PALM BEACH, FLA. – The ankle-brachial index value is directly associated with the prevalence of carotid artery stenosis and with a history of coronary artery disease and cerebrovascular disease, according to analysis of more than 3.6 million records obtained from the private health screening company, Life Line Screening.
But what makes the study interesting is the database itself, and not so much the findings, which have been previously shown, commented Dr. Spence M. Taylor, president of the Greenville Health System Clinical University, Greenville, South Carolina.
Life Line Screening has mobile units, which travel to various locations and for a fee of more than $100, screen individuals, collecting nearly 300 data points per person. Meanwhile, the ankle-brachial index (ABI) costs less than $30 approximately. Yet, the test hasn’t become widely used, despite the evidence. Not much has changed since the 2001 PARTNERS study, which showed that the primary care physicians’ awareness of PAD diagnosis was "relatively low" (JAMA 2001;286:1317-24).
Dr. Mark A. Adelman
Results using the Life Line Screening’s large database may show the federal government that ABI can be cost effective, and getting them on board would popularize the screening tool, said Dr. Mark A. Adelman of the NYU Langone Medical Center, who presented his study at the Southern Association for Vascular Surgery annual meeting.
"Life Line is a huge paradox," said Dr. Taylor, senior associate dean of academic affairs at University of South Carolina, Greenville. It’s an operation that "we love to hate and hate to love," he added.
Dr. Adelman, the Frank J. Veith, M.D. Professor of Vascular and Endovascular Surgery and chief of vascular surgery at NYU Langone, and his colleagues analyzed data obtained from Life Line Screening, and found that individuals with an ABI between 0.41 and 0.60 had a 26.4% incidence of carotid artery stenosis (CAS), compared with individuals who had a normal ABI. The incidence increased to 35% for patients with ABI of 0.4 or less.
The majority of the abnormal ABI cases were between 0.81 and 0.90.
The analysis by Dr. Adelman and his colleagues also showed that individuals with PAD were more likely to be aged 70 years or older, male, and have modifiable risk factors, such as a history of smoking, hypertension, diabetes, and hypercholesterolemia, compared with non–PAD persons (P less than .001). (A comparison of Life Line’s database to one from the general population showed that the risk factors such as hypertension, hyperlipidemia, diabetes, and smoking were comparable.)
PAD subjects were also more likely to have CAS, prior stroke, prior transient ischemic attack, prior MI, and prior coronary revascularization, compared with those who didn’t have PAD (P less than .001). There was a significant correlation between decreasing ABI value and an increase in the prevalence of CAS, CAD, and cardiovascular disease (P less than .001).
In a separate study analyzing the same database, Dr. Adelman and his colleagues found that modifiable risk factors, such as hypertension and smoking, are associated with increased prevalence of peripheral vascular disease (J. Vasc. Surg. 2013;58:673-81).
Dr. Adelman said that screening for ABI could trigger other screening and lead to modification of risk factors that could affect better patient outcomes, changes in lifestyle, or changes in pharmacological management.
Dr. Adelman and Dr. Taylor had no disclosures.
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