Atherosclerosis of the aorta as a source of arterial embolisms

Abstract

Aortic atherosclerosis has early been recognized as a potential source of embolism. The histological finding of cholesterol clefts in small end-arteries characterized the entity of cholesterol embolism. The clinical picture was extremely variable and the diagnosis was frequently established post-mortem or by means of invasive although insensitive procedures including biopsy and angiography. Therefore, cholesterol embolism was thought to be rare. With the routine use of transesophageal echocardiography for the diagnostic workup of arterial embolism, aortic atherosclerosis was shown to be the source of otherwise unexplainable embolism. Cross-sectional studies demonstrated an independent association between prominent plaques of more than 4 to 5 mm of thickness or plaques with mobile components in the aortic arch. In follow-up studies, the risk of embolic events in patients with this kind of lesions exceeded 10% per patient-year. The results of pathological studies were consistent with these findings showing that ulcerated complex plaques carry an independent risk for embolic events. Apart from spontaneous embolism, atherosclerosis of the proximal aorta was shown to be a cause of embolic complications during cardiac surgery and catheterization procedures which involve the aorta. Medical treatment for the prevention of embolism in atherosclerotic disease of the aorta has not been studied systematically. In a variant form of aortic atherosclerosis consisting of mobile pedunculated thrombi inserting on relatively small plaques, anticoagulant therapy has proved to be useful in small numbers of patients. Recurrent embolic events could be prevented and regression of the thrombotic masses has been observed.