Mural thrombus of the aorta: an important, frequently neglected cause of large peripheral emboli.

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.