A comparison of Doppler ankle pressures and skin perfusion pressure in subjects with and without diabetes.

Doppler ankle pressure measurements may be misleading in some patients because medial calcification has made the arteries of the leg incompressible. This problem is especially common in diabetics. Medical calcification that is not severe enough to make an artery clinically incompressible may cause an increased stiffness of the arterial wall that will limit the accuracy of Doppler ankle pressure measurements. A comparison of skin perfusion pressure, using an isotope technique, and Doppler ankle pressures was made in 226 subjects, diabetic and non-diabetic. Patients with incompressible arteries were excluded from the study. The slopes of the regression lines relating skin perfusion pressure to Doppler ankle pressure in diabetic and non-diabetic subjects were significantly different (P = 0.03). This result was consistent with the hypothesis that diabetic subjects have arteries that are less compressible than normal arteries and may make Doppler ankle pressure measurements in diabetic subjects misleading over the whole range of pressures recorded.