D-dimer: a less invasive way to rule out left atrial thrombus

Background Transesophageal echocardiography (TEE) is currently the reference standard for detecting left atrial appendage (LAA) thrombus prior to rhythm control interventions in atrial fibrillation (AF). However, TEE carries a risk of serious complications and is resource-intensive. While D-dimer is a proven marker for thromboembolism, its diagnostic utility for ruling out LAA thrombus, particularly in the era of direct oral anticoagulants (DOACs), has not yet been established. Objective To determine the predictive value of D-dimer as a non-invasive marker for the detection of Left Atrial thrombus in patients with non-valvular AF Methods This prospective diagnostic study enrolled 154 consecutive adult patients with non-valvular AF receiving oral anticoagulants (91.6% DOACs) who were scheduled for rhythm control procedures. Plasma D-dimer was quantified using an automated latex-enhanced immunoassay. All patients underwent TEE with 3D imaging as the reference standard. Diagnostic accuracy was assessed via Receiver Operating Characteristic (ROC) analysis Results LAA thrombus was present in 5.2% (8 out of 154) of the patients. Patients with thrombus had significantly higher median D-dimer levels compared with those without thrombus (741.5 [IQR: 328.5, 1465.8] ng/mL vs. 215.0 [IQR: 215.0, 311.0] ng/mL; p=0.001). ROC analysis identified an optimal cutoff of <227 ng/mL to exclude thrombus, yielding 100% sensitivity (95% CI: 67.6–100%), 100% negative predictive value (95% CI: 95.7–100%), and 58.2% specificity (95% CI, 50.1-65.9%). Integrating D-dimer with the CHA2DS2-VA score increased the AUC from 0.82 to 0.89. No false negatives occurred among the 55.2% (85/154) of patients with D-dimer <227 ng/mL. Conclusions In this anticoagulated non-valvular AF patients, D-dimer <227 ng/mL appears to reliably exclude LAA thrombus with high NPV, potentially sparing the burden of TEE procedures without compromising safety.ROC curve