HISTOLOGIC AND MORPHOLOGIC COMPARISON OF EXPERIMENTAL ANEURYSMS WITH HUMAN INTRACRANIAL ANEURYSMS

PURPOSE: Vein pouch aneurysms are the most commonly created experiment al lesions in neuroendovascular research. We sought to determine wheth er an experimental aneurysm that is derived from a pancreatic elastase -digested arterial sac (EDASA) models the histology and morphology of human cerebral aneurysms more accurately than the vein pouch aneurysm does. METHODS: EDASAs were created in the common carotid arteries of f our rabbits, and vein pouch aneurysms were created in the common carot id arteries of four pigs, Five recently ruptured human cerebral aneury sms were obtained at autopsy. Identical histologic preparations were m ade for all specimens, and a vascular pathologist performed blinded hi stologic analyses. Morphologic dimensions were measured with a microme ter at 40-fold magnification. RESULTS: In each human cerebral aneurysm , there was complete absence of internal elastic lamina and tunica med ia, and none showed evidence of mural inflammation or neointimal proli feration. Average wall thickness was 51 mu m. All vein pouch aneurysms had a well-developed internal elastic lamina and tunica media, and al l exhibited profound inflammation and neointimal proliferation. Averag e wall thickness was 290 mu m. EDASAs were devoid of internal elastic lamina, their tunica medias were mildly atrophic, and the sac walls co ntained only mild inflammation and neointimal proliferation. Average w all thickness was 46 mu m. CONCLUSIONS: EDASAs model the morphologic a nd histologic characteristics of human cerebral aneurysms more accurat ely than vein pouch aneurysms do.