Introduction: Uncertainty exists as to the optimum interval for initiation of oral anticoagulation (OAC) after an acute ischemic stroke (AIS) in patients with atrial fibrillation (AF). Randomized clinical trials of novel oral anticoagulants excluded patients with AIS within 7-14 days. We sought to identify patients at low risk for early initiation of OAC after AIS.
Hypothesis: The benefit of starting OAC within 2 days to prevent recurrent AIS outweighs the risk of hemorrhagic transformation (HT) in select patients.
Methods: Following IRB approval, we completed a retrospective review of patients from the Cleveland Clinic from 2012-2014 with AIS, AF, and at least 1 follow up visit. In addition to demographic and medical history, acute infarct volume on imaging, presence of HT on imaging prior to OAC, timing and type of oral anticoagulation, and ischemic and hemorrhagic complications were noted. Early OAC was defined as starting within 48 hours after stroke onset, and late OAC was thereafter. The two groups were compared using Fisher’s exact test for categorical and Wilcoxon Rank Sum for numeric variables.
Results: One hundred patients (median age 76, interquartile range 66-84) met our study criteria. Thirty-one patients were started on OAC within 2 days vs 53 patients after 2 days (median 1 days vs median 11 days). Compared to patients started on OAC after 2 days, those who initiated OAC within 2 days had significantly lower infarct volume (median 3.35 ml vs median 9.8 ml; p<0.0001), initial NIHSS (median 3 vs median 7; p <0.0001), and fewer people with blood on brain imaging (3% vs 26%; p= 0.0074). Age, prior stroke, and choice of OAC were not significantly associated with timing of OAC. No patients had recurrent AIS or symptomatic HT at median follow-up observation of 37 days. One patient had a non-CNS major hemorrhage after starting OAC. Sixteen patients were not started on OAC for a variety of reasons.
Conclusions: Our results suggest the safety of early initiation of OAC with 2 days in an appropriately selected population of patients with AIS, who have small infarct volumes, mild stroke severity, and lack of HT.