Near-infrared spectroscopy grades the severity of intermittent claudication in diabetics more accurately than ankle pressure measurement

Abstract

Background: The aim of this study was to evaluate near-infrared spectroscopy (NIRS), combined with a treadmill-walking test, as a method of assessment of intermittent claudication (IC) in diabetic patients. Methods: Some 208 symptomatic legs in 153 consecutive patients who complained of calf IC due to atherosclerotic disease were studied with NIRS and resting ankle: brachial pressure index (ABPI). Results: There was good reproducibility of NIRS measurements. Three distinct types of IC were detected by NIRS. ABPI was significantly different between these three types in non-diabetic patients, but could not grade the severity of IC in diabetic patients. Recovery time (RT) of muscle oxygenation differentiated more accurately between severe and moderate claudication than ABPI in diabetics, although RT and ABPI had similar accuracy in non-diabetics. There was a significant correlation between RT and ABPI in non-diabetic patients and patients who had been diabetic for less than 10 years, while there was no correlation in patients who had had diabetes for over 10 years. Conclusion: Measurement of muscle oxygenation during exercise by NIRS graded the severity of IC in diabetic patients more accurately than resting ABPI.