Complicated atherosclerotic plaques in the aortic arch represent an independent risk factor for systemic embolism similar to atrial fibrillation and severe atherosclerosis of the carotid arteries.

Ulcers in extracranial carotid arteries are a known source of cerebral embolism. However, there are no data available on the prevalence of ulcerations located at the origin of these vessels in the aortic arch. Therefore, in this pathological study the topographic distribution of ulcerated lesions were determined in these arteries. One hundred and one consecutively autopsied patients composed the study group. Ulcerated plaques were sought for in both carotid arteries, from their origin in the arch up to the carotid canal, and also in the aortic arch and ascending aorta. The two anatomical sites mostly affected by atherosclerosis were the region of the carotid sinus and the orifices of cervical arteries in the aortic arch. More than one third of all ulcers were at the orifices of cervical arteries in the arch. Interestingly, ulcers at the orifice of the left common carotid artery in the arch were accompanied with other ulcers located elsewhere in the remaining segments of the left carotid system, whereas ulcerations at the orifice of brachiocephalic trunk were not accompanied with other concomitant lesions in the right carotid system. Furthermore, there was no symmetric distribution of ulcerated plaques in both carotid systems.

The significance of the thoracic aorta as a source of systemic emboli in addition to other sources of embolism remains unexplained. A study of 120 consecutive necropsies (65 men, 55 women; mean age 71 [29-94] years) analysed the possible correlation of the severity of arteriosclerosis of the aorta, the carotid arteries and the arteries at the base of the brain as well as cardiac changes, with potential sources of emboli and with proven emboli (n = 39). Complex and fibrous plaques in the arch of the aorta, ipsilateral carotid artery stenoses, a history of atrial fibrillation and heart weight correlated significantly with emboli on both uni- and multivariant analysis. But the presence of calcified and complex plaques in the descending aorta, as well as moderate and severe arteriosclerosis in the arteries at the base of the brain, correlated significantly only on univariant analysis. Ischaemic brain lesions had been clinically silent in twelve of 32 cases, while visceral emboli had been silent in nine out of ten cases. -It is concluded from these data that, in addition to the cardiac chambers and arteriosclerosis of the arteries at the base of the brain, advanced arteriosclerosis of the aortic arch is an important source of systemic emboli. As many of the emboli remain silent, their incidence is probably underestimated clinically.