Exercise transcutaneous oxygen pressure measurement has good sensitivity and specificity to detect lower extremity arterial stenosis assessed by computed tomography angiography

Abstract

Peripheral artery disease (PAD) is a highly prevalent disease diagnosed by the use of ankle-brachial index (ABI) at rest. In some clinical conditions (diabetes, renal insufficiency, advanced age), ABI can be falsely normal and other tests are required for the PAD diagnosis (American Heart Association statement). This study was conducted to determine the accuracy of exercise transcutaneous oxygen pressure measurement (exercise-TcPo2) in detection of arterial stenosis ≥50% using computed tomography angiography (CTA) as the gold standard.We retrospectively analyzed consecutive patients referred to our vascular unit (University Hospital, Rennes, France) for exercise-TcPo2 testing from 2014 to 2015. All included patients had a CTA performed within 3 months of the exercise-TcPo2 test. Exercise-TcPo2 was performed on treadmill (10% slope; 2 mph speed). We calculated the Delta from Resting Oxygen Pressure (DROP) index (expressed in mm Hg) at the proximal and distal levels. Two blinded physicians performed stenosis quantification on CTA. The receiver operating characteristic (ROC) curve was used to define a cutoff point to detect arterial stenosis ≥50%, stenosis ≥60%, and stenosis ≥70%.A total of 34 patients (mean age 64 ± 2 years old; 74% men) were analyzed. The highest areas under the curve (AUC) were found for 60% stenosis at both proximal and distal levels. For stenosis ≥50%, sensitivity and specificity of proximal minimal DROP were 80.9% [67.1–89.7], 81.0% [59.3–92.7] respectively. For stenosis ≥50%, sensitivity and specificity of distal minimal DROP were 73.2% [60.3–83.1], 83.3% [53.8–96.2], respectively. For stenosis ≥60%, sensitivity and specificity of proximal minimal DROP were 82.5% [67.6–91.5] and 85.7% [67.7–94.8] respectively. For stenosis ≥60%, sensitivity and specificity of distal minimal DROP were 80.4% [67.3–89.1] and 88.2% [64.2–97.7], respectively. For stenosis ≥70%, sensitivity and specificity of proximal minimal DROP were 85.7% [67.7–94.8] and 75.0% [59.6–85.9] respectively. For stenosis ≥70%, sensitivity and specificity of distal minimal DROP were 86.0% [72.2–93.7] and 76.0% [56.1–88.7], respectively.Exercise-TcPo2 using a proximal minimal DROP value ≤−15 mm Hg or a distal minimal DROP value ≤−16 mm Hg is accurate to diagnose arterial stenosis especially stenosis ≥60% on the lower limbs. Exercise-TcPo2 is safe and noninvasive test that might be used in second line for PAD diagnosis.

Exercise Ischemia Induced by Essential Thrombocytemia Diagnosed on Treadmill Test ― Transcutaneous Oxygen Pressure Measurement of Foot Ischemia ―

“…In the right and left calves, DROPmin was always above −16 mmHg; in the right and left buttocks it was always above −15 mmHg. 2 The MWT was 1,204 s, corresponding to an MWD of 1,053 m, and walking was stopped at the end of the treadmill test. Exercise-tcpO2 confirmed exerciseinduced left foot ischemia.…”

“…2 A reference probe (chest probe) was placed between the scapulae to measure systemic changes in tcpO2 during exercise. 2 One probe was positioned on each buttock and one probe on each calf. Once the probes were in position, the patient then waited for 10 min in the standing position, in order to stabilize the probes to obtain baseline values.…”

“…We have already shown its usefulness in the diagnosis and monitoring of peripheral arterial disease (PAD) and exercise claudication. 2 …”

Exercise Transcutaneous Oximetry of the Buttocks, External Validation With Computed Tomography Angiography

“…Finally, we would like to add that this technique is also of interest for the assessment of distal claudication (in the calf), especially for patients who have incompressible arteries or a neuropathy where it is difficult to conclude that the pain has a vascular origin. 2 We read with great interest the paper from Audonnet et al about the accuracy of exercise transcutaneous oximetry (Ex-tcPO2) of the buttocks to detect stenosis greater than 75% in arteries towards the pelvic circulation. 1 In our study in 2016 we used computed tomography angiography (CTA) as the gold standard.…”

“…1 In our study in 2016 we used computed tomography angiography (CTA) as the gold standard. 2 We tested the accuracy of Ex-tcPO2 to detect different levels of arterial stenosis of the lower limbs (≥50%, ≥60%, and ≥70%) using a similar methodology. Of interest, we found quite similar results for the detection of stenosis ≥70%.…”