CHA2DS2-VASc best for on-anticoagulation stroke prediction
MedWire News: The CHA2DS2-VASc is the most accurate contemporary risk stratification scheme for predicting which atrial fibrillation (AF) patients remain at high risk for stroke despite being on oral anticoagulation, research shows.
CHA2DS2-VASc was the best performer of eight risk stratification schemes, the other seven being CHADS2, the Framingham risk score, guidelines from the National Institute for Clinical Excellence (NICE 2006), the American College of Cardiology/American Heart Association/European College of Cardiology (2006), and the American College of Chest Physicians (8th edition).
The CHA2DS2-VASc scheme was derived from CHADS2, but gives more weight to the age ≥75 years and previous stroke elements and also includes vascular disease, age 65-74 years, and female gender.
In the current study, which included 7329 AF patients on anticoagulation, all eight schemes had similar ability to distinguish between the 184 patients who suffered a thromboembolic event and those who did not, ranging from 57.5% for NICE 2006 to 64.7% for CHA2DS2-VASc.
However, CHA2DS2-VASc correctly categorized 98.4% of the patients who suffered thromboembolism as high risk, whereas the other schemes categorized no more than two-thirds of these patients as high risk.
Gregory Lip (City Hospital, Birmingham, UK) and team also stress that 99.5% of patients categorized as low risk by CHA2DS2-VASc remained free of thromboembolism, which they say is "reassuringly high" and, again, more accurate than any other scheme.
Of individual risk factors, those that independently predicted thromboembolism were previous stroke or transient ischemic attack, age of at least 75 years, the presence of coronary artery disease, and current smoking.
In contrast, patients who drank alcohol were less likely to suffer thromboembolism than those who did not.
"Identification of patients who remain at high risk for stroke despite anticoagulation may affect treatment strategies in clinical practice," concludes the team in the journal Stroke.
"Outside of the clinical trial setting, maintenance of an adequate time in the therapeutic range is more difficult to attain, but this would be of paramount importance in anticoagulated AF patients at high risk to reduce the risk of thromboembolism or major hemorrhage."
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By Eleanor McDermid