Boundary Conditions and Long-Term Implantation Effects with Cardiovascular Nitinol Implants

Abstract

Nitinol-based cardiovascular implants are used frequently to treat a wide range of cardiovascular diseases. Accordingly, understanding the durability of these devices once deployed into the geometrically dynamic cardiovascular system is of critical importance. While the fundamental material properties of Nitinol are relatively well understood, the boundary conditions imposed on Nitinol-based devices by the cardiovascular system and the corresponding effects on durability are not as well understood. Moreover, longitudinal studies report mixed long-term outcomes which raises question about long-term durability of cardiovascular implants. Understanding of the physiologic boundary conditions with focus on the regions with high mobility can warrant not only the short-term benefit, but also the long-term success with minimized incidence of implant-driven complications. In this article, Nitinol-based implants for the aortic valve, cerebral arteries, thoracic aorta, renovisceral arteries, and peripheral arteries are considered, research studies characterizing related variations in cardiovascular geometry are detailed, and summaries of available clinical studies reporting on outcomes are provided.