Evaluation of aneurysm models, particularly of the aorta and cerebral arteries

Irrespective of their intended use, the best models of spontaneous aneurysms in humans are produced under conditions analogous to those occurring in humans and specific for the site. Even if appropriate for other purposes, models dependent on artificial conditions (physical and thermal trauma, chemical and enzymatic degradative processes), not in compliance with the above, bear no relationship to the etiology or pathology of the lesion or disease under investigation. Surgical models of poststenotic dilatation and aneurysm, arteriovenous shunts, and venous graft aneurysms are suitable for study of the prevailing hemodynamics and pathological effects of the associated stresses on the vessel wall which have bearing on degenerative aneurysms at other sites. The protracted course of atherosclerosis and constraints of time and research funds when reproducing the pathology and conditions prevailing in the human situation legitimize the use of models which accelerate development and complications. The limitations of any model are of paramount consideration. The value of some current models of aortic and cerebral aneurysms is discussed.