The CHADS-based risk scores can predict long-term vascular outcomes and mortality in patients with stroke who do not have atrial fibrillation (AF), research suggests.
The original CHADS2 score - developed to predict stroke in AF patients - and the modified version, CHA2DS2-VASc, predicted recurrent stroke, major cardiovascular events, and death in a large cohort of ischemic stroke survivors.
"These scores may provide a simple means of stroke-risk stratification, even in non-AF patients with stroke," lead researcher George Ntaios (University of Thessaly, Larissa, Greece) and team write in Neurology.
The study included 1757 patients among whom, over a median of 33 months, there were 232 recurrent strokes, 124 cardiovascular events, and 34 sudden deaths. Cumulative 5-year survival significantly differed according to patients' CHADS2 scores, at 79.0% among 262 patients with a score of 0 (low risk), 60.6% among 617 with a score of 1 (intermediate risk), and 44.5% among those with scores of 2-6 (high risk).
There was a similar pattern for CHA2DS2-VASc scores, except that survival was not significantly different between the low- and intermediate-risk groups (87.8 and 85.4%, respectively), apparently because CHA2DS2-VASc scoring concentrated patients into the high-risk group, with scores of 2-9.
Although the CHADS scoring systems were developed in patients with AF, the major components - heart failure, hypertension, age, diabetes, and prior stroke - are all known to contribute to poor outcomes after stroke. In this study, the most common risk factor in patients with low scores was hypertension, which is a long-established risk factor for recurrent stroke.
This explains the ability of the CHADS scores to predict outcome in stroke patients without AF, say Ntaios et al.
On multivariate analysis, being in the intermediate- or high-risk group according to CHADS2 scores, or being in the high-risk group according to CHA2DS2-VASc scores, raised patients' risk for death, recurrent stroke, or cardiovascular events a significant two- to threefold.
The researchers note that the stroke risk factors in the CHADS scores may themselves be an indicator for AF risk, with the arrhythmia reportedly identifiable in about a third of patients with stroke risk factors.
"Whether patients with CHADS2 risk factors but without a history of AF might benefit from implantable monitors for the selection and administration of anticoagulation for primary stroke prevention merits additional investigation," they comment.
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