Improved understanding of stent malapposition using virtual bench testing

Intravascular imaging techniques such as optical coherence tomography (OCT) and intravascular ultrasound (IVUS) are often used to assess strut apposition, but only provide limited insight into the three-dimensional appositioning behaviour of stents. Recently, a new approach has been introduced to study the phenomenon of incomplete stent apposition (ISA) based on finite element simulations. In this study, we employed this virtual strut apposition assessment technique in the setting of coronary bifurcation stenting and compared simulated strut-artery distances of two stent designs with actual measurements based on OCT imaging using a silicone model. Stenting of the main branch leads to malapposed struts in the proximal part and the average strut-artery distance in that region for the Integrity stent is 126 μm based on the simulation and 117±14 μm based on the OCT analysis. For the Multi-Link 8 stent, this average distance is 150 μm and 174±7 μm for the simulation and the in vitro OCT measurements respectively. In conclusion, the virtual assessment of strut appositioning results in similar strut-artery distances when compared with measurements based on OCT-visualised in vitro stent deployments and could be used to optimise devices and procedures.