Background: In addition to measurement of diameter, intima-media thickness (IMT) and stiffness, the high resolution of non-invasive echotracking systems (Wall Track System^® ArtLab^®) permits to have insights in new parameters. First we can study longitudinal segmental inhomogeneities of strain defining gradients of strain and layer-by-layer changes in strain within the arterial wall, defining inhomogeneities in compressibility. The aim of the present report is to present feasibility data and first results for these two parameters.

Methods and results: Multidirectional segmentations of radio-frequency matrix recordings were applied to different diseases. First, longitudinal gradient of strain were measured in 92 patients with plaques, either hypertensive or not. Second, strain gradient within the wall (hence estimated compressibility), was tested in 46 patients with vascular Ehlers-Danlos Syndrome (vEDS) and 72 controls. Different conceptual and operational tools were developed under Matlab^® software for these purposes. We observed that remodeling at the level of the plaque deeply influenced the segmental behavior of strain, inward remodeling being associated with exaggerated strain, and outward remodeling with reduced strain. We showed that both vEDS and control subjects exhibited marked excess of compressibility within IMT, and that this highly compressible zone was closer to the lumen and accentuated in vEDS than in controls.

Conclusion: It is possible to make segmental analysis of segmental properties of remodelling and bending stress. In addition, apparently homogeneous arterial walls exhibited mechanical interfaces which exaggerated compressibility and local stresses between different sub-layers within the wall.