Endobronchial coils for severe emphysema are effective up to 12 months following treatment: medium term and cross-over results from a randomised controlled trial

Abstract

Background: There is a clinical need for therapeutic options to reduce hyperinflation associated with severe emphysema. Endobronchial Coils (coils) are nitinol devices implanted bronchoscopically under fluoroscopic guidance to re-tension the lung. We report the medium term effectiveness and safety of coils in a study of patients with emphysema.

Methods: Forty five subjects with severe airflow obstruction and hyperinflation received bilateral sequential treatment with coils (30 day interval between treatments) as part of a randomised controlled trial with a primary endpoint 90 days after the final treatment (Clinicaltrials.gov NCT01334307). Further assessments were made at 180 and 360 days and in this study the primary outcome was the effect of coil treatment on the St. George's Respiratory Questionnaire (SGRQ) 360 days following treatment.

Results: At 360 days following treatment, there was an improvement in the SGRQ score of -6.1±14.0 points (p = 0.01) compared to baseline. Improvements in secondary outcomes were seen with increases in forced expiratory volume in the first second of 8.9 ±22.2% (p = 0.002) and 6-minute walking distance of 34.1±52.4m (p = 0.003). The safety profile was acceptable out to 360 days post-treatment.

Conclusions: Statistically and clinically meaningful benefits in quality of life, exercise capacity and pulmonary function in patients treated with coils are sustained twelve months after treatment.

Trial registration information: Clinicaltrials.gov NCT01334307.

Conflict of interest statement

Competing Interests: PLS and SVK have received honoraria from PneumRx for lecturing at independent meetings. SVK and ZZ have received travel grants. The remaining authors have no conflicts of interest to declare. This does not alter the authors' adherence to PLOS ONE policies on sharing data and materials and there are no restrictions on sharing of data and/or materials.

Figures

Fig 1. Flow diagram for the study.

The primary endpoint in this study is the change in St. George’s Respiratory Questionnaire (SGRQ) [19] at 360 days post final treatment. A change of four points is widely accepted to be the minimally clinically important difference (MCID).[20] Pulmonary function tests including whole body plethysmography were performed as per international guidelines using the European Community of Coal and Steel Workers’ cohort normal values.[21] The 6 minute walk distance (6MWD) was performed according to ATS guidelines.[22] These assessments were performed at each non-treatment visit.

Fig 2. Efficacy outcomes in the coil treated patients 90, 180 and 360 days post final treatment.