Harnessing Biomimicry

Professor Caro’s research was first published in Nature in 1969 and demonstrated that there is a correlation between regions of low wall shear and the occurrence of atheroma.2,3 His later research developed this further and demonstrated that non-planar, three dimensional curvature present in the human vascular system generates secondary flow, elevates wall shear and may confer a vasoprotective effect.4 This research has been corroborated by other investigators. 5–7

Veryan has developed and patented a three dimensional (3D) stent technology based upon a helical shape that may be applied to a self-expanding stent platform. The objective of Veryan’s proprietary technology is to improve the biomechanical and flow characteristics of straight tubular stents. The focus to date has been on the superficial femoral and proximal popliteal (femoropopliteal) arteries. Existing stents indicated for placement in the femoropopliteal artery have a straight tubular design and therefore tend to straighten any curvature present in vessels. This straightening effect may interfere with normal shortening of the femoropopliteal artery during lower limb movement. In addition, fracture of Nitinol stents has been reported in the femoropopliteal application. It is the inherent shortcomings of straight tubular stents that are driving Veryan’s development of BioMimics 3D™ technology.

In particular, Veryan has applied this technology to its proprietary stent platform to create the BioMimics 3D self-expanding Nitinol stent (see image) for use in the treatment of patients with peripheral arterial disease requiring endovascular intervention to relieve obstruction or occlusion of the femoropopliteal artery. The design of the BioMimics 3D stent is built on the principles underlying the latest generation of Nitinol stent technology - adequate mechanical radial support and plaque coverage, good flexibility, durability against fracture, clear visualisation and delivery accuracy - with the addition of the biomechanical and flow characteristics arising from the 3D geometry.

BioMimics

2. Caro, C. G., Fitz-Gerald, J. M. & Schroter, R. C. Arterial Wall Shear and Distribution of Early Atheroma in Man. Nature 223, 1159–1161 (1969).
3. Caro, C. G., Fitz-Gerald, J. M. & Schroter, R. C. Atheroma and Arterial Wall Shear Observation, Correlation and Proposal of a Shear Dependent Mass Transfer Mechanism for Atherogenesis. Proceedings of the Royal Society B: Biological Sciences 177, 109–133 (1971).
4. Caro, C. G. et al. Non-Planar Curvature and Branching of Arteries and Non-Planar-Type Flow. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 452, 185–197 (1996).
5. Zarins, C. K. et al. Carotid bifurcation atherosclerosis. Quantitative correlation of plaque localization with flow velocity profiles and wall shear stress. Circ Res 53, 502–14 (1983).
6. Friedman, M. H., Hutchins, G. M., Bargeron, C. B., Deters, O. J. & Mark, F. F. Correlation of human arterial morphology with hemodynamic measurements in arterial casts. J Biomech Eng 103, 204–207 (1981).
7. Carlier, S. G. et al. Augmentation of wall shear stress inhibits neointimal hyperplasia after stent implantation: inhibition through reduction of inflammation? Circulation 107, 2741–6 (2003).