Figure 1.

Angiographic and histologic results one year after coiling of experimental aneurysms with bare coils (upper row), Matrix ^® coils (middle row) and HydroCoils ^® (lower row). Angiography demonstrates complete occlusion in all three animals despite a rather loose packing in the animal treated with Hydrogel-coated coils. Histology (middle row) demonstrates in the bare coil group that the aneurysm fundus was completely occluded with fibrinous and collageneous extracellular matrix and granulation tissue, however, surrounding the coil loops at the aneurysm orificium (right row) there is only a thin layer of fibrinous tissue and no neoendothelium present. The Matrix Coils did not show a complete neoendothelial layer bridging the aneurysm neck, however, as demonstrated in the right image of the middle row, a beginning layering of neointima and neoendothelium was present over the aneurysm neck. It was only in the Hydrogel-coated coils that a complete neoendothelialization was present with a neointima spanning the coil loops at the aneurysm neck leading to a complete exclusion of the aneurysm form the circulation.