Radiation damage to large arteries.

Little is known about late changes in large arteries after radiotherapy. Much more is known about damage to other organs and tissues. The arterial changes resemble chronic, progressive atherosclerosis which may be due to a combination of periarterial fibrosis, direct damage to the arterial wall, occlusion of vasa vasorum and acceleration of naturally occurring atherosclerosis. Factors that may predispose to arterial occlusion that relate to radiotherapy include maximum tissue dose, beam energy and field size. The authors present four patients with axillary artery occlusion that occurred 10 to 27 years after mastectomy and irradiation. The axillary artery is seldom affected by segmental atherosclerotic occlusive disease. Hence, the cause of the occlusion was most likely the irradiation. All patients did well after bypass grafting.