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Transesophageal Echocardiography in Atrial Fibrillation.

Because of problems associated with long-term use of anticoagulation therapy, a method of identifying atrial fibrillation (AF) patients at low risk for stroke would be valuable. Transesophageal echocardiography (TEE) can accurately identify left atrial and left atrial appendage thrombi, but its usefulness in managing AF patients remains unclear. Two recent studies provide insights into the potential clinical role of TEE in stratifying stroke risk.

In the first study, 409 Austrian and Slovakian relatively low-risk AF patients not receiving anticoagulation treatment underwent TEE. Only 61 percent of these patients had chronic AF. Ten patients (2.5 percent) had definite left atrial thrombi and 47 (12 percent) had spontaneous echocardiographic contrast. During a mean of 58 months of follow-up, 50 patients (12 percent) had stroke or embolism for a rate of 3 percent per year. Left atrial thrombus was predictive of embolic events (relative risk, 3.9), as was the width of the left atrial appendage; spontaneous echocardiographic contrast was not predictive of risk.

The Stroke Prevention in Atrial Fibrillation study compared low-dose warfarin plus aspirin with standard adjusted-dose warfarin; it was stopped prematurely because adjusted-dose warfarin therapy was markedly superior for stroke prevention. A high-risk subset of 382 patients underwent TEE as part of their initial evaluation. Patients in this subset were women over 75 or individuals of any age with histories of hypertension, embolic events, or impaired LV function. Fourteen percent had left atrial thrombi, and 18 percent had "dense" spontaneous echocardiographic contrast. During the 1.1-year follow-up, 23 embolic events occurred. TEE predictors of events included left atrial thrombus (RR, 2.7), dense spontaneous echocardiographic contrast (RR, 2.6), low left atrial appendage antegrade flow rate (RR, 2.6), and complex atherosclerotic plaque of the descending thoracic aorta (RR, 12.5). Patients who had both left atrial abnormality and complex aortic plaque were at very high risk (21 percent per year), while patients who had neither of these findings were at very low risk (1.3 percent per year), regardless of treatment.

Comment: These studies highlight the role of TEE as a powerful risk-stratifying tool in the management of patients with atrial fibrillation. Patients without left atrial appendage thrombus, spontaneous echocardiographic contrast, or poor antegrade flow, and without complex aortic plaque, represent a very low-risk group for whom anticoagulation therapy is not justified, whereas patients with any one of these findings should be aggressively managed with adjusted-dose warfarin.

— MS Lauer

Published in Journal Watch Cardiology May 22, 1998

Citation(s):

Stollberger C et al. Transesophageal echocardiography to assess embolic risk in patients with atrial fibrillation. Ann Intern Med 1998 Apr 15 128 630-638.

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Stroke Prevention in Atrial Fibrillation Investigators. Transesophageal echocardiographic correlates of thromboembolism in high-risk patients with nonvalvular atrial fibrillation. Ann Intern Med 1998 Apr 15 128 639-647.

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Manning WJ and Douglas PS. Transesophageal echocardiography and atrial fibrillation: Added value or expensive toy?. Ann Intern Med 1998 Apr 15 128 685-687.

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