In vitro and in vivo evaluation of a shape memory polymer foam‐over‐wire embolization device delivered in saccular aneurysm models

Abstract

Current endovascular therapies for intracranial saccular aneurysms result in high recurrence rates due to poor tissue healing, coil compaction, and aneurysm growth. We propose treatment of saccular aneurysms using shape memory polymer (SMP) foam to improve clinical outcomes. SMP foam-over-wire (FOW) embolization devices were delivered to in vitro and in vivo porcine saccular aneurysm models to evaluate device efficacy, aneurysm occlusion, and acute clotting. FOW devices demonstrated effective delivery and stable implantation in vitro. In vivo porcine aneurysms were successfully occluded using FOW devices with theoretical volume occlusion values greater than 72% and rapid, stable thrombus formation.

Shape memory polymers with visible and near-infrared imaging modalities: synthesis, characterization and in vitro analysis

“…1–10 SMPs can be processed into a variety of geometries, including highly porous, ultra-low density foams. 1,2 A range of SMPs have been proposed for use in medical applications, and polyurethane SMPs are of particular interest due to their excellent biocompatibility.…”

“…1,2 A range of SMPs have been proposed for use in medical applications, and polyurethane SMPs are of particular interest due to their excellent biocompatibility. 3–10 Polyurethane SMP foams have demonstrated rapid, stable blood clot formation, superior immune response compared with polypropylene and silk, and tunable shape recovery for void filling. 10,11 These foams have been proposed for use in several medical device applications, including aneurysm occlusion, peripheral occlusion, and vascular and coronary grafts.…”

Particulate Release From Nanoparticle-Loaded Shape Memory Polymer Foams

“…Additionally, their unique shape memory properties enable their catheter delivery through tortuous vasculature to the desired treatment site, where they expand to fill the site and promote clotting. Overall, these results combined with the positive prior in vivo study results indicate that the SMP foams present minimal risks from particulate release that may result in unintended downstream emboli formation and have high potential for use as effective and safe embolization devices [4,5,16,28].…”

“…However, all foams that are used in devices are reticulated and subjected to extensive cleaning processes [5] that serve to remove the particulates along with unreacted monomers and catalysts prior to implantation. Future work will focus on characterizing prolonged particulate release from foams under physiological flow conditions and under device delivery conditions.…”

“…However, due to an increase in the use of sophisticated imaging technology, prerupture aneurysm detection rates are rising [3]. Porous, low density shape memory polymer (SMP) foam is reported to be an effective aneurysm occlusion material with excellent biocompatibility as seen in a porcine model wherein rapid, stable thrombus formation and high volume occlusion was observed [4,5]. SMP foams are materials capable of maintaining a temporary shape and, upon application of a thermal, chemical, or optical stimulus, recovering their primary shape [6].…”