Near-infrared spectroscopy and transcutaneous oxygen pressure during exercise to detect arterial ischemia at the buttock level: comparison with arteriography.

Background: Noninvasive tests are required to detect (in both male and female subjects and side by side) arteries toward the hypogastric circulation that are likely to present significant lesions as a cause of buttock claudication.

Methods: We compared the accuracy of near-infrared spectroscopy (NIRS) and transcutaneous oxygen pressure (TCP o 2 ) on both buttocks during walking tests to detect lesions on the arteries toward the hypogastric circulation. NIRS was considered abnormal if recovery time to pre-exercise values was greater than 240 seconds for tissue oxygen saturation (absent data being coded 0), and TCP o 2 was coded abnormal if the minimal value of buttock changes minus chest changes was lower than -15 mm Hg. The study was conducted in a university hospital; there were 30 ambulatory patients with stage 2 claudication of the Fontaine classification.

Results: Angiography showed 36 abnormal (stenosis > 75%) and 24 normal arterial axes toward the buttocks circulation. NIRS and TCP o 2 provided respectively 55% (range, 41.6% to 67.9%) and 82% (range, 69.6% to 90.5%) accuracy (95% confidence interval) to predict the presence of arteriographically proven lesions; P < .05.

Conclusions: Using available cut-off points proposed in the literature, NIRS showed a lower diagnostic accuracy than TCP o 2 for the prediction of lesions on the arterial tree to the hypogastric circulation. NIRS is a recent technique as compared with TCP o 2 , and its diagnostic accuracy might improve in the future. Currently, one should carefully weigh the advantages and limits of NIRS and TCP o 2 when a choice is to be made between them to monitor exercise-induced changes resulting from lower limb arterial disease at the proximal level.