Background:
The ankle-brachial index is a simple and effective tool for diagnosing peripheral artery disease, but has not been validated for the diagnosis of coronary artery disease. The aim of this study was to evaluate the ability of the ankle-brachial index to predict coronary artery disease in patients undergoing coronary angiography.
Methods:
Patients with clinical suspicion of coronary artery disease and indication for coronary angiography were prospectively evaluated. Significant coronary artery disease was defined as the presence of stenosis > 70% of at least one major epicardial coronary artery or any of their major branches. A ROC curve was developed to define the ankle-brachial index cutoff that best predicts coronary artery disease.
Results:
A total of 312 patients were evaluated: mean age was 57 ± 11 years and 50% were male. One hundred and sixteen (37.2%) patients had significant coronary disease. Ankle-brachial index measurement in these patients was significantly lower than in those without coronary artery disease (0.88 ± 0.14 vs. 0.96 ± 0.87; p < 0.01). Ankle-brachial index < 0.87 showed a sensitivity of 31%, specificity of 95.4%, positive predictive value of 75.9% and negative predictive value of 71.6%. The area under the ROC curve was 0.73 (95% confidence interval of 0.67-0.79).
Conclusions:
Ankle-brachial index < 0.87 had a high specificity to predict significant coronary disease. Considering its low cost and ease of use, measurement of ankle-brachial index may be incorporated to daily clinical practice to help diagnose significant coronary artery disease.
Atherosclerosis; Cardiovascular diseases; Ankle brachial index; Risk factors; Coronary angiography
