Muscle VO2 and forearm blood flow repeatability during venous and arterial occlusions in healthy and coronary heart disease subjects

This study aims were: 1) to assess forearm blood flow (FBF) and muscle oxygen consumption (mVO(2)) repeatability assessed with near-infra red spectroscopy (NIRS) during venous occlusions (VO) in middle aged healthy subjects and patients with stable coronary heart disease (CHD), 2) to assess the agreement betweenmVO(2) calculated from NIRS signals duringVOand arterial occlusion (AO) in 18 middle aged healthy subjects and 12 patients with CHD. FBF andmVO(2) were measured using NIRS during 2 successive VO (1-min duration), followed by a 5-min AO. Repeatability for FBF and mVO(2) during VO was assessed with intra class correlation (ICC), coefficient of variation (CV %) and agreement between VO and AOmVO(2) was assessed with a Bland and Altman analysis. FBF and mVO(2) during VO were highly reproducible in healthy (FBF: ICC 0.73, CV% 9.75; mVO(2): ICC 0.89, CV% 12.6) and CHD subjects (FBF: ICC 0.95, CV% 10.26; mVO(2): ICC 0.98, CV% 7.92). VO and AO mVO(2) were in agreement in healthy (mean bias: 0.002mL O-2.min(-1).100g(-1)) and CHD subjects (mean bias: 0.014mL O-2.min(-1).100g(-1)). FBF and mVO(2) measured with NIRS during VO and/or AO are highly reproducible methods to assess microvascular function in healthy subjects and stable CHD patients.