A New Doppler-Derived Parameter to Quantify Internal Carotid Artery Stenosis: Maximal Systolic Acceleration

Jeroen J.W.M Brouwers,Janey F.Y Jiang,Robert T Feld,Louk P Van Doorn,Rob C Van Wissen,Marianne A.A Van Walderveen,Jaap F Hamming,Abbey Schepers

doi:10.1016/j.avsg.2021.09.056

Jeroen J.W.M Brouwers, Janey F.Y Jiang + Show 6 more

Open Access

https://doi.org/10.1016/j.avsg.2021.09.056

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Abstract

Doppler ultrasonography (DUS) is used as initial measurement to diagnose and classify carotid artery stenosis. Local distorting factors such as vascular calcification can influence the ability to obtain DUS measurements. The DUS derived maximal systolic acceleration (ACCmax) provides a different way to determine the degree of stenosis. While conventional DUS parameters are measured at the stenosis itself, ACCmax is measured distal to the internal carotid artery (ICA) stenosis. The value of ACCmax in ICA stenosis was investigated in this study. All carotid artery DUS studies of a tertiary academic center were reviewed from October 2007 until December 2017. Every ICA was included once. The ACCmax was compared to conventional DUS parameters: ICA peak systolic velocity (PSV), and PSV ratio (ICA PSV/ CCA PSV). ROC-curve analysis was used to evaluate accuracy of ACCmax, ICA PSV and PSV ratio as compared to CT-angiography (CTA) derived stenosis measurement as reference test. The study population consisted of 947 carotid arteries and was divided into 3 groups: <50% (710/947), 50-69% (109/947), and ≥70% (128/947). Between these groups ACCmax was significantly different. Strong correlations between ACCmax and ICA PSV (R2 0.88) and PSV ratio (R2 0.87) were found. In ROC subanalysis, the ACCmax had a sensitivity of 90% and a specificity of 89% to diagnose a ≥70% ICA stenosis, and a sensitivity of 82% and a specificity of 88% to diagnose a ≥50% ICA stenosis. For diagnosing a ≥50% ICA stenosis the area under the curve (AUC) of ACCmax (0.88) was significantly lower than the AUC of PSV ratio (0.94) and ICA PSV (0.94). To diagnose a ≥70% ICA stenosis there were no significant differences in AUC between ACCmax (0.89), PSV ratio (0.93) and ICA PSV (0.94). ACCmax is an interesting additional DUS measurement in determining the degree of ICA stenosis. ACCmax is measured distal to the stenosis and is not hampered by local distorting factors at the site of the stenosis. ACCmax can accurately diagnose an ICA stenosis, but was somewhat inferior compared to ICA PSV and PSV ratio to diagnose a ≥50% ICA stenosis.

Highlights

Carotid artery stenosis has long been recognized as an important etiological factor for ischemic stroke and large trials have determined the benefit of carotid endarterectomy (CEA) in symptomatic patients as prophylactic countermeasure against stroke.[1,2,3,4,5]
In total 676 patients underwent Doppler ultrasonography (DUS) of the carotid artery, which adds up to 2353 carotid artery measurements, as for some patients multiple DUS were performed during the study period. 1406 carotid arteries were excluded for several reasons mentioned in Figure 2, resulting in 947 carotid arteries available for analysis
A Pearson correlation coefficient (r) of −0.69 was found between ACCmax and internal carotid artery (ICA) peak systolic velocity (PSV)

Summary

Introduction

Carotid artery stenosis has long been recognized as an important etiological factor for ischemic stroke and large trials have determined the benefit of carotid endarterectomy (CEA) in symptomatic patients as prophylactic countermeasure against stroke.[1,2,3,4,5] Doppler ultrasonography (DUS) is the primary evaluation of carotid artery stenosis and management determination.[6,7,8] in many centers additional imaging (computed tomographic angiography (CTA) or MR angiography (MRA)) is obtained when intervention is considered, in some regions a majority of surgical interventions of the carotid artery is based on DUS-imaging alone.[9]. According to the Society of Radiologists in Ultrasound Consensus Conference the evaluation of carotid artery stenosis with DUS-imaging relies on four parameters: peak systolic velocity (PSV) in the internal carotid artery (ICA), optical estimation of the stenosis, PSV ratio (PSV ICA/PSV common carotid artery (CCA)), and the end diastolic velocity (EDV) in the ICA.[8] While these parameters together provide an informative basis to determine and grade a stenosis, all four parameters are measured at the level of the stenosis and can be influenced by local distorting factors. Presence of calcified atherosclerotic plaques and near occlusions can hamper these measurements and potentially lead to inaccurate estimation of degree of ICA stenosis. 8 , 10–13

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