CHADS score

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CHADS score or CHADS2 score is a clinical prediction rule for estimating the risk of stroke in patients with non-rheumatic atrial fibrillation (AF), a common and usually benign heart arrhythmia. It is used to determine the degree of anticoagulation therapy required,<ref name="pmid15477396 ">Template:Cite journal</ref> since AF can cause stasis of blood in the upper heart chambers, leading to the formation of a mural thrombus that can dislodge into the blood flow, reach the brain and cause a stroke. A high CHADS2 score corresponds to a greater risk of stroke, and vice-versa. The CHADS2 score was validated by a study of nonrheumatic atrial fibrillation patients aged 65 to 95 who were not prescribed the anticoagulant warfarin [1].

Details of CHADS score

The CHADS2 scoring table is as follows:

Condition Points
 C   Congestive heart failure 1
 H  Hypertension (or treated hypertension)
 A  Age >75 years
 D  Diabetes
 S2  Prior Stroke or TIA

Adding together the points that correspond to the conditions that a patient has will result in the CHADS2 score. This score is used in the next section to estimate stroke risk.

Risk of stroke

According to the findings of the validation study, the risk of stroke as a percentage per year is:

Annual Stroke Risk<ref name=Gage2001 />
CHADS2 Score   Stroke Risk %       95% CI      

However, warfarin has its own stroke risk and other drawbacks, which were considered in developing the recommendations of the next section [2].

Recommendations for anticoagulation

The following treatment strategies were recommended:<ref name="pmid15477396 " /><ref name=Gage2001 />

Score Risk Anticoagulation Therapy Considerations
0 Low Aspirin Aspirin daily 81-325 mg
1 Moderate Aspirin 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)

Notes & References

[1] Gage BF, Waterman AD, Shannon W, Boechler M, Rich MW, Radford MJ. Validation of clinical classification schemes for predicting stroke: results from the National Registry of Atrial Fibrillation. JAMA 2001;285(22):2864–2870.

[2] Thorsen, Rosand J, Diringer M, Steiner. Intracerebral hemorrhage associated with oral anticoagulant therapy: current practices and unresolved questions. Stroke 2006;37(1):256-262.

Credits & Notices

Authors-contributors to this page (listed alphabetically, last name, first & middle initial only, no institutional affiliations, no scientific titles):

Stawicki SP

Please make sure you look at the existing references before editing to avoid listing the same citation more than once. The order of references is not important as long as the appropriate reference number in the text points to the correct reference number in the references section.

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