A near-infrared spectroscopy-assisted test discriminates patients with peripheral arterial disease and venous insufficiency with changes of foot oxygenation following light elastic compression therapy


Background: Elastic compression therapy (CT) in patients with peripheral artery disease (PAD) and chronic venous insufficiency (CVI) may compromise arterial perfusion. We evaluated the feasibility of a toe-flexion test, which quantifies dynamic foot perfusion by near-infrared spectroscopy (NIRS), for the assessment of hemodynamic sustainability of CT in PAD patients with CVI. Patients and methods: In this prospective observational study, PAD patients aged 50–85 with combined CVI at CEAP stages II–IV were studied. The ankle-brachial index (ABI) was measured, and foot perfusion was determined after 10 consecutive toe-flexion movements with NIRS sensors placed on the dorsum of each foot. Knee-high open-toe compression stockings were applied, and the degree of compression was measured. Toflex-area was determined by calculating the area under the curve of the oxygenated hemoglobin track recorded by NIRS. A toflex-area reduction > 20 % following CT was arbitrarily defined to identify limbs of patients with improved foot perfusion. These subjects received CT to be worn and a diary to report adherence and symptoms. Results: Forty-seven PAD patients (74 ± 9 years; ABI 0.67 ± 0.24) with CVI were enrolled. For all legs, superimposable toflex-areas were observed for the first two attempts (ICC 0.92). Following application of CT (17 ± 2 mmHg), the toflex-area improved (from –162 ± 110 a.u. to –112 ± 104 a.u.; p < .001). Sixty-two limbs (n = 32 patients) exhibited improved foot perfusion after CT, with a mean variation of 80 ± 47 a.u., while 32 limbs (n = 23 patients) showed stable or worsened values. In a regression model, favorable variations in toflex-area after CT were linked to a worse baseline toflex-area (R2 = 0.18; p < 0.001; rpartial = –0.42) while the percentage improvement directly correlated with CEAP class (p = 0.033). Conclusions: The NIRS-assisted test, which is feasible in a laboratory context, objectively discriminates the hemodynamic tolerability of the treatment and identifies subjects with combined PAD and CVI with improved perfusion after CT, in spite of the presence of PAD.

Vasa - European Journal of Vascular Medicine