Variability of Doppler ankle pressures with arterial occlusive disease: an evaluation of ankle index and brachial-ankle pressure gradient.

The variability of Doppler ankle pressures was studied in 35 men with clinically stable claudication. An average of 6.8 measurements was obtained from each man. The mean range of ankle index was 0.18 with a mean standard deviation of 0.07. The brachial-ankle pressure gradient had a wider spread, with a mean range of 38 mm Hg and a standard deviation of 13.9. The amount of variation in a given patient was unrelated to mean blood pressure or mean ankle index. The results of this study show that the ankle index must change at least 0.15 before it can be considered significant. Based on the variability found, we recommend that multiple baseline determinations be obtained on patients who are to be followed longitudinally.