Design and Verification of Shape Memory Polymer Embolization Devices for Peripheral Indications

Abstract

Polyurethane shape memory polymers (SMPs) have found a variety of uses in the medical industry in the form of self-tightening sutures, suture anchors, ligament fixation devices, vascular stents, and thrombectomy devices. New formulations of polyurethane SMP scaffolds are gaining significant interest for use in vascular embolization procedures. These scaffolds have demonstrated rapid time to occlusion, improved healing, and favorable biocompatibility, and they eliminate the need to implant multiple devices to achieve stable occlusion, significantly reducing procedure times and the total cost of treatment. Described here are various methods used to fabricate SMP scaffolds, indications for SMP scaffold embolization, advantages of using these scaffolds in embolization procedures, results seen in vivo and in vitro to verify the safety and efficacy of the SMP scaffolds, and future directions for SMP scaffolds that will propel the technology to significant use beyond vessel occlusion.

The research described in this work resulted in the creation of novel embolic devices that have the potential to drastically reduce the cost of endovascular embolization procedures by reducing the number of devices required for treatment, radiation time, the need for repeat procedures, and the time to complete healing of the treated vessel. These devices also demonstrated resistance to undesired thromboembolism in vitro, while also exerting negligible radial force on the vessel endothelium to minimize the likelihood of vessel rupture or perforation. In vitro verification testing demonstrated that this device appears to be safe and effective for embolization within the peripheral vasculature. This work also represented the first verification of the echogenicity of shape memory polymer foam devices in vitro. In addition, this research solidified the designation of polyurethane shape memory polymer foam as a platform technology that can be combined with other material systems to create shape memory occlusive devices with enhanced fluid uptake and bactericidal properties.