Evidence-Based Case Report: The Use of D-Dimer Assay to Exclude Left Atrial Thrombus in Patient with Atrial Fibrillation >48 Hours.

INTRODUCTION: Patients with atrial fibrillation (AF) for >48 hours who are a candidate for cardioversion should have transesophageal echocardiography (TEE) performed to exclude left atrial thrombus (LAT) that may cause systemic thromboembolism upon conversion to sinus rhythm. However, TEE facilities were limited, especially in developing countries. CASE ILLUSTRATION: A 50 years-old man presented with exertional dyspnea and palpitation for 72 hours prior to admission. Electrocardiography showed AF with a ventricular rate of 140x/minute. Cardioversion was decided to be the best approach. This patient has an AF >48 hours of onset, hence, LAT should be excluded by the use of TEE. Unfortunately, there was no TEE facility nearby. DISCUSSION: Upon comprehensive search on the use of D-Dimer assay to exclude the LAT in AF patients, we found seven studies showed increased D-dimer level in those with left atrial thrombus. In 4 studies, AUC was > 0.70, sensitivity and specificity varied from 75.9% to 89% and 73.1% to 95% respectively. However, there is no single cut-off point, due to the heterogeneity of cut-off points.
CONCLUSION: D-dimer assay combined with other variables of atrial thrombus exclusion score is valuable in excluding LAT. Previously, weeks of anticoagulation is more advisable before attempting cardioversion in the absence of nearby TEE facilities. With current evidence, a low D-dimer and ATE score of 0 is safe for cardioversion.