Aspirin Should Not Be Started for Atrial Flutter with CHA₂DS₂-VASc Score of 0
For patients with atrial flutter and a CHA₂DS₂-VASc score of 0, no antithrombotic therapy (including aspirin) is recommended, as these patients have a truly low stroke risk that does not justify the bleeding risk associated with aspirin. 1, 2
Guideline Recommendations for Atrial Flutter
Atrial flutter receives identical antithrombotic management as atrial fibrillation according to the 2014 AHA/ACC/HRS guidelines, meaning all stroke prevention recommendations for AF apply equally to atrial flutter. 1
For patients with nonvalvular atrial fibrillation/flutter and a CHA₂DS₂-VASc score of 0, it is reasonable (Class IIa recommendation, Level of Evidence B) to omit all antithrombotic therapy, including aspirin. 1
Understanding CHA₂DS₂-VASc Score of 0
A true score of 0 means a male patient with no risk factors (no heart failure, hypertension, diabetes, vascular disease, age <65 years, and no prior stroke/TIA). 2, 3
For female patients, a score of 1 (from sex alone) is functionally equivalent to a male score of 0 and represents truly low risk—contemporary guidelines differentiate by recommending anticoagulation only when women have ≥2 points (meaning at least one additional clinical risk factor beyond sex). 1, 2
The annual stroke rate for untreated patients with CHA₂DS₂-VASc score of 0 is approximately 0.47-0.49% per year, which is genuinely low. 4
Why Aspirin Is Not Recommended
Aspirin provides minimal stroke prevention benefit in atrial fibrillation/flutter while carrying a bleeding risk similar to oral anticoagulation, especially in elderly patients. 5, 6
The 2010 ESC guidelines explicitly state that for patients with no risk factors (CHA₂DS₂-VASc score 0), no antithrombotic therapy is preferred over aspirin. 1
Research demonstrates that in low-risk AF ablation patients (CHA₂DS₂-VASc 0-2), aspirin therapy does not lower stroke risk but significantly increases bleeding complications compared to no therapy. 7
A real-world cohort study of AF patients with CHA₂DS₂-VASc score 0 found that aspirin or anticoagulation provided no benefit over no treatment for stroke prevention, survival, or net clinical benefit. 8
Clinical Decision Algorithm
Calculate the CHA₂DS₂-VASc score for the patient with atrial flutter (same as for AF). 1, 2
If score = 0 (males) or 1 from sex alone (females): Recommend no antithrombotic therapy—neither aspirin nor anticoagulation. 1, 2, 3
If score ≥1 (males with ≥1 clinical risk factor) or ≥2 (females with ≥1 additional risk factor beyond sex): Consider oral anticoagulation (preferably DOACs over warfarin), not aspirin. 1, 3
Reassess the CHA₂DS₂-VASc score periodically as patients age or develop new risk factors. 1
Important Caveats
The 2014 North American guidelines create potential confusion by stating that patients with CHA₂DS₂-VASc score of 1 "may be considered" for aspirin, anticoagulation, or no therapy (Class IIb). 1 However, this recommendation does not distinguish sex from other clinical risk factors, which is problematic since female sex alone (score 1) does not warrant treatment. 1, 2
Aspirin monotherapy should not be considered an effective stroke prevention strategy in AF/flutter patients, as European guidelines explicitly recommend against it regardless of stroke risk. 1, 5
The bleeding risk with aspirin (1.08% per year in untreated low-risk patients) approaches the stroke risk itself (0.49% per year), making the risk-benefit ratio unfavorable. 4
If the patient develops even one additional stroke risk factor (increasing score to 1 in males or 2 in females), the stroke rate increases 3-fold and mortality increases 3.12-fold, at which point oral anticoagulation becomes appropriate—not aspirin. 4