The current risk stratification for stroke most widely used is CHADS2. This system uses common clinical conditions to assess risk for stroke. Points are assigned, and anticoagulation is given depending on how many points the patient has:
|C||Congestive heart failure||1|
|H||Hypertension: blood pressure consistently above 140/90 mmHg (or treated hypertension on medication)||1|
|A||Age ?75 years||1|
|S2||Prior Stroke or TIA||2|
This system is simple, easy to apply and used clinically. The current (5/2011) recommendations are:
0 Low risk Aspirin
1 Moderate Risk Anticoagulation (Coumadin, Pradaxa) or ASA
2 or < High Risk Anticoagulation (Coumadin, Pradaxa)
All of these strategies need adjustment for risk of serious bleeding.
There is a newer system available, the CHA2DS2-VASc score [Congestive heart failure, Hypertension, Age ?75 years (doubled), Diabetes mellitus, Stroke (doubled), Vascular disease, Age 65–74 years, Sex category] which does make it more risky to have peripheral vascular disease, be female, or be older than 75, which may refine risk.
However, the main point is that clinical factors predict risk, and those factors are what are used to determine who should get aggresive anticoagulation.