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Cardiopulmonary perfusion and cerebral blood flow in bilateral carotid artery disease
P Johnsson1, L Algotsson, E Ryding
1Department of Thoracic Surgery, University Hospital, Lund, Sweden.
Insights
Patients with severe carotid artery disease undergoing coronary artery bypass grafting showed normal cerebral blood flow during cardiopulmonary bypass. Controlled perfusion prevents cerebral hypoperfusion in these high-risk patients.
Area of Science:
- Cardiovascular Surgery
- Neurology
- Cerebrovascular Medicine
Background:
- Patients with heart disease and severe carotid artery disease face risks of cerebral complications during cardiopulmonary bypass.
- Stroke risk is linked to carotid artery stenosis, with >75% reduction considered hemodynamically significant.
Purpose of the Study:
- To assess cerebral blood flow (CBF) in patients with severe bilateral carotid disease undergoing coronary artery bypass grafting (CABG).
- To compare CBF during cardiopulmonary bypass (CPB) between patients with and without carotid disease.
Main Methods:
- Xenon-133 washout technique used to measure CBF in 7 patients with severe carotid disease and 17 controls undergoing CABG.
- Measurements taken before, during, and after CPB under moderate hypothermia, alpha-stat acid-base regulation, and blood pressure >50 mm Hg.
Main Results:
- CBF levels (mL/100g/min) were nearly identical in both groups before (30±11 vs 30±11), during (31±8 vs 28±8), and after (47±20 vs 47±12) CPB.
- CBF was comparable between hemispheres in the carotid disease group and within normal ranges.
- Two patients had minor interhemispheric differences but no postoperative deficits.
Conclusions:
- Controlled cardiopulmonary perfusion appears to mitigate the risk of cerebral hypoperfusion in patients with critical carotid stenoses.
- The findings suggest that CABG can be safely performed in patients with severe carotid disease under specific perfusion management.
Abstract:
The fear of cerebral complications after cardiopulmonary bypass in patients with heart disease and severe carotid artery disease has led many authors to suggest combined approaches in these patients. The pathogenetic mechanism for stroke is based partly on the stenotic narrowing of the carotid artery. A diameter reduction of 75% is frequently considered hemodynamically significant and indicative of an increased risk for neurological morbidity. We studied the cerebral blood flow in 7 patients undergoing coronary artery bypass grafting who also had severe bilateral carotid disease. The results were compared with the results in 17 patients without carotid disease who had bypass grafting. The cerebral blood flow was measured by xenon 133 washout technique before, during, and after cardiopulmonary bypass with moderate hypothermia. Acid-base regulation was according to the alpha-stat theory, and blood pressure was kept greater than 50 mm Hg. The cerebral blood flow levels (mL.100g-1.min-1) before, during, and after cardiopulmonary bypass in the study group (30 +/- 11, 31 +/- 8, 47 +/- 20) (mean +/- standard deviation) were almost identical to those in the control group (30 +/- 11, 28 +/- 8, 47 +/- 12). The cerebral blood flow levels for the left and right hemispheres in the group with carotid disease were comparable and within normal ranges. In 2 patients, slight differences were noted between hemispheres, and this finding may indicate an increased risk for ischemia. These patients, however, did not show any signs of postoperative deficit. The flow limitations of critical carotid stenoses do not seem to imply a risk for cerebral hypoperfusion if cardiopulmonary perfusion is performed in a controlled manner.(ABSTRACT TRUNCATED AT 250 WORDS)