Reduction in Restenosis
Straight stents tend to exacerbate poor flow conditions that may occur in an atherosclerotic, femoropopliteal artery. Professor Caro, in his paper in Nature 1969 and further developed in his subsequent publications, demonstrated that the human vasculature has a predominantly non-planar, three dimensional curvature that generates secondary or swirling flow, elevating wall shear stress (the frictional drag on the endothelium from blood flow,) which may confer a vasoprotective effect. Almost 4,000 publications related to wall shear stress have been published since, and the evidence shows that atherosclerosis and arterial wall thickening occur where sections of the wall are subject to low shear forces. Veryan believes that arterial straightening and reduced shear stress may be important contributors to adverse clinical outcomes in femoropopliteal stenting. Veryan’s preclinical program provided confirmatory evidence of the potential benefit of swirling flow generated by a stent with 3D helical geometry. A controlled study (see below) was conducted in a porcine carotid model to compare the effects in arteries implanted with 3D helical stents compared to the same stent without 3D geometry as the control. A 45% reduction (P<0.001) in neointimal thickness was demonstrated in 3D-stented compared to straight-stented arteries, confirming the protective effect.