Fragmental or massive embolization in cardiogenic stroke caused by nonvalvular atrial fibrillation

Abstract

Background: After cardioembolic stroke (CES), left atrial thrombus (LAT) is detected by transesophageal echocardiography (TEE) in some cases but not in others. We propose that there are 2 types of embolization in CES: fragmental and massive embolization.

Methods: Consecutive patients with nonvalvular atrial fibrillation (AF) of acute CES or transient ischemic attack (TIA) were prospectively enrolled in the study between May 2009 and July 2011. TEE was performed within 7 days of admission. The patients were classified into 2 groups: those with occlusion of the main trunk (internal carotid artery, M1, and basilar artery; group M) and those with occlusion of other distal arteries (group D). Clinical features were compared between patients who did and did not have a thrombus on TEE.

Results: Of the 41 patients in the study, 21 were in group M and 20 were in group D. Age, sex, and treatment with tissue plasminogen activator did not differ significantly between the 2 groups. The rate of detection of LAT was significantly higher in group D (14% v 65%; P < .001).

Conclusions: Patients with distal artery occlusion had a significantly higher rate of LAT compared to those with main trunk occlusion. Distal artery occlusion in CES therefore tends to result from fragmental embolization and is associated with a remnant LAT, with which there may be a concern of a risk of early recurrence.

Keywords: Atrial fibrillation; stroke; transesophageal echocardiography.