Assessing peripheral arteries in South African black women with type 2 diabetes mellitus

To determine the value of ankle and toe blood pressure indices and pedal pulse palpation in the assessment of peripheral arterial disease in subjects with type 2 diabetes mellitus (DM).

Cross-sectional study.

A convenience sample of 85 female subjects with type 2 DM underwent a series of peripheral vascular assessments at the diabetes clinic of a community hospital.

Palpation of the pedal pulses, Doppler-derived ankle brachial systolic blood pressure indices, photo plethysmographic-derived toe brachial systolic blood pressure indices and antero-posterior radiographs of both feet.

Mean values were 1.15 (standard deviation (SD): 0.17) and 0.76 (SD: 0.17) for ankle brachial index (ABI) and toe brachial index (TBI) respectively. The differences between the two indices increased from 0.36 (95% confidence interval (CI): 0.32-0.41) to 0.58 (95% CI: 0.46-0.70) depending on whether ABI was less or greater than 1.3. The correlation coefficient for left versus right foot was 0.62 and 0.71 for ABI and TBI respectively. The relationship between ABI and TBI is non-linear with a cut point close to 1.3. Both ABI and TBI were significantly lower in subjects who had both pedal pulses absent on palpation.

The relationship between ABI and TBI is linear below an ABI of 1.3. but with a wide 95% prediction interval. If both pedal pulses are absent the ABI is significantly diminished compared with when both pulses are present, even though not necessarily below 0.9.