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Carotid artery balloon angioplasty and stenting (CABAS): a neuroradiologic perspective.

Stroke is the third leading cause of death in the United States, with at least half a million strokes newly diagnosed per year. Most are noncardiogenic, and the majority of those are related to carotid artery atherosclerosis. The cost of treating stroke totals more than $30 billion a year, which does not include the emotional and social costs involved (1). There are effective treatments for carotid artery disease. Randomized prospective surgical trials (North American Symptomatic Carotid Endarterectomy Trial [NASCET] and European Carotid Surgery Trial [ECST]) have shown a significant reduction in the risk of stroke in symptomatic patients with severe carotid stenosis (.70%) who undergo carotid endarterectomy versus optimal medical therapy. In the NASCET study, symptomatic patients with greater than 70% stenosis had a 2-year cumulative risk of stroke of 26% with optimal medical therapy, versus 9% risk with carotid endarterectomy (P , .001). For major stroke and death, a risk reduction of 10.6% was identified with surgery. A recent reassessment by the American Heart Association (AHA) Stroke Council indicates that carotid endarterectomy is three times as effective as medical therapy alone in reducing the frequency of stroke (2). The benefits are dependent on maintaining a low complication rate. The perioperative stroke/ death rate for symptomatic patients in the NASCET study was 5.8%, and the rate of major stroke and death was 2.1%. For the ECST study, the rate of stroke and death was 7.5%. These rates include any event after randomization, even when preoperative. While the demonstrated utility of surgery for improving outcome in patients with severe carotid stenosis is an important advance, the complication rates, while acceptable, leave room for improvement. In fact, some authors suggest that since surgical expertise varies in the community, overall complication rates are higher than reported by NASCET. One report suggests that endarterectomy in high-risk patients may have a stroke risk of up to 18% (3). Progressive advances in catheter-based techniques and equipment have led to active pursuit of alternative endovascular approaches to carotid stenosis that might offer the same efficacy as carotid endarterectomy with less morbidity. Carotid artery balloon angioplasty and stenting (CABAS) may be such an approach. Theoretical advantages of CABAS include