augmentation index
Also written as: AIx — Augmentation Index
A measure of arterial stiffness calculated from pulse wave analysis, expressed as a percentage.
Full Definition
The augmentation index is a non-invasive measure of arterial stiffness derived from pulse wave analysis. It represents the additional pressure imposed on the heart by early return of reflected pulse waves from the periphery. Calculated as the difference between the second and first systolic peaks divided by pulse pressure, expressed as a percentage. Higher values indicate greater arterial stiffness and increased cardiovascular risk. The measurement is heart rate-dependent and often normalized to a heart rate of 75 beats per minute.
Usage
Usage note: Often abbreviated as AIx; ensure heart rate normalization is specified when reporting values.
In Context
- "The patient's augmentation index of 35% suggested significant arterial stiffening for her age." — vascular assessment report
- "Augmentation index improved following six months of aerobic exercise training." — preventive cardiology follow-up