Defining carotid near-occlusion with full collapse: a pooled analysis

Abstract

Purpose Create a new definition of near-occlusion with full collapse to predicting recurrent stroke. Methods Pooled analysis of two studies. Patients with symptomatic ≥ 50% carotid stenoses were included. Outcome was preoperative recurrent ipsilateral ischemic stroke or retinal artery occlusion within 28 days of presenting event. We analyzed several artery diameters on computed tomography angiography and stenosis velocity on ultrasound. Results A total of 430 patients with symptomatic ≥ 50% carotid stenosis were included, 27% had near-occlusion. By traditional definition, 27% with full collapse and 11% without full collapse reached the outcome (p = 0.047). Distal internal carotid artery (ICA) diameter, ICA ratio, and ICA-to-external carotid artery ratio were associated with the outcome. Best new definition of full collapse was distal ICA diameter ≤ 2.0 mm and/or ICA ratio ≤ 0.42. With this new definition, 36% with full collapse and 4% without full collapse reached the outcome (p < 0.001). Conclusions Defining near-occlusion with full collapse as distal ICA diameter ≤ 2.0 mm and/or ICA ratio ≤ 0.42 seems to yield better prognostic discrimination than the traditional appearance-based definition. This novel definition can be used in prognostic and treatment studies of near-occlusion with full collapse.

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

“…Calipers were systematically placed in the middle of the “fuzzy edge,” without extra magnification. Full collapse was defined as distal ICA diameter ≤ 2.0 mm and/or ICA ratio ≤ 0.42 [ 2 ].…”

“…Near-occlusions can be subdivided into a less severe subset (without full collapse) and a more severe subset (with full collapse) [ 1 ]. A prognosis-based definition of full collapse (distal ICA diameter ≤ 2.0 mm and/or ICA ratio ≤ 0.42) has been proposed, resulting in a high risk of early stroke recurrence (31% within 14 days of presenting event) for full collapse and low risk (4%) for without full collapse [ 2 ]. We have found no study that compared angiographic appearances of symptomatic and asymptomatic near-occlusions.…”

The periprocedural and 30-day outcomes of carotid stenting in patients with carotid artery near-occlusion

“…Patients with post-stenotic distal ICA narrowing due to anatomic variants such as ICA asymmetry associated with circle of Willis variations were excluded from this study 18 . CANO with full collapse was defined as a distal ICA lumen diameter ≤ 2 mm and/or ipsilateral ICA/contralateral ICA diameter ratio ≤ 0.42 2 . The angiograms were retrospectively reviewed by 2 independent investigators experience in cerebral angiography, who were blinded to the procedural and clinical information.…”

“…There are 2 subtypes of CANO, severe form with full collapse (thread like distal ICA lumen) versus partial form without full collapse (a normal-appearing but narrowed distal ICA lumen) (Fig. 1 ), and their prognosis could be different 2 . Current guideline suggests medical treatment for CANO 3 , but the recommendations are based on experts’ consensus on an assumed low stroke risk and high revascularization complication rates.…”

Diagnosing carotid near-occlusion is a difficult task—but it might get easier

“…Whether near-occlusion with full collapse (Fig. 2) should be identified and treated separately from without full collapse is debatable [6][7][8]. In this editorial, we will put these findings in a larger perspective, highlighting difficulties in image assessments and diameter measurements, and present a possible solution for future studies: postoperative angiography as a new reference test.…”