CHA2DS2-VASc refines stroke risk in ‘low-risk’ AF patients after ablation
MedWire News: Stroke risk scores, particularly the CHA2DS2-VASc score, can help to determine which patients remain at high risk for thromboembolic events after undergoing catheter ablation for atrial fibrillation (AF), research suggests.
Notably, the CHA2DS2-VASc score was able to identify patients who were at low risk according to their CHADS2 score, yet remained at high risk for stroke.
Shih-Ann Chen (Taipei Veterans General Hospital, Taiwan) and co-workers followed up 565 AF patients for an average of 39.2 months after they underwent catheter ablation. During this time, 4.8% of patients died or had a thromboembolic event (ischemic stroke, transient ischemic attack, peripheral embolism, or pulmonary embolism).
The only independent predictors of thromboembolic events were recurrence of AF despite multiple ablations and CHADS2 or CHA2DS2-VASc score. The event rate rose in line with CHADS2 score, from 1.2% to 100.0% of patients with scores of 0 and 6, respectively, and there was a similar pattern for CHA2DS2-VASc scores. CHA2DS2-VASc is an updated version of CHADS2, which places greater emphasis on age over 75 years and incorporates vascular disease, age 65-74 years, and gender.
The overall ability of the two scores to differentiate between patients who did and did not have an adverse event was not significantly different, the team reports in the Journal of the American College of Cardiology.
However, the CHA2DS2-VASc score was able to further subdivide patients categorized as low risk by the CHADS2 score. The event rate among patients with a CHADS2 score below 2 was just 2.4%, compared with 15.2% among those with higher scores, but in this apparently low-risk subgroup the adverse event rate rose from 0.6% among patients with a CHA2DS2-VASc score of 0, to 11.8% among those with a score of 3.
Editorialists Ganesh Venkataraman and S Adam Strickberger (Washington Hospital Center, DC, USA) note that CHA2DS2-VASc has been included in the latest European AF guidelines, but not the most recent US guidelines.
"Perhaps this is why healthcare providers in the United States mainly utilize the CHADS2 risk stratification scoring system to help guide antithrombotic therapy in patients with AF," they say.
They stress: "For patients with AF and a CHADS2 score of 0 or 1, the CHA2DS2-VASc score may help to identify the 'low risk' patient at 'high risk' for a [thromboembolic] event."
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By Eleanor McDermid