Reversal of collateral ventilation using endoscopic polymer foam in COPD patients undergoing endoscopic lung volume reduction with endobronchial valves: a controlled parallel group trial

Background and objective: We have previously described reversal of collateral ventilation (CV) in a severe chronic obstructive pulmonary disease (COPD) patient with endoscopic polymer foam (EPF), prior to endoscopic lung volume reduction (ELVR) with valves. The aim of this study was to investigate the efficacy of this in a larger cohort and compare outcomes with a similar cohort with no CV. Methods: Patients with severe COPD, with the left upper lobe (LUL) targeted for ELVR, were assessed for CV with high resolution computed tomography (HRCT). If fissure completeness was >95% they were enrolled as controls for valves alone (endobronchial valve control group [EBV-CTRL]). If fissure completeness was 80%–95%, defects were mapped to the corresponding segment, where EPF was instilled following confirmation of CV with CHARTIS. EBVs were inserted 1 month afterwards. Results: Fourteen patients were enrolled into both arms. After 6 months, there were significant improvements in both groups in forced expiratory volume in 1 s (FEV1; +19.7% EPF vs. +27.7% EBV-CTRL, p < 0.05); residual volume (RV; −16.2% EPF vs. −20.1% EBV-CTRL, p = NS); SGRQ (−15.1 EPF vs. −16.6 EBV-CTRL p = NS) and 6 min walk (+25.8% EPF [77.2 m] vs. +28.4% [82.3 m] EBV-CTRL p = NS). Patients with fissural defects mapped to the lingula had better outcomes than those mapped to other segments (FEV1 +22.9% vs. +16.3% p < 0.05). There were no serious adverse reactions to EPF. Conclusion: EPF successfully reverses CV in severe COPD patients with a left oblique fissure that is 80%–95% complete. Following EBV, outcomes are similar to patients with complete fissures undergoing ELVR with EBV alone. EPF therapy to reverse CV potentially increases the number of COPD patients suitable for ELVR with minimal adverse reactions.