Carotid artery stent placement for atherosclerotic disease: rationale, technique, and current status

Acousto-Photolithography for Programmable Shape Deformation of Composite Hydrogel Sheets

Stimuli-responsive hydrogels with programmable shapes produced by defined patterns of particles are of great interest for the fabrication of small-scale soft actuators and robots. Patterning the particles in the hydrogels during fabrication generally requires external magnetic or electric fields, thus limiting the material choice for the particles. Acoustically driven particle manipulation, however, solely depends on the acoustic impedance difference between the particles and the surrounding fluid, making it a more versatile method to spatially control particles. Here, an approach is reported by combining direct acoustic force to align photothermal particles and photolithography to spatially immobilize these alignments within a temperature-responsive poly(N-isopropylacrylamide) hydrogel to trigger shape deformation under temperature change and light exposure. The spatial distribution of particles can be tuned by the power and frequency of the acoustic waves. Specifically, changing the spacing between the particle patterns and position alters the bending curvature and direction of this composite hydrogel sheet, respectively. Moreover, the orientation (i.e., relative angle) of the particle alignments with respect to the long axis of laser-cut hydrogel strips governs the bending behaviors and the subsequent shape deformation by external stimuli. This acousto-photolithography provides a means of spatiotemporal programming of the internal heterogeneity of composite polymeric systems.

Poststent ballooning during transcarotid artery revascularization

BACKGROUND

Poststent ballooning/angioplasty (post-SB) have been shown to increase the risk of stroke risk after transfemoral carotid artery stenting. With the advancement of transcarotid artery revascularization (TCAR) with dynamic cerebral blood flow reversal, we aimed to study the impact of post-SB during TCAR.

METHODS

Patients undergoing TCAR in the Vascular Quality Initiative between September 2016 and May 2019 were included and were divided into three groups: those who received prestent deployment angioplasty only (pre-SB, reference group), those who received poststent deployment ballooning only (post-SB), and those who received both prestent and poststent deployment ballooning (prepost-SB). Patients who did not receive any angioplasty during their procedure (n = 367 [6.7%]) were excluded because these represent a different group of patients with less complex lesions than those requiring angioplasty. Primary outcome was in-hospital stroke or death. Analysis was performed using univariable and multivariable logistic regression models.

RESULTS

Of 5161 patients undergoing TCAR, 34.7% had pre-SB only, 25% had post-SB only, and 40.3% had both (prepost-SB). No differences in the rates of in-hospital and 30-day stroke, death, and stroke/death were observed among the three groups; in-hospital stroke/death in the pre-SB group was 1.4% (n = 25), post-SB 1.2% (n = 16), and prepost-SB 1.4% (n = 29; P = .92). However, patients undergoing post-SB and prepost-SB had higher rates of in-hospital transient ischemic attacks (TIA) (post-SB, 0.9%; prepost-SB, 1% vs pre-SB, 0.2%, P < .01) and postprocedural hypotension (16.6% and 16.8% vs 13.1%, respectively; P < .001). Post-SB also had longer operative times, as well as flow reversal and fluoroscopy times. On multivariable analysis, no association was seen between post-SB and the primary outcome of in-hospital stroke/death (post-SB odds ratio [OR], 0.88; 95% confidence interval [CI], 0.44-1.73; prepost-SB OR, 0.98; 95% CI, 0.57-1.70). Similarly, no significant differences were noted in terms of postprocedural hemodynamic instability and 30-day outcomes. However, post-SB and prepost-SB were associated with four times the odds of in-hospital TIA compared with pre-SB alone (post-SB OR, 4.24 [95% CI, 1.51-11.8]; prepost-SB OR, 4.76 [95% CI, 1.53-14.79]; P = .01). Symptomatic patients had higher rates of in-hospital stroke/death compared with their asymptomatic counterparts; however, there was no significant interaction between symptomatic status and ballooning in predicting the primary outcome.

CONCLUSIONS

Post-SB was used in 65.3% of TCAR patients. This maneuver seems to be safe without an increase in the odds of postoperative in-hospital stroke/death. However, the increased rates of TIA associated with post-SB requires further investigation.

Precautions for using a Filter Protection Device with a Flow Reversal Method during Carotid Artery Stenting: A Case Report on In-Filter Thrombus

The combination of a flow reversal with two balloons and a filter protection device is one of the safest methods that can be used during carotid artery stenting (CAS). Although major adverse events did not occur under restrict protection, we experienced a case of in-filter thrombus during the procedure. A 68-year-old male presented with temporary right hemiparesis. The radiological examinations revealed 95% stenosis on the origin of the left internal carotid artery (ICA). The patient underwent left CAS of wherein a proximal common carotid artery balloon, an external carotid artery balloon, and a distal ICA filter, with continuous flow reversal to the femoral vein, were used. Although the reversal circulation was established, a massive newly developing thrombus was found in the proximal side of the filter. After an additional systemic heparinization, the thrombus disappeared. The procedure was performed without any complications. Physicians should be aware of the risk of developing intraprocedural thrombosis in a filter protection device. Because the filter protection device is designed for the antegrade flow, it may promote the development of thrombus against the retrograde flow. Thus, the filter protection device should be retrieved first under the flow reversal circumstance to avoid the distal migration of a clot around the filter device.

Classification of Carotid Artery Intima Media Thickness Ultrasound Images with Deep Learning

Cerebrovascular accident due to carotid artery disease is the most common cause of death in developed countries following heart disease and cancer. For a reliable early detection of atherosclerosis, Intima Media Thickness (IMT) measurement and classification are important. A new method for decision support purpose for the classification of IMT was proposed in this study. Ultrasound images are used for IMT measurements. Images are classified and evaluated by experts. This is a manual procedure, so it causes subjectivity and variability in the IMT classification. Instead, this article proposes a methodology based on artificial intelligence methods for IMT classification. For this purpose, a deep learning strategy with multiple hidden layers has been developed. In order to create the proposed model, convolutional neural network algorithm, which is frequently used in image classification problems, is used. 501 ultrasound images from 153 patients were used to test the model. The images are classified by two specialists, then the model is trained and tested on the images, and the results are explained. The deep learning model in the study achieved an accuracy of 89.1% in the IMT classification with 89% sensitivity and 88% specificity. Thus, the assessments in this paper have shown that this methodology performs reasonable results for IMT classification.

Crevice sign as an indicator of plaque laceration associated with postoperative severe thromboembolism after carotid artery stenting: a case report

Carotid artery stenting (CAS) is increasingly utilized in patients with carotid artery stenosis. Various intraprocedural and postprocedural complications have been reported in the literature. We present a case of symptomatic major thromboembolism after CAS. The intraprocedural angiogram showed extraordinary slow filling of the contrast medium into the plaque, which we named as "crevice sign." An 83-year-old man presented repeat right amaurosis fugax for 6 months. The radiological examinations revealed 85% stenosis of the origin of the right internal carotid artery. The patient underwent right CAS. The procedure was performed without any problems; however, the angiogram showed slow filling of contrast medium into the carotid plaque through the stent (crevice sign). Sixty minutes later in the ward, the patient presented sudden onset of left hemiparesis and aphasia. Emergency catheter angiography did not show in-stent thrombus, major artery occlusion, or the crevice sign. Magnetic resonance imaging on the next day revealed wide acute infarction of the right cerebral hemisphere. Physicians should be aware of the intraprocedural crevice sign so that a subsequent catastrophic ischemic event can be prevented.

The Feasibility and Safety of Separate Carotid Artery Stenting Using the Restrict Protective Method for Bilateral Carotid Stenosis

BACKGROUND AND OBJECTIVE

The treatment strategy for bilateral carotid stenosis (BCS) is not clear. We report our experience of treating 12 patients with BCS using separate carotid artery stenting (CAS) using the restrict protective method. The order of treatment site and the protective method are also discussed.

METHODS

Between April 2012 and November 2016, 24 lesions in 12 patients (range, 44-83 years; mean, 71 years; 1 woman) underwent CAS at Kariya Toyota General Hospital. These cases were reviewed retrospectively. In all cases, CAS was first performed on the more severely stenosed site. All procedures were performed using the proximal protective method involving balloons and a filter device. We took into consideration adverse events including death from any cause, major stroke within 30 days, and death between 30 days and 1 year later from any stroke.

RESULTS

All procedures were successfully performed under local anesthesia. There was not a single case that showed intolerance during flow arrest to prevent distal embolisms. We observed no adverse events, restenosis, or recurrent symptoms during follow-up.

CONCLUSIONS

Good outcomes can be achieved in patients with BCS when attempting separate CAS using the restrict protective method.

Selective-versus-Standard Poststent Dilation for Carotid Artery Disease: A Systematic Review and Meta-Analysis

BACKROUND

The safety and efficacy of standard poststent angioplasty in patients undergoing carotid artery stent placement have not been well-established.

PURPOSE

We conducted a systematic review of the literature to evaluate the safety and efficacy of carotid artery stent placement and analyzed outcomes of standard-versus-selective poststent angioplasty.

DATA SOURCES

A systematic search of MEDLINE, EMBASE, Scopus, and the Web of Science was performed for studies published between January 2000 and January 2015.

STUDY SELECTION

We included studies with >30 patients describing standard or selective poststent angioplasty during carotid artery stent placement.

DATA ANALYSIS

A random-effects meta-analysis was used to pool the following outcomes: periprocedural stroke/TIA, procedure-related neurologic/cardiovascular morbidity/mortality, bradycardia/hypotension, long-term stroke at last follow-up, long-term primary patency, and technical success.

DATA SYNTHESIS

We included 87 studies with 19,684 patients with 20,378 carotid artery stenoses. There was no difference in clinical (P = .49) or angiographic outcomes (P = .93) in carotid artery stent placement treatment with selective or standard poststent balloon angioplasty. Both selective and standard poststent angioplasty groups had a very high technical success of >98% and a low procedure-related mortality of 0.9%. There were no significant differences between both groups in the incidence of restenosis (P = .93) or procedure-related complications (P = .37).

LIMITATIONS

No comparison to a patient group without poststent dilation could be performed.

CONCLUSIONS

Our meta-analysis demonstrated no significant difference in angiographic and clinical outcomes among series that performed standard poststent angioplasty and those that performed poststent angioplasty in only select patients.

Carotid Artery Dynamics during Head Movements: A Reason for Concern with Regard to Carotid Stenting?

Purpose:

To evaluate carotid artery mobility patterns during head movements following carotid angioplasty/stenting (CAS).

Methods:

In 7 patients (all men; mean age 69 years, range 65–76) who had undergone unilateral CAS, 3D time-of-flight magnetic resonance angiography was performed, visualizing both carotid arteries in 5 different head positions (neutral, turned left and right, and bent forward and backward). Maximum intensity projection reconstructions were obtained to measure angulation at the proximal and distal stent junction. Configuration changes of the stented section of the carotid artery and the unstented contralateral artery were judged. Secondly, transverse sections at the level of the carotid bifurcation and at the skull base were used to calculate torsion shear in the common and internal carotid arteries (CCA, ICA) during turned left and right head position. Results were expressed as median (range).

Results:

In neutral head position, maximal angulation at the distal stent junction was 34.3° (32.3°–55.6°). With the head bent forward, this angulation changed to 47.6° (42.6°–85.2°, p=0.028) and when bent backward to 26.5° (25.0°–48.7°, p=0.027). In all patients, configuration changes of the stented sections were absent. The contralateral unstented side showed diffuse configuration changes without specific angulation at one location. With the head turned left and right, the CCA on the stented side was subjected to 28.6° (13.6°–53.7°) and 24.9° (2.0°–50.6°) of torsion shear, respectively. Torsion of the ICA was subsequently 18.1° (12.7°–40.5°) and 15.2° (2.9°–69.4°).

Conclusions:

Following carotid stenting, sharp ICA angulations that are aggravated by forward bending of the head occur at the distal stent junction. The stented section of the carotid artery shows complete lack of flexibility despite highly flexible features of the stents ex vivo. Both the CCA and ICA are subjected to considerable torsion shear with the head turned left and right. This shear is not accommodated by the current stent designs.

Endovascular Treatment for Extracranial Carotid Stenosis

Introduction:

Bibliometric analysis is a quantitative method that can evaluate publications related to a specific topic.

Methods:

A PubMed database search was conducted from 2003 to 2012 using the search term “carotid” AND “stenos*” as a part of the title or abstract.

Results:

A total of 1590 articles were published in 329 different journals. A total of 751 (47.2%) publications were original articles, 1501 (94.4%) were written in English, 153 (9.6%) received funding, 584 (36.7%) were published by the United States, and 673 (42.3%) resulted from multidisciplinary collaboration. Of the original articles, 538 (71.6%) had retrospective design and 275 (36.6%) had sample size of <50. Vascular surgery departments produced the most articles (n = 339, 21.3%), followed by radiology (n = 270, 17.0%), cardiology (n = 260, 16.4%), neurosurgery (n = 198, 12.5%), and neurology (n = 196, 12.3%). Five major departments published only a small portion (5.1%-26.5%) of articles in their own specialty journals.

Conclusion:

The publication in journals across disciplines and multidisciplinary collaboration are 2 peculiar characteristics of research in this topic.

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.

Early outcomes of carotid artery stenting

BACKGROUND AND AIM

Ischemic cerebrovascular events are the most common reason for patients to be bedridden and the third most common reason for death. Many studies in recent years have demonstrated that carotid artery stenting (CAS) may be an alternative to carotid endarterectomy (CEA). In this study, we aimed to report early outcomes of patients who were treated with CAS in our clinic and discuss practicability, advantages and safety of CAS.

METHODS AND FINDINGS

Eighty patients who underwent CAS between December 2009 and May 2011 were eligible. The mean age was 65 years (range, 49 - 89 years). Of the study group, 73.75% were males and 26.25% were female. The percentage of asymptomatic patients was 11.7%, and the remaining patients were symptomatic. A distal embolic protection device (Angioguard®) was used in 22% of the patients whereas, in the other patients (78%), a proximal blockage system (Mo.MA®) was used. Self-expandable hybrid stents were implanted in all patients and post-dilatation was performed after implantation. None of the patients suffered from stroke, myocardial infarction or death due to CAS during their hospital stay. The mean follow-up period was 10 months (range 2 - 18 months) after discharge. None of the patients had died or had a stroke, a transient ischemic attack (TIA), or a myocardial infarction during the follow-up period. Re-stenosis was not observed in the follow-up carotid Doppler ultrasonography; flow rates were within normal limits.

CONCLUSION

No major complication was observed during the early follow-up period in patients who underwent CAS in our clinic. Only 2 (2.5%) patients showed transient numbness and weakness and these did not lead to morbidity. In the management guide of extracranial carotid and vertebral artery diseases, CAS, in the light of recent studies, is recommended as an alternative to CEA in recommendations for revascularization. One of the important issues emphasized in this guide is the experience of centers. Very low complication rates after CAS suggested that, with suitable patient selection and an experienced team, similar results may be obtained.

Endovascular implantation of covered stents in the extracranial carotid and vertebral arteries: Case series and review of the literature

Background:

Covered stents are used endovascularly to seal arterial wall defects while preserving vessel patency. This report describes our experience with the use of covered stents to treat cervical pathology, and a review of the literature in regards to this topic is presented.

Case Description:

Two patients presenting with the carotid blowout syndrome and one patient with a vertebrojugular fistula were treated with covered stents. This allowed for preservation of the vessel and was a treatment alternative to cerebral bypass.

Conclusion:

Covered stents provide a viable means of preserving the cervical vessels in selected patients; however, long-term follow-up is necessary to determine stent patency and permanency of hemostasis.

Guidelines for the prevention of stroke in patients with stroke or transient ischemic attack: a guideline for healthcare professionals from the american heart association/american stroke association

The aim of this updated statement is to provide comprehensive and timely evidence-based recommendations on the prevention of ischemic stroke among survivors of ischemic stroke or transient ischemic attack. Evidence-based recommendations are included for the control of risk factors, interventional approaches for atherosclerotic disease, antithrombotic treatments for cardioembolism, and the use of antiplatelet agents for noncardioembolic stroke. Further recommendations are provided for the prevention of recurrent stroke in a variety of other specific circumstances, including arterial dissections; patent foramen ovale; hyperhomocysteinemia; hypercoagulable states; sickle cell disease; cerebral venous sinus thrombosis; stroke among women, particularly with regard to pregnancy and the use of postmenopausal hormones; the use of anticoagulation after cerebral hemorrhage; and special approaches to the implementation of guidelines and their use in high-risk populations.

High-resolution CT and angiographic evaluation of NexStent wall adaptation

Carotid stenting is a minimally invasive treatment for extracranial carotid artery stenosis. Stent design may affect technical success and complications in a certain subgroup of patients. We examined the wall adaptability of a new closed-cell carotid stent (NexStent), which has a unique rolled sheet design. Forty-one patients had 42 carotid arteries treated with angioplasty and stenting for internal carotid artery stenosis. The mean patient age was 65 +/- 10 years. All patients underwent high-resolution computed tomographic angiography after the stent implantation. Data analysis included pre- and postprocedural stenosis, procedure complications, plaque calcification, and stent apposition. We reviewed the angiographic and computed tomographic images for plaque coverage and stent expansion. All procedures were technically successful. Mean stenosis was reduced from 84 +/- 8% before the procedure to 15.7 +/- 7% after stenting. Two patients experienced transient ischemic attack; one patient had bradycardia and hypotension. Stent induced kinking was observed in one case. Good plaque coverage and proper overlapping of the rolled sheet was achieved in all cases. There was weak correlation between the residual stenosis and the amount of calcification. The stent provides adequate expansion and adaptation to the tapering anatomy of the bifurcation.

Endovascular treatment of carotid and vertebral pseudoaneurysms with covered stents

BACKGROUND AND PURPOSE

Endovascular treatment of vascular lesions has revolutionized the treatment of arterial pseudoaneurysms. We describe our experience in treating carotid or vertebral pseudoaneurysms with covered stents.

MATERIALS AND METHODS

Ten patients with carotid or vertebral pseudoaneurysms treated with self-expanding or balloon-expandable covered stents were retrospectively reviewed after we obtained institutional review board approval. Distal protection devices were not used. All patients except 1 received anticoagulation therapy. Antiplatelet therapy was used in 8 of 10 patients. Follow-up was performed from 5 days to 25 months. Patients were followed with digital subtraction angiography, CT angiography (CTA), and/or sonography (US).

RESULTS

Pseudoaneurysm occlusion was obtained in all 10 patients. None of the pseudoaneurysms recanalized during the follow-up period. One patient had a distal embolization to the middle cerebral artery despite anticoagulation and antiplatelet therapy. One patient who did not receive any anticoagulation had stent occlusion at 4.5 months. Anticoagulation was stopped after 6 months in 2 patients with persistent stent patency and no neurologic complications for >1 year. Both US and CTA were useful for extracranial stent surveillance. CTA was helpful for intracranial stent surveillance.

CONCLUSION

In this small series, the use of covered stents allowed safe and effective treatment of pseudoaneurysms occurring in the cervical and cephalic segments of the carotid and vertebral arteries.

Efficacy of patient selection strategies for carotid endarterectomy by contrast-enhanced MRA on a 1 T machine and duplex ultrasound in a regional hospital

AIM

To investigate whether contrast-enhanced magnetic resonance angiography (CE-MRA) and duplex ultrasound (DUS) could replace digital subtraction angiography (DSA) for diagnosing internal carotid artery (ICA) stenosis in regional centres with less specialized technicians and equipment, such as a 1 Tesla MRI machine.

MATERIALS AND METHODS

Sixty-six consecutive, symptomatic patients with ICA stenosis, as evidenced using DSA, were included. In the first 34 patients DUS was validated and cut-off criteria were established. Data were analysed by receiver operating characteristic curve and logistic regression. Two observers analysed the DUS and CE-MRA results of 32 patients. Stenoses were categorized in accordance with North American Symptomatic Endarterectomy Trial (NASCET) measurement criteria.

RESULTS

Peak systolic velocity (PSV) in the ICA was defined as a better parameter for defining stenosis than end diastolic velocity and the PSV ICA:common carotid artery ratio. The optimal PSV threshold was 230cm/s. Four ICAs were not interpretable on DUS, and one on CE-MRA. Two patients did not undergo CE-MRA. The sensitivities and specificities were calculated: for DUS these were 100% and 68% respectively; for observer 1 on CE-MRA these were 93% and 89%, respectively; for observer 2 these were 92% and 87%, respectively. The sensitivity and specificity for combined DUS/CE-MRA were 100% and 85%, respectively. Seventy-eight percent of CE-MRA and DUS correlated. The weighted Kappa for CE-MRA and DSA were 0.8 and 0.9, respectively.

CONCLUSION

DUS and CE-MRA are effective non-invasive methods for selecting patients with ICA stenosis for carotid endarterectomy in non-specialized centres using a 1T machine. The present results suggest that no referrals to more specialized centres for non-invasive diagnostic work-up for carotid artery stenoses will be necessary.

Carotid intervention 2: technical considerations

Carotid angioplasty and stenting (CAS) is an evolving technique for treating patients with carotid occlusive disease. However, technical and clinical outcomes are closely related to the knowledge and experience of the interventionalist, and procedural mistakes often lead to serious neurological complications. This article discusses the preinterventional workup of a patient selected for CAS, the different steps of a CAS procedure, the potential complications, how to avoid them, and once they occur how to intervene. Finally, a short overview of the follow-up is given.

Neuropsychological Outcome 6 Months after Unilateral Carotid Stenting

Percutaneous transluminal angioplasty with stenting (PTAS) has become a treatment option for severe carotid stenosis. The goal of our study was to determine prospectively neurocognitive outcome 6 months after unilateral stent-protected carotid angioplasty. Twenty consecutive patients who underwent stent-protected angioplasty for symptomatic (n=9) or asymptomatic (n=11) high-grade carotid stenosis were investigated and compared to an age and disease matched control group. Patients were administered preprocedurally and 6 months postprocedurally a battery of neuropsychological tests. We used reliable change indices methodology in order to control for practice and statistical effects unrelated to intervention. We found no cognitive change in approximately 90% of patients and cognitive improvement in approximately 10% of patients for concentration and attention variables. We further found no cognitive change in 61% of patients, cognitive improvement in 11% of patients and cognitive deterioration in 28% of patients for psychomotor speed. No cognitive change in 94% of patients and cognitive deterioration in 6% of patients was found for sustained attention; no cognitive change in 80% of patients, cognitive improvement in 15% of patients and cognitive deterioration in 5% of patients was found for verbal fluency; no cognitive change in 100% of patients was found for interference (Stroop test): no cognitive change in 95% of patients, cognitive improvement in 5% of patients was found for interference (c.I. test), respectively. Our study showed that 6 months after PTAS cognitive functioning did not change in most patients significantly. For some patients, however, significant improvement or deterioration in single neurocognitive domains can be expected. The reasons for these changes are unclear but may depend on variable type; magnitude of microemboli production; right vs. left cerebral vasculature, respectively.

State of the art: noninvasive imaging and management of neurovascular trauma

Neurotrauma represents a significant public health problem, accounting for a significant proportion of the morbidity and mortality associated with all traumatic injuries. Both blunt and penetrating injuries to cervicocerebral vessels are significant and are likely more common than previously recognized. Imaging of such injuries is an important component in the evaluation of individuals presenting with such potential injuries, made all the more important since many of the vascular injuries are clinically silent. Management of injuries, particularly those caused by blunt trauma, is constantly evolving. This article addresses the current state of imaging and treatment of such injuries.

Reversal of flow during carotid artery stenting: use of the Parodi antiembolism system

INTRODUCTION

To evaluate the flow reversal efficacy of the Parodi antiembolism system (PAES) in the prevention of distal emboli during carotid stenting.

METHODS

A total of 90 patients were treated for internal carotid artery (ICA) stenosis with a stent device. A PAES device was used in 31 symptomatic and 5 asymptomatic patients (total 36 patients) with ICA stenosis, and 54 patients were stented without any protection device. Diffusion-weighted (DW) imaging was performed before and after stenting.

RESULTS

In the group without PAES protection, 23 out of 54 patients showed new lesions on DW images after stenting. Of the lesions seen, 147 (2.72 lesions/patient) were in the vessel-dependent area. In the group with protection, 19 out of 36 patients had new lesions, and only 34 (0.94 lesions/patient) were noted in the vessel-dependent area. The number of new lesions in the nondependent vessel area did not differ if a protection system was used (P = 0.671). The use of PAES led to a significant reduction (P = 0.024) in the incidence of the most frequently seen lesions (size <2 mm). The stroke death rate was 3.3% overall, 3.7% in the group without protection device, and 2.7% in the PAES group. There were no permanent neurological deficits after 3 months.

CONCLUSION

The PAES is a safe and effective tool to reduce the incidence of embolic complications during carotid stenting. Older patients and patients with higher grade stenosis seem to profit more.

Cervical carotid revascularization: the case for carotid angioplasty with stenting

Carotid artery angioplasty with or without stent placement has evolved as an alternative to carotid endarterectomy, particularly for those patients in whom carotid endarterectomy is associated with a higher risk of complications. This article summarizes the selection criteria for participation in and the results of several carotid intervention trials, reviews the relative indications and limitations for both surgical and endovascular revascularization approaches, and describes the technique for and results associated with carotid stenting. The discussion is presented from the vantage of neurosurgeons who are experienced in both revascularization approaches.

Vascular stenting

An explosion of technology has occurred in the last 10 years, intended to make treatment of vascular diseases less invasive. Once the exclusive domain of the interventional cardiologist and the coronary circulation, now in 2001 nearly every vascular system has been explored as a site for endovascular treatment of aneurysmal and atherosclerotic disease. This review will focus on endovascular treatment of abdominal aortic aneurysmal disease and carotid artery disease, and relevant issues for the anesthesiologist encountering these patients and procedures.

Hemodynamic instability after extracranial carotid stenting

OBJECTIVE

Hemodynamic instability (hypertension, hypotension and bradycardia) is a well-known complication of carotid endarterectomy. Carotid angioplasty and stenting (CAS) is becoming a valuable alternative treatment for patients with severe carotid stenosis and increased surgical risk. CAS implies instrumentation of the carotid bulb, so baroceptor dysfunction may provoke hemodynamic instability. The aim of this work was to calculate the incidence of this complication and to detect factors to predict it.

METHODS

Medical records and angiograms of 51 consecutive patients submitted to CAS for severe atherosclerotic stenosis (40 cases) or postsurgical restenosis (11 cases) were retrospectively reviewed in order to detect the occurrence of intra- and post-procedural hypertension (systolic blood pressure >160 mmHg), hypotension (systolic blood pressure <90 mmHg) and bradycardia (heart rate <60 beats/min). The relationship between clinical, procedural and angiographic factors and the occurrence of hemodynamic instability was assessed with univariate and multivariate analysis (logistic regression).

RESULTS

Transient mild systolic post-procedural hypertension occurred in five cases (10%); preprocedural hypertension, asymptomatic stenosis and ipsilateral post-surgical restenosis predicted this. Hypotension with bradycardia also occurred in five cases (10%), one with neurological sequelae. Transient periprocedural bradycardia occurred in 19 cases (37%). Severe bradycardia without hypotension arose in one case only. Factors predicting post-procedural hypotension included the presence of a fibrous plaque and the ratio between the pre- and post-stenting diameter of the internal carotid artery. Peri-procedural bradycardia predicted post-procedural bradycardia. None of these factors were confirmed by multivariate analysis as a significant prognostic predictor.

CONCLUSION

Mild systolic hypertension may occur after CAS, but is resolved by medical treatment. Prolonged hypotension and bradycardia may also arise and this can be dangerous because it may cause neurological deterioration due to hypoperfusion. These complications cannot be predicted by clinical, procedural, and angiographic factors.

Complications and Follow-up after Unprotected Carotid Artery Stenting

PURPOSE

This prospective study was undertaken to determine the success rate, complications, and outcome of carotid artery stenting (CAS) without the use of cerebral protection devices.

METHODS

During 12 months, 94 high-grade stenoses of the carotid artery in 91 consecutive patients were treated. Sixty-six (70%) of the stenoses were symptomatic and 28 (30%) were asymptomatic.

RESULTS

In all 94 carotid stenoses CAS was successfully performed. During the procedure and within the 30 days afterwards, there were 2 deaths and 3 major strokes in the 66 symptomatic patients, resulting in a combined death and stroke rate of 5 of 66 (7%). Only one of these complications, a major stroke, occurred during the procedure. In the 6-month follow-up, one additional major stroke occurred in a originally symptomatic patient resulting in a combined death and stroke rate of 6 of 66 (10%) for symptomatic patients at 6 months. No major complications occurred in asymptomatic patients during the procedure or in the 6-month follow-up period. At 6 months angiographic follow-up the restenosis rate with a degree of >50% was 3 of 49 (6%) and the rate with a degree of >or=70% was 1 of 49 (2%).

CONCLUSIONS

Cerebral embolization during CAS is not the only cause of the stroke and death rate associated with the procedure. The use of cerebral protection devices during the procedure may therefore not prevent all major complications following CAS.

Carotid artery stenting in surgical high-risk patients

Recent studies have shown that carotid artery angioplasty and stenting may offer a viable alternative for symptomatic and asymptomatic patients with carotid artery stenosis, especially in high-risk patients. We report the results of a prospective single-center registry designed to evaluate the feasibility and safety of carotid artery angioplasty and stenting with and without distal protection devices in high-risk patients. A total of 116 consecutive patients underwent 126 procedures and 127 stents were deployed successfully in 130 lesions. The majority of patients (63%) had restenosis after a prior carotid endarterectomy; 31% were considered to be ineligible for carotid endarterectomy by both the vascular surgeons and the interventional cardiologist and 9% were considered ineligible for surgery due to hostile neck anatomy. Periprocedural and follow-up evaluation included a thorough independent clinical and neurological assessment. Distal embolic protection devices were used in 44% of all cases. Procedural success was achieved in 122 procedures (97%). The overall rate of in-hospital major adverse cerebrovascular events (death, stroke, and myocardial infarction) was 2.6%. Event rates in patients with prior carotid endarterectomy were comparable to patients with de novo lesions with 5.2% vs. 2.4% death/stroke at 30 days and 8.3% and 6.6% stroke/death rates at 1 year, respectively. When distal protection devices were used, death/stroke rates were 0% as compared to 4.5% when distal protection was not used (P = NS). However, minor embolic phenomena were observed in both primary and secondary lesions independent of the use of distal protection. These results support the use of carotid artery angioplasty and stenting in high-risk patients with significant primary or secondary carotid artery stenosis. In both types of lesions, acceptable results justify its use as a valid revascularization method. While clinical embolic events occur in a minority of patients in both lesion types, they are not entirely prevented by distal protection.

Passive catheter visualization in magnetic resonance–guided endovascular therapy using multicycle projection dephasers

PURPOSE

To improve upon the conventional projection dephaser (PD) method of background suppression and evaluate the use of multicycle projection dephasers to improve catheter conspicuity in background-suppressed MR images.

MATERIALS AND METHODS

Passive visualization of endovascular catheters in MR images is compared using two background suppression techniques: 1) the conventional PD method and 2) the multicycle PD method. Contrast-filled 4-French (1.3 mm) catheters were imaged in homogeneous and heterogeneous phantoms, and in the common carotid artery of a canine using a modified spoiled gradient echo imaging sequence. We used catheter-to-background contrast (ranging from -100% to 100%) as the metric to compare background suppression techniques.

RESULTS

In the homogeneous and heterogeneous phantoms, the contrast was -6.9% (catheter darker than background) and 15.0%, respectively, using the conventional PD method, and 50.6% and 44.0%, respectively, using the multicycle PD method. In the canine carotid artery, the contrast was -3.1% using the conventional PD method and 53.0% using the multicycle PD method.

CONCLUSION

This work shows that multicycle projection dephasers improve catheter conspicuity over the conventional PD method. The multicycle PD method has potential for use in guiding endovascular procedures.

Assessment of short-term outcomes for protected carotid angioplasty with stents using recent evidence

BACKGROUND

Carotid artery stenosis is an important risk factor and etiology of stroke. Carotid endarterectomy (CEA) is the gold standard for the treatment of carotid artery stenosis; however, there are potential benefits to adopting the use of carotid artery stenting (CAS) with protection devices. A number of large protected CAS (PCAS) trials are underway, but final results are still several years away. In the interim, numerous PCAS studies have recently been published, and the aim of this study was to combine the published results and examine the outcomes and safety of PCAS.

METHODS

Electronic, manual, and bibliographic searches of PubMed and PreMedline were conducted. Proportion differences were calculated for the periprocedural (30-day) outcomes of any stroke and any stroke or death.

RESULTS

More than 400 articles were identified. Only 26 studies met the inclusion criteria, resulting in the inclusion of 2,992 patients treated with PCAS. Within this patient group, the pooled perioperative PCAS rate of any type of stroke was 2.4% +/- 0.3% (95% confidence interval [CI]). The 30-day minor stroke rate was 1.1% +/- 0.2% (95% CI), and the 30-day major stroke rate was 0.6% +/- 0.2% (95% CI). The 30-day mortality rate was 0.9% +/- 0.4% (95% CI).

CONCLUSION

This study demonstrates relatively low rates of reported perioperative adverse events in PCAS. Selective use of PCAS to treat carotid artery stenosis in those at highest risk for surgical complications is appropriate until the randomized trials of CEA vs PCAS provide concurrent short- and long-term outcome data.

Protected stent-assisted angioplasty in radiation-induced carotid artery stenosis

OBJECTIVE

The surgical treatment of radiation-induced carotid stenosis is challenging and presents a high rate of complications. This has led several investigators to propose stent-assisted angioplasty as the treatment of choice for this condition. The aim of this study is to evaluate the potential risks of intra-procedural embolic stroke in this setting using cerebral protection devices.

METHODS

We describe our recent experience in the endovascular treatment by means of stent-assisted angioplasty with the aid of a filter cerebral protection device of eight patients presenting with radiation-induced carotid stenosis.

RESULTS

Procedural success, defined as residual stenosis of less than 30% was obtained in all cases. The mean percentage stenosis was reduced from mean 80+/-6.3% (range 70-90%) to 13+/-4% (range 10-20%). Predilation was performed in five cases, post-dilation in all the cases. Mild-to-moderate bradycardia while inflating the balloon was present in three cases and was severe in one case. No patient sustained myocardial infarction, stroke or TIA during the procedure or hospital stay. During a mean clinical follow-up of 16+/-7.3 months (range 5-25) there were no neurological events. On sonographic follow-up, no patient presented in-stent de novo stenosis.

DISCUSSION

Carotid angioplasty with cerebral protection can be performed safely in radiation-induced carotid stenosis with a high technical success rate. With the recent innovations and improvements in angioplasty technique, its indications and results will have to be redefined. Given the complexity and complications of surgical approaches for this condition, and the encouraging results obtained with endovascular techniques, carotid angioplasty emerges as the preferred treatment option.

Protected stent-assisted carotid angioplasty in the management of late post-endarterectomy restenosis

OBJECTIVES

The high complication rate associated with the surgical treatment of post-carotid endarterectomy restenosis has led several investigators to propose stent-assisted angioplasty as the treatment of choice for this condition. Late restenosis is very infrequent and mainly due to atherosclerotic progression. The aim of this study is to evaluate the potential risk of intraprocedural embolic stroke during stent-assisted angioplasty with cerebral protection devices in these patients.

METHODS

We describe our recent experience in the endovascular treatment of 10 patients presenting late carotid restenosis by means of stent-assisted angioplasty with the aid of a filter cerebral protection device. Mean elapsed time from surgery to angioplasty was 92+/-31 months (range 48-144 months).

RESULTS

Procedural success was obtained in all the cases. Pre-dilation was performed in six cases, post-dilation in all the cases. The mean percentage stenosis was reduced from mean 77+/-12% (range 60-95%) to 6.3+/-6.7% (range 0-17%). Bradycardia while inflating the balloon was mild-to-moderate in seven cases and severe in two. No patient sustained stroke or transient ischemic attack (TIA) during the procedure or during hospital stay. On follow-up, two patients presented with moderate asymptomatic restenosis and were managed conservatively.

DISCUSSION

Carotid angioplasty with cerebral protection can be performed safely in late carotid restenosis with a high technical success rate. No clinical embolic complications occurred in this subset of patients. With recent innovations and improvements in angioplasty technique, previous indications for angioplasty in these patients will have to be redefined. Carotid angioplasty seems to be a valuable treatment alternative to conventional surgery in this subset of patients.

Cerebral revascularization by endovascular techniques

The minimally invasive approach to managing patients with ischemic and hemorrhagic stroke by endovascular intervention has made tremendous progress over the past years. Early recognition of stroke, improved ability to accurately diagnose the site of pathological abnormality with advanced imaging techniques and advances in treatment alternatives have led to better patient outcomes. Endovascular techniques for cerebral revascularization, a leading new therapeutic approach in the treatment of cerebrovascular disease, play a major role in both the management of acute stroke and secondary prevention. Selective intra-arterial thrombolysis for acute stroke has been performed for more than two decades with increasing success. Neurovascular therapies for secondary prevention include angioplasty of extracranial and intracranial vessels, as well as procedures for arterial reconstruction.

Risk factors for periprocedural complications in carotid artery stenting without filter protection

INTRODUCTION

In high-grade stenosis, carotid artery stenting (CAS) may be chosen as an alternative to carotid surgery. Ischemic periprocedural complications may be documented best with diffusion-weighted MRI (DWMRI). In this prospective study serial DW-MRI and color-coded duplex sonography (CCDS) were used to identify carotid stenosis, which is associated with an increased risk of ischemic events due to CAS.

METHODS

High resolution DW-MRI were performed in 74 out of 77 patients before and after CAS. All MRI scans were analyzed in a blinded manner. With CCDS each carotid stenosis was evaluated according to the grade, length, echo properties and plaque surface.

RESULTS

In 42 out of 74 patients (56.8 %) a total of 188 new procedure- related DWI-lesions could be detected, while in 32 patients MRI-controls remained normal. Of the lesions 79.25 % had a size < 1 cm. In one major and two minor strokes due to CAS (total complication rate 3.9 %) corresponding territorial infarcts could be demonstrated. A highly significant correlation was found between the length of the stenosis and the incidence of new DWI-lesions (p = 0.0141). In contrast, neither the grade of ICA stenosis nor the sonographic plaque morphology or plaque surface correlated with the number of DWI-lesion in postinterventional scans.

CONCLUSIONS

The length-and not the degree-of an ICA stenosis seems to be the most decisive sonographic factor for estimating the periprocedural risk of embolism. DWI-lesions are much more frequent than clinical complications and may represent an important surrogate marker for improving the techniques of carotid artery stenting, especially comparing the benefit of different mechanical protection devices.

Concurrent coronary and carotid artery surgery: factors influencing perioperative outcome and long-term results†

AIMS

To assess risk factors for early and late outcome after concurrent carotid endarterectomy (CEA) and coronary artery bypass grafting (CABG).

METHODS AND RESULTS

Records of all 311 consecutive patients having concurrent CEA and CABG from 1989 to 2002 were reviewed, and follow-up obtained (100% complete). In the group (mean age 67 years; 74% males), 62% had triple-vessel disease, 57% unstable angina, 31% left main coronary stenosis, 19% congestive heart failure, and 35% either a history of vascular procedures or existing vasculopathies. Preoperative assessment revealed transient ischaemic attack in 16%, stroke in 7%, and bilateral carotid disease in 20%. There were 7% emergent and 19% urgent operations, and ascending aorta was described as atheromatous or calcified in 21%. Hospital death occurred in 19 patients, myocardial infarction in seven, and permanent stroke in 12. Significant multivariable predictors of hospital death were aortic calcifications, coexisting vasculopathy, and emergent procedure. Significant predictors of postoperative stroke were calcified or dilated aorta, and of prolonged hospital stay were advanced age, unstable angina, and coexisting vascular disease. For hospital survivors, 10-year actuarial late event-free rates were: death, 50%; myocardial infarction, 84%; stroke, 93%; percutaneous angioplasty, 95%; redo CABG, 98%; and all morbidity and mortality, 48%. Significant multivariable predictors of late deaths were coexisting vasculopathy, age, renal insufficiency, previous cardiac surgery, tobacco abuse, calcified or atheromatous aorta, and duration of intensive care unit stay.

CONCLUSION

Concurrent CEA and CABG can be performed with acceptable operative mortality and morbidity, and good long-term freedom from coronary and neurologic events. Atheromatous aortic disease is a harbinger of poor operative and long-term outcome.

Recommendations for Comprehensive Stroke Centers

Background and Purpose— To develop recommendations for the establishment of comprehensive stroke centers capable of delivering the full spectrum of care to seriously ill patients with stroke and cerebrovascular disease. Recommendations were developed by members of the Brain Attack Coalition (BAC), which is a multidisciplinary group of members from major professional organizations involved with the care of patients with stroke and cerebrovascular disease.

Summary of Review— A comprehensive literature search was conducted from 1966 through December 2004 using Medline and Pub Med. Articles with information about clinical trials, meta-analyses, care guidelines, scientific guidelines, and other relevant clinical and research reports were examined and graded using established evidence-based medicine approaches for therapeutic and diagnostic modalities. Evidence was also obtained from a questionnaire survey sent to leaders in cerebrovascular disease. Members of BAC reviewed literature related to their field and graded the scientific evidence on the various diagnostic and treatment modalities for stroke. Input was obtained from the organizations represented by BAC. BAC met on several occasions to review each specific recommendation and reach a consensus about its importance in light of other medical, logistical, and financial factors.

Conclusions— There are a number of key areas supported by evidence-based medicine that are important for a comprehensive stroke center and its ability to deliver the wide variety of specialized care needed by patients with serious cerebrovascular disease. These areas include: (1) health care personnel with specific expertise in a number of disciplines, including neurosurgery and vascular neurology; (2) advanced neuroimaging capabilities such as MRI and various types of cerebral angiography; (3) surgical and endovascular techniques, including clipping and coiling of intracranial aneurysms, carotid endarterectomy, and intra-arterial thrombolytic therapy; and (4) other specific infrastructure and programmatic elements such as an intensive care unit and a stroke registry. Integration of these elements into a coordinated hospital-based program or system is likely to improve outcomes of patients with strokes and complex cerebrovascular disease who require the services of a comprehensive stroke center.

Carotid endarterectomy remains the standard of care, even in high-risk surgical patients

OBJECTIVE

This study tested the hypothesis that high-risk patients can undergo carotid endarterectomy without associated increased risk of stroke, transient ischemic attack (TIA), or death.

SUMMARY BACKGROUND DATA

Carotid endarterectomy (CEA) has clearly been shown to be effective in reducing the risk of stroke in selected symptomatic and asymptomatic patients with extracranial carotid stenosis. However, recently, carotid angioplasty with stenting (CAS) has been suggested as an alternative treatment in high-risk surgical patients.

METHODS

Medical records for consecutive patients who underwent CEA from 1996 to 2001 were reviewed for demographics, medical history, and hospital course. High-risk patients were defined as those experiencing a myocardial infarction (MI) or an exacerbation of congestive heart failure (CHF) within 4 weeks before CEA; unstable angina; steroid-dependent chronic obstructive pulmonary disease (COPD); prior ipsilateral CEA, neck dissection or irradiation; high carotid bifurcation; and those with combined cardiac-carotid procedures. Poor postoperative outcome was defined as stroke, TIA, or death within 30 days. Univariate, multivariate, and Kaplan-Meier analysis were used as appropriate.

RESULTS

Four hundred twenty-nine patients underwent 499 CEAs, of which 84 (17%) were considered high risk. The overall stroke-death rate among all patients was 2.8%. A total of 11 postoperative strokes (2.2%), 7 TIAs (1.4%), and 3 deaths (0.6%) occurred within 30 days after surgery. There was no difference in 30-day poor outcome between high- and low-risk patients (4.8% vs. 4.1%, P = 0.77). When these risk factors were assessed independently, those with recent MI were at higher risk for poor outcome (odds ratio [OR], 13.3; 95% confidence interval [CI], 2.2-82.0; P = 0.03). Multivariate analysis also revealed that a history of contralateral stroke or TIA conferred an increased risk of poor outcome (OR, 3.0; 95% CI, 1.1-8.4; P = 0.02), whereas use of preoperative angiotensin-converting enzyme inhibitors was associated with reduced risk (OR, 0.36; 95% CI, 0.11-1.0; P = 0.05), as was a history of hyperlipidemia (OR, 0.33; 95% CI, 0.13-0.87; P = 0.03). By log-rank analysis, 12-month survival was significantly worse in the high-risk group as compared with the low-risk (96% vs. 91%, P = 0.03).

CONCLUSIONS

Patients considered a surgical high risk can undergo CEA without any worse outcome compared with those patients deemed low risk. The benefit of CAS will likely be marginal, and only controlled clinical trials will be able to determine if certain subgroups demonstrate improved outcome with CAS. Carotid endarterectomy remains the standard of care, even in high-risk surgical patients.

Proximale Protektionssysteme beim Karotisstent

Controversies as to whether or not a protection device should be used in carotid artery stenting exist. Currently three temporary cerebral protection devices are being used. These are devices with distal balloon occlusion or filtration baskets and proximal occlusion devices with flow reversal in the internal carotid artery. This article focuses on flow reversal systems and aims to give some advice as to which patients could benefit from their use.

[Gadolinium-medium filter-protected percutaneous stended carotid angioplasty]

We report on a patient who underwent a percutaneous carotid angioplasty with stenting. The procedure was protected by a filter and used gadolinium instead of iodine. No neurological or renal complication occurred. This observation represents one of the first publications describing the use of this contrast medium in a complex neuroradiological intervention.

Extracranial revascularization therapy: Angioplasty and stenting

Beginning with simple balloon angioplasty, minimally invasive revascularization techniques have progressed to the use of metallic stents for improved immediate and long-term results. Stent-supported angioplasty now offers a therapeutic option for those individuals ineligible for surgical revascularization of stenotic atherosclerotic lesions and who have failed maximal medical therapy. However, the clinical equivalence, or possibly even superiority, of angioplasty of the extracranial carotid and vertebral arteries in atheromatous occlusive disease over surgical revascularization has yet to be determined in ongoing randomized controlled trials. Additionally, endovascular techniques offer treatment for a variety of nonatherosclerotic disease affecting the extracranial arteries, such as inflammatory, radiation-induced, and postsurgical strictures; acute intimal dissection; traumatic and spontaneous arteriovenous fistulas; and aneurysms or pseudoaneurysms. For certain disease entities at high risk for surgical complications, endovascular procedures have gained preference as the therapeutic modality of choice, yet lacking controlled trials providing evidence for noninferiority against surgical approach. Continued innovation and refinement of endovascular technology and techniques will further improve technical success, reduce procedure-related morbidity, and broaden the endovascular therapeutic spectrum for extracranial and intracranial cerebrovascular disease.

Feasibility of simultaneous bilateral carotid artery stenting

Due to the progressive aging of the population, severe bilateral carotid stenosis has become a more frequent condition. On occasion, simultaneous revascularization may be appropriate. There is increased evidence that for these high-risk patients, a percutaneous revascularization may be the best approach. However, there are concerns that simultaneous bilateral carotid stenting may be associated with cerebral hyperperfusion, excessive bradycardia, and hypotension. We report a series of 10 consecutive patients who underwent simultaneous bilateral carotid stenting. All of these patients were not deemed to be surgical candidates due to high-risk comorbidities. All but one of the lesions were successfully stented. There were no procedural deaths, myocardial infarctions, or strokes. Thus, among carefully selected patients, simultaneous bilateral carotid artery stenting is a promising, technically feasible option.

Lumbosacral radiculopathy following radiofrequency ablation therapy

Radiofrequency ablation (RFA) is a treatment modality for several types of malignancies and vascular malformations. Only limited information is available on neurologic complications following RFA. We report three cases of acute lumbosacral radiculopathy after abdominal RFA, in two of which electrophysiologic studies were performed. All three patients had significant spontaneous clinical improvement. We suggest the underlying cause was partial axonopathy due to thermal injury, but with a good prognosis.