Tissue oxygen partial pressure in the tibialis anterior muscle in patients with claudication before,during and after a two-stage treadmill stress test

BACKGROUND: The role of the microcirculation in the pathophysiology and symptoms of peripheral arterial obliterative disease (PAOD) has been progressively emphasized during the past decades. Under resting conditions, already, the tissue oxygen partial pressure in the m. tibialis anterior (pO2_im) is reduced to about 50% compared to healthy subjects.

METHODS: In the framework of this study the pO2_im of patients with PAOD stage II according to Fontaine (n=16) in the m. tibialis anterior was measured under resting conditions and during walking on a treadmill in comparison to healthy subjects (n=10).

RESULTS: Under resting conditions the pO2_im only marginally differed between PAOD patients and healthy subjects. But during exercise the pO2_im dropped significantly more severely in PAOD patients and a return to baseline values could only be reached when the treadmill was stopped and the patients stood still. The pO2_im minima correlated clearly with the clinical symptom of calf pain.

CONCLUSION: The data revealed that the pO2_im values were lower in PAOD patients and dropped significantly faster during walking compared to the pO2_im values in healthy subjects. The pO2_im decrease correlated with the calf pain occurring when the pO2_im values approached or fell below 10 mmHg.