A year ago the principal study investigator in Veryan’s Mimics study was guardedly optimistic and pointed to the need for longer term data. Now, at the same event a year on, two-year data have confirmed that BioMimics 3D™ provides a significant improvement in long-term primary patency compared to a straight nitinol control stent in patients undergoing femoropopliteal artery intervention.
BioMimics 3D is a nitinol stent with unique three-dimensional helical geometry, developed by Veryan based on pioneering research by Prof Colin Caro at Imperial College London into the link between blood flow mechanics and vascular disease. The stent’s unique helical centerline geometry is designed to mimic natural vascular curvature that promotes secondary (swirling) flow and elevated hemodynamic shear stress, which has a protective effect on the endothelium. The helical geometry of the BioMimics 3D femoropopliteal stent is also designed to enable coil-spring shortening of the stented segment during knee flexion and mitigate the risk of stented segment compression causing localized strains in a straight stent that may lead to stent fracture and chronic vascular injury. It all sounds incredibly plausible, but needs clinical support to back up its promise.
And that support comes in the form data out to 24 months, presented at the Late-Breaking Clinical Trials session at the VIVA14 symposium. Results indicate a statistically significant improvement in the Kaplan Meier estimate of survival from clinical-driven TLR through 24 months, when the helical stent is compared with the control “straight” stent (P<0.05).
The Mimics study is a prospective, randomized, multicenter controlled trial conducted at eight German investigational centers and supported by an independent core lab. A total of 76 patients were enrolled and randomized 2:1 (50 BioMimics 3D v 26 Control) in subjects undergoing femoropopliteal artery intervention. Mimics’ investigators compared the safety, efficacy and vascular hemodynamics of the BioMimics 3D stent to straight nitinol stents (24/26 control subjects were treated with LifeStent (CR Bard)).
Just like last year, data from the Mimics study were presented Principal Investigator Professor Thomas Zeller, Universitäts-Herzzentrum, Freiburg-Bad Krozingen, Germany. Highlights were:
- The Kaplan Meier (KM) survival estimate of freedom from loss of primary patency at two years was 72% for BioMimics 3D subjects vs. 55.0% for the control arm. The difference in survival estimate between the two groups by log rank test was significant (P<0.05).
- No increase in the KM estimate of clinically driven target lesion revascularization (CDTLR) rate in the BioMimics arm between 12 and 24 months (9% at both time-points) compared to a 3-fold increase (8% at 12 months and 24% at 24 months) in the straight stent control arm.
- An improvement of one or more Rutherford categories was observed in 87% of BioMimics 3D patients at 24-months compared to baseline.
- A core lab review of straight and flexed knee X-rays did not detect any stent fractures in any BioMimics 3D Stent.
- Bi-planar X-ray imaging data indicate the ability of the femoropopliteal artery to adopt the three-dimensional curvature of the BioMimics 3D stent and computational fluid dynamic modelling provided evidence of secondary (swirling) flow within the stented segment and predicted zones of elevated wall shear stress.
- Mimics Study data indicate a correlation between primary patency and stent curvature. BioMimics 3D stented segments showed significantly greater curvature (P= 0.02) compared with the control, providing swirling blood flow and elevated wall shear, which may explain the longer term patency protective effect seen with BioMimics 3D.
- Across all patients, stent curvature was greater for BioMimics 3D stents compared to the straight control stents and no loss of patency was observed in patients with mean straight leg stent curvature above 0.02 mm-1.
“These data suggest the existence of a patency protective effect provided by the biomimetic characteristics of the BioMimics 3D nitinol stent resulting in hemodynamic and biomechanical performance advantages over straight nitinol stents”, commented Professor Zeller.
“We are very grateful to Professor Zeller and the Mimics’ Investigators for enabling Veryan to complete this benchmark evaluation of the unique BioMimics 3D helical stent technology. We believe this advanced stent design offers outstanding benefits in femoropopliteal use and has potential for innovation in many other areas of endovascular intervention. Presentation of the full two-year Mimics’ results represents a major step forward in this endeavour”, added Veryan Chief Executive Chas Taylor.
Source: Veryan Medical, Ltd.