In Vitro Analysis of the Efficacy of Endovascular Thrombectomy Techniques according to the Vascular Tortuosity Using 3D Printed Models

Mechanisms of thrombectomy failure in the tortuous anatomy model. A–C, Tortuous anatomy model. D–F, Nontortuous anatomy model. A, In the CA experiment, the thrombus is clogged at the tip of the aspiration catheter. The thrombus brushes against the tortuous vessel wall during retrieval and fragments when the aspiration catheter tip deflects perpendicular to the axis of the lumen at the angulated curve (white arrow, catheter tip alignment; black arrow, axis of the lumen and thrombus alignment). B, In the SR experiment, elongation and segmental collapse of the stent are noted (white arrows) when retrieving across the curved segment of the vessel, causing fragmentation of the thrombus. C, In the combined experiment, shearing of the thrombus occurred (white arrow) while crossing the curved segment when the SR was inadvertently pulled into the aspiration catheter during retrieval of the SR-CA unit due to aggravation of the length mismatch. D, In the CA experiment, the clogged thrombus and aspiration catheter show a more obtuse angle and are less deflected in the nontortuous anatomy model. E, The SR shows no elongation or segmental collapse at the curved segment of the vessel in the SR experiment, and there is no fragmentation or missing thrombus. F, In the combined experiment, the SR is not pulled into the aspiration catheter, and no shearing-off phenomenon is seen.