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

Accuracy of duplex ultrasonography versus angiotomography for the diagnosis of extracranial internal carotid stenosis

INTRODUCTION

Internal carotid artery (ICA) stenosis causes about 15% of ischemic strokes. Duplex ultrasonography (DUS) is the first line of investigation of ICA stenosis, but its accuracy varies in the literature and it is usual to complement the study with another more accurate exam when faced with significant stenosis. There is a lack of studies that compare DUS with angiotomography (CTA) in the present literature.

METHODS

we performed an accuracy study, which compared DUS to CTA of patients in a tertiary hospital with a maximum interval of three months between tests. Patients were selected retrospectively, and two independent and certified vascular surgeons evaluated each image in a masked manner. When there was discordance, a third evaluator was summoned. We evaluated the diagnostic accuracy of ICA stenosis of 50-94% and 70-94%.

RESULTS

we included 45 patients and 84 arteries after inclusion and exclusion criteria applied. For the 50-94% stenosis range, DUS accuracy was 69%, sensitivity 89%, and specificity 63%. For the 70-94% stenosis range, DUS accuracy was 84%, sensitivity 61%, and specificity 93%. There was discordance between CTA evaluators with a change from clinical to surgical management in at least 37.5% of the conflicting reports.

CONCLUSION

DUS had an accuracy of 69% for stenoses of 50-94% and 84% for stenoses of 70-94% of the ICA. The CTA analysis depended directly on the evaluator with a change in clinical conduct in more than 37% of cases.

Appropriateness of care: Asymptomatic carotid stenosis including transcarotid artery revascularization

Carotid artery stenosis is one of the most common diagnoses treated by vascular specialists in the United States. The optimal management of carotid stenosis remains controversial, however, with notable variation surrounding diagnostic imaging modalities, longitudinal surveillance, medical therapies, and procedural interventions. Data from high-quality randomized controlled trials and observational studies form the foundation for current management paradigms and societal guidelines that inform clinical practice. Presently, a diagnosis of carotid disease is most often established with duplex ultrasound and supplemental cross-sectional imaging using computed tomography or magnetic resonance angiography as needed to provide additional anatomic information. All patients with documented occlusive disease should receive goal-directed medical therapy with antiplatelet agents and a lipid-reduction strategy, most commonly with a statin. Those with severe carotid stenosis and an acceptable life expectancy may be considered for carotid artery revascularization. The proceduralist should optimally consider a shared decision-making approach in which the tradeoffs of revascularization can be carefully considered with the patient to optimize informed therapeutic decision making. In current practice, three distinct procedure options exist to treat carotid artery stenosis, including carotid endarterectomy, transfemoral carotid artery stenting, and transcarotid artery revascularization. It should be noted that each procedure, although often used interchangeably in most clinical settings, carry technical nuances and outcome disparities. In this review, each of these topics are explored and various approaches are outlined surrounding the appropriate use of treatments for patients with asymptomatic carotid artery stenosis.

Procedural Safety Comparison Between Transcarotid Artery Revascularization, Carotid Endarterectomy, and Carotid Stenting: Perioperative and 1-Year Rates of Stroke or Death

Background Transcarotid artery revascularization (TCAR) was approved by the Food and Drug Administration in 2015 for patients with carotid artery stenosis. However, no randomized trial to evaluate TCAR has been performed to date, and previous reports have important limitations. Accordingly, we measured stroke or death after TCAR compared with carotid endarterectomy (CEA) and transfemoral carotid artery stenting (TF-CAS). Methods and Results We used the Vascular Quality Initiative registry to study patients who underwent TCAR, CEA, or TF-CAS from September 2016 to June 2021. Our primary outcomes were perioperative and 1-year stroke or death. We used logistic regression for risk adjustment for perioperative outcomes and Cox regression for risk adjustment for 1-year outcomes. We used a 2-stage residual inclusion instrumental variable (IV) method to adjust for selection bias and other unmeasured confounding. Our instrument was a center's preference to perform TCAR versus CEA or TF-CAS. We performed a subgroup analysis stratified by presenting neurologic symptoms. We studied 21 234 patients who underwent TCAR, 82 737 who underwent CEA, and 14 595 who underwent TF-CAS across 662 centers. The perioperative rate of stroke or death was 2.0% for TCAR, 1.7% for CEA, and 3.7% for TF-CAS (P<0.001). Compared with TCAR, the IV-adjusted odds ratio of perioperative stroke or death for CEA was 0.74 (95% CI, 0.55-0.99) and for TF-CAS was 1.66 (95% CI, 0.99-2.79). Results were similar among both symptomatic and asymptomatic patients. The 1-year rate of stroke or death was 6.4% for TCAR, 5.2% for CEA, and 9.7% for TF-CAS (P<0.001). Compared with TCAR, the IV-adjusted hazard ratio of 1 year stroke or death for CEA was 0.97 (95% CI, 0.80-1.17), and for TF-CAS was 1.45 (95% CI, 1.04-2.02). IV analysis further demonstrated that symptomatic patients with carotid stenosis had the lowest 1-year likelihood of stroke or death with TCAR (compared with TCAR, symptomatic IV-adjusted hazard ratio for CEA: 1.30 [95% CI, 1.04-1.64], and TF-CAS: 1.86 [95% CI, 1.27-2.71]). Conclusions Perioperative stroke or death was greater following TCAR when compared with CEA. However, at 1 year there was no statistically significant difference in stroke or death between the 2 procedures. TCAR performed favorably compared with TF-CAS at both time points. Although CEA remains the gold standard procedure for patients with carotid stenosis, TCAR appears to be a safe alternative to CEA and TF-CAS when used selectively and may be useful when treating symptomatic patients.

Carotid artery duplex velocity criteria might be equivocal after left ventricular assist device implantation

BACKGROUND

Although conventional angiography remains the reference standard for the grading of carotid stenosis, carotid duplex ultrasound (CDUS) is the most commonly used modality for determining the degree of carotid stenosis. The validity of CDUS findings for patients after left ventricular assist device (LVAD) implantation is questionable, because the velocities are often altered secondary to the continuous flow nature of the devices.

METHODS

A retrospective review was performed of all patients who had undergone LVAD implantation from January 2007 to December 2019. All patients who had undergone CDUS before and after LVAD implantation were included. Patients receiving extracorporeal membrane oxygenation, those with unusable carotid imaging studies, and those with internal carotid artery (ICA) occlusion were excluded. The peak systolic velocity (PSV) and end-diastolic velocity (EDV) in the ICA and common carotid artery (CCA) and the ICA/CCA ratios were compared before and after LVAD implantation.

RESULTS

A total of 36 patients (mean age 59 years; 30 men; 6 women) had undergone CDUS both before and after LVAD implantation (mean, 647 days between imaging studies). A total of 61 ICAs had met the criteria for inclusion. Before LVAD, 7 carotid arteries (13%) had had >50% carotid stenosis and 53 (87%) had had 0% to 50% stenosis. The mean changes in the velocities after LVAD were as follows. The ICA PSV had decreased by 6.12 ± 4.34 cm/s, and the ICA EDV had increased by 13.44 ± 4.23 cm/s. The CCA PSV had decreased by 17.22 ± 4.95 cm/s, and the CCA EDV had increased by 10.83 ± 2.59 cm/s. The mean ICA/CCA ratio had increased by 0.18 ± 0.05. All the mean changes in velocity were significant (P < .01), except for the ICA PSV (P = .167). Among four patients with known stenosis of 60% to 69%, the degree of increase in the ICA and CCA EDVs (75.8 and 13.3 cm/s, respectively) was significantly greater than that for patients with <50% or no stenosis. Carotid artery laterality did not significantly affect the differences in mean velocity. Centrifugal LVADs resulted in a significantly larger increase in the ICA EDV compared with axial LVADs (26.0 vs 6.3 cm/s; P < .01).

CONCLUSIONS

LVADs were associated with significant changes in CCA PSV, ICA and CCA EDV, and ICA/CCA ratios. However, the magnitude of these changes in patients with <50% stenosis was minimal and might not be clinically significant. The LVAD type might only have an effect on EDV measurements in the CCA, and the left and right carotid arteries did not appear to have different degrees of change in velocity. The currently used criteria for determining carotid stenosis might result in an under- or overestimation of carotid stenosis in patients with an LVAD.

Natural History of Non-operative Management in Asymptomatic Patients with 70%-80% Internal Carotid Artery Stenosis by Duplex Criteria

OBJECTIVE

Treatment of asymptomatic internal carotid artery (ICA) stenosis, particularly for moderate to severe (70%-80%) disease, is controversial. The goal was to assess the clinical course of patients with moderate to severe carotid stenosis.

METHODS

A single institution retrospective analysis of patients with asymptomatic ICA stenosis identified on duplex ultrasound as moderate to severe (70%-80%) from 2003 to 2018 were analysed. Duplex criteria for 70%-80% stenosis was a systolic velocity of ≥325 cm/s or an ICA:common carotid artery ratio of ≥4, and an end diastolic velocity of <140 cm/s. Asymptomatic status was defined as no stroke/transient ischaemic attack (TIA) within six months of index duplex. Primary outcomes were progression of stenosis to >80%, ipsilateral stroke/TIA without documented progression, and death.

RESULTS

In total, 206 carotid arteries were identified in 182 patients meeting the inclusion criteria. Mean patient age was 71.5 years, 57.7% were male, and 67% were white. There were 19 stenoses removed from analysis except for survival analysis as they initially underwent carotid endarterectomy or carotid artery stent based on surgeon/patient preference. Documented progression occurred in 24.1% of stenoses. There were 5.3% of stenoses associated with an ipsilateral stroke/TIA without documented progression, which occurred at a mean of 26.4 months. Kaplan-Meier analysis demonstrated a 60.3% five year freedom from stenosis progression, 92.5% five year freedom from stroke/TIA without documented progression, and 83.7% five year survival. Risk factors associated with stroke/TIA without documented progression at five years were atrial fibrillation (hazard ratio [HR] 14.87, 95% confidence interval [CI] 2.72-81.16; p = .002) and clopidogrel use at index duplex (HR 6.19, 95% CI 1.33-28.83; p = .020). Risk factors associated with death at five years were end stage renal disease (HR 9.67, 95% CI 2.05-45.6; p = .004), atrial fibrillation (HR 7.55, 95% CI 2.48-23; p < .001), prior head/neck radiation (HR 6.37, 95% CI 1.39-29.31; p = .017), non-obese patients (HR 5.49, 95% CI 1.52-20; p = .009), and non-aspirin use at index duplex (HR 3.05, 95% CI 1.12-8.33; p = .030).

CONCLUSION

Patients with asymptomatic moderate to severe carotid stenosis had a low rate of stroke/TIA without documented progression. However, there was a high rate of stenosis progression reinforcing the need to follow these patients closely.