Patterns of skin flowmotion in the lower limbs of patients with chronic critical limb ischaemia (CLI) and oedema.

Abstract

To study flowmotion (FM) in lower limbs with critical limb ischaemia (CLI) and oedema and to elucidate FM patterns when skin viability is threatened. Fourteen patients with unilateral CLI and oedema and two control groups were included - one consisting of 10 healthy participants and the other nine patients with unilateral CLI without oedema. Laser Doppler was used to evaluate the foot skin microcirculation simultaneously at four different areas, with the limbs in supine and dependent position. FM was expressed using fast Fourier transformation (FFT) as low frequency (LF) and high frequency (HF) waves and their respective FFT-powers. All patients with CLI, both with and without oedema, showed HF waves in both diseased and contralateral limbs. These were absent in healthy controls. There were no regional differences in frequency in the critically ischaemic feet (with and without oedema) and between ischaemic and their contralateral feet. Changing the position of ischaemic limbs from supine to dependency had no significant effect on the frequency, while a significant increase of the median FFT-powers of LF and HF waves at the pulp of the first toe was observed. This manoeuvre resulted in decrease of the median FFT-powers of LF in healthy controls. HF waves are associated with CLI. Ischaemia also appears to influence the FFT-power of each frequency domain. Ischaemic oedema does not seem to affect the pattern of FM in the foot of patients with CLI.