Aims: We investigated baseline characteristics, antithrombotic use, and clinical outcomes of patients with atrial fibrillation (AF) and a thrombo-embolic event in the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) study to better inform the care of these high-risk patients.
Method and results: Thrombo-embolic events were defined as stroke (ischaemic or unknown cause) or systemic embolism (SE). Clinical outcomes were estimated using the Kaplan-Meier method. All-cause mortality and International Society on Thrombosis and Haemostasis (ISTH) major bleeding after events were analysed using a Cox proportional hazards model with time-dependent covariates. Of 18 201 patients in ARISTOTLE, 365 experienced a thrombo-embolic event [337 strokes (ischaemic or unknown cause), 28 SE]; 46 (12.6%) of which were fatal. In the 30 days before and after a thrombo-embolic event, 11% and 37% of patients, respectively, were not taking an oral anticoagulant. During follow-up (median 1.8 years), 22 patients (7.1%/year) had a recurrent stroke, 97 (30.1%/year) died, and 10 (6.7%/year) had major bleeding. Compared with patients without a thrombo-embolic event, the short- and long-term adjusted hazards of death in patients with a thrombo-embolic event were high [≤30 days: hazard ratio (HR) 54.3%, 95% confidence interval (95% CI) 41.4-71.3; >30 days: HR 3.5, 95% CI 2.5-4.8; both P < 0.001]. The adjusted hazards of major bleeding were also high short-term (HR 10.37, 95% CI 3.87-27.78; P < 0.001) but not long-term (HR 1.7, 95% CI: 0.77-3.88; P = 0.18).
Conclusions: Thrombo-embolic events were rare but associated with high short- and long-term morbidity and mortality. Substantial numbers of patients are not receiving oral anticoagulattherapy before and, despite this risk, after a first thrombo-embolic event.
Clinical trial registration: ClinicalTrials.gov (NCT00412984).