Muscle VO 2 and forearm blood flow repeatability during venous and arterial occlusions in healthy and coronary heart disease subjects

Abstract

This study aims were: 1) to assess forearm blood flow (FBF) and muscle oxygen consumption (mVO₂) 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 between mVO₂ calculated from NIRS signals during VO and arterial occlusion (AO) in 18 middle aged healthy subjects and 12 patients with CHD. FBF and mVO₂ were measured using NIRS during 2 successive VO (1-min duration), followed by a 5-min AO. Repeatability for FBF and mVO₂ during VO was assessed with intra class correlation (ICC), coefficient of variation (CV %) and agreement between VO and AO mVO₂ was assessed with a Bland and Altman analysis. FBF and mVO₂ during VO were highly reproducible in healthy (FBF: ICC 0.73, CV% 9.75; mVO₂: ICC 0.89, CV% 12.6) and CHD subjects (FBF: ICC 0.95, CV% 10.26; mVO₂: ICC 0.98, CV% 7.92). VO and AO mVO₂ were in agreement in healthy (mean bias: 0.002 mL O₂.min⁻¹.100g⁻¹) and CHD subjects (mean bias: 0.014 mL O₂.min⁻¹.100g⁻¹). FBF and mVO₂ measured with NIRS during VO and/or AO are highly reproducible methods to assess microvascular function in healthy subjects and stable CHD patients.