Design and Development of Auxetic Coronary Stent for the Treatment of Coronary Heart Diseases

Abstract

Cardiovascular heart disease in the present era is one of the leading health problems and needs considerable healthcare resources to avoid these issues. This thesis is focused on new coronary stent development based on Auxetic geometry that causes the stent to exhibit negative Poisson’s ratio. Vascular system of the body shows anisotropic characteristics whereas commercially available coronary stents have isotropic properties. This results in a mismatch between stent isotropic-anisotropic properties and arterial wall which is not favorable for mechanical anchorage of available commercial available coronary stent with the arterial wall. It is believed that with inherent anisotropic mechanical properties the Auxetic coronary stent will have good mechanical anchorage with arterial wall. The Auxetic design was fabricated through laser cutting and surface treatment was performed via acid pickling and electropolishing process and followed by heat treatment. The mechanical performance of Auxetic coronary stent was analyzed through invitro mechanical analysis. Scanning electronic microscope (SEM) was used to determine fabrication processes effects on the Auxetic stent topography. The invitro mechanical analysis shows that Auxetic stent design will effectively maintain the luminal patency of the coronary artery. Also, it will prevent the stent migration problem by expanding in both radial and longitudinal directions, thus Auxetic coronary stent showed no foreshortening. The Auxetic stent bulges outwards when it is radially expanded through an inflated balloon by virtue of its synclastic behavior.