Major vessel occlusion may predict subtherapeutic anticoagulation intensity and feasibility of administration of intravenous thrombolytics

OBJECTIVE We investigated the association between the presence of major vessel occlusion (MVO) and the intensity of the International Normalized Ratio (INR) in cardioembolic high-risk patients taking warfarin. We also evaluated whether the presence of MVO could predict the subtherapeutic range of INR ≤1.7 ensuring safe administration of intravenous thrombolytics. METHODS The medical records of 177 cardioembolic stroke patients who were taking warfarin between April, 2008 and March, 2015 were retrospectively analyzed. Logistic regression analysis was performed to calculate the odds ratios (ORs) and 95% confidence intervals (95% CIs) for the association between vessel occlusion and intensity of INR. To predict INR ≤1.7, decision tree analysis was performed. RESULTS INR was inversely associated with MVO in an unadjusted model (OR, 0.36; 95% CI, 0.17-0.76), and in a model adjusted for initial NIHSS score and time from symptom onset to arrival (OR, 0.28; 95% CI, 0.11-0.73). Fifty-two of 58 (89.7%) patients with MVO had an INR ≤1.7, compared with 83 of 119 (69.7%) patients without MVO. Indication for anticoagulation agent use was dichotomized into NVAF and others, and applied to the subgroup of patients with MVO. All patients with NVAF (31/31, 100%) had INR ≤1.7, while 21 of 27 of the other patients (77.8%) had INR ≤1.7. CONCLUSIONS Low INR at presentation in cardioembolic stroke patients during anticoagulation treatment was associated with occurrence of major vessel occlusive stroke. Presence of MVO and indications for anticoagulation may be utilized to ensure the feasibility of administration of intravenous thrombolytics.