Ultrasonographic and hemodynamic characteristics of patients with symptomatic carotid near-occlusion: results from a multicenter registry study

Palacios-Mendoza, Michael; García-Pastor, Andrés; Gil‐Núñez, A.; Ramírez-Moreno, J.M.; González-Nafría, Noelia; Moniche, Francisco; Portilla-Cuenca, Juan Carlos; Fuentes, Blanca; Gamero-García, Miguel Ángel; Leciñana, M. Alonso de; Masjuán, Jaime; Cánovas-Vergé, David; Aladro, Yolanda; Lago, Aída; Arce-Borda, Ana María de; Usero-Ruiz, María; Delgado‐Mederos, Raquel; Pampliega, A.; Ximénez-Carrillo, Álvaro; Bártulos-Iglesias, Mónica; Castro-Reyes, Enrique

doi:10.1007/s00234-020-02567-w

Cited by 8 publications

(7 citation statements)

References 23 publications

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“…With the expanded definition of near-occlusion, the sensitivity of commonly used ultrasound parameters for nearocclusion was low, but specificity was high, both in the current study and in Khangure et al, that also used this expanded definition [11]. Similarly, Palacios-Mendoza et al recently confirmed that many near-occlusions are mistaken for conventional stenosis, but provided no velocity data or detailed definition [17]. We found a slightly higher sensitivity for the combined any indication of near-occlusion approach (22%) than Khangure et al (15%) [11].…”

Section: Discussionsupporting

confidence: 41%

Near-occlusion is difficult to diagnose with common carotid ultrasound methods

et al. 2021

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Purpose To assess the sensitivity and specificity of common carotid ultrasound method for carotid near-occlusion diagnosis. Methods Five hundred forty-eight patients examined with both ultrasound and CTA within 30 days of each other were analyzed. CTA graded by near-occlusion experts was used as reference standard. Low flow velocity, unusual findings, and commonly used flow velocity parameters were analyzed. Results One hundred three near-occlusions, 272 conventional ≥50% stenosis, 162 <50% stenosis, and 11 occlusions were included. Carotid ultrasound was 22% (95%CI 14–30%; 23/103) sensitive and 99% (95%CI 99–100%; 442/445) specific for near-occlusion diagnosis. Near-occlusions overlooked on ultrasound were found misdiagnosed as occlusions (n = 13, 13%), conventional ≥50% stenosis (n = 65, 63%) and < 50% stenosis (n = 2, 2%). No velocity parameter or combination of parameters could identify the 65 near-occlusions mistaken for conventional ≥50% stenoses with >75% sensitivity and specificity. Conclusion Near-occlusion is difficult to diagnose with commonly used carotid ultrasound methods. Improved carotid ultrasound methods are needed if ultrasound is to retain its position as sole preoperative modality.

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Section: Discussionsupporting

confidence: 41%

Near-occlusion is difficult to diagnose with common carotid ultrasound methods

et al. 2021

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“…In a SPECT study with 15 near-occlusions, some near-occlusions had exhausted cerebrovascular reserve, some just reduced, but the analysis did not distinguish between symptomatic and asymptomatic near-occlusion or between with and without full collapse [5]. In a TCD study, with 50 symptomatic near-occlusions, 22 (44%) had reduced and 11 (22%) had exhausted cerebrovascular reserve, with similar findings for with and without full collapse [6]. In contrast, Greiner et al briefly reported that among 53 near-occlusions (seemingly all with full collapse), the cerebrovascular reserve was always reduced, but never exhausted [9].…”

Section: Discussionmentioning

confidence: 86%

“…The mechanism of the recurrent strokes in near-occlusion with full collapse is unknown. Cerebral hypoperfusion has been proposed [5][6][7]. As ICA diameter is closely linked to ICA flow [8], full collapse causes a large blood flow reduction through the ICA.…”

Section: Discussionmentioning

confidence: 99%

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Symptomatic and asymptomatic carotid near-occlusions have very similar angiographic appearance on CT-angiography

Kellomäki

Fox

et al. 2022

Neuroradiology

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The aim of this study was to compare the angiographic appearance of symptomatic and asymptomatic carotid near-occlusion. We have found no such previous study. The study hypothesis was that among symptomatic patients with ≥ 50% carotid stenosis, near-occlusion is more common and near-occlusions are more severe than among asymptomatic persons with ≥ 50% carotid stenosis. We reassessed consecutive CTAs from 4042 persons, 645 had ≥ 50% carotid stenosis, and 385 (60%) symptomatic. Near-occlusion was similarly common in symptomatic (105, 27%) and asymptomatic (56, 24%) cases. Among near-occlusions, the angiographic appearance was very similar between symptomatic and asymptomatic cases: mean stenosis lumen diameter (0.7 mm), distal ICA diameter (2.1 mm), and ECA ratio (0.79) were the same in both groups. Mean ICA ratio (0.46 and 0.48) and share of full collapse was very similar (45% and 42%). These findings add to the pathophysiological understanding of carotid near-occlusion.

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“…These data are in favor of compensatory mechanisms via collateral pathways in case of carotid stenosis. In a doppler study, CVR tended to be less important in patients without collateral circulation (52). There was a majority of patients with a reduced CVR ipsilateral to carotid stenosis.…”

Section: Influence Of Collateral Circulationmentioning

confidence: 88%

A narrative review of the pathophysiology of ischemic stroke in carotid plaques: a distinction versus a compromise between hemodynamic and embolic mechanism

Mechtouff¹,

Rascle²,

Crespy³

et al. 2021

Ann Transl Med

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Atherosclerotic carotid artery stenosis causes about 10-20% of all ischemic strokes through two main mechanisms: hemodynamic impairment in case of significant stenosis and thromboembolism from an atherosclerotic plaque regardless of the degree of stenosis. The latter is the most frequent mechanism and appear to result from embolization from a vulnerable atherosclerotic plaque or acute occlusion of the carotid artery and propagation of thrombus distally. Downstream infarcts may occur in a territory of major cerebral artery or at the most distal areas between two territories of major cerebral arteries, the so-called watershed (WS), or border zone area. Although WS infarcts, especially deep WS infarct, were historically thought to be due to hemodynamic compromise, the role of microembolism has also been documented, both mechanisms may act synergistically to promote WS infarcts. Routine and more advanced imaging techniques may provide information on the underlying mechanism involved in ipsilateral ischemic stroke. A better understanding of ischemic stroke pathogenesis in carotid stenosis may limit the use of routine non-selective shunt, whose benefit-risk balance is debated, to patients with hemodynamic impairment.After reviewing existing evidence underpinning the contribution of the two mechanisms in downstream ischemic stroke and the various imaging techniques available to investigate them, we will focus on the pathogenesis of WS infarcts that remains debated.

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Ultrasonographic and hemodynamic characteristics of patients with symptomatic carotid near-occlusion: results from a multicenter registry study

Cited by 8 publications

References 23 publications

Near-occlusion is difficult to diagnose with common carotid ultrasound methods

Near-occlusion is difficult to diagnose with common carotid ultrasound methods

Symptomatic and asymptomatic carotid near-occlusions have very similar angiographic appearance on CT-angiography

A narrative review of the pathophysiology of ischemic stroke in carotid plaques: a distinction versus a compromise between hemodynamic and embolic mechanism

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