Extra-Cranial Carotid Artery Stenosis: An Objective Analysis of the Available Evidence

Abstract

Background and PurposeCarotid stenosis is arterial disease narrowing of the origin of the internal carotid artery (main brain artery). Knowing how to best manage this is imperative because it is common in older people and an important cause of stroke. Inappropriately high expectations have grown regarding the value of carotid artery procedures, such as surgery (endarterectomy) and stenting, for lowering the stroke risk associated with carotid stenosis. Meanwhile, the improving and predominant value of medical intervention (lifestyle coaching and medication) continues to be underappreciated.Methods and ResultsThis article aims to be an objective presentation and discussion of the scientific literature critical for decision making when the primary goal is to optimize patient outcome. This compilation follows from many years of author scrutiny to separate fact from fiction. Common sense conclusions are drawn from factual statements backed by original citations. Detailed research methodology is given in cited papers. This article has been written in plain language given the importance of the general public understanding this topic. Issues covered include key terminology and the economic impact of carotid stenosis. There is a summary of the evidence-base regarding the efficacy and safety of procedural and medical (non-invasive) interventions for both asymptomatic and symptomatic patients. Conclusions are drawn with respect to current best management and research priorities. Several “furphies” (misconceptions) are exposed that are commonly used to make carotid stenting and endarterectomy outcomes appear similar. Ongoing randomized trials are mentioned and why they are unlikely to identify a routine practice indication for carotid artery procedures. There is a discussion of relevant worldwide guidelines regarding carotid artery procedures, including how they should be improved. There is an outline of systematic changes that are resulting in better application of the evidence-base.ConclusionThe cornerstone of stroke prevention is medical intervention given it is non-invasive and protects against all arterial disease complications in all at risk. The “big” question is, does a carotid artery procedure add patient benefit in the modern era and, if so, for whom?

Words of Caution Regarding Safety Comparisons Between Transcarotid Artery Revascularization, Carotid Endarterectomy, and Carotid Stenting

“…In addition, both TCAR and CEA appeared to be less hazardous than CAS at both time points, consistent with the existing evidence base demonstrating excess hazards of CAS compared with CEA. 2 , 3 , 4 …”

“…5 , 6 , 7 , 8 , 9 Of note, the overall average annual stroke risk reduction benefit from CEA in these randomized trials was small: ≈1% for asymptomatic carotid stenosis patients and up to ≈3.2% for symptomatic patients with ipsilateral carotid stenosis. 2 …”

“…The patient subgroups with carotid stenosis with an overall benefit from CEA in the above‐mentioned randomized trials (or with an overall benefit from early versus deferred CEA 10 ) had to satisfy all trial selection criteria, have a life expectancy of at least 3 to 5 years, and fit into 1 of the 4 following groups 1 , 2 : Men aged <75 to 80 years with 60% to 99% asymptomatic (or recently asymptomatic) carotid stenosis (by way of conventional intra‐rterial angiography or ultrasound and NASCET [North American Symptomatic Carotid Endarterectomy Trial] criteria) 5 , 7 , 10 Symptomatic women with 70% to 99% stenosis (by way of conventional intra‐arterial angiography and NASCET criteria) having CEA within 2–3 weeks of their last same‐sided nonsevere stroke or transient ischemic attack. 7 , 8 , 9 Symptomatic men with 50% to 69% stenosis (by way of conventional intra‐arterial angiography and NASCET criteria) having CEA within 2 to 3 weeks of their last same‐sided nonsevere stroke or transient ischemic attack.…”

“…Moreover, past randomized trials of CEA versus noninvasive medical intervention alone have been increasingly outdated since they were started because of continuing improvement in the stroke prevention effectiveness of noninvasive medical intervention. 2 This means that there is no current trial evidence of benefit from any form of carotid artery procedure in any subgroup of patients with carotid stenosis. The IV analysis methodology is not the same as a randomized trial of appropriate patients, and reasons why proceduralists chose or preferred TCAR, CEA, or CAS were not provided.…”

“… 1 Although results of the analysis by Columbo et al 1 indicate that TCAR is safer than CAS, it is already well established that CEA is safer than CAS with respect to short‐ and long‐term stroke, plus or minus rates of periprocedural death or myocardial infarction. 2 , 3 , 4 Why use a new, alternative procedure, such as TCAR, with its necessary learning curves, when it is not proven to be as safe as or safer than CEA, and TCAR has no proven superior stroke risk reduction benefit compared with current noninvasive medical intervention alone? Guidelines worldwide already encourage use of carotid artery procedures in subgroups not shown to benefit compared with noninvasive medical intervention alone.…”