Current update of cerebral embolic protection devices

Embolic protection devices for carotid artery stenting: A network meta-analysis

OBJECTIVES

Carotid artery stenting (CAS) is an alternative treatment option for patients at high risk for carotid endarterectomy (CEA) but has been correlated with increased risk for distal embolization and periprocedural stroke despite the use of adjunctive embolic protection devices (EPD). This study compared four types of EPDs and their intra and periprocedural related complications.

METHODS

A systematic review of the literature was conducted in PubMed/Medline to identify studies that investigated the outcomes of CAS with adjuvant use of EPDs, including Proximal Balloon (PB), Distal Filter (DF), and Distal Balloon (DB) strategy. Continuous flow reversal performed via transcarotid approach by a commercially available device as an embolic protection strategy was intentionally excluded based on its distinct procedural characteristics and lack of availability outside of the United States. This network meta-analysis was performed according to the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines.

RESULTS

Overall, 45 studies, consisting of 7600 participants satisfied the predetermined search criteria and were included in this network meta-analysis. Overall, 13 studies provided data regarding the number of patients with new ischemic lesions detected in the DW-MRI. DF (OR: 3.15; 95% CI: 1.54-6.44; p = 0.002) and DB (OR: 2.28; 95% CI: 1.58-3.29; p < 0.001) were associated with higher odds of new ischemic lesions compared to PB on DW-MRI imaging. No statistical difference was identified between DB versus DF groups (OR: 1.48; 95% CI: 0.73-2.59; p = 0.317). 36 and 27 studies reported on periprocedural stroke and transient ischemic attack (TIA) rates, respectively, showing similar odds of neurologic adverse events between all three groups.

CONCLUSIONS

PB deployment during CAS is superior to DF and DB in preventing distal embolization phenomena. However, no statistically significant difference in TIA and stroke rate was found among any of the analyzed EPD groups. Further research is warranted to investigate the association of embolic phenomena on imaging after CAS with clinically significant neurologic deficits.

In Silico Hemodynamics and Filtering Evaluation of a Commercial Embolic Protection Device

During the last years, several kinds of Embolic Protection Devices (EPD) have been developed, with the aim of minimizing complication caused by thrombi generated during Carotid Artery Stenting (CAS). These devices are capable of capturing small particles generated during the intervention, avoiding cerebral stroke and improving the outcomes of the surgery. However, they have associated complications, like the increase on flow resistance associated by their use or the lack of knowledge on their actual filtration efficiency for thrombi of low size. Current work proposes a validated computational methodology in order to predict the hemodynamic features and filtering efficiency of a commercial EPD. It will be observed how Computational Fluid Dynamics predicts pressure drop with fair agreement with the experimental measurements. Finally, this work analyzes the filtration efficiency and the influence of the distribution of injected particles on this parameter. The capabilities of the filter for retaining particles of diameter below the pore size is, additionally, discussed.

Ostial common carotid artery occlusion and balloon-mounted stenting: Implication of embolic protection device in tandem lesion

Ostial common carotid artery (CCA) stenosis is rare, compared to extracranial internal carotid artery bifurcation lesions. In cases of a tandem lesion, the proximal lesion usually involves the extracranial internal carotid artery, and the ostial CCA is rarely implicated. A 69-year-old woman who underwent 3 months of antiplatelet therapy for asymptomatic, right ostial, severely calcified CCA stenosis presented with sudden onset left hemiparesis. Radiographic examination revealed an ostial CCA-intracranial artery tandem lesion. After intracranial revascularization using a clot retrieval stent, we performed the endovascular treatment with a balloon-mounted stent using an embolic protection device. This procedure may be superior to others because it is possible to achieve early intracranial revascularization and prevent distal embolism during the complete treatment of proximal lesions.

Iatrogenic ophthalmic artery occlusion and retinal artery occlusion

Iatrogenic ophthalmic artery occlusion (IOAO) is a rare but devastating ophthalmic disease that may cause sudden and permanent visual loss. Understanding the possible etiologic modalities and pathogenic mechanisms of IOAO may prevent its occurrence. There are numerous medical etiologies of IOAO, including cosmetic facial filler injection, intravascular procedures, intravitreal gas or drug injection, retrobulbar anesthesia, intraarterial chemotherapy in retinoblastoma. Non-ocular surgeries and vascular events in arteries that are not directly associated with the ophthalmic artery, can also cause IOAO. Since IOAO has a limited number of treatment modalities, which lead to poor final visual prognosis, it is imperative to acknowledge the information regarding medical procedures that are etiologically associated with IOAO. We accumulated all searchable and available IOAO case reports (our cases and previous reported cases from the literature), classified them according to their mechanisms of pathogenesis, and summarized treatment options and responses of each of the causes. Various sporadic cases of IOAO can be categorized into three mechanisms as follows: intravascular event, orbital compartment syndrome, and increased intraocular pressure. Embolic IOAO, which is considered the primary cause of the condition, was classified into three subgroups according to the pathway of embolic movement (retrograde pathway, anterograde pathway, pathway through collateral channels). Despite the practical limitations of treating spontaneous (non-iatrogenic) retinal artery occlusion, this article will contribute in predicting and improving the prognosis of IOAO by recognizing the treatable factors. Furthermore, it is expected to provide clues to future research associated with the treatment of retinal artery occlusion.

Massive Cerebral Microemboli after Protected Carotid Artery Angioplasty and Stenting Using a Distal Filter Embolic Protection Device for a Vulnerable Plaque with a Lipid Rich Necrotic Core and Intraplaque Hemorrhage: A Case Report

A major concern associated with carotid artery angioplasty and stenting (CAS) is a periprocedural distal cerebral embolization. To prevent distal embolization, embolic protection devices (EPDs) have been developed. However, the risk of cerebral embolism after protected CAS in patents with a vulnerable plaque is controversial and either a silent or a symptomatic stroke can occur despite the use of EPDs. Here, we report a case of a massive cerebral microemboli after a protected CAS using a distal filter EPD for a vulnerable plaque with a lipid rich necrotic core and intraplaque hemorrhage.

Acute Ischemic Stroke due to Common Carotid Ostial Disease with Tandem Intracranial Occlusions Treated with Thrombectomy and Staged Retrograde Stenting

Background

Acute ischemic stroke due to tandem occlusive lesions of the anterior circulation involves an intracranial large vessel occlusion as well as a concurrent occlusion or high-grade stenosis of the proximal carotid system. The vast majority of proximal lesions in tandem occlusive cases involve the extracranial internal carotid artery, although the lesion can theoretically exist anywhere along the carotid artery pathway, including the common carotid ostium.

Summary

To the best of our knowledge, only 1 report describes common carotid artery ostial lesions in the setting of acute ischemic stroke due to tandem occlusions, in which the authors describe an anterograde treatment paradigm. We present the first 2 cases of acute ischemic stroke secondary to common carotid ostial disease with tandem intracranial occlusion, treated with intracranial thrombectomy followed by subsequent staged balloon-mounted stenting of the common carotid ostium. We review the pathophysiology of tandem occlusions, the controversy surrounding treatment techniques, and various approaches used in the treatment of ostial occlusive lesions.

Key Message

In certain situations where acute carotid stenting is not safe or technically possible, immediate intracranial thrombectomy with a subsequent staged balloon-mounted stenting of the ostial lesion may be a reasonable and safe option.

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.

Cerebral embolic protection during endovascular arch replacement

Despite excellent results in high volume centers, open repair of aortic arch pathology is highly invasive, and can result in significant morbidity and mortality in high risk patients. Near-total and hybrid approaches to aortic arch disease states have emerged as an alternative for patients deemed moderate to high risk for conventional repair. Advantages of these approaches include avoidance of extracorporeal circulation and hypothermic circulatory arrest as well as avoidance of cross clamping, all of which are not well tolerated in high risk patients. Anatomically high-risk patients with anastomotic aneurysms from previous arch reconstruction may also benefit from these less invasive approaches. Medical devices designed specifically for the aortic arch are developing at a rapid pace and continue to evolve. Dedicated devices for zone 0-2 aortic arch repair are currently available under special access or being studied in clinical trials. Unfortunately, stroke continues to be the Achilles heel of endovascular approaches to the aortic arch, with cerebral embolism being the culprit in the majority of such cases. This perspective article describes the epidemiology, procedures, and mitigation strategies for current near-total and hybrid approaches to aortic arch pathology, and specifically addresses current means of embolic protection and future direction.

Transcarotid artery stenting for carotid artery pseudoaneurysm using flow reversal technique

Carotid artery pseudoaneurysm results mostly from direct trauma, prior endarterectomy, prior dissection, radiation, and infections. There are many different surgical and endovascular treatment options for repair, and the choice of treatment depends on patient-, surgeon-, and institute-related factors. Studies have reported the efficacy of various endovascular techniques for aneurysm repair, including stent graft placement and coil embolization, with promising short- and long-term outcomes. In this report, we describe two cases of carotid artery pseudoaneurysm (after trauma and after carotid endarterectomy) treated successfully through transcarotid artery stenting using the flow reversal technique to minimize the risk of embolization and stroke.

Proximal embolic protection versus distal filter protection versus combined protection in carotid artery stenting: A systematic review and meta-analysis

OBJECTIVE

Proximal embolic protection devices (P-EPD) and distal filters (DF) are used to prevent distal cerebral embolizations during carotid artery stenting (CAS). We compared their comparative effectiveness in regards to prevention of intraprocedural and periprocedural adverse events, including ischemic lesions (ipsilateral and contralateral), stroke, transient ischemic attacks (TIA) and death. We also compared the combination of the two neuroprotection strategies vs. a single strategy in regards to ischemic lesions and stroke.

MATERIALS & METHODS

This study was performed according to the PRISMA and MOOSE guidelines and eligible studies were identified through search of PubMed, Scopus and Cochrane Central. A meta-analysis was conducted with the use of a random effects model. The I-square statistic was used to assess for heterogeneity.

RESULTS

Twenty-nine studies involving 16,307 patients were included. There was a significant reduction in ischemic lesions with the use of P-EPD among observational studies (RR: 0.66 [0.45-0.97]). There were no statistically significant differences for the other outcomes between the two treatment groups.

CONCLUSIONS

There is a number of studies reporting outcomes on the comparison between P-EPD and DF for CAS. P-EDP can reduce distal embolization phenomena resulting into ischemic lesions when compared to DF based on the results from real-world studies. P-EPD was not superior however, in regards to periprocedural stroke, TIA and death. Further studies are anticipated to provide a clear answer to this debate.

Proximal balloon occlusion versus distal filter protection in carotid artery stenting: A meta-analysis and review of the literature

INTRODUCTION

Carotid artery stenting (CAS) is typically performed using embolic protection devices (EPDs) as a means to reduce the risk of procedure-related stroke. In this study, we compared procedural morbidity and mortality associated with distal (D-EPD) vs. proximal (P-EPD) protection.

METHODS

MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were queried from January 1998 through May 2015. Only studies comparing (D-EPD) and (P-EPD) were included. Two independent reviewers selected and appraised studies and extracted data in duplicate. Random-effects meta-analysis was used to pool outcomes across studies. Heterogeneity of treatment effect among studies was assessed using the I² statistics. Publication bias was assessed using inspection of funnel plots. The primary endpoints included 30-day mortality and stroke. Secondary endpoints included new cerebral lesions on diffusion-weighted magnetic resonance imaging (DW-MRI) and contralateral lesions on DW-MRI.

RESULTS

A total of 12,281 patients were included from 18 studies (13 prospective and 5 retrospective) comparing (D-EPD) and (P-EPD) in the setting of CAS. The mean patient age was 69 years and 64% of patients were male. No evidence of publication bias was detected. There was no significant difference between the two modalities in terms of the risk of stroke (risk difference [RD] 0.0, 95% confidence interval [CI] -0.01 to 0.01) or mortality (RD 0.0, 95% CI -0.01 to 0.01) nor was there any difference in the incidence of new cerebral lesions on DW-MRI or contralateral DW-MRI lesions.

CONCLUSIONS

In patients undergoing CAS, both D-EPD and P-EPD provide similar levels of protection from peri-procedural stroke and 30 days mortality. © 2016 Wiley Periodicals, Inc.

Immunohistochemical Analysis of Debris Captured by Filter-Type Distal Embolic Protection Devices for Carotid Artery Stenting

BACKGROUND

Little is known about the micro-debris captured in filter-type distal embolic protection devices (EPD) used for carotid stenting (CAS). This study aimed to determine the histological and immunohistochemical characteristics of such debris by using a new liquid-based cytology (LBC) technique.

METHODS

Fifteen patients who underwent CAS using a filter-type distal EPD (FilterWire EZ; Boston Scientific, Marlborough, MA, USA) were included in the study. After gross inspection of each recovered filter device, micro-debris were collected using a new LBC technique (SurePath; TriPath Imaging, Inc., Burlington, NC). Histological and immunohistochemical analysis of the recovered debris was performed. The pre- and postoperative brain magnetic resonance imaging and neurological status of each patient were also reviewed.

RESULTS

No patient developed ipsilateral symptomatic stroke due to a thromboembolic event. All 15 patients (100%) had microscopically identifiable debris in the filters, whereas gross inspection detected visible debris only in 5 patients (33.3%). Histological analysis revealed various types of structural components in an advanced atheromatous plaque, including fragments of fibrous cap, calcified plaque, smooth muscle cells, and necrotic tissue fragment infiltrated with monocytes and macrophages.

CONCLUSIONS

Filter-type EPDs may contribute to reducing the risk of CAS-related embolic events by capturing micro-debris even when gross inspection of the recovered filter shows no visible debris in the device.

Proximal occlusion versus distal filter for cerebral protection during carotid stenting: updated meta-analysis of randomised and observational MRI studies

AIMS

Proximal occlusion (PO) and distal filter (DF) serve for cerebral embolic protection during carotid artery stenting (CAS). New cerebral lesions at diffusion-weighted magnetic resonance imaging (DW-MRI) represent a surrogate endpoint for embolisation, though their clinical impact is controversial. We performed a meta-analysis of randomised and observational DW-MRI studies comparing PO and DF during CAS.

METHODS AND RESULTS

We searched electronic scientific databases. The primary endpoint was the incidence of new cerebral lesions at DW-MRI; secondary endpoints were the incidence of new ipsilateral and new contralateral cerebral lesions at DW-MRI and death/cerebrovascular events (CVE). A total of 392 patients (seven studies) received CAS. At DW-MRI after 48 hours 178 patients (48.3%) presented new cerebral lesions. The use of PO versus DF reduced neither the risk of new cerebral lesions (OR [95% confidence interval] 0.65 [0.28-1.52], p=0.32) nor the risk of death/CVE (0.59 [0.22-1.60], p=0.30). Diabetes, baseline stenosis and symptoms significantly modified the risk estimates for new cerebral lesions.

CONCLUSIONS

In this meta-analysis, one half of patients receiving protected CAS developed new embolic cerebral lesions at DW-MRI, although the overwhelming majority were asymptomatic. Cerebral protection with PO versus DF neither reduced cerebral embolisation nor impacted on clinical outcomes.

Outcomes of 1000 Carotid Wallstent Implantations

Purpose: To evaluate the outcomes of carotid artery stenting (CAS) with Wallstents in a single-center experience. Methods: From January 2003 to December 2013, 1000 carotid artery lesions were treated with Carotid Wallstents under cerebral protection in 877 patients (mean age 71.7±8 years; 621 men). Indications for treatment were de novo lesions (>70% asymptomatic and >60% symptomatic); stenoses following carotid endarterectomy, radiation, or neck surgery; contralateral laryngeal nerve palsy; and high surgical risk. All the patients underwent duplex ultrasound and clinical evaluation during follow-up; radiography was performed when fracture or stent migration was suggested by ultrasound. Results: Procedure success was achieved in 99.3% of patients. Major and minor 30-day adverse events occurred in 2.1% of patients, including stroke (1.8%: 1.3% minor, 0.5% major), myocardial infarction (0.1%), and death (0.2%). Plaque morphology, nature of stenosis, and symptomatic status were significantly associated with the risk of postoperative neurologic events. Restenosis occurred in 3.2% at a mean 45.5-month follow-up and was significantly associated with diabetes, smoking, symptomatic stenosis, de novo stenosis, and calcification (plaque III/IV). No fracture or migration was registered during follow-up. Conclusion: CAS is a valid method for treating carotid artery disease, with very low rates of major adverse events and neurologic complications. The Carotid Wallstent seems to have excellent results, even with complex plaque morphology, and a low incidence of restenosis at follow-up.

What can be done for cerebral embolic protection in TAVI? Analysis in the light of 10 years' experience with protected carotid artery stenting

In the last 30 years, development of minimally invasive percutaneous procedures to treat cardiovascular defects has been thriving. Although these techniques present obvious advantages, like avoiding cardiopulmonary bypass, the passage of catheter systems and the deployment of devices in the blood circulation can cause particle embolization that may result in stroke. In carotid artery stenting, cerebral embolic protection devices (CEPD) such as filtering membranes have been available for already 10 years. In transcatheter aortic valve implantation (TAVI), the development of CEPD is starting and three membrane-based devices are in clinical trials. There are controversial discussions about the efficacy of CEPD in TAVI. The experience with CEPD in carotid artery stenting can help to understand some of the technical issues and shortcomings of current devices and thereby ultimately reduce cerebral complication risks during TAVI procedures.

Endarterectomy or carotid artery stenting: the quest continues part two

BACKGROUND

Although randomized trials on carotid artery stenting (CAS) could not establish its equivalence to carotid endarterectomy (CEA) in patients with symptomatic carotid disease, CAS is rapidly evolving. Data on long-term outcome after CAS from randomized trials have now become available and ongoing, prospectively held registries frequently publish their results in increasing numbers of patients. We have therefore reviewed the currently available literature and provide an update of our previous article on this topic.

DATA SOURCES

PubMed literature searches were performed to identify relevant studies regarding current status of CEA and stenting for symptomatic carotid stenosis.

CONCLUSIONS

The efficacy of CAS in patients with symptomatic carotid artery stenosis remains unclear because of varying results in randomized trials. Although multiple registries do report promising results after CAS, peri-interventional stroke/death rates still exceed those rates currently found after CEA. Therefore, CEA remains the "gold standard" in treating these patients.

Surgery Versus Stenting in Symptomatic Patients

Symptomatic carotid artery stenosis is an important cause of stroke with significant morbidity and mortality. Revascularization with carotid endarterectomy reduces the recurrence of stroke and until recently was considered the gold standard of therapy. Carotid artery stenting has emerged as an alternative method of revascularization in both high-risk and standard-risk patients. This review appraises the role of surgery versus stenting for patients with symptomatic carotid stenosis.

Carotid Artery Stenting - Strategies to Improve Procedural Performance and Reduce the Learning Curve

Carotid artery stenting (CAS) remains an appealing intervention to reduce the stroke risk because of its minimal invasive nature. Nevertheless, landmark randomised controlled trials have not been able to resolve the controversies surrounding this complex procedure as the peri-operative stroke risk in a non-selected patient population still seems to be higher after CAS in comparison to carotid endarterectomy. What is more, these trials have highlighted that patient outcome after CAS is influenced by patient- and operator-dependant factors. The CAS procedure exhibits a definitive learning curve resulting in higher complication rates if the procedure is performed by inexperienced interventionists or in low-volume centres. This article will outline strategies to improve the performance of physicians carrying out the CAS procedure by means of proficiency-based training, credentialing, virtual reality rehearsal and optimal patient selection.