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Best Suited for Stenting versus Endarterectomy. The Controversial Issue

Few procedures in the history of medicine have been as controversial as carotid stenting is as an alternative to endarterectomy in patients with carotid artery occlusive disease. This has been justifiable considering that endarterectomy has represented the gold standard in management of occlusive carotid artery disease since 1976. In contrast, the technology for carotid stenting is in constant evolution, as continual improvement in the technology occurs. This has been most apparent in the utilization of distal protection filter devices, proximal flow control devices, and the changing cell geometry in selfexpanding nitinol stents. Patient outcomes have also improved as we recognize the importance of operator experience and careful patient selection. In an attempt to improve outcomes, we developed a lesion classification based on angiographic features. These were divided into 3 groups of patients. Type A lesions were ,1.5 cm in length, concentric, non-calcified, and without ulceration. Type B lesions were 1.5 to 2 cm in length, with ostial involvement, ulcerations, and stenosis $85%. Type C lesions were .2 cm in length, complex ulceration, calcification, and preocclusive anatomy. Although this classification was helpful, it did not necessarily correlate with procedural strokes. What was missing was the failure to develop criteria ‘‘too high risk for stenting.’’ When the high surgical risk carotid trials were initiated, we presumed we could stent all patients who met the entry criteria. Several problems became apparent. First, we recognize that the complex aortic arch was its own independent stroke risk predictor. Furthermore, octogenarians—both asymptomatic and symptomatic—had unacceptable event rates as high as 13% and 16%, respectively. Since octogenarians represented 25% to 30% of the trial populations, these unfavorable results affected the overall outcome. Although 30-day outcomes of major strokes in essentially all of the trials and registries was #2% and the minor strokes were in the range of 3% to 5%, we were uncertain as to why, where, and how these strokes were occurring. In this issue of the journal, Diethrich et al. for the first time suggest that composition analysis of the plaque may clarify certain of these issues. Intravascular ultrasound with virtual histology provides an analog map of plaque characteristics consisting of fibrous, fibroatheromatous, calcific, and necrotic lipid core components. Understanding these characteristics, the authors suggest that it may be possible to separate those patients best suited for endarterectomy versus stenting. When the lesion characteristics are $30%, with necrotic and calcific core components at the intimal surface, those patients may be better served with endarterectomy. In contrast, however, our experience has shown when fibrous and fibroatheromatous changes exist, those patients tolerate stenting without procedural events.