Utilizing the external jugular vein graft, veinpouch aneurysm of 6 to 9mm in orifice and of 5 to 8mm in height was made on the common carotid artery of the dog. Longitudinal incision of 8 to 12mm in length was made in the artery instead of “V” incision used by German and Black. The open end of the vein-pouch graft was cut obliquely and sutured to the arterial incision to make an angle of 65 to 70° between the aneurysm and the artery.
Intraaneurysmal hemodynamics was observed through thin wall of the aneurysm with highspeed 16mm movie. Jet flow was seen at the dome of the aneurysm, corresponding to each systole. Turbulence was most remarkable on the distal side of the aneurysmal sack. These flows were markedly reduced by mechanical stenosis of the parent artery on the cardiac side, which decreased arterial flow to 50% of the resting value, and they were completely abolished by carotid occlusion. Following carotid occlusion, intraaneurysmal mean pressure was reduced to 71% of the original level on an average and pulse pressure was decreased to 0 to 5mmHg.
Patency of these vein-pouch aneurysms was evaluated on angiogram. One week after the aneurysm had been made, approximately 80% of the aneurysms which had the larger orifice than their was completely patent. No intraaneurysmal thrombus formation nor stenosis of the parent artery was revealed by angiogram. All aneurysms which were completely patent at this point remained under the same state during the follow-up of 1 month.
Histological examination cofirmed that the junction between the vein-pouch and the artery was covered smoothly with a layer of endothelium extending from the artery. No degenerative change of the aneurysmal wall nor thrombus formation was found.
This vein-pouch aneurysm may be one of most desirable experimental models for study on intraaneurysmal hemodynamics and treatment of an intracranial aneurysm.
