From the Guidelines
Atrial fibrillation can cause stroke, increasing the risk by about five times compared to people without this condition. This happens because when the heart's upper chambers (atria) beat irregularly, blood can pool and form clots, which may travel to the brain and cause a stroke 1. The annual rate of stroke in adults with atrial fibrillation ranges from 1 to 20 percent, depending on comorbidities and the patient’s history of cerebrovascular events 1.
Stroke Risk Assessment
To assess stroke risk, doctors typically use the CHA₂DS₂-VASc score, which considers factors like:
- Heart failure
- Hypertension
- Age
- Diabetes
- Previous stroke
- Vascular disease
- Gender This score helps determine if anticoagulation is needed to reduce the risk of stroke 1.
Anticoagulation Therapy
People with atrial fibrillation often need blood thinners (anticoagulants) like warfarin, apixaban (Eliquis), rivaroxaban (Xarelto), dabigatran (Pradaxa), or edoxaban (Savaysa) to reduce this risk 1. The specific medication and dosage depend on individual factors like age, kidney function, and other medical conditions.
Silent Atrial Fibrillation
Even with no symptoms, atrial fibrillation requires medical attention since silent atrial fibrillation carries the same stroke risk as symptomatic cases 1. The selection of an anticoagulant agent should be based on shared decision-making that takes into account risk factors, cost, tolerability, patient preference, potential for drug interactions, and other clinical characteristics 1.
Key Considerations
Some key considerations in managing atrial fibrillation include:
- The risk of bleeding associated with antithrombotics like warfarin 1
- The importance of stratifying and identifying patients at increased risk of stroke 1
- The need for frequent monitoring and dose adjustment to achieve the optimum anticoagulant effect 1
From the Research
Atrial Fibrillation and Stroke
- Atrial fibrillation is a significant risk factor for stroke, with patients having a 5-fold increased risk of stroke relative to those without atrial fibrillation 2.
- The association between atrial fibrillation and stroke is firmly established, and anticoagulation reduces stroke risk in patients with atrial fibrillation 3.
- Ischemic strokes related to atrial fibrillation are highly prevalent, presenting with severe neurologic syndromes and associated with high risk of recurrence 4.
Mechanism of Stroke in Atrial Fibrillation
- The traditional conceptual model of the mechanistic link between atrial fibrillation and cardioembolic infarction is likely oversimplified 2.
- Long-term cardiac rhythm recording studies indicate an inconsistent temporal relationship between atrial fibrillation and infarction, suggesting that cardioembolic stroke in patients with atrial fibrillation may result from the underlying atrial cardiopathy, rather than the rhythm disturbance leading to atrial stasis and thromboembolism 2.
- Atrial cardiopathy is associated with subclinical atrial fibrillation, and research examining anticoagulation after embolic stroke of undetermined source (ESUS) in this population is underway 3.
Prevention and Treatment
- Non-vitamin K antagonist oral anticoagulants have been proven to be safer and equally effective compared with warfarin in stroke prevention for patients with nonvalvular atrial fibrillation 4.
- Rivaroxaban, a novel anticoagulant, exhibits good pharmacokinetic and pharmacoeconomic properties and is an attractive alternative to vitamin K antagonists for the prevention of thromboembolic complications in atrial fibrillation 5.
- Ongoing trials are assessing the optimal timing of non-vitamin K antagonist oral anticoagulant initiation after a recent ischemic stroke and the benefit:harm ratio of non-vitamin K antagonist oral anticoagulant treatment in patients with atrial fibrillation and history of previous intracranial bleeding 4.