An Evaluation of the Efficacy of Methods Used in Screening for Lower-Limb Arterial Disease in Diabetes: Response to Williams et al.

We have read with interest the report by Williams et al. (1) on diabetic limbs without critical ischemia. We have recently performed a similar study in 106 diabetic patients with polyneuropathy, 61 of whom had critical ischemia (2), which confirms the poor performance of ankle-brachial pressure index in these patients (1, 2). At variance to Williams et al. (1), we were, however, able to demonstrate the usefulness of the pulsatility index to predict critical ischemia. A pulsatility index <1.2 recorded at the ankle arteries predicted critical limb ischemia with reasonably good sensitivity (0.87) and specificity (0.62); the positive and the negative predictive values were 0.64 and 0.86, respectively. We explain our differences to the findings of Williams et al. by the different Doppler devices that were employed. While Williams et al. had used a 8-MHz Doppler probe (1), we used a 10-MHz linear ultrasound probe with a color-flow duplex machine (Accuson 128XP10; Acuson, Mountain View, CA) in our study.