Clinical scores incorporate risk factors such as congestive heart failure, hypertension, age, diabetes mellitus and prior stroke to calculate stroke risk for patients with atrial fibrillation, a common but serious heart arrhythmia. CHADS2 is the most commonly used score, but is suboptimal because it classifies a substantial number of patients as having an intermediate or indeterminate risk. In recent years, European investigators developed a new score, CHA2DS2-VASc, which performed better than CHADS2 in European populations, but until now has not been tested in an American multiethnic population.
“Clinical risk scores are useful in identifying patients with atrial fibrillation at high enough risk for having a stroke to warrant anticoagulation with coumadin,” said Howard Willens, M.D., associate professor of clinical cardiology and first author on the study.
In the study “Correlation of CHADS2 and CHA2DS2-VASc Scores with Transesophageal Echocardiography Risk Factors for Thromboembolism in a Multiethnic United States Population with Nonvalvular Atrial Fibrillation,” Willens and his team compared both scores in 167 patients, including 40 percent who were either Hispanic or African American.
The researchers found that age, heart failure and diabetes were independent predictors of left atrial appendage abnormalities, while ethnicity was not. Also, the CHADS2 risk category of 21 percent of patients was upgraded by the CHA2DS2-VASc scheme.
Of the 30 intermediate-risk patients by the CHADS2 score upgraded to high risk using CHA2DS2-VASc score, eight (27 percent) had at least one transesophageal echocardiographic (TEE) risk factor for thromboembolism.
The team concluded that while the CHA2DS2-VASc score classifies fewer patients as an intermediate risk and has increased sensitivity for detecting abnormalities of the left atrial appendage, it also had marked decreased specificity and lower ability for predicting TEE risk factors for thromboembolism in this population.
“Further studies on the relationship of the CHA2DS2-VASc score with outcomes in nonvalvular atrial fibrillation are warranted in larger multiethnic populations before its widespread adoption in the United States,” said Willens.
Other co-authors of the study are Mauro Moscucci, M.D., M.B.A., Interim Chair of Medicine and Chief of the Cardiovascular Division; Orlando Gómez-Marín, M.Sc., Ph.D., professor of epidemiology and public health; resident Andrew DeNicco, M.D., and Katarina Nelson, M.D., former cardiology fellow.
University of Miami