TAMPA — More than 10% of patients with low to intermediate risk for coronary heart disease have an abnormal ankle brachial index, putting them at a higher risk for MI and coronary death than predicted by conventional measures.
In a study of 822 individuals screened for peripheral artery disease (PAD), 11% of those with a low-risk Framingham Risk Score (FRS) for coronary disease and 13% of those with an intermediate-risk score had an abnormal ankle brachial index (ABI).
Abnormal ABI has been associated with increased risk of coronary heart disease (CHD) events and mortality, even in individuals at low to intermediate CHD risk (JAMA 2008;300:197-208), but prevalence estimates of abnormal ABI among older screening populations with low-intermediate FRS have not been reported previously.
“The prevalence of abnormal ABI is high, even in those a without high Framingham Risk Score. … The use of abnormal ABI in screening has the potential to improve risk prediction,” Dr. Raj Dhangana said.
The findings are good news, given that at least 60% of CHD events occur in individuals who were not known to be at high risk (BMJ 2003;327:1267). In fact, almost two-thirds of events occur in individuals who are at low or intermediate risk using the FRS (Am. Heart J. 2002;144:95-100).
The use of ABI for screening could help improve risk prediction for CHD, said Dr. Dhangana, a research fellow at Rhode Island Hospital, Providence.
The researchers analyzed data from the PEDAL Study (Population-Based Examinations to Determine Ankle-Brachial Index)—a multicenter, cross-sectional study conducted at 23 sites of the Legs for Life national free public PAD screening program in 2007-2009.
The FRS was calculated for each participant to determine 10-year risk of CHD. Based on their FRS, patients were stratified into three risk categories: low (less than 6%), intermediate (6%-19%), and high (at least 20%). An abnormal ABI was defined as less than 0.9 and/or greater than 1.4 in either leg.
A low FRS was observed in 256 individuals (31%), and 414 (50%) had an intermediate risk.
Disclosures: Dr. Dhangana has no relevant financial conflicts.
Ankle brachial index may help detect individuals at risk for coronary events.
Source ©Society of Interventional Radiology/www.SIRweb.org