Cerebral Circulation During Retrograde Cerebral Perfusion: Evaluation Using Laser Speckle Flowgraphy

Area of Science:

• Cardiovascular Surgery
• Neurology
• Medical Imaging

Background:

• Cerebroprotective effects of retrograde cerebral perfusion (RCP) and selective antegrade cerebral perfusion (SCP) are debated.
• Laser speckle flowgraphy offers novel perioperative neuromonitoring by assessing optic nerve head blood flow.

Purpose of the Study:

• Evaluate human cerebral microcirculation using laser speckle flowgraphy during circulatory arrest, RCP, and SCP under moderate hypothermia.
• Investigate the reliability of RCP for cerebral protection in this context.

Main Methods:

• 23 patients undergoing thoracic aorta aneurysm surgery were enrolled.
• Laser speckle flowgraphy measured cerebral circulation (mean blur ratio) at multiple time points.
• Measurements included baseline, cardiopulmonary bypass, simple circulatory arrest, RCP, and SCP.

Main Results:

• Mean blur ratios during simple circulatory arrest and RCP were significantly decreased versus baseline.
• No significant difference in mean blur ratio was found between simple circulatory arrest and RCP.
• Mean blur ratio was significantly higher during SCP compared to both simple circulatory arrest and RCP.

Conclusions:

• Retrograde cerebral perfusion (RCP) did not show a significant difference in cerebral circulation compared to simple circulatory arrest under moderate hypothermia.
• Selective antegrade cerebral perfusion (SCP) resulted in significantly higher cerebral circulation than both simple circulatory arrest and RCP.
• Cerebral microcirculation may be inadequate during RCP compared to SCP under moderate hypothermia, questioning its efficacy as a sole protective strategy.