EXPERIMENTAL ASSESSMENT OF NEWLY DEVISED TRANSCATHETER STENT-GRAFT FOR AORTIC DISSECTION

Despite recent advances, surgical results for Stanford type B dissecti on are not yet satisfactory because the procedure is so highly invasiv e. The aim of this study was to devise a new intraaortic (IA) graft th at would offer less invasive treatment for type B dissection. To close the entry of type B dissections using transcatheter placement, we dev ised an IA graft (inner diameter, 15-20 mm; length, 40 to 60 mm) in wh ich a self-expandable stent was covered with a thin, open-cell-structu red polyurethane jacket. In acute animal experiments in which type B a ortic dissections were prepared in 4 mongrel dogs, IA grafts were impl anted to close the entry using a transfemoral catheter sheath, and clo sure of all the entries was confirmed by aortography. In chronic exper iments, five IA grafts for normal descending aortas and one IA graft f or an experimentally dissected aorta were implanted to observe histolo gic biocompatibility for up to 8 months. Histopathologic examination c onducted at the projected sacrifice periods revealed that endotheliali zation of the luminal surface of the IA graft had begun as early as 1 month after implantation and was completed within 4 months. The protot ype device that we developed may be promising as an effective, minimal ly invasive therapeutic intervention for closure of the entry site of type B dissection.