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

Utility of ultrasound in the perioperative phase of carotid endarterectomy and carotid artery stent implantation

BACKGROUND

This article reviews the latest research results of the use of ultrasound technology in the perioperative period of carotid endarterectomy and carotid stenting and discusses the role of ultrasound technology in accurately evaluating carotid stenosis and plaque stability, assisting in selecting the most suitable surgical method, and providing optimal perioperative imaging to guide carotid endarterectomy (CEA) and carotid artery stenting (CAS) to reduce the occurrence and progression of stroke.

METHODS

The research published in recent years on the application of ultrasound in the perioperative period of CEA and CAS was reviewed through the databases of CNKI, Pubmed, and Web of Science.

RESULTS

Ultrasound has high clinical value in preoperative screening for indications, assessing the degree of carotid artery stenosis and the nature of plaque; monitoring hemodynamic changes intraoperatively to prevent cerebral ischemia or overperfusion; and evaluating surgical outcomes postoperatively and in late follow-up review.

CONCLUSION

Ultrasound is currently widely used perioperatively in CEA and CAS and has even become the preferred choice of clinicians to evaluate the efficacy of surgery and follow-up. The presence of vulnerable plaque is an important risk factor for ischemic stroke. Contrast-enhanced ultrasound is an excellent tool to assess plaque stability. In most studies, ultrasound has been used only in a short follow-up period after CEA and CAS, and data from longer follow-ups are needed to provide more reliable evidence.

Outcomes following carotid revascularization in patients with prior ipsilateral carotid artery stenting in the Vascular Quality Initiative

OBJECTIVE

The outcomes of carotid revascularization in patients with prior carotid artery stenting (CAS) remain understudied. Prior research has not reported the outcomes after transcarotid artery revascularization (TCAR) in patients with previous CAS. In this study, we compared the peri-operative outcomes of TCAR, transfemoral CAS (tfCAS) and carotid endarterectomy (CEA) in patients with prior ipsilateral CAS using the Vascular Quality Iniatitive.

METHODS

Using Vascular Quality Initiative data from 2016 to 2023, we identified patients who underwent TCAR, tfCAS, or CEA after prior ipsilateral CAS. We included covariates such as age, race, sex, body mass index, comorbidities (hypertension, diabetes, prior coronary artery disease, prior coronary artery bypass grafting/percutaneous coronary intervention, congestive heart failure, renal dysfunction, smoking, chronic obstructive pulmonary disease, and anemia), symptom status, urgency, ipsilateral stenosis, and contralateral occlusion into a regression model to compute propensity scores for treatment assignment. We then used the propensity scores for inverse probability weighting and weighted logistic regression to compare in-hospital stroke, in-hospital death, stroke/death, postoperative myocardial infarction (MI), stroke/death/MI, 30-day mortality, and cranial nerve injury (CNI) after TCAR, tfCAS, and CEA. We also analyzed trends in the proportions of patients undergoing the three revascularization procedures over time using Cochrane-Armitage trend testing.

RESULTS

We identified 2137 patients undergoing revascularization after prior ipsilateral carotid stenting: 668 TCAR patients (31%), 1128 tfCAS patients (53%), and 341 CEA patients (16%). In asymptomatic patients, TCAR was associated with a lower yet not statistically significant in-hospital stroke/death than tfCAS (TCAR vs tfCAS: 0.7% vs 2.0%; adjusted odds ratio [aOR], 0.33; 95% confidence interval [CI], 0.11-1.05; P = .06), and similar odds of stroke/death with CEA (TCAR vs CEA: 0.7% vs 0.9%; aOR, 0.80; 95% CI, 0.16-3.98; P = .8). Compared with CEA, TCAR was associated with lower odds of postoperative MI (0.1% vs 14%; aOR, 0.02; 95% CI, 0.00-0.10; P < .001), stroke/death/MI (0.8% vs 15%; aOR, 0.05; 95% CI, 0.01-0.25; P < .001), and CNI (0.1% vs 3.8%; aOR, 0.04; 95% CI, 0.00-0.30; P = .002) in this patient population. In symptomatic patients, TCAR had an unacceptably elevated in-hospital stroke/death rate of 5.1%, with lower rates of CNI than CEA. We also found an increasing trend in the proportion of patients undergoing TCAR following prior ipsilateral carotid stenting (2016 to 2023: 14% to 41%), with a relative decrease in proportions of tfCAS (61% to 45%) and CEA (25% to 14%) (P < .001).

CONCLUSIONS

In asymptomatic patients with prior ipsilateral CAS, TCAR was associated with lower odds of in-hospital stroke/death compared with tfCAS, with comparable stroke/death but lower postoperative MI and CNI rates compared with CEA. In symptomatic patients, TCAR was associated with unacceptably higher in-hospital stroke/death rates. In line with the postprocedure outcomes, there has been a steady increase in the proportion of patients with prior ipsilateral stenting undergoing TCAR over time.

Treatment Results of Carotid Artery Stenting with an Open-Cell Stent: Analysis of 734 Consecutive Cases at a Single Center

OBJECTIVE

In carotid artery stenting (CAS) for internal carotid artery stenosis, the stent is often selected according to the plaque properties and arterial tortuosity. In our institute, an open-cell stent is used as the first-line stent regardless of the characteristics of the lesion. This study was performed to examine the outcome of CAS with an open-cell stent as the real-world results.

METHODS

In total, 811 CAS procedures using open-cell stents were performed for internal carotid artery stenosis from April 2002 to December 2019. Of these patients, we excluded those with hyperacute conditions for which CAS was performed within 3 days of onset, those in whom acute mechanical thrombectomy was performed simultaneously with CAS, and those with stenosis due to arterial dissection. Thus, 734 patients were retrospectively analyzed. Perioperative and long-term outcomes and risk factors for perioperative infarction were investigated.

RESULTS

The periprocedural stroke rate and mortality rate were 3.7% (27/734) and 0.4% (3/734), respectively. Low-echoic plaque was a significant risk factor for periprocedural stroke in both univariate (P < 0.03) and multivariate (odds ratio, 2.69; 95% confidence interval, 1.14-6.66; P = 0.02) analyses. Cerebral infarction and high grade restenosis were observed in 15 (2.0%) and 17 (2.3%) patients during a median 50-month follow-up.

CONCLUSIONS

CAS with open-cell stents showed good results in terms of both the postoperative stroke incidence and long-term severe restenosis rate. However, low-echoic plaque was a risk factor for perioperative stroke incidence, which should be considered when deciding on the indication for CAS with an open-cell stent.

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 carotid endarterectomy and repeated carotid angioplasty and stenting for in-stent restenosis (CERCAS trial): a randomised study

BACKGROUND AND AIM

In-stent restenosis (ISR) belongs to an infrequent but potentially serious complication after carotid angioplasty and stenting in patients with severe carotid stenosis. Some of these patients might be contraindicated to repeat percutaneous transluminal angioplasty with or without stenting (rePTA/S). The purpose of the study is to compare the safety and effectiveness of carotid endarterectomy with stent removal (CEASR) and rePTA/S in patients with carotid ISR.

METHODS

Consecutive patients with carotid ISR (≥80%) were randomly allocated to the CEASR or rePTA/S group. The incidence of restenosis after intervention, stroke, transient ischaemic attack myocardial infarction and death 30 days and 1 year after intervention and restenosis 1 year after intervention between patients in CEASR and rePTA/S groups were statistically evaluated.

RESULTS

A total of 31 patients were included in the study; 14 patients (9 males; mean age 66.3±6.6 years) were allocated to CEASR and 17 patients (10 males; mean age 68.8±5.6 years) to the rePTA/S group. The implanted stent in carotid restenosis was successfully removed in all patients in the CEASR group. No clinical vascular event was recorded periproceduraly, 30 days and 1 year after intervention in both groups. Only one patient in the CEASR group had asymptomatic occlusion of the intervened carotid artery within 30 days and one patient died in the rePTA/S group within 1 year after intervention. Restenosis after intervention was significantly greater in the rePTA/S group (mean 20.9%) than in the CEASR group (mean 0%, p=0.04), but all stenoses were <50%. Incidence of 1-year restenosis that was ≥70% did not differ between the rePTA/S and CEASR groups (4 vs 1 patient; p=0.233).

CONCLUSION

CEASR seems to be effective and save procedures for patients with carotid ISR and might be considered as a treatment option.

TRIAL REGISTRATION NUMBER

NCT05390983.

What Is the Role of Transcarotid Artery Revascularization?

Carotid endarterectomy (CEA) is the gold-standard method of carotid revascularization in symptomatic patients with ≥50% and in asymptomatic patients with ≥70% stenosis. Transfemoral carotid artery stenting (TFCAS) has been associated with higher perioperative stroke rates compared to CEA in several studies. On the other hand, transcarotid artery revascularization (TCAR) has outperformed TFCAS in patients who are considered high risk for surgery. There is increasing data that supports TCAR as a safe and efficient technique with outcomes similar to those of CEA, but additional level-one studies are necessary to evaluate the long-term outcomes of TCAR in high- and standard-risk patients.

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 In-Stent Stenosis: Cutting Balloon Angioplasty: 2-Dimensional Operative Video

In-stent stenosis has a reported prevalence of 14% to 19% at 1-yr follow-up after carotid stenting and is associated with an increased risk of acute ischemic stroke.1,2 Risk factors include female sex, diabetes, and dyslipidemia. Cutting balloon angioplasty is a safe and effective treatment modality for the treatment of carotid in-stent stenosis, and alternative treatment options include observation with medical management and placement of another stent.3,4  The authors present the case of a 61-yr-old man with carotid in-stent restenosis and progressive worsening on serial imaging with ultrasound. The patient had a history of carotid stenting for symptomatic stenosis 6 mo prior and was maintained on aspirin and clopidogrel. In light of the progressive worsening, the in-stent stenosis was confirmed on computed tomography (CT) angiogram. The options were discussed with the patient and he consented for treatment with cutting balloon angioplasty. Final angiogram showed improvement of the luminal diameter with a residual stenosis of 15%. The patient tolerated the procedure well and was discharged home on postoperative day 1. Follow-up ultrasound demonstrated moderate improvement in peak systolic velocities, and the plan is to continue observation with a clinical follow-up and repeat carotid Dopplers at 3 mo.

Estimated Glomerular Filtration Rate as a Predictor of Restenosis After Carotid Stenting Using First-Generation Stents

This study evaluated the impact of the baseline estimated glomerular filtration rate (eGFR) on clinical and angiographic outcomes and long-term in-stent restenosis (ISR) rates in patients undergoing elective carotid artery stenting (CAS) procedures. Consecutive patients who underwent CAS were retrospectively enrolled (n = 456). At the end of 3 years of follow-up, patients who had died or were lost follow-up were excluded from the study and a final analysis was performed using data from the remaining 405 patients. The study population (n = 405) was divided into 3 tertiles based on the tertile values of the eGFR level (T1, T2, and T3); then, clinical and procedural characteristics and 3-year ISR rates were compared between the groups. An ISR of 50% was detected in 49 (12%) surviving patients. The 3-year ISR was higher among patients with the lowest eGFR values (T1) by 3.7 times (95% CI: 2.01-11.38) than that among patients with the highest eGFR values (T3). These significant relationships persisted following adjustment for confounders. A lower baseline eGFR level was significantly associated with an increased ISR rate. Decreased renal function may be a predictor of ISR after CAS using first-generation stents.

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.

Outcome of endovascular recanalization for intracranial in-stent restenosis

BACKGROUND AND PURPOSE

In-stent restenosis (ISR) is one of the long-term adverse outcomes of endovascular angioplasty and stenting for symptomatic intracranial arterial stenosis. In this study, we try to evaluate the safety and efficacy of endovascular treatment for intracranial ISR.

METHODS

We retrospectively collected patients with intracranial ISR who underwent endovascular treatment from June 2012 to August 2019 at a high-volume stroke center. Successful recanalization was defined as ≤30% residual stenosis. Stroke, myocardial infarction, and death after stenting within 30 days were used to evaluate periprocedural safety. Recurrent stroke in the territory of the culprit vessel and re-ISR in patients with clinical and vascular imaging follow-up data were used to evaluate the long-term outcome.

RESULTS

32 patients (59.6±7.2 years old) with ISR were recruited, including 22 patients (68.8%) treated with balloon dilatation, 8 patients (25%) with stenting, and 2 patients (6.3%) with failed procedures. Successful recanalization was achieved in 71.9% (23/32) of patients. There was no stroke, myocardial infarction or death within 30 days after the procedure. Recurrent stroke was found in 10.7% (3/28) of the patients, and re-ISR was found in 42.1% (8/19) of the patients. The re-ISR rate was lower in patients with stenting than in those with balloon dilatation (0% vs 57.1%, p=0.090), and in patients with successful recanalization than in those with unsuccessful recanalization (33.3% vs 75.0%, p=0.352), but with no statistically significant difference.

CONCLUSIONS

The periprocedural safety of endovascular treatment for intracranial ISR may be acceptable, but the long-term rates of recurrent stroke and re-ISR remain at high levels.

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.

Management of De Novo Carotid Stenosis and Postintervention Restenosis-Carotid Endarterectomy Versus Carotid Artery Stenting-a Review of Literature

The current literature indicates carotid endarterectomy (CEA) as the preferred treatment for symptomatic, moderate to severe carotid artery stenosis. However, recommendations for the management of acute tandem stenosis and complete occlusion, as well as postintervention restenosis of the carotid artery, remain controversial. Here, we review the literature evaluating these conditions and provide suggestions for clinical decision-making. Acute tandem stenosis or occlusion of the common and internal carotid arteries may be treated with angioplasty alone, reserving carotid artery stenting (CAS) or CEA for severe and complex cases. Patients who underwent CEA and developed ipsilateral restenosis may be subjected to angioplasty followed by CAS, which carries a lower risk of cranial nerve injury and subsequent restenosis of the artery. For post-CAS restenosis, current evidence recommends angioplasty and CAS for the management of moderate stenosis and CEA for severe stenosis of the carotid artery. Given the lack of level 1 evidence for the management of these conditions, the abovementioned recommendations may assist clinical decision-making; however, each case and its unique risks and benefits need to be assessed individually. Future studies evaluating and defining the risks and benefits of specific treatment strategies, such as CEA and CAS, in patients with acute tandem stenosis, occlusion, and postintervention restenosis of the carotid artery need to be conducted.

Photodynamic therapy of balloon-injured rat carotid arteries using indocyanine green

Photodynamic therapy (PDT) has been used to inhibit intimal hyperplasia in injured arteries. Because of the limited tissue penetration of visible light, an endovascular light source with a guided wire is often required for effective treatment. Indocyanine green (ICG), a near-infrared (NIR) photosensitizer, has been used in PDT for cancers. An extracorporeal light source may be used for shallow tissue because of the better tissue penetration of NIR light. The aim of this study was to evaluate the effect of ICG-PDT using extracorporeal NIR light on the inhibition of intimal hyperplasia in balloon-injured carotid arteries. A balloon injury (BI) model was used to induce intimal hyperplasia of carotid artery. Sprague-Dawley rats were divided into control, BI, BI + 1 × PDT, and BI + 2 × PDT groups. The control group underwent a sham procedure. PDT was performed 7 days after BI. In the BI + 1 × PDT group, ICG was administered 1 h before light irradiation. External illumination with 780-nm light-emitting diode light at a fluence of 4 J/cm² was applied. For the BI + 2 × PDT group, PDT was performed again at day 7, following the first PDT. Hematoxylin and eosin (H & E) staining was performed to assess vessel morphology. Arterial wall thickness was significantly larger in the BI group compared with the control group. ICG-PDT significantly reduced arterial wall thickness compared with the BI group. Repeated PDT further decreased arterial wall thickness to the level of the control group. These findings indicate a promising approach for the treatment of restenosis of carotid arteries.

Carotid endarterectomy for treatment of carotid in-stent restenosis: long-term follow-up results and surgery experiences from one single centre

Objective

Few studies have reported the surgical treatment of carotid in-stent restenosis (ISR), more data and longer follow-up are needed. We describe the surgical treatment of ISR by standard carotid endarterectomy (CEA) with stent removal, including long-term follow-up in 10 patients from our centre.

Methods

Ten patients from our centre who underwent CEA with stent removal for ISR were retrospectively analysed, including nine symptomatic and one asymptomatic ISR of at least 70% with mean age 67.3, the median time between carotid artery stenting and CEA was 17 months (range, 2–54 months).

Results

Standard CEA with stent removal was performed in all 10 patients without much technical difficulty (9 male and 1 female, mean age 67.3). Two cases were performed in hybrid operation room. There were a total of three complications that happened in three patients (30%) respectively. An asymptomatic dissecting aneurysm was formed on the petrous internal carotid artery in one patient who was followed up without intervention. In the second case, dissection occurred in the arterial wall distal to the site of the stent after stent removal revealed by intraoperative angiography, and another stent was implanted. The patient sustained temporary hypoglossal nerve dysfunction postoperatively. The third patient suffered cerebral hyperperfusion with complete recovery when discharged. No neurological complications occurred in other seven patients. After follow-up of 25 months (range, 11–54 months), one patient died of rectal cancer without ischaemic attack and restenosis 4 years postoperation; in one patient occurred recurrent symptomatic restenosis (90%) 1 year later; all other patients remained asymptomatic and without recurrent restenosis (>50%) by follow-up carotid ultrasound or CT angiography.

Conclusion

It seems that CEA with stent removal is a reasonable choice, by experienced hand, for symptomatic ISR with higher but acceptable complications. The indication of stent removal for asymptomatic ISR needs further observation.

Modified drug-eluting balloon angioplasty to treat high-risk carotid in-stent restenosis

Carotid artery stenting is commonly used to treat carotid artery stenosis. However, carotid in-stent restenosis remains a challenging problem. Herein, we report a difficult case of recurrent severe carotid in-stent restenosis with total contralateral internal carotid artery occlusion treated with repeat drug-eluting balloon inflations. The outcome after one year of follow-up showed a good result.

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.

Multicenter Experience of Surgical Explantation of Carotid Stents for Recurrent Stenosis

OBJECTIVE

A significant cohort of patients who have undergone carotid artery stenting (CAS) will have in-stent restenosis (ISR). The optimal management of symptomatic or severe ISR remains poorly defined. The purpose of this study was to describe the indications, treatment, and mid- to long-term outcomes of patients undergoing CAS explantation for ISR.

METHODS

All patients undergoing internal carotid artery stent explantation with carotid artery reconstruction at Mayo Clinic Rochester, Dartmouth-Hitchcock Medical Center, and Beth-Israel Deaconess Medical Center from 2003 to 2013 were retrospectively reviewed. Isolated common carotid artery stents were excluded. Demographics, comorbidities, indications for explantation, operative details, and perioperative and postoperative outcomes were reviewed.

RESULTS

Over the study interval, a total of 971 patients underwent carotid stenting across the 3 centers. Of these, 8 patients ultimately underwent CAS explantation with carotid artery reconstruction. Mean age was 69 years and 5 patients were male. Index stent placement was for symptomatic stenosis in 4 patients, asymptomatic restenosis after endarterectomy in 2 patients, asymptomatic high lesion in 1 patient, and asymptomatic critical stenosis in 1 patient. Indications for explantation were symptomatic ISR in 4 patients and asymptomatic severe ISR in 4 patients. Method of repair was stent explantation and patch angioplasty in 5 and en bloc carotid resection with bypass in 3 patients. There were no perioperative neurologic events or cranial nerve injuries. At a mean follow-up of 38.7 months, there were 2 late disabling ipsilateral strokes (14.4 months and 19.1 months).

CONCLUSION

A significant cohort of patients who have undergone CAS will have ISR. Although excellent perioperative results after surgical explantation can be obtained, this patient subgroup remains at risk for late neurologic events. Appropriate patient selection and diligent long-term follow-up are mandated to obtain optimal outcomes.

Anatomical and Technical Factors Influence the Rate of In-Stent Restenosis following Carotid Artery Stenting for the Treatment of Post-Carotid Endarterectomy Stenosis

Background

Carotid artery stenting (CAS) has been advocated as an alternative to redo surgery for the treatment of post-carotid endarterectomy (CEA) stenosis. This study analyzed the efficacy of CAS for post-CEA restenosis, focusing on an analysis of technical and anatomical predictive factors for in-stent restenosis.

Methods

We performed a retrospective monocentric study. We included all patients who underwent CAS for post-CEA restenosis at our institution from July 1997 to November 2013. The primary endpoints were the technical success, the presence of in-stent restenosis >50% or occlusion, either symptomatic or asymptomatic, during the follow-up period, and risk factors for restenosis. The secondary endpoints were early and late morbidity and mortality (TIA, stroke, myocardial infarction, or death).

Results

A total of 153 CAS procedures were performed for post-CEA restenosis, primarily because of asymptomatic lesions (137/153). The technical success rate was 98%. The 30-day perioperative stroke and death rate was 2.6% (two TIAs and two minor strokes), and rates of 2.2% (3/137) and 6.2% (1/16) were recorded for asymptomatic and symptomatic patients, respectively. The average follow-up time was 36 months (range, 6–171 months). In-stent restenosis or occlusion was observed in 16 patients (10.6%). Symptomatic restenosis was observed in only one patient. We found that young age (P = 0.002), stenosis > 85% (P = 0.018), and a lack of stent coverage of the common carotid artery (P = 0.006) were independent predictors of in-stent restenosis.

Conclusion

We identified new risk factors for in-stent restenosis that were specific to this population, and we propose a technical approach that may reduce this risk.

Carotid Artery Stenting with Distal Protection Using the Carotid Wallstent and Filterwire Neuroprotection: Single-Center Experience of 380 Cases with Midterm Outcomes

Emerging data have supported the clinical efficacy of carotid artery stenting (CAS) in stroke prevention in high-risk surgical patients. This study was performed to evaluate the midterm clinical outcome of CAS using the Carotid Wallstent and FilterWire distal protection (both Boston Scientific, Natick, MA) at an academic institution. Risk factors for in-stent restenosis (ISR) were also analyzed. Clinical variables and treatment outcome of high-risk patients who underwent Carotid Wallstent placement with FilterWire EX/EZ neuroprotection were analyzed during a recent 54-month period. Three hundred eighty CAS procedures were performed in 354 patients. Technical success was achieved in 372 cases (98%), and symptomatic lesions existed in 85 (24%) patients. No patient experienced periprocedural mortality or neuroprotective device–related complication. The 30-day stroke and death rate was 2.7%, and the overall complication rate was 6.9%. The overall major or fatal stroke rates in symptomatic and asymptomatic patients were 4.6% and 1.3%, respectively (not significant). The overall stroke and death rates between the symptomatic and asymptomatic groups were 5.8% and 2.4%, respectively (not significant). The median follow-up period was 29 months (range 1–53 months). With Kaplan-Meier analysis, the rates of freedom from 60% or greater ISR after CAS procedures at 12, 24, 36, and 48 months were 97%, 94%, 92%, and 90%, respectively. The rates of freedom from all fatal and nonfatal strokes at 12, 24, 36, and 48 months were 97%, 91%, 89%, and 85%, respectively. Multivariable analysis of significant univariate predictors identified that postendarterectomy stenosis (odds ratio [OR] 3.98, p = .02) and multiple stent placement (OR 3.68, p = .03) were independent predictors of ISR. Our study yielded favorable short-term and midterm clinical results using Carotid Wallstent with FilterWire neuroprotection. Late follow-up results showed low rates of fatal and nonfatal stroke and favorable ISR rates compared with other carotid stent trials. Postendarterectomy and multiple stent placement were associated with subsequent ISR.

Outcomes of 1000 Carotid Wallstent Implantations

Purpose: To evaluate the outcomes of carotid artery stenting (CAS) with Wallstents in a single-center experience. Methods: From January 2003 to December 2013, 1000 carotid artery lesions were treated with Carotid Wallstents under cerebral protection in 877 patients (mean age 71.7±8 years; 621 men). Indications for treatment were de novo lesions (>70% asymptomatic and >60% symptomatic); stenoses following carotid endarterectomy, radiation, or neck surgery; contralateral laryngeal nerve palsy; and high surgical risk. All the patients underwent duplex ultrasound and clinical evaluation during follow-up; radiography was performed when fracture or stent migration was suggested by ultrasound. Results: Procedure success was achieved in 99.3% of patients. Major and minor 30-day adverse events occurred in 2.1% of patients, including stroke (1.8%: 1.3% minor, 0.5% major), myocardial infarction (0.1%), and death (0.2%). Plaque morphology, nature of stenosis, and symptomatic status were significantly associated with the risk of postoperative neurologic events. Restenosis occurred in 3.2% at a mean 45.5-month follow-up and was significantly associated with diabetes, smoking, symptomatic stenosis, de novo stenosis, and calcification (plaque III/IV). No fracture or migration was registered during follow-up. Conclusion: CAS is a valid method for treating carotid artery disease, with very low rates of major adverse events and neurologic complications. The Carotid Wallstent seems to have excellent results, even with complex plaque morphology, and a low incidence of restenosis at follow-up.

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.

Comparative Review of the Treatment Methodologies of Carotid Stenosis

The treatment of carotid stenosis entails three methodologies, namely, medical management, carotid angioplasty and stenting (CAS), as well as carotid endarterectomy (CEA). The North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trial (ECST) have shown that symptomatic carotid stenosis greater than 70% is best treated with CEA. In asymptomatic patients with carotid stenosis greater than 60%, CEA was more beneficial than treatment with aspirin alone according to the Asymptomatic Carotid Atherosclerosis (ACAS) and Asymptomatic Carotid Stenosis Trial (ACST) trials. When CAS is compared with CEA, the CREST resulted in similar rates of ipsilateral stroke and death rates regardless of symptoms. However, CAS not only increased adverse effects in women, it also amplified stroke rates and death in elderly patients compared with CEA. CAS can maximize its utility in treating focal restenosis after CEA and patients with overwhelming cardiac risk or prior neck irradiation. When performing CEA, using a patch was equated to a more durable result than primary closure, whereas eversion technique is a new methodology deserving a spotlight. Comparing the three major treatment strategies of carotid stenosis has intrinsic drawbacks, as most trials are outdated and they vary in their premises, definitions, and study designs. With the newly codified best medical management including antiplatelet therapies with aspirin and clopidogrel, statin, antihypertensive agents, strict diabetes control, smoking cessation, and life style change, the current trials may demonstrate that asymptomatic carotid stenosis is best treated with best medical therapy. The ongoing trials will illuminate and reshape the treatment paradigm for symptomatic and asymptomatic carotid stenosis.

Percutaneous Treatment of Recurrent In-Stent Restenosis of Carotid Artery Stenting: A Case Report and State-of-the-Art Review

Patient: Male, 76

Final Diagnosis: Carotid in-stent restenosis

Symptoms: None

Medication: —

Clinical Procedure: Carotid Doppler ultrasound • carotid percutaneous angioplasty

Specialty: Cardiology

Continuous daily use of cilostazol prevents in-stent restenosis following carotid artery stenting: serial angiographic investigation of 229 lesions

BACKGROUND

Several studies have reported that cilostazol (CLS) may reduce in-stent restenosis (ISR) after carotid artery stenting (CAS). However, it is not known for how long CLS must be continued to prevent ISR.

METHODS

We retrospectively reviewed a prospectively collected database of patients who underwent elective CAS and follow-up angiography at 3 months and 1 year after the procedure. ISR was defined as stenosis of 50% or greater on digital subtraction angiography. The cumulative incidence rates of angiographic ISR were compared between the three groups, divided according to duration of CLS use : (1) patients who were maintained on CLS for 12 months or more after CAS (12M CLS group, n=70), (2) patients who were treated with CLS for the first 3 months after CAS (3M CLS group, n=23), and (3) patients who did not receive CLS (no CLS group, n=136).

RESULTS

A total of 229 lesions in 199 patients were included in our analysis. During a median follow-up of 365 days, ISR was detected in 15 lesions. The cumulative ISR rates overall and in the 12M CLS, 3M CLS, and no CLS groups were 5.6%, 0%, 5.0%, and 8.4%, respectively, at 1 year, and the log rank test showed that there was a significant difference between the three groups (p<0.05). Cox regression analysis demonstrated that the 12M CLS group had a significantly lower risk of ISR than the 3M CLS group (adjusted relative risk (aRR) 3.06e-10, 95% CI 0 to 0.51, p<0.05) and the no CLS group (aRR 1.41e-10, 95% CI 0 to 0.15, p<0.001), whereas no difference was found between the 3M CLS group and the no CLS group.

CONCLUSIONS

An overall cumulative ISR rate of 5.6% was documented angiographically at 1 year after CAS. Continuous daily use of CLS (for at least 1 year) may have a beneficial effect on long term prevention of ISR.

Balloons in endovascular neurosurgery: history and current applications

The use of balloons in the field of neurosurgery is currently an essential part of our clinical practice. The field has evolved over the last 40 years since Serbinenko used balloons to test the feasibility of occluding cervical vessels for intracranial pathologies. Since that time, indications have expanded to include sacrificing cervical and intracranial vessels with detachable balloons, supporting the coil mass in wide-necked aneurysms (balloon remodeling technique), and performing intracranial and cervical angioplasty for atherosclerotic disease, as well as an adjunct to treat arteriovenous malformations. With the rapid expansion of endovascular technologies, it appears that the indications and uses for balloons will continue to expand. In this article, we review the history of balloons, the initial applications, the types of balloons available, and the current applications available for endovascular neurosurgeons.

Carotid artery stenting has increased risk of external carotid artery occlusion compared with carotid endarterectomy

OBJECTIVE

The external carotid artery (ECA) can be an important source of cerebral blood flow in cases of high-grade internal carotid artery stenosis or occlusion. However, the treatment of the ECA is fundamentally different between carotid endarterectomy (CEA) and carotid artery stenting (CAS). CEA is routinely associated with endarterectomy of the ECA, whereas CAS excludes the ECA from direct flow. We hypothesize that these differences make ECA occlusion more common after CAS. Further, the impact of CAS on blood flow into the ECA is interesting because the flow from the stent into the ECA is altered in a way that may promote local inflammation and may influence in-stent restenosis (ISR). Thus, our objective was to use our institutional database to identify whether CAS increased the rate of ECA occlusion and, if it did, whether ECA occlusion was associated with ISR.

METHODS

Patients undergoing CAS or CEA from February 2007 to February 2012 were identified from our institutional carotid therapy database. Preoperative and postoperative images of patients who followed up in our institution were included in the analysis of ECA occlusion and rates of ISR.

RESULTS

There were 210 (67%) CAS patients and 207 (60%) CEA patients included in this analysis. Despite CAS patients being younger (68 vs 70 years), having shorter follow-up (12.5 vs 56.2 months), and being more likely to take clopidogrel (97% vs 35%), they had an increased rate of ECA occlusion (3.8%) compared with CEA patients (0.4%). CAS patients who went on to ECA occlusion had an increased incidence of prior neck irradiation (50% vs 15%; P = .03), but we did not identify an association of ECA occlusion with ISR >50%.

CONCLUSIONS

Whereas prior publications have identified increased rates of external carotid stenosis, this is the first demonstration of increased ECA occlusion after CAS. However, ECA occlusion is uncommon (∼4%) and did not have an association with ISR >50%. Future work modeling ECA flow patterns before and after CAS will be used to further test this interaction.

Influence of the hostile neck on restenosis after carotid stenting

BACKGROUND

Carotid artery stenting (CAS) for carotid stenosis is favored over carotid endarterectomy (CEA) in patients with a hostile neck from prior CEA or cervical irradiation (XRT). However, the restenosis rate after CAS in patients with hostile necks is variable in the literature. The objective of this study was to quantify differences in the in-stent restenosis (ISR)/occlusion and reintervention rates after CAS in patients with and without a hostile neck. Here we hypothesize that patients with hostile necks have an increased ISR, and that this increase may add morbidity to these patients.

MATERIALS AND METHODS

All patients undergoing CAS from 2007 to 2013 for carotid artery stenosis with follow-up imaging at our institution were queried from our carotid database (n = 236). Patients with hostile necks, including both CAS after prior CEA (n = 65) and prior XRT (n = 37), were compared with patients who underwent CAS for other reasons including both anatomical (n = 46) and medical comorbidities (n = 88). The primary end points were ISR, repeat intervention, and stent occlusion. Secondary end points of the study were stroke/myocardial infarction (MI)/death at 30 days, perioperative cardiovascular accident, transient ischemic attack, MI, groin access complications, hyperperfusion syndrome, and periprocedural hypotension or bradycardia.

RESULTS

Despite the hostile neck cohort being younger and having lower incidence of chronic obstructive pulmonary disease, coronary artery disease, and renal insufficiency, they had a greater incidence of ISR (11% vs. 4%; P = .03) and required more reinterventions (8% vs. 2%; P = .04). Stent occlusion and periprocedural morbidity/mortality were not different between groups.

CONCLUSIONS

Patients with hostile necks have increased risk of restenosis and need for reinterventions after CAS compared with patients without a hostile neck. However, they do not appear to have higher rates of stent occlusion or per-procedural events.

State of the art in carotid artery stenting: trial data, technical aspects, and limitations

The volume of carotid artery stenting (CAS) safety and efficacy data has grown exponentially over the last decade. Recent comparative data with carotid endarterectomy, the utility of embolic protection devices, peri-procedural medications, basic technical aspects of CAS, developments in carotid stent design, potential complications of CAS, and complication risk factors are discussed in this review.

Carotid restenosis after endarterectomy and stenting: a critical issue?

BACKGROUND

Carotid artery stenting (CAS) is currently considered a valid alternative to carotid endarterectomy (CEA) for the prevention of stroke in high-risk patients. One of the most important issues for both of these techniques is carotid restenosis. The aim of our study was to evaluate the incidence of post-CEA and post-CAS restenosis in a large cohort of patients in a single high-volume center.

METHODS

Between December 2000 and December 2010, 2453 CEA and 2628 CAS procedures were performed in the Vascular and Endovascular Surgery Unit at our institution. The mean age of patients was 73.8 years (range 55‒89 years), 78% of whom were men. Indications for carotid revascularization were: presence of symptomatic carotid artery stenosis of >70%, or asymptomatic stenosis of at least 80%, especially in patients with vulnerable plaques.

RESULTS

Mild and long-term results after CEA and CAS were similar. The overall perioperative neurologic complication rate (minor and major stroke) was similar in the 2 groups. At 1-year follow-up the restenosis rate after CEA was 1.58%. In-stent restenosis after CAS occurred in 1.67% of the procedures. All but 3 arteries had been treated for postsurgical restenosis. All lesions were approached secondarily with endovascular procedures. Statistical analysis demonstrated that post-CEA restenosis was the most important predictive factor for the development of in-stent restenosis after CAS.

CONCLUSIONS

This review of our 10-year experience confirms that patients who develop restenosis after CEA are also prone to developing in-stent restenosis after CAS.

A case of in-stent neoatherosclerosis 10 years after carotid artery stent implantation: observation with optical coherence tomography and plaque histological findings

We report a patient's case of slow progressive in-stent restenosis 10 years after bare-metal stent implantation to his carotid artery. We treated the patient with an additional stent placement under a distal filter protection device. Optical coherence tomographic assessment and plaque histology during the carotid artery stenting (CAS) revealed atheromatous change at in-stent neointima, which contained lipid-rich plaque and calcification deposits. These findings suggest that in-stent neoatherosclerosis may play an important role in the pathogenesis of very late stent restenosis after CAS.

Analysis of restenosis after carotid artery stenting: preliminary results using computational fluid dynamics based on three-dimensional angiography

Currently carotid artery stenting (CAS) is a widely used technique for the treatment of carotid artery stenosis. However, some patients with restenosis following CAS have been reported, resulting in potential clinical problems. The purpose of this study was to investigate the hemodynamic changes before and after CAS to find the factors that may influence restenosis. Five patients (two with restenosis, three without restenosis) were included in this study. The geometry and rheological conditions of the carotid arteries were obtained from three-dimensional digital subtraction angiography and ultrasound measurements. Computational fluid dynamics (CFD) modelling was performed to calculate wall shear stress (WSS), wall shear stress gradient (WSSG) and internal carotid artery (ICA) flow ratio. In addition, morphologic analysis was carried out. CFD results indicated that the WSSG of the restenosis group was significantly larger than that of the no-restenosis group. In the restenosis group, the WSS distribution after CAS showed a significant variation at the ICA. The average ICA flow ratio of the restenosis group was 43.5%, while in the no-restenosis group it was 68.6%. Furthermore, there were similar significant differences between the two groups during morphology analysis. CFD technology is useful for physicians in estimating haemodynamic changes during ICA stenosis treatment. These parameters, including ICA flow ratio and WSS distribution, may help to predict carotid restenosis. In future, CFD combined with other medical techniques such as digital subtraction angiography, MRI and pathology technologies will be available for the clinical estimation of ICA restenosis.

Clinical impact and predictors of carotid artery in-stent restenosis

To assess the incidence and clinical significance as well as predictors of in-stent restenosis (ISR) after carotid artery stenting (CAS) diagnosed with serial duplex sonography investigations. We analyzed 215 CAS procedures that had clinical and serial carotid duplex ultrasound investigations. The incidence of in-stent restenosis (ISR) and periprocedural as well as long-term clinical complications were recorded. The influence of an ISR on clinical complication was analyzed using Kaplan-Meier curves and clinical risk factors for the development of an ISR with multivariate logistic regression. During a median follow-up time of 33.4 months (interquartile range 15.3-53.7) an ISR of ≥70% was detected in 12 (6.1%) of 215 arteries (mean age of 68.1 ± 9.8 years, 71.6% male). The combined stroke and death rate during long-term follow-up was significantly higher in the group with an ISR [odds ratio (OR): 3.59, 95% confidence interval (CI): 1.50-8.59, p = 0.004]. After applying multivariate logistic regression analysis contralateral carotid occlusion (OR 10.11, 95% CI 2.06-49.63, p = 0.004), carotid endarterectomy (CEA) restenosis (OR 8.87, 95% CI 1.68-46.84, p = 0.010) and postprocedural carotid duplex ultrasound with a PSV ≥120 cm/s (OR 6.33, 95% CI 1.27-31.44, p = 0.024) were independent predictors of ISR. ISR after CAS during long-term follow-up is associated with a higher proportion of clinical complications. A close follow-up is suggested especially in those patients with the aforementioned independent predictors of an ISR. Against the background of a lacking established treatment of ISR, these findings should be taken into account when offering CAS as a treatment alternative to CEA.

Article Commentary: Late Outcomes of Carotid Artery Stenting: A Critical Review

The role of carotid artery stenting (CAS) as an alternative to carotid endarterectomy for the treatment of extracranial carotid occlusive disease for stroke prevention continues to evolve. Although technical and device refinements aimed at making CAS safer continue to this day, safety as measured by 30-day and 1-year outcomes has been the primary recipient of regulatory and practice attention. Relatively less emphasis has been placed on the incidence of recurrent stenosis after CAS and the efficacy of CAS in late stroke prevention. Data on late outcomes of CAS, including factors of potential influence, have been emerging and are addressed in this review.