Factors associated with good response in a cohort of patients with severe emphysema and complete inter-lobar fissures undergoing endo-bronchial valve insertion

Background: Endo-bronchial valve insertion has become a recognised method of management in advanced emphysema. In patients who have undergone valve insertion response varies despite a rigorous selection process. The aim was to identify differences between responders and non-responders in a cohort of patients following endo-bronchial valve insertion. Methods: 25 patients who had undergone endo-bronchial valve insertion from June 2013 to December 2014 were included. Responders were defined as those where volume loss of the target lobe was complete (100%) or partial (over 50%) 30 days after the procedure. Baseline data included lung function tests, evidence of bullous emphysema in the target lobe, alpha 1 anti-trypsin (A1AT) deficiency status and flow analysis. Results: The mean age was 63 years and FEV1 of 29.9% predicted. 14 patients demonstrated a complete response, 2 partial response and 9 had no response. 5 patients had A1AT deficiency. Only 2/16 responders had bullous emphysema compared to 7/9 non-responders (p = 0.002). A decline of flow-over time (marker of absence of collateral ventilation) on catheter analysis was seen in 9/10 of the responders but only 2/7 in non-responders (p =0.035). Only 2 out of 5 patients with A1AT deficiency responded to treatment. Conclusions: Analysis identified that even with fissure completeness, patients with a significant bullous component of the target lobe may be more at risk of failure from endo-bronchial valve treatment. Absence of collateral ventilation is a useful predictor of response to treatment. A1AT deficiency is associated with a lower response rate.