CHA₂DS₂-VASc modestly predicts ischemic stroke, thromboembolism, death in heart failure patients with and without afib

A common clinical risk score predicted ischemic stroke, thromboembolism, and death among patients with heart failure with or without atrial fibrillation, but only modestly, according to a study.

Danish researchers used registries to examine the CHA₂DS₂-VASc score (congestive heart failure, hypertension, age 75 years or older [doubled], diabetes, stroke/transient ischemic attack/thromboembolism [doubled], vascular disease [prior heart attack, peripheral artery disease, or aortic plaque], age 65-75 years, sex category [female]) to predict ischemic stroke, thromboembolism, and death within 1 year in patients with a new diagnosis of heart failure with and without afib. The study included 42,987 patients (22% percent with concomitant afib) not receiving anticoagulation who were diagnosed as having new-onset heart failure from 2000 to 2012. CHA₂DS₂-VASc scores (which are based on 10 possible points, with higher scores indicating higher risk) were stratified by presence of afib at study entry.

Results appeared online Aug. 30 in the Journal of the American Medical Association.

Patients with heart failure had a high risk of ischemic stroke, thromboembolism, and death regardless of whether afib was present. However, the CHA₂DS2-VASc score was only modestly able to predict these outcomes. Patients without afib had a 3.1% risk of ischemic stroke, 9.9% risk of thromboembolism, and 21.8% risk of death during follow-up. The researchers compared rates of stroke and death for patients with CHA₂DS2-VASc scores ranging 1 through 6:

• ischemic stroke with concomitant afib: 4.5%, 3.7%, 3.2%, 4.3%, 5.6%, and 8.4%;
• ischemic stroke without concomitant afib: 1.5%, 1.5%, 2.0%, 3.0%, 3.7%, and 7%.
• all-cause death with concomitant afib: 19.8%, 19.5%, 26.1%, 35.1%, 37.7%, and 45.5%;
• all-cause death without concomitant afib: 7.6%, 8.3%, 17.8%, 25.6%, 27.9%, and 35.0%.

At high CHA₂DS₂-VASc scores, the absolute risk of thromboembolism was high regardless of presence of afib, for example, with a score of 4, clot risk was 9.7% for patients without concomitant afib versus 8.2% for those with afib.

The authors wrote, “The poor prognosis of AF [afib] for ischemic stroke and death in patients with HF [heart failure] was evident in our study, but the observation that additional risk factors in patients with HF are particularly significant among those without AF is an important result. Indeed, preventative strategies to reduce ischemic stroke and TE [thromboembolism] risk in this large patient population require further investigation.”