Frequency and management of recurrent stenosis after carotid artery stent implantation

Cutting Balloon Angioplasty for Severe In-Stent Restenosis after Carotid Artery Stenting: Long-Term Outcomes and Review of Literature

PURPOSE

Cutting balloon-percutaneous transluminal angioplasty (CB-PTA) is a feasible treatment option for in-stent restenosis (ISR) after carotid artery stenting (CAS). However, the longterm durability and safety of CB-PTA for ISR after CAS have not been well established.

MATERIALS AND METHODS

We retrospectively reviewed medical records of patients with ISR after CAS who had been treated with CB-PTA from 2012 to 2021 in our center. Detailed information of baseline characteristics, periprocedural and long-term outcomes, and follow-up imaging was collected.

RESULTS

During 2012-2021, a total of 301 patients underwent CAS. Of which, CB-PTA was performed on 20 lesions exhibiting severe ISR in 18 patients following CAS. No patient had any history of receiving carotid endarterectomy or radiation therapy. These lesions were located at the cervical segment of the internal carotid artery (n=16), proximal external carotid artery (n=1), and distal common carotid artery (n=1). The median time interval between initial CAS and detection of ISR was 390 days (interquartile range 324-666 days). The follow-up period ranged from 9 months to 9 years with a median value of 21 months. Four patients (22.2%) were symptomatic. The average of stenotic degree before and after the procedure was 79.2% and 34.7%, respectively. Out of the 18 patients receiving CB-PTA, 16 (88.9%) did not require additional stenting, and 16 (88.9%) did not experience recurrent ISR during the follow-up period. Two patients who experienced recurrent ISR were successfully treated with CB-PTA and additional stenting. No periprocedural complication was observed in any case.

CONCLUSION

Regarding favorable periprocedural and long-term outcomes in our single-center experience, CB-PTA was a feasible and safe option for the treatment of severe ISR after CAS.

Comparison of Restenosis Risk in Single-Layer versus Dual-Layer Carotid Stents: A Duplex Ultrasound Evaluation

PURPOSE

The aim of this study was to report intermediate-term results of duplex ultrasound follow-up of carotid artery stenting performed with the dual-layer stent as compared to concurrent patients treated with other commercially available single-layer carotid stents.

MATERIALS AND METHODS

A single centre, retrospective, nonrandomized study including 162 non-consecutive patients with 199 implanted carotid stents treated over a 7-year period was conducted. Patients with at least one ultrasound examination after treatment were included. Procedural and follow-up data for patients treated with the dual-layer stent implantation (83 stents) vs first-generation carotid stents implantations (116 stents) were compared.

RESULTS

The median follow-up time was 24.0 months (IQR 10-32 months) for dual-layer stents and 27.5 months (IQR 10.3-59 months) for single-layer stents. The rate of severe restenosis was significantly higher in the dual-layer stent group than in the single-layer group (13.3% [11/83] vs 3.4% [4/116], p = 0.01). Seven reinterventions were performed in 5 patients with dual-layer stents. The rate of reintervention was significantly higher compared to no reinterventions in single-layer stents (6% [5/83] vs 0% [0/116], p = 0.012). Patients with restenosis had significantly higher presence of dyslipidaemia (100% [12/12] vs 63.3% [95/150], p = 0.009).

CONCLUSIONS

In this real-world cohort of patients undergoing carotid artery stenting, the patients treated with low-profile dual-layer micromesh stent showed higher rates of restenosis and reinterventions compared to first-generation single-layer stents.

Treatment of the Carotid In-stent Restenosis: A Systematic Review

Background and Purpose: In-stent restenosis (ISR) after carotid artery stent (CAS) is not uncommon. We aimed to evaluate therapeutic options for ISR after CAS. Methods: We searched PubMed and EMBASE until November 2, 2020 for studies including the treatment for ISR after CAS. Results: In total, 35 studies, covering 1,374 procedures in 1,359 patients, were included in this review. Most cases (66.3%) were treated with repeat CAS (rCAS), followed by percutaneous transluminal angioplasty (PTA) (17.5%), carotid endarterectomy (CEA) (14.3%), carotid artery bypass (1.5%), and external beam radiotherapy (0.4%). The rates of stroke & TIA within the postoperative period were similar in three groups (PTA 1.1%, rCAS 1.1%, CEA 1.5%). CEA (2.5%) was associated with a slightly higher rate of postoperative death than rCAS (0.7%, P = 0.046). Furthermore, the rate of long-term stroke & TIA in PTA was 5.7%, significantly higher than rCAS (1.8%, P = 0.036). PTA (27.8%) was also associated with a significantly higher recurrent restenosis rate than rCAS (8.2%, P = 0.002) and CEA (1.6%, P < 0.001). The long-term stroke & TIA and recurrent restenosis rates showed no significant difference between rCAS and CEA. Conclusions: rCAS is the most common treatment for ISR, with low postoperative risk and low long-term risk. CEA is an important alternative for rCAS. PTA may be less recommended due to the relatively high long-term risks of stroke & TIA and recurrent restenosis.

Carotid Endarterectomy with Stent Graft Removal and End to End Bypass in the Treatment of In-Stent Occlusion after Endovascular Therapy of Carotid Gunshot Injury

Carotid jugular fistula and pseudoaneurysm are easy to form after gunshot injury of carotid artery. Endovascular therapy, such as stent graft implantation, can successfully block the fistula and pseudoaneurysm cavity. However, the possibility of in-stent restenosis or occlusion will lead to treatment failure. The authors describe the case of a 30-year-old man with carotid jugular fistula and pseudoaneurysm after gunshot injury of left carotid artery who had received stent graft placement. However, two years after stent graft, the stenosis of proximal carotid artery near stent was found and gradually aggravated. During the follow-up, transient amaurosis of his left eye occurred intermittently and in-stent occlusion and severe stenosis of proximal carotid artery were found by computed tomography angiography (CTA) in our center. Carotid endarterectomy (CEA)with stent graft removal and end to end bypass using vascular graft was performed to reconstruct the blood flow of left carotid artery. To the extent of the authors' knowledge, this case illustrates a rare CEA and vascular graft bypass in the treatment of in-stent occlusion following the gunshot injury to the carotid artery. The successful treatment of this rare case provides an option to deal with this kind of tricky problem.

The management of carotid restenosis: a comprehensive review

Carotid artery stenosis (CS) is a major medical problem affecting approximately 10% of the general population 80 years or older and causes stroke in approximately 10% of all ischemic events. In patients with symptomatic, moderate-to-severe CS, carotid endarterectomy (CEA) and carotid angioplasty and stenting (CAS), has been used to lower the risk of stroke. In primary CS, CEA was found to be superior to best medical therapy (BMT) according to 3 large randomized controlled trials (RCT). Following CEA and CAS, restenosis remains an unsolved problem involving a large number of patients as the current treatment recommendations are not as clear as those for primary stenosis. Several studies have evaluated the risk of restenosis, reporting an incidence ranging from 5% to 22% after CEA and an in-stent restenosis (ISR) rate ranging from 2.7% to 33%. Treatment and optimal management of this disease process, however, is a matter of ongoing debate, and, given the dearth of level 1evidence for the management of these conditions, the relevant guidelines lack clarity. Moreover, the incidence rates of stroke and complications in patients with carotid stenosis are derived from studies that did not use contemporary techniques and materials. Rapidly changing guidelines, updated techniques, and materials, and modern medical treatments make actual incidence rates barely comparable to previous ones. For these reasons, RCTs are critical for determining whether these patients should be treated with more aggressive treatments additional to BMT and identifying those patients indicated for surgical or endovascular treatments. This review summarizes the current evidence and controversies concerning the risks, causes, current treatment options, and prognoses in patients with restenosis after CEA or CAS.

A Review on the Comparison of Different Treatments for Carotid In-Stent Restenosis

Different treatment options for carotid in-stent restenosis (ISR) have been reported with good outcome, including carotid endarterectomy (CEA), repeated carotid angioplasty stenting (CAS) and percutaneous transluminal angioplasty (PTA) with drug-coated balloons (DCBs). However, the optimal treatment option for ISR has not yet been determined. A systematic literature search was performed in the databases of Medline, Embase, Cochrane library, and unpublished data from clinicaltrials.gov from 1990 to March 1, 2019. Studies were enrolled if they reported treatment strategies for carotid ISR treatment and met the inclusion criteria. After study inclusions, data were extracted and summarized. Totally 25 cross-sectional studies were included, containing 5 comparative studies, 16 studies using repeated PTA, and 4 studies adopting CEA treatment. Our study summarized the current available data, showing that all the studies could effectively relieve the carotid ISR by significantly improving the angiographic stenosis and decreasing the peak systolic velocity values. Meanwhile, CEA treatment had the best long-term effects in relieving restenosis, while re-PTA with stenting/balloon angioplasty had a certain rate of restenosis, ranging from 33% to 83%. Furthermore, re-PTA/stenting and balloon angioplasty treatment had less complications compared with CEA. Also, we analyzed the risk factors that might affect the long-term prognosis of carotid ISR patients. The therapeutic measures for carotid ISR had their own features, with CEA had the highest efficacy while re-PTA/stenting and balloon angioplasty were with less complications. More large-scale comparative clinical studies are needed to further ascertain the best strategies.

Restenosis after carotid artery stenting

As a common etiology for ischemic stroke, atherosclerotic carotid stenosis has been targeted by vascular surgery since 1950s. Compared with carotid endarterectomy, carotid angioplasty and stenting (CAS) is almost similarly efficacious and less invasive. These advantages make CAS an alternative in treating carotid stenosis. However, accumulative evidences suggested that the long-term benefit-risk ratio of CAS may be decreased or even neutralized by the complications related to in-stent restenosis (ISR). Therefore, investigating the mechanisms and identifying the influential factors of ISR are of vital importance for improving the long-term outcomes of CAS. As responses to intrinsic and extrinsic injuries, intimal hyperplasia and vascular smooth muscle cell proliferation have been regarded as the principle mechanisms for ISR development. Due to the lack of consensus-based definition and consistent follow-up protocol, the reported incidences of ISR after CAS varied widely among studies. These variations made the inter-study comparisons of ISR largely illogical. To eliminate restenosis after CAS, both surgery and endovascular procedures have been attempted with promising results. For preventing ISR, drug-eluting stents and antiplatelets have been proposed as potential solutions.

Neurosonology and noninvasive imaging of the carotid arteries

In this chapter, we review imaging of the extracranial carotid arteries and the indications for noninvasive carotid artery evaluation, measuring the degree of arterial stenosis and plaque morphology. We also analyze the types of noninvasive imaging, including carotid duplex ultrasound, transcranial Doppler, magnetic resonance angiography, and computer tomography angiography. We look at each of these modalities, briefly discussing techniques, benefits, limitations, and sources of error. Furthermore, we discuss the apparent accuracy and the need for multimodality imaging. Finally, an imaging algorithm for the evaluation of the extracranial carotid arteries is proposed, which is in routine use at our hospital.

The myth of restenosis after carotid angioplasty and stenting

BACKGROUND AND PURPOSE

Reported rates of in-stent restenosis after carotid artery stenting (CAS) vary, and restenosis risk factors are poorly understood. We evaluated restenosis rates and risk factors, and compared patients with 'hostile-neck' carotids (a history of ipsilateral neck surgery or irradiation) and atherosclerotic lesions.

METHODS

Demographic, clinical, and radiological characteristics of patients undergoing cervical CAS between 1995 and 2010 with at least 1 month of follow-up were reviewed. Patients with substantial (≥50%) radiographic restenosis were compared with those without significant restenosis to identify restenosis risk factors.

RESULTS

The analysis included 121 patients with 133 stented vessels; 91 (68.4%) lesions were symptomatic. Indications for stent placement included hostile-neck lesions, substantial surgical comorbidities, inclusion in a randomized carotid stenting trial, acute carotid occlusion, tandem stenosis, large pseudoaneurysm, high carotid bifurcation, and contralateral laryngeal nerve palsy. Procedures were technically successful in all but one lesion (99.2%). Perioperative stroke occurred in four cases (3.0%). Mean follow-up was 38 months (range 1-204 months), during which 23 vessels (17.3%) developed restenosis. Hostile-neck carotids (n=57) comprised 42.9% of all vessels treated and were responsible for 15 of 23 restenosis cases, resulting in a significantly higher restenosis rate than that of primary atherosclerotic lesions (26.3% vs 10.5%, p=0.017). By univariate analysis, the presence of calcified plaque was significantly associated with the incidence of in-stent restenosis (p=0.02).

CONCLUSIONS

Restenosis rates after carotid angioplasty and stenting are low. Patients with a history of ipsilateral neck surgery or irradiation are at higher risk for substantial radiographic and symptomatic restenosis.

Intracranial Blood Flow Changes After Extracranial Carotid Artery Stenting

BACKGROUND:

Carotid artery stenting is an endovascular treatment option for patients with extracranial carotid stenosis. However, intracranial blood flow changes following stenting have not been established.

OBJECTIVE:

To determine the effects of stenting on intracranial blood flow.

METHODS:

Records of patients who underwent stenting at our institution between 2004 and 2012 and had flow rates obtained pre- and poststenting by the use of quantitative magnetic resonance angiography were retrospectively reviewed. Percentage stenosis, stenosis length, and minimum vessel diameter were measured from cerebral angiography images.

RESULTS:

Eighteen patients were included. Mean age was 65 years with 67% presenting with symptomatic stenosis. Degree of stenosis ranged from 60% to 90%. Internal carotid artery (ICA) mean flow improved significantly poststenting from 174.9 ± 83.6 mL/min to 250.7 ± 91.2 mL/min (P = .011). Ipsilateral middle cerebral artery (MCA) flow, however, was not significantly altered poststenting (107.8 ± 41.6 mL/min vs 114.3 ± 36.3 mL/min; P = .28). Univariate analysis revealed that improved minimum vessel diameter after stenting, but not percentage stenosis (P = .18) or stenosis length (P = .45), is significantly associated with increased ICA flow (P = .02). However, improved percentage stenosis, stenosis length, minimum vessel diameter, and ICA flow poststenting were not significantly associated with increased MCA flow (P = .64, .38, .13, .37, respectively).

CONCLUSION:

ICA flow was compromised at baseline, improving 43% on average poststenting. Increased minimum vessel diameter was the factor most significantly associated with increased flow. Conversely, MCA flow was not significantly compromised at baseline nor altered after stenting, suggesting compensatory intracranial collateral supply prestenting that redistributes following ICA revascularization.

[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.

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.

The role of carotid angioplasty and stenting in carotid revascularization

OBJECTIVES

The gold standard procedure for carotid revascularization has been carotid endarterectomy. Several randomized trials demonstrate that it is more efficacious than medical management in stroke prevention for both symptomatic and asymptomatic patients when performed with low surgical morbidity. However, many high-risk patients not included in these trials are now being referred for carotid revascularization. Endovascular treatment of carotid stenosis with angioplasty and stenting has become an established alternative to carotid endarterectomy (CEA) for these patients. We provide a review of the current role of carotid stent and angioplasty.

METHODS

We reviewed our procedural techniques for carotid artery stenting (CAS) with an emphasis on the need for medical therapy before and after the procedure to reduce thromboembolic complications. We also retrospectively analysed our clinical outcomes and incidence of restenosis after CAS.

RESULTS

We evaluated 139 of 252 patients treated over a 10-year period who had a minimum of 6-month clinical and imaging (ultrasound and/or angiography) follow-up (average f/u=60 months). Our rate of major stroke, MI or death was 3%, and rate of peri-operative TIAs was 2%. Morbidity related to femoral sheath placement has been 1.5%, with one 'cold foot' resolved with heparin and one retroperitoneal hematoma requiring transfusion. Recurrent stenosis after CAS occurred in 4% of patients, predominately following radiation treatment where it was 15%.

DISCUSSION

Although CEA is the gold standard procedure to prevent stroke from carotid stenosis, CAS has an expanding role for revascualrization, particularly in high-risk patients. Several randomized prospective trials are ongoing to better define the indications for CAS versus CEA.

Characteristics of duplex sonographic parameters over time after successful carotid artery stenting

OBJECTIVES

Carotid duplex sonography is the primary tool for surveillance after carotid artery stenting, but the course of sonographic velocities over time after successful stenting is unclear. The purpose of this study was to describe carotid duplex sonographic velocity parameters after successful carotid artery stenting and to determine the predictors of poststent sonographic velocities.

METHODS

We queried institutional carotid stent and noninvasive vascular laboratory databases for internal carotid artery stents placed between January 2004 and June 2007. We included patients with stenosis of 20% or less on completion angiograms who had carotid duplex sonography within 30 days before and 7 days after stenting. The prestent peak systolic velocity (PSV), end-diastolic velocity (EDV), internal-to-common carotid artery PSV ratio, contralateral internal carotid artery velocities, stent type, open- versus closed-cell stent design, and days of follow-up were tested as potential predictors of poststent velocities.

RESULTS

Eighty-two of 498 patients met inclusion criteria. The mean PSV and PSV ratio decreased from 423.6 cm/s and 7.1 before stenting to 98.5 cm/s and 1.3 after stenting (both P < .001). During a median follow-up of 370 days, poststent velocities remained stable. All poststent velocities (PSV, EDV, and PSV ratio) were dependent on prestent ipsilateral and contralateral velocities. The poststent EDV was dependent on the type of stent. The upper range for 0% to 20% stenosis in the stented internal carotid artery was a PSV of 141 cm/s, an EDV of 42 cm/s, and a PSV ratio of 2.1 or lower.

CONCLUSIONS

With a median follow-up of 1 year, the PSV and PSV ratio remained stable over time in successfully stented carotid arteries. Deviations in sonographic parameters after initial poststent carotid duplex sonography should prompt an investigation for possible in-stent restenosis.

Cilostazol suppression of arterial intimal hyperplasia is associated with decreased expression of sialyl Lewis X homing receptors on mononuclear cells and E-selectin in endothelial cells

BACKGROUND

An inflammatory reaction in vascular tissue is a potential factor linking restenosis after angioplasty. Although cilostazol, a selective phosphodiesterase type 3 inhibitor that is a unique antiplatelet drug and vasodilator, has been reported to be anti-inflammatory, its effect on the inflammatory action of mononuclear cells homing to endothelial cells is not clearly understood. In this study, whether cilostazol inhibits neointimal formation and improves inflammatory actions by inhibiting sialyl Lewis X (SLX) expression on mononuclear cells and E-selectin expression on endothelial cells was evaluated.

METHODS

The effect of cilostazol (1, 3, 10, 30 μM) on expression of E-selectin in human umbilical vein endothelial cells and SLX in rat mononuclear cells stimulated with lipopolysaccharide by immunofluorescence and real-time polymerase chain reaction (n = 3) was studied. Additionally, a double-balloon injury model was used on rat carotid arteries to evaluate vascular intimal hyperplasia. 0.1% cilostazol was administered 3 days before the first balloon injury, and the second balloon injury was performed 7 days after the first injury. Cilostazol administration was continued until rats were sacrificed 14 days after the second angioplasty. The expression of SLX on mononuclear cells and E-selectin on endothelial cells by immunofluorescence (n = 10) and real-time polymerase chain reaction (n = 5) were studied.

RESULTS

Cilostazol effectively inhibited the expression of SLX on mononuclear cells and E-selectin on endothelial cells. Cilostazol inhibited the migration of mononuclear cells in neointimal regions and neointimal hyperplasia after balloon injury. The numbers of macrophages and T-lymphocytes and the hyperplasia area in neointimal regions decreased from 71.06 ± 20.04, 1121 ± 244.4 cells per section, 206,400 ± 96,150 mm(2) to 29.65 ± 16.73, 374.2 ± 124.5 cells per section, and 101,900 ± 16,150 mm(2) due to the administration of cilostazol.

CONCLUSIONS

These results demonstrate that the protective effect of cilostazol against neointimal hyperplasia may be mediated by its anti-inflammatory actions of mononuclear cells homing to endothelial cells by decreasing SLX and E-selectin expression.

CLINICAL RELEVANCE

It is reported that cilostazol inhibits neointimal hyperplasia by decreasing the expression of some cell-adhesion molecules. We evaluated the effects of cilostazol for the expression of sialyl Lewis X (SLX) on mononuclear cells and E-selectin on endothelial cells, which interaction is the first step of inflammation action. Cilostazol was thought to show the anti-inflammatory actions by decreasing SLX and E-selectin expression in addition to decreasing the expression of some cell-adhesion molecules.

Carotid artery stenting for primary and secondary stroke prevention

BACKGROUND

Carotid artery disease is a major cause of the disability and mortality associated with strokes. Ischemic stroke remains the major cause of adult disability and third-leading cause of adult mortality, and carotid revascularization currently remains the principal surgical tool in the prophylaxis of this disease.

METHODS

The literature representing the current body of evidence for carotid revascularization and the authors' current practices in the management of this disease are summarized in this review.

RESULTS

We provide an evidence-based narration of the development and current status of carotid artery stenting (CAS) by reviewing 1) the evidence for carotid revascularization from early carotid endarterectomy (CEA) trials; 2) the randomized trials comparing CEA and CAS, with a special emphasis on the recently published results of the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST), which have been a "game-changer," tipping the balance towards accepting CAS as a safe, equally effective, and durable alternative to CEA for all patients requiring carotid revascularization; and 3) the technical advances in CAS after enrollment of patients in the CREST.

CONCLUSIONS

CAS and CEA are complementary procedures. Judicious selection of the procedure is made on a case-by-case basis.

Cerebral artery restenosis following transluminal balloon angioplasty for vasospasm after subarachnoid hemorrhage

Background:

Although percutaneous transluminal angioplasty (PTA) is a widely used less invasive method to treat coronary artery stenosis, 10% of treated patients experience restenosis. Restenosis also occurs in approximately 5% of patients subjected to carotid artery stenting. Animal and human data suggested that restenosis is a response to injury incurred during PTA. As PTA has come into wide use to manage symptomatic cerebral vasospasm after subarachnoid hemorrhage (SAH) we studied the incidence of restenosis after PTA for cerebral vasospasm.

Methods:

Our study population consisted of 32 patients who had undergone PTA. They were followed by cerebral or 3DCT angiography or MRA for 6 126 months post-PTA (mean 48.65 months) to diagnose restenosis of the cerebral artery. We compared the size of the cerebral artery on the PTA and the contralateral side.

Results:

All 32 patients underwent successful PTA of 38 vascular territories and all manifested angiographic improvement of vasospasm. None suffered restenosis during the follow up period.

Conclusion:

PTA resulted in a significant improvement in the vessel diameter in patients with vasospasm after SAH and they did not suffer restenosis in the course of prolonged follow-up.

Clinical Referral Patterns for Carotid Artery Stenting Versus Carotid Endarterectomy

Background—

Carotid artery stenting (CAS) and carotid endarterectomy (CEA) are alternative strategies for stroke prevention in patients with atherosclerotic carotid disease. Although randomized clinical trials are the gold standard for assessing the relative benefits of different treatments, observational research is necessary for determining “real-world” effectiveness. Current recommendations limit the application of CAS to high-risk patients, undermining the ability to “balance” the characteristics of patients treated with either approach. We compared the clinical profiles of patients referred for CAS versus CEA in a large national database.

Methods and Results—

Clinical characteristics of 12 701 patients referred for CAS or CEA in the National Cardiovascular Data Registry–Carotid Artery Revascularization and Endarterectomy were compared for 44 clinical and demographic variables. To investigate the comparability of CAS and CEA patients, we stratified the cohort into quintiles of the propensity score for referral for CAS. Among 8069 patients referred for CAS and 4632 referred for CEA, the CAS patients had significantly more comorbidities. Whereas the propensity model balanced most covariates, the pooled standardized differences (≥10%) suggested persistent imbalance for ischemic heart disease, recent myocardial infarction, and restenosis of prior CAS/CEA, all of which were more common in the CAS group. After stratification of propensity scores by quintile, CEA patients comprised only 14% of the upper 2 quintiles.

Conclusions—

Characteristics of patients referred for CAS differ markedly from those referred for CEA. Because of extreme clinical disparities between these patients, generalizable comparative effectiveness analyses of observational data will be difficult.

Carotid artery interventions for restenosis after prior stenting: is it different from interventions of de novo lesions? Results from the carotid artery stent (CAS)--registry of the Arbeitsgemeinschaft Leitende Kardiologische Krankenhausärzte (ALKK)

OBJECTIVE

To compare characteristics and outcome of patients with re-stenoses after prior carotid artery stenting (CAS) treated with repeat carotid interventions (Re-CI) with CAS for de novo lesions.

BACKGROUND

The treatment of re-stenosis is a major problem in vascular interventions. Patients with re-stenoses after prior CAS treated with Re-CI are not well defined.

METHODS

We analyzed data from the prospective ALKK CAS Registry.

RESULTS

Out of 3,817 CAS procedures 95 were intended in 93 patients (2.5%) for a restenosis after prior CAS and 3,722 CAS in 3,655 patients (97.5%) for a de novo stenosis. There was no difference in age (p = 0.302) or distribution of gender (p = 0.545) between the two groups. Patients treated for a restenosis after CAS were less likely to be treated for a symptomatic lesion (22.7 vs. 40.1%, p = 0.001). Coronary heart disease (p = 0.017), peripheral arterial disease (p < 0.001) as well as diabetes mellitus (p = 0.004) were more prevalent in the restenosis group. Lesions were less complicated in restenosis patients, with less ulcers (7.4 vs. 19.9%, p = 0.003) and less severe calcifications (7.4 vs. 23.6%, p < 0.001). The intended interventions were more often not performed in the Re-CI group (9.5 vs. 3.3%; p = 0.001). In-hospital, the stroke or death rate was 0% in the Re-CI group as compared to 3.1% in the de novo group (p = 0.115).

CONCLUSIONS

Patients treated with Re-CI for repeat stenoses after prior CAS represent 2.5% of current CAS patients. Although representing a subgroup with more concomitant diseases, Re-CI seems to be associated with lower event rates as compared to CAS for de novo lesions.

Cutting balloon angioplasty in percutaneous carotid interventions

PURPOSE

To report a prospective feasibility study of cutting balloon angioplasty (CBA) applied in the predilation phase of carotid artery stenting (CAS) in highly calcified lesions.

METHODS

From January 2003 to February 2007, 178 consecutive patients (109 men; mean age 73.1+/-7.3 years) with highly calcified carotid lesions underwent CAS with CBA applied as a pre-specified strategy in the predilation phase of the procedure. All steps in the procedure were performed under cerebral filter protection. The cutting balloon ranged in diameter from 3 to 4 mm and was inflated at nominal pressures in the target lesion. Pre-CBA dilation with a low-profile coronary balloon was performed only when the cutting balloon was not able to cross the lesion. Selection of the filters and stents was at the operator's discretion. Primary endpoints were the all stroke and death rates at 30 days and 6 months. Secondary endpoints included cutting balloon success (positioning and full balloon inflation), CAS technical success (residual angiographic stenosis <30%), CAS procedural success (technical success and no complications), and in-hospital major complications.

RESULTS

Cutting balloon success was achieved in all 178 patients. In 32 (18.0%), pre-CBA dilation was necessary due to inability to cross the lesion with the cutting balloon initially. CAS technical success was achieved in all patients. One (0.6%) patient suffered transient neurological intolerance due to flow cessation from massive debris in the distal filter; this event was completely resolved after the filter was removed (CAS procedural success 99.4%). One patient suffered a major stroke at day 15 (0.6% 30-day all stroke and death rate). At the 6-month follow-up, 174 (97.7%) patients were evaluated; 1 patient died from myocardial infarction at day 35, and 2 patients died from non-neurological or cardiac causes at days 103 and 158. The cumulative all stroke and death rate was 2.2%.

CONCLUSION

These data suggest that CBA performed during the predilation phase of CAS in highly calcified lesion is a safe and useful method to prepare this lesion subset for stenting.

Duplex scan surveillance after carotid angioplasty and stenting: A rational definition of stent stenosis

OBJECTIVE

A duplex ultrasound (DUS) surveillance algorithm used after carotid endarterectomy (CEA) was applied to patients after carotid stenting and angioplasty (CAS) to determine the incidence of high-grade stent stenosis, its relationship to clinical symptoms, and the outcome of reintervention.

METHODS

In 111 patients who underwent 114 CAS procedures for symptomatic (n = 62) or asymptomatic (n = 52) atherosclerotic or recurrent stenosis after CEA involving the internal carotid artery (ICA), DUS surveillance was performed <or=30 days and every 6 months thereafter. High-grade stenosis (peak systolic velocity [PSV] >300 cm/s, diastolic velocity >125 cm/s, internal carotid artery stent/proximal common carotid artery ratio >4) involving the stented arterial segment prompted diagnostic angiography and repair when >75% diameter-reduction stenosis was confirmed. Criteria for >50% CAS stenosis was a PSV >150 cm/s with a PSV stent ratio >2.

RESULTS

All 114 carotid stents were patent on initial DUS imaging, including 90 (79%) with PSV <150 cm/s (94 +/- 24 cm/s), 23 (20%) with PSV >150 cm/s (183 +/- 34 cm/s), and one with high-grade, residual stenosis (PSV = 355). During subsequent surveillance, 81 CAS sites (71%) exhibited no change in stenosis severity, nine sites demonstrated stenosis regression to <50% diameter reduction, and five sites developed velocity spectra of a high-grade stenosis. Angiography confirmed >75% diameter reduction in all six CASs with DUS-detected high-grade stenosis, all patients were asymptomatic, and treatment consisted of endovascular (n = 5) or surgical (n = 1) repair. During the mean 33-month follow-up period, three patients experienced ipsilateral, reversible neurologic events at 30, 45, and 120 days after CAS; none was associated with severe stent stenosis. No stent occlusions occurred, and no patient with >50% CAS stenosis on initial or subsequent testing developed a permanent ipsilateral permanent neurologic deficit or stroke-related death.

CONCLUSION

DUS surveillance after CAS identified a 5% procedural failure rate due to the development of high-grade in-stent stenosis. Both progression and regression of stent stenosis severity was observed on serial testing, but 70% of CAS sites demonstrated velocity spectra consistent with <50% diameter reduction. The surveillance algorithm used, including reintervention for asymptomatic high-grade CAS stenosis, was associated with stent patency and the absence of disabling stroke.

Thirty-day morbidity and mortality rates for carotid artery intervention by surgeons who perform both carotid endarterectomy and carotid artery angioplasty and stent placement

Object

There is no known standard 30-day morbidity and mortality rate for high-risk patients undergoing carotid artery (CA) angioplasty and stent (CAS) placement. The high-risk registries and the Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy, Carotid Revascularization using Endarterectomy or Stenting Systems, and European Long-term Carotid Artery Stenting trials report different rates of morbidity and mortality, and each high-risk cohort has a different risk profile. The applicability of carotid endarterectomy (CEA) results from North American Symptomatic Carotid Endarterectomy Trial/Asymptomatic Carotid Atherosclerosis Study (NASCET/ACAS) remains uncertain, as most clinical CAS placement series reported to date typically included patients who would not have qualified for those studies. At the University at Buffalo, the same neurosurgeons perform triage in patients with CA disease and perform both CEA and CAS insertion. The authors review morbidity and mortality rates in this practice model.

Methods

Diagnosis-related group codes were used to search the authors’ practice database for patients who had undergone a completed CA intervention solely for the indication of atherosclerotic disease. One hundred twenty patients (129 vessels) treated with CAS surgery and 95 patients (100 vessels) treated with CEA met these criteria. In the CAS placement group, 78% of the patients would not have met NASCET/ACAS inclusion criteria. Demographic and clinical data for both groups were recorded on a spreadsheet for analysis.

At 30 days, one patient in the CEA group and two in the CAS group had died. Stroke occurred in one patient in the CAS group and none in the CEA group. Myocardial infarction (MI) occurred in one patient who underwent CAS surgery compared with three undergoing CEA. Composite incidence of stroke/death/MI was 3.3% in the CAS group and 3.2% in the CEA group.

Conclusions

In a practice in which surgeons perform both CEA and CAS surgery, the event rates for the CAS surgery equivalent to NASCET and ACAS rates for CEA can be achieved, even in high-risk NASCET/ACAS-ineligible patients in 78% of the CAS cases.

Guidelines for Screening of Extracranial Carotid Artery Disease: A Statement for Healthcare Professionals from the Multidisciplinary Practice Guidelines Committee of the American Society of Neuroimaging; Cosponsored by the Society of Vascular and Interventional Neurology

The aim of this new statement is to provide comprehensive and timely evidence-based recommendations on the screening for asymptomatic carotid artery stenosis in the general population and selected subsets of patients. Recommendations are included for high-risk persons in the general population; patients undergoing open heart surgery including coronary artery bypass surgery; patients with peripheral vascular diseases, abdominal aortic aneurysms, and renal artery stenosis; patients after radiotherapy for head and neck malignancies; patients following carotid endarterectomy, or carotid artery stent placement; patients with retinal ischemic syndromes; patients with syncope, dizziness, vertigo or tinnitus; and patients with a family history of vascular diseases and hyperhomocysteinemia. The recommendations are based on prevalence of disease, anticipated benefit, and concurrent guidelines from other professional organizations in selected populations.

Predictors of carotid stent restenosis

OBJECTIVES

We sought to determine the predictors of restenosis after carotid artery stenting and report alternatives for its management.

BACKGROUND

Carotid artery stenting has been increasingly accepted as an alternative to carotid endarterectomy (CEA). Predictors of carotid stent restenosis have not been firmly established, and management of restenotic lesions can be challenging.

METHODS

A retrospective, single-center review was conducted of 399 carotid stent procedures in 363 patients over 9 years, with a mean follow-up of 24 months (range 6-99 months). Clinical variables included age, gender, symptoms, hypertension, diabetes, tobacco use, renal insufficiency, coronary artery disease, hyperlipidemia, peripheral vascular disease, history of CEA, and history of neck radiation (XRT). Angiographic variables included reference vessel diameter, lesion length, post-stenting residual stenosis, stent diameter, type of stent, and number of stents.

RESULTS

Overall, restenosis occurred in 15 patients (3.8%). However, the restenosis occurred in 7 of 35 (20%) patients who had previous XRT, 6 of 57 (10.5%) patients who had previous CEA, and 2 of 9 (22%) patients who previously had both CEA and XRT. The only analyzed variables that were significantly associated with an increased risk of restenosis were previous CEA (OR 4.28, P = 0.008) or XRT (OR 11.3, P <or=<or= 0.0001). Restenosis was most often asymptomatic and detected at routine ultrasound follow-up. Restenotic lesions were successfully treated in 11/11 cases with angioplasty (27%) or stenting (73%). Four patients that are asymptomatic are being monitored closely with ultrasound. No patients required surgical therapy for restenosis.

CONCLUSIONS

Restenosis after carotid stenting is uncommon; however, patients with previous CEA or XRT are at increased risk. Restenotic lesions may be safely treated with further percutaneous interventions.

Risk factors for restenosis after carotid artery angioplasty and stenting

OBJECTIVES

With carotid artery stenting (CAS) becoming an ever-increasing procedure, we sought to determine risk factors for in-stent restenosis after CAS.

METHODS

Consecutive patients undergoing CAS between January 2002 and October 2004 at a tertiary care hospital were retrospectively reviewed. Patient, filter, and stent selection were left to the discretion of the attending surgeon. High-risk patients were defined by significant comorbidities or a hostile neck (prior surgery or radiation, or both), and risk factor analysis was performed. In-stent restenosis was defined as >60%, and selective angiography was performed on patients with an in-stent restenosis >80% by duplex ultrasound imaging.

RESULTS

Reviewed were 101 patients (55 men, 46 women) who underwent 109 CAS procedures. Comorbidities were typical for patients with atherosclerosis. In addition, 38% (n = 41) of procedures were performed in patients who had prior neck surgery, of which 29% (n = 32) had previous ipsilateral carotid endarterectomy. Seventeen patients (16%) had a history of neck cancer, and all had prior neck radiation. Median follow-up was 5 months (range, 0 to 30 months). Neurologic complications included three transient ischemic attacks (2.8%) and one nondisabling stroke (0.9%). There were two myocardial infarctions (1.9%) and no periprocedural deaths (30 days), for a combined stroke, myocardial infarction, and death rate of 2.9%. Asymptomatic in-stent restenosis developed in 12 carotids (11%), five of which required endovascular intervention, with a mean of 6 months to restenosis. Univariate Cox proportional hazard regression models were used to determine risk factors for the development of restenosis. Prior stroke, transient ischemic attack, amaurosis fugax, and prior neck cancer were all significant risk factors. When these significant risk factors from univariate analysis were put into multivariate analysis, however, the only marginally significant risk factor was prior neck cancer (P = .06). Kaplan-Meier analysis revealed a cumulative freedom from in-stent restenosis at 24 months of 88% +/- 6% in patients without neck cancer compared with 27% +/- 17% (P = .02) in patients with neck cancer.

CONCLUSIONS

CAS has been shown to be safe and effective in high-risk patients, with minimal adverse events.

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.

Endovascular Treatment of In-Stent Restenosis After Carotid Artery Stenting: Immediate and Midterm Results

PURPOSE

To evaluate the immediate and midterm outcome and analyze the debris captured after repeat endovascular intervention for the treatment of in-stent restenosis after carotid artery stenting (CAS).

METHODS

Thirty-one consecutive patients (27 men; mean age 63.7+/-13.0 years, range 53- 81) underwent repeat endovascular intervention (balloon angioplasty and provisional stenting) for the treatment of 32 in-stent restenoses following CAS.

RESULTS

Procedural success was achieved in all patients. An additional stent was implanted in 10 (31%) cases. No procedural complication was observed. Filter analysis was performed in 17 (53%) procedures; on 12 (71%), macroscopically visible material was captured. The histomorphometric analysis performed on 6 (19%) filters showed fibrin nets entrapping erythrocytes, leucocytes, platelets, and in 2 cases, fibrous hypercellular tissue fragments. At 30 days and during follow-up (mean 17+/-5 months), no deaths, transient ischemic attacks, or strokes were observed. In 1 (3.1%) patient, asymptomatic recurrence of ISR was found on Doppler ultrasonography and successfully treated with balloon angioplasty.

CONCLUSION

Repeat endovascular intervention using balloon angioplasty with provisional stenting and routine cerebral protection appears to be a feasible, safe, and clinically effective strategy for the treatment of in-stent restenosis after CAS.

Management of in-sent restenosis after carotid artery stenting in high-risk patients

BACKGROUND

Carotid artery stenting (CAS) has emerged as an acceptable treatment alternative in patients with carotid bifurcation disease. Although early results of CAS have been promising, long-term clinical outcomes remain less certain. We report herein the frequency, management, and clinical outcome of in-stent restenosis (ISR) after CAS at a single academic institution.

METHODS

Clinical records of 208 CAS procedures in 188 patients with carotid stenosis of 80% or greater, including 48 (26.5%) asymptomatic patients, during a 42-month period were analyzed. Follow-up serial carotid duplex ultrasound scans were performed. Selective angiography and repeat intervention were performed when duplex ultrasound scans showed 80% or greater ISR. Treatment outcomes of ISR interventions were analyzed.

RESULTS

Over a median 17-month follow-up, 33 (15.9%) ISRs of 60% or greater were found, according to the Doppler criteria. Among them, seven patients (3.4%) with a mean age of 68 years (range, 65-87 years) developed high-grade ISR (> or =80%), and they all underwent further endovascular interventions. Six patients with high-grade ISR were asymptomatic, whereas one remaining patient presented with a transient ischemic attack. Five of seven ISRs occurred within 12 months of CAS, and two occurred at 18 months' follow-up. Treatment indications for initial CAS in these seven patients included recurrent stenosis after CEA (n = 4), radiation-induced stenosis (n = 1), and high-cardiac-risk criteria (n = 2). Treatment modalities for ISR included balloon angioplasty alone (n = 1), cutting balloon angioplasty alone (n = 4), cutting balloon angioplasty with stent placement (n = 1), and balloon angioplasty with stent placement (n = 1). Technical success was achieved in all patients, and no periprocedural complications occurred. Two patients with post-CEA restenosis developed restenosis after ISR interventions, both of whom were successfully treated with cutting balloon angioplasty at 6 and 8 months. The remaining five patients showed an absence of recurrent stenosis or symptoms during a mean follow-up of 12 months (range, 3-37 months). By using the Kaplan-Meier analysis, the freedom from 80% or greater ISR after CAS procedures at 12, 24, 36, and 42 months was 97%, 97%, 96%, and 94%, respectively.

CONCLUSIONS

Our study showed that ISR after CAS remains uncommon. Successful treatment of ISR can be achieved by endovascular interventions, which incurred no instance of periprocedural complications in our series. Patients who developed ISR after CEA were likely to develop restenosis after IRS intervention. Diligent ultrasound follow-up scans are important after CAS, particularly in patients with post-CEA restenosis.

Computed Tomography Angiography of Carotid Stent. Comparison of Various Self-expandable Stent in a Phantom Model

SUMMARY

We evaluated Computed Tomography Angiography (CTA) of four different self-expandable stents in phantom model. Three stents ware made of nitinol and one was made of cobaltbased alloy. Each stent placed in plastic injector, filled with diluted iodinated contrast material, and placed on a plastic case filled with saline. CTA was performed on a four-detector CT scanner (detector collimation, 0.5mm: helical pitch 3.5). Axial and longitudinal reconstructions of CT imaging were compared with the instent attenuation. Three nitinol stents showed few artifact, and cobalt-based alloy stent was appeared artificial narrowing. In conclusion, CTA is useful for follow-up examination after carotid artery stenting (CAS) as a less invasive evaluation method.

Toward clinical equipoise: the current case for carotid angioplasty and stent placement

Recent advances in carotid artery (CA) stent placement procedures have propelled this technology into the forefront of treatment options for both symptomatic and asymptomatic patients with CA stenosis. Until recently, endarterectomy was the only surgical option for patients with CA occlusive disease. For high-risk surgical candidates, periprocedural stroke rates remained unacceptable and were significantly higher than those associated with the natural history of the disease. Advances in stent technology and improvements in antiplatelet and antithrombotic regimens, in conjunction with distal protection devices, have significantly lowered the risk of periprocedural complications for high-risk surgical candidates requiring CA revascularization. In this paper the authors review data gleaned from the important recent CA stent trials and address questions concerning the safety, efficacy, and durability of stent-assisted angioplasty for extracranial CA occlusive disease. Additionally, they review the role of noninvasive imaging modalities for the diagnosis and surveillance of CA disease in these high-risk patients.