Plasma Measurement of D-Dimer Levels for the Early Diagnosis of Ischemic Stroke Subtypes

Abstract

ONE OF the first objectives in the management of patients presenting with acute ischemic stroke is the diagnosis of the subtype. Advances in the diagnostic evaluations of stroke have helped to identify the most common mechanisms, such as atherosclerosis, cardiac embolism, and lacunae. However, as many as 40% of all ischemic events can remain classified as cryptogenic, because no potential mechanisms are detected or because more than 1 mechanism has been recognized.^1,2 In the early 1990s, a number of clinical studies^3-6 have shown an abnormal hemostatic function in patients with cerebral ischemia. Markers of fibrin formation were found to be significantly increased after acute ischemic stroke^3,4 and transient ischemic attack (TIA)⁵; most of all, their levels significantly differed according to stroke subtype.⁶ When Takano and colleagues⁶ hypothesized that assessment of hematologic variables could provide a useful marker for the early classification of stroke subtypes, none of the coagulation and fibrinolytic variables that were evaluated were available in routine clinical practice. In the past decade, one of these variables, D-dimer, a specific product of degradation of cross-linked fibrin, has gained a wide popularity after the results of a number of studies proved its potential role in the diagnostic approach of venous thromboembolic disorders.⁷ Reference concentrations of plasma D-dimer (usually 8 and several D-dimer assays are now available in many clinical settings for rapid emergency testing. Our study aimed to confirm the results of previous reports and to suggest the potential clinical utility of measurement of plasma D-dimer levels in the early diagnosis of ischemic stroke or TIA subtypes when used as an emergency test in addition to the routine clinical and instrumental assessments.