Related Experiment Video
Updated: Jul 17, 2026
Surgical Porcine Model of Chronic Myocardial Ischemia Treated by Exosome-laden Collagen Patch and Off-pump Coronary Artery Bypass Graft
Published on: September 15, 2023
Neurocognitive function and cerebral emboli: randomized study of on-pump versus off-pump coronary artery bypass
Reza Motallebzadeh1, J Martin Bland, Hugh S Markus
1Department of Cardiac Surgery, St. George's Hospital Medical School, London, United Kingdom.
Insights
Off-pump coronary artery bypass graft (CABG) surgery shows better short-term neurocognitive function compared to on-pump CABG, likely due to fewer cerebral emboli. However, this cognitive advantage does not last long-term.
Area of Science:
- Cardiovascular Surgery
- Neuroscience
- Medical Technology
Background:
- Coronary artery bypass graft (CABG) surgery can lead to neurocognitive impairment.
- Cerebral emboli, particularly during cardiopulmonary bypass, are suspected causes.
- This study compares neurocognitive outcomes and cerebral emboli between on-pump and off-pump CABG.
Purpose of the Study:
- To compare neurocognitive function in patients undergoing on-pump versus off-pump CABG.
- To assess the incidence of cerebral emboli in both surgical groups.
- To determine if differences in neurocognitive function persist over time.
Main Methods:
- 212 patients were randomized to on-pump (n=104) or off-pump (n=108) CABG.
- Cerebral embolic signals were monitored using transcranial Doppler ultrasonography.
- Neurocognitive tests were performed preoperatively, at hospital discharge, 6 weeks, and 6 months post-surgery.
Main Results:
- Off-pump CABG patients had significantly better neurocognitive scores at hospital discharge (0.25 SD greater, p=0.01).
- On-pump CABG had substantially more embolic signals (median 1,605 vs. 9, p<0.001).
- No significant neurocognitive differences were observed at 6 weeks or 6 months post-surgery.
Conclusions:
- On-pump CABG is associated with a higher prevalence of cerebral emboli.
- Off-pump CABG demonstrates superior short-term neurocognitive function post-discharge.
- The neurocognitive benefits of off-pump CABG are not sustained at 6 weeks and 6 months.
Background:
Neurocognitive impairment can be a debilitating complication after coronary artery bypass graft surgery (CABG). Cardiopulmonary bypass, in particular, cerebral emboli, has been implicated. We compared neurocognitive function and cerebral emboli in patients undergoing on-pump and off-pump CABG.
Methods:
212 patients admitted for CABG were randomly assigned to on-pump (n = 104) or off-pump (n = 108) surgery. Embolic signals were detected with bilateral transcranial Doppler ultrasonography of the middle cerebral artery. Neurocognitive tests were administered preoperatively, on discharge from hospital, at 6 weeks, and at 6 months after surgery. Composite neurocognitive scores were derived using principal component analysis and were compared between the two groups, using analysis of covariance to adjust for baseline values.
Results:
At discharge from hospital, the adjusted composite neurocognitive score was 0.25 standard deviations greater in the off-pump group compared with the on-pump group (95% confidence interval: 0.05 to 0.45; p = 0.01). There was no significant difference at 6 weeks (0.09 standard deviations, 95% confidence interval: -0.11 to +0.30; p = 0.4) and 6 months (-0.002 standard deviations, 95% confidence interval: -0.23 to +0.23; p = 1.0). Median number of embolic signals was 1,605 (751 to 2,473) during on-pump and 9 (4 to 27) in off-pump CABG (p < 0.001). Age, length of education, and on-pump status were independent predictors of the predischarge neurocognitive score (p = 0.02, 0.03, and 0.006, respectively).
Conclusions:
Cerebral emboli are more prevalent during on-pump CABG. At discharge from hospital, neurocognitive function is better after off-pump surgery, possibly as a result of the lower embolic load. However, the difference in neurocognitive function does not persist at 6 weeks and 6 months.
