Table 1 Summary of the main stroke risk stratification schemes for patients with atrial fibrillation.
| Risk stratification scheme | Risk strata | |||
|---|---|---|---|---|
| High | Intermediate | Low | ||
| AFI (1994)w22 | High to intermediate risk: aged ⩾65 years; history of hypertension, CAD, or diabetes mellitus | Aged <65 years; no high risk features | ||
| SPAF (1995)w23 | Women aged >75 years; SBP >160 mm Hg; LV dysfunction (on echocardiography or clinically) | History of hypertension; no high risk features | No history of hypertension; no high risk features | |
| Lip (1999)w24 | All patients with previous TIA or cerebrovascular accident; all patients aged ⩾75 with diabetes or hypertension; all patients with clinical evidence of valve disease, heart failure, thyroid disease, and impaired LV function on echocardiography | All patients ⩾65 with clinical risk factors: diabetes, hypertension, peripheral vascular disease, ischaemic heart disease; all patients ⩾65 not in high risk group | All patients aged <65 with no history of embolism, hypertension, diabetes, or other clinical risk factors | |
| ACC/AHA/ESC guidelines (2001)1 | Aged ⩾60 years with diabetes or CAD; aged ⩾75 years (especially women); any age with risk factors (clinical heart failure, LVEF ⩽35%; thyrotoxicosis, or hypertension); rheumatic heart disease, prosthetic heart valves; previous thromboembolism; persistent atrial thrombus on TOE | Aged <60 years with CAD but no risk factors; aged ⩾60 years and risk factors | Aged <60 years and no risk factors | |
| CHADS2* (2001)w25, (2004)w26 | 3–6 | 1–2 | 0 | |
| Framingham (2003)w27 | Complicated weighted point scoring system—points are given for the following risk factors: ↑ age (maximum score ⩽10); sex (female = 6, male = 0); ↑ blood pressure (⩽4); and diabetes (6). Total score (maximum 31 points) corresponds to a predicted 5 year stroke risk | |||
| ACCP (2004)2 | Prior stroke, TIA, or systemic embolic event; aged >75 years; moderately to severely impaired LV function with or without CHF; hypertension or diabetes | Aged 65–75 years with no other risk factors | Aged <65 years with no risk factors | |
*Score one for each of the following: recent congestive heart failure, hypertension, aged ⩾75 years, diabetes. Score two if there is a history of stroke or transient ischaemic attack. Total score available is six. Although the original CHADS paperw25 did distinguish between high and low risk, the intermediate risk category was not defined until a subsequent analysis.w26
ACC, American College of Cardiology; ACCP, American College of Chest Physicians; AFI, Atrial Fibrillation Investigators; AHA American Heart Association; CAD coronary artery disease; CHF congestive heart failure; ESC European Society of Cardiology; LV, left ventricular; LVEF left ventricular ejection fraction; SBP systolic blood pressure; SPAF, stroke prevention in atrial fibrillation; TIA transient ischaemic attack; TOE transoesophageal echocardiography.