Changes in vascular responsiveness during a hyperglycemia challenge measured by near-infrared spectroscopy vascular occlusion test.

ABSTRACT

BACKGROUND: Postprandial hyperglycemia is associated with impaired vascular responsiveness. Recent studies have established the use of a near-infrared spectroscopy (NIRS)-derived approach, combined with a vascular occlusion test (VOT), to examine vascular responsiveness within the microvasculature in normoglycemia. The aim of this study was to examine whether this NIRS-VOT technique could detect differences in vascular responsiveness following a hyperglycemic challenge. METHODS AND RESULTS: Fourteen young healthy individuals participated in the study. Participants underwent five vascular occlusion tests (pre, 30, 60, 90 and 120min after glucose ingestion). Vascular responsiveness was determined by the slope 2 of oxygen saturation (Slope 2 StO2) and the area under the curve of oxygen saturation (StO2AUC) signal. All individuals had a significant increase in blood glucose concentration after 30min (p<0.001), 60min (p<0.001) and 90min (p<0.01) after glucose ingestion. The Slope 2 StO2 increased at 90min (p<0.01) after glucose ingestion. Conversely, The StO2AUC was significantly decreased 90min following the glucose challenge (p<0.01). A negative correlation was observed between average StO2AUC and average Slope 2 StO2 (r=-0.995; p<0.05). CONCLUSION: This study showed that the NIRS-VOT technique is capable of detecting differential changes in vascular responsiveness to a hyperglycemic challenge, as indicated by a steeper Slope 2 StO2 and decreased StO2AUC following 90min of an oral glucose challenge.