Cut-off value of the ankle-brachial pressure index at which the accuracy of brachial-ankle pulse wave velocity measurement is diminished

Background The present study was conducted to establish the cutoff value of the ankle-brachial pressure index (ABI) at which the accuracy of brachial-ankle pulse wave velocity (baPWV) measurement is diminished. Methods and Results The baPWV and ABI were measured in 1,361 patients with an atherosclerosis-related disease and 7,889 subjects without any atherosclerotic risk factors, in order to determine the percent difference of the brachial-ankle PWV (%baPWV), the angle of the rise of the anacrotic limb (%angle) and of the amplitude of the entire waveform (%amplitude) in both sides. The %angle and %amplitude were significantly higher in subjects whose %baPWV was greater than or equal to19% than in those subjects whose %baPWV was <19% (19% was the mean value+3SD of 7,889 healthy subjects). The %baPWV greater than or equal to19% was defined as the abnormal discrepancy of baPWV caused by arterial stenosis in both sides. The receiver operator characteristic curve discriminated the abnormal discrepancy of baPWV by ABI because the area under the curve was 0.86. The highest discriminating sensitivity and specificity were 91% and 75% at ABI=0.95. Conclusion An ABI <0.95 seems to be the marker of diminished baPWV accuracy.