Carotid artery stenting for vulnerable plaques on MR angiography and ultrasonography: utility of dual protection and blood aspiration method

Outcome of CAS under flow reversal and analysis for the intraprocedural flow of internal carotid artery

OBJECTIVE

Carotid artery stenting (CAS) under flow reversal with dual protection using a proximal balloon and distal filter has been an established procedure for internal carotid artery (ICA) stenosis. This study investigates the effect of external carotid artery (ECA) occlusion on outcomes of CAS and ICA flow under flow reversal.

METHODS

We reviewed 231 cases of CAS under flow reversal with ECA occlusion and 32 without. In the last 14 of 32 cases, the flow in the ICA under flow reversal was analyzed by ultrasound. The collateral index, which was defined as the total value of the maximum diameters of the ipsilateral anterior cerebral artery at the A1 segment and the anterior communicating artery, as well as those of the ipsilateral posterior cerebral artery at the P1 segment and the ipsilateral posterior communicating artery, and the maximum diameter of the ipsilateral ECA were correlated with the flow direction in the ICA.

RESULTS

There was no significant difference in the outcome of CAS between the groups with or without ECA occlusion. Among the 14 cases without ECA occlusion, antegrade flow in the ICA was observed in 6 cases (42.9 %). The group with the antegrade flow in the ICA exhibited a significantly lower collateral index (5.08±0.33 vs 6.71±0.28, p=0.01) and a significantly larger ECA diameter (4.66±0.51 mm vs 3.21±1.24 mm, p=0.01) than the group with the stagnant or retrograde flow in the ICA.

CONCLUSIONS

The outcomes of CAS under flow reversal were acceptable even without ECA occlusion. The ECA occlusion may not be necessary for CAS under dual protection; however, distal filter protection should be used even under flow reversal.

Strategy of carotid artery stenting as first-line treatment and carotid endarterectomy for carotid artery stenosis: A single-center experience

Background:

The main surgical options for stenosis of the carotid artery are carotid endarterectomy (CEA) and carotid artery stenting (CAS). The number of CAS procedures performed in Japan greatly exceeds that of CEA procedures. In this study, we used data from a single center to examine CAS and CEA for carotid artery stenosis.

Methods:

The subjects were patients with carotid artery stenosis who underwent CAS or CEA between January 2012 and May 2020. CAS was the first-choice treatment. CEA was used in cases with vulnerable plaques, a relatively low risk of general anesthesia, and no anatomical features disadvantageous for endarterectomy.

Results:

A total of 140 cases (102 CAS and 38 CEA) were examined. There were more elderly patients in the CAS group. The CEA group had a higher rate of vulnerable plaques and only one case with an unfavorable anatomy for CEA. Major adverse events (stroke) occurred in two CAS cases. In multivariate logistic analysis, postoperative ischemic lesions were independently associated with age (odds ratio [OR] = 1.13, 95% confidence interval [CI]: 1.01–1.26, P = 0.026) and vulnerable plaque (OR = 5.54, 95% CI: 1.48–20.70, P = 0.011) in the CAS group, but not in the CEA group.

Conclusion:

The results reflect the treatment algorithm at our hospital, indicating that triage is accurate. Thus, it is beneficial to assign cases based primarily on plaque vulnerability and anatomical risk for CEA, and to not hesitate to perform CEA simply because of old age. CAS as first-line treatment and CEA are effective and safe, which reflect the treatment situation in Japan.

Thin calcification (< 2 mm) can highly predict intraplaque hemorrhage in carotid plaque: the clinical significance of calcification types

PURPOSE

Calcification pathogenesis and the relationship between calcification and plaque composition remain unclear. This study explored the calcification characteristics of vulnerable plaques, especially focusing on calcification thickness, using computed tomography angiography and magnetic resonance plaque imaging.

METHODS

Demographic, computed tomography angiography, and magnetic resonance plaque imaging data were acquired from 178 patients with 229 lesions diagnosed with carotid stenosis. The calcification types were categorized by calcification thickness. We evaluated their features, including the anatomical location and the plaque composition compared with MR plaque imaging, and clarify the clinical characteristics. Furthermore, an immunohistochemical subgroup analysis was performed on 84 lesions treated with carotid endarterectomy.

RESULTS

The result of the ROC analysis suggested the threshold between symptomatic and asymptomatic calcification was 2.04 mm (AUC;0.841, 95%CI; 0.771-0.894). Calcification with ≥ 2 mm thickness was classified as thick calcification and < 2 mm thickness as thin calcification. Multivariate analysis suggested the prevalence of symptomatic patients in the thin calcification group was significantly higher than others (P = 0.01; odds ratio, 4.1; 95% confidence interval 2.8-7.2). Plaques with thin calcification were associated with plaque with intraplaque hemorrhage (P < 0.01). The interobserver reliability (κ) of calcification type was 0.962 (95% confidence interval, 0.941-0.988). Immunohistochemical analysis demonstrated that the numbers of CD68-positive cells and CD31-positive microvessels in shoulder lesions were significantly higher in the thin calcification group than in the non-thin group (both P < 0.01).

CONCLUSIONS

Thin calcification was associated with plaques with intraplaque hemorrhage and had different clinical implications than thick calcification.

Carotid Artery Stenting in Patients With Contralateral Carotid Occlusion Using a Combined Protection Method

BACKGROUND AND PURPOSE

Carotid artery stenting has become widespread as a revascularization method and has increasingly replaced carotid endarterectomy for treating internal carotid artery stenosis with contralateral carotid occlusion. Hence, this study aimed to establish the clinical characteristics and perioperative outcomes of carotid artery stenting for internal carotid artery stenosis in patients with contralateral carotid occlusion using a combined protection method.

METHODS

This retrospective single-center study assessed 218 patients with internal carotid artery stenosis who underwent carotid artery stenting using the dual protection (simultaneous flow reversal and distal filter) and blood aspiration method. We distinguished 2 patient groups: contralateral carotid occlusion (n = 11) and no contralateral carotid occlusion (n = 207). We evaluated the patients' characteristics, intraoperative transient neurological symptoms, hypotension, bradycardia, major adverse events (major stroke, myocardial infarction, and death within 90 days), minor stroke, hyperintensities on diffusion-weighted images after carotid artery stenting, captured visible debris, and restenosis.

RESULTS

In this cohort, 5% of patients with internal carotid artery stenosis had contralateral carotid occlusion. No statistically significant differences in patient characteristics existed between the groups. The success rate of carotid artery stenting was 100%. There were no statistically significant differences in intraoperative complications, postoperative major adverse events, or other outcomes between both groups.

CONCLUSIONS

In this cohort, carotid artery stenting using dual protection combined with blood aspiration was safe and effective in preventing distal embolism in patients with internal carotid artery stenosis and contralateral carotid occlusion.

Computed Tomography Texture Analysis of Carotid Plaque as Predictor of Unfavorable Outcome after Carotid Artery Stenting: A Preliminary Study

Novel biomarkers are advocated to manage carotid plaques. Therefore, we aimed to test the association between textural features of carotid plaque at computed tomography angiography (CTA) and unfavorable outcome after carotid artery stenting (CAS). Between January 2010 and January 2021, were selected 172 patients (median age, 77 years; 112/172, 65% men) who underwent CAS with CTA of the supra-aortic vessels performed within prior 6 months. Standard descriptors of the density histogram were derived by open-source software automated analysis obtained by CTA plaque segmentation. Multiple logistic regression analysis, receiver operating characteristic (ROC) curve analysis and the area under the ROC (AUC) were used to identify potential prognostic variables and to assess the model performance for predicting unfavorable outcome (periprocedural death or myocardial infarction and any ipsilateral acute neurological event). Unfavorable outcome occurred in 17/172 (10%) patients (median age, 79 years; 12/17, 70% men). Kurtosis was an independent predictor of unfavorable outcome (odds ratio, 0.79; confidence interval, 0.65-0.97; p = 0.029). The predictive model for unfavorable outcome including CTA textural features outperformed the model without textural features (AUC 0.789 vs. 0.695, p = 0.004). In patients with stenotic carotid plaque, kurtosis derived by CTA density histogram analysis is an independent predictor of unfavorable outcome after CAS.

Safety of simultaneous bilateral carotid artery stenting for bilateral carotid artery stenosis

BACKGROUND

Bilateral carotid artery stenting (BCAS) is often performed in two stages (staged BCAS) but it is also an option to be performed in one stage (simultaneous BCAS). To confirm the safety of simultaneous BCAS, we retrospectively analyzed perioperative and postoperative course of simultaneous BCAS compared with staged BCAS.

MATERIALS AND METHODS

Patients with symptomatic stenosis of ≥50% or asymptomatic stenosis of ≥80% of bilateral carotid arteries underwent BCAS. Procedure time, symptomatic ischemic complications, presence/absence of high-intensity spots on postoperative diffusion-weighted image, duration of postoperative hospital stays and 30 days outcome of patients performed with simultaneous BCAS (group A, 8 patients with 16 stenotic lesions (8 procedures)) were compared with those of staged BCAS (group B, 4 patients with 8 stenotic lesions (8 procedures)).

RESULTS

In groups A and B, procedure time was 146.0 ± 53.8 and 103.5 ± 39.4 min; intraoperative hypotension was observed in 62.5% and 50.0%; postoperative hypotension occurred in 37.5% and 50.0%; diffusion-weighted image showed high-intensity spots in 37.5% and 12.5%; and duration of postoperative hospital stays was 5.1 ± 1.8 and 5.3 ± 2.3 days. No patients suffered symptomatic ischemic complications. In simultaneous BCAS, there was a tendency that procedure time was longer and high-intensity spots on postoperative diffusion-weighted image was more frequent, but there was no increase in symptomatic ischemic complications and duration of hospital stays compared to staged BCAS.

CONCLUSIONS

Safety of simultaneous BCAS may not be inferior to staged BCAS. In terms of duration of hospital stays, simultaneous BCAS can be superior to staged BCAS for patients with bilateral carotid artery stenosis.

Safety of carotid artery stenting for elderly patients with cervical carotid artery stenosis

BACKGROUND

Several recent randomized controlled trials have reported that perioperative complications of carotid artery stenting increase with age, and Japan has the highest proportion of elderly in the world. We retrospectively compared clinical factors, treatment outcomes, and adverse events between younger and elderly carotid artery stenting patients at a single institution in Japan to assess carotid artery stenting safety for the aged population.

METHODS

A total of 150 consecutive patients treated with carotid artery stenting using the dual protection (simultaneous flow reversal and distal filter) and blood aspiration method were enrolled. Patients were classified into an elderly (O) group ≥75 years (54/150, 36.0%) and a younger (Y) group <75 years (96/150, 64%) for comparison of demographics, clinical background, incidence of captured debris during the procedure, outcome, minor stroke, major adverse events (major stroke, myocardial infarction, or death) within 30 days, hyperintense spots on diffusion-weighted images after carotid artery stenting, and postoperative hospitalization days.

RESULTS

The carotid artery stenting procedure was successful in all cases. No major adverse events occurred within 30 days in the Y group, and only one occurred in the O group (P = 0.348). Visible debris was captured in a significantly greater proportion of O group patients than in Y group patients (33/54 (63.5%) vs. 40/96 (42.1%), P = 0.016), but there was no significant difference in the frequency of hyperintense spots on diffusion-weighted images between Y and O groups (23/96 (24.0%) vs. 16/52 (30.8%), P = 0.435).

CONCLUSIONS

Carotid artery stenting using dual protection and blood aspiration is equally safe for younger and elderly patients.

Editorial comment: sandwich carotid stenting: too much of a good thing?

This editorial comment refers to the article "Detection of in-stent protrusion (ISP) by intravascular ultrasound during carotid stenting: usefulness of stent-in-stent placement for ISP" by Okazaki T et al Eur Radiol., July 2018.

Reversible cerebral vasoconstriction complicated with brain infarction immediately after carotid artery stenting

Reversible cerebral vasoconstriction is a very rare complication after carotid artery stenting (CAS). It has been reported to occur more than several hours after CAS and to have a good clinical course. A 73-year-old man underwent CAS for a high-grade symptomatic stenosis of his left carotid artery. Immediately after CAS, he had consciousness disturbance and right hemiparesis. We first suspected hyperperfusion syndrome, but antihypertensive therapy exacerbated his symptoms. On repeated postoperative angiography, the middle cerebral artery (MCA) appeared to become progressively narrower. Perfusion computed tomography indicated hypoperfusion in the left MCA territory, so we diagnosed the patient with ischemic symptoms due to hypoperfusion associated with MCA vasoconstriction. Although these findings were temporary, right weakness and cognitive dysfunction lingered and caused severe disability. As vasoconstriction after CAS may result in a poor outcome, it must be promptly distinguished and treated accordingly.

Retinal artery occlusion during carotid artery stenting with distal embolic protection device

Retinal artery occlusion associated with carotid artery stenosis is well known. Although it can also occur at the time of carotid artery stenting, retinal artery occlusion via the collateral circulation of the external carotid artery is rare. We encountered two cases of retinal artery occlusion that were thought to be caused by an embolus from the external carotid artery during carotid artery stenting with a distal embolic protection device for the internal carotid artery. A 71-year-old man presented with central retinal artery occlusion after carotid artery stenting using the Carotid Guardwire PS and a 77-year-old man presented with branch retinal artery occlusion after carotid artery stenting using the FilterWire EZ. Because additional new cerebral ischaemic lesions were not detected in either case by postoperative diffusion-weighted magnetic resonance imaging, it was highly likely that the debris that caused retinal artery occlusion passed through not the internal carotid artery but collaterals to retinal arteries from the external carotid artery, which was not protected by a distal embolic protection device. It is suggested that a distal protection device for the internal carotid artery alone cannot prevent retinal artery embolisation during carotid artery stenting and protection of the external carotid artery is important to avoid retinal artery occlusion.

The Safety of Carotid Artery Stenting for Patients in the Acute Poststroke Phase

BACKGROUND

The efficacy of carotid artery stenting (CAS) for patients in the acute poststroke phase has not been established. We investigated the outcome of CAS for patients with symptomatic internal carotid artery (ICA) stenosis in the acute poststroke phase.

METHODS

We performed a retrospective analysis of all patients who underwent CAS for symptomatic ICA stenosis in our institution. Patients in whom the time interval between neurological deterioration and the CAS procedure was less than 3 days were included in the early group, and the other patients were included in the delayed group. Perioperative complications including major adverse events (MAEs) were compared between the early and the delayed groups.

RESULTS

One hundred five patients were included in the study. Forty patients were assigned to the early group and 65 patients were assigned to the delayed group. The overall MAE rate was 4.8%. There was no significant increase in the perioperative MAE in the early group compared with the delayed group (early group 2.5% versus delayed group 6.5%, P = .65). In the early group, 25 of 40 patients (62.5%) were functionally independent (modified Rankin scale [mRS] score of 0-2) at discharge. Significant differences between the independent patients and the disabled patients (mRS score of 3-6) included age (independent 72 versus disabled 79, P < .01) and prevalence of transient ischemic attack (36.0% versus .0%, P = .02).

CONCLUSIONS

CAS performed within 3 days from the last ischemic event did not increase the risk of perioperative complication. Early CAS may be a useful option for the treatment of symptomatic carotid artery stenosis.