Use Of Embolic Protection Devices Research Articles

Embolic Protection and Platelet Inhibition During Renal Artery Stenting

Preservation of renal function is an important objective of renal artery stent procedures. Although atheroembolization can cause renal dysfunction during renal stent procedures, whether adjunctive use of embolic protection devices or glycoprotein IIb/IIIa inhibitors improves renal function is unknown. One hundred patients undergoing renal artery stenting at 7 centers were randomly assigned to an open-label embolic protection device, Angioguard, or double-blind use of a platelet glycoprotein IIb/IIIa inhibitor, abciximab, in a 2x2 factorial design. The main effects of treatments and their interaction were assessed on percentage change in Modification in Diet in Renal Disease-derived glomerular filtration rate from baseline to 1 month using centrally analyzed creatinine. Filter devices were analyzed for the presence of platelet-rich thrombus. With stenting alone, stenting and embolic protection, and stenting with abciximab alone, glomerular filtration rate declined (P<0.05), but with combination therapy, it did not decline and was superior to the other allocations in the 2x2 design (P<0.01). The main effects of treatment demonstrated no overall improvement in glomerular filtration rate; although abciximab was superior to placebo (0+/-27% versus -10+/-20%; P<0.05), embolic protection was not (-1+/-28% versus -10+/-20%; P=0.08). An interaction was observed between abciximab and embolic protection (P<0.05), favoring combination treatment. Abciximab reduced the occurrence of platelet-rich emboli in the filters from 42% to 7% (P<0.01). Renal artery stenting alone, stenting with embolic protection, and stenting with abciximab were associated with a decline in glomerular filtration rate. An unanticipated interaction between Angioguard and abciximab was seen, with combination therapy better than no treatment or either treatment alone.

The role of thrombectomy and distal protection devices during percutaneous coronary interventions

Achievement of the angiographic gold standard TIMI 3 flow (Thrombolysis in Myocardial Infarction) flow grade during PCI (percutaneous coronary intervention) in the setting of AMI (acute myocardial infarction) is insufficient for attainment of optimal prognostic benefit, as there is a poor prognosis for patients with evidence of inadequate flow at the tissue level despite patent coronary arteries. PCI in lesions containing thrombus are associated with an increased risk of complications occurring through dislodgement of thrombotic material resulting and distal embolisation leading to slow flow or even no-reflow. Devices which remove thrombus from coronary arteries (thrombectomy devices) or protect from distal embolisation of thrombus (distal protection devices) are increasingly used in PCI. We have performed a systematic review of the literature to investigate the role of these devices in PCI in the setting of AMI. Use of thrombectomy devices in randomised and multicentre trials in patients undergoing PCI during STEMI is associated with a significant benefit in a number of markers of myocardial perfusion including MBG (myocardial blush grade), ST segment resolution and improvement of distal embolisation, although no significant benefits in mortality have been observed. There does not appear to be strong evidence for the use of embolic protection devices and distal filter devices in the setting of primary PCI in native coronary arteries, although evidence from trials such as the SAFER trial would make a strong case for their use in SVG interventions.

Embolic Protection in Infrainguinal Interventions

The benefits of the use of embolic protection devices (EPDs) in saphenous vein coronary artery bypass grafts and carotid arteries have been shown, but the utility of their application during infrainguinal endovascular interventions is somewhat unclear. Patients with specific anatomical features or lesion characteristics, or patients undergoing specific types of endovascular interventions may benefit from the off-label use of EPDs, but this has yet to be determined. This report will examine the current literature related to the use of EPDs in infrainguinal endovascular interventions and attempt to identify the patients who would most likely benefit from their use. In addition, the setting in which EPDs have been used at one institution is briefly described. This discussion will serve as a general guideline for the use of EPDs and act as an impetus for the development of future clinical trials to help elucidate the patients who will truly benefit from EPDs use when undergoing lower extremity endovascular revascularization procedures.

Expanding Use of Embolic Protection Devices

Embolic protection devices were initially developed for the treatment of saphenous vein aorto-coronary bypass graft stenosis due to the significant risk of atheroembolism, and their use is well accepted. The use of these devices for carotid arterial interventions is also well accepted due to the significant consequences of embolization in the cerebral circulation. The use of these devices is extending to other vascular beds to include the renal arteries and lower extremities. We review the basic principles of these devices and their uses in various vascular beds based on our own experience as well as that in the literature.

Saphenous Vein Graft Stenting and Major Adverse Cardiac Events

Treatment of saphenous vein graft (SVG) stenosis with percutaneous coronary intervention has a 15% to 20% incidence of major adverse cardiac events (MACE) within 30 days. Although MACE rates are reduced significantly by the use of embolic protection devices (EPDs), neither the level of baseline risk nor the benefit provided by EPDs has been well characterized. Data from 5 randomized controlled trials and 1 registry evaluating EPDs in SVG percutaneous coronary intervention (n=3958 patients) were pooled for analysis. MACE was defined as a composite of death, myocardial infarction, and target vessel revascularization. Baseline variables and 2 summary angiographic variables (an SVG degeneration score and an estimate of lesion plaque volume) were included in a multivariable logistic regression model to predict 30-day MACE, with adjustment for the type of device used and inter-study variation. The angiographic variables were potent predictors of MACE (increasing SVG degeneration score, P<0.0001; larger estimated plaque volume, P<0.0001), with significant contributions from the presence of thrombus (P<0.01), increasing patient age (P<0.01), glycoprotein IIb/IIIa inhibitor use (P=0.02), and current tobacco abuse (P=0.03). The treatment benefit of EPDs was preserved across all categories of risk as categorized by SVG degeneration or plaque volume. The strongest predictors of 30-day MACE in SVG percutaneous coronary intervention are angiographic estimates of plaque volume and SVG degeneration. Identification of these predictors of 30-day MACE allows reliable prediction of patient outcomes and confirms consistent treatment benefit with the use of EPDs across the range of patients tested in randomized trials.

The Role of Embolic Protection Devices in Renal Artery Stenting

Renal artery angioplasty and stenting is commonly performed for the treatment of hypertension and ischemic nephropathy. An increasing number of procedures are being undertaken for "renal preservation" despite an associated risk of renal function decline related to the embolization of atheromatous debris liberated during the procedure. Although smaller, more flexible guidewires and stents have been developed to decrease the amount of debris created, interest in the off-label use of embolic protection devices has increased. We review the available embolic protection devices and currently available data regarding their use in renal artery interventions. Although not designed for use in the renal artery, there are at least theoretical reasons to believe that embolic protection during renal artery angioplasty may improve outcomes.

The type of embolic protection does not influence the outcome in carotid artery stenting

The goal of this study was to review our experience with embolic protection devices (EPDs) during carotid artery stenting (CAS). Specifically, we aimed to verify their clinical effectiveness and to compare clinical outcomes between specific devices and types of EPDs. The CAS databases at four participating centers were reviewed. Adverse events were defined as death, stroke (>24 hours), or transient ischemic attack (TIA) (<24 hours). We compared the risk of procedural and 30-day events between patients treated with and without an EPD. We also compared these risks between different EPDs and between the different types of EPDs. A total of 3160 CAS procedures using nine EPDs were analyzed. The risk of a procedural adverse event was 0.9% in protected and 2.3% in unprotected procedures (P = .12). Compared with the most frequently used device (FilterWire, Boston Scientific, Natick, Mass), there was no significant difference in the risk of procedural adverse events for any of the other EPDs. There was, however, an increased risk of 30-day adverse events with the Accunet (Abbott Vascular, Redwood, Calif) filter compared with the FilterWire (relative risk [RR] 2.67, confidence interval [CI] 1.41 to 5.04, P = .005). Pairwise comparison of proximal occlusion balloons to filters, distal occlusion balloons to filters, and proximal to distal occlusion balloons revealed no significant difference in the risk of procedural or 30-day adverse events. There was no significant difference in risk of procedural events between eccentric and concentric filters, however, the relative risk of eccentric compared with concentric filters at 30 days was 0.59 (unadjusted, CI 0.38 to 0.92, P = .04). This difference was still apparent after adjustment for risk factors (RR 0.61, CI 0.39 to 0.95, P = .06), but not after adjustment for risk factors and stent-type [(open-cell vs closed-cell) RR 0.76, CI 0.47 to 1.22, P = .51]. The use of EPDs is associated with a low risk of procedural adverse events. We were unable to detect significant differences in risks of procedural adverse events between different devices or types of devices. We speculate that the observed differences seen at 30 days are largely attributable to differences in stent-type used.

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

Evaluate the performance and safety of the FiberNet Embolic Protection System during carotid artery intervention. Carotid Angioplasty and Stenting (CAS) can be proposed to treat the majority of carotid stenoses. Brain embolization takes place and routine use of Embolic Protection Devices (EPD) is warranted. Many EPDs have significant limitations, which may be addressed by a new EPD, the FiberNet (Lumen Biomedical, Plymouth, MN). The system consists of a 3-dimensional expandable filter made of fibers, which expand radially, mounted onto a 0.014'' wire and retrieval catheter. FiberNet can capture particles as small as 40 microm without compromising flow. 35 lesions treated in 34 patients. Male 67.6%. Age: 71.4 +/- 8.8 (50-85). Average stenosis 84.5% +/- 7.9 (70-99). 29.4% were symptomatic. Technical success: 34/35 (97%). No stroke or death within 30 days. Neurological events: two permanent amaurosis, one amaurosis fugax. All samples visually contained significant amounts of emboli. The mean surface area of debris caught was 63.8 mm(2) (37.7-107.5). Comparisons were made with other EPDs. The mean surface area of debris caught was 12.2 mm(2) (2.7-34.3). No changes were noted in CT/MRI at 30-day post procedure. The first human use of this new novel EPD in carotid artery stenting is encouraging. The FiberNet was easy to use and confirmed the ability to capture particles less than 100 microm. The feasibility of the FiberNet has been demonstrated. Additional patients will demonstrate the overall safety and efficacy of this new EPD device.

Mechanical thrombectomy options in complex percutaneous coronary interventions

Percutaneous coronary interventions (PCI) of thrombus-containing lesions are associated with an increased risk of acute complications and poorer long term vessel patency. Dealing with these vessels provides many technical challenges, especially with the significant risk of coronary no reflow and distal embolization. Pharmacological strategies, including intravenous and intracoronary glycoprotein IIbIIIa inhibitors reduce intracoronary thrombus propagation, improve TIMI flow and are associated with a reduction in adverse event rates. Mechanical strategies (particularly embolic protection and thrombectomy catheters) help to improve coronary blood flow and myocardial perfusion. However, their impact on clinical outcomes is less clear. The use of embolic protection devices is associated with better perfusion, blood flow, and clinical outcomes among patients undergoing saphenous vein graft (SVG) PCI. However, the role for these devices in primary PCI and native coronary artery interventions is uncertain. This study examines the current approaches to manage thrombotic lesions during PCI and reviews the evidence in support of the different mechanical thrombectomy options that are available to the interventional cardiologist.

Effective prevention of massive periprocedural embolism during renal artery stenting

We report the case of a massive embolism of atheromatous material during stenting of a tight renal artery stenosis, which was prevented by using a distal embolic protection device and aggressive aspiration of the blood through a guiding catheter. A 72-year-old man who was referred to our institution for coronary artery disease treated with coronary angioplasty underwent renal angiography which revealed a tight stenosis (99%) located at the ostium of the right renal artery extending for 15 mm into the main tract. The diameter of the artery was estimated to be 5.5 cm in the main tract, and the plaque had a soft appearance complicated by the presence of a thrombus (persistence of contrast agent in the plaque on selective renal angiography). Renal artery Doppler ultrasound and renal scintigraphy confirmed the need for renal revascularization. An embolus protection device (FilterWire EZ, Boston Scientific, Natick, MA, USA) was successfully opened distally to the stenosis after gentle predilation. After stent deployment (Genesis 5.5x18 mm, Cordis, J&J Medical, Miami Lakes, FL, USA), aggressive aspiration of the blood through the guiding catheter was performed. A large amount of embolic material with macroscopic particles was retrieved into the basket of the embolic protection device and in the blood aspirated with the guiding catheter. Good functional results were obtained on Doppler analysis of intrarenal blood flow, with a resistive index of 70. Despite the fact that the extensive use of embolic protection devices in renal artery stenting is still under discussion, this technique may be advisable in selected cases with favorable anatomy and high embolic risk, especially in patients with complex and hazy lesions.

Pivotal, randomized U.S. study of the Symbiot™ covered stent system in patients with saphenous vein graft disease: Eight‐month angiographic and clinical results from the Symbiot III trial

The purpose of this study was to evaluate the clinical and angiographic outcomes of the Symbiot ePTFE covered stent versus bare metal stents (BMS) for the treatment of saphenous vein graft (SVG) disease. The Symbiot stent was developed to reduce periprocedural complications, by potentially preventing distal embolization, and to serve as a possible barrier to cell migration, thus reducing restenosis. Symbiot III is a prospective, randomized trial of 400 patients at 45 US sites, with 201 patients in the Symbiot group and 199 in the BMS group. Randomization was stratified based on the intended use of embolic protection devices and glycoprotein IIb/IIIa inhibitors. The primary endpoint was percent diameter stenosis (%DS) as measured by quantitative coronary angiography at 8 months. Secondary endpoints included MACE (cardiac death, MI, TVR). The groups were well matched for all baseline clinical and lesion characteristics. At 8 months, %DS was comparable between groups (30.9% Symbiot, 31.9% BMS, P = 0.80). Although the rates of binary restenosis in the stented segment were similar (29.1% Symbiot, 21.9% BMS, P = 0.17), more patients in the Symbiot group had binary restenosis at the proximal edge (9.0% Symbiot, 1.8% BMS, P = 0.0211). There was no difference in the incidence of MACE between groups (30.6% Symbiot, 26.6% BMS, P = 0.43). This study failed to show an advantage for the Symbiot stent in the treatment of degenerated SVGs. This PTFE covered stent does not appear to act as a barrier to prevent restenosis.

Leukocyte count predicts microembolic Doppler signals during carotid stenting: A link between inflammation and embolization

Conclusion: Microembolic signals during carotid stenting are increased with increased preprocedure leukocyte counts. Summary: Microembolization detected by transcranial Doppler imaging inevitably accompanies carotid artery stenting. The authors chose to study the relationship between microembolization during carotid artery stenting and preprocedure leukocyte count. Forty-three patients underwent simultaneous transcranial Doppler monitoring of the middle cerebral artery during carotid artery stenting. Microembolic signals detected by transcranial Doppler were used to quantify microembolization. Preprocedure leukocyte counts were then related to microembolic signals detected by transcranial Doppler. The preprocedure leukocyte count in an unadjusted analysis was correlated positively with total procedure microembolic signals (R2= 0.16; P = .008). With adjustments for age, comorbidities, gender, medical therapies, and use of embolic protection devices, increasing leukocyte count (β = 35 for each 1000/μL increment; P = .018) remained an independent and significant predictor of microembolization (model-adjusted R2 = 0.365; P = .0005). The relationship with increased leukocyte count was most marked in the third tertile of the leukocyte count, with a median number of microembolic signals being 259 in the first tertile, 276 in the second tertile, and 350 in the third tertile leukocyte count. Embolic protection devices were used in 16% of the population. Overall, 12% of the patients died, had a myocardial infarction, or had a stroke. For every 1000/μL increase in leukocyte count, transcranial Doppler detected 35 additional microembolic signals. Comment: The association of increased leukocyte count with microembolic signals during carotid stenting is interesting. However, the patients reported in this series are unlikely representative of current practice in that only 16% underwent carotid stenting with cerebral protection devices. The 12% major procedural complication rate also seems high. Finally, the only marker of inflammation used in this retrospective study was leukocyte count. Further data using modern techniques and additional markers of inflammation such as C-reactive protein are required before a link can be established between inflammation and microembolization during carotid artery stenting.

Leukocyte count predicts microembolic Doppler signals during carotid stenting: A link between inflammation and embolization

Conclusion: Microembolic signals during carotid stenting are increased with increased preprocedure leukocyte counts. Summary: Microembolization detected by transcranial Doppler imaging inevitably accompanies carotid artery stenting. The authors chose to study the relationship between microembolization during carotid artery stenting and preprocedure leukocyte count. Forty-three patients underwent simultaneous transcranial Doppler monitoring of the middle cerebral artery during carotid artery stenting. Microembolic signals detected by transcranial Doppler were used to quantify microembolization. Preprocedure leukocyte counts were then related to microembolic signals detected by transcranial Doppler. The preprocedure leukocyte count in an unadjusted analysis was correlated positively with total procedure microembolic signals (R2 = 0.16; P = .008). With adjustments for age, comorbidities, gender, medical therapies, and use of embolic protection devices, increasing leukocyte count (β = 35 for each 1000/μL increment; P = .018) remained an independent and significant predictor of microembolization (model-adjusted R2 = 0.365; P = .0005). The relationship with increased leukocyte count was most marked in the third tertile of the leukocyte count, with a median number of microembolic signals being 259 in the first tertile, 276 in the second tertile, and 350 in the third tertile leukocyte count. Embolic protection devices were used in 16% of the population. Overall, 12% of the patients died, had a myocardial infarction, or had a stroke. For every 1000/μL increase in leukocyte count, transcranial Doppler detected 35 additional microembolic signals. Comment: The association of increased leukocyte count with microembolic signals during carotid stenting is interesting. However, the patients reported in this series are unlikely representative of current practice in that only 16% underwent carotid stenting with cerebral protection devices. The 12% major procedural complication rate also seems high. Finally, the only marker of inflammation used in this retrospective study was leukocyte count. Further data using modern techniques and additional markers of inflammation such as C-reactive protein are required before a link can be established between inflammation and microembolization during carotid artery stenting.

EMERALD, AIMI, and PROMISE: is there still a potential for embolic protection in primary PCI?

The recent trials of routine use of embolic protection devices for primary percutaneous coronary interventions (PCI) (the EMERALD, PROMISE, and AIMI trials) have demonstrated neutral or even negative effects of these devices on myocardial reperfusion and final infarct size. Despite these results, there is still ground to believe that PCI-induced embolization may be clinically relevant in specific subsets of patients with acute myocardial infarction (AMI). Significant clinical consequences may be expected when embolization is quantitatively relevant and/or is qualitatively characterized by lipid-rich athero-embolism (as is the case of lipid core embolization through the ruptured cap of a fibro-atheroma). Future trials on embolic protection devices in primary PCI should adopt a selective, rather than a routine strategy, through the identification, by angiographic or intravascular imaging parameters, of patients at highest risk of clinically relevant embolization. Such trials should also adopt specific endpoints able to evaluate the effect of micro-embolization, which is currently far from optimally assessed by the standard markers of myocardial reperfusion.

The role of thrombectomy and embolic protection devices

In recent years, it has been demonstrated that restoration of normal coronary flow in the infarct-related artery is not equivalent to the restoration of myocardial perfusion through cardiac microcirculation. Among patients with ST-segment elevation myocardial infarction (STEMI) who undergo primary percutaneous coronary intervention (PCI), distal embolization and slow-flow and no-flow phenomenon occur in ∼30% of patients. In these patients, PCI results are less satisfactory, with lower thrombolysis in myocardial infarction (TIMI) or myocardial blush grade (MBG) values, lower rate of a complete resolution of ST-segment elevation, lower left ventricular ejection fraction, and poorer long-term outcome. Studies investigating the usefulness of thrombectomy systems in STEMI showed a similar proportion of patients with TIMI (flow grade 3) in the infarct-related artery in thrombectomy treated patients and control groups. Some small studies with thrombectomy systems or distal protection devices showed encouraging results with preventing slow-flow, no-reflow, and distal embolization, as measured by improved myocardial perfusion by angiography and improved ST-segment elevation resolution after PCI. Large, multi-centre studies did not confirm clinical benefit. New European Society of Cardiology PCI guidelines do not give definitive recommendations regarding the use of embolic protection devices for this group of patients. More randomized trials are needed. However, thrombectomy may be very effective in the situation of large thrombus bulk when present after first balloon catheter inflation. It could be also potentially effective with easy to use thrombectomy system for replacing balloon pre-dilatation before stenting, if studies could prove clinical benefit of such concept for primary PCI.

Carotid artery stenting: experience of a single institute in china.

Concern regarding the safety of Carotid angioplasty and stenting (CAS) exists because of the risk of cerebral embolization during the procedure. The purpose of this article is to discuss that technology modification may improve the outcomes of this procedure. Between October 1997 and October 2004, 439 consecutive patients with 478 stenotic carotid arteries were treated. 284 vessels were stented without the use of embolic protection devices and 194 vessels with protection. Among cases not using protection device, 201 arteries were stented with predilation alone, 63 with postdilation alone, six with both pre- and post-dilation, two with neither and twelve were stented with balloon expandable stents. The technical success of 100%.The combined stroke and death rate during the procedure and the 30-day follow-up at 30 days was 1.67% overall. Three (0.63%) deaths occurred; one was due to a major infarction secondary to stent breakage, and two died of massive reperfusion intracerebral haemorrhage. There were total six ischemic stroke, of the five ischemic strokes wich developed in nonprotection group, two were among 201 cases with predilation alone (0.99%), which developed after stent deployment and postprocedure, and three among 63 cases with postdilation alone (4.76%), which developed immediately after postdilation. The incidence of ischemic stroke was lower among those who were stented with predilation alone than among those who were stented with postdilation alone. This likely results from reduced intimal injury and decreased risk of embolic complications.

Carotid artery stenting in clinical practice

Carotid artery stenting (CAS) for symptomatic and asymptomatic carotid stenosis seems to be on the doorstep of more widespread use. However, its feasibility and safety in clinical practice at a broad spectrum of hospitals needs to be determined. We analyzed data of the prospective multi-centre Carotid Artery Stenting (CAS) Registry of the German Arbeitsgemeinschaft Leitende Kardiologische Krankenhausarzte (ALKK). From 7/1996 to 5/2004 1888 patients from 28 hospitals were included in the CAS Registry. The median hospital stay from CAS until hospital discharge was 3 days (quartiles: 2-6 days). Median patients age was 70 years (quartiles: 64-76 years) with 72.1% males. CAS for symptomatic stenosis was performed in 55% of cases. Patients treated with CAS suffered from coronary artery disease in 66.5%, had arterial hypertension in 91.7%, hyperlipidemia in 86.3% and 34.2% were diabetics. The intended CAS procedure was completed in 98.1% of cases. A stent was implanted in 97.3% of completed cases. The median intervention time was 43 min (quartiles: 30-60 min). During the hospital stay death rate was 0.3% (5/1888) and the rate of ipsilateral stroke 3.2% (58/1840). A contralateral ischemic event occurred in 1.4% (26/ 1840) of patients. The combined rate of all death or strokes was 3.8% (70/1841). Between 1996 and 2004 there was a steady increase in the use of protection devices during CAS (0% in 1996 and 97.9% in 2004; p for trend <0.0001). There was also an increase in the proportion of patients treated for asymptomatic stenoses (p for trend <0.0001). We observed a decrease of the combined endpoint of death or stroke from 6.3% in 1996 to 1.9% in 2004 (p for trend=0.021). The multi-centre ALKK CAS Registry data confirm the feasibility and shot-term safety of CAS even in daily clinical practice. There was a rapid penetration of the use of embolic protection devices, an increase in treatment of asymptomatic carotid stenoses and a decrease in acute complication rates from 1996 to 2004.

Intracoronary Thrombectomy During Percutaneous Coronary Intervention in Acute Myocardial Infarction – Technology Showcase or True Need?

Thrombectomy for patients with ST elevation myocardial infarction (STEMI) is an evolving issue. Randomised studies on suction and thrombectomy devices in a whole spectrum of STEMI patients provide conflicting results. New European Society of Cardiology (ESC) percutaneous coronary intervention (PCI) guidelines do not give definitive recommendations regarding the use of embolic protection devices for this group of patients.

A refined angioplasty and stenting technique may offer an alternative to carotid endarterectomy.

Strokes are the third leading cause of death in the United States. Carotid artery occlusive disease accounts for about 20% to 30% of all strokes. Carotid endarterectomy has been the traditional standard treatment for patients with significant carotid artery disease. However, surgical therapy is associated with significant complications. Carotid angioplasty and stenting offers an attractive alternative to surgery. There have been significant advances in this field including the use of embolic protection devices. In this article, we review the current literature addressing the role of endovascular interventions in the management of patients with significant carotid stenosis.

Role of distal protection during carotid stenting.

The most common complication of carotid angioplasty is distal embolization of debris and/or thrombus. The only way to avoid this complication is with the use of embolic protection devices. Several filters, distal balloon occlusion devices, and proximal balloon occlusion devices are available. These devices make it possible to capture arteriosclerotic debris during angioplasty and stenting. During the majority of procedures at least some particles can be retrieved. Therefore there is no doubt that these devices are important for carotid angioplasty. However, due to the low complication rate of carotid angioplasty even without embolic protection devices, large randomized trials are necessary to statistically prove the clinical efficacy of these devices.