Vascular function testing was conducted after 5 minutes of rest in the supine position. Three measures of brachial artery distensibility (BrachD), systolic (SBP), diastolic (DBP), mean arterial blood pressures (MAP), pulse pressure (PP) and heart rate (HR) were obtained with a DynaPulse Pathway instrument (Pulse Metric, Inc., San Diego, CA) as previously described.[11 (link)] This device derives brachial artery pressure curves from distensibility arterial pressure signals obtained from a standard cuff sphygmomanometer assuming a straight tube brachial artery and T-tube aortic system.[11 (link)] Repeat measures in our laboratory show excellent reproducibility with coefficients of variability less than 9% (unpublished data).
Pulse Wave Velocity (PWV) was measured with a SphygmoCor SCOR-PVx System (Atcor Medical, Sydney, Australia) according to the manufacturer's protocol. The average of three recordings of PWV for each of the arterial sites: PWV-arm (carotid-radial); PWV-trunk (carotid-femoral) and PWV-leg (femoral-foot) was used in the analyses. Repeat measures in our laboratory show excellent reproducibility with coefficients of variability less than 7% (unpublished data).
Augmentation Index (AIx), which is influenced by arterial stiffness and provides additional information concerning wave reflections[12 (link)] was also collected. The SphygmoCor tonometer was placed over the right radial artery and 3 measures of AIx were collected. The pressure waves were calibrated using MAP and DBP obtained in the same arm. The device then analyzed the pulse wave using a validated generalized transfer function.[13 (link)] Since AIx is affected by HR, values were adjusted to a standard HR of 75 beats per minute. Reproducibility studies in our laboratory demonstrated intraclass correlation coefficients between 0.7 and 0.9 for all variables (unpublished data).
Pulse Wave Velocity (PWV) was measured with a SphygmoCor SCOR-PVx System (Atcor Medical, Sydney, Australia) according to the manufacturer's protocol. The average of three recordings of PWV for each of the arterial sites: PWV-arm (carotid-radial); PWV-trunk (carotid-femoral) and PWV-leg (femoral-foot) was used in the analyses. Repeat measures in our laboratory show excellent reproducibility with coefficients of variability less than 7% (unpublished data).
Augmentation Index (AIx), which is influenced by arterial stiffness and provides additional information concerning wave reflections[12 (link)] was also collected. The SphygmoCor tonometer was placed over the right radial artery and 3 measures of AIx were collected. The pressure waves were calibrated using MAP and DBP obtained in the same arm. The device then analyzed the pulse wave using a validated generalized transfer function.[13 (link)] Since AIx is affected by HR, values were adjusted to a standard HR of 75 beats per minute. Reproducibility studies in our laboratory demonstrated intraclass correlation coefficients between 0.7 and 0.9 for all variables (unpublished data).
