[Measurement of d-dimers in non-valvular atrial fibrillation. First prospective Tunisian study]

Atrial fibrillation can expose to thrombo-embolic complications. Many biomarkers have been tested to refine the stratification of thrombo-embolic risk. The study aim was to assess the interest of the d-dimer testing in this pathology. We conducted a prospective observational study including 50 cases and 19 controls, enrolled at the cardiology department of the Mongi Slim Hospital, from July to November 2012. The d-dimer assay was performed on mini-VIDAS(®) and analyzed according to clinical, echocardiographic and biological data. The mean age of patients was 61.8±10.6years. The mean CHA2DS2-VASc score was 2.58±1.31. The average of D-dimer levels was 590±506ng/ml in patients and 225.26±112.95ng/ml in controls (P=0.02). No significant difference has been found between the d-dimer level and age, sex, type and etiology of atrial fibrillation, the CHA2DS2-VASc score, the left atrial surface. Among patients on acenocoumarol, d-dimer levels was significantly higher in patients with an INR<2 compared to those with an INR≥2 (P=0.004). We identified a positive d-dimer threshold (300ng/ml) in patients distinguishing them significantly with controls (P<0.001). In conclusion, the measurement of d-dimers could help clinicians to identify patients with atrial fibrillation having an increased coagulability and, therefore, an increased thrombo-embolic risk. It could be complementary to the determination of INR in monitoring anticoagulation therapy: d-dimers level refines the thrombo-embolic risk and INR measurement assesses the level of anticoagulation and the bleeding risk.