RESUMO
Patients with atrial fibrillation/atrial flutter (AF) are notoriously predisposed to thromboembolic events secondary to the development of thrombi within the left atrium of the heart. AF accompanied by a fairly decent CHA2DS2-VASc score is a known indication for full anticoagulation, frequently with direct oral anticoagulants (DOACs), such as apixaban. Following extensive studies weighing the benefits of anticoagulation versus risks of major bleeding, patients meeting two or more of the dose-reduction criteria (age ≥80 years, weight ≤60 kg, and/or creatinine ≥ 1.5 mg/dL) require appropriate step-down to a reduced dose of apixaban. However, with rising concern for bleeding complications, many physicians are found to have been reducing the dose of apixaban despite the patient not completely meeting the defined criteria. Our study particularly emphasizes the risk of significantly increased thromboembolic complications in the setting of sub-therapeutic anticoagulation, in patients with both appropriately and inappropriately reduced doses of apixaban.