Abstracts & Commentary
Sources: Bond R, et al. Systematic review of the risks of carotid endarterectomy in relation to the clinical indication for and timing of surgery. Stroke. 2003;34:2290-2301; Crisby M. Editorial comment. Risk stratification by clinical symptoms and timing of carotid endarterectomy: How could it optimize our decision making and benefit patients with carotid stenosis? Stroke. 2003;34:2302-2303.
Bond and associates reviewed data from 383 reports on carotid endarterectomy (CEA). The data from 60 of the studies, involving more than 14,000 cases of CEA, demonstrated an operative risk and death for asymptomatic stenosis of 2.8 vs 5.1% for symptomatic stenoses reported in 95 studies. The absolute risk for stroke and death from CEA was less than 3% for patients with only ocular ischemic events but as high as 19.2% for patients with ongoing cerebral symptoms. CEA for patients with either cerebral TIA or stable cerebral stroke was associated with a higher risk than surgery for ocular events only. Unstable patients, defined as those with stroke in evolution and crescendo TIA, presented with the highest operative risk, although only 13 studies, each with a low number of cases, reported the outcome of "urgent" CEA. The results were consistent in all studies: Urgent CEA for evolving symptoms had a much higher risk (19.2%) than CEA for stable symptoms (3.9%). There was no difference between early (less than 3-6 weeks) and late (greater than 3-6 weeks) CEA for stroke and stable TIA patients. Bond et al conclude that their analyses showed that the risk of stroke and death resulting from CEA is highly dependent on the clinical indication, and they suggest that reports of surgical risk should be stratified accordingly. Specifically, they found that patients with only ocular ischemic events were closer in risk to patients with asymptomatic stenoses. As to the timing of surgery, the operative risk of CEA in the acute phase of ongoing cerebral ischemia was too high to justify urgent CEA in routine clinical practice. CEA in the subacute phase in patients with a stable neurologic syndrome was not associated with a higher operative risk than later surgery. As pointed out by Crisby in her editorial comment, progress in therapeutic decision making for CEA is essential for minimizing the risk of stroke and death resulting from CEA.
Bond et al have shown by their metaanalysis that the classification of ischemic events into different categories such as ocular TIA, cerebral TIA, and cerebral infarction leads to differences in surgical operative risk and benefit. The ad hoc committees of the American Heart Association Stroke Council have established guidelines on the acceptable operative risk of CEA. The guidelines recommend that the combined risk of stroke and death resulting from CEA should not exceed 3% in asymptomatic patients, 5% in symptomatic patients with TIA, and 7% for those with stroke. Therefore, as the metaanalyses of Bond et al showed, it is important to classify the nature of the ischemic event preoperatively, especially to separate purely ocular from cerebral TIAs and stable patients from unstable patients in order to assure that the patient considered for CEA is an acceptable operative risk, that is, one that is within the American Heart Association Stroke Council’s guidelines. — John J. Caronna, Vice-Chairman, Department of Neurology, Cornell University Medical Center; Professor of Clinical Neurology, New York Hospital; Associate Editor, Neurology Alert.