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Abstract
Introduction/Purpose In-vitro models help test new medical devices for use in numerous cardiovascular and neurovascular treatments. These models are also commonly used for the training of surgeons on innovate devices and new surgical procedures. These current vessel-training models cast from human vasculature with anatomical accuracy; however the materials often used for casting (i.e. silicone and glass) do not accurately simulate mechanical properties of tissue such as: vascular compliance (modulus), tensile and compressive strength, wall friction (lubricity), and hardness seen in native human vasculature. Thus, a more tunable and comprehensive in-vitro model material is needed to better understand how endovascular devices (i.e. microcatheters/wires, thrombectomy devices, coils, stents, flow diverters, and liquid embolics) interact with the vessel wall during delivery. An innovative 3D printed acrylic co-polymer (VeroClear® Agilus30® – VC-A30) can be tuned to match the mechanical properties of human vessels.
Materials and Methods Differing hardnesses of VC-A30 are layered and mechanically characterized with a hybrid rheometer (DHR 2, TA Instruments). The results are compared to replicated test results of donated ‘fresh’ human cadaveric tissue samples (Common Carotid Artery). Via the rheometer, data is collected for luminal wall friction, radial compliance, shear modulus, and elastic modulus (figure 1). Properties of cadaveric vessels and model materials are statistically compared to the VC-A30. The biomaterial layering is altered by varying the thickness of the VC-A30 layer thicknesses (biomaterial tuning) to mimic the mechanical properties of the cadaveric vasculature within statistical equivalence. Once successfully optimized, the biomaterials are manufactured into flow models and will additionally be validated by partnered neurointerventionalists to ensure that the model has realistic catheter trackability and is anatomically accurate.
Results The VC-A30 materials in the previous studies simulated the compliance and mechanical properties of human vasculature more closely than existing in-vitro silicone materials. VC-A30 is 3D printed to achieve accurate anatomical features; moreover, this 3D printed material is layered to simulate the lubricious inner lumen of a vessel, with varying hardness profiles to mimic vessel compliance and strength. This assembled structure simulates the layers of human vasculature and its variable properties.
Conclusion The utilization of novel biomimetic materials within this in-vitro vascular flow model will allow for more relevant benchtop testing of endovascular devices. These models have the potential to generate more accurate data on device performance and may reduce the need for costly in-vivo studies.
Disclosures N. Norris: None. I. Smith: None. C. Settanni: None. W. Merritt: None. T. Becker: 1; C; 2018 BAF Grant. 6; C; Significant Financial Interest in ATI.