Non-Vitamin K Oral Anticoagulants in Stroke Patients: Practical Issues

Significance of imaging The concept of “1-3-6-12 day rule” was recently mentioned as a consensus approach for recommendations for anticoagulation in patients with cerebral ischemic event, either transient ischemic attack or stroke. As mentioned by the authors, the initiation of anticoagulation in these patients depends on various factors. However, the decision to initiate or restart the anticoagulation primarily pivots around the size of infarction delineated by neuroimaging. Recent advent of novel imaging techniques has been critical in the success in stroke community. Risk of cerebral hemorrhagic transformation is majorly related to the size and age of the cerebral infarct. In our clinical practice, we tend to prefer following simplified, yet logical algorithm to approach patients with recent cerebral ischemic event who have a strong indication for anticoagulation (Table 1): A) No infarction or clinically diagnosed transient ischemic attack: anticoagulation could be started immediately. B) Infarct size ≤1.5 cm diameter → anticoagulation could be started in 2 days, C) Infarct size between 1.6 cm-3 cm → anticoagulation to be initiated in 4-5 days, D) Infarct size ≥3 cm: anticoagulation could be started at day 7. Any patients with hemorrhagic conversion or large parenchymal bleeds should be reimaged to confirm the stability of bleed. For cases with mild hemorrhagic infarction (HI-1/2), anticoagulation could be started in 7-10 days, while more severe cerebral hemorrhage including parenchymal hematomas, subdural or subarachnoid hemorrhage require a minimum waiting time of at least 2-4 weeks depending on urgency of anticoagulation in individual cases.