Regarding Comparison of Recent Practice Guidelines for the Management of Patients with Asymptomatic Carotid Stenosis

Abstract

We would like to alert readers to factual errors and omissions in a review recently published in Angiology by Paraskevas et al that may encourage continued overuse of invasive carotid artery procedures. 1 Further, most of these exist in other reviews as specifically indicated below. 2,3 1. A flawed interpretation is that some recent guidelines are suitably more restrictive in endorsing 'revascularisation' procedures for asymptomatic carotid stenosis (ACS) patients by specifying, 4,5 or at least considering, 6 so-called 'high stroke risk' features. [1][2][3] Superficially, this may seem reasonable. However, those so-called high stroke risk features have not been proven in the context of current, optimal, medical intervention (lifestyle coaching and medication) and not all have been identified as high stroke risk markers. 7,8 As a group they cover just about all ACS patients, and often individual markers alone are far too common to identify those likely to benefit from a carotid procedure. 7,8 In effect, recent guidelines 4-6,9 can be used to justify a carotid procedure on just about anyone with advanced ACS. 7,8,10 Further, the authors did not mention the highest absolute annual ipsilateral stroke rate (∼3%) in the meta-analysis by Howard et al, which examined stroke rate according to ACS degree. 1,11 Absolute annual event rates are much more informative than odds or hazards ratios. Stroke rates in the metaanalysis by Howard et al are not reflective of current best (or 'intensive') medical intervention. 1,3,11 We can expect to significantly lower this ipsilateral stroke rate, to 1.5% or less. 12 2. The authors did not acknowledge that the only ACS patients ever to significantly benefit in randomised trials from carotid endarterectomy (CEA) compared to medical intervention alone were highly selected men aged <75-80 years and that the stroke risk reduction benefit for them was small (1%/year). 1-3 Moreover, it was not acknowledged that evidence for this CEA benefit no longer exists due to marked

Fighting Windmills With Asymptomatic Carotid Stenosis

“…5 Furthermore, a recent single-center study of a large academic institution in Southeastern United States reported a 2-year incidence of cerebrovascular events (stroke and transient ischemic attack [TIA]) as high as 11.5%. 6 Although it can be argued that the quality of medically intervention received by the AsxCS patients in this study was incompletely documented or that it did not address all risk factors, this pragmatic report suggests that ipsilateral annual TIA and stroke rates in patients with >70% AsxCS are not as low in “real-life” conditions as supported by Abbott et al 1 Finally, a 2021 population-based cohort study (Oxford Vascular Study) and a systematic review and meta-analysis demonstrated that the 5-year ipsilateral stroke risk for patients with AsxCS varied by the degree of stenosis from 0% for patients with 50–69% AsxCS to 14.6% for individuals with 70–99% AsxCS and up to 18.3% for patients with 80–99% AsxCS. 7 The oversimplification claimed by Abbott et al 1 that “ average annual ipsilateral stroke rates approximate only .8% with nonprocedural management ” is therefore not supported by any independent data.…”

“…and meta-analysis demonstrated that the 5-year ipsilateral stroke risk for patients with AsxCS varied by the degree of stenosis from 0% for patients with 50-69% AsxCS to 14.6% for individuals with 70-99% AsxCS and up to 18.3% for patients with 80-99% AsxCS. 7 The oversimplification claimed by Abbott et al 1 that "average annual ipsilateral stroke rates approximate only .8% with nonprocedural management" is therefore not supported by any independent data.…”

“…Finally, the authors state that “ there is no current randomized evidence of carotid artery procedural benefit compared to medical intervention alone. ” 1 Although this is true, neither is there any RCT evidence showing that BMT alone is superior to a carotid intervention plus BMT for AsxCS patients. Therefore, making an argument for BMT alone for all AsxCS patients is unbalanced and not supported by any RCT evidence.…”

“…Abbott et al 1 claim that they wish to “ alert readers to factual errors and omissions ” in our recently published review. 2 They support that the “high-risk criteria” defined by the 2017 European Society for Vascular Surgery guidelines 3 as imaging/clinical characteristics that may be associated with an increased risk for late ipsilateral stroke in patients with asymptomatic carotid stenosis (AsxCS) have not been tested in randomized controlled trials (RCTs).…”

“…Abbott et al claim that the average annual ipsilateral stroke rates in AsxCS patients approximate only .8% with nonprocedural management. 1 Such low average annual ipsilateral stroke rates may be possible in patients with moderate AsxCS. It is of interest that an earlier prospective international cohort study (where Dr. Abbott is a co-author), the Asymptomatic Carotid Stenosis and Risk of Stroke (ACSRS) study including 1121 AsxCS patients followed up for a mean 4 years demonstrated that the average annual ipsilateral stroke rates in AsxCS actually varied from 0% to 3.1%.…”