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

Background: The aim of this study was to evaluate near-infrared spectroscop y (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 complain ed of calf IC due to atherosclerotic disease were studied with NIRS and res ting ankle : brachial pressure index (ABPI). Results: There was good reproducibility of NIRS measurements. Three distinc t types of IC were detected by NIRS. ABPI was significantly different betwe en these three types in non-diabetic patients, but could not grade the seve rity of IC in diabetic patients. Recovery time (RT) of muscle oxygenation d ifferentiated more accurately between severe and moderate claudication than ABPI in diabetics, although RT and ABPI had similar accuracy in non-diabet ics. There was a significant correlation between RT and ABPI in non-diabeti c 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 year s. Conclusion: Measurement of muscle oxygenation during exercise by NIRS grade d the severity of IC in diabetic patients more accurately than resting ABPI .