Prognostic Implications of Left Atrial Spontaneous Echo Contrast in Nonvalvular Atrial Fibrillation

Objectives: This study examined the influence of left atrial spontaneous echo contrast on the subsequent stroke or embolic event rate and on survival in patients with nonvalvular atrial fibrillation.

Background: Left atrial spontaneous echo contrast is associated with atrial fibrillation and a history of previous stroke or other embolic events. However, the prognostic implications of spontaneous contrast in patients with nonvalvular atrial fibrillation are unknown.

Method: The study group comprised 272 consecutive patients with nonvalvular atrial fibrillation undergoing transesophageal echocardiography. Clinical and echocardiographic data were collected at baseline, and patients were prospectively followed up, and all strokes, other embolic events and deaths were documented. The relation between spontaneous contrast at baseline and subsequent stroke, other embolic events and survival was analyzed.

Results: Left atrial spontaneous echo contrast was detected at baseline in 161 patients (59%). The mean follow-up was 17.5 months. The stroke or other embolic event rate was 12%/year (15 strokes, 3 transient ischemic attacks, 2 peripheral embolisms) in patients with, compared with 3%/year (5 strokes) in patients without, baseline spontaneous contrast (p = 0.002). In 149 patients without previous thromboembolism, the event rate was 9.5%/year in patients with and 2.2%/year in patients without spontaneous contrast (p = 0.003). There were 25 deaths in patients with and 11 deaths in patients without spontaneous contrast. Patients with spontaneous contrast had significantly reduced survival (p = 0.025). On multivariate analysis, spontaneous contrast was the only positive predictor (odds ratio 3.5, p = 0.03) and warfarin therapy on follow-up the only negative predictor (odds ratio 0.23, p = 0.02) of subsequent stroke or other embolic events.

Conclusions: Transesophageal echocardiography can risk stratify patients with nonvalvular atrial fibrillation by identifying left atrial spontaneous echo contrast. These patients have both a significantly higher risk of developing stroke or other embolic events and a reduced survival, and they may represent a subgroup in whom the risk/benefit ratio of anticoagulation may be most favorable.