Overall, approximately 15%-25% of all strokes in the United States (75,000/year) can be attributed to AF. Known risk factors for stroke in patients with AF include advancing age, female sex, hypertension, diabetes, heart failure, prior history of stroke/transient ischemic attack (TIA)/thromboembolism, coronary artery disease, peripheral arterial disease, and valvular heart disease (rheumatic valvular disease).
One of the major management decisions in AF (and atrial flutter) is determining the risk for stroke and appropriate anticoagulation regimen for low-risk, intermediate-risk, and high-risk patients. For each anticoagulant, the benefit in terms of stroke reduction must be weighed against the risk for clinically significant bleeding. Most clinicians agree that the risk-benefit ratio of anticoagulants in low-risk patients with AF is not advantageous. The appropriate treatment regimen for patients with AF at intermediate risk is controversial. In this population, clinicians should assess risk factors for thromboembolic disease, patient preference, risk for bleeding, risk for falls or trauma, and likelihood of medication adherence.
If warfarin is chosen for anticoagulation, a target international normalized ratio (INR) of 2-3 is traditionally used in this cohort, as this limits the risk for hemorrhage while providing protection against thrombus formation. Warfarin is also superior to clopidogrel or a combination of clopidogrel and aspirin in the prevention of embolic events in higher-risk patients.
Several risk factor assessment algorithms have been developed to aid the clinician on decisions on anticoagulation for patients with AF. The CHADS2 index (Cardiac failure, Hypertension, Age ≥75 years, Diabetes, Stroke or TIA) was widely used previously; however, multiple studies have proven the superiority of the CHA2DS2-Vasc score over the CHADS2 score in predicting the risk for thromboembolism in patients with AF, particularly for participants with low to intermediated CHADS2 scores (0-1).
For more on the management of stroke risk in patients with AF, read here.
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Cite this: Yasmine S. Ali. Fast Five Quiz: Key Aspects of Atrial Fibrillation - Medscape - Sep 13, 2018.