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Preventing carotid occlusion might not be reason for stenting

Preventive benefits of stenting in asymptomatic carotid stenosis no longer outweigh risks, study suggests

Louise Prime

Tuesday, 22 September 2015

Preventing carotid occlusion might not be a valid indication for stenting in people with asymptomatic carotid stenosis, researchers have argued. Their study,* published this week in JAMA Neurology, showed that the risk of progression to carotid occlusion was well below the risk of carotid stenting or endarterectomy and has decreased markedly with more intensive medical therapy for carotid stenosis. But commentators urged caution, partly because the aggressive medical management in the study clinic may not be the norm in community practice, and because the study had other limitations.

Researchers in Ontario, Canada, analysed data on 3,681 people with asymptomatic carotid stenosis who attended stroke prevention clinics from 1990-95 or 1995-2012. Patients’ mean age was 66 years, most were men, and most had hypertension and hyperlipidaemia.

The study authors looked at ipsilateral stroke, transient ischaemic attack (TIA), death from ipsilateral stroke and death from unknown cause. They found that 316 people had been asymptomatic before the index occlusion, and 254 of these new occlusions occurred before 2002, when medical therapy was less intensive. They reported: “Only 1 patient (0.3%) had a stroke at the time of the occlusion, and only 3 patients (0.9%) had an ipsilateral stroke during follow-up (all before 2005). In Kaplan-Meier survival analyses, neither severity of stenosis nor contralateral occlusion predicted the risk of ipsilateral stroke or transient ischemic attack, death from stroke, or death from unknown cause at a mean follow-up of 2.56 years.”

They pointed out that although mortality is high among people with carotid stenosis, most of the deaths are from causes other than stroke – and these outcomes would not be prevented by carotid stenting or endarterectomy.

They recognised limitations of their study, including the lack of brain imaging unless patients had a stroke, and that they did not study patients who had interventions as a result of becoming symptomatic. Nevertheless, they concluded: “The risk of ipsilateral stroke at the time of carotid occlusion was well below the risk of carotid stenting or carotid endarterectomy, and the percent stenosis or contralateral occlusion did not identify patients who would benefit from intervention. Preventing carotid occlusion may not be a valid indication for intervention.”

The authors of a related editorial** acknowledged that this research adds “some ‘fuel to the fire’ regarding the debate concerning the best treatment for asymptomatic carotid stenosis.” But they cautioned that as a single-centre study, the analysis has limitations, all of which could have led to underestimations in the risk of stroke. They concluded: “Ultimately, whether the improvements in aggressive medical therapy are sufficient to reduce the rationale for CEA (carotid endarterectomy) or CAS (carotid artery stenting) in asymptomatic patients will need to be determined by contemporary randomised clinical trials.”

* Yang C, Bogiatzi C, Spence JD. Risk of stroke at the time of carotid occlusion. JAMA Neurol. Published online 21 September 2015. doi:10.1001/jamaneurol.2015.1843

** Chaturvedi S, Sacco RL. Are the current risks of asymptomatic carotid stenosis exaggerated? JAMA Neurol. Published online 21 September 2015. doi:10.1001/jamaneurol.2015.2196

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