[Latex covering and mechanical analysis of balloon expandable stents]

To the moment a few stents of metallic coils or meshes are available with a sealing coverage. In the present study balloon-expandable stents have been covered with a thin layer of natural rubber latex. The physical properties of these impervious stents were compared to the conventional stents. The expansion, the loss of expansion and the deformity during and after balloon inflation have been analyzed. In the pressure zone of 4-6 bar the mechanical characteristics of the impervious stents were similar to the conventional stents. The stents were expanded at 100% related on the balloon diameter used for expansion. Additional pressure of 1 bar was necessary to expand the impervious stents. At balloon pressure below 4 bar the stents tied the balloons in the midzone. The impervious stents, expanded at 6, 8 and 10mm, underwent a loss of expansion of 10% after withdrawal of the balloons. Their configuration was barrel-shaped (4% central enlargement) due to the latex rubber, constricting the wire meshes at both ends. These preliminary results are encouraging and allow further investigations.