Resting Muscle Oxygen Consumption by Near-Infrared Spectroscopy in Peripheral Arterial Disease: A Parameter to be Considered in a Clinical Setting?

Abstract

Resting muscle VO( 2) consumption (rmVO(2)) as measured by near-infrared spectroscopy (NIRS) has been poorly studied in peripheral arterial disease (PAD). We studied the feasibility of its assessment in a clinical setting, compared values from PAD and healthy participants, and identified factors affecting rmVO( 2) in PAD. A total of 119 PAD patients with claudication and 30 healthy participants were enrolled. Ankle brachial index (ABI), adipose tissue thickness, and rmVO(2) in the gastrocnemius after venous (rmVO(2)ven) or arterial (rmVO(2)art) occlusion were measured with NIRS. Compared to rmVO(2)art, rmVO(2)ven determination was less painful (P = .001), with higher values (P < .0001). rmVO(2)ven of PAD patients was not significantly different from healthy participants and was inversely correlated with the corresponding ABI (P = .018). rmVO(2)ven from severely diseased legs was higher than values from borderline/moderately diseased legs (P = .003). The determination of rmVO(2)ven by NIRS is suitable for the clinical setting and allows noninvasive quantification of a compensatory peripheral adaptation in patients with PAD.

The Role of Deconditioning in the End-Stage Renal Disease Myopathy: Physical Exercise Improves Altered Resting Muscle Oxygen Consumption

“…It was recommended that biomarkers of muscle function related to clinical status be tested and applied to develop biological models of recovery in severe, disabling diseases like stroke [31] . Findings in this study in ESRD patients and observations on other chronic conditions [5,6] concur in supporting rmVO 2 as a biomarker of peripheral deconditioning in ESRD patients. In this study, we document that rmVO 2 is not a mere surrogate of other risk factors or disease markers.…”

“…Along with our working hypothesis, we found that rmVO 2 in resting condition was much higher in ESRD patients than in coeval healthy subjects. Of note, rmVO 2 in these patients (0.083 ± 0.034 ml/100 g/min) was also higher than that we had previously observedunder the same experimental conditions and with the same NIRS device -in patients with peripheral artery disease (0.069 ml/100 g/min) [5] and in those with multiple sclerosis (0.059 ml/100 g/min) [6] . The increased muscle oxygen consumption in ESRD patients was un- Paired sample t-test (* p < 0.05).…”

“…Therefore, studies investigating the reversibility of ESRD myopathy are important to inform clinical trials testing the effect of physical exercise programs in ESRD. Along with observations made in other chronic conditions [5,6] and considering the potential benefits of exercise on this population [28], we hypothesized that an exercise program may induce a measurable improvement in the myopathy of ESRD patients. In this study, we document for the first time that physical training in these patients produces a parallel improvement in physical performance (as measured by the 6MWD) and in rmVO 2 .…”

“…NIRS measurement to determine the rmVO 2 was made at the level of skinfold measurement, along the medial gastrocnemius muscle as detailed elsewhere [5] . The distance between the NIRS sensor and malleolus medialis was measured and recorded for each patient to maintain the correct positioning at 6 months follow-up evaluation.…”

“…Resting muscle oxygen consumption (rmVO 2 ), a parameter which quantifies muscle's capacity to extract oxygen from the blood in standardized conditions, can be measured noninvasively by near-infrared spectroscopy (NIRS) [4] . rmVO 2 is markedly increased in ischemic muscles in patients with peripheral artery disease [5] or in deconditioned patients with disabling chronic diseases like multiple sclerosis [6] . rmVO 2 reflects a fundamental biological function of the skeletal muscle and therefore may represent a biomarker, which can be applied to quantify the severity of myopathy and its reversibility in the ESRD population.…”