Pathophysiologic correlates of thromboembolism in nonvalvular atrial fibrillation: II. Dense spontaneous echocardiographic contrast (The Stroke Prevention in Atrial Fibrillation [SPAF-III] study)

We analyzed transesophageal echocardiograms from 772 participants in the St roke Prevention in Atrial Fibrillation (SPAF-III) study, characterizing spo ntaneous echocardiographic contrast (SEC) in the left atrium or appendage a s faint or dense. The association of dense SEC with stroke risk factors and anatomic, hemodynamic, and hemostatic parameters related to specific throm boembolic mechanisms was evaluated by multivariate analyst. Spontaneous ech ocardiographic contrast was present in 55% of patients and was dense in 13% . Age (odds ratio [OR] 2.4/decade, P < .001), constant atrial fibrillation (OR 6.9, P < .001), history of hypertension (OR 3.2, P < .001), and current tobacco smoking (OR 2.6, P = .04) were independent clinical predictors of dense SEC. Multivariate analysis of clinical, echocardiographic, and hemost atic parameters yielded age as the sole independent clinical predictor of d ense SEC (OR 2.4/decade, P < .001). Other independent predictors were measu res of left atrial/appendage flow dynamics, left atrial size (OR 2.4/cm dia meter, M-mode, P < .001), atherosclerotic aortic plaque (OR 2.8, P = .002), and plasma fibrinogen >350 mg/dL (P < .001). Results were similar when SEC of any density was analyzed. In conclusion, SEC occurred in more than half of these patients with prospectively defined nonvalvular atrial fibrillati on but was usually faint. Dense SEC was strongly associated with previously reported clinical predictors of stroke, linking them to thromboembolism th rough atrial stasis. Diverse pathophysiologic factors including atrial stas is, fibrinogen level, and aortic plaque influence SEC.