North American Symptomatic Carotid

More recent reports conclude that early CEA after a nondisabling ischemic stroke can be performed with perioperative mortality and stroke rates comparable to those of delayed CEA. In a subgroup analysis by the North American Symptomatic Carotid Endarterectomy Trial (NASCET) investigators, 42 patients who underwent early CEA (<30 days after stroke) were compared with 58 patients who underwent delayed CEA (>30 days), and no overall difference was demonstrated in the perioperative stroke rate (4.8% vs. 5.2%). Another recent prospective randomized study of 86 patients showed no difference in either perioperative stroke (2% in both groups) or survival rates (mean 23 months follow-up) between patients randomized to early or delayed CEA. ... 

Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators. N Engl J Med 1991 325 445 53. 

Gasecki AP, Eerguson GG, EUasziw M, Clagett GP, Pox AJ, Hachinski V, Barnett HJ. Early endarterectomy for severe carotid artery stenosis after a nondisabling stroke Results from the North American symptomatic carotid endarterectomy trial. J Vase Surg 1994 20 288-295. 

Barnett HJ, Taylor DW, Eliasziw M, Fox AJ, Ferguson GG, Haynes RB, Rankin RN, Clagett GP, Hachinski VC, Sackett DL, Thorpe KE, Meldrum HE, Spence JD. Benefit of carotid endarterectomy in patients with symptomatic moderate or severe stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators. N Engl J Med 1998 339(20) 1415-1425. 

I I Paciaroni M, Eliasziw M, Kappelle LJ, Finan JW, Ferguson GG, Barnett HJ. Medical complications associated with carotid endarterectomy. North American Symptomatic Carotid Endarterectomy Trial (NASCET). Stroke 1999 30 1759-1763. 

Ferguson GG, Eliasziw M, Barr HW, et al. The North American Symptomatic Carotid Endarterectomy Trial surgical results in 1415 patients. Stroke 1999 30 1751 -1758. 

Eliasziw M, Smith RE Singh N, Holdsworth DW, Fox AJ, Barnett HJ. Further comments on the measurement of carotid stenosis from angiograms. North American Symptomatic Carotid Endarterectomy Trial (NASCET) Group. Stroke 1994 25 2445-2449. 

Table 18.2. The relationship between aspirin dose and the risk of stroke and death within 30 days of carotid endarterectomy in a non-randomized comparison within the North American Symptomatic Carotid Endarterectomy Trial (Barnett et al. 1998) and in a subsequent randomized controlled trial (Taylor et al. 1999)...

As a result of the large randomized controlled trials, it is now clear that endarterectomy of recently symptomatic severe carotid stenosis almost completely abolishes the high risk of ischemic stroke ipsiiaterai to the operated artery over the subsequent two or three years (see Ch. 27 for detailed discussion of the selection of patients for surgery). Moreover, this effect is durable over at least 10 years (European Carotid Surgery Trialists Collaborative Group 1991, 1998 Mayberg et al. 1991 North American Symptomatic Carotid Endarterectomy Trial Collaborators 1991 Barnett et al. 1998 Rothwell et al. 2003). Indeed, the ipsiiaterai stroke risk becomes so low that presumably both embolic and low-flow strokes are being prevented (Fig. 25.1). 

Fig. 27.2. A selective catheter aragiogram of the carotid bifurcation showing a 90% stenosis. To calculate the degree of stenosis, the lumen diameter at the point of maximum stenosis (A) was measured as the numerator in both the European Carotid Surgery Trial (ECST) method and the North American Symptomatic Carotid Endarterectomy Trial (NASCET) method. However, the NASCET used the lumen diameter of the distal internal carotid artery (B) as the denominator, whereas the ECST used the estimated normal lumen diameter (dotted lines) at the point of maximum stenosis.

Fig. 27.6. A model derived from the data from the Furopean Carotid Surgery Trial (ESCT) for the five-year risk of ipsilateral risk of ischemic stroke on medical treatment tested on data from the North American Symptomatic Carotid Endartereaomy Trial (NASCET). The closed squares show the risk of stroke in the medical treatment group in NASCET, stratified into quintiles on the basis of predicted risk. The open diamonds show the operative risk of stroke and death in the surgical group in NASCET stratified by their predicted medical risk.

Ascher E, Markevich N, Hingorani A et al. (2002). Pseudo-occlusions of the internal carotid artery a rationale for treatment on the basis of a modified duplex scan protocol. Journal of Vascular Surgery 35 340-350 Barnett HJM, Taylor DW, Eliasziw M for the North American Symptomatic Carotid Endarterectomy Trial Collaborators (1998). 

Inzitari D, Eliasziw M, Gates P for the North American Symptomatic Carotid Endarterectomy Trial Group (2000). The causes and risk of stroke in patients with asymptomatic internal-carotid-artery stenosis. New England Journal of Medicine 342 1693-1700... 

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