NEW YORK - A variant of the CHADS2 score that's used to estimate ischemic stroke risk in patients with atrial fibrillation (AF) is also modestly accurate in heart failure patients, even in those without AF, researchers say. The variant, CHA2DS2-VASc, calculates stroke risk based on 10 possible points with higher scores indicating higher risk.
Line Melgaard from Aalborg University in Denmark and colleagues used three Danish nationwide registries to investigate whether the CHA2DS2-VASc score could predict ischemic stroke, thromboembolism, and death in patients with heart failure without AF as effectively as it does in patients with AF.
Patients with heart failure had a high risk of all three outcomes, whether or not AF was present, and the CHA2DS2-VASc score modestly predicted these endpoints at one-year and five-year follow-up (C statistics, 0.67 and 0.69, respectively).
Heart failure patients without AF whose CHA2DS2-VASc score was 4 or higher had increased risks of ischemic stroke, thromboembolism, and death in a manner comparable to patients with AF, according to the August 30 JAMA online report.
The negative predictive value (NPV) was around 90% at one-year follow-up for all three outcomes, although NPVs were strongly attenuated by the five-year follow-up.
"In our study, one of our principal findings was that the absolute risk of ischemic stroke among patients without AF was about 1.5% per year or higher with CHA2DS2-VASc scores of 2 or higher, with associated five-year absolute ischemic stroke risks in excess of 4% or more," the researchers noted. This risk level would be sufficient to prompt initiation of long-term anticoagulation in patients with AF, they say.
"The poor prognosis of atrial fibrillation for ischemic stroke and death in patients with heart failure was evident in our study and expected," Melgaard said. "But the observation that additional risk factors in patients with heart failure are particularly significant among those without atrial fibrillation is an important and (to some extent) unexpected result."
"I hope physicians will recognize that patients with heart failure and sinus rhythm have an increased risk of ischemic stroke, and that some subgroups within this population most likely need thromboprophylaxis," Melgaard concluded. "Especially patients with multiple comorbidities (high CHA2DS2-VASc score) need attention in the clinic."