Transcutaneous oxygen pressure measurements on the buttocks during exercise to detect proximal arterial ischemia: comparison with arteriography.

BACKGROUND: We sought to identify whether transcutaneous oxygen tension (tcPo2) measurements could be used to noninvasively detect lesions in the arterial network supplying blood flow to the hypogastric circulation. METHODS AND
RESULTS: A study was undertaken in vascular patients with suspected (PC, n=43) and not with suspected (NPC, n=34) proximal ischemia. TcPo2 was measured on both buttocks and with a chest reference electrode. Arteriography on the right or left side was positive for stenoses (> or =75%) or occlusion of one or more of the following arteries: the aorta, the common iliac arteries, or the internal iliac arteries. The arteriography was compared with the resting tcPo2 values (REST) and with the minimal value (MIN) and maximal change from rest normalized to eventual chest changes (DROP) recorded during or after a treadmill test. REST, MIN, and DROP were, respectively, as follows in positive versus negative arteriograms (mean+/-SD; in mm Hg): 80.2+/-10.9 versus 78.6+/-11.5 (P>0.05), 55.2+/-20.0 versus 69.9+/-15.8 (P<0.001), and -31.8+/-17.6 versus -9.5+/-6.4 (P<0.0001) in PC and 78.9+/-14.0 versus 80.5+/-14.3 (P>0.05), 64.4+/-21.0 versus 75.1+/-14.6 (P<0.02), and -24.1+/-13.5 versus -8.7+/-4.8 (P<0.0001) in NPC. In PC and NPC respectively, with a cutoff point of -16 and -15 mm Hg, DROP showed, respectively, 83%/82% and 79%/86% sensitivity/specificity in the diagnosis of positive arteriograms.
CONCLUSIONS: Proximal ischemia is a frequent finding in vascular patients. TcPo2 measurement on the buttocks during exercise is a sensitive and specific indicator for lesions in the arterial tree toward the hypogastric circulation. Potentially it could objectively assess the response to endovascular or surgical approaches to iliac lesions.