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Abstract
Introduction/Purpose Aspiration thrombectomy is the standard of care for large vessel occlusions. Although clot composition and hardness are known to affect fragmentation risk during aspiration, the role that clot composition plays in digestion rates is not as well understood. The purpose of this study is to assess synthetic clot aspiration effectiveness for hard and soft clots.
Materials and Methods Benchtop testing was performed to analyze the digestion rate of both hard (90% PAAM - ALG) and soft (83% PAAM - ALG) synthetic clot types. Synthetic clot aspiration digestion rates were assessed with the Bioengineering Devices Laboratory (BDL) benchtop flow model at Northern Arizona University (NAU). The model consists of a programmable, hydraulic pulsatile pump system (SuperPump AR, ViVitro Labs) that simulates physiological neurovascular flows and pressures. The benchtop system accommodates swappable 3D-printed circle of Willis (CW) flow models made from UV cured and acrylic-based co-polymers, which can replicate the mechanical properties of human vessels. The model also incorporates a novel and stable blood analog to mimic the viscosity and shear-thinning of blood, allowing real-time pressure and flow measurements at each CW branch. The two published synthetic blood clot analogs (soft and hard clots) were used to simulate clot aspiration.
In the benchtop model, the aspiration catheters, Zoom 88 (Z88 – Imperative Care) and Sofia (MicroVention) were advanced to the MCA, connected to a Zoom aspiration pump (Imperative Care) and used to remove soft and hard clot analogs. Various properties were evaluated during clot ingestion – tip geometry, catheter-to-vessel ratio (CVR), real-time pressure measurements corresponding to aspiration force, clot integration imaging, clot digestion rate into the vacuum pump, and first-pass efficiency (FPE) determined by real-time branch flow measurements.
Results Preliminary data from clot digestion rate suggest that the aspiration of hard synthetic clots correspond to greater clot integration and faster digestion rates while requiring less aspiration force. Larger-bore catheters with greater CVR can also enhance clot integration and digestion rates. Aspiration of soft synthetic clots corresponds to reduced clot integration and variable digestion rates with inconsistent FPE results.
Conclusion The relationship between clot composition and digestion provides more context regarding clinical variations in aspiration efficacy, which may help to inform treatment decisions. Further testing will include
Top: BDL-NAU benchtop flow model with real-time pressure and flow monitoring in each CW branch. A) hard clot lodged in Cavernous ICA B) catheter engaged with clot C) clot digested into catheter
Disclosures H. Berns: None. O. Asgari: None. J. Wells: None. J. Vigil: None. W. Merritt: 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: 4; C; Aneuvas Technologies, Inc.. 5; C; Aneuvas Technologies, Inc., Northern Arizona University.