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Pattern and significance of cerebral microemboli during coronary artery bypass grafting
S Sylivris1, C Levi, G Matalanis
1Department of Cardiology, Austin and Repatriation Medical Centre, Heidelberg, Victoria, Australia.
Insights
Cerebral microemboli during coronary artery bypass grafting are linked to neuropsychological deficits. However, strokes detected by MRI show higher microemboli before surgery, not during bypass.
Area of Science:
- Neurology
- Cardiovascular Surgery
- Medical Imaging
Background:
- Strokes during coronary artery bypass grafting (CABG) are frequently caused by embolism.
- Intraoperative transcranial Doppler (TCD) monitoring can detect cerebral microemboli.
- Understanding microembolic patterns is crucial for stroke prevention in CABG patients.
Purpose of the Study:
- To identify the pattern of microembolic phenomena during different stages of CABG.
- To correlate high-intensity transient signals with early neuropsychological deficits.
- To determine if MRI-detected cerebral infarction correlates with microembolic load during bypass.
Main Methods:
- Forty-one patients undergoing CABG were monitored using TCD.
- All patients had pre- and post-operative MRI brain scans.
- A subgroup of 32 patients had their microembolic load compared with neuropsychological outcomes.
Main Results:
- Most microemboli were detected during cardiopulmonary bypass via TCD.
- A significant association was found between total microembolic load during bypass and early neuropsychological deficits (p = 0.008).
- Cerebral infarction on MRI correlated with higher microembolic signals during preincision phases, not during bypass.
Conclusions:
- Microembolic load during bypass surgery is linked to early neuropsychological deficits.
- Higher microembolic load during the preincision phase is associated with cerebral infarction.
- Distinct mechanisms may underlie microembolism-related outcomes in CABG patients.
Background:
Strokes that occur during coronary artery bypass grafting are often caused by embolism. Intraoperative transcranial Doppler monitoring can detect cerebral microemboli. The aims of this study were to identify the pattern of microembolic phenomena during various stages of coronary artery bypass grafting, to verify whether numbers of high-intensity transient signals correlated with early neuropsychologic deficits, and to identify, using magnetic resonance imaging scans, whether radiologic evidence of cerebral infarction correlated with microembolic numbers during the bypass period.
Methods:
Forty-one consecutive patients undergoing coronary bypass grafting with transcranial Doppler monitoring were enrolled in this study. All had preoperative and postoperative magnetic resonance imaging brain scans. A subgroup of 32 patients were studied by comparing microembolic load and early neuropsychological outcomes.
Results:
Transcranial Doppler monitoring confirmed that most microemboli occurred during cardiopulmonary bypass. A significant early neuropsychological deficit after coronary artery bypass grafting did correspond to the total microembolic load during bypass (p = 0.008). However, patients with cerebral infarction on magnetic resonance imaging had significantly more microembolic signal during the preincision phases and not during the bypass period.
Conclusions:
Microembolic load during bypass is associated with early neuropsychologic deficits. In contrast, patients who show evidence of strokes during coronary artery bypass grafting have a higher microembolic load during the preincision phase than those without cerebral infarction. Differing mechanisms may be responsible for these different outcomes.