Experimental side-wall aneurysms: a natural history study

We studied the natural history of canine side-wall experimental aneurysms t o determine the incidence of spontaneous aneurysm thrombosis, to serve as c ontrol data for future studies focusing on development of aneurysm occlusio n devices. Bilateral common carotid artery vein patch aneurysms were surgic ally created in eight mongrol dogs (20-25 kg), Duplex Doppler sonography wa s performed at 13 days and angiography between 30 and 210 days following an eurysm creation. Sonography demonstrated patency of 13 (81%) of 16 aneurysm s. Patent aneurysms ranged in size from 8 x 10 mm to 14 x 16 mm. Convention al angiography was performed in four dogs approximately 30 days following a neurysm creation; in these four, all of 7 initially patent on sonography re mained fully patent. One dog underwent conventional angiography at approxim ately 60 days following aneurysm creation; both aneurysms in this case rema ined widely patent. Three dogs underwent conventional angiography at approx imately 200 days following aneurysm creation; all 4 aneurysms initially pat ent on sonography remained fully patent. None of the three aneurysms found to be occluded on sonographs demonstrated spontaneous recanalization. The c anine side-wall aneurysm model is a valid tool for testing some aneurysm-oc clusion devices, because control aneurysms remain patent indefinitely.