Operator Independent Endothelial Function Testing

A strong predictor for cardiovascular events

Endothelial function of the arterial vasculature is an important early marker of atherosclerosis, certainly one of the most important. While aortic pulse wave velocity (aPWV) is related to arterial elasticity of the big central arteries, endothelial function reflects the ability of the endothelial layer to release NO, modulating smooth muscle tone in the arterial wall of the conduit arteries. In diseases associated with an increased cardiovascular risk, such as diabetes or obesity, endothelial function is already compromised in early disease stages. Testing of endothelial function is a valuable tool both in the clinical setting for risk stratification and for therapy follow-up, as well as in research, drug studies in particular.

Conventional testing methods

Flow Mediated Dilation (FMD) testing, considered the Gold Standard for the evaluation of endothelial function, requires high resolution ultrasound imaging for insonation of the brachial artery over a defined period, usually around ten minutes. During insonation, the arterial blood supply to the forearm is interrupted by occluding the brachial artery with an inflated cuff. Determined from the ultrasound image, the diameter of the brachial artery is compared before and after brachial artery occlusion, and expressed as a percent change. While this modality yields reliable results in the hands of experienced researchers. Because of this demanding procedure, it is rarely applied in clinical or field testing.

EndoCheck FMS Screen Shot

Now available: Flow Mediated Slowing with VICORDER® EndoCheck FMS

Flow Mediated Slowing (FMS) testing mimics the FMD test procedure, leveraging on its underlying physiological principles. Brachial PWV is measured between the wrist and the upper arm.

While post-occlusive hyperemia leads to NO activated vessel diameter increase, pulse wave velocity (PWV) in the arm decreases. As PWV is inversely related to distensibility, a widening of brachial artery cross section will cause a drop in PWV. The coupling of acute flow-mediated relaxation of conduit artery tone with PWV reduction, or “slowing”, in the arm, independent of blood pressure, has been documented.1 In normal healthy subjects, the immediate drop from pre-occlusive PWV levels (PWV slowing or FMS) is quite significant. In patients with early or established cardiovascular disease, where endothelial function and flow-mediated vasodilation are known to be compromised, PWV slowing is markedly reduced.23

EndoCheck FMS 2 Cuffs

The EndoCheck innovation

VICORDER® has proven its competence, reliability, and user-friendliness as documented in numerous studies. A thoroughly validated testing instrument for the evaluation of arterial stiffness, VICORDER® has been expanded by this new and exciting application, VICORDER® EndoCheck FMS. Based on the ground laying evidence of the FMS coupling with endothelial function, the new VICORDER® protocol was implemented for convenient, automated, operator-independent testing of endothelial function, yielding results comparable to those of the Gold Standard FMD.


1 Naka et al. European Heart Journal. 2006

2 Ellins et al. European Journal of Preventive Cardiology. 2015

3 Cauwenberghs, et al. Artery Reasearch. 2018