Transjugular intrahepatic portosystemic shunt reduction for refractory hepatic encephalitis

Clinical History

A 63-year-old female patient presented with refractory hepatic encephalopathy due to progressive hepatitis C cirrhosis 23 months after Transjugular Intrahepatic Portosystemic Shunt (TIPS) placement. The initial TIPS had been performed for massive variceal bleeding with reduction of the portosystemic gradient from 22 mmHg to 8 mmHg.

Imaging Findings

A decision for TIPS revision was made. Initial angiography demonstrated a patent 10 x 90 mm VIATORR stent (Gore, Flagstaff, Arizona) cranially extended to the IVC with a 10 x 40 mm FLUENCY (Bard, Tempe, Arizona) stent. On contrast injection, limited filling of the main portal branches and absence of varices (Fig. 1) was seen, corresponding to the measured 8 mmHg gradient. To reduce the lumen of the TIPS stent, a 10 x 39 mm iCAST (Atrium, Hudson, New Hampshire) stent was inserted into the VIATORR stent, but the delivery balloon was only partially (4 mm) inflated. This resulted in a flow-restricting hourglass configuration (Fig. 2). The diameter was gradually increased from 4 to 6 mm, resulting in a final gradient of 14 mmHg. Post-reduction imaging reflects the increased TIPS resistance with contrast filling of segmental intrahepatic portal vein branches and visualisation of some gastric varices (Fig. 3).

Discussion

A. Background
Hepatic encephalopathy results from diversion of portal blood from the liver which prevents nitrogenous compounds from being metabolized. The neurotropic factors leading to hepatic encephalopathy include cytokines, oxidative stress, and altered levels of serotonin, ammonia, histamine, and GABA [1]. After creation of a TIPS, hepatic encephalopathy can occur in 17 to 46 per cent of patients [2]. The majority of patients can be controlled medically with only 3 to 7 per cent being refractory to medical treatment [3]. Medical treatment includes the disaccharide Lactulose and the antibiotic Rifaximin. Both approaches aim to reduce the amount of intestinal bacteria producing neurotoxins [1].
B. Clinical Perspective
Refractory hepatic encephalopathy poses a treatment dilemma between increasing the portosystemic shunt resistance to increase liver perfusion and blood “detoxification” while keeping the gradient low enough to prevent the recurrence of variceal haemorrhage. A gradient greater than 8 mm Hg typically has a low likelihood of the patient developing encephalopathy [4].
C. Imaging Perspective
Routine surveillance for TIPS dysfunction consists of Doppler Ultrasound evaluation every six months with acceptable flow velocities ranging from 90 to 200 cm/s [5]. Significant changes should prompt an angiographic evaluation. Since hepatic encephalopathy is a clinical diagnosis, it is important to follow patients in a dedicated clinical setting.
The balloon-mounted iCAST stent is anchored by the initial opening of both ends, followed by a gradual opening of the mid-part which allows precise lumen control. Occasionally, subsequent addition of an oversized, self-expanding stent inside of the iCast is needed to assure its stability inside of the TIPS-stent.
Other methods to reduce a TIPS include [2]: Insertion of two adjacent stents and stent grafts - allowing up- and down regulation of the shunt, suturing the midsection of a stent prior to delivery - bearing the risk of a predetermined diameter and possible suture failure, and complete coil occlusion of the shunt as the most extreme form.
D. Outcome
In small studies, the majority of patients undergoing TIPS reduction for hepatic encephalopathy can experience a decrease in symptoms within 72 hours [6]. Our patient demonstrated significant clinical improvement without a recurrent episode of bleeding varices. However, the overall prognosis remains severely limited due to the underlying impaired liver function with liver transplant as the only curative option.
E. Take Home Message, Teaching Points:
For intractable hepatic encephalopathy after TIPS placement, a reduction may be indicated to improve the quality of life, while avoiding recurrent episodes of variceal bleeding.

Differential Diagnosis List

Final Diagnosis

Refractory hepatic encephalopathy successfully treated with TIPS reduction.

URL:	https://www.eurorad.org/case/11452
DOI:	10.1594/EURORAD/CASE.11452
ISSN:	1563-4086