Biomechanical analysis of thermal-plasty treatment for atherosclerosis with coupled thermal-electrical-structural model

Abstract:
Percutaneous transluminal angioplasty (PTA) and stenting are the common clinical treatments for atherosclerosis. However, several months later, re-narrowing of the artery, namely restenosis, frequently could occur. During this process, the endothelium is damaged due to the dilation force, which triggers the following inflammation response. Combining the radiofrequency ablation, convective cooling and balloon angioplasty, a novel thermal-plasty treatment has been proposed in our laboratory, which is expected to open the stenotic artery and ablate the plaque while protecting the endothelium. In the treatment, the radiofrequency heating after dilation of balloon could alter the stress of the artery, which is closely related with plaque rupture. To investigate the stress change in the artery wall during this treatment, a model coupled the radiofrequency transmission, heat transfer and stress field was established. The numerical results show that the elevated temperature of the artery can lower the stress by 18% and the percentage volume of plaque rupture is reduced in thermal-plasty treatment. Besides, a new treatment strategy, heating and smaller balloon dilatation degree, reduce stress by about 60%. This result implicates that the possibility of plaque rupture in this new treatment may be smaller than the traditional PTA. A new treatment strategy, that combining the heating and smaller degree of balloon dilation, was proposed.