Clinical and quantitative computed tomography predictors of response to endobronchial lung volume reduction therapy using coils.

Abstract

ObjectivesBronchoscopic lung volume reduction using coils (LVRC) is a well-known treatment option for severe emphysema. The purpose of this study was to identify quantitative computed tomography (QCT) and clinical parameters associated with positive treatment outcome.Patients and methodsThe CT scans, pulmonary function tests (PFT), and 6-minute walk test (6-MWT) data were collected from 72 patients with advanced emphysema prior to and at 3 months after LVRC treatment. The procedure involved placing 10 coils unilaterally. Various QCT parameters were derived using Apollo imaging software (VIDA). Independent predictors of clinically relevant outcome (Δ6-MWT ≥ 26 m, ΔFEV1 ≥ 12%, ΔRV ≥ 10%) were identified through stepwise linear regression analysis.ResultsThe response outcome for Δ6-MWT, for ΔFEV1 and for ΔRV was met by 55%, 32% and 42%, respectively. For Δ6-MWT ≥ 26 m a lower baseline 6-MWT (p = 0.0003) and a larger standard deviation (SD) of low attenuation cluster (LAC) sizes in peripheral regions of treated lung (p = 0.0037) were significantly associated with positive outcome. For ΔFEV1 ≥ 12%, lower baseline FEV1 (p = 0.02) and larger median LAC sizes in the central regions of treated lobe (p = 0.0018) were significant predictors of good response. For ΔRV ≥ 10% a greater baseline TLC (p = 0.0014) and a larger SD of LAC sizes in peripheral regions of treated lung (p = 0.007) tended to respond better.ConclusionPatients with lower FEV1 and 6-MWT, with higher TLC and specific QCT characteristics responded more positively to LVRC treatment, suggesting a more targeted CT-based approach to patient selection could lead to greater efficacy in treatment response.