Routine use of cerebral protection during carotid artery stenting: results of a multicenter registry of 753 patients

From surgical clamping to endovascular flow arrest/reversal: the concept behind the system

Carotid artery lesions are frequently composed of friable, thrombotic, ulcerated and/or hemorrhagic materials which can embolize during surgical or endovascular interventions. The use of embolic protection devices (EPD) during carotid angioplasty and stenting (CAS) has been proven to be associated with a reduction of the embolic load. Many studies indicate that the clinical results of CAS are comparable with the best surgical series, when EPD are routinely applied. The proximal EPD work by interrupting or reversing the blood flow in the common carotid artery/internal carotid artery (CCA/ICA). Once established the endovascular flow arrest/reversal, these systems have the advantages of promoting a protected crossing of the lesion and blocking both macro-emboli and micro-emboli. Moreover, proximal neuroprotection implies no manipulation of the device in the distal ICA, neither during device deployment nor during device retrieval, and reduces the risk of arterial spasm, dissection, or intimal damage. The choice between transfemoral and transcervical proximal EPD should account for different factors: local availability, operator expertise, and patient characteristics including anatomical features precluding flow arrest/reversal (e.g., incomplete circle of Willis), femoral access (e.g., unfavorable aortic arch anatomy), or transcervical access (e.g., diseased CCA).

Is it possible to prevent cerebral embolization by improving the design and technology of carotid stent implantation?

INTRODUCTION

The prevention of atherosclerotic plaque fragmentation during carotid artery stenting is a fundamental problem in decreasing the risk of disability of patients. The goal of this review is to clarify whether the stent design can have a decisive impact on the rate of intraoperative and postoperative complications.

AREAS COVERED

Different designs of the carotid stents are briefed and the advantages and disadvantages of different stent designs are discussed as well as the results of their clinical use. Various solutions are presented to reduce cerebral embolism during carotid artery stenting.

EXPERT OPINION

There is no conclusive evidence for the benefits of closed cell and hybrid stents. The stent design cannot completely resolve the problem of cerebral embolism. Most of the events of cerebral microembolism occur at the stages of stent delivery rather than protrusion of an atherosclerotic plaque in the long-term follow-up. Most likely, minimization of the risks for periprocedural and postprocedural strokes requires not only the new solutions in stent design as well as the corresponding delivery systems and brain embolic protection systems, but also the new strategies of preprocedural drug stabilization of the atherosclerotic plaque in the carotid artery. Abbreviations: CAS, carotid artery stenting; CE, carotid endarterectomy; DW-MRI, diffusion-weighted magnetic resonance imaging; ECA, external carotid artery; ICA, internal carotid artery; IVUS, intravascular ultrasound examination; OCT, optical coherence tomography.

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.

Impact of plaque dilation before carotid artery stent deployment

OBJECTIVE

Plaque stability is of utmost importance for stroke prevention in the perioperative period (within 24 hours) following carotid artery stenting (CAS). Although carotid plaque is entrapped between stent struts after stent deployment, postdilation can cause a scissoring effect on the plaque, increasing the risk of postprocedural embolic events due to plaque prolapse. Maximum carotid plaque dilation before stent deployment may reduce this risk. This study analyzed the effect of maximum dilation of the carotid plaque before stent deployment (max-pre-SD) or after stent deployment (post-SD) on macroscopic plaque debris, hemodynamic depression (HD), and immediate major adverse events.

METHODS

This prospective nonrandomized multicenter study analyzed patients treated for carotid artery stenosis with CAS from January 2014 to August 2016. Clinical and morphologic characteristics and operative details were analyzed with logistic regression analysis for macroscopic debris and HD. The number of microembolic signals (MESs) was assessed by transcranial Doppler and analyzed.

RESULTS

A total of 309 patients were enrolled and treated with standard CAS performed using a proximal occlusion cerebral embolic protection device; 149 received max-pre-SD and 160 were treated with post-SD. Technical success was achieved in 100% of cases. Macroscopic debris and HD were significantly different between the two groups in favor of max-pre-SD (P < .001). A significant difference in intraprocedural MESs between the groups was detected. Compared with post-SD, max-pre-SD significantly reduced mean MES counts (8.1% vs 68.1%; P < .001). Patients treated with post-SD had a significantly increased risk of MESs in the immediate postoperative period compared with patients treated with max-pre-SD (41.9% vs 1.3%; P < .001).This result was mainly due to the small number of events encountered. Patients treated with post-SD had a 12-fold increased risk of macroscopic debris collection (odds ratio [OR], 12.36; 95% confidence interval [CI], 5.68-26.87; P < .001) and an 18 times increase in HD risk (OR, 17.80; 95% CI, 5.27-60.17; P < .001) compared with patients treated with max-pre-SD. The heterogeneous, mainly echolucent plaque type significantly highly increased the risk of macroscopic debris (OR, 78.45; 95% CI, 8.70-707.09; P < .001) while acting as a protective factor against HD (OR, 0.02; 95% CI, 0.006-0.11; P < .001) along with echogenic or echolucent complex plaques with irregular surface plaque types (OR, 0.10; 95% CI, 0.031-0.336; P < .001). No significant differences between groups (max-pre-SD group and post-SD) were detected in immediate major adverse events (minor stroke, 2.0% and 2.5% [P = .461]; major stroke, 0% and 0.6% [P = .334], respectively).

CONCLUSIONS

Max-pre-SD seems to be a safe and feasible technical modification to the CAS procedure. Macroscopic debris, HD, and MESs are significantly reduced compared with CAS with post-SD. Further research with larger, randomized cohorts of patients is required to establish the superiority of this technical modification.

Vascular Anatomy and Not Age is Responsible for Increased Risk of Complications in Symptomatic Elderly Patients Undergoing Carotid Artery Stenting

BACKGROUND

Various studies have suggested that age ≥80 years is associated with a higher rate of complications after carotid artery stenting (CAS). The Buffalo Risk Assessment Scale (BRASS) predicts complications in symptomatic patients undergoing CAS. Application of the BRASS has shown the ability to improve patient selection. We used the BRASS system to evaluate whether the higher rate of complications associated with CAS in the elderly is related to vascular anatomy.

METHODS

A retrospective review of CAS was performed at our institution over 7 years. Demographic information, anatomic characteristics, BRASS categorization, and outcome measures were compared between elderly (≥80 years) and younger patients (<80 years).

RESULTS

The study included 447 patients: 335 patients (75%) <80 years and 112 patients (25%) ≥80 years. There were significantly more elderly patients in the high-risk BRASS category (P < 0.01), and more young patients in the low-risk BRASS category (P = 0.04). The complication rates in the 2 groups were similar. Older patients were more likely to harbor complex vascular anatomy: they had significantly higher rates of types II and III aortic arches (P = 0.01 and P < 0.01, respectively), higher percentage of tortuous carotid vessels (P < 0.01), and higher rates of hostile anatomy for deployment of distal embolic protection devices (P = 0.02).

CONCLUSIONS

Complex vascular anatomy, rather than age, is the key factor behind the higher CAS-associated complication rate in the elderly. Complications can be avoided through proper patient selection and stratifying patients based on anatomic characteristics, which can be achieved through the BRASS scoring system.

Carotid artery stenting in a single center, single operator, single type of device and 15 years of follow-up

Background

Revascularization with carotid stent (CAS) is considered the therapeutic alternative to endarterectomy (CEA). However, its role compared to CEA remains questioned, mainly due of the heterogeneity of long-term results. The objective of this study was to report the efficacy and durability of CAS in terms of stroke prevention in a "real world experience".

Method

This was a single-center retrospective analysis of 344 patients treated with CAS between January 2001 and December 2015.The primary outcome of the trial was stroke, myocardial infarction, or death during a periprocedural period or any stroke event over a 15-year follow-up. The secondary aim was to identify risk factors for 30-day complications, long-term neurological complications, and intra-stent restenosis.

Results

The primary composite end point (any stroke, myocardial infarction, or death during the periprocedural period) was 2.3%. The use of an EPD was protective against major complications.Long-term follow-up was achieved in 294 patients (85,5%) with a median of 50 months (range 0-155 months). Fifty-six (16,3%) died within this period, most commonly of nonvascular causes (4 patients had stroke-related deaths). During the follow-up period, 8 strokes and 3 TIAs were diagnosed (3.2%).ISR determined by sequential ultrasound was assessed in 4.4% of the patients and remained asymptomatic in all but 2 patients (0.6%). All patients with restenosis underwent revascularization with balloon angioplasty.

Conclusion

The long-term follow-up results of our study validate CAS as a safe and durable procedure with which to prevent ipsilateral stroke, with an acceptable rate of restenosis, recurrence and mortality.

Early results of endovascular treatment of patients with bilateral stenoses of the internal carotid arteries using proximal protection systems at 30-day follow-up

BACKGROUND

Although surgical endarterectomy remains the treatment of choice for carotid artery stenosis, carotid artery stenting (CAS) with use of proximal protection systems (PPS) plays an very important role as alternative treatment modality, especially in patients with critical, symptomatic lesions. This study was single-centre study to evaluate the technical and clinical success of proximal protection devices as the first choice for embolic protection in symptomatic and asymptomatic carotid stenosis in patients with bilateral, advanced lesions of carotid arteries (bilateral stenoses or stenosis and occlusion).

METHODS

This was a post hoc analysis, with 30-day follow up. We analyzed results of treatment of 38 patients who underwent 38 CAS with PPS, 17 such procedures in asymptomatic (group A), and 21 in symptomatic individuals (group B). The GORE^® Flow Reversal System (W.L. Gore, Flagstaff, AZ, USA) was used in 2 patients, and the Mo.Ma Ultra device (Medtronic, Minneapolis, MN, USA) in 36 patients. Mean age was 68±7 years, 65% percent of patient were male.

RESULTS

There were no procedural and during 30-day follow-up neurologic events. Intolerance of occlusion system occurred in 4 patients (11%) in both groups with any later symptoms. Risk factors of this adverse event comprised: lesions of the left internal carotid lesion and coexisiting diabetes mellitus.

CONCLUSIONS

CAS in high risk patients with bilateral lesions of carotid arteries with the use of PPS seems to be a relatively very safe procedure.

Patient- and lesion-tailored algorithm of endovascular treatment for arterial occlusive disease of extracranial arteries supplying the brain: safety of the treatment at 30-day follow-up

Introduction

Although surgical endarterectomy remains the treatment of choice for carotid artery stenosis, stenting plays an important role as an alternative treatment modality, especially in high-risk patients. The actual safety profile associated with stenting procedures is probably better than that reported by randomized controlled trials.

Aim

To assess the safety of stent implantations in extracranial arteries supplying the brain, and also to identify risk factors associated with this procedure.

Material and methods

This was a post hoc analysis, with 30-day follow-up. We analyzed the results of treatment of 372 patients who underwent 408 procedures, 197 such procedures in asymptomatic, and 211 in symptomatic individuals. Stenting procedures were performed using a technique and armamentarium which were tailored to the type and anatomy of lesions.

Results

There were 6 (1.5%) strokes, including 2 (0.5%) major strokes, 1 ipsi- and 1 contralateral, and 4 (1.0%) minor strokes. In asymptomatic patients there was 1 (0.3%) minor stroke. Transient ischemic attacks occurred in 5 (1.2%) patients. There were 2 (0.5%) non-STEMI myocardial infarctions and 2 (0.5%) non-stroke related fatalities. Risk factors of these adverse events were diabetes mellitus, lesions localized in a tortuous segment of the artery, embolic material in the filter and bilateral stenoses of carotid arteries. Additional risk factors in asymptomatic patients were renal impairment and advanced coronary artery disease; and in symptomatic patients, grade 3 arterial hypertension, dislipidemia, cigarette smoking and lesions requiring predilatation.

Conclusions

Stenting procedures of extracranial arteries supplying the brain, which are tailored to the type and anatomy of lesions, seem to be relatively safe.

Endovascular management of carotid artery dissections with the use of new generation stents and protection systems

Dissection of the internal carotid artery (ICA) is a rare disease, but in young patients is responsible for about 20% of cerebral events. We presented three different cases of ICA dissection, including one iatrogenic and two spontaneous ones, which were successfully managed endovascularly, with the use of different techniques, different protection devices and stents. In this article, the clinical management and details of procedures were described.

Subclinical ischemic events in patients undergoing carotid artery stent placement: comparison of proximal and distal protection techniques

OBJECTIVE

To determine the relative effectiveness of proximal and distal protection in prevention of cerebral ischemic events during carotid artery stent (CAS) placement using diffusion-weighted MRI (DW-MRI).

METHODS

We analyzed data from patients who had undergone DW-MRI before and within 24 hours of CAS for symptomatic internal carotid artery (ICA) stenosis (with last ischemic events within 3 months). The study was performed prospectively; patients were not randomized, and were treated either with a proximal balloon occlusion system (Mo.Ma; Invatec, Roncadelle, Italy) or filter-type distal protection device (Spider device; ev3, Plymouth, Minnesota, USA).

RESULTS

Of the 45 patients (mean age±SD: 66.9±9.8 years; 73.3% were men) who underwent CAS, 19 had proximal protection and 26 distal protection. New ischemic lesions were detected in 26/45 patients on DW-MRI scans obtained within 24 hours after CAS. The proportion of patients with new lesions on DW-MRI at 24 hours was not different between the two groups (47.4% vs 65.4% for proximal and distal protection, respectively). The mean number of new ischemic lesions on post-CAS DW-MRI was non-significantly higher in patients who underwent CAS with distal protection (2.80±3.54 for proximal protection vs 4.96±5.11 for distal protection; p=0.12). The proportion of patients with new lesions >1 cm did not differ between the two groups (5.3% for proximal protection vs 11.5% for distal protection; p=0.62). There was no difference in the rates of ischemic stroke between patients who underwent CAS treatment using proximal and distal protection (5.3% vs 7.7%; p=1.000).

CONCLUSIONS

We found a relatively high rate of new ischemic lesions in patients undergoing CAS with cerebral protection. There was no difference in the proportion of patients with new lesions between patients treated using distal protection and those treated using proximal protection.

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.

Entrapment of a Cerebral Embolic Protection Device

Cerebral protection devices have significantly reduced the incidence of embolic events in patients undergoing carotid stenting. With the increasing availability of such devices an awareness of the potential complications associated with their deployment is essential. Here we report a patient with entrapment of a filter device within a carotid stent that required surgical removal. The mechanisms underlying this complication and measures to prevent its occurrence are discussed.

Carotid stenting versus endarterectomy for the treatment of carotid artery stenosis: Contemporary results from a large single center study

OBJECTIVE

To compare the complication rates associated with carotid endarterectomy (CEA) versus carotid artery stenting (CAS).

BACKGROUND

Carotid stenosis is a well-known cause of stroke and increased mortality. The safety of carotid revascularization may be related to symptom status, medical comorbidities, use of embolic protection devices, as well as operator experience and these factors may vary across patient populations within a single operating center.

METHODS

We retrospectively analyzed patients with carotid artery stenosis admitted to our hospital for carotid revascularization between January 1, 2007 and December 1, 2013. The primary end point was a composite endpoint of periprocedural death, stroke, and myocardial infarction (MI).

RESULTS

Of the 718 patients admitted for carotid revascularization 525 (73.1%) underwent CEA and 193 (26.9%) underwent CAS. Both groups demonstrated similar rates of the composite endpoint, MI, and death; the stenting group demonstrated a higher rate of stroke (4.2% vs. 1.3%; P = 0.020). Adjusting for baseline medical comorbidities and symptom status mitigated this difference (P = 0.091 and 0.113, respectively). When stratified by department performing CAS, there was a significant difference in the occurrence of stroke (P = 0.033), which likewise disappeared in the multivariate regression analysis.

CONCLUSION

The risk of the composite endpoint did not differ significantly between those undergoing CAS versus CEA. The stenting group demonstrated a higher rate of periprocedural stroke, which was also apparent when patients were stratified by stenting department. These differences were likely driven by variation in baseline medical comorbidities and symptom status. © 2016 Wiley Periodicals, Inc.

A Novel Approach to Overcome Stent Strut Entrapment of the Distal Filter Retrieval Catheter during Vertebral Artery Stenting: The "Olive-Tipped" Technique

We developed an "olive-tipped" technique for preventing the distal filter retrieval catheter from entrapment in the stent struts during retrieval procedures after stent deployment and which we used in 2 vertebral artery stenting cases. A new wire entry port was made in the catheter at the transition of larger and smaller lumen to permit passage of a low-profile balloon into the lumen of the retrieval catheter. When the balloon was inflated across the retrieval catheter tip, a smoother profile was created which eliminated the sharp step between the catheter tip and the filter wire. The retrieval catheter could then be advanced easily through the stent struts using this modified system.

Beta-blocker use is associated with lower stroke and death after carotid artery stenting

BACKGROUND

Proper selection of patients for carotid artery stenting (CAS) remains controversial despite multiple controlled trials. This relates in part to differences in interpretation of the relative importance of myocardial vs stroke complications after the procedure by different specialties and a lack of granular clinical data to analyze outcomes outside the large clinical trials. The objective of this study was to assess the effect of preoperative medications, procedure parameters, and patient characteristics on outcomes of CAS performed in a multispecialty national database.

METHODS

We analyzed all patients who underwent CAS between 2005 and 2014 in the Vascular Quality Initiative. A multivariate logistic regression model was built to assess the effects of age, gender, comorbidities, smoking, preprocedure medications, procedure details, and hypotension or hypertension that required intravenous medication on 30-day death or stroke rates.

RESULTS

A total of 5263 patients underwent CAS (mean age, 70 years; 63% male). The 30-day stroke/death rate was 3.4% (1.5% minor stroke, 0.9% major stroke, and 1.2% death; 40% of patients who had major strokes died within 30 days), and the myocardial infarction rate was 0.8%. Postprocedural hypertension requiring treatment occurred in 519 cases (9.9%), and it was associated with a 3.4-fold increase in stroke/death (odds ratio, 3.39; 95% confidence interval, 2.30-5.00; P < .0001). Preprocedural beta-blocker use for >30 days was associated with a 34% reduction in the stroke/death risk (odds ratio, 0.66; 95% confidence interval, 0.46-0.95; P = .025) compared with nonuse. Beta-blocker use was not associated with postprocedural hypotension. Other predictors of postoperative stroke and death included age, symptomatic status, diabetes (type 1 or type 2), and postprocedural hypotension, whereas prior carotid endarterectomy and distal embolic protection use were protective.

CONCLUSIONS

Postprocedural hypertension and hypotension that require treatment are both strongly associated with periprocedural stroke/death after CAS. Beta blockers significantly reduce the stroke/death risk associated with carotid stenting and should be investigated prospectively for potential use during CAS.

High-Risk Factors in Symptomatic Patients Undergoing Carotid Artery Stenting With Distal Protection

BACKGROUND:

Demographics and vascular anatomy may play an important role in predicting periprocedural complications in symptomatic patients undergoing carotid artery stenting (CAS).

OBJECTIVE:

To predict factors associated with increased risk of complications in symptomatic patients undergoing CAS and to devise a CAS scoring system that predicts such complications in this patient population.

METHODS:

A retrospective study was conducted that included patients who underwent CAS for symptomatic carotid stenosis during a 3-year period. Demographics and anatomic characteristics were subsequently correlated with 30-day outcome measures.

RESULTS:

A total of 221 patients were included in the study. The cumulative rate of periprocedural complications was 7.2%, including stroke (3.2%), myocardial infarction (3.2%), and death (1.4%). Renal disease increased the risk of all complications. National Institutes of Health Stroke Scale score ≥10 at presentation, difficult femoral access, and diseased calcified aortic arch increased the risk of stroke and all complications. Type III aortic arch correlated with increased risk of stroke. Pseudo-occlusion and concentric calcification of the carotid artery increased the risk of myocardial infarction, death, and all complications. Carotid tortuosity and anatomy hostile to the deployment of distal protection devices increased the risk of stroke, myocardial infarction, death, and all complications.

CONCLUSION:

Our results suggest that CAS should be avoided in patients with multiple anatomic risk factors. High presenting National Institutes of Health Stroke Scale score and renal disease also increase the complication risk. The CAS scoring system devised here is simple, reproducible, and clinically valuable in predicting complications risk in symptomatic patients undergoing CAS.

Poststent ballooning is associated with increased periprocedural stroke and death rate in carotid artery stenting

BACKGROUND

Whereas carotid endarterectomy (CEA) remains the "gold standard" treatment, given its low complication rate, carotid artery stenting (CAS) has emerged as a valid alternative in patients with prohibitive surgical risks. However, the application of CAS has been scrutinized, given its increased perioperative risk in comparison to CEA. Operators follow general guidelines in intraoperative techniques in CAS. However, few of those are evidence based. We believe that a specific outcome-driven examination of the effect of pre- and poststent deployment ballooning is warranted. The objective of this study was to analyze the effect of prestent ballooning (pre-SB) and poststent ballooning (post-SB) on hemodynamic depression (HD) and perioperative stroke or death.

METHODS

We performed a retrospective analysis of all patients who had CAS between 2005 and 2014 in the Vascular Quality Initiative database. Logistic regression analyses of the effect of different pre-SB and post-SB combinations on HD and the 30-day stroke and death rate were performed. We excluded patients who had no protection device, those with isolated common carotid artery lesions, and those who had no ballooning at all. The models controlled for patient age, gender, comorbidities, smoking status, symptomatic status, history of previous ipsilateral CEA, preoperative medications, and ipsilateral degree of stenosis.

RESULTS

A total of 3772 patients who underwent CAS were included for analysis. Average age of patients was 69.8 ± 9.6 years, with 63% being male. The overall perioperative stroke and death rate was 3.0%. Compared with pre-SB only technique, the combined pre-SB and post-SB technique had a 2.1-fold increase in HD (odds ratio, 2.13; 95% confidence interval, 1.51-3.01; P < .001) and 2.4-fold increase in perioperative stroke and death rate (odds ratio, 2.37; 95% confidence interval, 1.01-5.62; P < .050).

CONCLUSIONS

Compared with pre-SB alone, the use of post-SB increases the chances of perioperative HD and stroke and death rate in patients undergoing CAS. Post-SB should be used only in those cases with severe residual stenosis.

Design of the rosuvastatin pretreatment to reduce embolization during Carotid Artery Stenting trial

BACKGROUND

Carotid artery stenting (CAS) is a worldwide diffuse intervention, but may be associated with distal plaque component embolization, and sometimes major and minor stroke. Statin use has been demonstrated to reduce atherosclerotic plaque burden, but its effect in reducing distal embolization during carotid stenting has not yet been well validated.

AIMS

With the Rosuvastatin Pretreatment to Reduce Embolization during Carotid Artery Stenting trial, we aim to discover if a pretreatement with high doses of rosuvastatin in dyslipidemic patients is able to reduce periprocedural cerebral ischemic complications following carotid stenting.

METHODS

This is a phase III prospective, randomized controlled trial. All consecutive patients with asymptomatic carotid stenosis at least 80% will be randomized to a 6-week rosuvastatin treatment followed by carotid stenting, and to direct carotid stenting. Carotid stenting will be performed following common practice with distal or proximal embolic protection. The primary efficacy end point of the trial will be the prevalence of 'relevant' embolization during CAS, as a surrogate end point for cerebral ischemic complications. Other laboratory and clinical data will be registered and patients will be followed up to 1 year. In order to obtain the expected superiority of statin pretreatment on primary end point, a population of 130 patients will be enrolled into the study.

CONCLUSION

In conclusion, with the Rosuvastatin Pretreatment to Reduce Embolization during Carotid Artery Stenting trial, we want to evaluate whether a high dose of rosuvastatin for 6 weeks before CAS in asymptomatic patients with severe carotid stenosis is able to reduce the rate of plaque embolization during the procedure, thus suggesting a possible reduction in cerebral ischemic complications.

Design and development of mechanical embolic protection devices

Carotid angioplasty and stenting (CAS) is rapidly becoming an acceptable alternative to carotid endarterectomy in many patients. Much of the success of CAS is credited to advances in equipment dedicated to this minimally invasive approach. Lower profile delivery systems, tapered stent designs and most importantly, development of mechanical cerebral embolic protection devices (EPDs) have contributed to a reduction in periprocedural neurological complications that now rival results of carotid endarterectomy. Despite a lack of level one evidence in support of EPDs, a meta-analysis as well as two recent institutional reports of CAS with and without EPDs suggest a reduced stroke risk when a mechanical protection device is incorporated as part of the procedure. Since the original description by Theron and colleagues, embolic protection systems are markedly improved in ease of use and effectiveness. The three primary groups of EPDs are distal balloon occlusion, distal filtration and proximal occlusion. Although the ideal EPD has yet to materialize, this review provides insight into current design systems and the accompanying strengths and weaknesses of each.

[Carotid artery stenting technique]

Over the past 25 years carotid artery stenting (CAS) has emerged as an alternative to carotid endarterectomy (CEA). Most of all younger patients and symptomatic patients with contralateral carotid artery occlusion particularly benefit from CAS. To achieve an optimal result with CAS, patient selection and even more important, knowledge and experience of the interventionist is crucial. The periprocedural complication rate of CAS in large experienced centers is lower (2-3%) than those in randomized trials. Several different devices are now available which allow the procedure to be tailored according to patient anatomy and lesion complexity. Complications like hyperperfusion syndrome and intracerebral bleeding, rupture of side branches of the external or internal carotid artery as well as problems caused by slow flow can be widely avoided by adequate experience.

Comparison between proximal versus distal protection devices in 287 cases of carotid revascularization using angioplasty and stenting: periprocedure complications, morbidity, and mortality

BACKGROUND

Embolic protection devices may decrease periprocedural thromboembolic complications during carotid angioplasty and stenting (CAS). When using proximal-protection devices (PPDs), protection starts before crossing the lesion. However, in the medical literature, its use is scarcely reported compared with that of distal-protection filters (DPDs). The objective of this study was to compare periprocedure complications, morbidity, and mortality among 287 consecutive cases of CAS performed with PPDs or DPDs.

PATIENTS AND METHODS

This was a retrospective analysis of 287 patients treated with CAS at our hospital between January 2006 and March 2012. Periprocedure complications, morbidity, and mortality at 30 days, including ischemic stroke or transient ischemic attack, reperfusion syndrome, myocardial infarction (MI), and death, were globally registered, and the results in PPD and DPD groups were compared.

RESULTS

Two hundred eight patients were treated with DPD and 79 with PPD; 80.8 % were symptomatic. CAS procedures performed with PPD presented a statistically significant greater grade of stenosis than those with DPD (82.5 vs. 74.5 %, p < 0.001). Death rates were 1.9 and 1.3 %; stroke rates were 4.3 and 3.8 %; MI rates were 1.4 and 1.3 %; and total morbidity and mortality rates were 6.2 and 5 % (DPD and PPD groups, respectively); all differences were nonstatistically significant. No statistical difference was found between symptomatic and asymptomatic patients.

CONCLUSION

Carotid angioplasty and stenting is a safe procedure to treat carotid disease in our patients. PPDs are not always associated with a greater risk of periprocedure complications, morbidity, and mortality than DPDs despite the greater grade of carotid stenosis in the PPD group. This observation may be of interest in the design of future studies with CAS.

Carotid revascularization: a systematic review of the evidence

OBJECTIVE AND BACKGROUND

The aim of this study is to provide an evidence-based review of the periprocedural safety and long-term effectiveness of carotid artery stenting (CAS) compared to carotid endarterectomy (CEA), with particular attention paid to the use of embolic protection devices and patients at high risk for CEA.

METHODS

Electronic databases (Ovid Medline, Cochrane central register of controlled trials, Pubmed, and Embase) were searched to identify: (1) randomized controlled trials (RCT) comparing outcomes of CEA and CAS, and (2) prospective clinical trials assessing the safety of CAS in patients at high surgical risk. Pooled incidence rates and one-sided 95% confidence interval for the periprocedural and long-term composite end-point of stroke, myocardial infarction, or death among high surgical risk patients were generated and compared to objective performance criteria (OPC) reported by previous trials.

RESULTS

Six RCTs and 14 prospective clinical trials met our search criteria. Selected RCTs showed inconsistency in reported periprocedural and long-term outcome rates. Pooled incidence rates of the periprocedural and long-term composite end-point of stroke, myocardial infarction or death in high surgical risk candidates were 5.59% and 7.92%, respectively. These results were noninferior to selected OPCs (P-value <0.001).

CONCLUSIONS

CAS represents a safe and effective stroke prevention strategy in high surgical risk patients when compared with CEA. The inconsistent results from the RCTs and the improved outcomes in the prospective clinical trials are likely related to variability in operator experience, use of embolic protection devices, and patient selection strategies.

United Kingdom carotid artery stent registry: short- and long-term outcomes

BACKGROUND

Carotid artery stenting (CAS) has evolved to treat carotid artery disease with the intention of prevent stroke. The British Society of Interventional Radiologists developed a voluntary registry to monitor the practice of this novel procedure. We present the data from the United Kingdom (UK) CAS registry for short and long-term outcomes for symptomatic and asymptomatic carotid disease.

METHODS

The UK CAS registry collected data from 1998 to 2010 from 31 hospitals across the UK for 1,154 patients. All interventions were enrolled in the registry for both asymptomatic and symptomatic patients. Initial entry forms were completed for each patient entered with data including indications, demographic data, CAS data (including stents and protection device details) and 30-day outcomes. Complications were documented. Follow-up data were collected at yearly intervals.

RESULTS

Nine hundred fifty-three (83 %) symptomatic and 201 (17 %) asymptomatic patients were enrolled into the registry. The 30-day all stroke and death rates for symptomatic patients were 5.5 and 2.2 % for those with asymptomatic disease. The 30-day mortality rate was 1.7 % for symptomatic and 0.6 % for asymptomatic patients. For symptomatic patients undergoing CAS, the 7-year all-cause mortality rate was 22.2 % and for asymptomatic patients 18.1 %. The 7-year all-cause mortality and disabling stroke rates were 25.3 and 19.4 %, respectively.

CONCLUSION

These data indicate that outside of the tight constraints of a randomised trial, CAS provides effective prophylaxis against stroke and death.

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.

Stent placement for atherosclerotic stenosis of the vertebral artery ostium: angiographic and clinical outcomes in 117 consecutive patients

BACKGROUND

Although it is thought to be a safe treatment option, the main concerns related to treating vertebral artery ostium (VAO) stenosis with stents have been the rate of restenosis and the uncertain long-term results.

OBJECTIVE

To evaluate the angiographic and clinical results of stent placement for atherosclerotic stenosis of the VAO.

METHODS

One hundred seventeen consecutive patients with atherosclerotic VAO stenosis were treated with stent placement over a period of 12 years. All patients were retrospectively analyzed through the use of a prospectively collected database. The indication criteria for this treatment protocol were symptomatic severe VAO stenoses (> 60%) and asymptomatic severe VAO stenoses (> 60%) with incidentally detected infarction in the posterior circulation. The target diameter of stent dilatation from 1997 to 2000 was the normal vessel diameter just distal to the lesion. Moderate overdilation in the proximal portion of the stents has been performed since 2001.

RESULTS

Successful dilatation was obtained in 116 of 117 cases. Transient neurological complications developed in 2 patients; however, no patients experienced any permanent neurological complications. One hundred four patients underwent follow-up angiography at 6 months after stenting. The restenosis rate at the 6-month follow-up was 9.6% (10 of 104). Until 2000, the restenosis rate after stenting was 13.3%. Since 2001, the restenosis rate has decreased to 4.5%. The median clinical follow-up period was 48 months. The annual rate of strokes in the posterior circulation was 0.95%.

CONCLUSION

Stent placement for atherosclerotic VAO stenosis is considered to be a feasible and safe treatment and may be effective for stroke prevention. The moderate overdilation of stents may be an effective modality for the prevention of restenosis.

Computational modeling of distal protection filters

PURPOSE

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).

METHODS

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.

RESULTS

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.

CONCLUSION

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.

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.

Carotid artery stenting in octogenarians using a proximal endovascular occlusion cerebral protection device: a multicenter registry

BACKGROUND

Carotid stenting (CAS) has been proposed as an alternative to carotid endoarterectomy also in elderly patients with discrepant results. However, the use of proximal neuroprotection devices have not been evaluated in octogenarians.

PURPOSE

The aim of this multicenter prospective registry was to demonstrate that CAS in octogenarians is safe and effective if performed in high-volume centers by experienced operators.

METHODS

From July 2005 to May 2009, a total of 198 octogenarians patients, in three different institutions, were included in this registry. All patients underwent CAS using proximal endovascular occlusion device (Mo.Ma. device Invatec, Roncadelle, Italy). An independent neurologist evaluated all patients. The primary endpoint was death and stroke rate at 30 days.

RESULTS

198 octogenarians (135 men; mean age: 83.2 years) were included in the registry. 39.4% of the patients were symptomatic. Procedural success was 100%. In-hospital complications: Two minor and two major strokes (2.02%) occurred. No device-related complications and no serious access site complication were noted. Between discharge and 30-day follow-up, one patient died due to a cardiac arrest. The overall 30-day combined stroke/death rate was 2.52%, resulting in 1.61% event incidence in asymptomatic and 3.9% in symptomatic patients (P = ns). Logistic regression did not identify independent predictor of neurological events, except in the female gender.

CONCLUSION

This multicenter prospective registry shows that CAS performed with proximal flow blockage is safe and feasible also in octogenarians. Thirty days death/stroke rates are similar to those of the overall population and within the International guidelines.

Multidisciplinary approach to carotid stenting

BACKGROUND

Stroke neurologists, vascular surgeons, interventional neuroradiologists and interventional cardiologists have embraced carotid angioplasty and stenting (CAS) because of potential advantages over carotid endarterectomy (CEA). At Austin Health, a multidisciplinary neuro-interventional group was formed to standardise indications and facilitate training. The aims of this study were to describe our organisational model and to determine whether 30-day complications and early outcomes were similar to those of major trials.

METHODS

A clinical protocol was developed to ensure optimal management. CAS was performed on patients with high medical risk for CEA, with technically difficult anatomy for CEA, or who were randomised to CAS in a trial.

RESULTS

From October 2003 to May 2008, 47 patients (34 male, mean age 71.5) underwent CAS of 50 carotid arteries. Forty-three cases had ipsilateral carotid territory symptoms within the previous 12 months. The main indications for CAS were high risk for CEA (n= 17) and randomised to CAS (n= 21). Interventionists were proctored in 27 cases. The procedural success rate was 94% with two cases abandoned because of anatomical problems and one because of on-table angina. Hypotension requiring vasopressor therapy occurred in 12 cases (24%). The duration of follow up was one to 44 months (mean 6.8 months). The 30-day rate of peri-procedural stroke or death was 6% and the one-year rate of peri-procedural stroke or death or subsequent ipsilateral stroke was 10.6%. Restenosis occurred in 13% (all asymptomatic).

CONCLUSION

A multidisciplinary approach is a useful strategy for initiating and sustaining a CAS programme.

Recurrent subacute in-stent restenosis after carotid artery stenting due to plaque protrusion

A 70-year-old male presented with transient ischemic attacks manifesting as right hemiparesis and motor aphasia due to severe left cervical internal carotid artery stenosis. Carotid artery stenting (CAS) using a flow-reversal system was performed without complications. However, the patient exhibited transient right hemiparesis and motor aphasia 10 days after CAS. Emergent angiography demonstrated in-stent restenosis. In-stent percutaneous transluminal angioplasty and CAS were performed successfully using a distal protection system. However, duplex ultrasound scanning revealed progressive in-stent restenosis, 3 and 6 days after the re-treatment. Emergent angiography again demonstrated in-stent restenosis. Urgent stent removal and carotid endarterectomy were performed. Plaque had prolapsed through the stent. Histological examination revealed that the specimen was mainly plaque consisting of cholesterol crystals and macrophages. The patient was able to return to independent life without neurological deficit. Repeated endovascular surgery with appropriate antiplatelet and anticoagulation therapy should be attempted initially to treat in-stent restenosis. Endarterectomy with stent removal should be considered as a rescue option, especially if plaque protrusion is identified.