Exercise testing criteria to diagnose lower extremity peripheral artery disease assessed by computed-tomography angiography

Abstract

Background The sensitivity and specificity of exercise testing have never been studied simultaneously against an objective quantification of arterial stenosis. Aims were to define the sensitivity and specificity of several exercise tests to detect peripheral artery disease (PAD), and to assess whether or not defined criteria defined in patients suspected of having a PAD show a difference dependent on the resting ABI. Methods In this prospective study, consecutive patients with exertional limb pain referred to our vascular center were included. All patients had an ABI, a treadmill exercise-oximetry test, a second treadmill test (both 10% slope; 3.2km/h speed) with post-exercise pressures, and a computed-tomography-angiography (CTA). The receiver-operating-characteristic curve was used to define a cut-off point corresponding to the best area under the curve (AUC; [CI95%]) to detect arterial stenosis ≥50% as determined by the CTA. Results Sixty-three patients (61+/-11 years-old) were included. Similar AUCs from 0.72[0.63–0.79] to 0.83[0.75–0.89] were found for the different tests in the overall population. To detect arterial stenosis ≥50%, cut-off values of ABI, post-exercise ABI, post-exercise ABI decrease, post-exercise ankle pressure decrease, and distal delta from rest oxygen pressure (DROP) index were ≤0.91, ≤0.52, ≥43%, ≥20mmHg and ≤-15mmHg, respectively (p<0.01). In the subset of patients with an ABI >0.91, cut-off values of post-exercise ABI decrease (AUC = 0.67[0.53–0.78]), and DROP (AUC = 0.67[0.53–0.78]) were ≥18.5%, and ≤-15mmHg respectively (p<0.05). Conclusion Resting ABI is as accurate as exercise testing in patients with exertional limb pain. Specific exercise testing cut-off values should be used in patients with normal ABI to diagnose PAD.

Confirmation of discrepancies between exercise oximetry and American Heart Association post-exercise criteria to diagnose peripheral artery disease in patients with normal ankle-brachial index at rest

“…We conducted a similar study comparing exercise oximetry with post-exercise AHA tests. The validation of the AHA post-exercise criteria (post-exercise ABI decrease > 20% and/or post-exercise ankle pressure decrease > 30 mmHg) are discussed [6,9]. However, as Abraham and colleagues compared their results with AHA criteria [1], we also performed a similar analysis in order to see if we would obtain comparable results.…”

“…We included 96 consecutive patients with exertional limb symptoms and normal ABI at rest (versus 82 for Abraham et al) in the exercise PAD study that was registered with the American National Institutes of Health database under reference n°NCT03186391. The methodology of our study has been previously described [9]. In brief, patients had ABI measurement, exercise oximetry and post-exercise pressure measurements on a same appointment to allow for comparisons between tests.…”

“…In brief, patients had ABI measurement, exercise oximetry and post-exercise pressure measurements on a same appointment to allow for comparisons between tests. ABI and post-exercise pressures were measured using hand-held Doppler for leg pressures and with an automatic device (Carescape™ Dinamap V100; GE Healthcare) for brachial pressures [8,9]. Exercise oximetry was performed as previously described by using validated in-house free software (Oxymonitor; https://imagemed.univ-rennes1.fr/en/oxymonitor/download.php) [5,7].…”

“…For the statistical analyses, we analysed the concordance between exercise oximetry and post-exercise pressure decrease and post-exercise ABI decrease measured on the most symptomatic leg by using the Kappa coefficient with a confidence interval of 95% [4]. Post-exercise ABI decrease > 20%, post-exercise ankle pressure decrease > 30 mmHg and delta from rest of oxygen pressure (DROP) value equal or greater than − 15 mmHg were considered as diagnosis for PAD as previously validated [2,3,6,9].…”

“…Our results strengthen the results from Abraham and colleagues confirming that exercise tests are not equivalent. Our study has several major points of interest: 1) only patients with exertional limb symptoms and normal ABI were included, as recommended by the AHA algorithm for PAD diagnosis; 2) we used validated methodology to record ABI at rest, postexercise ankle pressure [9]; 3) to reduce latency between end of exercise and measurement, post-exercise pressures were measured first on the symptomatic leg and the artery to perform the measurement was identified at rest as previously suggested [8]. One limitation of our study compared with Abraham et al study is that the order of exercise oximetry and exercise pressure measurement was not randomized; however, a 15-min rest period was observed between the two tests.…”