The localized inflammatory response to bronchoscopic thermal vapor ablation.

BACKGROUND Bronchoscopic thermal vapor ablation (BTVA) reduces lung volumes in emphysema patients by inducing a localized inflammatory response (LIR) leading to a healing process of fibrosis, but may also increase symptoms. OBJECTIVES We sought to evaluate whether the clinical manifestation of LIR correlated with patient outcome. METHODS Respiratory adverse events and inflammatory markers were analyzed from a multicenter trial of BTVA in patients with upper-lobe-predominant emphysema. End points including changes in forced expiratory flow (FEV1), lobar volume, St. George's Respiratory Questionnaire (SGRQ), modified Medical Research Council (mMRC) and 6-minute-walk distance (6-MWD) were analyzed according to the presence or absence of a respiratory adverse event requiring treatment with an antibiotic or steroid. RESULTS Forty-four patients received BTVA. Increases of inflammatory markers were observed with a peak between the second and fourth week. Eighteen respiratory adverse events occurred in 16 patients within 30 days of BTVA, requiring antibiotics and/or steroids. These patients had significantly greater lobar volume reduction (65.3 vs. 33.4%, p = 0.007) and a change in residual volume at 12 months (-933 vs. 13 ml, p < 0.001) associated with a greater improvement of exercise capacity and health-related quality of life than patients without respiratory adverse events. CONCLUSION Patients with more prominent respiratory symptoms in the first 30 days following BTVA experience greater efficacy. The clinical manifestations of the LIR are predictive of long-term clinical benefits.