Collateral flow and pulsatility during large vessel occlusions: insights from a quantitative in vitro study

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Neuroscience

Background:

• Acute ischemic stroke from large vessel occlusions requires neurovascular interventions.
• Circle of Willis (CoW) hemodynamics are critical for treatment success.
• Limited in vivo data and accurate flow models exist for pathological collateral flow during large vessel occlusions.

Purpose of the Study:

• To develop and validate a novel in vitro flow model simulating CoW hemodynamics during large vessel occlusions.
• To investigate the impact of different arterial occlusions on collateral flow within the CoW.
• To provide transient hemodynamic data for pathological collateral flow.

Main Methods:

• Utilized a circulatory loop to generate reproducible cerebrovascular flows and pressures.
• Employed non-invasive flow visualization and high-resolution measurements in an anatomical CoW phantom.
• Simulated occlusions in the middle cerebral artery, terminal carotid artery, and basilar artery.

Main Results:

• Mean arterial and pulse pressures remained stable across occlusion scenarios.
• Total cerebral flow decreased by up to 19% during occlusions.
• Reversed flow was observed in the left posterior communicating artery in all occlusion cases, with varying magnitudes and pulsatility.

Conclusions:

• The developed flow setup accurately replicates physiological and pathological CoW hemodynamics.
• This model provides valuable data for understanding collateral circulation during large vessel occlusions.
• The setup enables preclinical investigation of neurovascular interventions under controlled conditions.