Chronic vascular changes in the walls of experimental berry aneurysms of the aortic bifurcation in rabbits.

Experimental berry aneurysms were fashioned from an autogenous venous transplant by microvascular surgery at the aortic bifurcation of rabbits maintained on a stock diet. Structural changes in the aneurysms and in the host aorta were studied for periods up to 3 years 9 months postoperatively. Phlebosclerosis developed in the aneurysms and progressed to severe fibrosis, calcification, ossification, mural thrombosis and lipid deposition resembling human atherosclerosis, with eventual loss of the media. The host aorta exhibited pronounced intimal thickening at the bifurcation. The experiments demonstrated the importance of hemodynamic stress in the accelerated production of the degenerative changes in the walls of berry aneurysms.