NEW YORK (Reuters Health) – Inclusion of the ankle-brachial index (ABI) may better define the prevalence of vascular disease in patients with non-valvular atrial fibrillation (NVAF), according to new research.
As Dr. Francesco Violi told Reuters Health by email, “The study provides the first evidence that in NVAF patients ABI, which is a marker of systemic atherosclerosis, is reduced in about 20% of patients suggesting that its inclusion in CHA2DS2-VASc score will improve the predictive value of the score.”
The CHA2DS2-VASc stroke risk score is based on factors including congestive heart failure (or left ventricular systolic dysfunction), age, diabetes, peripheral artery disease and gender.
In a paper online August 14 in the Journal of the American College of Cardiology, Dr. Violi of Sapienza University of Rome and colleagues note that NVAF patients have a fivefold increase in stroke risk. They often suffer from atherosclerotic complications, but the presence of peripheral artery disease in NVAF is unclear.
To investigate, the researchers studied more than 2,000 patients and found that 428 (21%) had an ABI of 0.90 or less, indicating that NVAF is often associated with systemic atherosclerosis.
Patients with a low ABI score were significantly more likely to be hypertensive, diabetic, to be smokers and to have experienced transient ischemic attack or stroke. A significantly greater proportion of this group had a CHA2DS2-VASc score of 2 or higher compared with those with an ABI greater than 0.90 (93% vs. 82%; p<0.0001).
The overall NVAF population was at high risk for stroke, with only 14% having a CHA2DS2-VASc score of 0-1; the remainder had a score of 2 or higher. Despite this, 16% were untreated with any antithrombotic drug, 19% were treated with antiplatelet drugs and 61% with oral anticoagulants. The rest were treated with both.
Addition of an ABI score below 0.90, say the researchers, would lead to a higher number of NVAF patients being anticoagulant treatment candidates. A prospective study, they add, is necessary to validate the risk score of this new definition of vascular disease. Dr. Violi said such a study is already ongoing.
J Am Coll Cardiol 2013.