Factors leading to obstructive granulation tissue formation after ultraflex stenting in benign tracheal narrowing

This retrospective study aimed to determine the factors leading to obstructive granulation tissue formation after the placement of a self-expandable metallic stent (SEMS) in patients with benign tracheal disease.

From 2001 to 2007, a total of 67 patients (age: 62.1 +/- 15.4 years; range: 23-87 years) with benign tracheal disease received 75 ultraflex SEMS in our institution.

There were 35 SEMSs complicated by obstructive granulation tissue formation out of the 75 stents placed in patients with tracheal disease, giving an incidence of 47.8 % (32/67 patients). The median time until developing granulation tissue was 106 days (IQR, 46-396). Structural airway obstruction prior to SEMS implantation independently predicted obstructive granulation tissue formation after SEMS implantation (odds ratio: 3.84; 95 % CI: 1.01-8.7; P = 0.04). Time to granulation tissue detection was shorter in patients with structural airway obstruction before SEMS implantation (structural airway obstruction vs. dynamic collapse airway: median [IQR] 95 [38-224, n = 26] vs. 396 days [73-994, n = 9]; P = 0.02).

Obstructive granulation tissue formation is not uncommon after SEMS implantation and structural airway obstruction prior to SEMS implantation is an independent predictor. Although SEMS implantation should be restricted to a select population, it may be placed in patients not suitable for surgical intervention or rigid bronchoscopy with anesthesia because of poor pulmonary function.