Transjugular Intrahepatic Portosystemic Shunt (TIPS)
Portal hypertension is a relatively rare disorder in childhood compared to adults, where the majority of cases are caused by alcohol abuse (in western parts of the world), and viral hepatitis and cirrhosis (in Africa and Asia). In children the cause of portal hypertension lies in extra-hepatic biliary atresia, portal vein thrombosis, hepatitis and toxic liver injury (Cwikiel 2002; Cwikiel et al. 2003; Huppert et al. 1998). Clinical manifestations of portal hypertension consist of ascites production and the development of oesophageal varices. Oesophageal varices have a tendency to bleed and this can cause a life-threatening situation. The first line of treatment is repeated paracentesis for the reduction of ascites and endoscopic sclerotherapy or rubber banding for oesophageal variceal haemorrhage. In case of repeated haemorrhage from oesophageal varices, shunting of blood away from the portal system thereby reducing the pressure in the collateral vessels, is necessary. Initially porto-systemic shunts consisted of surgical spleno-renal, porto-caval or meso-caval shunts. These surgical procedures however, carry a high morbidity and mortality rate. As far back as 1969, Rösch et al. suggested creating an intrahepatic shunt. However, it was not until the development of endovascular stents that this gained momentum (Rösch et al. 1969). In 1994, The United States National Digestive Diseases Advisory Board established the following clinical indications for Tips: first, acute variceal bleeding that cannot be successfully controlled with medical treatment, including sclerotherapy. Second, recurrent and refractory variceal bleeding or recurrent variceal bleeding in patients who cannot tolerate conventional medical treatment, including sclerotherapy and pharmacologic therapy (Shiffman et al. 1995). There are also some indications for which there is no scientific proof of the effectiveness of TIPS. These consist of medically refractory ascites, refractory hepatic hydrothorax, Budd-Chiari syndrome, veno-occlusive disease, hepatorenal syndrome and hypersplenism (Heyman et al. 1997). To date there is no indication that TIPS is useful in preventing variceal haemorrhage in patients who are awaiting liver transplantation. Its use for initial prevention of variceal haemorrhage is also discouraged.
There are several contraindications for TIPS: absolute contraindications consist of right-sided heart failure with elevated central venous pressure, polycystic liver disease, and severe hepatic failure (Shiffman et al. 1995). The latter contraindication is based on the fact that the TIPS shunts blood away from the liver, thus further compromising liver function. Relative contraindications consist of active or systemic infection, as TIPS makes use of a foreign device that could act as a colonization site for bacteria, severe hepatic encephalopathy poorly controlled by medical therapy and portal vein thrombosis.
Due to the nature of the procedure TIPS will always be performed under general anaesthesia. The right jugular vein is punctured and a sheath is inserted. A catheter and a guidewire are advanced into the inferior caval vein and from there into preferably the middle or else the left hepatic vein. A special TIPS stainless steel angled catheter is exchanged over the guidewire and positioned in the middle or left hepatic vein. Under ultrasonic guidance or a wedged venogram an intrahepatic portal vein is punctured transhepatically using a special needle. Performing TIPS requires a thorough knowledge of the venous hepatic anatomy and its variations. After confirmation of intrahepatic portal venous position by use of contrast medium, a needle catheter is passed into the portal vein. When intrahepatic portal vein location is proven, the parenchymal tract is dilated and lined with a stent (Fig. 7.12). A TIPS is considered to be successful if the pressure gradient is less than 15 mm Hg. Care should be taken in placing the stent. It should not protrude into the inferior caval vein, since most children will at some point in time require a liver transplant. A stent placed into the inferior caval vein can complicate transplantation surgery.
TIPS has been shown to be a safe and effective treatment for portal hypertension and compared to endoscopic sclerotherapy it has proven to be a more effective and safer technique (Garcia-VillarreaL et al. 1999). In primary cases endoscopic band liga-tion has shown to be as effective as TIPS in a randomized control study (Pomier-Layrargues et al. 2001). In a long term follow up study in adult TIPS patients, rates of rebleed from oesophageal vari-
Fig. 7.12. a A 9.6-year-old boy with a split liver transplantation (segments II and III). The patient was admitted to the paediatric intensive care because of severe haematemesis. The fluoroscopy image shows the TIPS catheter (arrow) placed within the portal vein. Multiple collateral vessels are shown (curved arrow). b After dilation of the puncture tract, two self-expandable stents (Smart diameter 9 mm., Cordis, Johnson & Johnson Medical N.V., Belgium) were placed. Angiography shows that the collaterals have collapsed and that the primary flow direction is through the TIPS. c Measurements of intravascular pressures shows the gradient to be 8 mm Hg, well below the threshold level of 15 mm Hg ces after 1, 2 and 5 years were 21%, 21% and 27%, respectively (ter Borg et al. 2004).
A major concern of TIPS has been the development of encephalopathy. In a studyby Pomier-Layrargues et al. (2001), 47% of the TIPS patients developed encephalopathy versus 44% in the endoscopic band ligation population; however, this difference was not significant. Of note is that encephalopathy does occur less frequent in children than in adults, although there is no clear reason for this observed difference in risk (Heyman and LaBerge 1999).
As with all interventional procedures, TIPS has its complications. The main complication is procedure-related mortality, which has been reported to be 2% (Freedman et al. 1993). The 30-day mortality of emergency surgical shunts ranges from 40%-100% compared to 7%-45% for TIPS (Heyman et al. 1997). In TIPS the majority of cases of mortality and morbidity are related to severity of disease, with death occurring in those with the worst Child-Pugh classification. Complications related to the TIPS itself are shunt occlusion and stenosis. Intimal hyperplasia is the most common cause of stenosis and subsequent occlusion, although the use of covered stents should largely overcome this problem. In case of stenosis, restenting or balloon dilatation will, for the majority, successfully solve the problem (Heyman et al. 1997).
Fig. 7.13. A 1-year-old boy with a solid tumour arising from the adrenal gland. Biopsy was performed to confirm the diagnosis of neuroblastoma and to obtain specimen for genetic marker studies. The biopsy was done using freehand technique, the arrow delineates the biopsy needle. S, spleen; M, mass
In adults the initial technical success rate of TIPS is reported to be over 95%. A Dutch study on long term outcome of TIPS in adult patients showed that the risk of definitive loss of shunt function was 17% at 5 years follow up (ter Borg et al. 2004). HeymaN et al. (1999) presented literature data on 40 paedi-atric TIPS procedures. In this overview, six (6.6%) complications were found, and although patency was not assessed, the longest follow-up was over 800 days.
Was this article helpful?
Do You Suffer From High Blood Pressure? Do You Feel Like This Silent Killer Might Be Stalking You? Have you been diagnosed or pre-hypertension and hypertension? Then JOIN THE CROWD Nearly 1 in 3 adults in the United States suffer from High Blood Pressure and only 1 in 3 adults are actually aware that they have it.