Among patients with heart failure with or without atrial fibrillation, use of a common clinical risk score was associated with risk of ischemic stroke, thromboembolism (blood clot), and death; however, predictive accuracy was modest, and the clinical usefulness of this score in patients with heart failure remains to be determined, according to a study appearing in JAMA. The study is being released to coincide with its presentation at the European Society of Cardiology Congress 2015.

Heart failure (HF) is associated with an increased risk of ischemic stroke and death. Risk stratification using readily available clinical variables may help identify sub­groups at low and high risk of ischemic stroke and thromboembolic events (TE) in an HF population. 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]) is already used clinically for stroke risk stratification in patients with atrial fibrillation (AF). Its usefulness in a population of patients with HF has been unclear, according to background information in the article.

Gregory Y. H Lip, M.D., of Aalborg University, Aalborg, Denmark, and colleagues investigated whether CHA2DS2-VASc predicts ischemic stroke, thromboembolism, and death within one year in patients with a new diagnosis of HF with and without AF. Using Danish registries, the study included 42,987 patients (22 percent with concomitant [accompanying] AF) not receiving anticoagulation who were diagnosed as having new onset HF during 2000-2012. End of follow-up was December 31, 2012. Levels of the CHA2DS2-VASc score (based on 10 possible points, with higher scores indicating higher risk) were stratified by presence of AF at study entry.

The researchers found that pa­tients with HF had a high risk of ischemic stroke, TE, and death whether or not AF was present. However, the CHA2DS2-VASc score was only modestly able to predict these outcomes. At high CHA2DS2-VASc scores, patients with HF without AF had high absolute risk of ischemic stroke, TE, and death, and the absolute risk increased in a comparable manner in patients with HF, with and without AF. The absolute risk of thromboembolic com­plications was higher among patients without AF compared with patients with concomitant AF with high CHA2DS2-VASc scores.

"The poor progno­sis of AF for ischemic stroke and death in patients with HF 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 risk in this large patient population require further investigation," the authors write.