Diagnosis of peripheral arterial disease in general practice: can the ankle-brachial index be measured either by pulse palpation or an automatic blood pressure device?

BACKGROUND: Despite its validity as a screening test for peripheral arterial disease (PAD), and its prognostic value, the ankle-brachial index (ABI) is infrequently used in primary care, probably because a Doppler device is required, along with the requisite skill for its use. We hypothesized that ABI could be accurately measured either by pulse palpation (pABI) or automatic blood pressure devices (autoABI) instead of Doppler method (dABI). DESIGN AND METHODS: In 54 subjects, we compared the results and the intra-observer reproducibility of pABI to dABI, as well as the inter-observer reproducibility of both pABI and autoABI to dABI. Arm and ankle systolic pressures were measured by the three methods by two observers. The first observer repeated pABI and dABI measurements. The results were compared by the Student paired t-test. Reproducibility was assessed by the intra-class correlation coefficient of agreement (R) and the Bland and Altman method.
RESULTS: The mean dABI obtained by the first observers was 1.03 +/- 0.26 vs. a pABI of 0.85 +/- 0.44 (p < 0.0001) and an autoABI of 1.09 +/- 0.31 (p < 0.05). The intra-observer R-coefficient was at 0.89 for dABI vs. 0.60 for pABI (p < 0.05). The inter-observer R-coefficients were 0.79 for dABI vs. 0.40 for pABI (p < 0.05) and 0.44 for autoABI (p < 0.05).
CONCLUSION: Neither pulse palpation nor automatic oscillometric devices can be recommended as reliable methods for ABI measurement.