Are covered stents really effective at closing esophagotracheal fistulas? Results of an animal study

Purpose: To determine whether covered self-expanding metal stents successfu lly exclude experimentally created esophagotracheal fistulas. Methods: Esophagotracheal fistulas were surgically created in the upper thi rd of the esophagus in 12 minipigs and immediately sealed by implantation o f a covered self-expanding metal stent (20 mm expanded diameter) in the eso phagus. Before the animals were killed, after 3, 7, 14, 28, 30, and 36 days , the position of the stent and the sealing of the fistula were monitored f luoroscopically. The esophagus, trachea, and both lungs were examined histo logically. Results: Creation of an esophagotracheal fistula was successful in all case s. All fistulas were widely patent at autopsy. The technical success rate f or stent deployment and initial sealing of the fistula was 100%. During fol low-up, five stents migrated distally, but none into the stomach. Therefore , the fistula was no longer excluded in five animals. In seven animals the stent sealed the fistula until the death of the animal. Tracheal narrowing necessitated additional tracheal stenting in three animals. Two minipigs di ed due to aspiration of food. Histologic examination showed signs of aspira tion in all animals with stents in place for longer than 2 weeks. Conclusion: This experimental animal study revealed worse results for seali ng of esophagotracheal fistulas with covered self-expanding metal stents th an have been reported for the clinical use of these devices.