Efficacy of the Spiration Valve System in Patients with Severe Heterogeneous Emphysema: A Systematic Review and Meta-Analysis

Background: Spiration Valve System (SVS) is an alternative for patients with severe heterogeneous emphysema; however, data about efficacy from randomized controlled trials (RCT) are unclear. Objectives: To explore both efficacy and safety of SVS in patients with severe emphysema and hyperinflation. Methods: We included PubMed, EMBASE, Coch­rane database. All searches were performed until August 2019. Only RCTs were included for analysis. Risk of bias was assessed using Cochrane risk of bias tool. A meta-analysis evaluated change in forced expiratory volume in 1 s (FEV 1 ), 6-min walking test (6MWT), residual volume, modified medical research council (mMRC) and Saint George respiratory questionnaire (SGRQ), all-cause mortality, risk of pneumothorax, and risk of acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Quality of the evidence was rated using GRADE approach. Results: Four RCTs including 629 subjects were included. SVS showed an overall change of 0.03 L (–0.07 to 0.13, I 2 = 90%) in the in FEV 1 (L) and a 2.03% (–2.50 to 6.57, I 2 = 96%) in the predicted FEV 1 (%) compared to baseline; however, studies without collateral ventilation (CV) showed an improvement of 0.12 L (95% CI 0.09–0.015, I 2 = 0%), This subgroup also reported better results in SGRQ –12.27 points (95% CI –15.84 to –8.70, I 2 = 0%) and mMRC –0.54 (95% CI –0.74 to –0.33, I 2 = 0%). We found no benefit in 6MWT mean difference = 4.56 m (95% CI –21.88 to 31.00, I 2 = 73%). Relative risk of mortality was 2.54 (95% CI 0.81–7.96, I 2 = 0%), for pneumothorax 3.3 (95% CI 0.61–18.12, I 2 = 0%) and AECOPD 1.68 (95% CI 1.04–2.70, I 2 = 0%). Conclusion: In patients with severe heterogeneous emphysema and hyperinflation without CV, SVS is an alternative that showed an improvement in pulmonary function, quality of life, and dyspnea score with an acceptable risk profile.