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Abstract
Introduction Coil-assisted flow-diverter treatment of giant intracranial aneurysms suffers from high rupture rates (20%). Clinical outcomes can be improved by developing better predictable-rupture benchtop models. Commercially available models are relevant to neuro-interventionalists (surgical training) and device manufacturers (device testing and comparison). Patient-specific aneurysm morphology and neurovascular flows can be recreated using a 3D-printed aneurysm-rupture model connected to a physiologically relevant flow system.
Experimental approach Saccular-shaped, side-wall giant aneurysm (25mm in diameter, 1mm wall thickness) with a circular shaped distal defect (8mm diameter, <1mm thickness) in the aneurysm dome was 3D-printed on 4mm diameter parent vessel and optimized to rupture in <30min when connected to a neurovascular flow system (figure 1-Top). Flow was set to 150 - 200ml/min, pressure to 120/80mmHg (intra-aneurysmal pressure), and pulse to 60-beats/min (SuperPump AR, ViVitro Labs). Four treatment scenarios were tested in parallel: control group (untreated), flow-diverter only treated group (FD-group), coil-assisted flow diverter group (FD+Coil-group) and liquid-embolic assisted flow-diverter (FD+LE-group - NeuroCURE™, Aneuvas Technologies Inc.). Treatment was administered at t=5-min after establishing neurovascular flow conditions using digitally controlled, programmable hydraulic pulsatile pump. Real-time intra-aneurysmal pressure data was recorded using LabVIEW® software and data acquisition (DAQ) hardware. The flow system was run for at least 12 hours, with flow bypass activated for tests groups that ruptured prior to 12 hours. Rupture times were noted for all four groups (n=4) and the flow setup was repeated three times (n=3).
Results Under neurovascular flow conditions, all three control models predictably ruptured <30min per design (figure 1-Bottom). The FD-group and FD+Coil-group ruptured at >30min and <12 hours. Lastly, none of the FD+LE-groups ruptured during the 12-hr run-time. The intra-aneurysmal pressure data showed no reduction in pressure in the control groups and minimal pressure reduction in the FD-group and FD+Coil-group. There was significant reduction in intra-aneurysmal pressure in the FD+LE-group, verifying complete filling of the aneurysm sac significantly affects aneurysmal pressure versus flow diversion, with or without adjunctive coiling.
Conclusion This study demonstrates the utility of predictable aneurysm rupture models for quantifying and correlating pressure effects to rupture times for various endovascular device treatments. Future models can likely be 3D-printed with patient-specific morphologies and used by neuro-interventionalists and device manufacturers to assess device treatment options in lieu of animal (in vivo) models or current glass or silicone models.
Top: 3D-printed giant aneurysm with a distal circular defect (red-orange circle) and pressure tap (green arrow). Bottom: Intra-aneurysmal pressure data - control aneurysm rupture (pressure drop from 120/80 to ~80/50 mmHg) at ~14min
Disclosures H. Sodawalla: None. J. Wells: None. M. Alnajrani: None. S. Schwartz: None. H. Gardner: None. T. Becker: 4; C; Aneuvas Technologies, Inc.