LETTER
Transesophageal Echocardiography in High-Risk Patients with Atrial Fibrillation
Paul A. Tunick, MD, and
Itzhak Kronzon, MD
1 November 1998 | Volume 129 Issue 9 | Page 748
TO THE EDITOR:
The Stroke Prevention in Atrial Fibrillation Investigators Committee on Echocardiography has made an important contribution to our understanding of embolic risk by including the examination of the thoracic aorta in their patients with atrial fibrillation [1]. Aortic atheromas identified by transesophageal echocardiography have been recognized since 1990 as a source of embolism [2]. The Annals study [1] found exactly the same risk for stroke in patients with aortic atheromas (12% in approximately 1 year) as was found in the two previous prospective studies of risk for stroke in these patients [3]. Perhaps the most important finding of the current study is that adjusted-dose warfarin decreased the risk for stroke by 75% in patients with complex aortic plaque. The editorial by Manning and Douglas accompanying the article [4] correctly asks what the mechanism for this action might be. The mobile components of these complex plaques have been found to be thrombi [5], and serial transesophageal studies of the aorta have shown that these thrombi appear and disappear in different locations over time. It is therefore likely that anticoagulation with warfarin prevents thrombus formation (and subsequent embolization) on aortic plaques, just as it does in the left atrium, rather than directly affecting plaque size. Over the long term, plaque size may also be affected by reduction in thrombus formation, although this has not been investigated. It is also interesting to speculate on the mechanism for stroke reduction in the myocardial infarction trials involving the statin drugs. Plaque stabilization in the aorta could also occur with these drugs, as it probably does in the coronary arteries.
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Author and Article Information
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New York University Medical Center; New York, NY 10016
1. Transesophageal echocardiographic correlates of thromboembolism in high-risk patients with nonvalvular atrial fibrillation. The Stroke Prevention in Atrial Fibrillation Investigators Committee on Echocardiography. Ann Intern Med. 1998; 128:639-47.
2. Tunick PA, Kronzon I. Protruding atherosclerotic plaque in the aortic arch of patients with systemic embolization: a new finding seen by transesophageal echocardiography. Am Heart J. 1990; 120:658-60.
3. Atherosclerotic disease of the aortic arch as a risk factor for recurrent ischemic stroke. The French Study of Aortic Plaques in Stroke Group. N Engl J Med. 1996; 334:1216-21.
4. Manning WJ, Douglas PS. Transesophageal echocardiography and atrial fibrillation: added value or expensive toy? [Editorial] Ann Intern Med. 1998; 128:685-7.
5. Kronzon I, Tunick PA. Atheromatous disease of the thoracic aorta: pathologic and clinical implications. Ann Intern Med. 1997; 126:629-37.
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