Abstract 97: Acute Ischemic Stroke Despite Anticoagulant Use: The Neuro-AFib Study

Abstract

Background: Acute ischemic stroke (AIS) admissions in patients with atrial fibrillation (AF) using anticoagulants (AIS-despite-AC) are commonly seen in stroke units but data on their frequency, causes, and outcomes are scarce. Methods: The Neuro-AFib study is a multicenter effort geared toward elucidating the causes and consequences of strokes in a contemporary AF cohort. Detailed clinical, laboratory and multimodal imaging data from known AF patients consecutively admitted to 20 stroke centers with an IS between 1/2018-12/2019 were used to define characteristics of AIS-despite-AC and compared to AIS-off-AC. Results: Out of 4456 patients with known AF prior to the AIS, 2051 (46%) were using anticoagulants. Patients who had AIS-despite-AC were younger (76.8 + 11 vs 77.8 + 12, p=0.007), had higher mean CHA 2 DS 2 -VASc scores (4.57 + 1.7 vs 4.21 + 1.7, p<0.001), and they were more likely to have permanent AF (23.5% vs 19.6%, p=0.002) and a past-history of stroke/TIA (36% vs 25%, p<0.001) when compared to non-AC group. Chronic embolic (non-lacunar) infarcts on imaging were more common among AIS-despite-AC (34.5% vs 26.7%, p<0.001). Acute large vessel occlusion (LVO) was common among AIS-despite-AC (48%). The pattern of the acute infarcts (numbers, embolic features) was not different. The calculated acute infarct volume was large (34ml) and mean NIHSS was 10.4 for AIS-despite-AC. Intravenous thrombolysis was used much less commonly for AIS-despite-AC (10.5% vs 32.1%, p<0.001). Symptomatic carotid disease was suspected in 2.4%, a hypercoagulable condition in 5.7%, whereas acute lacunar infarct was found in 6.5% of all patients. Death or significant disability (mRS 3-5) at hospital discharge were common in AIS on vs off AC (70.6% vs 75.2%, p<0.001). Conclusions: Based on a large multicenter cohort, AF patients who have AIS-despite-AC have higher AF load and risk scores, most don't have a concurrent etiology and they are more likely to have recurrent embolic events. The stroke severity, common presence of LVO, infarct size, and poor outcomes are alarming features, and most patients are unable to receive thrombolysis because of AC use. Overall, detection of AF patients at risk of AIS-despite-AC and development of specific preventive modalities should be priorities.