The BioMimics 3D (Veryan Medical) helical swirling flow stent system provides an alternative to antiproliferative drugs, according to one-year data from the MIMICS-2 trial. The results were presented at Leipzig Interventional Course (LINC; 30 January–2 February 2018, Leipzig, Germany) by Thomas Zeller from the Universitäts-Herzzentrum Freiburg in Bad Krozingen, Germany.
The MIMICS-2 trial is investigating the safety and effectiveness of the BioMimics 3D stent, a helical, swirling flow stent system for treatment of symptomatic atherosclerotic disease in the femoropopliteal artery. It is a single-arm, prospective, multinational study with a planned three years of follow-up, and follows the initial MIMICS randomised controlled (RCT) CE trial in comparing Varyan Medical’s helical stent with traditional straight stents. MIMICS-2 enrolled 271 patients undergoing femoropopliteal intervention across 43 sites in the USA, Japan and Germany, conducted under a US FDA investigational device exemption with concurrence of the Japanese Pharmaceuticals and Medical Devices Agency.
The hypothesis behind the helical design of the stent is that in mimicking the natural anatomical conditions of the vessel system, a natural swirling flow can be achieved. In the human body, Zeller explained at LINC, vessel structures are “characterised by a lot of curvatures, which do induce a so-called swirling flow—onward and backward flow in different areas, increasing the wall shear stress. This increased wall shear stress has been shown to be protective against stenosis and restenosis development.” Varyan Medical also states that the shape of the stent is designed to facilitate shortening of the stented segment during knee flexion and mitigate the risk of stented segment compression causing localised strains that in a straight stent may lead to stent fracture and chronic vascular injury.
Highlighting the lesion characteristics in the MIMICS-2 patient cohort (n=271), Zeller noted that all lesions treated had been de novo, with a mean diameter stenosis of 77.8% (±18.3%), and moderate to severe stenosis was found in 45.9%. The mean lesion length was around 8cm (8.12±3.84), with a slightly longer stented segment length at a mean of 11.23cm (±3.63cm). Technical success was 100%.
Zeller announced that the trials primary safety and effectiveness endpoints were both met, and there had been no stent fractures. Primary patency at one year was 81.9% and the Kaplan-Meier estimate of freedom from clinically driven target lesion revascularisation was 88.4%. Safety had been defined as freedom from major adverse events through 30 days, including death, target limb major amputation, or clinically driven target lesion revascularisation. The safety composite performance goal of >88% was “clearly achieved with 99.6%,”, Zeller said, adding “There was one target lesion revascularisation within 30 days due to an acute stent thrombosis”.
“The probability of freedom from loss of primary patency at one year with BioMimics 3D was similar to those seen with drug-eluting stents and drug-coated balloons. Natural swirling flow is an alternative to antiproliferative drugs”, Zeller said in his concluding comments. “Core-lab confirmed 0% stent fracture in both the RCT at two years and MIMICS-2 at one year. The unique BioMimics stent design procides haemodynamic and biomechanical benefits for primary and complementary stenting.”