Respiratory infections increase the risk of granulation tissue formation following airway stenting in patients with malignant airway obstruction

Abstract

Background: The most serious complications of airway stenting are long term, including infection and granulation tissue formation. However, to our knowledge, no studies have quantified the incidence rate of long-term complications for different stents.

Methods: To compare the incidence of complications of different airway stents, we conducted a retrospective cohort study of all patients at our institution who had airway stenting for malignant airway obstruction from January 2005 to August 2010. Patients were excluded if more than one type of stent was in place at the same time. Complications recorded were lower respiratory tract infections, stent migration, granulation tissue, mucus plugging requiring intervention, tumor overgrowth, and stent fracture.

Results: One hundred seventy-two patients with 195 stent procedures were included. Aero stents were associated with an increased risk of infection (hazard ratio [HR] = 1.98; 95% CI, 1.03-3.81; P = .041). Dumon silicone tube stents had an increased risk of migration (HR = 3.52; 95% CI, 1.41-8.82; P = .007). Silicone stents (HR = 3.32; 95% CI, 1.59-6.93; P = .001) and lower respiratory tract infections (HR = 5.69; 95% CI, 2.60-12.42; P < .001) increased the risk of granulation tissue. Lower respiratory tract infections were associated with decreased survival (HR = 1.57; 95% CI, 1.11-2.21; P = .011).

Conclusions: Significant differences exist among airway stents in terms of infection, migration, and granulation tissue formation. These complications, in turn, are associated with significant morbidity and mortality. Granulation tissue formation develops because of repetitive motion trauma and infection.

Figure 1.

Kaplan-Meier plot of time to first respiratory infection by stent type. Aero stents (dashed line) had a significantly shorter time to infection than did other stents (P = .043).

Figure 2.

Kaplan-Meier plot of time to migration by stent type. Silicone tube stents (dashed line) had a higher incidence of stent migration than did non-silicone tube stents (solid line). Y-shaped stents are excluded from this analysis.

Figure 3.

Kaplan-Meier plot of time to granulation tissue formation. Both Aero stents (dashed line) and silicone stents (dotted line) had a higher incidence of granulation tissue formation than did Ultraflex stents (solid line).