PURPOSE: Arterial thromboembolism in patients with an unknown source of embolization is still associated with significant morbidity and mortality. The advent of transesophageal echocardiography (TEE) and magnetic resonance imaging (MRI) and the more frequent use of computed tomography (CT) have led to the identification of mural aortic thrombi (MAT) as a source of distal embolization in a much higher proportion of patients than previously appreciated. The incidence, diagnosis, and treatment of patients with MAT is reported. METHODS: In a prospective study, from January 1996 to December 1998, 89 patients with acute embolic events underwent an extensive diagnostic workup, consisting of TEE, CT, or MRI, to detect the source of embolization. Patients in whom the heart (n = 51), occlusive aortoiliac disease (n = 16), or aortic aneurysms (n = 12) was identified as the source of embolization were excluded. RESULTS: Five female and three male patients, with a median age of 63 years (range, 35 to 76 years), with bilateral or repetitive embolic events resulting from MAT were identified, representing 9% of all patients with arterial thrombembolism. All patients had several risk factors for atherosclerosis, but only one young patient had a single risk factor that promoted thrombosis. Successful percutaneous catheter aspiration embolectomy was performed in six patients. The remaining two patients underwent surgical thromboembolectomy. A below-knee amputation had to be performed in two patients, thus representing a morbidity of the primary treatment of 25%. MAT of equal value were detected in the ascending (n = 1) and thoracic aorta (n = 3) by means of TEE, CT, or MRI. MAT in the abdominal aorta (n = 4) were identified by means of CT and MRI. Surgical removal of MAT was performed in seven patients by means of graft replacement of the ascending aorta (n = 1), open thrombectomy of the descending aorta (n = 2), and thrombendarterectomy of the abdominal aorta (n = 4), without intraoperative or postoperative complications. No recurrence of MAT occurred during a median follow-up period of 13 months (range, 4 to 24 months). CONCLUSION: MAT represent an important source of arterial thrombembolism. A diagnostic workup of the aorta, preferably by means of CT or MRI, should be performed in all patients in whom other sources of embolization have been ruled out. The ideal therapeutic approach to these patients still awaits prospective evaluation. However, based on our experience, MAT can be successfully treated with a definitive surgical procedure in selected patients, with low mortality and morbidity.

Mural thrombus of the aorta. Ann Vasc Surg. 1988 Jul;2(3):201-4.

Twenty-six peripheral arterial emboli complicating 14 cases of mural thrombi of the aorta were diagnosed between January 1978 and December 1986. None of these patients had any cardiovascular history; their mean age was 49 years. Presenting signs were acute ischemia of the lower limbs in 12 cases and chronic ischemia in two. Arteriograms and CT scan were diagnostic. The mural thrombi were infrarenal in 13 cases and suprarenal in one. Treatment of the thrombus was surgical in all but one patient. In four cases, treatment of the underlying cause was simultaneous with embolectomy; in nine patients, treatment was secondary because further workup was needed. In one case, the patient died following embolectomy before definitive treatment could be undertaken. Results were considered good in 11 cases (unlimited walking distance, no recurrent emboli), and poor in three cases (two major amputations and one death). The incidence of mural thrombi is not known. In our experience, they accounted for 3.8% of nonaneurysmal aortoiliac lesions operated upon during a nine-year period and were responsible for 5% of peripheral arterial emboli. Mural thrombosis of the aorta constitutes a dangerous condition with a potentially lethal final outcome. Recurrent emboli are inevitable without surgical treatment of the source.

Mural thrombus of the aorta: an important, frequently neglected cause of large peripheral emboli. Ann Surg. 1981 Dec;194(6):737-44.

The association between white thrombus in the aorta and multiple embolic occlusions of peripheral vessels was made 22 years ago. However, mural thrombus has been neglected as a major cause of embolus because the process was attributed to paradoxical effects of heparin. Our recent experience indicates it is a more generalized problem. During the past five years, AP and lateral abdominal aortograms demonstrated the presence of large filling defects within the lumen of the aorta in 20 of 39 patients with sudden occlusion of a distal artery. Thirteen patients were not on heparin. These 3.4 X 1-2 cm defects were present anywhere from T-10 to the aortic bifurcation and were suprarenal in ten patients. The 20 patients had a total of 36 separate embolic events, with five patients experiencing seven occlusions of renal or superior mesenteric arteries. Serious medical problems coexisted, and all patients had at least two of five important "risk factors." These were heart disease, recent thrombophlebitis, heparin therapy, abdominal atherosclerosis and postoperative status. Catheter embolectomy alone was associated with recurrent embolization in four of six patients. Three patients died and two required amputation. Of 12 patients treated by embolectomy combined with open aortotomy, recurrent embolization occurred in none, death in one and amputation in two. All patients with visceral artery occlusions survived with normal function of the previously occluded structure. We urge wider application of abdominal angiography in order to treat more appropriately a sizable proportion of patients whose distal emboli originated from large chunks of white thrombus in the abdominal aorta.