Efficacy of anticoagulation in resolving left atrial and left atrial appendage thrombi: A transesophageal echocardiographic study

Background Transesophageal echocardiography (TEE) is the gold standard for evaluation of the left atrium and the left atrial appendage (LAA) for the p resence of thrombi. Anticoagulation is conventionally used for patients wit h atrial fibrillation to prevent embolization of atrial thrombi. The mechan ism of benefit and effectiveness of thrombi resolution with anticoagulation is not well defined. Methods and Results We used a TEE database of 9058 consecutive studies perf ormed between January 1996 and November 1998 to identify all patients with thrombi reported in the left atrium and/or LAA. One hundred seventy-four pa tients with thrombi in the left atrial cavity (LAC) and LAA were identified (1.9% of transesophageal studies performed). The incidence of LAA thrombi was 6.6 times higher than LAC thrombi (151 vs 23, respectively). Almost all LAC thrombi were visualized on transthoracic echocardiography (90.5%). Mit ral valve pathology was associated with LAC location of thrombi (P < .0001) , whereas atrial fibrillation or flutter was present in most patients with LAA location of thrombi. Anticoagulation of 47 +/- 18 days was associated w ith thrombus resolution in 80.1% of the patients on follow-up TEE. Further anticoagulation resulted in limited additional benefit. Conclusions LAC thrombi are rare and are usually associated with mitral val ve pathology. Transthoracic echocardiography is effective in identifying th ese thrombi. LAA thrombi occur predominantly in patients with atrial fibril lation or flutter. Short-term anticoagulation achieves a high rate of resol ution of LAA and LAC thrombi but does not obviate the need for follow-up TE E.