Key messages
– Expanded polytetrafluoroethylene (ePTFE)-covered stents may be more likely to reduce mortality (deaths), upper gastrointestinal bleeding, recurrence of ascites (a condition where fluid collects in spaces within your abdomen), and shunt dysfunction compared with bare stents of the same diameter.
– Beneficial effects of ePTFE-covered stents remain unclear when comparing with bare stents of different diameters.
Technical terms: ePTFE
ePTFE is a variation of polytetrafluoroethylene (PTFE) that has been modified to have a porous structure. The material is created by stretching PTFE, which forms a network of interconnected nodes and fibrils (fibres). This porous structure allows the passage of fluids and gases through the material while retaining the desirable properties of PTFE, such as its chemical resistance.
What is liver cirrhosis?
Liver cirrhosis is a condition where healthy liver tissue is gradually replaced by scar tissue. This scarring can affect the liver's ability to function properly and can be caused by various factors such as chronic alcohol abuse, viral infections, or other diseases.
What is portal hypertension?
People with liver cirrhosis often develop a complication called portal hypertension, which is high blood pressure in the blood vessels that supply the liver. This can lead to serious complications such as internal bleeding, fluid accumulation, and enlargement of the veins in the oesophagus (food pipe) and stomach.
How is portal hypertension treated?
To treat portal hypertension, a procedure called transjugular intrahepatic portosystemic shunt (TIPS) is often performed. During TIPS, a stent (a short tube) is inserted to create a pathway between the portal vein and hepatic vein, redirecting the blood flow and reducing pressure. Unfortunately, the conventional bare stents used in the TIPS procedure are sometimes blocked within one year. Researchers have found that a new type of stent, covered with ePTFE, may help prevent this blockage.
What did we want to find out?
We wanted to find out if the ePTFE-covered stents were better than bare stents in TIPS in people with liver cirrhosis to improve mortality, procedure-related complications, and quality of life.
What did we do?
We searched for studies that looked at ePTFE-covered stents compared with bare stents for TIPS in people with liver cirrhosis. We compared and summarised the results of the studies and rated our confidence in the evidence, based on factors such as study methods and sizes.
What did we find?
We found four studies that involved 565 people with liver cirrhosis. We found that using ePTFE-covered stents yielded better results in terms of death from all causes (all-cause mortality), upper gastrointestinal bleeding, recurrence of ascites, and shunt dysfunction when using the same diameter as bare stents. There were no difference in the occurrence of hepatic encephalopathy (a condition that affects mental and neurological function) in the two groups. However, there were no differences between ePTFE-covered stents and bare stents of different diameters on number of deaths, procedure-related complications, upper gastrointestinal bleeding, hepatic encephalopathy, kidney failure, or shunt dysfunction. There was a reduced number of people with recurrence of ascites in the ePTFE-covered group compared to the bare stents of different diameters.
What are the limitations of the evidence?
We have very little or no confidence in the evidence mainly because studies were very small and people in the studies might have been aware of which treatment they were getting.
Funding
One study did not clearly report funding sources. The remaining three studies declared that they had no funding with vested interests.
How up to date is this evidence?
The evidence is up to date to February 2023.
Based on the small number of trials with insufficient sample size and events, and study limitations, we assessed the overall certainty of evidence in the predefined outcomes as low or very low. Therefore, we are uncertain which of the two interventions (ePTFE-covered stents or bare stents of the same diameter and ePTFE-covered stents versus bare stents of different stent diameters) is effective for the evaluated outcomes. None of the four trials reported data on health-related quality of life, and data on complications were either missing or rarely reported.
We lack high-quality trials to evaluate the role of ePTFE-covered stents for TIPS for managing people with liver cirrhosis.
Transjugular intrahepatic portosystemic shunt (TIPS) is a widely used procedure for management of uncontrolled upper gastrointestinal bleeding and refractory ascites in people with liver cirrhosis. However, nearly half of the people experience shunt dysfunction and recurrent symptoms within one year of the procedure. Expanded polytetrafluoroethylene (ePTFE)-covered stents are assumed to decrease shunt dysfunction by approximately 20% to 30%.
To evaluate the benefits and harms associated with the use of expanded polytetrafluoroethylene (ePTFE)-covered stents versus bare stents in transjugular intrahepatic portosystemic shunts (TIPSs) for managing people with liver cirrhosis.
We used standard, extensive Cochrane search methods. The latest search date was 28 February 2023.
Randomised clinical trials comparing ePTFE-covered stents versus bare stents in TIPS for treatment of people with liver cirrhosis.
We used standard Cochrane methods. Our primary outcomes were 1. all-cause mortality, 2. procedure-related complications, and 3. health-related quality of life. Our secondary outcomes were 4. upper gastrointestinal bleeding, 5. recurrence of ascites, 6. hepatic encephalopathy, 7. kidney failure, 8. early thrombosis, 9. non-serious adverse events, and 10. shunt dysfunction. We used GRADE to assess certainty of evidence.
We analysed outcome data at the maximum follow-up, except for the 'early thrombosis' outcome for which it was within 12 weeks after the TIPS procedure.
We included four trials with 565 randomised participants (age range: 18 to 75 years; male range: 63.6% to 75.0%). A total of 527 participants provided data for analyses because of losses to follow-up. Two trials were conducted in China; one in France; and one in France, Spain, and Canada. Participants were classified with cirrhosis Child-Pugh class A, B, or C, and for some, the class was not reported. We used intention-to-treat principle (four trials) and per-protocol analysis (one trial) to meta-analyse the data.
One trial compared ePTFE-covered stents versus bare stents of the same diameter and three trials compared ePTFE-covered stents versus stents of different diameters.
ePTFE-covered stents versus bare stents of the same diameter
One trial with 258 participants compared 8 mm covered stent versus 8 mm bare stent.
Mortality in the covered stent group is possibly lower than in the bare stent group (risk ratio (RR) 0.63, 95% confidence interval (CI) 0.43 to 0.92; low-certainty evidence). Upper gastrointestinal bleeding (RR 0.54, 95% CI 0.35 to 0.84), recurrence of ascites (RR 0.42, 95% CI 0.20 to 0.87), and shunt dysfunction (RR 0.42, 95% CI 0.28 to 0.61) occurred more often in the bare stent group than in the covered stent group (all low-certainty evidence). There was no difference in hepatic encephalopathy between groups (RR 1.10, 95% CI 0.76 to 1.61; very low-certainty evidence). The trial did not report data on procedure-related complications, health-related quality of life, early thrombosis, and segmental liver ischaemia (a non-serious adverse event).
ePTFE-covered stents versus bare stents of different stent diameters
Three trials compared ePTFE-covered stents versus bare stents of different diameters (10.5 (standard deviation (SD) 0.9) mm versus 11.7 (SD 0.8) mm; 8 mm versus 10 mm; and one trial used 10-mm stents that could be dilated from 8 mm to 10 mm).
There was no evidence of a difference between the ePTFE-covered stents versus bare stents groups in mortality (RR 0.75, 95% CI 0.48 to 1.16; 3 trials, 269 participants), procedure-related complications (RR 0.53, 95% CI 0.05 to 5.57; 1 trial, 80 participants), upper gastrointestinal bleeding (RR 0.46, 95% CI 0.15 to 1.38; 3 trials, 269 participants), hepatic encephalopathy (RR 0.93, 95% CI 0.66 to 1.30; 3 trials, 269 participants), and kidney failure (RR 7.59, 95% CI 0.40 to 143.92; 1 trial, 121 participants) (all very low-certainty evidence). Recurrence of ascites (RR 0.30, 95% CI 0.11 to 0.85; 3 trials, 269 participants; low-certainty evidence), shunt dysfunction (RR 0.50, 95% CI 0.28 to 0.92; 3 trials, 269 participants; low-certainty evidence), and early thrombosis (RR 0.28, 95% CI 0.09 to 0.82; I2 = 0%; 3 trials, 261 participants; very low-certainty evidence) occurred more often in the bare stents group. There was no evidence of a difference in segmental liver ischaemia (RR 5.25, 95% CI 0.26 to 106.01; 1 trial, 80 participants; very low-certainty evidence). No trial presented data on health-related quality of life.
Funding
One trial did not clearly report funding sources. The remaining three trials declared that they had no funding with vested interests.