the revised shunt was thought to be due to increased turbulence of flow because contrast was seen passing through the interstices of the newly placed constrained stent immediately after placement.
Various other techniques for deploying reducing stents within existing TIPS shunts were described. One of these made use of a coaxial smaller balloon-expanded stent to constrain a larger self-expanding stent.18 Another technique comprised partially deploying one end of a larger balloon-expanded stent and fully deploying the other.19 The narrow, partially deployed end of the stent reduced flow through the TIPS, and the wider fully deployed end fixed the new stent to the walls of the shunt.
Table 18.2 Indications and Contraindications for Transjugular Intrahepatic Portosystemic Shunt Reduction
Indications | Relative Contraindications* |
Refractory post-TIPS hepatic encephalopathy (strong indication) | Patient is candidate for liver transplant (can be bridge to transplant) |
Post-TIPS hepatic insufficiency (weak indication; transplant is preferred) | Patient cannot tolerate risk of rebleeding or recurrent ascites |
*There are no absolute contraindications.
TIPS: transjugular intrahepatic portosystemic shunt.
A premanufactured reducing stent was made commercially available in Europe in the mid-1990s. Preloaded in a 7-Fr delivery sheath, the self-expanding nitinol Memotherm stent (Angiomed, Karlsruhe, Germany) expanded to a predesigned hourglass shape. Postdeployment angioplasty with 10-, 12-, or 14-mm balloons would enlarge the ends of the stent for fixation, and smaller balloons could be used to open the midportion of the reducing stent to either 4 or 6 mm. A polyethylene terephthalate (PET, or Dacron polyester) fiber net was woven through the interstices of the narrow portion of the stent to induce thrombosis of the space between the original and reducing shunts.
Results
Similar to all literature reporting TIPS modification procedures, the literature describing use of reducing stents is composed of case reports and small single-center series. However, probably because they allowed both a partial and more gradual elevation in portosystemic gradient (PSG), reducing stents were much less often associated with fatal hemodynamic complications, and TIPS reduction quickly replaced TIPS occlusion in the 1990s.14 Haskal and Middlebrook17 reported their first stent immediately increased the patient’s PSG by 3 mm Hg, decreased shunt velocity by one third, and restored hepatopetal flow in portal branches as well as markedly reducing the patient’s HE. It remained patent through 8 months of follow-up. Results reported in small series describing other reducing stent techniques noted better success in treating patients with HE than those with more fulminant hepatic insufficiency.20,21 It was hypothesized that either the procedure itself or the maximum hemodynamic effect of shunt reduction took place too long after hepatic insufficiency ensued to reverse the cascade of hepatic necrosis. In contrast to their TIPS occlusion predecessors, there were no procedure-related complications described with these TIPS reduction techniques.
When stent-based TIPS reduction techniques were found inadequately to decrease flow, embolization of spaces between the reducing stents and original TIPS was advocated, either with an emulsion of iodized oil and hydroxylated corn protein derivative (Ethibloc; Ethicon, Norderstedt, Germany) or with coils.19,22
The investigators who initially described use of the Memotherm prefabricated reducing stent reported clinical response in 4 of 7 patients.20 Subsequently, however, other researchers found clinical improvement in only 2 of 6 patients treated with the Memotherm stent. It is no longer commercially available.21
Modern Techniques: Reducing Stent Grafts
Several covered stents have become commercially available in the past decade, allowing development of a multitude of new TIPS reduction techniques. Roughly, these techniques can be categorized into five categories, as follow.
Balloon-Expanded Stent Graft Sculpting Techniques
Quaretti et al first described use of a covered stent in TIPS reduction, making use of an extended polytetrafluoroethylene (ePTFE)–covered balloon-expanded stainless steel stent (Jostent; Jomed, Rangendingen, Germany).23 The procedure requires deploying the stent graft on a sterile back table. A 48-mm-long Jostent, balloon-expandable from 6 to 12 mm in diameter is tightly crimped onto a 12 × 40-mm balloon catheter (Opta; Cordis, Roden, The Netherlands), such that the balloon lies half within and half outside what will be the inferior third of the reducing stent graft (with the stent crimped only to the superior half of the balloon). The stent graft is then deployed through a 10-Fr-long sheath placed within the original TIPS by inflating the balloon where loaded in the inferior third of the stent graft, deflating the balloon, repositioning it halfway within the superior third of the stent graft and reinflating, leaving the middle third of the covered stent at its factory minimum 6-mm diameter. Gastroesophageal varices were embolized with coils and 3% Polidocanol detergent sclerosant before reducing the shunt.
Another technique using covered Jostents for TIPS reduction was described by Fanelli et al using a 3-0 polyglactin suture tied around the midportion of a 10 × 40-mm balloon catheter (Wanda, Boston Scientific).24 The covered Jostent is then deployed on a back table, hand mounted on the balloon catheter, and advanced into the midportion of the TIPS via a 10-Fr jugular sheath. The balloon is insufflated to nominal pressure, deflated, and removed. A 5-mm balloon is then insufflated in the midportion of the newly deployed reducing stent graft. Larger balloons can be used as needed to achieve the desired hemodynamic response. 
Fig. 18.1 illustrates this constraining suture concept.
Kroma et al25 described direct deployment of iCast stent grafts to reduce TIPS using either 10 × 38-mm or 10 × 59-mm devices. Intentionally incomplete insufflation of the factory-installed deployment balloon is used to create a centrally narrowed configuration of the iCast stent graft, conceptually outlined in 
Fig. 18.2. Serially larger angioplasty balloons were used in the midportion of the deployed iCast to decrease as needed the amount of shunt flow reduction. The authors emphasize that other ePTFE-covered balloon-expanded stents may not expand with the same symmetry.
Results
Quaretti et al23 found both technical and clinical success intervening in a patient developing liver failure 1 week after TIPS. The PSG increased from 10 to 25 cm H2O. Peak velocity in the reduced shunt increased from 130 to 195 cm/s, and flow in the shunt, as measured by Doppler, decreased from 2.6 to 1.8 L/min. Serum bilirubin fell from 23 to 3.5 mg/dL 7 days after reduction and 1.5 mg/dL at 7-month follow-up. There were no procedure-related complications, and the patient remained free of recurrent bleeding through the follow-up period.
Fanelli et al24 claimed technical, hemodynamic, and clinical success in all 12 patients described in their case series. They reported no difficulties with deployment and found a mean increase in PSG from 6.6 to 15.1 mm Hg. Doppler examinations performed 1 day after reduction revealed an average decrease in velocity of shunt flow from 85 to 25 cm/s. To raise the PSG to desired levels, use of 5-mm balloons to angioplasty the center of the shunt was required in 2 of 12 cases, but most patients (9 of 12) required 6-mm angioplasty, and one required balloon expansion to 7 mm. Mean serum ammonia levels decreased from 168 to 73 mcg per 100 mL. Although not directly reported, mean pre- and post-TIPS reduction West Haven HE grade calculated from the data presented in their report declined from 2.9 to 0.4. Similarly calculated mean serum bilirubin level was 1.9 mg/dL before and 1.6 mg/dL after TIPS reduction. Mean model for end-stage liver disease (MELD) scores were 13 before and 12 after reduction. No analysis was performed of correlation between these values and survival or between other variables on which data were collected and outcomes, including Child-Pugh class, age, or indication for the original TIPS, although the raw data themselves were presented. The authors reported that at 1-year follow-up, 6 patients were alive and well, 4 had died of cardiac or multiorgan failure (2 during the first 30 days after reduction), 1 received a liver transplant and did well, and 2 were lost to follow-up. Although they did not report prereduction embolization of gastroesophageal varices, the group also did not report rebleeding during follow-up.
Fig. 18.2 Incomplete iCast insufflation. An iCast polytetrafluoroethylene (PTFE)-covered balloon-expandable stainless steel stent graft is incompletely insufflated on its factory-mounted balloon catheter. Unlike as depicted in Fig. 18.1, there is no constraining suture or other constraining device used with this technique. The balloon catheter is removed, leaving the covered stent graft in place. This technique has been limited in vivo by cephalad migration of the reducing stent graft during withdrawal of its deployment balloon.
Kroma et al25 reported technical difficulty in deploying each of the 4 iCast PTFE-covered reducing stents in the series describing their technique of partial factory-mounted i-Cast balloon insufflation to achieve a narrow, reducing waist. Each reducing stent graft was inadvertently partially withdrawn on removal of its deploying balloon, the authors suspected, because of friction of the balloon on the narrow, incompletely deployed portion of the reducing stent graft and lack of sufficient friction between the more completely deployed ends of the reducing stent graft. In 3 of 4 cases, the ends of the iCast were more completely apposed to the walls of the original TIPS using a separate 6-mm-diameter balloon. In one case, despite this additional maneuver, the iCast stent graft moved cephalad on withdrawal of the access sheath, so a bare-metal 10 × 26-mm balloon-expanded stent (Lifestent; Edwards Lifesciences, Irvine, CA) was deployed, overlapping the cephalad edge of the iCast as an anchor. The authors measured final PSG but used angiographic demonstration of return of minimal antegrade portal branch flow as their determinant of sufficiency of TIPS flow reduction. Coil embolization of recurrent flow within large gastric varices was performed as needed in one case. A mean increase of PSG of 8 mm Hg (59%) was noted. Serum ammonia levels changed from a mean of 60 to a mean of 51 in the three subjects for whom it was calculated. Bilirubin changed from 26 to 18. Mean MELD scores were 24 both before and after the reducing procedures. HE grades were 1.8 before and 2.2 after the reduction procedures in this small series. Mean survival time after TIPS reduction was 148 days when including 1 patient who received a transplant and 68 days excluding that patient. None of the deaths was found to be procedure related.
Purse-String Suture–Mediated Reduction Technique
Madoff et al26 described the first TIPS reduction to make use of a Wallgraft (Boston Scientific, Natick, MA), a PET-covered Wallstent. In their permutation of the reducing stent technique, either a 10- or 12-mm-diameter Wallgraft is fully deployed on a sterile back table. A 6- or 8-mm angioplasty balloon or corresponding dilator is used to appropriately size the narrow portion of the stent graft, which is then constrained with a purse-string 3-0 silk suture woven between the graft’s interstices approximately one-third the distance from its leading end. A scalpel may be used to cut the covering from the trailing half of the Wallgraft so as to prevent inadvertent occlusion of the hepatic vein. The modified Wallgraft is then loaded into the tip of a long 9- or 10-Fr sheath and deployed within the TIPS shunt by unsheathing the reducing stent graft while pinning it in place using the sheath’s dilator with its tip cut off to serve as a pusher. Variations of the technique were subsequently described by several groups, one of which described coil embolization of a large esophageal varix before shunt reduction.27,28 An illustration of a reducing stent graft deployed using this type of technique is illustrated in 
Fig. 18.3. An example of such a reducing stent graft seen in vivo is shown in 
Fig. 18.4.
