Professor Caro in his paper in Nature 19691 proposed that regions of low wall-shear rate in the human arterial system predispose to the development of atheroma. This highly significant discovery subsequently contributed to the understanding that post-interventional neointimal hyperplasia also preferentially affects low wall shear regions caused by flow disturbance.
A fundamental characteristic of the body’s arterial system is non-planar geometry and the 3D vascular curvature inherent in non-planarity is an important factor influencing arterial flows, including the elevation of protective wall shear.
Veryan has designed the BioMimics 3D Nitinol, self-expanding stent technology to not only harness flow-mediated benefits through its biomimicry of arterial three dimensional geometry, compared to straight Nitinol stents that impose planar geometry on the stented segment, but also to provide superior biomechanical performance.
Veryan started with three objectives when designing the BioMimics 3D stent for femoropoliteal intervention:
- to promote swirling blood flow and increase wall shear in the stented arterial segment;
- to improve biomechanical compatibility and reduce vascular irritation and injury, and;
- to reduce the risk of stent fracture, particularly in long stents.
The BioMimics 3D Nitinol stent design is based on a helical shape that closely mimics the natural geometry of the human vascular system and enables the stented segment to shorten under compression. The 3D stent imparts a gentle helical shape to the stented artery, provoking a swirling flow-mediated increase in wall shear stress that has been shown to reduce intimal hyperplasia. Mechanical performance of the stent is improved by allowing shortening and bending strains to be distributed across the entire 3D stent geometry, in contrast to strains that become highly localised in a straight stent, risking fracture especially in longer stents.
1 Caro CG, Fitz-Gerald JM, Schroter RC. Arterial wall shear and distribution of early atheroma in man. Nature. 1969;223:1159 –1160.