Impact of Endothelial Shear Stress on Absorption Process of Resorbable Magnesium Scaffold: A BIOSOLVE-II Substudy.

Background/purpose: Local hemodynamic forces such as endothelial shear stress (ESS) may have an influence on appropriate neointimal healing, vessel remodeling, and struts' absorption process following second-generation drug-eluting resorbable magnesium scaffold (RMS, Magmaris, Biotronik AG, Buelach, Switzerland) placement. The aim of this study was to investigate the impact of ESS assessed by optical coherence tomography (OCT)-based computational fluid dynamic (CFD) simulations on absorption process and coronary lumen dimension after Magmaris implantation.

Methods And Results: A total of 22 patients who were enrolled in the BIOSOLVE-II trial and underwent serial OCT assessment immediately after Magmaris implantation and at 6- and 12-month follow-up were included. We evaluated qualitative OCT findings frame by frame, and CFD simulations were performed to calculate the ESS at 3-dimensional (3D) reconstructed arteries. For quantitative calculation, the average ESS within each 1-mm section was classified into three groups: low (<1.0 Pa), intermediate (1.0-2.5 Pa), or high (>2.5 Pa). A significant difference of percentage remnants of scaffold was observed among the 3 groups at 12-month follow-up (P = 0.001) but not at 6-month follow-up. Low-ESS segment at baseline resulted in a greater lumen change of -1.857 ± 1.902 mm at 1 year compared to -1.277 ± 1.562 mm in the intermediate-ESS segment (P = 0.017) and - 0.709 ± 1.213 mm in the high-ESS segment (P = 0.001).

Conclusion: After Magmaris implantation, the presence of higher ESS might be associated with slower strut absorption process but less luminal loss.