Prevention of functional impairment by endarterectomy for symptomatic high-grade carotid stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators
R. B. Haynes, D. W. Taylor, D. L. Sackett, K. Thorpe, G. G. Ferguson and H. J. Barnett
Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada.
OBJECTIVE--To determine whether carotid endarterectomy prevents
deterioration of functional status among patients with transient ischemic
attacks or nondisabling strokes and ipsilateral carotid stenosis of 70% to
99%. DESIGN--Multicentered randomized controlled trial with an average
18-month follow-up. SETTING--Fifty clinical centers in North America.
PATIENTS--A total of 659 patients presenting with recent transient attacks
of nondisabling stroke and ipsilateral atherosclerotic carotid stenosis of
70% to 99% were included. Patients were stable neurologically at the time
of entry. No patient was lost to follow-up. INTERVENTION--Vascular surgeons
and neurosurgeons were prescreened for low perioperative complication
rates. Patients were randomly allocated to carotid endarterectomy plus
continuing medical care (n = 328) or medical care alone (n = 331),
including antiplatelet therapy. MAIN OUTCOME MEASURES--All patients were
assessed by neurologists for the occurrence of stroke and functional status
at scheduled intervals after entry. RESULTS--In addition to a previously
reported risk reduction for ipsilateral stroke for patients assigned to
carotid endarterectomy, there was an absolute risk reduction (and relative
risk reduction [RRR]) for functional status impairment of 5.6% (RRR, 69%)
for vision, 4.6% (RRR, 87%) for comprehension of language, 8.3% (RRR, 88%)
for fluency of speech, 4.3% (RRR, 84%) for swallowing, 6.0% (RRR, 53%) for
lower-limb function, 9.3% (RRR, 75%) for upper-limb function, 7.4% (RRR,
60%) for shopping, and 10.5% (RRR, 50%) for visiting outside usual
residence (P < .05, two-tailed, for all items). CONCLUSIONS--Carotid
endarterectomy reduced the risk for impairment of function among patients
with recent symptomatic cerebral ischemia and ipsilateral high-grade
carotid stenosis.
