The Danis stent for oesophageal variceal bleeding

The main clinical evidence comprises 9 studies

3.1 The evidence assessed by the external assessment centre (EAC) included 9 full text peer-reviewed studies including 247 people. Two of the studies were comparative, a randomised controlled trial (RCT) and a retrospective case-controlled study. The remaining 7 studies were non-comparative case series. For full details of the clinical evidence, see section 3 of the assessment report.

The comparative evidence is relevant to the decision problem but has limitations

3.2 Both comparative studies compare the use of the Danis stent with balloon tamponade. The studies report that using the Danis stent improves control of bleeding at 5 and 15 days. The RCT (Escrosell et al. 2016) is the strongest evidence for the Danis stent and reports a composite end point including control of bleeding and adverse events but it is underpowered for this result. The retrospective case-controlled study only included patients with acute-on-chronic liver failure and there were significant differences between disease severity scores of the patients in the control group compared with the interventional group. The EAC reported that both studies have a moderate risk of bias.

The RCT (Escorsell et al. 2016) is not reflective of the UK care pathway

3.3 The RCT was done in Spain and differences in the care pathway limit the generalisability of the findings to the UK setting. Expert advisers stated that the definitive procedure, transjugular intrahepatic portosystemic shunt (TIPS), was delivered at an earlier stage after presentation in this trial than it would be in the UK.

The EAC did a meta-analysis on the 7 non-comparative studies

3.4 The 7 non-comparative studies are low in quality. The studies have broadly similar populations and outcomes. Outcomes with low heterogeneity were included in the analysis. Immediate bleeding control was found to have been achieved in 88% of cases (95% CI: 0.38 to 0.9) based on the 7 case series, one of which (Wright et al. 2010) was done in the UK. Survival rate at 30 days was 68% from 3 studies.

The company used a cost-calculator model to compare the cost of using the Danis stent with balloon tamponade

3.5 The cost comparison has a 6-week time horizon and is from an NHS and personal and social services perspective. The model estimates the cost associated with the use of the Danis stent compared with balloon tamponade as bridging treatment for patients aged 16 or over with acute refractory oesophageal variceal bleeding in whom first-line therapy is unsuitable or has failed. The model captures the cost of the initial procedures, the likelihood of adverse events for both technologies and the cost and use of resources to remove the devices. The key model parameters are:

For full details of the cost evidence, see section 4 of the assessment report.

The EAC updated 5 cost parameters

3.6 Updated cost parameters include:

The EAC's updates to the cost model change the direction of the cost case

3.7 With the updated cost parameters, the EAC's base case shows that the Danis stent is cost incurring by £923 per person. The company also presented 3 scenario analyses, all of which the EAC considered relevant. Scenario 1 modelled the cost of using each technology by cumulating the costs of the resources needed. Scenarios 2 and 3 explored uncertainty in the assumed impact of the bridge treatment on the choice of definitive treatment including (scenario 3) and excluding (scenario 2) hepatic encephalopathy costs.

Two additional scenario analyses were done to include a second endoscopy for patients that have a balloon tamponade

3.8 Clinical experts highlighted that a second endoscopy at the time of balloon removal is needed for people that have balloon tamponade and that the choice of definitive treatment is done on a case by case basis regardless of the bridging treatment used. Therefore scenarios 4 and 5 were done to include the cost of a second endoscopy:

Resource parameters in the micro costed model were updated based on expert advice and data about hospital admissions

3.9 Estimates about resource use in the care pathway were updated based on expert advice and were reported as scenarios 5A and 5B. The key parameters that were changed are: