Radial Augmentation Index (rAI)
rAI is defined as augmented pressure as a percentage of pulse pressure. it is also determined by factors such as age and gender.
Augmentation index (Aix) measures the height of the reflected wave from the arteries, to the amplitude of the forward travelling wave of blood flow created by the coontraction of the heart, to quantify the stiffness of the artery.
Rai - (SBP2 - DBP) / SBP1 - DBP)
A Low compliance results in High RAI whereas lower numbers here indicate more elastic and pliable arteries and is associated with increased risk of coronary artery disease.
Every 10% increase in rAI represents a 28% increase in risk of MACE*
*MACE (Major Adverse Cardiac Event) includes myocardial infarction, stroke, revascularization, unstable angina and death.
Many studies have shown strong connections between arterial stiffening and CV diseases.