ATHEROSCLEROTIC DISEASE OF THE AORTIC-ARCH AND THE RISK OF ISCHEMIC STROKE

Background. Atherosclerotic disease of the aortic arch has been suspec ted to be a potential source of cerebral emboli. We conducted a study to quantify the risk of ischemic stroke associated with atheroscleroti c disease of the aortic arch. Methods. Using transesophageal echocardi ography, we performed a prospective case-control study of the frequenc y and thickness of atherosclerotic plaques in the ascending aorta and proximal arch in 250 consecutive patients admitted to the hospital wit h ischemic stroke and 250 consecutive controls, all over the age of 60 years. Results. Atherosclerotic plaques greater than or equal to 4 mm in thickness were found in 14.4 percent of the patients but in only 2 percent of the controls. After adjustment for atherosclerotic risk fa ctors, the odds ratio for ischemic stroke among patients with such pla ques was 9.1 (95 percent confidence interval, 3.3 to 25.2; P<0.001). A mong the 78 patients who had brain infarcts with no obvious cause, 28. 2 percent had plaques greater than or equal to 4 mm in thickness, as c ompared with 8.1 percent of the 172 patients who had infarcts whose po ssible or likely causes were known (odds ratio, 4.7; 95 percent confid ence interval, 2.2 to 10.1; P<0.001). Plaques of greater than or equal to 4 mm in the aortic arch were not associated with the presence of a trial fibrillation or stenosis of the extracranial internal carotid ar tery. In contrast, plaques that were 1 to 3.9 mm thick were frequently associated with carotid stenosis of greater than or equal to 70 perce nt. Conclusions. These results indicate a strong, independent associat ion between atherosclerotic disease of the aortic arch and the risk of ischemic stroke. The association was particularly strong with thick p laques. Atherosclerotic disease of the aortic arch should be regarded as a risk factor for ischemic stroke and as a possible source of cereb ral emboli.