Systematic and Comprehensive Comparison of Incidence of Restenosis Between Carotid Endarterectomy and Carotid Artery Stenting in Patients with Atherosclerotic Carotid Stenosis

OBJECTIVE

The purpose of the present study was to conduct a meta-analysis to systematically compare the incidence rates of in-stent restenosis after carotid artery stenting (CAS) and restenosis after carotid endarterectomy (CEA) for patients with atherosclerotic carotid stenosis.

METHODS

We retrieved potential academic reports comparing restenosis between CEA and CAS from the MEDLINE, PubMed, and EMBASE databases and the Cochrane Library from the date of the first CEA (January 1951) to July 20, 2018. The references of the identified studies were carefully reviewed to ensure that all available reports were included in the present study.

RESULTS

Our meta-analysis included 27 studies (15 randomized controlled trials, 12 nonrandomized controlled trials) and 20,479 participants with atherosclerotic carotid stenosis. A statistically significant difference was found in the cumulative incidence of restenosis >70% between CEA and CAS (risk difference, -0.033, 95% confidence interval [CI] -0.054 to -0.013; P = 0.002). For the restenosis >70% outcomes, although CEA was relevant with a lower rate of restenosis than CAS within 6 months (odds ratio [OR], 0.495; 95% CI, 0.285-0.861; P = 0.013) and 1 year (OR, 0.626; 95% CI, 0.483-0.811; P < 0.001), no statistically significant differences were found at 1.5 years (P = 0.210), 2 years (P = 0.123), 4 years (P = 0.124), 5 years (P = 0.327), or 10 years (P = 0.839). For the restenosis >50% outcomes, a significant difference was found in the rate of restenosis between the CEA and CAS groups within 1 year (OR, 0.317; 95% CI, 0.228-0.441; P < 0.001) but not at 1.5 years (P = 0.301), 2 years (P = 0.686), or 5 years (P = 0.920). No nominally significant effects were demonstrated with respect to the cumulative incidence of occlusion (P = 0.195) or the cumulative incidence of restenosis for symptomatic patients (P = 0.170) between CEA and CAS.

CONCLUSIONS

Although CAS was preferred over CEA, regardless of restenosis >50% or >70% after revascularization within 1 year, no significant difference was observed with extension of the follow-up period to >1 year. CAS was not associated with a greater cumulative incidence of occlusion or the cumulative incidence of restenosis for symptomatic patients.

Platelet Aggregability as a Predictor of Restenosis Following Carotid Endarterectomy

BACKGROUND

Antiplatelet drugs are administered before and after carotid endarterectomies (CEAs), but their efficacy for preventing restenosis remains unclear. Hence, this study aimed to identify associations between postoperative restenosis and platelet aggregability in CEA patients.

METHODS

Thirty-six consecutive CEA patients treated at Tokyo Women's Medical University from May 2013 to March 2015 were included in this retrospective study. Restenosis was defined as a stenosis ratio greater than or equal to 50% per the European Carotid Surgery Trial criteria or peak systolic velocity of 150 cm/s on carotid ultrasound. Platelet aggregability was measured turbidimetrically using a light-transmission platelet aggregometer and analyzed in terms of aggregation profiles for 2 concentrations of collagen used to induce aggregation (.25 and 2.0 μg/mL). Patients were automatically divided into 9 classes (Class 1-9, from the lowest to the highest aggregability) using a software program according to area under their platelet aggregation curves. Each class was subdivided into 10 further gradations for a total of 90 possible scores (10-99) using a software program. Patients were divided into high- and low-platelet aggregability score groups (cut-off = 49).

RESULTS

Data were analyzed for 36 of the 99 patients. Restenosis was observed in 10 (28%) patients. Restenosis incidence was significantly higher in patients with high-platelet aggregability score than in those with low-platelet aggregability score (50.0% [7/14] versus 13.6% [3 of 22]: P = .0176, odds ratio = 6.34, 95% CI: 1.27-31.57).

CONCLUSIONS

Platelet aggregability is a useful metric for predicting and preventing restenosis after CEA. It has potential as an indicator for determining the optimal dose of antiplatelet drugs.

The Society for Vascular Surgery practice guidelines on follow-up after vascular surgery arterial procedures

Although follow-up after open surgical and endovascular procedures is generally regarded as an important part of the care provided by vascular surgeons, there are no detailed or comprehensive guidelines that specify the optimal approaches with regard to testing methods, indications for reintervention, and follow-up intervals. To provide guidance to the vascular surgeon, the Clinical Practice Council of the Society for Vascular Surgery appointed an expert panel and a methodologist to review the current clinical evidence and to develop recommendations for follow-up after vascular surgery procedures. For those procedures for which high-quality evidence was not available, recommendations were based on observational studies, committee consensus, and indirect evidence. Recognizing that there are numerous published reports on the role of duplex ultrasound for surveillance of infrainguinal vein bypass grafts, the Society commissioned a systematic review and meta-analysis on this topic. The panel classified the strength of each recommendation and the corresponding quality of evidence on the basis of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system: recommendations were graded either strong or weak, and the quality of evidence was graded high, moderate, or low. The resulting recommendations represent a wide variety of open surgical and endovascular procedures involving the extracranial carotid artery, thoracic and abdominal aorta, mesenteric and renal arteries, and lower extremity arterial revascularization. The panel also identified many areas in which there was a lack of high-quality evidence to support their recommendations. This suggests that there are opportunities for further clinical research on testing methods, threshold criteria, and the role of surveillance as well as on the modes of failure and indications for reintervention after vascular surgery procedures.

Restenosis and risk of stroke after stenting or endarterectomy for symptomatic carotid stenosis in the International Carotid Stenting Study (ICSS): secondary analysis of a randomised trial

BACKGROUND

The risk of stroke associated with carotid artery restenosis after stenting or endarterectomy is unclear. We aimed to compare the long-term risk of restenosis after these treatments and to investigate if restenosis causes stroke in a secondary analysis of the International Carotid Stenting Study (ICSS).

METHODS

ICSS is a parallel-group randomised trial at 50 tertiary care centres in Europe, Australia, New Zealand, and Canada. Patients aged 40 years or older with symptomatic carotid stenosis measuring 50% or more were randomly assigned either stenting or endarterectomy in a 1:1 ratio. Randomisation was computer-generated and done centrally, with allocation by telephone or fax, stratified by centre, and with minimisation for sex, age, side of stenosis, and occlusion of the contralateral carotid artery. Patients were followed up both clinically and with carotid duplex ultrasound at baseline, 30 days after treatment, 6 months after randomisation, then annually for up to 10 years. We included patients whose assigned treatment was completed and who had at least one ultrasound examination after treatment. Restenosis was defined as any narrowing of the treated artery measuring 50% or more (at least moderate) or 70% or more (severe), or occlusion of the artery. The degree of restenosis based on ultrasound velocities and clinical outcome events were adjudicated centrally; assessors were masked to treatment assignment. Restenosis was analysed using interval-censored models and its association with later ipsilateral stroke using Cox regression. This trial is registered with the ISRCTN registry, number ISRCTN25337470. This report presents a secondary analysis, and follow-up is complete.

FINDINGS

Between May, 2001, and October, 2008, 1713 patients were enrolled and randomly allocated treatment (855 were assigned stenting and 858 endarterectomy), of whom 1530 individuals were followed up with ultrasound (737 assigned stenting and 793 endarterectomy) for a median of 4·0 years (IQR 2·3-5·0). At least moderate restenosis (≥50%) occurred in 274 patients after stenting (cumulative 5-year risk 40·7%) and in 217 after endarterectomy (29·6%; unadjusted hazard ratio [HR] 1·43, 95% CI 1·21-1·72; p<0·0001). Patients with at least moderate restenosis (≥50%) had a higher risk of ipsilateral stroke than did individuals without restenosis in the overall patient population (HR 3·18, 95% CI 1·52-6·67; p=0·002) and in the endarterectomy group alone (5·75, 1·80-18·33; p=0·003), but no significant increase in stroke risk after restenosis was recorded in the stenting group (2·03, 0·77-5·37; p=0·154; p=0·10 for interaction with treatment). No difference was noted in the risk of severe restenosis (≥70%) or subsequent stroke between the two treatment groups.

INTERPRETATION

At least moderate (≥50%) restenosis occurred more frequently after stenting than after endarterectomy and increased the risk for ipsilateral stroke in the overall population. Whether the restenosis-mediated risk of stroke differs between stenting and endarterectomy requires further research.

FUNDING

Medical Research Council, the Stroke Association, Sanofi-Synthélabo, and the European Union.

Editor's Choice - Comparison of Early Outcomes and Restenosis Rate Between Carotid Endarterectomy and Carotid Artery Stenting Using Propensity Score Matching Analysis

OBJECTIVE/BACKGROUND

Despite randomised evidence, the debate continues about the preferred treatment strategy for carotid stenosis in routine clinical practice. The aim of this study was to compare early outcomes and restenosis rates after carotid endarterectomy (CEA) and carotid stenting (CAS) in unselected patients using propensity score matching (PSM).

METHODS

The 30 day incidence of major adverse clinical events (MACE; defined as stroke, transient ischaemic attack, myocardial infarction, or death) and procedure related complications, as well as restenosis rates during follow-up were compared between unselected patients undergoing CEA or CAS between January 2002 and December 2015 at a single institution. PSM was used to balance the following factors between the CEA and CAS cohorts: age, sex, hypertension, diabetes, dyslipidaemia, smoking, atrial fibrillation, previous percutaneous coronary intervention or coronary artery bypass grafting, valvular heart disease, contralateral carotid occlusion, degree of carotid stenosis, and symptomatic status. Statistical comparisons of outcomes were based on logistic regression analysis and log rank test.

RESULTS

Of 1184 patients (654 CEA and 530 CAS), 452 PSM pairs of CEA and CAS patients were created. The CAS group showed a relatively higher 30 day incidence of MACE (7.5% vs. 2.4%; odds ratio [OR] 3.261, 95% confidence interval [CI] 1.634-6.509; p = .001) but a lower incidence of procedure related complications (1.5% vs. 5.3%; OR 0.199, 95% CI 0.075-0.528; p = .001). During a mean follow-up of 49.1 months (range 1-180 months), restenosis rates were higher after CAS than after CEA (1.5% vs. 1.0% at 12 months and 5.4% vs. 1.2% at 24 months, respectively; p = .008).

CONCLUSION

This PSM based observation reconfirmed previous trial results in both asymptomatic and symptomatic patients with carotid artery stenosis in routine clinical practice: CEA showed lower 30 day MACE and mid-term restenosis rates than CAS.

Transcervical Carotid Artery Stenting Using a Prosthetic Arterial Conduit: Case Series of a Novel Surgical Technique

We present a series of 4 patients with carotid restenosis following carotid endarterectomy (CEA) who underwent transcervical carotid artery stenting (CAS) using a novel prosthetic conduit technique. The patients were high risk for repeat CEA (short and obese necks) and had contraindications to transfemoral CAS (bovine arch, prior dissection). CAS was thus performed via a transcervical approach with a polytetrafluoroethylene conduit anastomosed to the proximal common carotid artery. The addition of a conduit allowed stent placement via a secure, stable platform. All patients recovered from their procedure without incident and are free from restenosis at follow-up.

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 Surgery Following Previous Carotid Endarterectomy Is Safe and Effective

With the perceived high risk of repeat carotid surgery, carotid angioplasty and stenting have been advocated recently as the preferred treatment of recurrent carotid disease following carotid endarterectomy. An experience with the operative treatment of recurrent carotid disease to document the risks and benefits of this procedure is presented. A review of a prospectively acquired vascular registry over a 10-year period (Jan. 1990-Jan. 2000) was undertaken to identify patients undergoing repeat carotid surgery following previous carotid endarterectomy. All patients were treated with repeat carotid endarterectomy, carotid interposition graft, or subclavian-carotid bypass. The perioperative stroke and death rate, operative complications, life-table freedom from stroke, and rates of recurrent stenosis were documented. During the study period 56 patients underwent repeat carotid surgery, comprising 6% of all carotid operations during this period. The indication for operation was symptomatic disease recurrence in 41 cases (73%) and asymptomatic recurrent stenosis? 80% in 15 cases (27%). The average interval from the prior carotid endarterectomy to the repeat operation was 78 months (range 3 weeks-297 months). The operations performed included repeat carotid endarterectomy with patch angioplasty in 31 cases (55%), interposition grafts in 19 cases (34%), and subclavian-carotid bypass in 6 cases (11%). There were three perioperative strokes with one resulting in death for a perioperative stroke and death rate of 5.4%. One minor transient cranial nerve (CN IX) injury occurred. Mean follow-up was 29 months (range, 1-1 16 months). Life-table freedom from stroke was 95% at 1 year and 90% at 5 years. Recurrent stenosis (? 80%) developed in three patients (5.4%) during follow-up, including one internal carotid artery occlusion. Two patients (3.6%) underwent repeat surgery. Repeat surgery for recurrent cerebrovascular disease following carotid endarterectomy is safe and provides durable freedom from stroke. Most patients are candidates for repeat endarterectomy with patching, but interposition grafting is often required. These results strongly support the continued role of repeat carotid surgery in the treatment of recurrent carotid disease.

Reoperation for Recurrent Carotid Stenosis: A Ten-Year Experience

Owing to the supposed risks of reoperation, carotid stenting has been proposed as a treatment for carotid restenosis. The purpose of this study is to determine the safety and efficacy of carotid reoperation. From March 1988 to March 1997, 40 patients, 18 men and 22 women (mean age: 65 years) underwent a total of 43 redo carotid procedures by our group. Two patients had both sides repaired and one required a second reoperation. Symptomatic recurrent carotid stenosis (>70%) was the indication in 25 reoperations and asymptomatic high-grade stenosis (>80%) was the indication in 18. The initial operation in 35 reoperations was carotid endarterectomy (CEA) with primary closure and in eight it was CEA with a prosthetic patch. The interval to recurrence was less in the 24 reoperations in patients who had myointimal hyperplasia (21 months) compared with 17 reoperations in patients with recurrent atherosclerosis (90 months). The other two reoperations were for an intimal flap 2 months after the original CEA, and for operative dilation of fibromuscular dysplastic bands missed on magnetic resonance angiography (MRA), distal to the site of a previous CEA.

The technique of reoperation included redo CEA in two, CEA with vein patch in eight, CEA with prosthetic patch in 22, vein interposition graft in five, and prosthetic interposition graft in five. In addition, operative dilation with an arterial dilator was used in one reoperation.

No perioperative strokes or deaths occurred other than one patient who died from cardiac complications following combined CEA and coronary artery bypass grafting. Operative morbidity consisted of pneumonia in one patient, reversible cranial nerve injury in four, and hematoma requiring evacuation in two. During follow-up (mean: 34 months), carotid occlusion resulted in a mild stroke in one patient, there were 10 late deaths not related to carotid disease, one patient required a reoperation, and three patients were lost to follow-up.

The authors conclude that reoperation for recurrent carotid stenosis, using standard vascular techniques, is both safe and effective; it should continue to be the mainstay of treatment when intervention is required.

Restenosis After Carotid Endarterectomy: Insight Into Risk Factors and Modification of Postoperative Management

BACKGROUND

Restenosis after carotid endarterectomy (CEA) is a potential complication after surgery for carotid stenosis. Stroke after CEA is a debilitating complication secondary to restenosis, and modification of postoperative care may be necessary to decrease the incidence of postoperative stroke after CEA. We sought to identify the clinical and patient factors that are associated with this complication.

METHODS

A retrospective analysis of all neurosurgical patients who underwent CEA for symptomatic or asymptomatic carotid stenosis was performed. Factors were compared against the outcome variable in a univariate analysis. A multivariate logistic regression model was used to identify independent predictive variables. We used Kaplan-Meier analysis to compare the effect of the variables on long-term event-free survival.

RESULTS

A total of 273 CEA procedures and their outcomes were analyzed with a mean follow-up of 50.7 months. Twenty-one patients had restenosis (7.6%). Rates of restenosis and restenosis-free survival were analyzed with Kaplan-Meier curves (log-rank test). In the multivariate model, a family history of stroke was the only variable that was significantly associated with restenosis after CEA.

CONCLUSIONS

Our findings suggest that a family history of stroke is an important factor that predisposes patients to restenosis after CEA. Restenosis-free survival is influenced by the presence of hyperlipidemia, age, and family history of stroke. Closer surveillance with more frequent follow-up and multidisciplinary management may be beneficial in patients who have these risk factors to prevent restenosis and prolong restenosis-free survival.

The presence of variant genotype of the mannose-binding lectin gene (MBL2) is not associated with increased restenosis rate in carotid surgery

BACKGROUND

We investigated the role of mannose-binding lectin (MBL) variant genotypes in patients with significant carotid restenosis after carotid endarterectomy (CEA) and who underwent a revision CEA.

METHODS

This was a cross-sectional analysis of 97 patients enrolled between 2001 and 2013. Three groups were investigated: group A included patients with internal carotid artery restenosis, group B included patients without restenosis after CEA, and group C included patients with peripheral arterial disease but without any signs of a carotid stenosis. Venous blood samples were drawn for the genotyping for MBL2 by polymerase chain reaction and for the determination of the MBL serum concentration by enzyme-linked immunoabsorbent assay.

RESULTS

The serum concentration of MBL was higher in patients with the normal genotype than in those with the genotype variants of MBL (95% confidence interval, 272.8-1008.7 μg/L; P = .001). There was no statistically significant difference among groups A, B, or C with respect to the presence of a variant genotype. Similarly, there was no significant gender difference regarding the presence of a variant genotype (P = .325).

CONCLUSIONS

The presence of a variant genotype of the MBL2 gene (and the correspondingly lower serum concentration of this molecule) was not correlated with the development of carotid restenosis after CEA beyond a follow-up of 12 months.

Primary Stenting for Recurrent Stenosis Following Carotid Endarterectomy

Background:

Carotid angioplasty and stenting is an accepted alternative treatment for severe restenosis following carotid endarterectomy. Balloons may not be required to effectively treat these lesions, given their altered histopathology compared to primary atherosclerotic plaque and tendency to be less calcified. Primary stenting using self-expanding stents alone may, therefore, be a safe and effective treatment for restenosis post-carotid endarterectomy.

Methods:

We review our experience in the treatment of 12 patients with symptomatic severe restenosis following carotid endarterectomy with primary stent placement alone.

Results:

Self-expanding stent placement alone reduced the mean internal carotid artery stenosis from 85% to 29%. Average peak systolic velocity determined at the time of ultrasonography decreased from 480 cm/s at initial presentation to 154 cm/s post-stent deployment and further decreased to 104 cm/s at one year follow-up. The stented arteries remained widely patent with no evidence of restenosis. A single peri-procedural ipsilateral transient ischemic event occurred. There were no cerebral or cardiac ischemic events recorded at one year of follow-up.

Conclusions:

In this series, primary stent placement without use of angioplasty balloons was a safe and effective treatment for symptomatic restenosis following carotid endarterectomy.

Comparison of morphological and rheological conditions between conventional and eversion carotid endarterectomy using computational fluid dynamics – a pilot study

Purpose:

To compare postoperative morphological and rheological conditions after eversion carotid endarterectomy versus conventional carotid endarterectomy using computational fluid dynamics.

Basic methods:

Hemodynamic metrics (velocity, wall shear stress, time-averaged wall shear stress and temporal gradient wall shear stress) in the carotid arteries were simulated in one patient after conventional carotid endarterectomy and one patient after eversion carotid endarterectomy by computational fluid dynamics analysis based on patient specific data.

Principal findings:

Systolic peak of the eversion carotid endarterectomy model showed a gradually decreased pressure along the stream path, the conventional carotid endarterectomy model revealed high pressure (about 180 Pa) at the carotid bulb. Regions of low wall shear stress in the conventional carotid endarterectomy model were much larger than that in the eversion carotid endarterectomy model and with lower time-averaged wall shear stress values (conventional carotid endarterectomy: 0.03–5.46 Pa vs. eversion carotid endarterectomy: 0.12–5.22 Pa).

Conclusions:

Computational fluid dynamics after conventional carotid endarterectomy and eversion carotid endarterectomy disclosed differences in hemodynamic patterns. Larger studies are necessary to assess whether these differences are consistent and might explain different rates of restenosis in both techniques.

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.

Durability of eversion carotid endarterectomy

OBJECTIVE

Carotid endarterectomy (CEA) remains the gold standard for treating carotid disease in selected symptomatic and asymptomatic patients, though carotid angioplasty and stenting has emerged as a safe alternative. The aim of this study was to assess the durability of CEA in a large series of patients followed up according to a strict clinical and ultrasonographic protocol.

METHODS

Over a 23-year period (1990-2012) a total of 1773 patients (1251 men and 522 women) with a mean age of 75.2 years (range, 31 to 96 years) who underwent 2007 consecutive primary eversion CEAs performed by the same surgeon under general anesthesia with electroencephalographic monitoring and selective shunting were prospectively followed up with ultrasonography at 1, 6, and 12 months, then yearly. A long-term follow-up (median, 11.2 years; mean, 12.9 years) was obtained for 1680 patients (94.8%). End points were perioperative (30-day) stroke and death and late carotid restenosis/occlusion rates.

RESULTS

More than two in three of the lesions (1446 of 2007, 72.1%) were symptomatic at the time of surgery, with a 25% rate of preoperative stroke. Preoperative antiplatelet or anticoagulant therapy was used by 1675 patients (94.4%), whereas 918 (51.8%) were receiving statin treatment. Overall, there were eight (0.4%) perioperative strokes and no deaths. During the follow-up, there were nine (0.47%) asymptomatic late carotid restenoses (six moderate [50%-69%] and three severe [≥ 70%]) and one (0.05%) carotid occlusion. Nine patients (0.47%) had late ipsilateral strokes, none of them related to restenosis/occlusion. Overall, there were 159 late deaths (9.4%).

CONCLUSIONS

The results of this study show that eversion CEA can be performed in symptomatic and asymptomatic patients with an extremely low perioperative stroke/death risk and a negligible incidence of late restenosis/occlusion, thus assuring a persistently good protection against the risk of cerebral ischemia.

Non-invasive imaging of carotid arterial restenosis using 3T cardiovascular magnetic resonance

BACKGROUND

Restenosis of the carotid artery is common following carotid endarterectomy, but analysis of lesion composition has mostly been based on histological study of explanted restenotic lesions. This study investigated the ability of 3T cardiovascular magnetic resonance (CMR) to determine the components of recurrent carotid artery disease and examined whether these differed from primary atherosclerotic plaque.

METHODS

50 patients underwent 3T CMR of both carotid arteries using a standard multicontrast protocol: time-of-flight (TOF), T1-weighted (T1W), T2-weighted (T2W), and PD-weighted (PDW) Turbo-Spin-Echo (TSE) sequences. 25 patients had previously undergone carotid endarterectomy (mean time since surgery 1580 days, range 45-6560 days), and 25 with primary asymptomatic atherosclerotic plaques served as controls. Two experienced reviewers analysed the multicontrast CMR images according to the presence or absence of major plaque features and assigned an overall classification type.

RESULTS

In patients with recurrent carotid disease following endarterectomy, the mean degree of restenosis was 51% (range 30-90%). Three distinct types of restenosis were identified: 5 patients (20%) showed CMR characteristics of fibro-atheromatous tissue, 11 patients (44%) had plaque features consistent with possible myointimal (fibromuscular) hyperplasia, and 6 patients (24%) had recurrent plaque suggestive of further lipid accumulation. Three patients (12%) showed evidence of post-surgical dissection of the carotid intima. Compared to primary atherosclerotic plaques, restenotic plaques were more likely to contain fibro-atheromatous tissue (p = 0.05) and smooth muscle (p < 0.01), and less likely to contain lipid (p < 0.01). Composition did not differ significantly between patients with early and late restenosis.

CONCLUSIONS

As defined by CMR, restenotic lesions of the carotid artery fall into three distinct types and differ in composition from primary atherosclerotic plaques. If validated by subsequent histological studies, these findings could suggest a role for CMR in detecting high-risk (i.e. lipid-rich) restenotic lesions.

Restenosis after carotid artery stenting and endarterectomy: a secondary analysis of CREST, a randomised controlled trial

BACKGROUND

In the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST), the composite primary endpoint of stroke, myocardial infarction, or death during the periprocedural period or ipsilateral stroke thereafter did not differ between carotid artery stenting and carotid endarterectomy for symptomatic or asymptomatic carotid stenosis. A secondary aim of this randomised trial was to compare the composite endpoint of restenosis or occlusion.

METHODS

Patients with stenosis of the carotid artery who were asymptomatic or had had a transient ischaemic attack, amaurosis fugax, or a minor stroke were eligible for CREST and were enrolled at 117 clinical centres in the USA and Canada between Dec 21, 2000, and July 18, 2008. In this secondary analysis, the main endpoint was a composite of restenosis or occlusion at 2 years. Restenosis and occlusion were assessed by duplex ultrasonography at 1, 6, 12, 24, and 48 months and were defined as a reduction in diameter of the target artery of at least 70%, diagnosed by a peak systolic velocity of at least 3·0 m/s. Studies were done in CREST-certified laboratories and interpreted at the Ultrasound Core Laboratory (University of Washington). The frequency of restenosis was calculated by Kaplan-Meier survival estimates and was compared during a 2-year follow-up period. We used proportional hazards models to assess the association between baseline characteristics and risk of restenosis. Analyses were per protocol. CREST is registered with ClinicalTrials.gov, number NCT00004732.

FINDINGS

2191 patients received their assigned treatment within 30 days of randomisation and had eligible ultrasonography (1086 who had carotid artery stenting, 1105 who had carotid endarterectomy). In 2 years, 58 patients who underwent carotid artery stenting (Kaplan-Meier rate 6·0%) and 62 who had carotid endarterectomy (6·3%) had restenosis or occlusion (hazard ratio [HR] 0·90, 95% CI 0·63-1·29; p=0·58). Female sex (1·79, 1·25-2·56), diabetes (2·31, 1·61-3·31), and dyslipidaemia (2·07, 1·01-4·26) were independent predictors of restenosis or occlusion after the two procedures. Smoking predicted an increased rate of restenosis after carotid endarterectomy (2·26, 1·34-3·77) but not after carotid artery stenting (0·77, 0·41-1·42).

INTERPRETATION

Restenosis and occlusion were infrequent and rates were similar up to 2 years after carotid endarterectomy and carotid artery stenting. Subsets of patients could benefit from early and frequent monitoring after revascularisation.

FUNDING

National Institute of Neurological Disorders and Stroke and Abbott Vascular Solutions.

Multicentric retrospective study of endovascular treatment for restenosis after open carotid surgery

OBJECTIVES

To analyse perioperative and midterm outcomes of carotid artery stenting (CAS) for symptomatic >50% and asymptomatic >70% restenosis after open carotid surgery (OCS).

DESIGN

A multicentric retrospective study.

METHODS

Outcome measures 30-day death, neurologic and anatomic (thrombosis, restenosis) events. Univariant and multivariant logistic regression analyses were performed to identify predictive factors for neurologic and anatomic events.

RESULTS

A total of 249 patients with a mean age of 69 years (range, 45-88) were treated for asymptomatic (86%) or symptomatic (14%) restenosis. The 30-day combined operative mortality and stroke morbidity was 2.8% in asymptomatic patients and 2.9% in symptomatic patients. Events during follow-up (mean duration, 29 months) included stroke in four cases, TIA in two, stent thrombosis in four and restenosis in 21. Kaplan-Meier estimates of overall survival, neurologic-event-free survival, anatomic-event-free survival and reintervention-free survival were 95.4%, 94.7%, 96.7% and 99.5%, respectively, at 1 year and 80.3%, 93.8%, 85.1% and 96%, respectively, at 4 years. Multivariant analysis showed that statin use was correlated with a lower risk of anatomic events (odds ratio (OR) = 0.15 (95% confidence interval (CI) 0.03-0.68), p = 0.01) and that bypass was associated with a higher risk of anatomic events than endarterectomy (OR = 5.0 (95% CI 1.6-16.6), p = 0.009).

CONCLUSION

CAS is a feasible therapeutic alternative to OCS for carotid restenosis with acceptable risks in the perioperative period. Restenosis rate may be higher in patients treated after bypass.

Open surgery remains a valid option for the treatment of recurrent carotid stenosis

OBJECTIVE

The choice between open surgery (OS) and transluminal carotid angioplasty with stenting (CAS) for the treatment of primary carotid stenosis remains controversial. However, CAS is considered a valid option for selected cases, such as recurrent carotid stenosis (RCS). Tertiary RCS seems to be a concerning issue after CAS but few large reports focused on the durability of CAS and OS. We report our early and long-term results with OS for RCS.

METHODS

From 1989 to 2006, perioperative data regarding 4245 consecutive surgical carotid reconstructions was prospectively collected. Patients whose indication was RCS were subjected to further analysis. Indications for surgery were symptomatic RCS >50% or asymptomatic RCS >80%. Freedom from neurologic event was defined as the absence of any ipsilateral symptom at any time after the procedure. Kaplan-Meier analysis was used to estimate freedom from reintervention, freedom from restenosis >50% and occlusion, freedom from neurologic event and survival.

RESULTS

A total of 119 patients (2.8%) with RCS underwent OS. The average time from the primary OS was 59.4 +/- 54.5 months (range, 2-204). Forty-nine patients (41%) were symptomatic. In 103 patients (87%), the technique did not differ from a primary approach. Postoperative (<30 days) combined stroke and death rate was 3.3%. Cranial nerve injury occurred in 5 cases (4.2%). With a mean follow-up of 53 +/- 48 months (range, 1-204), 3 patients had an ipsilateral stroke (including one hemorrhagic stroke) and 7 were diagnosed with a tertiary RCS >50%. At 5 years, Kaplan-Meier estimates of freedom from reintervention, freedom from restenosis and occlusion, freedom from neurologic event, and survival were 99%, 91%, 89%, and 91%, respectively.

CONCLUSION

OS for RCS is not a high-risk procedure and provides excellent long-term results, with low rates of tertiary RCS and reinterventions. The comparison between OS and CAS in this indication suffers from the absence of standardized follow-up paradigms after primary OS and the lack of prospective randomized trial comparing the two techniques. Despite these limitations in the available data, we conclude that OS should remain the first line therapy when treatment of RCS is indicated.

The role of endothelial cells and their progenitors in intimal hyperplasia

Intimal hyperplasia leading to restenosis is the major process that limits the success of cardiovascular intervention. The emergence of vascular progenitor cells and, in particular, endothelial progenitor cells has led to great interest in their potential therapeutic value in preventing intimal hyperplasia. We review the mechanism of intimal hyperplasia and highlight the important attenuating role played by a functional endothelium. The role of endothelial progenitor cells in maintaining endothelial function is reviewed and we describe how reduced progenitor cell number and function and reduced endothelial function lead to an increased risk of intimal hyperplasia. We review other potential sources of endothelial cells, including monocytes, mesenchymal stem cells and tissue resident stem cells. Endothelial progenitor cells have been used in clinical trials to reduce the risk of restenosis with varied success. Progenitor cells have huge therapeutic potential to prevent intimal hyperplasia but a more detailed understanding of vascular progenitor cell biology is necessary before further clinical trials are commenced.

Long-term risk of carotid restenosis in patients randomly assigned to endovascular treatment or endarterectomy in the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS): long-term follow-up of a randomised trial

Background

In the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS), early recurrent carotid stenosis was more common in patients assigned to endovascular treatment than it was in patients assigned to endarterectomy (CEA), raising concerns about the long-term effectiveness of endovascular treatment. We aimed to investigate the long-term risks of restenosis in patients included in CAVATAS.

Methods

413 patients who were randomly assigned in CAVATAS and completed treatment for carotid stenosis (200 patients had endovascular treatment and 213 patients had endarterectomy) had prospective clinical follow-up at a median of 5 years and carotid duplex ultrasound at a median of 4 years. We investigated the cumulative long-term incidence of carotid restenosis after endovascular treatment and endarterectomy, the effect of the use of stents on restenosis after endovascular treatment, risk factors for the development of restenosis, and the effect of carotid restenosis on the risk of recurrent cerebrovascular events. Analysis was by intention to treat. This study is registered, number ISRCTN01425573.

Findings

Severe carotid restenosis (≥70%) or occlusion occurred significantly more often in patients in the endovascular arm than in patients in the endarterectomy arm (adjusted hazard ratio [HR] 3·17, 95% CI 1·89–5·32; p<0·0001). The estimated 5-year incidence of restenosis was 30·7% in the endovascular arm and 10·5% in the endarterectomy arm. Patients in the endovascular arm who were treated with a stent (n=50) had a significantly lower risk of developing restenosis of 70% or greater compared with those treated with balloon angioplasty alone (n=145; HR 0·43, 0·19–0·97; p=0·04). Current smoking or a history of smoking was a predictor of restenosis of 70% or more (2·32, 1·19–4·54; p=0·01) and the early finding of moderate stenosis (50–69%) up to 60 days after treatment was associated with the risk of progression to restenosis of 70% or more (3·76, 1·88–7·52; p=0·0002). The composite endpoint of ipsilateral non-perioperative stroke or transient ischaemic attack occurred more often in patients in whom restenosis of 70% or more was diagnosed in the first year after treatment compared with patients without restenosis of 70% or more (5-year incidence 23% vs 11%; HR 2·18, 1·04–4·54; p=0·04), but the increase in ipsilateral stroke alone was not significant (10% vs 5%; 1·67, 0·54–5·11).

Interpretation

Restenosis is about three times more common after endovascular treatment than after endarterectomy and is associated with recurrent ipsilateral cerebrovascular symptoms; however, the risk of recurrent ipsilateral stroke is low. Further data are required from on-going trials of stenting versus endarterectomy to ascertain whether long-term ultrasound follow-up is necessary after carotid revascularisation.

Funding

British Heart Foundation; UK National Health Service Management Executive; UK Stroke Association.

MMP and TIMP alterations in asymptomatic and symptomatic severe recurrent carotid artery stenosis

OBJECTIVES

This study aimed to determine whether the plasma levels of matrix metalloproteinases (MMPs)-2 and -9 and their specific inhibitors (tissue inhibitors of metalloproteinases (TIMPs-1 and -2)) were altered in patients with symptomatic and asymptomatic, severe, recurrent carotid artery stenosis.

PATIENTS

Fifty-two patients (out of a total of 621) who had undergone successful carotid artery endarterectomy (CEA) between 1999 and 2003 and developed recurrent carotid artery stenosis (>/=70%) were included in the study. Restenosis was symptomatic in 23 patients and asymptomatic in 29 patients.

METHODS

Recurrent carotid artery stenosis was classified based on presentation, and as early-intermediate (6 months to 3 years) or late (>3 years). A detailed clinical history was taken and two blood samples were drawn from each patient to determine plasma levels of MMPs and TIMPs along with other biological parameters. Recurrent stenosis was confirmed with computed tomographic angiography.

RESULTS

Patients with symptomatic restenosis had significantly (p<0.001) higher active MMP-2 and -9 plasma values and significantly (p<0.001) lower TIMP-1 and -2 plasma values when compared to patients with asymptomatic restenosis. Plasma concentrations of active MMPs were higher and TIMPs lower in patients affected with late recurrent stenosis as compared to early-intermediate restenosis (p<0.001). No differences were recorded in latent MMP plasma values. Multivariate analysis showed that active MMP-2 and -9 were independent predictors of late recurrent carotid artery stenosis (p<0.03 and p<0.001, respectively).

CONCLUSIONS

Higher plasma concentrations of active MMP-2 and -9 were associated with an increased risk of carotid restenosis with plaque recurrence.

Recurrent carotid stenosis after CEA and CAS: diagnosis and management

Carotid endarterectomy (CEA) is the preferred method for cerebral revascularization in patients with symptomatic and asymptomatic high-grade extracranial carotid artery stenosis. Carotid artery stenting (CAS) has recently emerged as a less invasive alternative to endarterectomy. Carotid stenting has been demonstrated to be technically feasible and safe in high-risk patients. It has been approved as an acceptable method for revascularization in circumstances where CEA yields suboptimal results. While the final role of CAS in carotid revascularization will be determined on the basis of ongoing randomized trials, it is clear that stenting will continue to be performed in subgroups of patients with carotid stenosis. Therefore, it is anticipated that there will be a corresponding increase in the number of in-stent restenosis cases. Considerable controversy exists regarding the clinical significance, natural history, threshold for management, and appropriate intervention of recurrent carotid stenosis after endarterectomy and after stenting. This review analyzes current information on this important clinical problem and presents evidence-based recommendations for the diagnosis and management of recurrent carotid stenosis.

Restenosis after carotid endarterectomy: incidence and endovascular management

SUMMARY

Surgical procedures designed to restore vascular patency for a recurrent stenosis following carotid endarterectomy (CEA) are burdened with technical difficulties as well as with the possibility of serious neurological complications. An endovascular approach employing transluminal percutaneous angioplasty and stenting (PTAS) is a promising solution to these problems. We aimed to evaluate the incidence of carotid artery restenosis following CEA, and to evaluate the safety and efficacy of treating post-CEA restenosis with an endovascular technique (PTAS). One hundred and two patients who underwent CEA for symptomatic and asymptomatic stenosis were included in the analysis. Clinical and sonographic follow-up examinations identified carotid artery restenosis in 16 patients, who fulfilled our criteria for endovascular treatment. Carotid PTAS was performed on symptomatic patients with a stenosis over 60% of the artery lumen (n=7) and in asymptomatic patients with a stenosis over 80% (n=9). The post-PTAS patients were evaluated by duplex sonography every three months over a 24 month follow-up period for evidence of restenosis. The cumulative incidence of post-CEA carotid restenosis qualifying for PTAS was 9.3% during an average 12-month follow-up interval. The average time from CEA to carotid PTAS was 11 months. All 16 endovascular procedures were technically successful. All of the carotid arteries were widely patent following PTAS. There were no immediate perioperative complications. One patient died two days after carotid PTAS from a cerebral hemorrhage. Thirteen of the 16 patients remained asymptomatic and had no sonographic evidence of significant restenosis during the 24- month post-PTAS follow-up period. One patient developed a symptomatic 80% restenosis proximal to the stent six months after carotid PTAS. Another patient developed an asymptomatic 60% restenosis proximal to the stent at 24 months. One patient was lost to follow-up. Following CEA, there is a significant risk of developing a symptomatic or high-grade carotid artery restenosis requiring correction. Endovascular treatment (PTAS) of a recurrent stenosis after CEA is a safe and effective alternative to repeat carotid surgery.

Hyperhomocysteinemia and recurrent carotid stenosis

BACKGROUND

Hyperhomocysteinemia has been identified as a potential risk for atherosclerotic disease in epidemiologic studies. This study investigates the impact of elevated serum homocysteine on restenosis after carotid endarterectomy (CEA).

METHODS

In a retrospective study, we compared fasting plasma homocysteine levels of 51 patients who developed restenosis during an eight year period after CEA with 45 patients who did not develop restenosis. Restenosis was defined as at least 50% stenosis and was assessed by applying a routine duplex scan follow up investigation. Patients with restenosis were divided into a group with early restenosis (between 3 and 18 months postoperative, a total of 39 patients) and late restenosis (19 and more months; a total of 12 patients).

RESULTS

The groups were controlled for age, sex, and risk factors such as diabetes, nicotine abuse, weight, hypertension, and hyperlipidemia. Patients with restenosis had a significant lower mean homocysteine level (9.11 micromol/L; range: 3.23 micromol/L to 26.49 micromol/L) compared to patients without restenosis (11.01 miccromol/L; range: 5.09 micromol/L to 23.29 micromol/L; p = 0.03). Mean homocysteine level in patients with early restenosis was 8.88 micromol/L (range: 3.23-26.49 micromol/L) and 9.86 micromol/L (range 4.44-19.06 micromol/L) in late restenosis (p = 0.50).

CONCLUSION

The finding suggests that high plasma homocysteine concentrations do not play a significant role in the development of restenosis following CEA.

Operative Intervention for Carotid Restenosis is Safe and Effective

Carotid stenting has been proposed as an alternative to reoperative carotid endarterectomy (rCEA) for recurrent carotid stenosis. The purpose of this study is to prove the safety, effectiveness and durability of reoperation in long term follow up of 18 years in a community hospital setting. From March 1988 to April 2005 80 patients, 46 men and 34 women (mean age: 64.1 years) underwent a total of 83 operations. Symptomatic recurrent stenosis (>70%) was the indication in 32, asymptomatic high-grade stenosis (>80%) in 49, intimal flap in one and fibromuscular dysplasia (F.M.D), in one. The initial operation was carotid endarterectomy with primary closure in 60 and prosthetic patch in 23. The mean recurrences were at 23.3 months in 33 with myointimal hyperplasia, 105.4 months in 29 with recurrent atherosclerosis, 61.4 months in 19 with both hyperplasia and atherosclerosis, 2 months in one with intimal flap and 8 months in one with F.M.D bands. Reoperation utilized primary closure (3), vein patch (14), prosthetic patch (55), Gore-Tex interposition grafts (7), vein interposition grafts (3) and intraoperative dilation (1). No perioperative strokes or deaths occurred. One patient died from cardiac complications following combined rCEA and coronary artery bypass grafting. Operative morbidity consisted of reversible nerve injury (5), irreversible recurrent laryngeal nerve injury (1) and hematoma requiring evacuation (3). During follow up (3-153 months; mean: 50.9) carotid occlusion resulted in mild ipsilateral stroke in one patient, and one non-hemispheric stroke. There were 26 late deaths due to all causes, one due to CVA. Eight patients required reoperation (mean 53.4 months). Seven of these were hypertensive. Kaplan-Meier analysis of long-term follow up shows relatively high stroke free rates; at 153 months (12.75 years) the hemispheric stroke free rate was 98.67% and the all-stroke free rate was 95.85%. The survival estimate following redo surgery was 69.97% at 5 years and 40.23% at 10 years. We found that individuals on statin therapy (p-value=0.0042), and those on combination of statin and aspirin (p-value=0.0320), had significantly increased interval between primary and secondary operation. Increased age was correlated to a decreased time to redo surgery (p-value=<0.0001). We conclude that reoperation for recurrent carotid stenosis using standard vascular techniques is safe, effective, durable and cost effective. It should continue to be the mainstay of treatment when secondary intervention is required. Statins have a salutary effect on durability of the procedure and should be used when indicated.

Comparison of in-hospital outcomes of patients with versus without previous carotid endarterectomy undergoing carotid stenting (from the German ALKK CAS Registry)

Repeat carotid endarterectomy (CEA) for recurrent stenosis remains a challenging treatment option associated with high morbidity and mortality. Carotid artery stenting (CAS) is an attractive alternative management option for these patients. However, data about the effectiveness and safety of CAS in a large number of unselected patients are less known. We evaluated 3,070 patients who underwent CAS enrolled in a German registry from 1996 to 2006 at 31 sites. We compared clinical and angiographic features and in-hospital outcomes of patients with and without previous CEA who underwent CAS. Of 3,070 patients in the registry, 223 (7.3%) underwent CAS for restenosis after previous CEA. Median age was similar in patients with and without previous CEA (70 years, interquartile range 64 to 76 vs 71 years, interquartile range 65 to 76). Ipsilateral neurologic symptoms occurred in approximately 1/2 the patients in both groups. Other co-morbid conditions and angiographic or procedural factors did not differ between the 2 groups. In-hospital events including death (0% vs 0.4%), ipsilateral major stroke (1.4% vs 1.5%), death or major ipsilateral stroke (1.4% vs 1.7%), ipsilateral transient ischemic attack (1.9% vs 2.8%), myocardial infarction (0.4% vs 0.1%), and reintervention (0.7% vs 0.4%) were all low and not significantly different between those with and without previous CEA (p >0.05 for all comparisons). In conclusion, our data for a large number of patients who underwent CAS in a recent contemporary community-based practice attests to the low risk of periprocedural events in patients with recurrent stenosis after previous CEA. This low risk along with the less invasive nature of the procedure should make CAS an attractive and perhaps preferred option for the treatment of these patients.

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.

Carotid angioplasty and stenting for postendarterectomy stenosis: Long-term follow-up

BACKGROUND

Carotid angioplasty and stenting (CAS) for recurrent stenosis after carotid endarterectomy (CEA) has been proposed as an alternative to redo CEA. Although early results are encouraging, the extended durability remains unknown. We present the long-term surveillance results of CAS for post-CEA restenosis.

METHODS

Between 1998 and 2004, 57 CAS procedures were performed in 55 patients (36 men) with a mean age of 70 years. The mean interval between CEA and CAS was 83 months (range, 6 to 245). Nine patients (16%) were symptomatic.

RESULTS

CAS was performed successfully in all patients. No deaths or strokes occurred. A periprocedural transient ischemic attack (TIA) occurred in two patients. During a mean follow-up of 36 months (range, 12 to 72 months), two patients exhibited ipsilateral cerebral symptoms (1 TIA, 1 minor stroke). In 11 patients (19%), in-stent restenosis (> or =50%) was detected post-CAS at month 3 (n = 3), 12 (n = 3), 24 (n = 2), 36 (n = 1), 48 (n = 1), and 60 (n = 1). The cumulative rates of in-stent restenosis-free survival at 1, 2, 3, and 4 years were 93%, 85%, 82%, and 76%, respectively. Redo procedures were performed in six patients, three each received repeat angioplasty and repeat CEA with stent removal. The cumulative rates of freedom from reintervention at 1, 2, 3, and 4 years were 96%, 94%, 90%, and 84%, respectively.

CONCLUSION

Carotid angioplasty and stenting for recurrent stenosis after CEA can be performed with a low incidence of periprocedural complications with durable protection from stroke. The rate of in-stent recurrent stenosis is high, however, and does not only occur early after CAS but is an ongoing process.

Restenosis after carotid endarterectomy

Multiple randomised trials over the last decade for both symptomatic and asymptomatic carotid stenosis have proven the efficacy of carotid endarterectomy (CE) in reducing the risk of stroke. The long-term patency of the carotid artery after CE is an important factor in the success of the operation. The incidence of recurrent carotid stenosis (excluding residual lesions) ranges from 1 to 37% with only 0-8% of patients having restenosis-related symptoms (1). Generally, recurrent carotid stenosis is attributed to myointimal hyperplasia during the early postoperative period (within 3 years) or recurrent atherosclerosis thereafter. The management of recurrent carotid stenosis after CE remains a dilemma. It is generally accepted that operation for significant recurrent carotid stenosis is indicated for symptomatic patients, and several authors also recommend CE for >80% asymptomatic recurrent stenosis. Treatment of recurrent carotid stenosis involves repeat endarterectomy with patch angioplasty, although more recently endovascular techniques have been used.

Initial experience with eversion carotid endarterectomy: Absence of a learning curve for the first 100 patients

OBJECTIVE

Eversion carotid endarterectomy (CEA) has been touted as superior to standard CEA with patch closure because of allegedly lower restenosis rates and greater technical ease of performance. The purpose of this study was to evaluate the early experience of one vascular surgeon beginning to use this technique.

METHODS

This was a retrospective study in an academic vascular surgical practice. The first 100 patients undergoing CEA via the eversion technique were compared with 100 contemporaneous patients who had standard CEA with patch closure. Residual (first examination within 3 months) or recurrent postoperative duplex scan stenosis, perioperative neurologic deficit, and mortality were analyzed by cumulative sum failure and Kaplan-Meier life-table analysis.

RESULTS

Operative indications were not significantly different between eversion and standard CEA patients (63% vs 60% asymptomatic, 10% vs 7% stroke, 4% vs 5% amaurosis, and 23% vs 28% transient ischemia). Intraoperative shunting was more commonly used during eversion CEA (87% vs 59%; P < .01). Perioperative neurologic deficits included amaurosis (n = 1) after eversion CEA and transient cerebral ischemia (n = 1) and retinal infarction (n = 1) after standard CEA, with one cardiac death each. By 36 months, one other patient in each group had experienced a transient ischemic event, but there were no strokes. Four carotids occluded within 36 months of eversion CEA, compared with one occlusion after standard CEA (not significant). Patients undergoing eversion CEA showed no difference in critical (>80%) residual or recurrent stenosis rates. However, after eversion CEA, a greater degree of greater than 50% recurrent stenosis was observed at 36 months (38% vs 6%; P < .001) despite similar residual stenosis rates. Cumulative sum failure analysis showed no plateau among patients undergoing eversion CEA, thus indicating the absence of a learning curve, at least within the first 100 patients.

CONCLUSIONS

Despite enthusiasm by advocates for eversion CEA, the recurrent greater than 50% stenosis rate remained high for the first 100 patients who underwent this technique, with no evidence of a learning curve. This observation implies that vascular surgeons considering adoption of this technique should monitor their own early results carefully.

Determinants of carotid endarterectomy anatomic durability: Effects of serum lipids and lipid-lowering drugs

OBJECTIVES

Carotid endarterectomy (CEA) remains the gold standard for treatment of carotid stenosis. With inevitable comparisons of catheter-based therapy to all aspects of CEA, this study of a large contemporary series was undertaken to evaluate the determinants of anatomic durability of CEA.

METHODS

During the interval (1989 through 1999), 2,127 primary, isolated CEAs with selective patching (50.2%) were performed in 1,853 patients (61.8% male, 36.1% symptomatic). End points included patient longevity and perioperative morbidity as well as evidence of CEA anatomic durability as defined by duplex evaluation: CEA restenosis (moderate, >50%, or greater recurrent stenosis), which included CEA anatomic failure (severe, >70%, restenosis/carotid occlusion). The incidence of CEA recurrent stenosis was temporally assessed early (<2 years) and late (>2 years) after operation. Clinical and surgical variables potentially associated with the study endpoints were analyzed by univariate and multivariate methods.

RESULTS

The perioperative stroke and death rate was 1.4% and the 2-year and 10-year survival was 88.1% and 44.9%, respectively. Anatomic failure after CEA developed in 3.9% at 2 years and in 8.5% at 5 years; only 3.2% of CEA patients underwent reoperation during a mean follow-up of 73.4 months. Early (<2 years) analysis revealed 12.2% restenosis, whereas late (>2 years) results identified 9.8% progression of carotid stenosis and a 5.8% rate of anatomic failure. Multivariate analysis determined elevated creatinine (odds ratio [OR], 1.719, P < .001) and female gender (OR, 1.564; P < .02) correlated with early restenosis. Surgical patch closure and lipid-lowering drugs were protective for both early restenosis, with ORs of 0.543 (P < .0.001) and 0.601 (P < .007) and early anatomic failure ORs of 0.469 (P < .02) and 0.517 (P < .03), respectively. Although only elevated serum cholesterol (OR, 1.009; P < .03) correlated with late anatomic failure, only lipid-lowering drugs were protective for both late freedom from progression of disease (OR, 0.202; P < .0002) or late CEA anatomic failure (OR, 0.128; P < .0003).

CONCLUSIONS

The association of female gender and elevated cholesterol with recurrent carotid stenosis is confirmed, elevated creatinine is introduced as a risk factor, and surgical patch repair is protective for early CEA recurrent carotid stenosis. The unique findings of the significant, beneficial effects of lipid-lowering drugs on both early and late CEA anatomic durability and patient survival indicate that such therapy should be instituted in most patients after CEA.

Systematic Review of Early Recurrent Stenosis After Carotid Angioplasty and Stenting

BACKGROUND AND PURPOSE

Carotid angioplasty and stenting (CAS) has emerged as a potential alternative to endarterectomy (CEA) for the treatment of carotid artery disease. Aside from the periprocedural complication rates, the benefits of CAS will be affected by the incidence of recurrent carotid stenosis.

METHODS

We conducted a systematic analysis of all peer-reviewed studies reporting on the rate of restenosis (> or =50%) after CAS based on duplex ultrasound or angiography that were published between January 1990 and July 2004. We identified 34 studies that reported on a total of 4185 patients with a follow-up of 3814 arteries over a median of 13 months (range, 6 to 31 months). The ultrasound criteria and the lower thresholds for defining a recurrent stenosis were very heterogeneous.

RESULTS

The cumulative restenosis rates after 1 and 2 years were approximately 6% and 7.5% in those studies, which used a lower restenosis threshold > or =50% to 70% and approximately 4% in the first 2 years after CAS in those studies, which used a lower restenosis threshold >70% to 80%.

CONCLUSIONS

In reviewing the current literature, the early restenosis rates after CAS compare well with those reported for CEA. However, this analysis of the peer-reviewed literature also indicates that the early restenosis rates after CAS might be higher than previously suggested in observational surveys. Therefore, an active follow-up of all stented arteries seems to be warranted. Moreover, the bulk of endovascular data are derived from small studies with short follow-up periods so that the long-term durability of CAS still needs to be established in large trials. Ideally, these studies should use a clear and uniform definition of restenosis and identical follow-up schedules.

Frequency and management of recurrent stenosis after carotid artery stent implantation

Object. To determine the rate of hemodynamically significant recurrent carotid artery (CA) stenosis after stent-assisted angioplasty for CA occlusive disease, the authors analyzed Doppler ultrasonography data that had been prospectively collected between October 1998 and September 2002 for CA stent trials.

Methods. Patients included in the study participated in at least 6 months of follow-up review with serial Doppler studies or were found to have elevated in-stent velocities (> 300 cm/second) on postprocedure Doppler ultrasonograms. Hemodynamically significant (≥ 80%) recurrent stenosis was identified using the following Doppler criteria: peak in-stent systolic velocity at least 330 cm/second, peak in-stent diastolic velocity at least 130 cm/second, and peak internal carotid artery/common carotid artery velocity ratio at least 3.8. Follow-up studies were obtained at approximate fixed intervals of 1 day, 1 month, 6 months, and yearly. Angiography was performed in the event of recurrent symptoms, evidence of hemodynamically significant stenosis on Doppler ultrasonography, or both. Treatment was repeated because of symptoms, angiographic evidence of severe (≥ 80%) recurrent stenosis, or both of these.

Stents were implanted in 142 vessels in 138 patients (all but five patients were considered high-risk surgical candidates and 25 patients were lost to follow-up review). For the remaining 112 patients (117 vessels), the mean duration of Doppler ultrasonography follow up was 16.42 ± 10.58 months (range 4–54 months). Using one or more Doppler criteria, severe (≥ 80%) in-stent stenosis was detected in six patients (5%). Eight patients underwent repeated angiography. Six patients (three with symptoms) required repeated intervention (in four patients angioplasty alone; in one patient conventional angioplasty plus Cutting Balloon angioplasty; and in one patient stent-assisted angioplasty).

Conclusions. In a subset of primarily high-risk surgical candidates treated with stent-assisted angioplasty, the rates of hemodynamically significant restenosis were comparable to surgical restenosis rates cited in previously published works. Treatment for recurrent stenosis incurred no instance of periprocedure neurological morbidity.

Carotid artery stenting

Efficacy for carotid artery stenting (CAS) has not been confirmed by randomized clinical trial methodology in conventional risk patients. Although carotid endarterectomy (CEA) is considered the preferred method for carotid revascularization in the management of patients with symptomatic and asymptomatic extracranial carotid occlusive disease, comparisons between CAS and CEA are now underway. In North America, the CREST (Carotid Revascularization Endarterectomy versus Stent Trial) protocol is now completing its lead-in or credentialing phase as randomization of cases is initiated. In Europe, the CAVATAS (Carotid and Vertebral Artery Transluminal Angioplasty Study) and Stent Protected Angioplasty versus Carotid Endarterectomy trials are recruiting symptomatic patients for randomization between CEA and CAS. It is anticipated that these trials will publish definitive results within the next 1 to 3 years, and help guide the referral of patients for CAS and CEA in the future.

Durability of carotid endarterectomy for treatment of symptomatic and asymptomatic stenoses

PURPOSE

Although many studies have well established that carotid endarterectomy (CEA) is beneficial in selected patients with severe carotid disease, only a few large studies have focused on the durability of the surgical procedure. Carotid artery angioplasty and stenting (CAS) has recently been proposed as a potential alternative to CEA. We analyzed the incidence of late occlusion and recurrent stenosis after CEA.

METHODS

Over 13 years 1000 patients underwent 1150 CEA procedures to treat symptomatic and asymptomatic high-grade carotid stenosis. CEA procedures involving either traditional CEA with patching (n = 302) or eversion CEA (n = 848) were all performed by the same surgeon, with patients under deep general anesthesia and cerebral protection involving continuous electroencephalographic monitoring for selective shunting. All patients underwent postoperative duplex ultrasound scanning and clinical follow-up at 1, 6, and 12 months, and yearly thereafter. New neurologic events, late occlusions, and recurrent stenoses 50% or greater were recorded. Complete follow-up (mean, 6.2 years; range, 6-156 months) was obtained in 95% of patients (949 of 1000), for an overall average of 95% of procedures (1092 of 1150). Survival analysis was performed with the Kaplan-Meier life table method.

RESULTS

Perioperative (30-day) mortality rate was 0.3% (3 of 1000), and stroke rate was 0.9% (11 of 1150), with a combined mortality and stroke rate of 1.2%. The incidence of late occlusion and recurrent stenosis 70% or greater was 0.6% and 0.5%, respectively, with a combined occlusion and restenosis rate of 1.1%. Kaplan-Meier analysis showed that the rate of freedom from occlusion, restenosis 70% or greater, and combined occlusion and restenosis 70% or greater at 12 years was 99,4%, 99.5%, and 98.8%, respectively. Occlusion and restenosis developed asymptomatically.

CONCLUSIONS

CEA is a low-risk procedure for treating severe symptomatic and asymptomatic carotid disease, with excellent long-term durability. Proponents of CAS should bear this in mind before considering CAS as a routine alternative to CEA.

Chlamydia pneumoniae and atherosclerosis following carotid endarterectomy

BACKGROUND

Seroepidemiological studies have shown an association between raised antibody titres against Chlamydia pneumoniae, and carotid atherosclerosis or stroke. However, direct evidence for a causal link between arterial infection with C. pneumoniae and carotid disease remains weak. We hypothesized that long-term follow-up of patients with pathologically-proven arterial C. pneumoniae infection might provide further insight into the role of C. pneumoniae in carotid atherosclerosis.

METHODS

We followed a cohort of 70 carotid endarterectomy patients for ipsilateral restenosis, contralateral progression, and all-cause mortality (four year median follow-up period). All patients had presence or absence of C. pneumoniae in their carotid plaques documented by immunohistochemistry after endarterectomy. A survival function was generated and the log-rank test was used to assess the difference in survival between subjects with and without documented chlamydial infection in their plaque.

RESULTS

Baseline demographic and cardiovascular risk factors were similar between the two groups, and survival analysis demonstrated no difference (p>0.05) in all-cause mortality, or all-cause mortality combined with restenosis and progression.

CONCLUSIONS

Our data finds no causal role for C. pneumoniae in restenosis or progression of carotid disease or mortality in this patient population with advanced carotid atherosclerosis.

The effect of anticoagulation with subcutaneously delivered polyethylene glycol conjugated hirudin and recombinant tissue plasminogen activator on recurrent stenosis in the rabbit double-balloon injury model

Myointimal hyperplasia is the condition usually responsible for recurrent stenosis (restenosis) after endarterectomy, bypass grafting and angioplasty. Its cause is still not known. The present study examined whether inhibition of thrombin by tissue plasminogen activator (r-TPA) or polyethylene glycol recombinant hirudin (PEG-hirudin) could reduce restenosis in an animal model. Restenosis was induced in 20 cholesterol-fed rabbits. The right carotid artery underwent a double-balloon injury while left carotid artery acted as a control. Recombinant tissue plasminogen activator (1 mg kg(-1) s.c.) and PEG-hirudin (0.7 mg kg(-1) s.c.) were given subcutaneously with normal saline acting as a control. Blood levels of PEG-hirudin were measured by both ELISA and an Ecarin (activity) assay. Vessel dimensions were measured in histological sections, obtained from perfusion-fixed tissue, using computerised planimetry. The model reproduced many of the histological changes found in human restenosis, such as intramural thrombus, rupture of the elastic lamina, macrophage infiltration and smooth muscle migration. Reinjury caused an almost three-fold reduction in the area of the lumen (median 0.25 mm(2)) compared with uninjured vessels (median 0.72 mm(2)). The mean plasma levels of PEG-hirudin and r-tPA achieved were 291 ng/ml (S.E.M. 28 ng/ml) and 34 IU/ml (S.E.M. 12 IU/ml), respectively. PEG-hirudin significantly inhibited the effect of balloon injury on luminal area compared with saline-treated controls (0.21 versus 0.44 mm(2), respectively, P<0.05). Recombinant tPA also had a similar inhibitory affect, but this did not reach statistical significance (0.16 versus 0.44 mm(2), respectively, P>0.05). The magnitude of luminal narrowing was significantly reduced by subcutaneous injection of PEG-hirudin. Further studies are required to determine whether this effect can be enhanced by other antithrombins or improved methods of delivery.

Rationale and status of randomized controlled clinical trials in carotid artery stenting

Efficacy for carotid artery stenting (CAS) has not been confirmed by randomized clinical trial methodology. Although carotid endarterectomy (CEA) is considered the preferred method for carotid revascularization in the management of patients with asymptomatic and symptomatic extracranial carotid occlusive disease, comparisons between CAS and CEA are now underway. In North America, the CREST (Carotid Revascularization Endarterectomy versus Stent Trial) protocol is now completing credentialing cases as randomization of cases is initiated. In Europe, the CAVATAS (Carotid and Vertebral Artery Transluminal Angioplasty Study) and SPACE (Stent Protected Angioplasty versus Carotid Endarterectomy) trials are recruiting symptomatic patients for randomization between CEA and CAS. It is anticipated that these trials will publish definitive results within the next 1-3 years and help guide the referral of patients for CAS and CEA in the future.