Perfusion‐dependent cerebral autoregulation impairment in hemispheric stroke
Loss of cerebral autoregulation (CA) plays a key role in secondary neurologic injury. However, the regional distribution of CA impairment after acute cerebral injury remains unclear because in clinical practice, CA is only assessed within a limited compartment. Here, we performed large‐scale regional mapping of cortical perfusion and CA in patients undergoing decompressive surgery for malignant hemispheric stroke.
In 24 patients, autoregulation over the affected hemisphere was calculated based on direct, 15‐20‐minute cortical perfusion measurement with intraoperative Laser Speckle Imaging and mean arterial blood pressure (MAP) recording. Cortical perfusion was normalized against non‐infarcted tissue and 6 perfusion categories from 0% to >100% were defined. The interaction between cortical perfusion and MAP was estimated using a linear random slope model and Pearson correlation.
Cortical perfusion and CA impairment were heterogeneously distributed across the entire hemisphere. The degree of CA impairment was significantly greater in areas with critical hypoperfusion (40‐60%: 0.42% per mmHg and 60‐80%: 0.46% per mmHg) than in non‐infarcted (>100%: 0.22% per mmHg) or infarcted (0‐20%: 0.29% per mmHg) areas (*p<0.001). Pearson correlation confirmed greater CA impairment at critically reduced perfusion (20‐40%: r=0.67; 40‐60%: r=0.68; 60‐80%: r=0.68) compared to perfusion >100% (r=0.36; *p<0.05). Tissue integrity had no impact on the degree of CA impairment.
In hemispheric stroke, CA is impaired across the entire hemisphere to a variable extent. Autoregulation impairment was greatest in hypoperfused and potentially viable tissue, suggesting that precise localization of such regions is essential for effective tailoring of perfusion pressure‐based treatment strategies.
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