Initial experience of using the filter protection device during carotid artery stenting in Japan

Real-world Experience of Carotid Artery Stenting in Japan: Analysis of 8458 Cases from the JR-NET3 Nationwide Retrospective Multi-center Registries

We aimed to clarify the outcomes of carotid artery stenting (CAS) in the Japanese population. For this purpose, we reviewed data from the Japanese Registry of NeuroEndovascular Therapy 3 (JR-NET3), a retrospective, nation-wide, multi-center, observational study of neuroendovascular treatments in Japan. Of the 9207 patients who underwent CAS between January 2010 and December 2014, 8458 satisfied the inclusion criteria for our analysis. The outcome statistics of this JR-NET3 cohort were compared to those of JR-NET1 and 2 cohorts fitting the same inclusion criteria. Of the 8458 JR-NET3 patients analyzed, 8042 (95.1%) were treated by surgeons with board certification from the Japanese Society for NeuroEndovascular Therapy. Technical success was achieved in 8417 patients (99.5%), whereas 198 patients (2.3%) had clinically significant complications (CSCs). These findings mirrored those obtained for the JR-NET1 and 2 cohorts. On multivariate analysis, risk factors for CAS-associated CSC included symptomatic lesion [odds ratio (OR), 1.91; 95% confidence interval (CI), 1.23-3.00; P = 0.003] and hypoechoic lesion on carotid artery ultrasound (OR, 1.85; 95% CI, 1.21-2.84; P = 0.005), whereas use of closed-cell stents was a predictor of better outcome (OR, 0.53; 95% CI, 0.35-0.79; P = 0.002). The findings of JR-NET3 reflect good outcomes of CAS, but non-modifiable risk factors reflecting lesion characteristics remain of concern. Using closed-cell stents is advisable. Technological advances such as the introduction of new materials may help further improve CAS outcomes in Japanese patients.

Silent brain infarcts on diffusion-weighted imaging after carotid revascularisation: A surrogate outcome measure for procedural stroke? A systematic review and meta-analysis

Aim

To investigate whether lesions on diffusion-weighted imaging (DWI+) after carotid artery stenting (CAS) or endarterectomy (CEA) might provide a surrogate outcome measure for procedural stroke.

Materials and Methods

Systematic MedLine® database search with selection of all studies published up to the end of 2016 in which DWI scans were obtained before and within seven days after CAS or CEA. The correlation between the underlying log odds of stroke and of DWI+ across all treatment groups (i.e. CAS or CEA groups) from included studies was estimated using a bivariate random effects logistic regression model. Relative risks of DWI+ and stroke in studies comparing CAS vs. CEA were estimated using fixed-effect Mantel-Haenszel models.

Results

We included data of 4871 CAS and 2099 CEA procedures (85 studies). Across all treatment groups (CAS and CEA), the log odds for DWI+ was significantly associated with the log odds for clinically manifest stroke (correlation coefficient 0.61 (95% CI 0.27 to 0.87), p = 0.0012). Across all carotid artery stenting groups, the correlation coefficient was 0.19 (p = 0.074). There were too few CEA groups to reliably estimate a correlation coefficient in this subset alone. In 19 studies comparing CAS vs. CEA, the relative risks (95% confidence intervals) of DWI+ and stroke were 3.83 (3.17-4.63, p < 0.00001) and 2.38 (1.44-3.94, p = 0.0007), respectively.

Discussion

This systematic meta-analysis demonstrates a correlation between the occurrence of silent brain infarcts on diffusion-weighted imaging and the risk of clinically manifest stroke in carotid revascularisation procedures.

Conclusion

Our findings strengthen the evidence base for the use of DWI as a surrogate outcome measure for procedural stroke in carotid revascularisation procedures. Further randomised studies comparing treatment effects on DWI lesions and clinical stroke are needed to fully establish surrogacy.

Effect of cilostazol in preventing restenosis after carotid artery stenting using the carotid wallstent: a multicenter retrospective study

BACKGROUND AND PURPOSE

Restenosis after CAS is a postoperative problem, with a reported frequency of approximately 2%-8%. However differences in stent design, procedure, and the antiplatelet agent appear to affect the incidence of restenosis. We assessed the frequency of restenosis and the effect of the antiplatelet agent CLZ in preventing restenosis after CAS by the standard procedure using the CWS.

MATERIALS AND METHODS

Between May 2010 and October 2011, 62 lesions in 60 consecutive patients underwent CAS using the CWS at 4 medical institutions, and all patients were followed clinically and assessed by sonography, 3D-CTA, or angiography at 3 and 6 months postoperatively. Restenosis was defined as ≥50% stenosis. The incidence of restenosis and the variation in the incidence of restenosis by the difference in type of antiplatelet agent between the CLZ group (n = 30; aspirin, 100 mg, and CLZ, 200 mg) and the non-CLZ group (n = 32; aspirin, 100 mg, and clopidogrel, 75 mg [n = 29]; or ticlopidine, 100 mg [n = 2] or 200 mg [n = 1]) were retrospectively investigated. Two antiplatelet agents were given starting 1 week preoperatively until at least 3 months postoperatively.

RESULTS

Restenosis occurred in 5 patients (8.3%), but all were cases of asymptomatic lesions in the follow-up period. All 5 patients with restenosis were in the non-CLZ group, with no cases of restenosis in the CLZ group; the difference was significant (P = .0239).

CONCLUSIONS

The restenosis rate after CAS by using the CWS was 8.3%. CLZ was associated with significant inhibition of restenosis.

Significance of blood aspiration in carotid artery stenting with Angioguard XP

BACKGROUND AND PURPOSE

In some patients, angiographic flow impairment is observed during carotid artery stenting (CAS) using Angioguard XP (AGXP), resulting in neurological symptoms. CAS was thus modified to improve clinical outcome.

METHODS

Ninety-seven patients were treated with CAS using AGXP from January 2008 to October 2009. In period I (January-December 2008; n = 53), blood aspirations were performed only in no-flow cases. In period II (January-October 2009; n = 44), blood aspirations were performed in no-flow and slow-flow cases. Clinical outcome, detection of microembolic lesions on diffusion-weighted imaging (DWI) and flow impairment during CAS were examined between these two periods before and after modifying the CAS procedure.

RESULTS

Periprocedural transient ischemic attacks occurred in 10 patients (18.9%) and one patient (2.27%) in periods I and II, respectively (P = .018). Minor and major strokes were observed in two patients in each period (P = .849). New ipsilateral DWI lesions were detected in 25 patients (47.2%) and 11 patients (25.0%) in periods I and II, respectively (P = .024). Among 18 slow-flow cases, new DWI lesions were detected in one patient (9.09%) and five patients (71.4%) with (n = 11) and without (n = 7) blood aspirations, respectively (P = .013). Neurological symptoms were observed only in three of seven patients (42.9%) without aspirations, compared to one of 11 patients (9.1%) with aspirations (P = .043).

CONCLUSION

Postoperative symptomatic stroke and new DWI lesions are significantly associated with blood flow impairment during CAS using AGXP. When flow impairment occurs, blood aspiration should be performed.

Assessment of necrotic core with intraplaque hemorrhage in atherosclerotic carotid artery plaque by MR imaging with 3D gradient-echo sequence in patients with high-grade stenosis

Object

The aim of this study was to assess the histopathological differences between advanced atherosclerotic carotid artery (CA) plaques with signal hyperintensity on T1-weighted MR images and those without, focusing on necrotic core size and intraplaque hemorrhage (IPH).

Methods

Thirty-five patients scheduled for carotid endarterectomy underwent preoperative CA MR imaging using 3D inversion-recovery-based T1-weighted imaging (magnetization-prepared rapid acquisition gradient-echo [MPRAGE]). The signal intensity of the CA plaque on MPRAGE sequences was classified as “high” when the intensity was more than 200% that of adjacent muscle. A total of 96 axial MR images obtained in 35 patients were compared with corresponding histological sections from 36 excised specimens. The area of the necrotic core in histological sections was compared between specimens with and without high signal intensity on MPRAGE sequences. The IPH was histopathologically graded according to the size of the area positive for glycophorin A as revealed by immunohistochemical staining. The difference between plaques with and without high signal intensity was investigated with respect to the degree of IPH. The relationship of the severity of IPH to size of the necrotic core was also evaluated.

Results

The area of the necrotic core in plaques with high signal intensity on MPRAGE sequences was significantly larger than that in plaques without high signal intensity (median 51.2% [interquartile range 43.3–66.8%] vs 49.0% [33.2–57.6%], p = 0.029). Carotid artery plaques with high signal intensity had significantly more severe IPH than plaques with lower signal intensity (p < 0.0001). The severity of IPH was significantly associated with the size of the necrotic core (p < 0.0001).

Conclusions

Atherosclerotic CA plaques with high signal intensity on MPRAGE sequences had large necrotic cores with IPH in patients with high-grade stenosis; MPRAGE is useful for the evaluation of CA plaque progression.

Simple immersion of filter devices into an urokinase solution prevents fibrin net formation during carotid artery stenting

Slow-flow phenomenon is frequently observed during carotid artery stenting (CAS) with a filter embolic protection device. It results in technical difficulties and can lead to adverse neurological events. Flow impairment is thought to be caused by plaque entrapped by the filter and/or blood coagulation on the filter. Characteristics of heparin- or urokinase-treated polyurethanes were analyzed by surface plasmon resonance, and the fibrinolytic activity of the urokinase-treated filter of Angioguard XP was estimated by the fibrin plate assay. A filter membrane of Angioguard XP protection device was treated with a heparin or urokinase solution. In clinical studies, six and nine patients were treated by CAS using Angioguard XP modified with heparin and urokinase, respectively. Filter membranes were examined by scanning electron microscopy (SEM). From in vitro studies, it appeared that urokinase adsorbed and remained on the Angioguard XP filter, and its fibrinolytic activity was demonstrated even after washing with saline; heparin, however, was easily washed out from the surface. From clinical study, some filter pores were obstructed in all six patients in the heparin group and in three patients in the urokinase group. Fibrin net was found on the filter in five of six patients in the heparin group and in one of nine patients in the urokinase group. Treatment of an Angioguard XP filter with a urokinase solution is effective in preventing pore occlusion and may reduce occurrence of the slow-flow phenomenon.

Magnetic resonance plaque imaging to predict the occurrence of the slow-flow phenomenon in carotid artery stenting procedures

INTRODUCTION

The purpose is to investigate the feasibility of magnetic resonance (MR) plaque imaging in predicting the arterial flow impairment (slow-flow phenomenon) during carotid artery stenting (CAS) using a filter-type protection device.

METHODS

Thirty-one carotid artery stenotic lesions in 30 patients (28 men and two women; mean age, 71.8 years) were evaluated by MR plaque imaging with black blood T1- and T2-weighted and time-of-flight sequences before CAS. Main plaque components were classified as vulnerable (intraplaque hemorrhage and lipid-rich/necrotic core) or stable (fibrous tissue and dense calcification) from the signal pattern. The plaque classification was statistically compared with the occurrence of slow-flow phenomenon.

RESULTS

The slow-flow phenomenon was observed in ten CAS procedures (five flow arrests and five flow reductions). Flow arrests consisted of four vulnerable and one stable plaque, and flow reductions consisted of four vulnerable and one stable plaque. The slow-flow phenomenon occurred significantly (P<0.01) more frequently in patients with vulnerable plaque.

CONCLUSIONS

Vulnerable carotid plaques have a significantly higher risk of slow-flow phenomenon than stable plaques. The occurrence of the slow-flow phenomenon can be predicted by MR plaque imaging before CAS.