A New Self-Expanding, Removable, Covered Metal Tracheobronchial Stent: Results of an Animal Trial

Abstract

Background Tracheobronchial airway stents are increasingly being used to palliate malignant and benign obstruction of central airways. Metallic stents overcome many of the drawbacks of silicone stents. However, because of the excessive granulation tissue (GT) formation, longer these metallic stents are in place, more difficult it is to remove them and more problems they create. Objectives To evaluate airway tolerance of a new hybrid stent meant to capture the advantages of both silicone and metal stents in an animal model known to be prone to develop acute airway inflammation with metallic stents. Methods Study stents (Alveolus AERO) and control stents (Ultraflex stent, Microvasive, Boston Scientific Corporation, Natick, MA) were implanted in the trachea of 8 piglets. Proximal and distal implantation sites were randomly alternated between study and control stents within the same pig. Fourteen and 28-day bronchoscopic follow-up allowed assessment of airway tolerance of the stents with special focus on GT formation and ease of stent removal. Results Study stents produced nothing but mild GT, removal was easy. Control stents in contrast showed moderate or severe inflammatory reactions, which made removal of the stent difficult in 3 cases and impossible in 2 cases. Conclusions The new hybrid stents cause less GT in the short term in an animal model. Complications of long-term stent placement and migration need to be assessed.