The goal of this paper is to review literature on the topic of anticoagulation resumption after stroke from atrial fibrillation. Following ischemic stroke, the average annual risk of recurrent stroke in a patient with a CHADS2 score of 9 is 12.2%%, translating to an average daily risk of 0.03%%. Oral anticoagulant therapy provides a 75% relative risk reduction. However, in the 2-week period immediately following an acute stroke, this daily risk appears to be elevated. The same period is associated with an increased risk of hemorrhagic transformation of ischemic stroke due to reperfusion, impaired autoregulation, and disruption of the blood-brain barrier. Use of thrombolytics and anticoagulants, baseline infarct size, presence of microhemorrhages, and evidence of hemorrhagic transformation further increases the risk of symptomatic hemorrhagic. The decision to resume anticoagulation early after ischemic stroke from atrial fibrillation must carefully balance the risks of hemorrhagic transformation with the risk of recurrent stroke. There are currently 4 trials in progress at present (OPTIMAS, ELAN, TIMING, and START) comparing different anticoagulant resumption protocols after stroke in patients on non-vitamin K oral anticoagulants. There are a number of major limitations of the studies to date on the timing of anticoagulation resumption on stroke in atrial fibrillation. For instance, they do not explicitly account for infarct size, presence/absence of hemorrhagic transformation, recanalization via mechanical thrombectomy, and bleeding diatheses such as liver synthetic dysfunction or thrombocytopenia. These factors are crucial in personalizing a treatment decision to an individual patient.
Keywords: Atrial fibrillation; Cardioembolism; Cerebral microhemorrhages; Hemorrhagic transformation; Non–vitamin K oral anticoagulants.