The ViperX laboratory is interested in comprehensive vascular physiology testing through the following assessments:

Flow Mediated Dilation

An assessment of endothelium dependent vasodilation, brachial artery diameter and flow will be measured under basal conditions and during reactive hyperemia following 5 minutes of an ischemic stimulus.



A measurement of arterial stiffness with an applanation tonometer. The following is measured: augmentation index (AiX), characterizing arterial pulse waves and measuring peripheral resistance and the carotid-femoral pulse wave velocity (PWV), measuring stiffness in lower-extremity arteries.


Carotid and Femoral Intima-Media Thickness 

Images and velocities of the carotid and femoral arteries can be taken by ultrasound and the thickness of the innermost two layers of the arterial wall may be measured.


Ankle Brachial Index/Toe Brachial Index


Simple, noninvasive and pain free assessment of the presence and degree of severity of PAD by measuring blood pressure at the ankle and toes.

6 Minute Walk 

A measure of walking endurance that has excellent test and re-test reliability in individuals with PAD. Following established protocol, patients walk up and down a 100-foot hallway for 6 minutes after standardized instructions to cover as much distance as possible. The distance completed at the end of 6 minutes is recorded.

All vascular physiology assessments are conducted by our trained vascular clinical team.