Modeling of microbubbles pushed through clots via acoustic radiation force

Abstract

Previous studies have shown that thrombi, which may completely block the blood flow in a vessel, can be dissolved by ultrasound acting on echo-contrast agent microbubbles. The presumed mechanism is acoustic cavitation, the radial oscillations of the bubbles, which can exert locally large forces on the fibrin ropes that make up the clot matrix. However, the movement of the bubbles through the clot in the absence of flow suggests that acoustic radiation force also plays an important role. Because detailed mechanistic modeling of this process is not available, we present here a heuristic study in which microbubble transit times in gels of various porosities were measured and described by a simplified percolation theory. Results suggest considerations for optimizing the penetration of active microbubbles in sonothrombolysis.

The effect of ultrasound‐assisted thrombolysis studied in blood‐on‐a‐chip

“…The effects of US on thrombi dissolution include the following: (1) Thermal effects, where increased temperature near the thrombus boosts enzyme activity, thus accelerating thrombolysis 11,12 . (2) Acoustic radiation force, where the radiation force initiates microstreaming, potentially increasing thrombi permeability 13 . (3) Acoustic cavitation, generally divided into inertial and stable categories.…”

“…11,12 (2) Acoustic radiation force, where the radiation force initiates microstreaming, potentially increasing thrombi permeability. 13 (3) Acoustic cavitation, generally divided into inertial and stable categories. Inertial cavitation involves bubble movement dominated by the inertia of the surrounding liquid.…”