Table 1.

Methods to assess arterial stiffness.

Carotid-Femoral Pulse Wave Velocity (cfPWV)	Gold-standard method.
Brachial-Ankle Pulse Wave Velocity (baPWV)	baPWV was calculated as: Distance (meters)/Δt (seconds).
Augmentation Index (AI)	Assessed by Applanation Tonometry.The augmentation pressure (AG) is the measure of contribution that the wave reflection makes to the systolic arterial pressure, and it is obtained by measuring the reflected wave coming from the peripheral to the central arteries.
Cardio-Ankle Vascular Index (CAVI)	CAVI is an index obtained by recording the distance from the level of the aortic valve (i.e., brachial level) to the measuring point (i.e., the ankle) and the time delay between the closing of the aortic valve to the detected change in arterial pressure wave at the set point. Information for CAVI computation, including PWV, systolic and diastolic blood pressure as well as arterial pulse waveforms, can then be acquired through the electrocardiogram, cardiac phonogram, and the pressure cuffs on the testing subject at the reference points.Thought to be or claimed to be blood pressure independent.
QKDh	The QKd interval is the time (measured in milliseconds) between the onset of depolarization on electrocardiography (Q) and detection of the last Korotkoff sound (K) at the brachial artery during cuff deflation, corresponding to the diastolic blood pressure (d). This interval is inversely correlated with pulse wave velocity.
β Index	Stiffness Index Beta is derived from PWV, PP, SBP, DBP and viscosity and was calculated by an equation.Thought to be or claimed to be blood pressure independent
Ambulatory Arterial Stiffness Index (AASI)	The Ambulatory Arterial Stiffness Index (AASI) is an indirect arterial stiffness index, which can be simply calculated from 24-h Ambulatory Blood Pressure Monitoring (ABPM).