Solid and gaseous cerebral microembolization during off-pump, on-pump, and open cardiac surgery procedures

Area of Science:

• Neurology
• Cardiovascular Surgery
• Medical Imaging

Background:

• Neurocognitive dysfunction is a known complication of cardiac surgery involving cardiopulmonary bypass.
• Intraoperative cerebral microembolization is a primary suspected cause of this dysfunction.
• Advanced transcranial Doppler ultrasonography can detect and characterize microemboli.

Purpose of the Study:

• To compare the quantity and type of intraoperative cerebral microemboli between on-pump and off-pump cardiac surgery.
• To investigate the role of cardiopulmonary bypass and aortic manipulation in microemboli formation.

Main Methods:

• Bilateral continuous transcranial Doppler monitoring was used in 45 patients undergoing off-pump CABG, on-pump CABG, or open cardiac procedures.
• A multi-range, multifrequency system enabled measurement and discrimination of microemboli.
• Data were analyzed across three distinct surgical groups.

Main Results:

• Off-pump CABG had significantly fewer microemboli (median 40) than on-pump CABG (median 275) and open procedures (median 860) (P <.01).
• Solid microemboli constituted 12% in off-pump, 28% in on-pump CABG, and 22% in open procedures (P <.05).
• In on-pump groups, 24% of microemboli occurred during cardiopulmonary bypass and 56% during aortic manipulation.

Conclusions:

• Avoiding cardiopulmonary bypass substantially reduces cerebral microembolization during cardiac surgery.
• Most cardiac surgery-related microemboli are gaseous, but on-pump procedures show a higher proportion of solid microemboli.
• Differentiating between gas and solid microemboli is crucial for developing effective neuroprotective strategies.