Background We investigated the association between the reaction time (R), a thromboelastography (TEG) parameter for hypercoagulability, and functional outcomes based on the occurrence of hemorrhagic transformation (HT) and early neurological deterioration (END).

Methods We enrolled ischemic stroke patients and performed TEG immediately after the patients' arrival. The baseline characteristics, occurrence of HT and END, stroke severity, and etiology were compared according to the R. END was defined as an increase of ≥1 point in motor or ≥2 points in the total National Institute of Health Stroke Scale within 3 days after admission. The outcome was the achievement of functional independence (modified Rankin scale [mRS]: 0–2) at 3 months after stroke. Logistic regression analyses were performed to verify the association between R and outcome.

Results HT and END were frequently observed in patients with an R of <5 minutes compared with the group with an R of ≥5 minutes (15 [8.1%] vs. 56 [21.0%], p < 0.001; 16 [8.6%] vs. 65 [24.3%], p = 0.001, respectively). In multivariable analysis, an R of <5 minutes was associated with decreased odds of achieving functional independence (0.58 [0.34–0.97], p = 0.038). This association was maintained when the outcome was changed to disability free (mRS 0–1) and when mRS was analyzed as an ordinal variable.

Conclusion Hypercoagulability on TEG (R <5 minutes) may be a negative predictor for functional outcome of stroke after 3 months, with more frequent HT, END, and different stroke etiologies. This study highlights the potential of TEG parameters as biomarkers for predicting functional outcomes in ischemic stroke patients.