Multi-objective optimization of coronary stent using Kriging surrogate model
The foreshortening or dogboning of a stent that occurs due to transient non-uniform balloon-stent expansion can induce a vascular injury, resulting in restenosis of the coronary artery. However, previous studies rarely considered the effects of transient non-uniform balloon expansion on analysis of the mechanical properties and behaviors of stents during stent deployment, nor did they determine design parameters to minimize the restenosis risk driven by foreshortening or dogboning. The aim of the current study was, therefore, to suggest potential design parameters capable of reducing the possibility of restenosis risk driven by foreshortening or dogboning through a comparative study of seven commercial stents using finite element (FE) analyses of a realistic transient non-uniform balloon-stent expansion process. The results indicate that using stents composed of opened unit cells connected by bend-shaped link structures, in particular the MAC Plus stent, and controlling the geometrical and morphological features of the unit cell strut or the link structure at the distal ends of stent may prevent restenosis risk caused by foreshortening or dogboning. This study provides a first look at the realistic transient non-uniform balloon-stent expansion by investigating the mechanical properties, behaviors, and design parameters capable of reducing the possibility of restenosis risk induced by the foreshortening or the dogboning.