Carotid Near-Occlusion: A Comprehensive Review, Part 2—Prognosis and Treatment, Pathophysiology, Confusions, and Areas for Improvement

Johansson, Elias; Fox, Allan J.

doi:10.3174/ajnr.a4429

Cited by 36 publications

(66 citation statements)

References 51 publications

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“…Several pathophysiological mechanisms have been described [27]. This is the first study to report data using EEG-guided artery clamping in these patients with NOFC.…”

Section: Discussionmentioning

confidence: 99%

Carotid endarterectomy in patients with recurrent symptoms associated with an ipsilateral carotid artery near occlusion with full collapse

et al. 2018

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ObjectiveNear occlusion (NO) of the internal carotid artery (ICA) with full collapse (NOFC) is a rare condition, with a prevalence of around 1%. Guidelines on carotid stenosis recommend a conservative treatment in patients with a single-event ipsilateral to a NOFC, but the optimal treatment for patients with recurrent symptoms associated with NOFC remains uncertain. We describe a consecutive series of patients with recurrent symptoms associated with NOFC (RSNOFC) who underwent carotid endarterectomy (CEA).MethodsFrom 2008 to 2017, 17 consecutive patients with RSNOFC were treated according to our standardized multidisciplinary work-up and protocol and included for this single-center cohort study. NO was defined according to the angiographic North American Symptomatic Carotid Endarterectomy Trial criteria. Only patients with NOFC were included in this study.ResultsStandard longitudinal CEA was performed in 15 patients, whereas in 2 patients the ICA was ligated with concomitant endarterectomy of the ECA. Within 30 postoperative days, one patient died from a hemorrhagic infarction. During follow-up (median 23 months) one patient died of unknown cause 90 days after CEA. No TIA, stroke, myocardial infarction or re-stenosis occurred in the remaining patients.ConclusionIn patients with RSNOFC, CEA may be considered a potential treatment option. Although procedural risks in this small subgroup may be higher as compared to patients with low-to-moderate risk anatomy, this risk may outbalance the natural course.

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“…Several pathophysiological mechanisms have been described [27]. This is the first study to report data using EEG-guided artery clamping in these patients with NOFC.…”

Section: Discussionmentioning

confidence: 99%

Carotid endarterectomy in patients with recurrent symptoms associated with an ipsilateral carotid artery near occlusion with full collapse

et al. 2018

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“…Carotid near-occlusion is a variant of severe carotid stenosis. In contrast to conventional ≥ 50% carotid stenosis, nearocclusion has a reduced artery size ("collapse") distal to the stenosis [1][2][3]. The collapse is a physiological response to reduction in flow.…”

Section: Introductionmentioning

confidence: 99%

Carotid near-occlusion is often overlooked when CT angiography is assessed in routine practice

Johansson

Aviv

et al. 2020

Eur Radiol

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Objective Assess the sensitivity and specificity of computed tomography angiography (CTA) for carotid near-occlusion diagnosis interpreted in clinical practice against expert assessment. Methods CTAs were graded by two expert interpreters for near-occlusion. Findings were compared with clinical reports in 383 consecutive cases with symptomatic ≥ 50% carotid stenosis. In addition, 14 selected CTA exams (8 near-occlusions and 6 controls) were analyzed in a national effort by 13 radiologists experienced with carotid CTA. Results In clinical practice, imaging reports were 20% (95% CI 12-28%) sensitive for near-occlusion, ranging 0-58% between different radiologists; specificity was 99%. Among the 13 radiologists reviewing the same 8 near-occlusions, the average sensitivity was 8%, ranging 0-75%; specificity was 100%.Conclusions Carotid near-occlusion is systematically under-reported in clinical routine practice, caused by limited application of grading criteria when assessing CTA. Key Points • Carotid near-occlusion is severe stenosis with distal artery collapse; this collapse is often subtle.• A fifth of near-occlusions were detected in routine practice. Many readers mistake near-occlusion for stenosis without distal artery collapse, either by not actively searching for subtle collapses or by not interpreting the collapse correctly when noticed. • On the other hand, the novice diagnostician should be cautioned to not over-diagnose near-occlusion; other causes of extracranial ICA asymmetry also exist such as distal disease and Circle of Willis anatomical variants.

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“…Their goal was Bto facilitate the recognition and diagnosis of near-occlusion, and raise the notion that even when a subtle distal ICA LD [Luminal Diameter] reduction is present, a possible near-occlusion should be considered.^It is important to raise awareness of near-occlusions without full collapse, when the distal artery otherwise seems normal, albeit smaller than usual. Indeed, this issue is so important that we recently ranked it as one of the two major near-occlusion issues in most need of improvement [2]. Any neuroradiologist who is not well aware of the near-occlusion without full collapse would do well to apply this as a first step towards improved understanding.…”

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confidence: 99%

Diagnosing carotid near-occlusion with 1 mm side-to-side asymmetry: a tough task made too easy

Johansson

Fox

2017

Neuroradiology

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In this issue of Neuroradiology, Koskinen and colleagues present their idea: that carotid near-occlusion (a tight stenosis that causes a collapse of the distal artery) can be separated from conventional ≥50% stenosis by measuring the distal diameter and all cases with ≥1.0 mm side-to-side difference is a nearocclusion [1]. Their goal was Bto facilitate the recognition and diagnosis of near-occlusion, and raise the notion that even when a subtle distal ICA LD [Luminal Diameter] reduction is present, a possible near-occlusion should be considered.^It is important to raise awareness of near-occlusions without full collapse, when the distal artery otherwise seems normal, albeit smaller than usual. Indeed, this issue is so important that we recently ranked it as one of the two major near-occlusion issues in most need of improvement [2]. Any neuroradiologist who is not well aware of the near-occlusion without full collapse would do well to apply this as a first step towards improved understanding. However, apart from raising initial awareness, we advocate against the use of this proposed 1.0 mm criterion for diagnosing near-occlusion. Interpretative approach to near-occlusion diagnosisCarotid near-occlusion is a pattern-recognition diagnosis where interpretation of multiple key features is at the core of diagnosis [3]. These multiple key features have been presented before [4,5]: for both conventional angiography and CTA, side-to-side ICA difference and similar-sized or smaller ICA than ECA are features; for conventional angiography, delay of contrast and evidence of collaterals are features; and for CTA, absolute ICA size and impressive stenosis are features. BImpressive^stenosis applies to when contrast is hardly (or no longer) seen in the stenosis [4] and remaining features are Bpositive^when visible to the eye of the observer. Studies with sensitivity and specificity of these features have compared to interpretation [4,5]. Hence, a previously reported 0.87 side-to-side ratio was an approximation of what was visible [4]. It is also important to interpret what is seen, such as whether side-to-side asymmetry is likely due to uniform collapse or something else such as old dissections or anatomical variance. An example of the interpretive approach using the illustrated case in the new article [1] is that there is a clearly visible side-to-side difference with uniform collapse where the distal artery otherwise seems normal (A + C), small absolute ICA size (B and provided measurement), ICA similar to ECA (A + C), and stenosis hard to assess due to calcifications. The interpretation of these findings is a nearocclusion without full collapse, and the interpretation seems certain from available information (even though the stenosis could not be clearly assessed, but it could be impressive). The interpretative approach is justified as it was used for the pooled NASCET and ECST analyses [5], from which we base our understanding of prognosis and management. While the definition of near-occlusion with interpretation might still...

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Carotid Near-Occlusion: A Comprehensive Review, Part 2—Prognosis and Treatment, Pathophysiology, Confusions, and Areas for Improvement

Cited by 36 publications

References 51 publications

Carotid endarterectomy in patients with recurrent symptoms associated with an ipsilateral carotid artery near occlusion with full collapse

Carotid endarterectomy in patients with recurrent symptoms associated with an ipsilateral carotid artery near occlusion with full collapse

Carotid near-occlusion is often overlooked when CT angiography is assessed in routine practice

Diagnosing carotid near-occlusion with 1 mm side-to-side asymmetry: a tough task made too easy

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