Carotid Endarterectomy
CEA is perhaps the best-studied surgical procedure, with multiple well-conducted prospective randomized trials demonstrating its efficacy. The procedure had been performed for hundreds of thousands of patients prior to this data being published in the early 1990s. The North American Symptomatic Carotid Endarterectomy Trial (NASCET) was the landmark study demonstrating the efficacy of intervention. The trial of patients with symptomatic carotid stenosis was stopped early for patients with severe stenosis, defined as 70% to 99% narrowing by conventional angiography. At two years, the rate of ipsilateral stroke or post-operative death in patients with severe stenosis decreased from 26% in the medical arm to 9% in the CEA arm [an absolute risk reduction of 17% and number needed to treat of six (p<0.001)].
Rarely has any medical or surgical procedure had such a robust effect over so short an interval for such an important outcome. Patients with less severe stenosis were followed out to five years, with the final results showing benefit among patients with moderate stenosis (50% to 69%).6 The Veterans Affairs Cooperative Trial 309 and the European Carotid Stenosis Trial (ECST) were combined with NASCET in a pooled analysis of more than 6,000 patients and about 35,000 patient-years of follow-up.7-9
Among patients with 70% or greater stenosis, CEA reduced the absolute five-year risk of ipsilateral ischemic stroke and any operative stroke or death by 16% (95% confidence interval 11.2% to 20.8%). The benefit was less pronounced among patients with 50% to 69% stenosis, in whom CEA conferred a 4.6% (95% confidence interval 0.6% to 8.6%) absolute five-year risk reduction.
The medical aspect of these trials required only the use of aspirin. Intensive lipid control and tight glycemic and blood pressure control would probably reduce the rate of events. The 30-day operative risk was consistently less than 6% across these trials, with the benefit seen by two years among patients with 70% to 99% stenosis and by five years among patients with 50% to 69% stenosis.
Referring hospitalists should know the operative event rates of the surgeons to whom they are referring. Hospitalists should also refer those patients whose anticipated life expectancy is at least two years for patients with 70% to 99% stenosis and at least five years for patients with 50% to 69% stenosis.
Figures 1 and 2. ACCUnet Distal Embolic Protection Device, Before and After Carotid Angioplasty and Stenting
Figures 1 and 2. ACCUnet Distal Embolic Protection Device, Before and After Carotid Angioplasty and Stenting
Figures 1 and 2. ACCUnet Distal Embolic Protection Device, Before and After Carotid Angioplasty and Stenting
Carotid Angioplasty and Stenting
CAS is increasingly used as an alternative to CEA among selected patients. Two procedural developments have improved the safety of percutaneous carotid revascularization.
First, distal embolic protection filters deployed prior to angioplasty collect debris associated with the mechanical intervention and limit the risk of peri-procedural stroke. (See Figures 1 and 2, p. 36.)
Second, the use of self-expanding stents has improved long-term patency over balloon-expanding stents, which can be damaged by neck movement and external pressure.
The Stenting and Angioplasty with [distal embolic] Protection in Patients at High Risk for Endarterectomy trial demonstrated the noninferiority of CAS versus CEA among high-risk patients.10 Inclusion criteria were symptomatic carotid stenosis of greater than 50% or asymptomatic stenosis greater than 80%. Patients had to have one of several high-risk features to be included. (See Table 1, above)
The cumulative incidence of post-operative stroke, myocardial infarction, death, and ipsilateral stroke within one year after the procedure was 20.1% in the CEA arm and 12.2% in the CAS arm (p=0.004 for noninferiority and p=0.053 for superiority). The rate of post-procedural cranial nerve injury was substantially lower (zero) in the CEA arm.