Blood viscoelasticity response during carotid endarterectomy

Area of Science:

• Neurology
• Biomedical Engineering
• Cardiovascular Science

Background:

• Ischemic brain injury leads to microcirculatory disturbances and altered blood rheology.
• These changes result from complex interactions between blood cells and damaged endothelium, affecting blood viscosity and density.
• Understanding these rheological shifts is crucial for managing cerebral blood flow during interventions.

Purpose of the Study:

• To investigate the changes in blood rheology during carotid endarterectomy.
• To assess the impact of carotid clamping and shunting on blood viscosity and plasma density.
• To establish the correlation between blood rheology and cerebral blood flow.

Main Methods:

• Utilized an oscillating capillary rheometer and densimeter to measure complex viscosity and density of whole blood and plasma.
• Collected blood samples from the internal jugular vein of 17 patients undergoing carotid endarterectomy.
• Monitored rheological parameters during different surgical stages, including carotid clamping and shunt placement.

Main Results:

• Carotid clamping significantly increased whole blood viscoelasticity and plasma density, despite adequate collateral circulation.
• Installation of an intraluminal shunt led to a significant improvement in blood rheology, restoring initial values and enhancing shear velocity.
• Increased whole blood viscosity was directly correlated with decreased cerebral blood flow, with immediate and reversible effects.

Conclusions:

• Elevated blood viscosity is a significant indicator of reduced cerebral blood flow during carotid endarterectomy.
• Fluid shifts into the interstitium increase hematocrit density, contributing to rheological disturbances.
• Prompt restoration of blood flow is essential for reversing adverse rheological changes and improving cerebral perfusion.