Numerical Simulation and Experimental Study on Vascular Mechanical Properties of Coronary Degradable Stent Intervention / 医用生物力学

ABSTRACT

Objective To explore the effect of vascular stress changes on endothelial function recovery and vascular restenosis inhibition in dynamic degradation process of the degradable stent. Methods The material parameters of the hyper-elastic vascular constitutive relationship was fitted, and the stress distribution on the intima of the blood vessel before stent implantation and during dynamic degradation was calculated by numerical simulation. In vitro culture experiments were carried out, and the stretch ratios of the silicon chambers were 0%, 5%, 10% and 15%, respectively, to simulate the mechanical environment at different degradation stages, and to explore the effects of different stretch ratios on growth state of the endothelial cells （ECs）. Results After the stent was completely degraded, the circumferential intimal stress and strain of the vessel were restored to 0.137 MPa and 5.5%, which were close to the physiological parameters (0.122 MPa, 4.8%) before stent implantation. In vitro experiments showed that the survival rate of ECs was the highest under the condition of 0.1 MPa circumferential stress and 5% strain, and adhesion growth could be achieved. Conclusions With the occurrence of stent degradation process, the circumferential stress and strain of the intima were restored to a range close to physiological parameters, which promoted the growth of ECs. The recovery of intimal function could effectively inhibit the process of vascular restenosis. The results can provide the theoretical basis and experimental platform for studying coronary intervention for the treatment of vascular restenosis.