In-Vitro Evaluations of Shape Memory Polymer Scaffolds with Tunable Architecture for the Endovascular Embolization of Unruptured Intracranial Aneurysms

Abstract

Clinically relevant performance metrics for shape memory polymer (SMP) scaffolds intended for the endovascular treatment of intracranial aneurysms were evaluated in various in-vitro experiments. Multiple SMP formulations were first evaluated for glass transition properties, with saturated scaffolds demonstrating Tg midpoints of 39 °C, 35 °C, and 32 °C, respectively. Then, scaffold?s porosity (85?95%) and infill pattern (rectilinear, honeycomb, gyroid) were systematically varied, and designs were compared by compressibility, shape recovery, and pulsatile compaction resistance. The compressibility of ideal and wide-necked aneurysm geometries, each in 6 mm and 8 mm diameter sizes, indicated an upper limit of ~9 mm in treatable aneurysm diameter for a 5 French microcatheter. Under physiologically relevant pulsatile loading, all scaffold designs resisted notable compaction, with maximum deformation values not exceeding 55 µm. The shape recovery forces were primarily governed by the porosity level, with low- and medium-porosity scaffolds showing complete and reliable shape recovery, and high-porosity scaffolds exhibiting reduced completeness of shape recovery. Shape recovery rates varied both within and across infill pattern and porosity groups. Together, these findings provide quantitative benchmarks for the performance of our SMP scaffold in different key stages of device deployment and establish design guidelines for further optimization of patient-specific endovascular devices.