Study objectives: To evaluate the histocompatibility of four different materials used to cover expandable metallic stents.
Design: Prospective, randomized, unblinded study.
Setting: Animal research laboratory of Kurume University.
Patients or participants: Twenty 12- to 18-kg mongrel dogs.
Interventions: Handmade Gianturco-type stents with six bends, 20 mm in length, and 15 to 20 mm in diameter were covered using four different materials: polypropylene mesh, silicone-coated mesh, polyester mesh, and ePTFE. Covered stents were inserted into the trachea after IV anesthesia. Five animals were used in each group.
Measurements and results: Postinsertion status was observed using clinical and bronchoscopy measures 7, 14, 28, and 56 days after intervention. Eight weeks after stent insertion, the tracheal specimens were studied pathologically. A scoring system was used to evaluate the histocompatibility of covered stents in each study group. The mean of clinical scores in the polypropylene group was 1.84±0.36, which was significantly higher than those in the groups of silicone, polyester, and ePTFE. The means of histopathologic scores in the polypropylene group and the silicone group were 1.60±0.55, which were significantly higher than those in groups of polyester and ePTFE.
Conclusions: Polypropylene mesh cover was more suitable than silicone-coated mesh, polyester mesh, and ePTFE because of its excellent histocompatibility.