AN ANALYSIS OF PERIOPERATIVE SURGICAL MORTALITY AND MORBIDITY IN THE ASYMPTOMATIC CAROTID ATHEROSCLEROSIS STUDY

Background and Purpose Our aim was to determine the perioperative morb idity and mortality rates of patients in the surgical arm of the multi -institutional, prospective, randomized Asymptomatic Carotid Atheroscl erosis Study (ACAS). Methods Of 828 patients with carotid stenosis of 60% or more randomized to the surgical arm of ACAS, 721 underwent caro tid endarterectomy (CEA). To qualify for participation, surgeons were required to have performed at least 12 CEAs per year with a combined n eurological morbidity and mortality rate no greater than 3% for asympt omatic patients and 5% for symptomatic patients. Clinical centers had to demonstrate arteriographic morbidity less than 1% and mortality les s than 0.1% per year. Primary events were stroke and death in the peri od between randomization and 30 days after surgery; secondary events w ere transient ischemic attack and myocardial infarction occurring in t he same period. Results Of the 721 patients who underwent CEA, 1 died and 10 others had strokes within 30 days (1.5%). Of the 415 who underw ent arteriography after randomization but before CEA, 5 (1.2%) suffere d transient ischemic attack or stroke caused by arteriography. Thus, a nearly equal risk of stroke was associated with both CEA and carotid arteriography. In addition, 6 transient ischemic attacks and 3 myocard ial infarctions could be directly linked to CEA, for a total CEA event rate of 2.6%. Conclusions Patients with asymptomatic internal carotid artery stenosis exceeding 60% reduction in diameter who are acceptabl e candidates for elective operation may be considered for CEA if the c ombined arteriographic and surgical complication rates are 3% or less.