D-dimers predict stroke subtype when assessed early.

Background: Early classification of ischemic stroke subtype is important for secondary stroke prevention and may guide further investigations.

Methods: Levels of coagulation activation [fibrinopeptide A (FPA), prothrombin fragment 1+2 (F1+2), thrombin-antithrombin complex (TAT)] and fibrinolysis activation [plasmin-alpha(2)-antiplasmin complex (PAP), D-dimers] markers were measured in 98 consecutive patients with a first-ever acute ischemic stroke admitted within 12 h after symptom onset.

Results: Median age was 67 years and 44% were women. Median time from symptom onset to blood sampling was 4 h. Stroke subtype was classified as 'cardioembolic' (54%), 'large-artery atherosclerosis' (11%), 'small-vessel disease' (5%), 'other determined' (9%) or 'undetermined etiology' (20%). Patients with cardioembolic stroke suffered more often from coronary artery disease than patients with other stroke etiologies (40 vs. 22%, p = 0.019). There were no differences in age, sex, stroke severity, time to blood sampling, frequency of hypertension, diabetes mellitus or current smoking. D-dimers (medians) were higher in patients with cardioembolic strokes than in those with other etiologies (615 vs. 322 microg/l, p < 0.001). No differences in F1+2, FPA, TAT or PAP levels were found. After multivariate analysis, higher D-dimer levels remained independently associated with cardioembolic stroke (p = 0.022). When measured within 6 h, D-dimers below 300 microg/l excluded cardioembolic stroke with a sensitivity of 100% and a specificity of 52%.

Conclusions: Low D-dimer levels in the first few hours make a cardioembolic stroke unlikely, and may be useful to guide further investigations. Other coagulation markers were not useful in differentiating between different stroke etiologies.