Poly-vinyl alcohol hydrogel vascular models for in vitro aneurysm simulations: The key to low friction surfaces

Purpose: To develop a vessel model with poly-vinyl alcohol hydrogel (PVA-H) with low surface friction for in vitro simulations of vascular pathologies. Materials and methods: Simulations of variable vascular pathologies were based on human vessel casts reproduced in wax. Constructions of vascular models were then obtained by lost wax techniques. As materials, liquid silicon or PVA in organic solvents were used. After solidification, the wax was drained by heating. Comparison of PVA-H with silicone models included evaluation of surface characteristics (friction coefficient), of visibility (transparence and compatibility with medical imaging techniques), and of stiffness (pulsatility of vascular lumen). Both model types were integrated in a circulation circuit allowing for flow simulations and testing with endovascular medical devices. Results and conclusion: Both model types were transparent and compatible with current medical imaging methods. PVA-H models exhibited much lower friction characteristics. PVA-H stiffness was closer to soft tissue when compared to silicone, allowing for pulsations during flow simulations.