Prolongation of patency of airway bypass stents with use of drug-eluting stents

Abstract

Objective: Airway bypass by transbronchial fenestration has been shown to improve forced expiratory volume and flow in explanted emphysematous human lungs. We previously demonstrated the feasibility and safety of airway bypass stent placement in a canine model, but we found that most stents occluded within 1 week. The aim of this study was to evaluate the influence of controlled-release paclitaxel-eluting stents on prolongation of patency.

Methods: With the subject dogs under general anesthesia, suitable segmental and subsegmental bronchial wall sites were selected by direct visualization with a flexible bronchoscope. A Doppler probe was used to detect and avoid sites with adjacent blood vessels. Transbronchial passages were formed with a 25-gauge transbronchial needle-tipped catheter and dilated with a 2.5-mm balloon integrated into the needle catheter. A specifically designed expandable stainless steel stent (3 mm long x 3 mm wide) embedded in a sleeve of silicone rubber was placed within the passage and expanded until secured about the bronchial wall. Fifty control stents (no paclitaxel impregnation) and 107 paclitaxel-eluting stents were placed in 25 dogs. Animals underwent bronchoscopy at intervals to assess stent patency.

Results: Eight instances of minor and brief bleeding occurred during stent placement; all resolved without incident. There were no pneumothoraces or deaths associated with stent placement. No delayed complications occurred. No identifiable paclitaxel-related toxicity was observed. At 1, 4, 8, and 12 weeks, the patency rates were 10%, 0%, 0%, and 0% for control stents and 100%, 96%, 76%, and 65% for paclitaxel stents.

Conclusion: In an animal model, the use of specifically designed paclitaxel-eluting airway bypass stents was both feasible and safe. These stents resulted in a significant prolongation of patency.