Intrabronchial valves are being evaluated in patients for palliative treatment of advanced emphysema. Any object placed in the airway increases the risk of infection. One-year implants of Intra-bronchial Valves (IBV, Spiration Inc.) in a canine model showed no evidence of pulmonary infection and insignificant bacterial culture yields. A sheep model with greater sensitivity was used to challenge the IBV and evaluate the incidence of pulmonary bacterial colonization and infections.
Using flexible endoscopy, 16 sheep were implanted with IBV to produce LVR. The health of all animals was monitored for the duration of the study and blood samples were obtained at baseline, implant and follow-up procedures. Groups of 4 animals were evaluated and terminated at 1, 3, 6 and 13 months. At necropsy, swab cultures, via incision, were obtained from lung lobes treated with valves and one or more control areas. Histology was also performed.
All animals were healthy for the duration of the study. There were no abnormalities on the blood work. A total of 216 valves were placed. Necropsy showed no evidence of infection on gross inspection. Cultures from a total of 132 sites were taken. In each animal, an average of 8±2 sites were cultured: 3±2 samples showed positive and 5±2 negative culture results. The most common positive aerobic cultures were: pseudomonas aeruginosa in 7 and pasteurella multocida in 5 animals. Positive mycoplasma was observed in 7 animals. One culture obtained from a control area was positive. There were minimal histologic changes to the airways where the devices were implanted.
In this sheep model, the IBV and/or volume reduction was associated with microbial colonization in one third of the areas treated, but these areas were without clinical infection.
Incidence of post-obstructive pneumonia associated with airway devices may be minimized by a non-stent device design that has mild effects on airway mucosal structure and function.
X. Gonzalez, Spiration Inc