The D-dimer assay: A possible tool in the evaluation of atrial thrombosis

Abstract

A trial fibrillation (AF) is the most common sustained arrhythmia seen in clinical practice, and affects more than 4% of the population older than 60 years of age (1,2). Peripheral thromboembolism and ischemic stroke contribute significantly to the observed mortality and morbidity rates. AF contributes to 15% to 20% of all strokes (1,3), and emboli arise predominantly from the left atrial appendage (LAA) (4). Hence, there is a need to exclude atrial thrombi before cardioversion in symptomatic AF. A recent large, randomized controlled trial has shown that negative transesophageal echocardiography (TEE) results may obviate the need for prolonged anticoagulation before cardioversion, with no significant difference in embolic events compared with conventional therapy (5). Because of the complex multilobed configuration of the LAA and the minute size of clinically significant thrombi, there are inherent limitations in using a nontomographic technique for visualization of the LAA. Using the two-dimensional beam of TEE in visualizing the three-dimensional anatomy of the LAA is analogous to using a searchlight to visualize the entire roof of a cave, which is technically difficult to achieve completely. Studies have shown that embolism may presumably occur after cardioversion of AF, despite apparent exclusion of a pre-existing atrial thrombus by TEE (6). Plasma D-dimer constitutes an antigen-antibody reaction to the dimeric final degradation product of a mature clot. An elevated fibrin D-dimer has a high sensitivity for intravascular thrombus (7) and may improve the evaluation of a patient with AF before cardioversion. CASE PRESENTATIONA 56-year-old man eight years post-renal transplant and four years post-coronary artery bypass surgery, as well as a history of adequately treated, methicillin-resistant Staphylococcus epidermidis bacteremia, CASE REPORT ©2008 Pulsus Group Inc. All rights reserved Atrial fibrillation (AF) is a common arrhythmia seen in clinical practice, and affects more than 4% of the population older than 60 years of age. Peripheral thromboembolism contributes significantly to the observed morbidity and mortality. Symptomatic AF, before cardioversion to normal sinus rhythm, requires either exclusion of atrial thrombi using transesophageal echocardiography (TEE) or the conventional use of three weeks of adequate anticoagulation. The exclusion of atrial thrombi by TEE, a nontomographic technique but comparable with conventional treatment of AF in outcomes, has inherent limitations due to the complex three-dimensional multilobed anatomy of the left atrial appendage, where the majority of atrial thrombi arise. Also, the conventional treatment of three weeks of therapeutic anticoagulation before cardioversion reportedly does not always eliminate atrial thrombi. Plasma D-dimer constitutes an antigen-antibody reaction to the dimeric final degradation product of a mature clot. An elevated fibrin D-dimer has a high sensitivity for intravascular thrombosis and, hence, may improve the evaluation of a patient with A...

The association of high D-dimer level with high risk of ischemic stroke in nonvalvular atrial fibrillation patients

“…Over the last 2 decades, numerous studies have explored the predictive value of D-dimer levels in thromboembolic and cardiovascular events with AF. [ 2 , 27 – 29 ] Some studies [ 30 , 31 ] found that D-dimer can be used as a possible test to exclude left atrial thrombus. Transesophageal echocardiography (TEE) is the gold standard for left atrial thrombus.…”

D-dimers Are a Predictor of Clot Volume Inside Membrane Oxygenators During Extracorporeal Membrane Oxygenation

“…The D‐dimer levels decreased significantly within 2 days after MO exchange. The slow decrease is explained by the half‐life of the D‐dimers of approximately 48 h . In time, exchange of the MO reduced risks of system‐induced coagulation disorder such as bleeding diathesis.…”

D-Dimer assay as a non invasive test for the diagnosis of left atrial Thrombi in Indian patients with Rheumatic MS

“…Habara et al 16 measured D-dimer level in 925 patients with nonvalvular atrial fibrillation undergoing TEE, which detected 83 LAA thrombus and yielded a negative predictive value of 97% for identifying LAA thrombus for a cut-off value of D-dimer. D-dimer levels have been shown to be increased in AF especially in patients having multiple risk factors for embolism in earlier studies 17,18 . Ibebuogu et al 18 described a case where elevated D-dimer resulted in performance of TEE, which documented atrial thrombus in a patient with infective endocarditis, atrial fibrillation and pulmonary edema and saved the patient from complications of cardioversion, which should have resulted from emergency cardioversion.…”