Comprehensive Cardiovascular Medicine in the Primary Care Setting by Peter P. Toth & Christopher P. Cannon

Author:Peter P. Toth & Christopher P. Cannon
Language: eng
Format: epub
Publisher: Humana Press, Totowa, NJ

15.4 Carotid Endarterectomy in Patients with Symptomatic Carotid Stenosis

The superiority of CEA over medical treatment in the management of symptomatic high-grade carotid artery stenosis has been established in two, large randomized trials: the North American Symptomatic Carotid Endarterectomy Trial (NASCET) (3) and the European Carotid Surgery Trial (ECST) (15). A third trial was stopped prematurely when the results of NASCET were announced (16).

In NASCET and ECST, all surgeons were screened for an acceptable operative record. Entry criteria for these trials included carotid artery stenosis (>30% reduction in the luminal diameter on conventional angiogram) and ipsilateral TIA, non-disabling stroke, or retinal infarction within 4–6 months. The main exclusion criteria included a probable cardiac source of embolism, serious disease likely to cause death within 5 years, or intracranial disease that was more significant than the carotid lesion. Both trials used different methods to measure carotid stenosis. While NASCET used the residual lumen diameter at the most stenotic portion of the vessel and compared this to the lumen diameter in a normal portion of the internal carotid artery distal to the stenosis to determine the degree of stenosis, ECST used the lumen diameter at the most stenotic portion of the vessel and compared this to the estimated probable original diameter at the most stenotic portion of the vessel. In the meantime, equivalent measurements for the two methods have been determined: a 50% stenosis with the NASCET method is equivalent to a 75% for ECST and a 70% stenosis with the NASCET method is equivalent to an 85% stenosis for ECST.

In NASCET and for patients with symptomatic carotid stenosis of 70–99% (measured by the NASCET method), CEA reduced the 2-year risk of ipsilateral stroke from 26% in the medical group (n = 331) to 9% in the surgical group (n = 328), yielding an absolute risk reduction of 17% (p < 0.001). The number needed to treat (NNT) to prevent one stroke was 6 (NNT = 12 at 1 year). A 5.8% incidence of perioperative stroke or death was reported for patients in the surgical arm. In patients with moderate degrees of stenosis (50–69%), the 5-year ipsilateral stroke risk was 22.2% in the medical arm and 15.7% in the surgical arm (p < 0.045). The NNT to prevent one stroke was 15 (NNT = 77 at 1 year). Benefit in the 50–60% stenosis group was best achieved in patients presenting with hemispheric, not retinal symptoms, with stroke rather than TIA, male sex, and intracranial carotid artery stenosis. In this group of patients, subgroup analysis did not demonstrate a benefit of CEA in women (NNT = 125 to prevent one major ipsilateral stroke in 5 years). Patients with <50% stenosis did not benefit from surgery.

The ECST reported a similar efficacy of CEA in the secondary prevention of stroke for patients with a high-grade carotid stenosis. In this trial, the frequency of a major stroke or death at 3 years was 26.5% in the control group (n = 220) versus 14.9% in the surgical group (n = 356), so that surgery was associated with an absolute benefit of 11.

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