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Abstract
Introduction This research evaluates neurosurgical force and energy effects from the placement of endovascular catheters into (push) and out of (pull) tortuous neurovascular silicone models (United Biologics - UB). Excised swine carotid vessels were positioned and sutured within pre-sized silicone vessels with pre-set tortuosity. Four test catheter sizes (SL-10 1.7F-Stryker, 2.6F Headway-Medtronic, and Imperative Care’s 6.3F Zoom 71 and 8F Zoom 88) were tested under simulated physiological conditions within the benchtop swine models within 48 hours of vessel excision.
Materials and Methods Push and pull forces were measured by the Bioengineering Devices Lab (BDL) at Northern Arizona University (NAU) using a hybrid DMA-rheometer (HR2, TA Instruments). A 3D-printed mounting plate with a funnel bypass system held the guide catheter/sheath under the vertical rheometer force plate. The funnel system redirected the positively pressurized flow exiting the catheter lures (hemostatic valves were avoided, to eliminate excess friction effects). The vessel models were connected to a flow system, filled with phosphate-buffered saline (PBS), maintained at 37°C, and monitored for real-time pressure and flow (Deltran pressure transducers - Utah Medical, connected to LabView Data Acquisition system (DAQ) -National Instruments). The force plate pushed/pulled catheters at 0.25 cm/s from the tip of the guide catheter/sheath 8.5 cm into the vessel model (figure 1-Top). Four test catheters (n=4) were placed in two swine vessel-silicone models (n=2, left and right carotids). Each test repeated four times (n=4). All friction data were subtracted from the baseline forces (i.e., test catheter interaction with the guide catheter/sheath only).
Results Catheter force plots were created (figure 1-Bottom) and average force and energy data (area under the force-distance curves) were compared. Tracking small and medium catheters within the swine vessel exhibited small friction forces. Large 8F aspiration catheters exhibited statistically higher friction forces, at least 4X greater than the smaller catheter systems.
Conclusion Analysis of friction forces and energies were consistent among tested swine vessels, within 5% error. Quantifying friction forces in fresh animal vessels can be directly correlated to the human condition, based on established data on human and animal vessel lubricity. Testing of the latest benchtop vessel models, made from innovative silicone and 3D-printed materials, can now be statistically compared to the animal vessel data and correlated to the human condition. Quantifying the ‘feel’ of catheter progression can provide a platform for improved endovascular surgical simulations, statistical comparison of new endovascular device trackability, and a reduction of animal model usage.
Top: Push/Pull setup - DMA-rheometer, catheter mount, vessel model, flow system, and pressure monitoring. Bottom: Average forces of four catheter sizes within the swine vessel
Disclosures J. Wells: 5; C; Northern Arizona University, Aneuvas Technologies, Inc. C. Fisher: 5; C; Northern Arizona University. M. Anlajrani: 5; C; Northern Arizona University. J. Vigil: 5; C; Northern Arizona University. O. Fisher: 5; C; Northern Arizona University. G. Becker: 5; C; Northern Arizona University. W. Merritt: 2; C; United Biologics. 4; C; Aneuvas Technologies, inc.. 5; C; Aneuvas Technologies, Inc. A. Ducruet: 2; C; Medtronic, Penumbra, Oculus, Stryker, Balt, Koswire. 4; C; Aneuvas Technologies, inc.. 5; C; Barrow Neurological Institute. T. Becker: 1; C; United Biologics. 2; C; United Biologics. 4; C; Aneuvas Technologies, Inc.. 5; C; Northern Arizona University.