Mobile Thromboses of the Aortic Arch Without Aortic Debris

Background Atherosclerotic lesions of the aortic arch are potential sources of arterial embolism. Mobile thrombi in the aortic arch in young patients without diffuse atherosclerosis have been reported recently, but such cases remain exceptional. We describe a series of young patients with unexplained arterial embolism in whom transesophageal echocardiography detected mobile aortic arch thromboses. Methods and Results Transesophageal echocardiography files collected between 1991 and 1995 in French academic cardiology centers were reviewed to identify patients who fulfilled the following criteria: (1) an arterial embolic event in the preceding weeks; (2) a mobile pedunculated aortic arch thrombosis, defined as an echogenic mass protruding into the lumen of the aorta and inserted on the aortic arch; and (3) absence of obvious diffuse aortic atherosclerosis or of aortic debris on transesophageal echocardiography. Twenty-three cases were identified from 27 855 examinations. Thromboses were located on the horizontal aorta (n=4), near the ostium of the left subclavian artery (n=5), or on the concavity of the posterior segment of the aortic arch (in the isthmus) (n=14). The insertion site was a small atherosclerotic plaque in 21 patients. The remaining aortic wall always appeared normal or mildly atherosclerotic. The mean age of the patients was 45±8.4 years (range, 26 to 61 years). All patients were treated with intravenous heparin after the diagnosis of aortic arch thrombosis, and surgical removal of the thrombosis was performed in 10 patients in whom histological examination confirmed an atherosclerotic process at the site of insertion of the thrombosis. The prognosis was mainly influenced by embolic events. Conclusions Thromboses of the aortic arch appear to be a variant form of aortic atherosclerotic disease associated with arterial embolism in young patients.