Transcutaneous Oxygen Pressure Measurements on the Buttocks During Exercise to Detect Proximal Arterial Ischemia

Abstract

Background— We sought to identify whether transcutaneous oxygen tension (tcP o 2 ) 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. TcP o 2 was measured on both buttocks and with a chest reference electrode. Arteriography on the right or left side was positive for stenoses (≥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 tcP o 2 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. TcP o 2 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.