Degradable, Multifunctional Cardiovascular Implants: Challenges and Hurdles

Polymer-coated and polymer-based cardiovascular implants are essential constituents of modern medicine and will proceed to gain importance with the demographic changes toward a society of increasing age-related morbidity. Based on the experiences with implants such as coronary or peripheral stents, which are presently widely used in clinical medicine, several properties of the next generation of cardiovascular implants have been envisioned that could be fulfilled by multifunctional polymers. The challenge is to combine tailored mechanical properties and rapid endothelialization with controlled drug release in order to modulate environmental cells and tissue. Additionally, degradability and sensitivity to external stimuli are useful in several applications. A critical function in terms of clinical complications is the hemocompatibility. The design of devices with improved hemocompatibility requires advanced in vitro test setups as discussed in depth in this article. Finally, degradable, multifunctional shape-memory polymers are introduced as a promising family of functional polymers that fulfill several requirements of modern implants and are of high relevance for cardiovascular application (e.g., stent technology). Such multifunctional polymers are a technology platform for future cardiovascular implants enabling induced autoregeneration in regenerative therapies.