CHA2DS2-Vasc Score Predicts Stroke/Embolic Risk in Heart Failure

August 30, 2015

LONDON, UK — The CHA2DS2-VASc score, which is already used to assess stroke and thromboembolic risk in patients with atrial fibrillation (AF), may also be useful for this purpose in patients with heart failure, a new study suggests[x].

The study found that in patients with incident heart failure with or without AF, the CHA2DS2-VASc score was associated with risk of ischemic stroke, thromboembolism, and death.

The study was presented today at the European Society of Cardiology 2015 Congress by Line Melgaard (Aalborg University Hospital, Denmark) as part of the Young Investigators Awards session. It was also simultaneously published in the Journal of the American Medical Association.

Melgaard commented to heartwire from Medscape, "We found a C statistic of 0.64 for the CHA2DS2-VASc score in predicting stroke risk in heart-failure patients without AF. Generally a C statistic above 0.70 signifies good utility and one below 0.60 means poor utility, so our result suggests an intermediate value for this score for evaluating risk of stroke and thromboembolic events in heart-failure patients."

Consider Anticoagulant Therapy

Line Melgaard

She added: "Our results also suggest that heart-failure patients without AF who have a CHA2DS2-VASc score of 3—that means they have two additional risk factors—could be good candidates for anticoagulant therapy."

Melgaard cautioned that because these results come from an observational study they needed to be confirmed in a randomized trial. "This study won't change the guidelines, but it does suggest that physicians need to pay attention to the idea that heart-failure patients without AF are at risk of stroke and thromboembolic events and that this risk increases with each additional comorbidity present."

The study also found that in patients with heart failure and CHA2DS2-VASc scores of 4 or more, the absolute risk of ischemic stroke, thromboembolic events, and death was very high. Melgaard noted: "Heart-failure patients with these higher CHA2DS2-VASc scores without AF actually had a higher risk of thromboembolic events than those with AF. This suggests that it may not just be AF that is causing stroke and embolic events and that there may be additional mechanisms at play in heart-failure patients."

For the study, the researchers linked data from three Danish nationwide registries—the National Patient Register (which records all hospital admissions and diagnoses); the National Prescription Registry (which contains data on all prescriptions dispensed from Danish pharmacies); and the Civil Registration System (which holds information on date of birth, date of death, and sex of all persons living in Denmark).

The study population included 42,987 patients aged 50 years or older discharged with a primary diagnosis of incident heart failure between 2000 and 2012. Of these, 21.9% had a diagnosis of AF at baseline. Patients taking anticoagulants were excluded.

Based on the CHA2DS2-VASc score, patients were given 1 point for congestive heart failure, hypertension, age 65 to 74 years, diabetes mellitus, vascular disease, and female sex and 2 points for age 75 years or older and previous thromboembolism. Therefore, a score of 1 corresponds to patients with heart failure only and no additional stroke risk factors.

Results showed that risks of ischemic stroke, thromboembolism, and death were greater with increasing CHA2DS2-VASc scores both for patients with and without concomitant AF.

Incidence Rate of End Points (%) at 1 Year After Heart-Failure Diagnosis

  Number of CHA2DS2-VASc risk factors
  1 2 3 4 5 >6
Patients without AF            
Ischemic stroke 0.4 0.4 0.6 1.0 1.3 2.6
Thromboembolic events 1.6 2.0 2.6 3.5 4.5 7.5
Death 2.1 2.4 5.7 8.7 9.8 12.9
Patients with AF            
Ischemic stroke 1.5 1.0 1.1 1.7 2.2 3.6
Thromboembolic events 3.3 2.9 3.0 3.4 4.7 6.9
Death 2.0 4.2 9.5 13.8 15.0 18.9
Thromboembolic events=Composite end point of ischemic stroke, transient ischemic attack, systemic embolism, pulmonary embolism, or acute MI

In the paper, the authors note that in the general AF population, a stroke risk of greater than 1% per year is often used as a cut point to identify patients in whom the benefits of long-term oral anticoagulation may outweigh the risks of bleeding.

In the present heart-failure population, patients without AF with a CHA2DS2-VASc score of 2 or higher had a stroke risk greater than 1% per year.

They write: "Although it is not clear whether this cut point would apply directly to the heart-failure population without AF, our results may suggest that subgroups of patients with heart failure without AF and with two or more components of the CHA2DS2-VASc score besides HF are at high enough risk of ischemic stroke to benefit from anticoagulation therapy, especially with availability of the non–vitamin-K antagonist oral anticoagulants."

Melgaard reports no relevant financial relationships. Disclosures for the coauthors are listed in the article.

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