Effect of low-intensity warfarin therapy on left atrial thrombus resolution in patients with nonvalvular atrial fibrillation - A transesophageal echocardiographic study

The presence of left atrial thrombus (LAT) is associated with an increased risk of embolic stroke. However, it has yet to be established definitively whether low-intensity warfarin therapy (INR: 1.5-2.0) can prevent LAT forma tion in patients with nonvalvular atrial fibrillation (NVAF). The present s tudy analyzed the clinical and transesophageal echocardiography (TEE) featu res of 123 such patients to identify risk factors for LAT formation and the efficacy of prophylactic low-intensity warfarin therapy. Left atrial throm bi were found in 35 patients (28%) in whom systemic hypertension (49% vs 23 %; p<0.01) and ischemic heart disease (17% vs 3%; p<0.01) were more frequen t. Left ventricular ejection fraction (54 +/- 14% vs 60 +/- 11%; p<0.05), l eft ventricular end-diastolic dimension (51<plus/minus>7 mm vs 48 +/-5 mm; p<0.05), spontaneous echo contrast (2.2<plus/minus>0.7 vs 1.4 +/-0.9; p<0.0 1), left atrial diameter (50<plus/minus>6 mm vs 43 +/-7 mm; p<0.01), left a trial appendage blood velocity (22.3<plus/minus>8.7 cm/s vs 37.2 +/- 21.5 c m/s; p<0.01) and the incidence of left ventricular. hypertrophy (37% vs 15% ; p<0.01) were also significantly different between the groups. Fourteen pa tients received continuous warfarin therapy (target INR: 1.5-2.0) and on th e follow-up TEE study the left atrial thrombus resolved in 10 (71%). There were no thromboembolic events or major hemorrhagic complications in these p atients, so it was concluded that low-intensity warfarin therapy is efficac ious in treating LAT formation in patients with NVAF.