Granulation tissue formation following dumon airway stenting: The influence of stent diameter

Objectives: The present study aimed to determine whether stent diameter influences granulation tissue formation following stent placement for major airway stenosis. Patients and Methods: Forty-two stent procedures (32 tracheal stents, 3 carinal stents, and 7 bronchial stents) were performed in 40 patients. Seventy-nine stent edge regions (62 tracheal, 17 bronchial stents) were evaluated in this study. Results: Granulation tissue formation was encountered in 11 patients (28.21 %). Of the 34 upper ends of evaluated tracheal stents, granulation tissue formation was observed in 6 (17.65 %), whereas granulation tissue formation was observed in 2 (7.14 %) of the 28 lower ends of tracheal stents evaluated. Of the 17 bronchial stent edge regions, granulation tissue formation occurred in 3 (17.65 %) (p = 0.4352). The rate of granulation tissue formation was higher in those patients with a stent-to-airway diameter ratio of > 90 % (p < 0.0001). Receiver operating characteristic curve analysis further demonstrated that a cut-off stent-to-airway diameter ratio of 90 % was effective in predicting granulation tissue formation (AUC: 0.897, Std. error = 0.036, p < 0.0001, 95 % CI = 0827-0.968, n = 79). Conclusions: A stent-to-airway diameter ratio of 90 % was found to be the critical cut-off point for predicting granulation tissue formation. Therefore, the optimal stent-to-airway diameter ratio should be ascertained before stent placement.