| Overview of Nonvalvular atrial
fibrillation (AF) |
| Prevalence |
 | 1.8 million people in US has AF |
| 16% of patients with ischemic stroke has AF |
| AF is present in over 1/3 of individual over 75 yo, may be less in
African American & Hispanics |
| 1/3 of patients with AF are unaware of condition |
|
| Stroke risk |
| Patients with AF is about 5% / yr. (see
table below) |
| higher risk in the presence of
 | hypertension |
| prior stroke/TIA, |
| left ventricular systolic dysfunction |
| even higher if multiple risk factors |
|
| AF with rheumatic valvular heart disease: 18 fold increase |
| AF without valvular heart disease: 5 fold increase |
|
Stroke risk
prevention |
| Adjusted dose Warfarin with INR 2-3: reduces risk by 70%
|
| Aspirin reduces risk by 20% |
|
Recom-
mendation |
| Treat with Warfarin with goal INR of 2.5 (2.0-3.0) if
| Patient has AF |
| < 75 yo |
| high risk for stroke |
| deemed safe candidate |
|
| For those over 75 years
| Goal INR of 2.0(1.6-2.5) may be acceptable, but efficacy not established
or |
| Goal INR of 2.5 (2.0-3.0) |
|
| For those unable to receive Warfarin, or has low risk of stroke: treat
with ASA 325 mg/day |
|
| Adapted from Practice Parameter. Neurology
1998;51:671-673 |
Risk of stroke for
patients with
nonvalvular atrial fibrillation |
| High risk |
Moderate risk |
Low risk |
| AFI/ACCP consensus criteria |
| history of hypertension |
| diabetes |
| prior stroke or TIA |
| coronary artery disease |
| congestive heart failure |
|
| Age > 65 |
| no high risk factor |
|
| Age < 65 |
| no high risk factor |
|
| Stroke risk, with no therapy |
| about 6 % / yr |
about 2% / yr
(about 3% / yr if over 80 years) |
about 1% / yr |
| SPAF III Study criteria |
| Systolic BP > 160 |
| left ventricular dysfunction |
| prior stroke or TIA |
| Women > 75 yo |
|
| History of hypertension |
| no high risk feature |
|
| no history of hypertension |
| no high risk feature |
|
| Stroke risk with aspirin |
about 8% / yr
(without prior stroke or TIA: 6%/yr)
(with prior stroke/TIA: 12%/yr) |
about 3.5% / yr |
about 1% / yr |
| Adapted from Practice Parameter. Neurology
1998;51:671-673 |
| Danger of Warfarin treatment |
| Risk of intracranial hemorrhage (pooled analysis)
0.3% vs 0.1% per year in control group |
| Risk of intracranial hemorrhage for patient >75 year old
| 1.8% per year |
| Risk of hemorrhage may increase with INR > 3 |
|
| Review of anticoagulant treatment |
|
