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Introduction: We have previously described three distinct cutaneous microvascular responses to an ischaemic stimulus using laser Dopplerfluximetry (Strain et al., 2005). These are associated with a gradation of cardiovascular risk. 1) "normal response" with a controlled graded rise to peak at ~ 10-15 seconds, 2) "non-dominant early peak (NDEP)," with an abnormal early peak within 2 seconds of lower amplitude than the subsequent "normal" graded rise to peak, 3) "dominant early peak (DEP)" within 2 seconds of cuff release with maximum amplitude, which declines rapidly and is then followed by a lesser "normal" peak. Exact mechanism involved in abnormal peak responses are unclear, however we believe it represents a proxy for systemic microvascular (MV) regulatory disturbance. Aims: To explore associations between microvascular regulatory responses and cutaneous blood oxygenation (SO2, %). Methods: Post occlusive reactive hyperaemia of the micro-circulation was assessed on the foot of participants with cardiovascular disease (CVD), diabetes (DM), both (DM+CVD) or neither (controls) using laser Dopplerfluximetry and Oxygen to See, which measures blood oxygen saturation in the first 1 mm of skin. All participants underwent basic demographic & biochemical screening. Results: 232 participants were studied, 76 controls, 106 with CVD, 34 with DM and 16 with DM+CVD. Results were stratified by peak response groups. In keeping with previous reports, there was an increase in CVD, diabetes and CVD risk factors across peak response groups (Table 1). Area under the curve (AUC) of oxygen saturation was incrementally lower in those with impaired autoregulation. After adjustment for CVD, diabetes, blood pressure, heart rate and BMI, this remained strongly negatively associated with abnormal peak responses, geometric mean (95% CI) normal 1459(1364-1554) vs. NDEP 1212(1132-1292) (p=0.001) vs. DEP 1142(1040-1245) (p<0.001). Conclusion: These data suggest that the previously described abnormal peak responses have significant consequences in the delivery of oxygen as they are independently associated with reduced mean oxygen saturation post ischaemia. [ABSTRACT FROM AUTHOR]