Augmentation index

Method

Augmentation index derived from radial or aortic pulse wave analysis by applanation tonometry, expressed as augmented pressure as a percentage of pulse pressure. Whether the value was normalised to a heart rate of 75 beats per minute, and whether the waveform was radial or aortic, are recorded on the edge.

The method is part of the endpoint identity. Studies measuring the same quantity by a different method are held as separate endpoints.

Notes

SIGN INVERSION against CAT:outcome/flow-mediated-dilation. Both are vascular-function endpoints expressed as PERCENTAGES from the same study visit and often the same paragraph, but this improves by FALLING (less wave reflection, more compliant vessels) while flow-mediated dilation improves by RISING. Distinct also from pulse wave velocity and carotid-femoral pulse wave velocity, obtained in the same tonometry session but reported in m/s and measuring stiffness directly rather than reflection timing. Heart-rate dependence is strong, which is why the normalisation flag is not optional.