Cerebral protection with filter devices during carotid artery stenting

Outcome of CAS under flow reversal and analysis for the intraprocedural flow of internal carotid artery

OBJECTIVE

Carotid artery stenting (CAS) under flow reversal with dual protection using a proximal balloon and distal filter has been an established procedure for internal carotid artery (ICA) stenosis. This study investigates the effect of external carotid artery (ECA) occlusion on outcomes of CAS and ICA flow under flow reversal.

METHODS

We reviewed 231 cases of CAS under flow reversal with ECA occlusion and 32 without. In the last 14 of 32 cases, the flow in the ICA under flow reversal was analyzed by ultrasound. The collateral index, which was defined as the total value of the maximum diameters of the ipsilateral anterior cerebral artery at the A1 segment and the anterior communicating artery, as well as those of the ipsilateral posterior cerebral artery at the P1 segment and the ipsilateral posterior communicating artery, and the maximum diameter of the ipsilateral ECA were correlated with the flow direction in the ICA.

RESULTS

There was no significant difference in the outcome of CAS between the groups with or without ECA occlusion. Among the 14 cases without ECA occlusion, antegrade flow in the ICA was observed in 6 cases (42.9 %). The group with the antegrade flow in the ICA exhibited a significantly lower collateral index (5.08±0.33 vs 6.71±0.28, p=0.01) and a significantly larger ECA diameter (4.66±0.51 mm vs 3.21±1.24 mm, p=0.01) than the group with the stagnant or retrograde flow in the ICA.

CONCLUSIONS

The outcomes of CAS under flow reversal were acceptable even without ECA occlusion. The ECA occlusion may not be necessary for CAS under dual protection; however, distal filter protection should be used even under flow reversal.

Randomized Controlled Trial of Conventional Versus MicroNet-Covered Stent in Carotid Artery Revascularization

OBJECTIVES

The aim of this study was to compare procedure-related ipsilateral cerebral embolism with a conventional (Acculink, Abbott Vascular) versus a MicroNet-covered (CGuard, InspireMD) stent in carotid artery stenting (CAS).

BACKGROUND

The MicroNet-covered stent may reduce periprocedural cerebral embolism in CAS, but level 1 evidence is lacking.

METHODS

A total of 100 consecutive patients were randomized 1:1 to filter-protected CAS using the Acculink or the CGuard device. The study was powered for its primary endpoint of at least 50% reduction in ipsilateral diffusion-weighted magnetic resonance imaging lesion average volume 48 hours postprocedure (blinded external core laboratory analysis).

RESULTS

The baseline characteristics of the study groups were similar. Eighty-two (total volume = 18,212 mm³) diffusion-weighted magnetic resonance imaging postprocedural cerebral lesions occurred in 26 Acculink-treated patients and 45 lesions (total volume = 3,930 mm³; 78.4% reduction) in 25 CGuard-treated patients. New cerebral lesion average volume was 171 mm³ vs 73 mm³ (P = 0.017) per affected patient and 222 mm³ vs 84 mm³ (P = 0.038) per lesion (Acculink vs CGuard). In lesion-affected patients, the average sum of lesion volumes was 701 mm³ vs 157 mm³ (P = 0.007). The Acculink significantly increased the risk for multiple (≥5) cerebral lesions (relative risk: 7.8; 95% CI: 1.3-14.9; P = 0.021). At 30 days, new permanent (fluid-attenuated inversion recovery) lesion prevalence was 3:1 (P < 0.001), with total permanent lesion volume 7,474 mm³ vs 574 mm³ (92.3% reduction with the CGuard). There were 6 vs 0 new ipsilateral lesions (P = 0.030) and 2 versus 0 strokes.

CONCLUSIONS

The MicroNet-covered stent significantly reduced periprocedural and abolished postprocedural cerebral embolism in relation to a conventional carotid stent. This is consistent with the MicroNet-covered stent's sustained embolism prevention, translating into cerebral protection not only during but also after CAS. The present findings may influence decision making in carotid revascularization. (The SIBERIA Trial [Acculink™ Versus CGuard™]; NCT03488199).

Effects of a dual-filter-based cerebral embolic protection device in transcatheter aortic valve replacement on cerebral oxygen saturation: A prospective pilot study

PURPOSE

The Sentinel Cerebral Protection System (Sentinel-CPS) is increasingly used in transcatheter aortic valve replacement (TAVR). However, the impact of inserting the Sentinel-CPS inside the brain-supplying arteries on cerebral perfusion and oxygenation is unknown.

METHODS

Twenty patients undergoing transfemoral TAVR with (n = 10) and without (n = 10) cerebral embolic protection using the Sentinel-CPS were prospectively observed. All patients received conscious sedation and cerebral oxygen saturation (rSO₂ ) was continuously measured with near-infrared spectroscopy (NIRS). The cumulative perioperative cerebral desaturation was calculated for each patient by multiplying rSO₂ below an individualized desaturation threshold by time. In addition, rSO₂ values at the time of Sentinel-CPS insertion, filter positioning, and device retraction were analyzed.

RESULTS

There was no significant difference in cumulative cerebral desaturation in patients with Sentinel-CPS (median [IQR]) (0 [0/81] s%) and without (median [IQR]) (0 [0/23] s%), p = .762. A total of 6 patients (33.3%) experienced a perioperative decrease in rSO₂ below the individualized desaturation threshold (n = 3 with Sentinel-CPS, n = 3 without Sentinel-CPS; p = 1.000). Cerebral desaturation was detected during valve deployment (n = 5) and after postdilatation (n = 1). No desaturation events occurred during Sentinel-CPS insertion, filter positioning, or retraction.

CONCLUSION

Our pilot study revealed no difference in cumulative perioperative cerebral desaturation between TAVR with and without Sentinel-CPS. Catheter- and filter-based manipulations in the brain-supplying arteries for Sentinel-CPS application were not associated with a decrease of cerebral perfusion and oxygenation.

Carotid artery stenting versus endarterectomy for treatment of carotid artery stenosis

BACKGROUND

Carotid artery stenting is an alternative to carotid endarterectomy for the treatment of atherosclerotic carotid artery stenosis. This review updates a previous version first published in 1997 and subsequently updated in 2004, 2007, and 2012.

OBJECTIVES

To assess the benefits and risks of stenting compared with endarterectomy in people with symptomatic or asymptomatic carotid stenosis.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (last searched August 2018) and the following databases: CENTRAL, MEDLINE, Embase, and Science Citation Index to August 2018. We also searched ongoing trials registers (August 2018) and reference lists, and contacted researchers in the field.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing stenting with endarterectomy for symptomatic or asymptomatic atherosclerotic carotid stenosis. In addition, we included RCTs comparing carotid artery stenting with medical therapy alone.

DATA COLLECTION AND ANALYSIS

One review author selected trials for inclusion, assessed trial quality and risk of bias, and extracted data. A second review author independently validated trial selection and a third review author independently validated data extraction. We calculated treatment effects as odds ratios (OR) and 95% confidence intervals (CI), with endarterectomy as the reference group. We quantified heterogeneity using the I² statistic and used GRADE to assess the overall certainty of evidence.

MAIN RESULTS

We included 22 trials involving 9753 participants. In participants with symptomatic carotid stenosis, compared with endarterectomy stenting was associated with a higher risk of periprocedural death or stroke (the primary safety outcome; OR 1.70, 95% CI 1.31 to 2.19; P < 0.0001, I² = 5%; 10 trials, 5396 participants; high-certainty evidence); and periprocedural death, stroke, or myocardial infarction (OR 1.43, 95% CI 1.14 to 1.80; P = 0.002, I² = 0%; 6 trials, 4861 participants; high-certainty evidence). The OR for the primary safety outcome was 1.11 (95% CI 0.74 to 1.64) in participants under 70 years old and 2.23 (95% CI 1.61 to 3.08) in participants 70 years old or more (interaction P = 0.007). There was a non-significant increase in periprocedural death or major or disabling stroke with stenting (OR 1.36, 95% CI 0.97 to 1.91; P = 0.08, I² = 0%; 7 trials, 4983 participants; high-certainty evidence). Compared with endarterectomy, stenting was associated with lower risks of myocardial infarction (OR 0.47, 95% CI 0.24 to 0.94; P = 0.03, I² = 0%), cranial nerve palsy (OR 0.09, 95% CI 0.06 to 0.16; P < 0.00001, I² = 0%), and access site haematoma (OR 0.32, 95% CI 0.15 to 0.68; P = 0.003, I² = 27%). The combination of periprocedural death or stroke or ipsilateral stroke during follow-up (the primary combined safety and efficacy outcome) favoured endarterectomy (OR 1.51, 95% CI 1.24 to 1.85; P < 0.0001, I² = 0%; 8 trials, 5080 participants; high-certainty evidence). The rate of ipsilateral stroke after the periprocedural period did not differ between treatments (OR 1.05, 95% CI 0.75 to 1.47; P = 0.77, I² = 0%). In participants with asymptomatic carotid stenosis, there was a non-significant increase in periprocedural death or stroke with stenting compared with endarterectomy (OR 1.72, 95% CI 1.00 to 2.97; P = 0.05, I² = 0%; 7 trials, 3378 participants; moderate-certainty evidence). The risk of periprocedural death or stroke or ipsilateral stroke during follow-up did not differ significantly between treatments (OR 1.27, 95% CI 0.87 to 1.84; P = 0.22, I² = 0%; 6 trials, 3315 participants; moderate-certainty evidence). Moderate or higher carotid artery restenosis (50% or greater) or occlusion during follow-up was more common after stenting (OR 2.00, 95% CI 1.12 to 3.60; P = 0.02, I² = 44%), but the difference in risk of severe restenosis was not significant (70% or greater; OR 1.26, 95% CI 0.79 to 2.00; P = 0.33, I² = 58%; low-certainty evidence).

AUTHORS' CONCLUSIONS

Stenting for symptomatic carotid stenosis is associated with a higher risk of periprocedural stroke or death than endarterectomy. This extra risk is mostly attributed to an increase in minor, non-disabling strokes occurring in people older than 70 years. Beyond the periprocedural period, carotid stenting is as effective in preventing recurrent stroke as endarterectomy. However, combining procedural safety and long-term efficacy in preventing recurrent stroke still favours endarterectomy. In people with asymptomatic carotid stenosis, there may be a small increase in the risk of periprocedural stroke or death with stenting compared with endarterectomy. However, CIs of treatment effects were wide and further data from randomised trials in people with asymptomatic stenosis are needed.

Dislocation of a cerebral protection device component during carotid stenting: A case report of favorable outcome from conservative management after failure of retrieval

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Though effective, CPDs may cause complications resulting in serious outcomes.

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No unique solution (conservative/surgical) for risk-free management of entrapment.

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Improving standard of care and patient safety is a top priority.

Introduction

Cerebral-protection devices (CPDs) are a well-established system for reduction of embolic risk in carotid artery angioplasty and stenting (CAS). Although rare, adverse events with CPDs are unpredictable and can be associated with serious outcomes and iatrogenic sequelae.

Presentation of case

We describe the unique case of dislocation of a FilterWire EX™ filter loop during right CAS. On trying to recapture the CPD filter at the end of the procedure, the filter loop suddenly detached from the guidewire and dislocated to the proximal middle cerebral artery. Attempted retrieval of the loop failed and the patient developed a transient neurological deficit caused by an acute ischemic infarction in the lenticular nucleus. No further retrieval attempt was pursued. No further dislocation of the loop or clinical event have been reported during the 16-year follow up.

Discussion

This case reported a favorable outcome of conservative management for entrapped material from a CPD after iatrogenic damage from failed retrieval. No similar reports are available in the literature, and conservative management is generally not a recommended approach because of the potential complications. However, rescue retrieval attempts are as well a potential source of serious events, and no clear guidelines exist on the management of mechanical complications from CPD.

Conclusion

Entrapment of CPD components constitutes an adverse event with no unique solution for risk-free management. The potential risks associated with the use of protection devices are still to be fully explored, and improving the standard of care and patient safety needs to be a top priority.

Comparison of closed-cell and hybrid-cell stent designs in carotid artery stenting: clinical and procedural outcomes

Introduction

Carotid artery stenting (CAS) is a promising alternative to surgery in high-risk patients. However, the impact of stent cell design on outcomes in CAS is a matter of continued debate.

Aim

To compare the periprocedural and clinical outcomes of different stent designs for CAS with distal protection devices.

Material and methods

All CAS procedures with both closed- and hybrid-cell stents performed at our institution between February 2010 and December 2015 were analyzed retrospectively. Adverse events were defined as death, major stroke, minor stroke, transient ischemic attack and myocardial infarction. Periprocedural and 30-day adverse events and internal carotid artery (ICA) vasospasm rates were compared between the closed-cell and hybrid-cell stent groups.

Results

The study included 234 patients comprising 146 patients with a closed-cell stent (Xact stent, Abbott Vascular) (mean age: 68.5 ±8.6; 67.1% male) and 88 patients with a hybrid-cell stent (Cristallo Ideale, Medtronic) (mean age: 67.2 ±12.8; 68.2% male). There was no significant difference between the groups with respect to periprocedural or 30-day adverse event rates. While there was no difference in terms of tortuosity index between the groups, there was a higher procedural ICA vasospasm rate in the closed-cell stent group (35 patients, 23%) compared with the hybrid-cell stent group (10 patients, 11%) (p = 0.017).

Conclusions

The results of this study showed no significant difference in the clinical adverse event rates after CAS between the closed-cell stent group and the hybrid-cell stent group. However, procedural ICA vasospasm was more common in the closed-cell stent group.

Carotid Stenting for Radiation-Induced Extracranial Carotid Artery Occlusive Disease: Efficacy and Midterm Outcomes

Purpose:

To investigate the immediate and midterm results of carotid stenting for severe radiation-induced extracranial carotid artery disease.

Methods:

Between April 1998 and May 2002, 16 patients (15 men; mean age 64±8 years, range 48–72) presented with 18 severe radiation-induced carotid stenoses in the internal carotid artery (n=3), common carotid artery (n=7), and both vessels (n=8). Thirteen (76%) patients were symptomatic; the mean degree of carotid stenosis was 85%±10% (range 70%–95%). An independent neurological specialist assessed perioperative neurological complications before and after treatment. The patients were followed prospectively for at least 12 months by clinical examination and serial duplex ultrasound scanning. Restenosis was defined as a diameter reduction >50%.

Results:

Of 18 stent procedures attempted (2 staged), 1 was abandoned owing to failure to pass the guidewire across a tight lesion (94% technical success by intent to treat). In the 17 successfully completed procedures, 17 Wallstents and 4 SMART stents were deployed with satisfactory anatomical results. One postoperative stroke occurred as a result of thromboembolism to the ipsilateral middle cerebral artery and led to hospital death (5.9% combined stroke and death rate). One transient ischemic attack occurred (11.6% neurological event rate). With a median 30-month follow-up (range 5–55), 3 (17.6%) recurrent stenoses (>50%) were detected on duplex scan; 1 repeat angioplasty was performed. No new neurological event has been detected.

Conclusions:

Carotid stenting may be performed in patients with irradiation-induced carotid stenosis with acceptable risks and midterm durability.

Secondary Prevention of Ischemic Cerebrovascular Disease. What Is the Evidence?

Patients who had a transient ischemic attack or stroke are at increased risk of experiencing recurrent cerebrovascular events. For this reason, secondary prevention of ischemic cerebrovascular disease is essential. Several modifiable, lifestyle-associated risk factors have been implicated, such as physical activity, smoking, and alcohol consumption. Established and emerging vascular risk factors are associated with an increased risk of stroke. Pharmacologic treatment, including the use of antiplatelet, antihypertensive, and lipid-lowering agents, has also been shown to reduce the risk of secondary cerebrovascular events. Surgical intervention, either open or endovascular, may be the preferred therapeutic option in well-defined subsets of patients. It is important to establish specific measures for the early detection and prevention of recurrent cerebrovascular disease. Therefore, further research and greater awareness in this field are needed.

Atheromatous embolization

Atheromatous embolization is a multisystem disease complicating advanced atherosclerosis. It occurs most often as a complication of angiography, an endovascular procedure or cardiovascular surgery. Atheromatous embolization can present in a subtle manner where it is often under-recognized, or with catastrophic results including myocardial infarction, strake or acute renal failure. It may mimic other disease processes and often goes underdiagnosed and undertreated. A high clinical suspicion is the key to diagnosis. Atheromatous embolization results in significant morbidity and mortality; therefore, early recognition followed by aggressive management may help to prevent end-organ damage and improve overall clinical outcomes. Management strategies should include risk factor modification, prevention of further insults by discontinuing or avoiding predisposing factors, supportive treatment and interventional or surgical approaches to remove the atheroembolic source. Atheromatous embolization is expected to increase as our population ages and the epidemics of diabetes mellitus and obesity increase.

Carotid Revascularization Using Endarterectomy or Stenting Systems (CARESS): Phase I Clinical Trial

Purpose:

To determine whether carotid stenting with embolic protection is equivalent to carotid endarterectomy (CEA) in a broad risk population of patients with symptomatic and asymptomatic carotid stenosis.

Methods:

A prospective, multicenter Phase I trial was conducted comparing standard CEA to carotid stenting systems (CSS) in patients with symptomatic (≥50%) and asymptomatic (≥75%) carotid stenosis. Patients were enrolled using selection criteria reflective of broad clinical practice. The enrollment ratio at each clinical site was designed to be 2:1 (CEA to CSS) to achieve a planned enrollment of 450 patients: 300 in the CEA arm and 150 in the CSS cohort, which would ensure adequate precision with a coefficient of variation ≤0.35. The primary endpoint for comparison was 30-day all-cause mortality and nonfatal stroke.

Results:

Between April 2001 and December 2002, 14 clinical sites enrolled 439 patients, of which 397 (247 men; mean age 71 years, range 44–89) were treated: 254 with CEA and 143 patients with CSS (ratio 1.8 to 1.0). More than 90% of patients had >75% stenosis; ∼68% of patients were asymptomatic. There were no significant differences in baseline patient characteristics between the treatment groups with the exception of a more frequent history of prior CEA (30% CSS versus 11% for CEA, p<0.0001) and prior carotid stent placement in the CSS group (6% versus 0% for CEA, p = 0.0002). There was no significant difference in the 30-day combined all-cause mortality and stroke rate by Kaplan-Meier estimate between CEA (2%) and CSS (2%). There was no significant difference in the secondary endpoint of combined 30-day all-cause mortality, stroke, and myocardial infarction between CEA (3%) and CSS (2%).

Conclusions:

This study suggests that the 30-day risk of stroke or death following carotid stenting with cerebral protection is equivalent to standard carotid endarterectomy in a broad risk population of patients with carotid stenosis.

Medical and Surgical Management of Symptomatic Carotid Stenosis

Carotid bifurcation stenosis is an important cause of ischaemic stroke, particularly in patients with recent transient ischaemic attack or minor stroke. Large randomized trials of endarterectomy have shown that surgery reduces the risk of stroke in patients with ≥ 50% recently symptomatic carotid stenosis, and more recent research has gone some way to wards identifying which patients benefit the most. Individual risk modelling has been shown to be useful in selecting patients with the most to gain from endarterectomy for symptomatic stenosis, although timely surgery and optimal medical treatment are of equal importance.

Comparison of Flow Impairment during Carotid Artery Stenting Using Two Types of Eccentric Filter Embolic Protection Devices

We investigated the angiographic findings and the clinical outcomes after carotid artery stenting (CAS) using two different, eccentric filter embolic protection devices (EPDs). Between July 2010 and August 2015, 175 CAS procedures were performed using a self-expandable closed-cell stent and a simple eccentric filter EPD (FilterWire EZ in 86 and Spider FX in 89 procedures). The angiographic findings (i.e., flow impairment and vasospasm) at the level of EPDs, neurologic events, and post-operative imaging results were compared between the FilterWire EZ and the Spider FX groups. The CAS was angiographically successful in all 175 procedures. However, the angiographs were obtained immediately after CAS-detected flow impairment in the distal internal carotid artery (ICA) in 11 (6.3%) and ICA spasms at the level of the EPD in 40 cases (22.9%). The incidence of these complications was higher with FilterWire EZ than Spider FX (ICA flow impairment of 10.5% vs. 2.2%, P = 0.03; vasospasm 30.2% vs. 15.7%, P = 0.03). There were nine neurologic events (5.1%); five patients were presented with transient ischemic attacks, three had minor strokes, and one had a major stroke. New MRI lesions were seen in 25 (29.1%) FilterWire-group and in 36 (40.4%) Spider-group patients. The neurologic events and new MRI lesions were not associated with the type of EPD used. Although the ICA flow impairment may result in neurologic events, there was no significant association between the FilterWire EZ and the Spider FX CAS with respect to the incidence of neurologic events by the prompt treatment such as catheter aspiration.

Meta-analysis of the Effect of Stent Design on 30-Day Outcome After Carotid Artery Stenting

Purpose: To review the contemporary literature and analyze whether stent cell design plays a role in 30-day outcomes after carotid artery stenting (CAS). Methods: A systematic review of the literature was undertaken that identified 9 studies comparing the effect of different cell design on 30-day outcome in patients undergoing CAS. Random-effects models were applied to calculate pooled outcome data for mortality and cerebrovascular morbidity. Results are reported as the odds ratio (OR) and 95% confidence interval (CI). Results: The 9 studies included 8018 patients who underwent 8028 CAS procedures (4018 open-cell stents, 4010 closed-cell stents). Six studies were retrospective in design, one was a registry, and only two studies prospectively compared the effect of different cell designs. Nearly half of the patients (3452, 43.1%) were symptomatic, with no significant difference between the closed- and open-cell stent groups (p=0.93). During the first month after the procedure, there were no significant differences in mortality (OR 0.69, 95% CI 0.39 to 1.24, p=0.21), transient ischemic attacks (OR 0.95, 95% CI 0.69 to 1.30, p=0.74), or strokes (OR 1.17, 95% CI 0.83 to 1.66, p=0.37). Conclusion: This meta-analysis showed that 30-day cerebrovascular complications after CAS were not significantly different for the open-cell group in comparison to the closed-cell group. Future prospective clinical trials comparing different free cell areas and other stent design properties are still needed to further investigate whether stent design plays a significant role in the results of carotid stenting.

Lesion-Related Carotid Angioplasty and Stenting with Closed-Cell Design without Embolic Protection Devices in High-Risk Elderly Patients-Can This Concept Work Out? A Single Center Experience Focusing on Stent Design

To compare the performance differences of three carotid artery stents in high-risk elderly patients without embolic protection devices (EPDs) on the basis of stent design, procedure-related complications, conveniences in handling, in-stent restenosis, 30-day outcome, and long-term follow-up. A total of 101 symptomatic internal carotid stenoses of 94 patients were prospectively treated with stent-protected angioplasty to 94 patients. Three closed-cell stents, one of those being hybrid cell design, were chosen depending on vascular anatomy: curved vessel, lesion length > 1 cm: 64 Carotid Wallstent (Boston Scientific, Natick, MA); curved vessel, lesion length < 1 cm: 21 Cristallo Ideale (Invatec, Roncadelle, Italy); straight vessel, lesion length > 1 cm: 16 Xact (Vascular Abbott, Santa Clara, CA). Comparisons of demographics, procedures, and outcomes were performed. The mean age of patients was 73.1 years (standard deviation [SD], ± 7.9; range, 58-87 years), 71% of the patients were older than 70 years and 20% were octogenarians. Male/female ratio was 3.1:1. About 13.9% (14/101) had contralateral internal carotid artery occlusion. Overall peri-interventional complication rate was 2.9% and 30-day mortality rate was 1%. During the long-term follow-up (34 months, range 1-59) no ipsilateral stroke was documented. Ten deaths (three after MI) were recognized. Two in-stent restenosis were detected (> 70% North American Symptomatic Carotid Endarterectomy Trial) during follow-up, one patient was detected with previous carotid endarterectomy. Especially, if individual anatomical variance is considered, lesion-related stent-protected carotid angioplasty with lesion-adapted closed-cell design is an effective, reliable, safe, and comprehensible treatment option in symptomatic patients. Even without EPDs, the rate of complications is low, when compared with symptomatic carotid artery stenosis described in the literature. In-stent restenosis seems to play no significant role in follow-up.

Carotid artery stenting: current and emerging options

Carotid artery stenting technologies are rapidly evolving. Options for endovascular surgeons and interventionists who treat occlusive carotid disease continue to expand. We here present an update and overview of carotid stenting devices. Evidence supporting carotid stenting includes randomized controlled trials that compare endovascular stenting to open surgical endarterectomy. Carotid technologies addressed include the carotid stents themselves as well as adjunct neuroprotective devices. Aspects of stent technology include bare-metal versus covered stents, stent tapering, and free-cell area. Drug-eluting and cutting balloon indications are described. Embolization protection options and new direct carotid access strategies are reviewed. Adjunct technologies, such as intravascular ultrasound imaging and risk stratification algorithms, are discussed. Bare-metal and covered stents provide unique advantages and disadvantages. Stent tapering may allow for a more fitted contour to the caliber decrement between the common carotid and internal carotid arteries but also introduces new technical challenges. Studies regarding free-cell area are conflicting with respect to benefits and associated risk; clinical relevance of associated adverse effects associated with either type is unclear. Embolization protection strategies include distal filter protection and flow reversal. Though flow reversal was initially met with some skepticism, it has gained wider acceptance and may provide the advantage of not crossing the carotid lesion before protection is established. New direct carotid access techniques address difficult anatomy and incorporate sophisticated flow-reversal embolization protection techniques. Carotid stenting is a new and exciting field with rapidly advancing technologies. Embolization protection, low-risk deployment, and lesion assessment and stratification are active areas of research. Ample room remains for further innovations and developments.

Trapping of embolic particles in a vessel phantom by cavitation-enhanced acoustic streaming

Cavitation clouds generated by short, high-amplitude, focused ultrasound pulses were previously observed to attract, trap, and erode thrombus fragments in a vessel phantom. This phenomenon may offer a noninvasive method to capture and eliminate embolic fragments flowing through the bloodstream during a cardiovascular intervention. In this article, the mechanism of embolus trapping was explored by particle image velocimetry (PIV). PIV was used to examine the fluid streaming patterns generated by ultrasound in a vessel phantom with and without crossflow of blood-mimicking fluid. Cavitation enhanced streaming, which generated fluid vortices adjacent to the focus. The focal streaming velocity, uf, was as high as 120 cm/s, while mean crossflow velocities, uc, were imposed up to 14 cm/s. When a solid particle 3-4 mm diameter was introduced into crossflow, it was trapped near the focus. Increasing uf promoted particle trapping while increasing uc promoted particle escape. The maximum crossflow Reynolds number at which particles could be trapped, Rec, was approximately linear with focal streaming number, Ref, i.e. Rec = 0.25Ref + 67.44 (R(2) = 0.76) corresponding to dimensional velocities uc = 0.084uf + 3.122 for 20 < uf < 120 cm/s. The fluidic pressure map was estimated from PIV and indicated a negative pressure gradient towards the focus, trapping the embolus near this location.

Locking between a cerebral protection device and a stent-delivering catheter during carotid artery stenting

The cerebral protection device (CPD) itself may cause complications, including locking between the CPD and other devices, that may result in catastrophic outcomes requiring surgical removal of these locked devices. We describe a case of locking between a CPD and the stent-delivering catheter during carotid artery stenting, which was safely rescued by endovascular retrieval. The mechanism underlying locking with the CPD as well as preventive actions and maneuvers for rescuing the situation are discussed.

Protected stent-assisted carotid angioplasty in symptomatic high-risk NASCET-ineligible patients

BACKGROUND AND OBJECTIVES

The North American Symptomatic Carotid Endarterectomy Trial (NASCET) excluded patients with severe medical, angiographic and neurological risk factors. The aim of this study is to determine the safety and efficacy of protected stent angioplasty in these high-risk patients.

METHODS

Sixty-eight consecutive symptomatic NASCET-ineligible patients underwent protected stent-assisted carotid angioplasty. Patients were classified according to surgical risk based on Sundt criteria, and stratified for medical therapy according to stroke risk. Twenty-one patients were classified as Sundt grade 3 (30.8%) and 36 patients as grade 4 (52.9%).

RESULTS

The procedure was technically successful in all patients, with stenosis averaging 82.1% (range 70-99%) before the procedure and 6.3% (range 0-30%) after treatment. There were no periprocedural deaths or major strokes, but two patients had minor, non-embolic stokes (2.9%). During a mean clinical follow-up of 14.4 months (range 1-30 months), no new neurological events occurred in relation to the treated vascular territory.

CONCLUSIONS

Carotid angioplasty with cerebral protection can be performed safely in high-risk patients. During the follow-up period, angioplasty was highly effective in terms of stroke prevention and arterial patency.

Percutaneous transluminal balloon angioplasty and stenting for carotid artery stenosis

BACKGROUND

Endovascular treatment by transluminal balloon angioplasty or stent insertion may be a useful alternative to carotid endarterectomy for the treatment of atherosclerotic carotid artery stenosis. This review updates a previous version first published in 1997 and subsequently updated in 2004 and 2007.

OBJECTIVES

To assess the benefits and risks of endovascular treatment compared with carotid endarterectomy or medical therapy in patients with symptomatic or asymptomatic carotid stenosis.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (last searched January 2012) and the following databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 4), MEDLINE (1950 to January 2011), EMBASE (1980 to January 2011) and Science Citation Index (1945 to January 2011). We also searched ongoing trials registers (January 2011) and reference lists and contacted researchers in the field.

SELECTION CRITERIA

Randomised trials comparing endovascular treatment (including balloon angioplasty or stenting) with endarterectomy or medical therapy for symptomatic or asymptomatic atherosclerotic carotid stenosis.

DATA COLLECTION AND ANALYSIS

One review author selected trials for inclusion, assessed trial quality and extracted data. A second review author independently validated trial selection and a third review author independently validated data extraction. We calculated treatment effects as odds ratios (OR) and 95% confidence intervals (CI), with endovascular treatment as the reference group. We quantified heterogeneity using the I(2) statistic.

MAIN RESULTS

We included 16 trials involving 7572 patients. In patients with symptomatic carotid stenosis at standard surgical risk, endovascular treatment was associated with a higher risk of the following outcome measures occurring between randomisation and 30 days after treatment than endarterectomy: death or any stroke (the primary safety outcome) (OR 1.72, 95% CI 1.29 to 2.31, P = 0.0003; I(2) = 27%), death or any stroke or myocardial infarction (OR 1.44, 95% CI 1.15 to 1.80, P = 0.002; I(2) = 7%), and any stroke (OR 1.81, 95% CI 1.40 to 2.34, P < 0.00001;I(2) = 12%). The OR for the primary safety outcome was 1.16 (95% CI 0.80 to 1.67) in patients < 70 years old and 2.20 (95% CI 1.47 to 3.29) in patients ≥ 70 years old (interaction P = 0.02).The rate of death or major or disabling stroke did not differ significantly between treatments (OR 1.28, 95% CI 0.93 to 1.77, P = 0.13; I(2) = 0%). Endovascular treatment was associated with lower risks of myocardial infarction (OR 0.44, 95% CI 0.23 to 0.87, P = 0.02; I(2) = 0%), cranial nerve palsy (OR 0.08, 95% CI 0.05 to 0.14, P < 0.00001; I(2) = 0%) and access site haematomas (OR 0.37, 95% CI 0.18 to 0.77, P = 0.008; I(2) = 27%).The combination of death or any stroke up to 30 days after treatment or ipsilateral stroke during follow-up (the primary combined safety and efficacy outcome) favoured endarterectomy (OR 1.39, 95% CI 1.10 to 1.75, P = 0.005; I(2) = 0%), but the rate of ipsilateral stroke after the peri-procedural period did not differ between treatments (OR 0.93, 95% CI 0.60 to 1.45, P = 0.76; I(2) = 0%).Restenosis during follow-up was more common in patients receiving endovascular treatment than in patients assigned surgery (OR 2.41, 95% CI 1.28 to 4.53, P = 0.007; I(2) = 55%). In patients with asymptomatic carotid stenosis, treatment effects on the primary safety (OR 1.71, 95% CI 0.78 to 3.76, P = 0.18; I(2) = 0%) and combined safety and efficacy outcomes (OR 1.75, 95% CI 0.92 to 3.33, P = 0.09; I(2) = 0%) were similar to symptomatic patients, but differences between treatments were not statistically significant. Among patients not suitable for surgery, the rate of death or any stroke between randomisation and end of follow-up did not differ significantly between endovascular treatment and medical care (OR 0.22, 95% CI 0.01 to 7.92, P = 0.41; I(2)= 79%).

AUTHORS' CONCLUSIONS

Endovascular treatment is associated with an increased risk of peri-procedural stroke or death compared with endarterectomy. However, this excess risk appears to be limited to older patients. The longer term efficacy of endovascular treatment and the risk of restenosis are unclear and require further follow-up of existing trials. Further trials are needed to determine the optimal treatment for asymptomatic carotid stenosis.

Long-term follow-up of patients after carotid stenting with or without distal protective device in a single tertiary medical center

OBJECTIVE

To evaluate the immediate and long-term clinical outcomes after carotid artery stenting (CAS) with and without protection devices (PDs), compared with carotid endarterectomy (CEA).

METHODS

A total of 116 patients with symptomatic carotid stenosis underwent CAS; 56 patients (48.3%) underwent CAS-PD; and 137 patients underwent CEA.

RESULTS

There were more ipsilateral transient ischemic attacks (TIAs) in the CEA group than in CAS-PD and CAS + PD (4 [3%] vs 1 [1.6%] and 0 respectively, P = 0.02). In the CAS-PD group there were more vertebrobasilar TIAs, ipsi- and contralateral strokes, myocardial infarctions, and death rates in the 30-day postprocedural period. After 8-year follow-up, there were 18 (30%) death cases in the CAS-PD group, 10 death cases (17%) in the CAS + PD patients, and 15 death cases (11%) in the CEA group of patients (P = .02).

CONCLUSION

Our data show that CAS + PD was associated with lower rate of vascular complications and mortality compared with CAS-PD and CEA.

Clinical implications of internal carotid artery flow impairment caused by filter occlusion during carotid artery stenting

BACKGROUND AND PURPOSE

Membrane filters are EPDs, which preserve ICA flow during CAS. However, ICA flow arrest may occur with filter use. This report describes the angiographic, clinical, and histopathologic features of the filter occlusion.

MATERIALS AND METHODS

Sixty-one consecutive patients with cervical carotid stenosis treated by CAS by using a single type of filter device were evaluated. All patients were on dual antiplatelet treatment and fully heparinized. Prestent dilation was performed in all patients. Poststent dilation was performed in 15 patients. Control angiograms were obtained and evaluated after each step of the CAS procedure. All filters were inspected for debris, and if present, histology was obtained.

RESULTS

CAS was successfully performed in all cases with <20% residual stenosis. Filter occlusion occurred in 6 patients (9.8%). It developed immediately after stent deployment in 4, and after a second prestent dilation in 2. Five of the 6 had severe carotid stenosis. In all patients, filter withdrawal led to immediate and complete restoration of ICA flow. In 1 patient, acute embolic M1 occlusion occurred immediately after filter withdrawal but was successfully treated with thrombolysis. None of filter-occlusion group had permanent neurologic deficits. Gross and microscopic examinations demonstrated that the pores of the filters were occluded mainly by fibrin. Postoperative diffusion MR imaging revealed no difference between filter-occlusion and non-filter-occlusion groups.

CONCLUSIONS

ICA flow arrest due to filter occlusion during CAS is relatively common and occurs more frequently in severe stenosis. It resolves rapidly after filter removal and does not appear to worsen outcome.

Tratamento endovascular da reestenose carotídea: resultados em curto prazo

CONTEXTO: O tratamento cirúrgico da reestenose carotídea apresenta alta taxa de lesão neurológica. Contrariamente, o tratamento endovascular da doença obstrutiva carotídea extracraniana tem se tornado mais factível e gradualmente menores taxas de risco cirúrgico vêm sendo reportadas, tornando-se uma opção em situações especiais, e provavelmente poderá ser considerado o tratamento padrão para reestenose carotídea. OBJETIVOS: Avaliar a aplicabilidade, a segurança e a eficácia da angioplastia com o uso do stent (ACS) no tratamento da reestenose carotídea (REC) no intraoperatório e no pós-operatório recente (<30 dias). MÉTODOS: Análise retrospectiva dos pacientes portadores de reestenose carotídea submetidos à angioplastia com stent no período de março 2000 a junho de 2004. RESULTADOS: Foram analisados 19 pacientes com reestenose carotídea. Quatorze pacientes (74%) eram do sexo masculino, com média de idade de 74 anos. Quinze (79%) eram assintomáticos com estenose >80%, enquanto quatro (21%) eram sintomáticos com estenose >70%. Apenas em um paciente não foi utilizado sistema de proteção cerebral. O sucesso técnico foi obtido em todos os casos. Não houve morte ou acidente vascular encefálico no intra ou no pós-operatório recente (30 dias). CONCLUSÃO: O tratamento endovascular da reestenose carotídea mostrou-se uma abordagem factível e segura em curto prazo

Routine Use of Debris Aspiration Before Retrieval of Distal Filter Protection Devices in Carotid Arterial Stenting: Analysis of Captured Debris and Evaluation of Clinical Results

BACKGROUND:

Distal filter protection allows for continuous cerebral perfusion during carotid artery stenting (CAS), although a higher risk of debris migrating into the cerebral arteries compared with other protection systems has been reported.

OBJECTIVE:

To improve the extent of debris capture, we used routine aspiration of blood located proximal to the filter in the internal carotid artery blood column before retrieval of the filter device.

METHODS:

Of 71 CAS procedures with distal filter protection, routine aspiration was performed in 41 procedures. The size and number of debris particles in each aspirated blood sample were measured under a stereoscopic microscope in 30 consecutive procedures with routine aspiration. Occurrence of periprocedural neurological events was compared between 41 procedures with routine aspiration and the other 30 without routine aspiration.

RESULTS:

In the aspirated blood, debris particles ≥500 μm and ≥1000 μm in the longest diameter were observed in 30 (100%) and 28 (93.3%) procedures, respectively. The number of particles ≥1000 μm was significantly larger in the second through fourth blood aspirates vs the first aspirate (P &lt; .05). Occurrence of periprocedural neurological events was significantly less frequent in the routine aspiration group (0 of 41 procedures) than in the conventional method group (7 of 30 procedures) (P &lt; .05).

CONCLUSION:

The use of routine aspiration during CAS with distal filter protection possibly reduced periprocedural neurological events by increasing the proportion of debris captured. To improve the capture of debris particles, at least 4 repeated aspirations are advisable during each CAS procedure.

Classification for carotid artery stenting complications: manifestation, management, and prevention

Carotid artery stenting is a rapidly evolving method for treating carotid artery disease. Various intraprocedural and postprocedural complications have been reported in the literature. However, the absence of a unified classification scheme for these complications makes it difficult, if not impossible, to study their precise incidence, predictors, and management. The aim of this article is to propose the first joint classification of periprocedural complications, to analyze their incidence and etiology, and suggest possible ways to manage and prevent them. This classification is intended to be used as a common platform for prompt recognition, evaluation, treatment, and universal study of the complications during carotid stenting procedures. For this purpose, the opinions of the major experts on carotid interventions worldwide were merged with all the available information reported in the English-language literature to present as accurately as possible the management and prevention of carotid stenting complications according to this proposed classification.

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

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

Carotid stenting and transcranial Doppler monitoring: indications for carotid stenosis treatment

BACKGROUND

Recently, angioplasty and stenting of carotid arteries (CAS) have taken the place of surgery. The aim of our study is to assess the role of transcranial Doppler (TCD) monitoring during CAS to address the embolic complications during the stages of the procedure, with or without embolic cerebral protection devices.

METHODS

A total of 152 patients were submitted to carotid stenting. All patients were submitted to carotid arteries Duplex scanning.

RESULTS

Neurological complications are related to TCD detection of corpuscolate signals in rapid succession. Even if no reduction of the overall incidence rate of microembolic signals (MES) was observed, a decrease in the number of corpuscolate emboli were recorded when a cerebral protection was working.

CONCLUSIONS

According to our study, even in selected patients on the basis of preoperative diagnostic criteria, CAS is burdened by a nonnegligible risk of subclinical embolic ischemic events detected at TCD and confirmed by diffusion-weighted magnetic resonance imaging (DW-MRI).

Initial clinical experience with distal embolic protection using "Filtrap", a novel filter device with a self-expandable spiral basket in patients undergoing percutaneous coronary intervention

We developed a new filter-type distal protection guide wire, Filtrap, that uses a polyurethane filter with 1834 100-μm micropores covering the distal half of a spindle-shaped spiral Ni-Ti basket. The basket is 5 mm in diameter, self-expandable, and is mounted at the distal end of the system. This study aimed to assess the usefulness and safety of Filtrap during percutaneous coronary intervention (PCI). Early angiographic and in-hospital outcomes were reviewed in 14 patients, including 9 acute coronary syndrome patients, treated with Filtrap during PCI. All lesions were located in native coronary arteries but one was located in a saphenous vein graft. The Filtrap was successfully delivered and deployed distal to the lesion in 13 of 14 patients (93%). All PCI procedures including stent implantation were successfully completed except for 2 AMI patients, who ended up with Thrombolysis in Myocardial Infarction (TIMI) 2 coronary flow. One of these 2 patients had a distal embolization which occurred after thrombectomy before Filtrap insertion. The mean time of device insertion was 9.4 ± 3.2 min. Five patients showed transient no-reflow that was completely restored immediately with removal of the device. Embolic debris was entrapped in 8 (62%) of these cases. All patients were free from in-hospital events except for one patient with a large anterior acute myocardial infarction who received an emergency surgery due to a free wall cardiac rupture. These results suggest that the Filtrap is a practical and safe device for embolic protection during PCI.

Catheter-based neurosalvage for acute embolic complication during carotid intervention

OBJECTIVES

Iatrogenic emboli may be released during carotid intervention, causing permanent neurologic complications and catastrophic outcomes. This article reports the procedural details and clinical results of our series of neurosalvage techniques to manage thromboembolic events during carotid procedures.

METHODS

Between March 2003 and December 2007, 342 patients (283 men, 72.1 +/- 8.9 years old, 121 symptomatic) underwent percutaneous stent deployment in 407 cervical internal carotid arteries in our institution. Visible distal embolization with flow occlusion caused neurologic complications in 10 patients (2.5%), and a structured and stepwise neurosalvage approach was attempted.

RESULTS

Guidewire fragmentation and microcatheter injection of heparin and nitroglycerin were performed in all 10 patients as step 1. Intra-arterial thrombolysis was given in four patients and balloon angioplasty in five, as step 2. Intracranial stenting was done in one patient as the last step. Successful angiographic recanalization (Thrombolysis in Myocardial Infarction [TIMI] grade 2-3) occurred in 9 of 10 (90%). Residual neurologic sequel was observed in five, including three patients with hemorrhage complications (1 received emergent craniotomy). There was no neurologic mortality in this series.

CONCLUSIONS

Acute embolic complication during carotid artery stenting can be managed by catheter-based neurosalvage with effective angiographic recanalization and marginal clinical success.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Carotid stenting and bivalirudin with and without vascular closure: 3-year analysis of procedural outcomes

OBJECTIVES

The purpose of this study was to examine the outcome of carotid stenting using bivalirudin and the influence of vascular closure devices (VCD) on the incidence and severity of peri-procedural hypotension.

BACKGROUND

Bivalirudin, a short-acting direct thrombin inhibitor, has been shown to be an effective anticoagulant in coronary interventions, with less risk of bleeding compared with heparin. Routine use of VCD has become the standard of care, facilitating patient ambulation after percutaneous carotid and coronary interventions. The combined use of these two therapies (bivalirudin and VCD) may improve outcomes in carotid interventions where prolonged patient immobilization may exacerbate hypotension following stenting.

METHODS

A total of 514 patients underwent 536 carotid stenting procedures in the 3-year period from September 2004 to September 2007. All patients received adjunctive bivalirudin, with and without VCD. This cohort was analyzed for peri-procedural and 30-day clinical outcomes and length of hospitalization.

RESULTS

Thirty-day stroke and death rate was 1.7%. A total of 83 patients (15.4%) experienced intra- or post-procedural hypotension (systolic BP < 80 mm Hg). There were four (0.7%) major bleeding complications requiring transfusion, and length of stay was delayed more than 24 hr in five patients (0.93%), all of whom were in the manual compression group.

CONCLUSIONS

This was a negative study, with no significant difference on prolonged hypotensive events in patients with vascular closure device and bivalirudin, compared with those with manual compression and bivalirudin. Vascular closure devices were safe and effective with a low incidence of complications. In carotid artery stenting, bivalirudin is safe with low incidence of major bleeding and acceptable 30-day adverse event rates (stroke and death).

Atheroembolic renal disease

Atheroembolic renal disease develops when atheromatous aortic plaques rupture, releasing cholesterol crystals into the small renal arteries. Embolisation often affects other organs, such as the skin, gastrointestinal system, and brain. Although the disease can develop spontaneously, it usually develops after vascular surgery, catheterisation, or anticoagulation. The systemic nature of atheroembolism makes diagnosis difficult. The classic triad of a precipitating event, acute or subacute renal failure, and skin lesions, are strongly suggestive of the disorder. Eosinophilia further supports the diagnosis, usually confirmed by biopsy of an affected organ or by the fundoscopic finding of cholesterol crystals in the retinal circulation. Renal and patient prognosis are poor. Treatment is mostly preventive, based on avoidance of further precipitating factors, and symptomatic, aimed to the optimum treatment of hypertension and cardiac and renal failure. Statins, which stabilise atherosclerotic plaques, should be offered to all patients. Steroids might have a role in acute or subacute progressive forms with systemic inflammation.

Differences in carotid plaque content of macrophages, T cells and MMP-9 between patients with embolic and hemodynamic cerebral ischemia due to symptomatic carotid stenosis

BACKGROUND

Cerebral ischemia in patients with carotid artery atherosclerosis is most often caused by thromboembolism, while hemodynamic stroke mechanism is rare. Differences in plaque inflammation according to stroke mechanism are an understudied issue. The purpose of this pilot study was to compare carotid plaque inflammation in patients with thromboembolic and hemodynamic cerebral ischemia.

METHODS

We included 6 patients with hemodynamic and 27 with embolic cerebral ischemia who had carotid endarterectomy (CEA). We compared plaque morphology markers (macrophages, T cells, MMP-9, plaque rupture, surface thrombus, intraplaque hemorrhage, lipid core) between patients with hemodynamic and embolic cerebral ischemia and assessed vascular events and deaths during the first year post CEA.

RESULTS

Compared to patients with hemodynamic mechanism, those with embolic mechanism showed a higher median (interquartile range) content of T cells/mm(2) [49.66 (21.26-71.39) vs. 10.28 (7.05-13.87); P=0.0005] and higher median total percentages of macrophage area [2.81% (1.69-4.09) vs. 0.99% (0.57-1.50); P=0.003] and MMP-9 area [0.63% (0.42-1.01) vs. 0.25% (0.05-0.45); P=0.007]. Signs of plaque instability such as plaque rupture, surface thrombus and intraplaque hemorrhage showed a tendency to be more pronounced in patients with thromboembolism. The incidences of vascular events and the survival rates in the first year after CEA were similar in the two groups.

CONCLUSIONS

Major differences in plaques related to stroke mechanism were found in patients with symptomatic carotid stenosis. However, further investigations are necessary to validate our results. Identification of stroke mechanism may improve risk stratification and could help to identify the most suitable secondary stroke prevention strategy.

Intravascular ultrasound: principles and cerebrovascular applications

Intravascular sonography is a valuable tool for the morphologic assessment of coronary atherosclerosis and the effect of pharmacologic and nonpharmacologic interventions on the progression or stabilization of atherosclerosis. An analysis of the different modes, applications, and limitations is provided on the basis of review of existing data from multiple clinical case studies, trials, and mechanistic studies. Intravascular sonography has been used to assess the outcomes of different percutaneous interventions, including angioplasty and stent implantation, and to provide detailed characterization of atherosclerotic lesions, aneurysms, and dissections within the cerebrovascular circulation. Evolution of intravascular sonographic technology has led to the development of more sophisticated diagnostic tools such as color-flow, virtual histology, and integrated backscatter intravascular sonography. The technologic advancement in intravascular sonography has the potential of providing more accurate information prior, during, and after a medical or endovascular intervention. Continued assessment of this diagnostic technique in both the intracranial and extracranial circulation will lead to increased use in clinical practice with the intent to improve outcomes.

Endovascular treatment of peripheral vascular disease

Peripheral arterial disease (PAD) affects about 27 million people in North America and Europe, accounting for up to 413,000 hospitalizations per year with 88,000 hospitalizations involving the lower extremities and 28,000 involving embolectomy or thrombectomy of lower limb arteries. Many patients are asymptomatic and, among symptomatic patients, atypical symptoms are more common than classic claudication. Peripheral arterial disease also correlates strongly with risk of major cardiovascular events, and patients with PAD have a high prevalence of coexistent coronary and cerebrovascular disease. Because the prevalence of PAD increases progressively with age, PAD is a growing clinical problem due to the increasingly aged population in the United States and other developed countries. Until recently, vascular surgical procedures were the only alternative to medical therapy in such patients. Today, endovascular practice, percutaneous transluminal angioplasty with or without stenting, is used far more frequently for all types of lower extremity occlusive lesions, reflecting the continuing advances in imaging techniques, angioplasty equipment, and endovascular expertise. The role of endovascular intervention in the treatment of limb-threatening ischemia is also expanding, and its promise of limb salvage and symptom relief with reduced morbidity and mortality makes percutaneous transluminal angioplasty/stenting an attractive alternative to surgery and, as most endovascular interventions are performed on an outpatient basis, hospital costs are cut considerably. In this monograph we discuss current endovascular intervention for treatment of occlusive PAD, aneurysmal arterial disease, and venous occlusive disease.

V, Karakhanian WK, Caffaro RA. Técnica para quantificação e qualificação de material coletado em filtros de proteção cerebral

Contexto: A qualidade e a quantidade de partículas coletadas em filtros de proteção cerebral (FPC) durante angioplastia transluminal percutânea com stent (ATPS) podem esclarecer a importância desses dispositivos no tratamento de estenoses carotídeas. Objetivos: Analisar o conteúdo retido por FPC em pacientes submetidos a ATPS de artéria carótida interna com nova técnica de análise qualiquantitativa. Métodos: O material coletado em 10 FPC durante ATPS da bifurcação da carótida em pacientes com alto risco cirúrgico foi submetido a análise microscópica qualiquantitativa. Fotografias digitais das lâminas com material corado com hematoxilina e eosina foram analisadas com o programa Axio Vision LE Release 4.1, que calculou a área das partículas em micrômetros/metro quadrado (µm²). Resultados: O exame histopatológico evidenciou material em 100% dos filtros consistindo predominantemente de restos hemáticos, cristais de colesterol e cálcio. A área média de fragmentos coletados foi expressiva (1.570.310 µm²), e houve ampla variância desses valores. Conclusões: Os FPC coletam quantidade importante de fragmentos de placas de ateroma, e a grande variância nas quantidades de material coletado pode estar associada com a gravidade da lesão, motivo pelo qual se tornam relevantes estudos que utilizem técnica padronizada para a quantificação desses fragmentos e para a compreensão de seu real significado clínico.

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.