New distal embolic protection device the FiberNet® 3 dimensional filter: First carotid human study

Clinical Outcomes of Second- versus First-Generation Carotid Stents: A Systematic Review and Meta-Analysis

Background: Single-cohort studies suggest that second-generation stents (SGS; “mesh stents”) may improve carotid artery stenting (CAS) outcomes by limiting peri- and postprocedural cerebral embolism. SGS differ in the stent frame construction, mesh material, and design, as well as in mesh-to-frame position (inside/outside). Objectives: To compare clinical outcomes of SGS in relation to first-generation stents (FGSs; single-layer) in CAS. Methods: We performed a systematic review and meta-analysis of clinical studies with FGSs and SGS (PRISMA methodology, 3302 records). Endpoints were 30-day death, stroke, myocardial infarction (DSM), and 12-month ipsilateral stroke (IS) and restenosis (ISR). A random-effect model was applied. Results: Data of 68,422 patients from 112 eligible studies (68.2% men, 44.9% symptomatic) were meta-analyzed. Thirty-day DSM was 1.30% vs. 4.11% (p < 0.01, data for SGS vs. FGS). Among SGS, both Casper/Roadsaver and CGuard reduced 30-day DSM (by 2.78 and 3.03 absolute percent, p = 0.02 and p < 0.001), whereas the Gore stent was neutral. SGSs significantly improved outcomes compared with closed-cell FGS (30-day stroke 0.6% vs. 2.32%, p = 0.014; DSM 1.3% vs. 3.15%, p < 0.01). At 12 months, in relation to FGS, Casper/Roadsaver reduced IS (−3.25%, p < 0.05) but increased ISR (+3.19%, p = 0.04), CGuard showed a reduction in both IS and ISR (−3.13%, −3.63%; p = 0.01, p < 0.01), whereas the Gore stent was neutral. Conclusions: Pooled SGS use was associated with improved short- and long-term clinical results of CAS. Individual SGS types, however, differed significantly in their outcomes, indicating a lack of a “mesh stent” class effect. Findings from this meta-analysis may provide clinically relevant information in anticipation of large-scale randomized trials.

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.

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.

Carotid artery stenting for primary and secondary stroke prevention

BACKGROUND

Carotid artery disease is a major cause of the disability and mortality associated with strokes. Ischemic stroke remains the major cause of adult disability and third-leading cause of adult mortality, and carotid revascularization currently remains the principal surgical tool in the prophylaxis of this disease.

METHODS

The literature representing the current body of evidence for carotid revascularization and the authors' current practices in the management of this disease are summarized in this review.

RESULTS

We provide an evidence-based narration of the development and current status of carotid artery stenting (CAS) by reviewing 1) the evidence for carotid revascularization from early carotid endarterectomy (CEA) trials; 2) the randomized trials comparing CEA and CAS, with a special emphasis on the recently published results of the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST), which have been a "game-changer," tipping the balance towards accepting CAS as a safe, equally effective, and durable alternative to CEA for all patients requiring carotid revascularization; and 3) the technical advances in CAS after enrollment of patients in the CREST.

CONCLUSIONS

CAS and CEA are complementary procedures. Judicious selection of the procedure is made on a case-by-case basis.

Safety and effectiveness of the INVATEC MO.MA proximal cerebral protection device during carotid artery stenting: results from the ARMOUR pivotal trial

OBJECTIVE

The multicenter ARMOUR (ProximAl PRotection with the MO.MA Device DUring CaRotid Stenting) trial evaluated the 30-day safety and effectiveness of the MO.MA Proximal Cerebral Protection Device (Invatec, Roncadelle, Italy) utilized to treat high surgical risk patients undergoing carotid artery stenting (CAS).

BACKGROUND

Distal embolic protection devices (EPD) have been traditionally utilized during CAS. The MO.MA device acts as a balloon occlusion "endovascular clamping" system to achieve cerebral protection prior to crossing the carotid stenosis.

METHODS

This prospective registry enrolled 262 subjects, 37 roll-in and 225 pivotal subjects evaluated with intention to treat (ITT) from September 2007 to February 2009. Subjects underwent CAS using the MO.MA device. The primary endpoint, myocardial infarction, stroke, or death through 30 days (30-day major adverse cardiac and cerebrovascular events [MACCE]) was compared to a performance goal of 13% derived from trials utilizing distal EPD.

RESULTS

For the ITT population, the mean age was 74.7 years with 66.7% of the cohort being male. Symptomatic patients comprised 15.1% and 28.9% were octogenarians. Device success was 98.2% and procedural success was 93.2%. The 30-day MACCE rate was 2.7% [95% CI (1.0-5.8%)] with a 30-day major stroke rate of 0.9%. No symptomatic patient suffered a stroke during this trial.

CONCLUSIONS

The ARMOUR trial demonstrated that the MO.MA(R) Proximal Cerebral Protection Device is safe and effective for high surgical risk patients undergoing CAS. The absence of stroke in symptomatic patients is the lowest rate reported in any independently adjudicated prospective multicenter registry trial to date.

Carotid artery stenting in high surgical risk patients using the FiberNet embolic protection system: the EPIC trial results

OBJECTIVE

The multicenter EPIC (FiberNet Embolic Protection System in Carotid Artery Stenting Trial) single-arm trial evaluated the 30-day outcomes of a new design concept for embolic protection during carotid artery stenting (CAS).

BACKGROUND

Embolic protection filters available for use during CAS include fixed and over-the-wire systems that rely on embolic material capture within a "basket" structure. The FiberNet Embolic Protection System (EPS), which features a very low crossing profile, consists of a three-dimensional fiber-based filter distally mounted on a 0.014 inch guidewire with integrated aspiration during filter retrieval.

METHODS

The trial enrolled 237 patients from 26 centers. Demographics, clinical and lesion characteristics, as well as adverse events through a 30-day follow-up were recorded. The mean age of the patients was 74 years, 64% were male and 20% had symptomatic carotid artery disease.

RESULTS

The combined major adverse event (MAE) rate at 30 days for all death, stroke, and myocardial infarction was 3.0%. There were three major strokes (two ischemic and one hemorrhagic) and two minor strokes (both ischemic) for a 2.1% 30-day stroke rate. The procedural technical success rate was 97.5% and macroscopic evidence of debris was reported in 90.9% of the procedures.

CONCLUSIONS

The FiberNet EPS, used with commercially available stents, produced low stroke rates following CAS in high surgical risk patients presenting with carotid artery disease. The unique filter design including aspiration during retrieval may have contributed to the low 30-day stroke rate reported during CAS in patients considered at high risk for complications following carotid endarterectomy (CEA).

In vitro performance assessment of distal protection filters: pulsatile flow conditions

PURPOSE

To evaluate in vitro the capture efficiency of a distal protection filter (DPF) used during carotid artery stenting and examine the longitudinal vascular impedance in the presence of a DPF.

METHODS

Four approved DPFs (Spider RX, FilterWire EZ, RX Accunet, and FiberNet) were evaluated in a physiologically realistic in vitro setup. A pulsatile programmable piston pump circulated a blood analog at a time-varying flow rate representative of the human common carotid artery. A silicone carotid bifurcation having average human dimensions was used for the carotid flow model. Microspheres ranging from 40 to 900 microm were injected to simulate embolization. The longitudinal vascular impedance was calculated as the ratio of the time-varying pressure gradient across the DPF to the time-varying flow rate in the internal carotid artery.

RESULTS

RX Accunet had the highest capture efficiency (99.4%) and Spider RX the lowest (78.1%). Spider RX increased the longitudinal vascular impedance the least after deployment (+23%), while FilterWire EZ increased the longitudinal vascular impedance the least after particles were injected (+29%). FiberNet increased longitudinal vascular impedance the most (+84%).

CONCLUSION

This investigation, unique for examining the effects of physiologically realistic pulsatile flow on DPF performance, can aid in the development of future generations of novel DPFs.

How to avoid complications associated with carotid angioplasty and stenting

Carotid angioplasty and stenting (CAS) has been proposed as an alternative to surgery and is now performed more frequently and is well accepted, at least for high surgical risk patients. However, complications and particularly embolic strokes, even with a meticulous technique, can occur at any step of the procedure. Silent embolism is detected after CAS and may be a problem that needs to be discussed. To avoid and reduce these complications associated with CAS, it is important to have good indications dependent upon on good patient and lesions selection, as well as correct technique. New parameters have been proposed, particularly for asymptomatic lesions. The authors consider that embolic protection devices (EPDs) are mandatory for CAS, and new techniques will be presented. The choice of the EPD depends on the clinical status of the patient, the lesion morphology and characteristics, and the anatomy of the artery. All stents are not equivalent and so a good choice of the stent is necessary to avoid and reduce the complications associated with CAS, and experienced operators are also needed. With all these considerations, CAS can now be performed with acceptable outcomes and in certain population the results are comparable or superior to surgery. The results of ongoing randomized trials are awaited.

Do the Advantages of the FiberNet(®) Embolic Protection Device Translate into Technical Success and Comparable Event Rates in Carotid Artery Stenting?

FiberNet(®) is a second generation non-conventional embolization protection device (EPD) that purports to offer several advantages: ability to capture debris as small as 40 μm, more flexibility with placement and positioning in curved segments requiring a small landing zone, ability to conform to asymmetric vessels, and improved deliverability. The design features a low profile with large surface area to capture debris. Legitimate concerns include inducement of obstruction or low flow with debris capture and requirements in the IFU to aspirate during re-capture and device removal. Our goal was to compare the results of carotid artery stenting (CAS) using FiberNet(®) against a multi-center experience of CAS using other filter devices to identify any differences in technical success or event rates. FiberNet(®) (n=25) results were compared to all CAS cases performed at the Mayo Clinic in Rochester, MN, St Mary's/Duluth Clinic in MN, and North Central Heart Institute in Sioux Falls, SD (n=250) from March 2001 to December 2008. Chi-square or means were used to compare variables, as appropriate. Bivariate logistic regression was used to identify possible correlates of adverse outcome. Statistical significance was set at < 0.05. FiberNet(®) patients were more likely to be older (78.1+5.4 vs 73.6+9.4, p=0.019), female (48% vs 29%, p=0.047), and have peripheral vascular disease (84.0% vs 37.2%, p=0.025), and less likely to have diabetes (8.0% vs 29.8%, p=0.012) than patients in the comparison group. FiberNet(®) patients had more lesion calcification (40.0% vs 18.9%, p=0.014) and increased number of type 2 and 3 arches (44.2% vs 73.9%, p=0.006). Procedural success rate was 100% in both groups. None of the FiberNet(®) patients showed evidence of stagnant flow. The thirty-day outcome for TIA, CVA, or death was 4% in FiberNet(®) versus 4.8% in the comparison group (p NS). None of the independent variables - age gender, serum creatinine, arch complexity, lesion length, lesion calcium, lesion thrombus, PVD, diabetes, contralateral carotid occlusion, or ipsilateral carotid endarterectomy - predicted adverse events. Although FiberNet(®) patients had more lesion calcium and more challenging arch anatomy, procedural success and adverse events were comparable between groups. The advantages of FiberNet(®) can be applied to CAS with good technical results and may be a promising EPD for certain high-risk situations.

Carotid stenting with embolic protection: evolutionary advances

Stroke is one of the most significant causes of death and morbidity worldwide. Atherosclerotic stenosis of the extracranial internal carotid artery has been invoked as a common causative factor for stroke in over 20% of patients. Although medical therapy can help to prevent the onset and progression of carotid arteriosclerosis, open surgical carotid endarterectomy has been the gold standard for treating severe blockage. Carotid artery stenting has recently demonstrated efficacy in stroke prevention from atherosclerosis, and in high-risk surgical subgroups, has been shown to be associated with a reduction in the risk of myocardial infarction. The controversy for carotid stenting surrounds the incidence of periprocedural stroke. Will embolic protection devices (EPDs) decrease this risk? EPDs continue to evolve with various engineering strategies directed at increasing the efficiency of protection. There are two major categories of EPDs: distal occlusion, either with balloons (e.g., Percusurge, Medtronic Corporation, MN, USA); or distal filtration (e.g., Angioguard, Cordis Corporation, NJ, USA). The second method is proximal protection (e.g., MoMA device, Invatec Corporation, Brescia, Italy). We review the results of trials currently evaluating carotid stenting with both distal and proximal embolic protection.