Endobronchial valve insertion to reduce lung volume in emphysema

A systematic review (SR) and meta-analysis included 5 randomised controlled trials (RCTs) of patients (n=703) treated by duckbill-shaped endobronchial valve (EBV) insertion and 3 RCTs of patients (n=372) treated by umbrella-shaped EBV insertion, both compared with standard medical care (SMC). These 2 groups were analysed separately. In a meta-analysis of the 5 RCTs of duckbill EBV insertion compared with SMC, there was a statistically significant difference in 1% change from baseline in forced expiratory volume in 1 second (FEV₁) in favour of duckbill EBV insertion (standardised mean difference [SMD] 0.48, 95% confidence interval [CI] 0.32 to 0.64, p<0.00001, I²=42). In 2 RCTs (n=143) from the same meta-analysis, a 2% increase in FEV₁ was statistically significantly more frequent in patients treated by duckbill EBV than in those treated by SMC at 90‑day follow-up (SMD 0.77, 95% CI 0.43 to 1.11, p<0.00001, I² = 0%). In the other 3 RCTs (n=560) from the same meta-analysis, a 2% increase in FEV₁ was statistically significantly more frequent in patients treated by duckbill EBV than in those treated by SMC at 6‑month follow-up (SMD 0.40, 95% CI 0.22 to 0.58, p<0.00001, I²=41%). One RCT (n=73), which studied patients treated by the umbrella EBV, reported no statistically significant difference in FEV₁ measurements at 3‑month follow-up (MD 0.90 litres, standard deviation [SD] 0.34) compared with patients having SMC (0.87 litres, SD 0.34, p=0.065). A second RCT (n=22) of the umbrella EBV reported statistically significantly improved FEV₁ measurements in patients treated unilaterally (21.4%, SD 10.7%) but not in patients treated bilaterally (−3.1%, SD 15.0; MD 24.50%, 95% CI 13.61 to 35.39). The SR reported a statistically significantly larger change in FEV₁ from baseline in patients with heterogeneous emphysema treated by duckbill EBV than in patients with homogeneous emphysema having the same treatment (MD 16.36%, 95% CI 9.02 to 23.71, p=0.00001, I²=0%, n=137, 2 RCTs).

In 3 RCTs (n=542) included in the SR there was a statistically significant increase in FEV₁ from baseline in patients without collateral ventilation treated by duckbill EBV (MD 18.15%, 95% CI 11.81 to 24.49; p=0.000001, I²=0%). Three RCTs (n=542) reported no statistically significant increase in FEV₁ after duckbill EBV treatment in patients with collateral ventilation (MD 2.48%, 95% CI −2.63 to 7.59, p=0.34, I²=0%). The SR reported that 2 RCTs showed statistically significant increases in FEV₁ in patients with intact interlobar fissures as a surrogate for the absence of collateral ventilation (MD 17.80%, 95% CI 7.78 to 27.82, n=68; and MD 17.23%, 95% CI 8.10 to 26.36, n=93). In an RCT of 97 patients without collateral ventilation, an increase in FEV₁ of greater than 12% from baseline was statistically significantly more frequent in patients treated by duckbill EBV (56% [36/64]) than in patients treated by SMC (3% [1/31], p<0.001) at 6‑month follow-up.

The SR reported a meta-analysis of 4 of the RCTs (n=379) of patients treated with duckbill EBV in whom the 6‑minute walking distance test was used to assess exercise capacity. The analysis showed a statistically significant increase in exercise capacity from baseline compared with SMC (MD 38.12 m, 95% CI 8.68 to 67.56, p=0.011, I²=78%).There was high variability between the studies. Three RCTs included in the SR reported a statistically significantly higher number of patients able to walk 26 m or more in the EBV-treated group compared with the SMC group. One RCT (n=321) found no statistically significant difference in the number of patients able to walk more than 26 m between the duckbill EBV and SMC groups (p=0.28). The SR reported a meta-analysis of 2 RCTs (n=316) that showed a statistically significant difference in exercise capacity from baseline favouring patients having SMC compared with patients treated by umbrella EBV (MD −19.54 m, 95% CI −37.11 to −1.98, p=0.029, I²=0%). In the RCT of 97 patients without collateral ventilation, an increase in 6‑minute walking distance of more than 26 m from baseline values was statistically significantly more frequent in patients treated by duckbill EBV (52% [33/63]) than in patients treated by SMC (13% [4/31], p<0.001) at 6‑month follow-up.

Five RCTs (n=695) included in the SR reported on quality of life measured by the St. George's respiratory questionnaire (SGRQ, 100 being the worst and 0 the best possible health status). In this analysis, patients treated by duckbill EBV had statistically significantly better quality of life than those having SMC (MD −7.29 units, 95% CI −11.12 to −3.45, p=0.0002, I²=67%) at a maximum follow-up of 12 months. The SR reported a meta-analysis of 2 RCTs (n=350) that showed no statistically significant difference in SGRQ score between patients treated by umbrella EBV and those having SMC (MD 2.64 units, 95% CI −0.28 to 5.56, p=0.076, I²=28%, high-quality evidence).

The specialist advisers listed the key efficacy outcomes to be lung function measurements, health status, exercise capacity, improvement in breathlessness, reduction in lung volume, and quality of life.