Endothelialization and Inflammatory Reactions After Intracardiac Device Implantation

Due to the advances in catheter-based interventional techniques, a wide range of heart diseases can now be treated with a purely interventional approach. Little is yet known regarding biological effects at the intracardiac implantation site or the effects on endothelialization and vascular inflammation in an in vivo environment. Detailed knowledge of ongoing vascular response, the process of endothelialization, and possible systemic inflammatory reactions after implantation is crucial for the clinical routine, since implants usually remain in the body for a lifetime.

For this narrative review, we conducted an extensive profound PubMed analysis of the current literature on the endothelialization processes of intracardially implanted devices, such as persistent foramen ovale (PFO) occluders, atrial septal defect (ASD) occluders, left atrial appendage (LAA) occluders, transcatheter aortic valve implantations (TAVIs), and leadless pacemakers. Additionally, the known biological activities of common metallic and synthetic components of intracardiac devices in an "in vivo" setting have been evaluated.

Nitinol, an alloy of nickel and titanium, is by far the most commonly used material found in intracardiac devices. Although allergies to both components are known, implantation can be performed safely in the vast majority of patients. Depending on the device used, endothelialization can be expected within a time frame of 3-6 months. For those patients with a known allergy, gold coating may be considered as a viable alternative.

Based on our analysis, we conclude that the vast majority of devices are made of a material that is both safe to implant and nontoxic in long-term treatment according to the current knowledge. The literature on the respective duration of endothelialization of individual devices however is highly divergent.