Optimal cut-off criteria for duplex ultrasound compared with computed tomography angiography for the diagnosis of restenosis in stented carotid arteries in the international carotid stenting study

Abstract

Introduction: Previous studies that reported duplex-ultrasound cut-off criteria, based on blood velocity parameters, for the degree of stenosis in a stented carotid artery were either retrospective, or the reference test was carried out only when a patient was suspected of having restenosis at duplex ultrasound, which is likely to have resulted in verification bias. We performed a prospective study of diagnostic accuracy to find new blood velocity cut-offs in duplex ultrasound for in-stent restenosis. Patients and methods: Stented patients within the international carotid stenting study were eligible. Patients had a carotid computed tomography angiography in addition to routine duplex ultrasound performed at a yearly follow-up. Duplex-ultrasound bloodflow velocity parameters were compared to the degree of stenosis on computed tomography angiography. The results were analysed using receiver-operating-characteristic curves. Results: We included 103 patients in this study. On computed tomography angiography, 30 (29.1%) patients had a 30%-49% in-stent restenosis, 21 (20.4%) patients had 50%-69% in-stent restenosis and 5 (4.9%) patients a 70% in-stent restenosis. The cut-off value 50% stenosis was a peak systolic velocity of 125 cm/s (sensitivity: 63% (95% CI: 41-79), specificity: 83% (95% CI: 72-90)). Discussion: This study provides a level 2b evidence for new cut-off values for in-stent restenosis. Unfortunately, we could not say anything about severe stenosis because of the low number of severe stenosis after one year. Conclusions: The 125 cm/s cut-off value on duplex ultrasound is lower than found in previous studies and equal to unstented arteries. Duplex-ultrasound measurements made in stented carotid arteries should not be corrected for the presence of a stent when determining the degree of stenosis.

Restenosis and risk of stroke after stenting or endarterectomy for symptomatic carotid stenosis in the International Carotid Stenting Study (ICSS): secondary analysis of a randomised trial

“… 17 , 18 However, in ICSS, a comparison was done of duplex ultrasound velocities and degree of restenosis determined by CTA in a subset of 103 patients treated with stents. 14 The optimum cutoff for peak systolic velocity in the internal carotid artery was greater than 1·25 m/s, which is similar to that used in our study for identifying moderate or higher (≥50%) restenosis. Hence, we used the same standardised velocity criteria in both treatment groups in this current analysis.…”

“… 13 No correction was made for the presence of a stent when measuring stenosis, based on the results of a study of a subset of patients treated with stents in ICSS, which showed similar estimates of stenosis severity from simultaneous CTA and duplex ultrasound examinations. 14 Ultrasound velocity measurements were not available from a few study centres; in these cases, we used the percentage stenosis reported by the local ultrasonographer and investigator. Additional carotid ultrasound and other imaging studies (eg, MRA or CTA) could be done if needed outside the regular follow-up intervals—eg, if patients had recurrent cerebrovascular events.…”

In vitro performance of echoPIV for assessment of laminar flow profiles in a carotid artery stent

“…However, there is also no definition of such a deviation or correction factor for clinical Duplex in carotid stents. Some studies showed increased peak systolic velocities in the stent, [44][45][46] whereas others showed no difference 47 or stent-dependent deviations. 48 A large variance in contrast is visible in measurements 5A and 5C of the transmit voltage subcategory, with standard deviations of 1.25 and 1.59 dB, respectively (Fig.…”

Editor's Choice – Management of Atherosclerotic Carotid and Vertebral Artery Disease: 2017 Clinical Practice Guidelines of the European Society for Vascular Surgery (ESVS)

“…373,374 However, the need to use higher PSV thresholds for diagnosing >50% ICA restenoses after CAS was not confirmed in a recent substudy from ICSS. 375 DUS surveillance enables monitoring of disease progression in the contralateral ICA, which is more common than ipsilateral restenosis, with progression being dependent on disease severity at the time of CEA. The data are, however, conflicting as to its benefit.…”