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Similar neurobehavioral outcome after valve or coronary artery operations despite differing carotid embolic counts
M J Neville1, J Butterworth, R L James
1Departments of Anesthesiology, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
Insights
Patients undergoing cardiac valve operations had more microemboli than those having coronary artery bypass grafting, but neurobehavioral outcomes were similar. Increased emboli correlated with poorer performance on one cognitive test.
Area of Science:
- Cardiovascular Surgery
- Neurology
- Medical Technology
Background:
- The relationship between cardiac surgery, microemboli, and neurological function is not fully understood.
- Cardiac valve operations and coronary artery bypass grafting are common procedures with potential embolic risks.
Purpose of the Study:
- To compare the number of microemboli during cardiac valve operations versus coronary artery bypass grafting.
- To investigate the association between microemboli and neurobehavioral outcomes in these patient groups.
Main Methods:
- Compared 193 patients undergoing coronary artery bypass grafting with 73 undergoing cardiac valve operations.
- Assessed neurobehavioral tests, neurologic, and neuro-ophthalmologic status preoperatively and postoperatively at multiple time points.
- Used Doppler ultrasonography to detect left common carotid artery emboli during surgery.
Main Results:
- Patients undergoing cardiac valve operations had significantly more emboli (median 479) compared to coronary artery bypass grafting (median 105).
- Despite higher emboli counts, neurobehavioral outcomes, stroke rates, and mortality did not differ significantly between groups.
- Increased carotid emboli numbers were associated with worse performance on the letter cancellation test.
Conclusions:
- Cardiac valve operations generate more microemboli, likely due to intracardiac air entrainment.
- Higher microemboli burden during valve surgery did not translate to worse neurological or neurobehavioral outcomes compared to coronary artery bypass grafting.
Objectives:
The interrelationships among coronary and valvular operations, microemboli, and neurobehavioral outcome are unclear. We hypothesized that adult patients undergoing cardiac valve operations would have more total emboli delivered to the brain than patients undergoing coronary artery bypass grafting and that this would associate with worse neurobehavioral outcomes.
Methods:
One hundred ninety-three patients undergoing coronary artery bypass grafting and 73 patients undergoing cardiac valve operations were compared. Patients received neurologic, neuro-ophthalmologic, and 11 standardized neurobehavioral tests preoperatively and 5 to 7 days, 1 month, and 6 months postoperatively. Left common carotid Doppler ultrasonographic embolus detection was performed intraoperatively. Repeated measures and logistic regression analyses of outcome were performed.
Results:
Patients undergoing either coronary or valve operations were well matched by age (61 +/- 10 and 59 +/- 12 years, respectively), but a significantly greater fraction of patients undergoing valve operations were female, diabetic, or had undergone previous cardiac operations. Neurobehavioral scores of patients undergoing either coronary artery bypass grafting or cardiac valve operations did not differ significantly at any time. Total embolus counts differed significantly: the median was 105 during coronary artery bypass grafting and 479 during cardiac valve operations (geometric means of 104 and 412, respectively; P =.0001). Significantly more emboli were detected in the patients undergoing cardiac valve operations after removal of the left ventricular vent and after separation from cardiopulmonary bypass, but comparable numbers of emboli were seen in the 2 groups before cardiopulmonary bypass. In both groups decreased neurobehavioral performance was apparent at 5 to 7 days, with improvement at 1 and 6 months. Increasing numbers of carotid emboli significantly associated with worse performance on the letter cancellation test. There were no significant differences between patients undergoing valve and coronary operations in neurobehavioral outcomes, strokes, transient ischemic attacks, or deaths.
Conclusions:
The significantly greater number of emboli in the group of patients undergoing cardiac valve operations is likely the result of the entrainment of intracardiac air. The greater numbers of emboli during cardiac valve operations do not appear associated with a commensurately greater risk of adverse neurologic or neurobehavioral outcome.