FilterWire EZ Research Articles

Case-Control Registry of Excimer Laser Coronary Angioplasty Versus Distal Protection Devices in Patients With Acute Coronary Syndromes due to Saphenous Vein Graft Disease

Laser atherectomy might decrease procedural complications during percutaneous coronary intervention (PCI) of degenerated saphenous vein grafts (SVGs) in case of unstable or thrombotic lesions because of its ability to debulk and vaporize thrombus. We aimed at prospectively evaluating the safety and efficacy of excimer laser coronary angioplasty (ELCA) as a primary treatment strategy in consecutively unstable patients undergoing PCI of degenerated SVG lesions. Seventy-one consecutive patients with non-ST elevation acute coronary syndrome (mean age 69 ± 10 years, 66 men [89%]) undergoing PCI of degenerated SVG were enrolled in a prospective case-control registry, using 2 different distal protection devices (DPDs; FilterWire EZ [Boston Scientific, Natick, Massachusetts; n = 24] and SpiderRX [Ev3, Plymouth, Minnesota; n = 23]) or ELCA (n = 24). Primary end points of the study were incidence of angiographic microvascular obstruction (Thrombolysis In Myocardial Infarction flow grade of <3 or Thrombolysis In Myocardial Infraction flow grade of 3 with myocardial blush grade 1 to 2) and incidence of type IVa myocardial infarction. Angiographic microvascular obstruction incidence tended to be less in ELCA-treated patients compared with DPD-treated patients (3 [13%] vs 15 [32%], p = 0.09). Type IVa myocardial infarction incidence was more in DPD-treated patients compared with ELCA-treated patients (23 [49%] vs 5 [21%], p = 0.04). In conclusion, in patients with non-ST elevation acute coronary syndrome undergoing PCI of degenerated SVG, ELCA compared with DPD, is associated with a trend for better myocardial reperfusion and a lesser incidence of periprocedural necrosis. Controlled randomized trials are warranted to confirm these early observations.

Guiding-catheter thrombectomy combined with distal protection during primary percutaneous coronary intervention of a saphenous vein graft

Primary percutaneous intervention of saphenous vein grafts is associated with a high risk of distal embolization and no reflow. We report a case of acute myocardial infarction with a large intragraft thrombus, successfully treated with a technique combining thrombectomy with a 6 Fr guiding catheter and distal protection with the FilterWire EZ.

Abstract 2327: Impact Of MRI Based Carotid Artery Plaque Evaluation On The Risks Of Thromboembolic Events During Carotid Artery Stenting.

Objective: To evaluate if the MRI image findings of carotid arterial plaques using Magnetization-Prepared Rapid Acquisition with Gradient Echo (MPRAGE) is associated with the risk of thromboembolic event during carotid artery stenting (CAS). Methods: A total of 109 carotid stenting was performed on 99 patients. Correlation between the Pre-operative MRI findings of carotid arterial plaque using MPRAGE and the procedure related thromboembolic event was assessed. Distal protection devices were used in all cases including a balloon protection device (Guardwire) and filter devices (AngioguardXP, Filterwire EZ). All lesions were classified into three types according to the intensities on MPRAGE: high intensity (group A), intermediate intensity (group B) and iso-intensity groups (group B). Procedure related morbidity within 30days of procedure was evaluated using Modified Rankin Scale (MRS). Results: Neurological ischemic events associated with the carotid stenting occurred in 11 out of 109 procedures (10.1%). Two (1.8%) cases showed persistent neurological deficit and six (5.5%) showed transient neurological events. Ocular ischemia occurred in 3 cases (2.8%). Thromboembolic events in group A (n=40), group B (n=36) and group C (n=30) were 7 (23.3%), 4 (11.1%) and 0 (0%), respectively. The incidence of thromboembolic events was significantly higher in the combined group A and B as compared to that in group C (P=0.006). Thromboembolic events of CAS with use of Guardwire, Angioguard and Filterwire were 12.1%, 14.3% and 0%, respectively. In CAS for high intensity plaque (n=66), incidence of thromboembolic event with use of Angioguard (4 of 15, 26.7%) was higher than that of Guardwire (7 of 38, 18.4%). In group A, none of the cases (n=20) treated with filter wire showed procedure related ischemic event. Conclusions: High intensity plaque on MPRAGE can be related to high rate of thromboembolic events during CAS.

Carotid artery revascularization with distal protection in high‐surgical‐risk patients in routine clinical practice: Rationale and design of the CABANA safety surveillance program

Continuous improvement in carotid artery stenting (CAS) outcomes, especially for periprocedural death and stroke in high-surgical-risk patients, have been seen in recent randomized trials of CAS versus carotid endarterectomy and CAS registries. However, these studies use stringent inclusion/exclusion criteria for patient, institution, and physician selection. The Carotid Stenting Boston Scientific Surveillance Program (CABANA) study was initiated to evaluate periprocedural outcomes with modern versions of the Carotid Wallstent and FilterWire EZ System for operators with a wide range of clinical specialties, CAS experience and training levels, in patients with a broad range of high-surgical-risk conditions and lesion types. This prospective, single-arm study enrolled 1,097 subjects with 1,098 carotid artery lesions at 99 study centers. Investigators were grouped into one of three tiers according to whether they had a high, medium, or low level of previous CAS experience and were also categorized by their CAS-credential-based training requirements for the CABANA study. Follow-up at 30 days includes clinical evaluation and independent neurological and NIH stroke scale assessments. The primary endpoint rate of 30-day composite stroke, death, and MI, as well as the rates of these individual events, will be evaluated across the overall study, by physician experience tier, and by physician training tier. The evaluation of periprocedural CAS safety in a real-world environment with modern devices in high-surgical-risk patients treated by physicians with a broad range of training and experience will better inform treatment decisions in the future.

ＦｉｌｔｅｒＷｉｒｅ ＥＺを用いたステント留置術中にｎｏ ｆｌｏｗを来した１例：症例報告

【目的】FilterWire EZ（FWEZ）を用いた頚動脈ステント留置術（carotid artery stenting；CAS）中にno flowとなり，脳梗塞を来した１例を報告する．【症例】78歳，男性．右大脳半球に陳旧性脳梗塞を伴う進行性右内頚動脈狭窄に対してCASを施行した後，無症候性ながら進行する左内頚動脈狭窄に対してCASを追加した．FWEZを用いたdistal protectionを行い，ステント留置後に後拡張を行ったところno flowを来した．直後より，意識レベルの低下，失語，右片麻痺を呈し，術後のMRIでは左大脳半球に散在する脳梗塞を認めた．【結論】FWEZは効果的な遠位塞栓予防デバイスであり，従来のフィルタータイプのデバイスより優れていることが報告されているが，本デバイスを用いた場合にも本例のようにno flowを来し，症候性脳梗塞が起こり得ることを認識する必要がある．

Filter no-reflow during percutaneous coronary intervention of saphenous vein grafts: incidence, predictors and effect of the type of protection device

To assess the main predictors and significance of filter no-reflow (FNR) in protected saphenous vein graft (SVG) percutaneous coronary intervention (PCI) and the effect of two different filter-based devices on FNR incidence. The phenomenon of FNR has been described as a transient impairment of blood flow due to debris plugging of a filter-based device used to shield the distal microvasculature during SVG PCI. Fifty consecutive patients treated with SVG PCI were enrolled, using two different filter-based devices (FilterWire EZ™ [Boston Scientific, Natick, MA, USA] and SpiderRX® [Ev3, Plymouth, MN, USA]). We evaluated: 1) the value of clinical and angiographic variables for predicting FNR including the recently-described "degeneration score" (DS); 2) the predictive value of FNR for post-procedural (type IVa) myocardial infarction (MI); 3) the effect of filter type on incidence of FNR. FNR was observed in 30% of patients and was predicted by a higher DS at baseline (2.1±0.9 vs. 1.4±0.8, p=0.02, respectively) as well as by the type of filter used (54% vs. 23% in SpiderFX and FilterWire EZ, respectively, p=0.04). However, at multivariate analysis DS was the only independent predictor of FNR (OR 2.47, CI 95% 1.06-5.76, p=0.04). Graft age and FNR were found to be independent predictors of type IVa MI (OR 1.28; CI%E2%80%AF95% 1.01-1.64, p=0.04 and OR 15.69; CI%E2%80%AF95% 2.12-116.39, p=0.007, respectively). FNR is a common complication of protected SVG stenting. FNR occurs mainly in grafts with a high degeneration score, and the presence of FNR predicts post-procedural myocardial infarction.

Abstract 9848: A Subgroup Analysis of Carotid Artery Stenting with Distal Protection in High Surgical Risk Patients in Routine Clinical Practice: Results of the CABANA Safety Surveillance Program

INTRODUCTION: The multicenter, nonrandomized CABANA Study evaluated periprocedural outcomes in high surgical risk patients with carotid artery stenosis treated with the Carotid WALLSTENT plus FilterWire EZ Embolic Protection System (Boston Scientific, Natick, MA) HYPOTHESIS: We assessed whether a patient's symptomatic status, high risk category and age (≤80 years vs &gt;80 years) had an impact on the 30-day composite rate and individual event rates of major adverse events (MAE including stroke, death and myocardial infarction [MI]). METHODS: Of the 1,097 patients enrolled, 34.4% were at high risk for carotid endarterectomy due to prespecified anatomic criteria, while 65.6% had medical comorbidities. Approximately one-third of patients were symptomatic for carotid artery disease (≥50% carotid artery stenosis); the rest were asymptomatic (≥80% carotid stenosis). Follow-up at 30 days included clinical evaluation and independent neurologic and NIH stroke scale assessments. RESULTS: At 30 days postprocedure, the MAE rate in the overall population was 4.6% (47/1025). In asymptomatic and symptomatic patients, MAE rates were 4.2% (29/697) and 5.5% (18/328); respectively ( P =0.34); in the ≤80-year and &gt;80-year cohort, MAE rates were 4.1% (34/836) and 6.9% (13/189), respectively ( P =0.10). Individual event rates are shown in Table 1. Patients with comorbid risk factors showed strong trends towards higher major stroke rates (2.5% vs 0.9%, P =0.07) versus those at anatomic high risk. No differences were seen in MAE (3.7%, anatomic vs 5.1%, comorbid, P=0.33), death, or MI rates between groups. CONCLUSIONS: Composite MAE and individual event rates at 30 days in all subgroups were low and similar to the outcomes in the overall CABANA dataset. A trend toward higher incidence of major stroke in the comorbid high risk group was observed. These results demonstrate the safety of the Carotid WALLSTENT plus FilterWire EZ in high surgical risk patients, regardless of their risk profile.

Microembolization During Carotid Artery Stenting in Patients With High-Risk, Lipid-Rich Plaque: A Randomized Trial of Proximal Versus Distal Cerebral Protection

The goal of this study was to compare the rate of cerebral microembolization during carotid artery stenting (CAS) with proximal versus distal cerebral protection in patients with high-risk, lipid-rich plaque. Cerebral protection with filters partially reduces the cerebral embolization rate during CAS. Proximal protection has been introduced to further decrease embolization risk. Fifty-three consecutive patients with carotid artery stenosis and lipid-rich plaque were randomized to undergo CAS with proximal protection (MO.MA system, n = 26) or distal protection with a filter (FilterWire EZ, n = 27). Microembolic signals (MES) were assessed by using transcranial Doppler during: 1) lesion wiring; 2) pre-dilation; 3) stent crossing; 4) stent deployment; 5) stent dilation; and 6) device retrieval/deflation. Diffusion-weighted magnetic resonance imaging was conducted before CAS, after 48 h, and after 30 days. Patients in the MO.MA group had higher percentage diameter stenosis (89 ± 6% vs. 86 ± 5%, p = 0.027) and rate of ulcerated plaque (35% vs. 7.4%; p = 0.019). Compared with use of the FilterWire EZ, MO.MA significantly reduced mean MES counts (p < 0.0001) during lesion crossing (mean 18 [interquartile range (IQR): 11 to 30] vs. 2 [IQR: 0 to 4]), stent crossing (23 [IQR: 11 to 34] vs. 0 [IQR: 0 to 1]), stent deployment (30 [IQR: 9 to 35] vs. 0 [IQR: 0 to 1]), stent dilation (16 [IQR: 8 to 30] vs. 0 [IQR: 0 to 1]), and total MES (93 [IQR: 59 to 136] vs. 16 [IQR: 7 to 36]). The number of patients with MES was higher with the FilterWire EZ versus MO.MA in phases 3 to 5 (100% vs. 27%; p < 0.0001). By multivariate analysis, the type of brain protection was the only independent predictor of total MES number. No significant difference was found in the number of patients with new post-CAS embolic lesion in the MO.MA group (2 of 14, 14%) as compared with the FilterWire EZ group (9 of 21, 42.8%). In patients with high-risk, lipid-rich plaque undergoing CAS, MO.MA led to significantly lower microembolization as assessed by using MES counts.

Final Results of the Protected Superficial Femoral Artery Trial Using the Filter Wire EZ System

Conclusion: A distal protection device during femoral popliteal interventions reduces distal migration of debris. Summary: The study evaluated the safety and efficacy of a single distal protection device (Filter Wire EZ Embolic Protection System, Boston Scientific, Mountain View, Calif) for capturing debris during superficial femoral artery (SFA) percutaneous interventions. An additional aim was to define the incidence of distal embolization during SFA interventions. This was a prospective, single-center registry. The study included 30 patients suitable for percutaneous transluminal angioplasty (PTA). Primary end points were occurrence of distal embolization, decreased runoff, improvement in ankle-brachial index (ABI), and number of filters containing emboli. Secondary end points included procedural or device-related death and/or clinical target lesion revascularization, device delivery, deployment success, and incidence of embolic recovery. Procedural success was defined as <30% residual stenosis, with no worsening of distal runoff as determined by angiography. The study enrolled 29 patients with 30 treated limbs, suitable for PTA, between February 2007 and March 2008. Claudication was the indication for intervention in 26 patients and critical limb ischemia in 3. One patient underwent treatment in both legs. The average degree of stenosis was 86% ± 7%, and stenosis length ranged from 8 to 88 mm. No procedural or device-related complications occurred. Average degree of residual stenosis was 10 % ± 10%. ABI improved from 0.56 ± 0.16 to 0.92 ± 0.19 (P < .05). At 1 month, there was no ultrasound-detected waist stenoses or dissections. Microscopic debris was found in 27 of the 30 filters used. Particle size was 1200 ± 640 μm (range, 90-2000 μm). Histologic analysis indicated debris consisted of platelets, erythrocytes, inflammatory cells, extracellular matrix, and cholesterol. There was no correlation between lesion morphology and type of debris. Comment: This is a small, single-center, nonrandomized commercially sponsored study with the first author having a consulting arrangement with the study sponsor. The study is obviously good marketing material for the manufacture of the FilterWire EZ System. However, assuming the author's observations are accurate, the study should bring some measure of concern to all who perform catheter-based SFA interventions, because these interventions seem to be nearly uniformly associated with distal embolization. Long-term clinical implications of these distal emboli remain to be defined, but as someone once said, they may not be bad, but they can't be good! The true clinical utility of embolic protection devices in all vascular beds remains an intriguing, and certainly a potentially profitable, avenue of research.

Initial experience of carotid artery stenting using the Carotid WALLSTENT and FilterWire EZ in Japan

The Carotid WALLSTENT (CWS) and Filter-Wire EZ (FWEZ) embolic protection devices for use in carotid arterial stenting (CAS) were newly approved for national health insurance coverage in Japan in April 2010. This article describes our initial experience of CAS using the CWS and FWEZ. A group of 14 patients (12 men, 2 women; mean age 70.1 years, range 59-83 years) with 15 carotid artery stenoses at high risk for carotid endarterectomy were treated by CAS using the CWS and FWEZ. Of these stenoses, 5 were symptomatic with ≥50% stenosis of the common or internal carotid artery (ICA), and 10 were asymptomatic with ≥80% stenosis. The rates of technical success, ICA flow impairment during filter protection, periprocedural ischemic stroke, 30-day major adverse events (MAEs) (stroke, death, myocardial infarction), and development of new ischemic lesions on diffusion-weighted imaging (DWI) were assessed. CAS was successful in all cases. There was no ICA flow impairment, periprocedural ischemic stroke, or MAEs. DWI showed new ipsilateral ischemic lesions in only one patient (6.7%). Our initial clinical experience using the CWS and FEWZ for CAS was generally excellent, and the incidence of postprocedural ischemic lesions was low.

Final Results of the Protected Superficial Femoral Artery Trial Using the FilterWire EZ System

Final Results of the Protected Superficial Femoral Artery Trial Using the FilterWire EZ System

Computational Modeling of Distal Protection Filters

To quantify the relationship between velocity and pressure gradient in a distal protection filter (DPF) and to determine the feasibility of modeling a DPF as a permeable surface using computational fluid dynamics (CFD). Four DPFs (Spider RX, FilterWire EZ, RX Accunet, and Emboshield) were deployed in a single tube representing the internal carotid artery (ICA) in an in vitro flow apparatus. Steady flow of a blood-like solution was circulated with a peristaltic pump and compliance chamber. The flow rate through each DPF was measured at physiological pressure gradients, and permeability was calculated using Darcy's equation. Two computational models representing the RX Accunet were created: an actual representation of the filter geometry and a circular permeable surface. The permeability of RX Accunet was assigned to the surface, and CFD simulations were conducted with both models using experimentally derived boundary conditions. Spider RX had the largest permeability while RX Accunet was the least permeable filter. CFD modeling of RX Accunet and the permeable surface resulted in excellent agreement with the experimental measurements of velocity and pressure gradient. However, the permeable surface model did not accurately reproduce local flow patterns near the DPF deployment site. CFD can be used to model DPFs, yielding global flow parameters measured with bench-top experiments. CFD models of the detailed DPF geometry could be used for "virtual testing" of device designs under simulated flow conditions, which would have potential benefits in decreasing the number of design iterations leading up to in vivo testing.

Final Results of the Protected Superficial Femoral Artery Trial Using the FilterWire EZ System

The purpose of this study was to evaluate the safety and efficacy of debris-capture for distal protection using the FilterWire EZ Embolic Protection System (Boston Scientific, Mountain View, CA) with the additional aim to further define the incidence of distal embolization during superficial femoral artery (SFA) interventions. A prospective, single-centre registry was designed to evaluate the performance of the FilterWire EZ in capturing debris during standard SFA percutaneous intervention. The PRO-RATA study included 30 patients suitable for PTA (Fontaine IIb to III or Rutherford I to II classification). The primary end points were occurrence of distal embolization or decreased runoff, improvement in ankle-brachial index ankle-brachial index (ABI) after the procedure, and number of filters containing emboli. Secondary end points included major adverse events (i.e., procedure- or device-related death and/or clinical target lesion revascularisation), device delivery, deployment success, and incidence of embolic recovery (patients with device success exhibiting embolic protection in the filter). Procedural success was determined as ≤30% residual stenosis with no worsening of distal runoff as determined on angiography. A total of 29 patients (age 66.2 ± 12 years; total no. of limbs = 30; total no. of lesions = 30) suitable for PTA were enrolled in the study between February 2007 and March 2008. There were 26 patients with claudication (Fontaine IIB) and 3 patients with stage IV peripheral vascular disease. In one patient, lesions in both legs were treated. No procedural or device-related complications occurred. The average degree of stenosis was 86 ± 7%. Stenosis length ranged from 8 to 88 mm. The average degree of residual stenosis was 10 ± 10%. ABI improved from 0.56 ± 0.16 to 0.92 ± 0.19 (P < 0.05). No restenosis or dissection was seen at 1-month ultrasound follow-up. Macroscopic debris was found in 27 of 30 filters of all distal protection devices used in all 29 patients. Debris particle size ranged from 90 to 2000 μm (1200 ± 640). Histological debris analysis showed platelets, erythrocytes, inflammatory cells, extracellular matrix, and cholesterol as being the major components of emboli. Additional immunochemistry showed no correlation between lesion morphology and debris components. The FilterWire EZ is easy and safe to handle. The system caused no complications. In all cases, macroscopic debris was captured. Using a distal protection device during femoropopliteal interventions has the potential to prevent migration of debris, which may be important for high-risk patients with limited distal runoff.

In Vitro Performance Assessment of Distal Protection Filters: Pulsatile Flow Conditions

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. 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. 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%). 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.

The Effect of Tortuosity on Five Different Cerebral Protection Devices in an Ex-vivo Model

To compare the efficacy and ease of deployment for five currently available cerebral protection devices at varying degrees of tortuosity. An ex-vivo study using procured canine carotid arteries was performed using an open flow model with three anatomical variants (non-tortuous, mildly tortuous, and severely tortuous) and two embolic particle sizes (250 and 425 microns). Cerebral protection devices (Accunet [Guidant Corporation, Santa Clara, Calif], Angioguard [Cordis, Miami Lakes, Fla], Emboshield [Abbott Laboratories, Abbott Park, III], Filterwire EZ [Boston Scientific Corporation, Natick, Mass], and SpideRX [ev3, Inc, Plymouth, Minn]) were placed under fluoroscopy at the point of maximal inflection in the case of tortuous vessels. A total of 1.5 mg (± 0.05 mg) of polyvinyl alcohol (PVA) particles of either size was injected into the carotid system proximal to each of five protection devices at each of the three degrees of tortuosity. Particles captured by the filters were weighted and compared with the weight of the particles collected in the effluent filter (not captured). The time taken to deploy each device at this position was recorded. The percent capture for each of the five filters at each degree of tortuosity using 425 micron particles is shown in the Fig. Similar results were obtained for the 250 micron particles. Filterwire EZ and SpiderX were deployed within the 26 to 27 second range. All others were deployed between 30 and 36 seconds. No filter completely prevented embolization. Filterwire EZ, Accunet, and Angioguard exhibited the highest capture rates in straight anatomy. Angioguard was the most efficacious filter in tortuous anatomy. Increasing tortuosity had a significant negative impact on all filters. Filterwire EZ and SpiderX had the best trackability in tortuous vessels using this model.

Prison break: getting a distal protection device out of jail

A man in his late 60s presented with worsening angina, 8 years after successful coronary artery bypass surgery. Cardiac catheterisation revealed a high-grade stenosis in a saphenous vein graft to...

Implantace stentů do významných stenóz karotických tepen s použitím protektivního systému FilterWire EZ&lt;sup&gt;TM&lt;/sup&gt;

Implantace stentů do významných stenóz karotických tepen s použitím protektivního systému FilterWire EZ&lt;sup&gt;TM&lt;/sup&gt;

Feasibility, safety, and early outcomes of direct carotid artery stent implantation with use of the FilterWire EZ™ Embolic Protection System

To report on early outcomes of prospective single-center registry, which evaluated feasibility, safety, and effectiveness of direct carotid stenting using FilterWire EZ Embolic Protection System in high-risk patients. Little is known about the use of direct carotid stenting with FilterWire EZ Embolic Protection System and different carotid stents. Between September 2005 and August 2008, 176 consecutive patients (70 +/- 9 years, 36% symptomatic, 89% at high risk) underwent 214 direct carotid artery stenting procedures with FilterWire EZ Embolic Protection System and different carotid stents. This study included both symptomatic (>or=50% carotid artery stenosis) as well as asymptomatic (>or=70% carotid artery stenosis) patients. The primary endpoint was the rate of 30-day adverse events, defined as neurological death, stroke, or myocardial infarction. We implanted 218 stents (55% with closed cell design) in 214 procedures. The technical success rate of direct stenting was 96%. Carotid artery stenosis before and after direct carotid artery stenting were 82% +/- 10% and 10% +/- 13%, respectively. The median of fluoroscopic time was 6 min (range 2.5-31.5 min). There were two (0.9%) minor strokes and one (0.5%) myocardial infarction within 30 post-procedural days; the primary endpoint occurred in three patients (1.4%). Two patients expired from nonneurological causes unrelated to carotid stenting. Direct carotid stenting with FilterWire EZ Embolic Protection System is feasible and safe. Short-term results with respect to neurological events are acceptable.

Feasibility of simultaneous pre- and postfilter transcranial Doppler monitoring during carotid artery stenting

Carotid artery stenting (CAS) is emerging as an acceptable treatment alternative to surgery for patients with carotid artery stenosis. The major risk of CAS is cerebral embolization of plaque and thrombus causing stroke or asymptomatic brain infarction. Use of embolic protection devices (EPD) to trap emboli before they reach the brain is now standard practice in CAS. The pore size of the currently available filters is >100 microns and emboli smaller than the EPD pores can still reach the brain. While the use of EPD is widespread, little evidence exists of their in vivo efficacy in preventing distal embolization. Our aim was to quantify the number of emboli reaching the brain with the device in place. Therefore, the expected value of this report is in its description of a novel application of transcranial Doppler (TCD). Due to the limited number of cases, it is not intended to support the use of one EPD over another. Six patients were monitored with ipsilateral simultaneous dual probe TCD during CAS. Two types of cerebral protection systems were evaluated: FilterWire EZ System (FW; Boston Scientific, Santa Clara, Calif) and GORE Neuro Protection System (NPS; W.L. Gore and Associates, Flagstaff, Ariz). By placing TCD probes both proximal and distal to the filterwire EPD, we quantified the microembolic signals before the EPD as well as those, which reached the intracranial circulation after the EPD. One probe was placed submandibularly to monitor the ICA (SICA), while another was placed transtemporally to monitor the middle and anterior cerebral artery (MCA + ACA). We compare the number of extracranial emboli prior to the EPD with the number of intracranial emboli after the EPD. Dual probe monitoring was successful during the five stages of the CAS: lesion crossing (LC), predilatation (PreD), stent placement (SP), postdilatation (PostD), and filter/device removal (FR/DR). Using FW during LC by probe 1 (SICA)/probe 2 (MCA + ACA): (18 [range, 15-22]/15 [range, 11-20]), PreD (111 [range, 101-121]/101 [range, 90-111]), SP (68 [range, 60-76]/42 [range, 30-53]), PostD (27 [range, 25-30]/24 [range, 22-27]), FR (0.3 [range, 0-1]/0.7 [range, 0-1]) average number of microembolic signals were detected. Using NPS during LC (1.7 [range, 0-3]/1 [range, 0-2]), PreD (0/1.7 [range, 0-4]), SP (0/0), PostD (0/0), DR (18 [range, 0-18]/6.7 [range, 1-13]) average number of microembolic signals were detected. EPD significantly reduces but does not eliminate the number of microemboli reaching the brain during carotid artery angioplasty and stenting. We propose monitoring of CAS with submandibular and transtemporal TCD probes to further evaluate the practice of distal embolization protection. Although our study is not powered to make any recommendations about EPDs, we believe that sequential dual probe TCD monitoring is a worthy tool with the potential to give vital information to assess the various devices and the techniques of utilization.

Embolic Protection Devices in Patients with Renal Artery Stenosis with Chronic Renal Insufficiency: A Clinical Study

To present clinical outcomes with the use of embolic protection devices (EPDs) and renal artery stents in patients with chronic renal insufficiency (CRI) and renal artery stenosis (RAS). A retrospective study was conducted in 23 patients with RAS and CRI who were treated with renal artery stent placement with an EPD. Follow-up data were obtained through medical records. In 23 patients (18 men; 78%) with an average age of 69.4 years +/- 11 (range, 46-86 y), 32 renal arteries were treated for worsening renal function (n = 17; 74%) or uncontrolled hypertension and worsening renal function (n = 6; 26%). Nine FilterWire EZ devices were used in eight patients (35%) and 17 SpideRX devices were used in 15 patients (65%). The average follow-up was 8 months +/- 5. After the stent procedure, the mean systolic blood pressure decreased significantly (P < .05) whereas the diastolic pressure remained unchanged. There was a significant increase in the mean estimated glomerular filtration rate from 32.9 mL/min +/- 12.9 at baseline to 41.3 mL/min +/- 13.7 at last follow-up (P < .05). In 96% of patients, there was improvement or stabilization of kidney function. In six of the 17 SpideRX devices (35%), macroscopically evident embolic material was observed in the device after stent placement. There were two minor and two major complications. Renal artery stent placement combined with the use of a SpideRX or FilterWire EZ device is associated with an good clinical outcome with a reasonable safety profile.