Key points from the evidence
Scottish Health Technologies Group (SHTG)
- Evidence was available on two types of endobronchial valve: the Zephyr® Endobronchial Valve System (Pulmonx International) and the Spiration® Valve System (Olympus Inc.).
- Three meta-analyses, based on the same seven randomised controlled trials (RCTs), compared the Zephyr® valve plus medical therapy with medical therapy alone or a sham procedure plus medical therapy. The results from the meta-analyses are summarised in table A. The findings for all clinical effectiveness outcomes favoured the intervention group. The Zephyr® valve was associated with a significantly increased risk of serious adverse events or a pneumothorax
Table A: effectiveness and safety of the Zephyr® valve plus medical therapy compared with medical therapy alone or a sham control plus medical therapy in patients with severe or very severe heterogeneous or homogenous emphysema and little or no collateral ventilation
| Outcome | n studies (n patients) | Findings (95% CI) | p-value | GRADE assessment |
| Clinical effectiveness outcomes | ||||
| FEV1 % predicted | 7 (879) | WMD 18.8% (14.2% to 23.5%) | <0.00001 | High |
| SGRQ score | 7 (871) | WMD -7.0 points (-9.9 points to -4.4 points) | <0.00001 | High |
| 6MWT | 7 (876) | WMD 39.9m (18.4m to 61.3m) | 0.0003 | Moderate |
| Residual lung volume | 5 (470) | MD -0.5L (-0.8L to -0.3L) | <0.00001 | - |
| Safety outcomes | ||||
| Serious Adverse Events (prolonged hospitalisation, life-threatening events, mortality) | 6 (819) | RR 3.1 (1.5 to 6.6) | 0.003 | High |
| Pneumothorax | 5 (793) | RR 6.3 (3.7 to 10.7) | 0.0001 | High |
| Mortality | 7 (990) | RR 1.1 (0.6 to 2.4) | 0.72 | Moderate |
| COPD exacerbation | 9 (990) | RR 0.99 (0.8 to 1.99) | 0.93 | Moderate |
FEV1 = forced expiratory volume in 1 second, SGRQ = St George’s respiratory questionnaire (lower scores indicate higher quality of life), 6MWT = 6 minute walk test, COPD = chronic obstructive pulmonary disease, CI = confidence interval, WMD = weighted mean difference, MD = mean difference, RR = relative risk, L = litres, m = metres, GRADE = Grading of Recommendations Assessment, Development and Evaluation
- A meta-analysis of four RCTs compared the Spiration® valve plus medical therapy with medical therapy alone or a sham procedure plus medical therapy in patients with severe or very severe emphysema. A sub-group analysis assessed the effects of the Spiration® valve in patients with little or no collateral ventilation. Results from the meta-analyses are summarised in table B. All statistically significant results (effectiveness and safety) favoured the intervention group.
Table B: effectiveness and safety of the Spiration® valve plus medical therapy compared with medical therapy alone or a sham control plus medical therapy in patients with severe or very severe heterogeneous emphysema
| Outcome | All patients (4 studies; n=629) | No collateral ventilation (2 studies; n=179) | GRADE assessment |
| Findings (95% CI) | |||
| Clinical effectiveness outcomes | |||
| FEV1 % predicted | MD 2.0% (-2.5% to 6.6%) NS | MD 4.2% (2.9% to 5.4%) p<0.05 | Low |
| SGRQ score | MD -6.5 points (-16.1 points to 3.0 points) p=0.18 | MD -12.3 points (-15.8 points to -8.7 points) p<0.00001 | Low |
| 6MWT | MD 4.6m (-21.9m to 31.0m) p=0.74 | MD 19.0m (-9.4m to 47.5m) p=0.19 | Very low |
| Residual lung volume | MD -0.01L (-0.5L to 0.5L) p=0.98 | MD -0.4L (-0.6L to -0.2L) p=0.0005 | Low |
| mMRC dyspnoea score | MD -0.3 points (-0.6 points to -0.05 points) p=0.02 | MD -0.5 points (-0.7 points to -0.3 points) p<0.00001 | Low |
| Safety outcomes | |||
| Pneumothorax | RR 1.9 (0.4 to 8.7) p=0.41 | RR 4.6 (0.8 to 26.2) p=0.08 | Low |
FEV1 = forced expiratory volume in 1 second, SGRQ = St George’s respiratory questionnaire (lower scores indicate higher quality of life), 6MWT = 6 minute walk test, mMRC = modified Medical Research Council, CI = confidence interval, MD = mean difference, RR = relative risk, NS = non-significant, L = litres, m = metres, GRADE = Grading of Recommendations Assessment, Development and Evaluation
- A network meta-analysis comparing the Zephyr® and Spiration® valves in patients with severe or very severe heterogeneous emphysema and no collateral ventilation, found no statistically significant differences between the valves for any outcome.
- Two qualitative studies found that patients had a strong desire to take action to improve their quality of life and breathlessness, despite procedure-associated risks, and valued both surgical and endobronchial valve procedures for lung volume reduction. A quantitative analysis (n=294) found that, on average, respondents preferred interventions (surgical or endobronchial) over current treatment, and favoured endobronchial valves over surgery.
- The results of a cost-utility analysis from the German healthcare system perspective indicated that over a 5- and 10-year time horizon, the Zephyr® valve was associated with increased quality-adjusted-life-years (QALYs) and higher costs compared with medical therapy alone. The incremental cost effectiveness ratio (ICER) at five years was €46,322 (£41,401) and at 10 years was €25,142 (£22,471). The analysis had a number of limitations affecting the generalisability of results, including selection of patients who had a positive outcome from valve implantation, comparison only with medical therapy rather than other procedures, and costs data from a non-UK healthcare setting.
- No cost effectiveness evidence was identified for the Spiration® valve.