Data presented during a late breaking clinical trials session at VIVA13 show that a stent with three dimensional helical geometry, BioMimics 3D (Veryan Medical), have demonstrated safety and promising clinical performance at 12 months in the treatment of patients with peripheral arterial disease undergoing femoropopliteal artery intervention.
The MIMICS study is a prospective, 2:1 randomised controlled trial, conducted at eight German investigational centres, comparing the safety and efficacy of the BioMimics 3D stent to a straight nitinol stent (primarily the Bard LifeStent) in 76 patients with peripheral arterial disease undergoing femoropopliteal artery intervention.
The BioMimics 3D stent features unique 3D geometric curvature that closely mimics the natural helical geometry of the human vascular system. This stent is designed to promote swirling blood flow through the stented segment, which preclinical data have shown to significantly reduce the formation of neointimal hyperplasia, potentially conferring a vasoprotective effect through elevation of wall shear stress.
Data presented by principal investigator Thomas Zeller, Universitäts-Herzzentrum, Freiburg-Bad Krozingen, Germany, on behalf of the MIMICS investigators showed the 12-month Kaplan Meier estimate of freedom from clinically driven target lesion revascularisation for subjects receiving the BioMimics 3D stent was 91.2%. The Kaplan Meier estimate of 12-month primary patency was 80.4% for BioMimics 3D subjects vs. 72.0% for the control group (day 365; p=0.436). No stent fractures were detected by core lab in BioMimics 3D or Control in 12-month X-rays. Twelve-month data from the MIMICS study point to a correlation between primary patency and stent curvature, measured using bi-planar X-ray imaging in straight and bent knee positions. No loss of stent patency was observed in any subject where stent curvature measured >0.02mm. Bi-planar X-ray imaging and computational fluid dynamic modelling showed increases in both swirling flow (55%, p=0.017) and wall shear stress (18%, p=0.054) for BioMimics 3D compared to Control. Interim 24-month data show that 76% of BioMimics 3D subjects gained a PSVR improvement between 12 and 24 months, which is 83% more than control (p=0.067). Twenty-four month follow-up assessments are ongoing.
These data provide support for the hypothesis that a stent with 3D geometric curvature will be patency-protective through development of swirling flow and elevation of wall shear stress. The helical geometry of the BioMimics 3D stent also enhances mechanical performance and biomechanical compatibility, intended to reduce stent fracture, vessel and stent kinking, deformation and subsequent vessel trauma during leg flexion, compared to straight nitinol stents.
“Data on the BioMimics 3D stent demonstrating promotion of swirling flow and increased wall shear stress, together with 12-month and emerging 24-month patency data, point to the merit of this innovative approach to stent design for femoropopliteal use,” said Zeller. “We now need additional longer-term data to confirm these effects”.
Veryan received CE mark approval for the BioMimics 3D stent in November 2012.