aspirin in atrial fibrillation
Last reviewed 01/2018
Aspirin treatment may be indicated in patients with paroxysmal or chronic atrial fibrillation.
If risk assessment indicates use of aspirin rather than warfarin then the suggested dose ranges from 75-300mg per day (1)
- the long-term risk of stroke in valvular atrial fibrillation (AF) depends on clinical predictors, which are collectively assessed in the CHADS2 scoring scheme, an acronym for Congestive heart failure,hypertension, Age>75, Diabetes mellitus, and prior Stroke (2):
Anticoagulation based on the CHADS2 score
| Score | Risk | Anticoagulation Therapy | Considerations |
| 0 | Low | Aspirin or no treatment | No antithrombotic therapy (or aspirin) |
| 1 | Moderate | Aspirin or Warfarin | Aspirin daily or raise INR to 2.0-3.0, depending on factors such as patient preference |
| 2 or greater | Moderate or High | Warfarin | Raise INR to 2.0-3.0, unless contraindicated (e.g. clinically significant GI bleeding, inability to obtain regular INR screening) |
To complement the CHADS2 score, by the inclusion of additional 'stroke risk modifier' risk factors, the CHA2DS2-VASc score has been proposed (2)
- these additional 'clinically relevant non-major' stroke risk factors include
age 65-74, female gender and vascular disease
- in the CHA2DS2-VASc score score, 'age 75 and above' also has extra weight,
with 2 points
CHA2DS2-VASc score for stroke risk in atrial fibrillation
| Feature | Score |
| Congestive Heart Failure | 1 |
| Hypertension | 1 |
| Age >75 years | 2 |
| Age between 65 and 74 years | 1 |
| Stroke/TIA/TE | 2 |
| Vascular disease (previous MI, peripheral arterial disease or aortic plaque) | 1 |
| Diabetes mellitus | 1 |
| Female | 1 |
Reference:
- 1) Lip GYH. Thromboprophylaxis for atrial fibrillation. Lancet 1999;353 (9146):983-8.
- 2) Gage BF,Waterman AD, ShannonW, Boechler M, RichMW, Radford MJ. Validation of clinical classification schemes for predicting stroke: results from the National Registry of Atrial Fibrillation. JAMA 2001;285(22):2864-70.
- 2) Lip GY, Nieuwlaat R, Pisters R, Lane DA, Crijns HJ. Refining clinical risk stratification for predicting stroke and thromboembolism in atrial fibrillation using a novel risk factor-based approach: the euro heart survey on atrial fibrillation. Chest. 2010 Feb;137(2):263-72.
antithrombotic treatment in chronic atrial fibrillation
antithrombotic prophylaxis in paroxysmal AF