Predicting stroke in patients without atrial fibrillation

Background: Only few studies in selected cohorts have examined whether the CHA ₂DS ₂-VASc score can predict the risk of atrial fibrillation and thromboembolic events in patients without atrial fibrillation. Materials and methods: Patients with coronary angiography performed between 2004 and 2012 were grouped according to CHA ₂DS ₂-VASc score. We excluded patients with atrial fibrillation, anticoagulant therapy and follow-up <30 days. The endpoints were atrial fibrillation and a composite of ischaemic stroke, transient ischaemic attack and systemic embolism. Event rates per 100 person-years were estimated for each CHA ₂DS ₂-VASc score (0, 1, 2, 3, 4, and >4). Incidence rate ratios were calculated using low-risk patients (CHA ₂DS ₂-VASc score 0 in males or 1 in females) as reference. Results: In total, 78 233 patients were included with group sizes varying between 8299 (CHA ₂DS ₂-VASc >4) and 19 882 (CHA ₂DS ₂-VASc 2). An increasing CHA ₂DS ₂-VASc score was significantly associated with a future diagnosis of atrial fibrillation (P for trend <0.0001) and an incremental risk of ischaemic stroke, transient ischaemic attack, systemic embolism (P for trend <0.0001) and all-cause death (P for trend <0.0001). Patients with a CHA ₂DS ₂-VASc score of 3 had a rate of ischaemic stroke/transient ischaemic attack/systemic embolism of 1.30 per 100 person-years. Conclusions: Among patients undergoing coronary angiography, the CHA ₂DS ₂-VASc score predicted a future diagnosis of atrial fibrillation and the composite risk of ischaemic stroke, transient ischaemic attack or systemic embolism in patients without atrial fibrillation. A CHA ₂DS ₂-VASc score of 3 was associated with a risk that would justify prophylactic oral anticoagulation treatment in a patient with atrial fibrillation.