Experimental investigation of the stent-artery interaction

It is well acknowledged that stent implantation causes abnormal stretch and strains on the arterial wall, which contribute to the formation and progression of restenosis. However, the experimental characterization of the strain field on the stented vessel is scant. In this work, the balloon-expandable stent implantation inside an artery analogue was captured through two high-speed CCD cameras. The surface strain maps on the stented tube were quantified with a 3-D digital image correlation technique. The strain history at one specific reference point illustrated three stenting phases, including balloon inflation, pressurization and deflation. The surface strain distributions along one axial path were obtained at various time points to demonstrate the stent-vessel interactions. The radial wall thickness reduction history was used to evaluate the pressure-diameter relationship for the balloon. Results indicated that the expansion process of the balloon was significantly altered by the external loadings from both the stent and artery analogue. In addition, the repeatability of the stenting experiments was demonstrated through two tests with a change of 5% in the stent-induced maximum first principal strain. Moreover, a computational model of the stenting procedure was developed to recapture the stenting experiments. Comparison between experiments and simulation showed a difference of 7.17% in the first principal strain averaged over the high strain area. This indicated the validation of the computational framework, which can be used to investigate the strain or stress field throughout the computational domain, a feature that is not affected by experimental techniques.