LAUSR

To the Editor: Meinel and colleagues reported the effect of prior anticoagulation with vitamin K antagonists or direct oral anticoagulants (DOACs) on subsequent stroke severity, utilization of intravenous thrombolysis (IVT), safety of IVT, and 3-month outcomes in patients with ischemic stroke and atrial fibrillation (AF). Prior DOAC therapy was significantly associated with decreased admission stroke severity and a lower rate of IVT. In addition, the adjusted odds ratio (OR; 95% confidence interval [CI]) of DOAC pretreatment for a favorable 3-month outcome was 1.24 (95% CI = 1.01-1.51). I have some concerns on their study. First, Jung and colleagues conducted a prospective study to investigate the preceding antithrombotic medication use in patients with AF with acute ischemic stroke and its association with initial stroke severity and in-hospital outcomes. The OR (95% CI) of antiplatelet and anticoagulant users for a mild initial neurological deficit were 1.23 (95% CI = 1.09–1.38) and 1.31 (95% CI = 1.15–1.50), respectively. As a large portion of patients with AF still did not receive antithrombotic medication before an ischemic stroke event, they recommended prehospitalization use of antithrombotic medication to keep a mild initial neurological deficit and favorable outcome at discharge. I think that subanalysis by classifying anticoagulants into vitamin K antagonists and DOACs might lead to the advantage of DOACs for keeping safety and effectiveness on clinical outcomes. Second, Freixa-Pamias and colleagues conducted a retrospective study to evaluate the association of AF-related ischemic stroke with the prescription patterns of antithrombotic treatment. The adjusted OR (95% CI) of patients with antiplatelet versus control medications with vitamin K antagonists or DOACs for ischemic stroke was 1.89 (95% CI = 1.52–2.37), and risk reduction for ischemic stroke by vitamin K antagonists or DOACs treatment was remarkable. To specify the superiority between vitamin K antagonists and DOACs, an intervention study is recommended. Finally, Kimura and colleagues conducted a prospective study to evaluate safety and effectiveness of oral anticoagulants (OACs) for preventing secondary ischemic stroke in patients with ischemic stroke and AF. As the risk of acute recurrence of ischemic stroke was high in patients with AF, they recommended OAC treatment as early as possible. The OACs include vitamin K antagonists and DOACs. Chan and colleagues conducted a meta-analysis and DOACs had greater effectiveness and safety compared to vitamin K antagonists for stroke prevention in patients with AF. Regarding safety, Kattoor and colleagues reported that the risk of gastrointestinal bleeding and stroke was similar between vitamin K antagonist and DOAC users, and there was a trend toward lower intracranial hemorrhage in the DOAC users. In any case, standard treatment protocol by DOACs should be presented by considering comorbidity and hemorrhagic risk in each individual.