SESSION TYPE: Bronchology Case Report Posters
PRESENTED ON: Tuesday, October 23, 2012 at 01:30 PM - 02:30 PM
INTRODUCTION: Airway Stents are commonly used for the treatment of tracheobronchial strictures. We present an unusual case of Aero (Merit Endotek) stent failure, leading to partial airway obstruction.
CASE PRESENTATION: The patient is a 63 year old white female with severe emphysema status post left single lung transplant in 2004. Due to longstanding acquired severe symptomatic tracheomalacia, she had an Aero type hybrid self-expanding metallic stent placed in November 2008 at an outside institution. She presented to our facility with acute dyspnea in April 2009. Chest imaging showed a new vertical linear density along the left stent margin. Given prior history of lung transplant and suspicion of stent fracture, bronchoscopy was performed. At flexible bronchoscopy, she was noted to have collapse of the stent, with marked in-folding of the posterior portion, dividing the lumen along the entire length of the stent and causing partial airway obstruction. The bronchoscope could just barely pass through one of the lumens of the obstruction. Rigid bronchoscopy (RB) was performed. The fractured stent was removed and replaced with a Polyflex stent. The removed stent appeared to have a ridge of fractured wires and was completely folded upon itself longitudinally.
DISCUSSION: Polyflex stents (Boston Scientific) are made with silicone and polyvinyl chloride, self expand on deployment, and are typically placed using RB. Self expanding metallic stents (SEMS) have the advantage of placement under flexible bronchoscopy as well as less migration risk. However, typical SEMS are very difficult to remove. “Hybrid” SEMS are made of a nitinol mesh embedded in silicone, which is purported to decrease epithelialization and allow for repositioning or removal after placement [1,2]. In the current case it is suspected that factors leading to the stent failure include the following: (a) The nitinol mesh design of the Aero stent appears to have weak points; (b) The hybrid nature of the stent prevents epithelialization, and therefore external forces, such as cough, are not sufficiently diffused across the entire airway/stent complex; and (c) placement in the trachea subjects this stent to higher and more repeated stressors. In this particular case we used a silicone stent in the trachea as we believe that current SEMS cannot withstand tracheal forces and are at higher risk of fracture.
CONCLUSIONS: This case illustrates some of the background concerns which brought about the FDA’s warning on placement of metallic stents in the trachea.
1) Chin CS, Litle V, Yun J, Weiser T, Swanson SJ. Airway stents. Ann Thorac Surg. 2008 Feb;85(2):S792-6.
2) Dooms C, De Keukeleire T, Janssens A, Carron K. Performance of fully covered self-expanding metallic stents in benign airway strictures. Respiration. 2009;77(4):420-6.
DISCLOSURE: The following authors have nothing to disclose: Syed Gilani, Kamran Manzoor, Michael McCormack, Paul Branca
No Product/Research Disclosure InformationUniversity of Tennessee Medical Center, Knoxville, TN