Over the last several years, numerous trials have been carried out to check the efficacy of one-way valves in the management of advanced emphysema. While the design of the valves has not altered much, by selectively studying these valves in a select group of participants, such as those with and without intact fissures (FI+ and FI-), and by using different procedural techniques, our understanding of the valves has evolved. In this meta-analysis, we sought to study the effect of these factors on the efficacy of one-way valves. From PubMed and Embase, we included only those studies that provided separate data on fissure integrity or collateral ventilation. Our study outcomes included the mean change in forced expiratory volume in first second (FEV1), 6-minute walk distance (6MWD) and the St George's Respiratory Questionnaire (SGRQ). In the FI+ subgroup of participants, the pooled standardized mean difference in FEV1, 6MWD, and SGRQ were 0.50 (95% confidence interval (CI): 0.34 to 0.67), p ≤ 0.001, 0.29 (95% CI: 0.13 to 0.45), p ≤ 0.001 and -6.02 (95% CI: -12.12 to 0.06), p = 0.05, respectively. In comparison, these results were superior to the FI- subgroup of participants. A separate analysis of the FI+ subgroup based on lobar occlusion versus nonlobar occlusion favored the former for superior efficacy. The preliminary findings of our meta-analysis confirm that one-way valves perform better in a select group of patients who show intact fissures on lung imaging pretreatment and in those who achieve lobar occlusion.
Keywords: Endobronchial valves; bronchoscopy; chronic obstructive pulmonary disease; emphysema; lung volume reduction; meta-analysis.
© The Author(s) 2014.