Key Points
����The absolute risk of stroke varies 20-fold among AF patients according to
age and associated vascular comorbidities. Current AHA guidelines use the
CHADS2 stratification scheme.
����The major risk of antithrombotic medications used to lower the incidence
of AF-related stroke is bleeding.
������ For warfarin, this involves balancing a bleeding risk of 1% to 12% per year.
����The advent of several new antithrombotic agents offers alternatives to
warfarin and may lower the thromboembolic risk threshold for initiating
therapy in patients with AF.
Diagnosis
Table 1. Stroke Risk in Patients With Nonvalvular AF Not
Treated With Anticoagulation According to the
CHADS2 Index
CHADS2 Risk Criteria
Score
Congestive heart failure
Hypertension
Age 75 y
Diabetes mellitus
Prior Stroke or TIA
1
1
1
1
2
Adjusted Stroke Rate (%/y)
Patients (N = 1733)
(95% CI)
CHADS2 Score
120
1.9 (1.2-3.0)
0
463
2.8 (2.0-3.8)
1
523
4.0 (3.1-5.1)
2
337
5.9 (4.6-7.3)
3
220
8.5 (6.3-11.1)
4
65
12.5 (8.2-17.5)
5
5
18.2 (10.5-27.4)
6
