Perfusion-Dependent Cerebral Autoregulation Impairment in Hemispheric Stroke

Area of Science:

• Neurology
• Neurosurgery
• Critical Care Medicine

Background:

• Loss of cerebral autoregulation (CA) contributes to secondary brain injury after acute cerebral injury.
• Current clinical assessments of CA are limited to specific brain compartments, leaving regional distribution unclear.

Purpose of the Study:

• To perform large-scale regional mapping of cortical perfusion and CA in patients undergoing decompressive surgery for malignant hemispheric stroke.
• To investigate the relationship between cerebral perfusion levels and the degree of CA impairment.

Main Methods:

• Intraoperative laser speckle imaging and mean arterial blood pressure (MAP) monitoring were used to measure cortical perfusion in 24 patients.
• Cortical perfusion was normalized to non-infarcted tissue, and CA was calculated using linear random slope models and Pearson correlation.
• Six perfusion categories were defined, ranging from 0% to over 100%.

Main Results:

• Cerebral autoregulation impairment was heterogeneously distributed across the hemisphere.
• Greater CA impairment was observed in critically hypoperfused areas (40-60% and 60-80% perfusion) compared to non-infarcted or infarcted regions.
• Pearson correlation confirmed significant CA impairment at critically reduced perfusion levels.

Conclusions:

• Cerebral autoregulation is impaired to varying degrees throughout the hemisphere following a stroke.
• Autoregulation impairment is most pronounced in hypoperfused, potentially viable brain tissue.
• Accurate localization of these compromised regions is essential for developing targeted, perfusion pressure-based treatment strategies.