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Stroke associated with coronary artery bypass surgery
J H Hise1, M L Nipper, J C Schnitker
1Department of Radiology, Scott and White Clinic, Texas A & M University College of Medicine, Temple 76508.
Insights
Cerebral infarction after coronary artery bypass grafting is often caused by embolization, not hypoperfusion. This study reviews 30 neurologic events in patients undergoing bypass surgery.
Area of Science:
- Neurology
- Cardiovascular Surgery
Background:
- Neurologic events can occur after coronary artery bypass grafting (CABG).
- Acute ischemic injury is a concern during and after CABG procedures.
Purpose of the Study:
- To investigate the mechanisms of neurologic injury in patients undergoing CABG.
- To differentiate between cerebral embolization and hypoperfusion as causes of stroke post-CABG.
Main Methods:
- Retrospective review of medical records and neuroimaging for 30 patients with neurologic events post-CABG.
- Analysis of CT scans and carotid arteriograms to identify patterns of cerebral injury and vascular abnormalities.
Main Results:
- Thirty neurologic events were documented among 2029 CABG operations.
- CT scans revealed acute infarction in 15 patients, watershed lesions in two, and emboli/occlusion in others.
- Arteriography showed carotid artery occlusions and high-grade stenoses.
Conclusions:
- Cerebral embolization is the primary mechanism of ischemic injury in patients experiencing stroke after CABG.
- Findings challenge the notion that cerebral hypoperfusion is the main cause of infarction in this patient population.
Abstract:
Medical records and neuroimaging studies of 30 patients with major neurologic events after coronary artery surgery were reviewed. Two thousand and twenty-nine coronary artery bypass graft operations were performed in our institution between October 15, 1985, and December 27, 1989. Of these, there were 30 documented neurologic events suggesting acute ischemic injury during the intraoperative or the postoperative period. Clinical manifestations included hemiparesis, monoparesis, aphasia, bilateral cortical dysfunction, cortical and brainstem dysfunction, and left homonymous hemianopsia. There were five deaths directly attributable to neurologic injury. Twenty-two patients had a CT scan of the head, of which 15 showed evidence of acute infarction, two suggested watershed lesions from cerebral hypoperfusion, and the remainder showed findings consistent with multiple cerebral emboli or primary intracranial occlusion. Five carotid arteriograms and one digital subtraction arteriogram of the carotids were obtained. Angiographic findings revealed two common carotid artery occlusions, one callosal marginal artery occlusion, and two cases of bilateral high-grade internal carotid stenoses. Our findings support the contention that in patients who suffer cerebral infarction associated with coronary artery bypass grafting, the main mechanism of injury is cerebral embolization rather than cerebral hypoperfusion.