Carotid endarterectomy should not be based on consensus statement duplex velocity criteria

Abstract

Objective Randomized trials support carotid endarterectomy (CEA) in asymptomatic patients with ≥60% internal carotid artery (ICA) stenosis. The widely referenced Society for Radiologists in Ultrasound Consensus Statement on carotid duplex ultrasound (CDUS) imaging indicates that an ICA peak systolic velocity (PSV) ≥230 cm/s corresponds to a ≥70% ICA stenosis, leading to the potential conclusion that asymptomatic patients with an ICA PSV ≥230 cm/s would benefit from CEA. Our goal was to determine the natural history stroke risk of asymptomatic patients who might have undergone CEA based on consensus statement PSV of ≥230 cm/s but instead were treated medically based on more conservative CDUS imaging criteria. Methods All patients who underwent CDUS imaging at our institution during 2009 were retrospectively reviewed. The year 2009 was chosen to ensure extended follow-up. Asymptomatic patients were included if their ICA PSV was ≥230 cm/s but less than what our laboratory considers a ≥80% stenosis by CDUS imaging (PSV ≥430 cm/s, end-diastolic velocity ≥151 cm/s, or ICA/common carotid artery PSV ratio ≥7.5). Study end points included freedom from transient ischemic attack (TIA), freedom from any stroke, freedom from carotid-etiology stroke, and freedom from revascularization. Results Criteria for review were met by 327 patients. Mean follow-up was 4.3 years, with 85% of patients having >3-year follow-up. Four unheralded strokes occurred during follow-up at <1, 17, 25, and 30 months that were potentially attributable to the index carotid artery. Ipsilateral TIA occurred in 17 patients. An additional 12 strokes occurred that appeared unrelated to ipsilateral carotid disease, including hemorrhagic events, contralateral, and cerebellar strokes. Revascularization was undertaken in59patients,1 for stroke,12for TIA, and 46 for asymptomatic disease. Actuarial freedom from carotid etiology stroke was 99.7%, 98.4%, and 98.4% at 1, 3, and 5 years, respectively. Freedom from TIA was 98%, 96%, and 95%, freedom from any stroke was 99%, 96%, and 93%, and freedom from revascularization was 95%, 86%, and 81% at 1, 3, and 5 years, respectively. Conclusions Patients with intermediate asymptomatic carotid stenosis (ICA PSV 230-429 cm/s) do well with medical therapy when carefully monitored and intervened upon using conservative CDUS criteria. Furthermore, a substantial number of patients would undergo unnecessary CEA if consensus statement CDUS thresholds are used to recommend surgery. Current velocity threshold recommendations should be re-evaluated, with potentially important implications for upcoming clinical trials.

Regarding “Carotid endarterectomy should not be based on consensus statement duplex criteria”

“…Two recent meta-analyses investigated the risks and benefits of heparin reversal by protamine after carotid endarterectomy (CEA). 1,2 They found that heparin reversal with protamine reduces the risk for reoperation due to bleeding without an increased risk of stroke, myocardial infarction, or death. Yet, we would like to address the hemostatic and hemodynamic effects of protamine.…”

“…Columbo and colleagues reported a favorable prognosis for medically managed patients with evidence of an internal carotid artery stenosis between 70% and 80% on ultrasound. 1 However, there is no evidence that neurologic risk is higher in patients above 80% stenosis than in those with stenosis between 70% and 80%. We believe other parameters that can be obtained from transcranial Doppler ultrasound may be more useful in identifying those patients at risk of stroke who would benefit from carotid endarterectomy.…”

Duplex velocity criteria for carotid endarterectomy

“…3 Up to 90% of CEAs are performed on asymptomatic patients in the United States, in stark contrast to Canada and Europe, where 70% or fewer CEAs are performed on asymptomatic patients (eg, 40.4% in Switzerland, 16.8% in the United Kingdom, 0.0% in Denmark). 4 In their article, Columbo et al 5 derive recommendations from their data that, if followed, would change practice in the United States. Their results and their recommendations raise questions about how asymptomatic patients are diagnosed and treated in this country.…”

“…The foundation for diagnosis in the Columbo study 5 is carotid duplex ultrasound examination, as it was for the Asymptomatic Carotid Atherosclerosis Study (ACAS) and for the Carotid Revascularization Endarterectomy vs Stenting Trial (CREST). In those trials, attempts were not made to include an intermediate stenosis group or exclude a more severe stenosis group.…”

“…Even with defining trial eligibility by a single set of ultrasound criteria, ACAS centers demonstrated poor angiographic-ultrasound agreement. 6 Columbo et al 5 chose to draw a finer diag-nostic point, to distinguish 70% to 79% stenosis from ≥80% stenosis and to define their patient groups accordingly. In the average man, this would be differentiating a residual lumen of 1.5 to 1.1 mm from a residual lumen of ≤1 mm, the difference being 0.5 mm or about one-third the thickness of a dime.…”