Understanding the Risk Factors of Stroke with AFib
It has long been known that having a condition known as atrial fibrillation or AFib, a specific type of heart arrhythmia, has been shown to increase the risk of stroke. Atrial fibrillation prevents the upper chambers of the heart from beating normally, which allows blood to stagnant, increasing the risk of clotting and thus increasing the risk of stroke.
Because of this phenomenon, patients with AFib are often prescribed blood thinners such as Coumadin to prevent the possibility of clot formation. Blood thinners are challenging drugs, not only to prescribe, but to maintain. Patients are required to have regular testing done to ensure anticoagulant medications are present in the proper dosages and must take care to try and prevent injury as excessive bleeding may occur. Because of the complexities involved with administering and maintaining proper blood thinner levels, doctors use a scoring system to determine which AFib patients need anticoagulant therapy and which ones don't. This scoring system is known as the CHADS scoring system.
What is a CHADS score?
CHADS is an acronym used to describe the risk factors for experiencing a stroke in people who have AFib. Each risk factor is assigned a point value and the cumulative point value determines whether the patient needs blood thinner therapy or can be maintained with aspirin only.
The CHADS2 scoring system determines stroke risk:
CHADS Risk Criteria Score
C Congestive heart failure: 1
H Hypertension — high blood pressure: 1
A Age≥75: 1
D Diabetes mellitus: 1
S Stroke or TIA (transient ischemic attack, called a mini-stroke): 2
Atrial Fibrillation Treatment Guidelines
After assessing a patient's risk factors and totaling up his or her CHADS score, doctors will recommend a therapy that controls stroke risk:
Score Risk Recommendation
0 Low Aspirin (81–325 mg) daily
1 Intermediate Aspirin (81–325 mg) daily or warfarin
2 or more High Warfarin
The CHADS scoring system allows doctors to quickly identify those patients with AFib who would benefit from anticoagulant therapy versus those who can be maintained with aspirin therapy or generally don't require treatment at all. A person with none of the CHADS2 risk factors would have a result of 0, which equals a low risk. In most cases, doctors would not prescribe anticoagulant therapy, opting instead for an aspirin regimen instead. Patients who score 2 or more are generally considered high risk and are often prescribed a blood thinner to reduce the risk of stroke. Those with a score of one represent an intermediate risk and therefore have more options as to whether or not anticoagulant therapy should be undertaken.