The utility of quantitative D-Dimer assay as a biomarker in the diagnosis and exclusion of Cerebral Venous Sinus Thrombosis

Thrombotic disorders are characterized by the presence of elevated levels of detectable fibrin degradation products in the blood. The utility and sensitivity of quantitative D-Dimer assay to rule out the diagnosis of deep vein thrombosis is well established. We extrapolated this principle to evaluate the utility of D-Dimer assay in exclusion of cerebral venous sinus thrombosis (CVST). CVST is an important cause of cerebrovascular accidents in young patients and the residual neurological deficits can be minimized if correct therapy, i.e., anticoagulation is instituted in a timely manner. As advanced imaging modalities that are required for the diagnosis of CVST might not be readily available everywhere, it is important to have a sensitive biomarker which can guide clinicians to rule out the diagnosis with a reasonable confidence. We evaluated the patients admitted at a tertiary care center who underwent Computed tomography (CT) Venography/Magnetic resonance (MR) Venography of the brain with the clinical suspicion of CVST. After appropriate exclusion, a quantitative D-Dimer assay was performed in patients who had CVST on CT/MR Venography and was compared with those patients who did not. Receiver operating characteristic (ROC) analysis revealed that quantitative D Dimer had poor diagnostic accuracy for the differentiation of CVST from non CVST cases (Area under the curve = 0.694), but D-Dimer levels of <300 ng/mL had a sensitivity of 90% for ruling out the diagnosis of CVST.