Benefit of carotid endarterectomy for symptomatic and asymptomatic severe carotid artery stenosis: a Markov model based on data from randomized controlled trials
Clinical article
Object
Several major randomized controlled trials of carotid endarterectomy (CEA) in patients with both symptomatic and asymptomatic carotid artery stenosis have addressed the net effects of CEA on the risk of stroke. However, because the risk of stroke among patients with asymptomatic carotid stenosis is relatively low, whether to treat their stenosis with CEA remains an important public health issue.
Methods
The authors constructed a Markov model to evaluate the effectiveness of CEA. In modeling 4 health states, the probability of transition to another state was estimated using data from major randomized controlled trials. Adopting 3 comorbidity index values for baseline analyses, the authors expressed outcomes in terms of the expected number of quality-adjusted life years (QALYs) for a hypothetical cohort undergoing CEA and another without treatment.
Results
In the authors' baseline analysis, CEA for asymptomatic stenosis yielded a very small benefit (0.07 QALY) for 70-year-old, normal-risk CEA candidates. Benefits decreased further, often becoming negative, as patient age, surgical risk, or comorbidity index increased. In patients with symptomatic stenosis, CEA was always more effective than conservative management, even considering variables such as comorbidities limiting life expectancy, advanced age, and increased perioperative risk.
Conclusions
Carotid endarterectomy for severe carotid stenosis consistently and significantly benefits patients with recent symptoms. However, surgery for asymptomatic stenosis appears justified only in carefully selected conditions: low treatment risks in relatively young individuals without any comorbidities.
Abbreviations used in this paper:
ACAS = Asymptomatic Carotid Atherosclerosis Study; CA = carotid artery; CAS = carotid angioplasty and stenting; CEA = carotid endarterectomy; QALY = quality-adjusted life year; RCT = randomized controlled trial.
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