Title : Transcutaneous oximetry in patients with intermittent claudication caused by occlusive and stenotic lesions of the main arteries of the lower limbs

Background: The ankle-brachial index (ABI) is the standard non-invasive test for lower limb ischemia; however, it reflects macrohemodynamics and does not directly assess tissue perfusion. Transcutaneous oximetry (tcpO2) evaluates the oxygen supply of the skin, but its diagnostic value during exercise testing in patients with intermittent claudication remains insufficiently studied.

Aim: To evaluate the correlation between tcpO2 on the feet during an exercise test and ABI values in patients with occlusive and stenotic lesions of the main arteries of the lower limbs.

Methods: The retrospective study included 34 patients with occlusive and stenotic lesions of the lower limb arteries. All patients underwent measurement of ankle and brachial pressure using a Vivid 7 ultrasound system (General Electric, USA), followed by calculation of the ABI. The exercise test was performed on a motorized treadmill at a speed of 3 km/h and an incline of 10°. TcpO2 was recorded on the dorsal surfaces of both feet every 20 seconds in the supine, sitting and standing positions, then during walking and after its cessation. The test was terminated at the patient's request upon the onset or worsening of claudication pain that prevented further testing. The correlation between the minimum absolute tcpO2 values on the feet, as well as their ratios at different measurement periods, and the ABI was assessed.

Results: No statistically significant correlation was found between absolute tcpO2 values on the feet and the ABI. However, a positive correlation was revealed between the ABI and the ratio of tcpO2 in the recovery period after exercise to the baseline tcpO2 in the standing position (rho = 0.48; p = 0.001). A ratio ≤0.84 had a sensitivity of 70% and a specificity of 88% for an ABI <0.7 (p<0.001).

Conclusions: Transcutaneous oximetry of the feet during an exercise test can be used for the diagnosis of chronic lower limb ischemia. A ratio of tcpO2 on the feet in the recovery period after exercise to the corresponding value at rest in the standing position of ≤0.84 may indicate subcompensated lower limb ischemia.

To be updated shortly..