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

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. 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. 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. 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.