Systematic Review of Early Recurrent Stenosis After Carotid Angioplasty and Stenting

Surveillance and risk factors for early restenosis following transcarotid artery revascularization

OBJECTIVE

Restenosis after transcarotid artery revascularization (TCAR) is a known complication. When identified in the early postoperative period, it may be related to technique. We evaluated our TCAR experience to identify potentially modifiable factors impacting restenosis.

METHODS

This is a single-institution, retrospective review of patients undergoing TCAR from November 2017 to July 2022. Restenosis was defined as >50% stenosis on duplex ultrasound (DUS) examination or computed tomographic angiography (CTA). Continuous variables were compared using Kruskal-Wallis's test. Categorical variables were compared using the Fisher's exact test.

RESULTS

Of 61 interventions, 11 (18%) developed restenosis within the median follow-up of 345 days (interquartile range, 103-623 days). Among these patients, 82% (9/11) had >50% stenosis, and 18% (2/11) had >80% stenosis. Both patients with high-grade restenosis were symptomatic and underwent revascularization. Diagnosis of post-TCAR restenosis was via DUS examination in 45% (5/11), CTA in 18% (2/11), or both CTA/DUS examination in 36% (4/11). Restenosis occurred within 1 month in 54% (6/11) and 6 months in 72% (8/11) of patients. However, three of the six patients with restenosis within 1 month had discordant findings on CTA vs DUS imaging. Patient comorbidities, degree of preoperative stenosis, medical management, balloon size, stent size, lesion characteristics, and predilatation angioplasty did not differ. Patients with restenosis were younger (P = .02), had prior ipsilateral endarterectomy (odds ratio [OR], 6.5; P = .02), had history of neck radiation (OR, 18.3; P = .01), and lower rate of postdilatation angioplasty (OR, 0.11; P = .04), without an increased risk of neurological events.

CONCLUSIONS

Although post-TCAR restenosis occurred in 18% of patients, only 3% of patients had critical restenosis and required reintervention. Patient factors associated with restenosis were younger age, prior endarterectomy, and history of neck radiation. Although early restenosis may be mitigated by improved technique, the only technical factor associated with restenosis was less use of postdilatation angioplasty. Balancing neurological risk, this factor may have increased application in appropriate patients. Diagnosis of restenosis was inconsistent between imaging modalities; current surveillance paradigms and diagnostic thresholds may warrant reconsideration.

Drug-Coated Balloon Angioplasty for Carotid Artery In-Stent Restenosis: Case Series

OBJECTIVES

Few case reports have demonstrated promising results of drug-coated balloons (DCBs) as an emerging management for carotid artery in-stent restenosis (CAISR). Herein, we report 6 cases of CAISR which were treated with a DCB with or without new stent deployment.

BACKGROUND

Carotid artery in-stent restenosis is a high-risk condition with an estimated incidence rate that varies widely from 6% to 40%. Several strategies are available now for the management of the CAISR including conventional balloon angioplasty, plaque modification balloon angioplasty, and new stent placement.

METHODS

A retrospective review of consecutive patients with a diagnosis of severe CAISR at Baylor Scott & White The Heart Hospital Plano from 2011 to 2021 was performed. This study was approved by the Baylor Scott & White Research Institute institutional review board.

RESULTS

Six patients underwent DCB angioplasty with or without stent placement under an embolic protection device. Resolution of CAISR was achieved in all cases with 0% to 10% residual stenosis in all cases. Following the procedure, 1 patient had a brief episode of syncope with balloon inflation with immediate recovery on deflation of the balloon. There were otherwise no significant neurological or cardiac events prior to discharge. All patients were asymptomatic at their follow-up visit with no neurological or cardiac events reported at 12, 24, and 36 months following the procedure.

CONCLUSION

While CAISR treatment remains a challenging condition, our study shows that the use of DCB with or without stent placement is a feasible and promising treatment option when compared with other conventional treatment options.

CLINICAL IMPACT

Carotid artery in-stent restenosis treatment remains a challenging condition. Our study shows that the use of drug coated balloon with or without stent placement is a feasible and promising treatment option when compared with current conventional treatment options.

Computational modeling of low-density lipoprotein accumulation at the carotid artery bifurcation after stenting

Restenosis typically occurs in regions of low and oscillating wall shear stress, which also favor the accumulation of atherogenic macromolecules such as low-density lipoprotein (LDL). This study aims to evaluate LDL transport and accumulation at the carotid artery bifurcation following carotid artery stenting (CAS) by means of computational simulation. The computational model consists of coupled blood flow and LDL transport, with the latter being modeled as a dilute substance dissolved in the blood and transported by the flow through a convection-diffusion transport equation. The endothelial layer was assumed to be permeable to LDL, and the hydraulic conductivity of LDL was shear-dependent. Anatomically realistic geometric models of the carotid bifurcation were built based on pre- and post-stent computed tomography (CT) scans. The influence of stent design was investigated by virtually deploying two different types of stents (open- and closed-cell stents) into the same carotid bifurcation model. Predicted LDL concentrations were compared between the post-stent carotid models and the relatively normal contralateral model reconstructed from patient-specific CT images. Our results show elevated LDL concentration in the distal section of the stent in all post-stent models, where LDL concentration is 20 times higher than that in the contralateral carotid. Compared with the open-cell stents, the closed-cell stents have larger areas exposed to high LDL concentration, suggesting an increased risk of stent restenosis. This computational approach is readily applicable to multiple patient studies and, once fully validated against follow-up data, it can help elucidate the role of stent strut design in the development of in-stent restenosis after CAS.

Safety Evaluation of Primary Carotid Stenting: Transcranial Doppler and MRI

BACKGROUND AND PURPOSE

Cerebral emboli are generated by every step of standard carotid angioplasty and stenting. Primary carotid stenting (PCS) is a technique in which the use of balloon angioplasty (BA) is minimized to decrease the embolic load. The primary aim of this study is to establish the number of emboli generated by each step of primary stenting and determine the relationship to new diffusion (DWI) lesions on subsequent magnetic resonance imaging (MRI).

METHODS

Eighty-five patients with severe, symptomatic carotid stenosis were prospectively recruited and underwent carotid stenting. Intraoperative transcranial Doppler was performed in 77 patients. The number and size of microemboli for each of seven procedural steps were recorded. Correlation was made with the number and location of new DWI lesions.

RESULTS

PCS was performed in 73 patients. BA was required in 12 patients. The mean number of microemboli was 114, and most microemboli were generated by stent deployment, followed by BA. Balloon techniques generated significantly more emboli than primary stenting (p = 0.017). There was a significant relationship between total microemboli and new DWI lesions (p = 0.009), and between new DWI lesions in multiple territories and the severity of pretreatment stenosis (p = 0.002).

CONCLUSIONS

During PCS, more emboli are generated by stent deployment than during any other stage of the procedure. When BA is necessary, more malignant emboli are generated but total emboli are unchanged and there is no difference in new diffusion lesions on MRI. PCS is safe and is not inferior to historical controls for the generation of new DWI lesions.

Carotid computed tomography angiography after cobalt-based alloy carotid artery stenting using ultra-high-resolution computed tomography with model-based iterative reconstruction

In conventional carotid computed tomographic angiography, the artifacts of the stent vary depending on the structure and characteristics of the alloy type. Cobalt-based alloy stents have been reported to exhibit high artifacts, and accurate evaluation of the internal lumen can be difficult. Recently, ultra-high-resolution computed tomography scanner systems have become available for clinical practice. The primary features of this computed tomography scanner are a 0.25-mm detector row width and a 1024 × 1024 matrix. We report a case-series of carotid artery stenting using a cobalt-based alloy stent scanned by an ultra-high-resolution computed tomography scanner system and model-based iterative reconstruction. We also report that the combination of the ultra-high-resolution computed tomography scanner system with model-based iterative reconstruction would be useful to evaluate vessel patency after placement of a cobalt-based alloy stent.

Cilostazol: a Review of Basic Mechanisms and Clinical Uses

Primarily used in the treatment of intermittent claudication, cilostazol is a 2-oxyquinolone derivative that works through the inhibition of phosphodiesterase III and related increases in cyclic adenosine monophosphate (cAMP) levels. However, cilostazol has been implicated in a number of other basic pathways including the inhibition of adenosine reuptake, the inhibition of multidrug resistance protein 4, among others. It has been observed to exhibit antiplatelet, antiproliferative, vasodilatory, and ischemic-reperfusion protective properties. As such, cilostazol has been investigated for clinical use in a variety of settings including intermittent claudication, as an adjunctive for reduction of restenosis after coronary and peripheral endovascular interventions, and in the prevention of secondary stroke, although its widespread implementation for indications other than intermittent claudication has been limited by relatively modest effect sizes and lack of studies in western populations. In this review, we highlight the pleiotropic effects of cilostazol and the evidence for its clinical use.

Hybrid Recanalization for the Treatment of Carotid/Vertebral In-stent Restenosis or Occlusion: Pilot Surgery Experiences From One Single Center

Background : The hybrid recanalization of internal carotid artery (ICA) and vertebral artery (VA) in-stent restenosis or occlusion using a combination of endarterectomy and endovascular intervention has achieved technical success. We present our surgical experiences to further evaluate the safety and efficacy of the hybrid technique for the treatment of in-stent restenosis and occlusion. Methods : A cohort of 12 refractory patients with in-stent restenosis or occlusion who underwent hybrid recanalization, a combination of endarterectomy and endovascular intervention, were retrospectively analyzed. Medical records, including presenting symptoms, comorbidities, contralateral ICA/VA findings, use of antiplatelet drugs, postoperative complications, and angiographic outcomes, were collected. Results : Among 415 consecutive patients with ICA, common carotid artery, and V1 segment lesions, 12 refractory patients (2.89%) with 13 cases were enrolled in our study (1 female and 11 male). All patients underwent successful hybrid recanalization. There were no cases of postoperative stroke or death. Only two patients sustained hoarseness, but it resolved within 2 weeks after surgery. Three patients were treated with dual antiplatelet (aspirin and clopidogrel), seven with single antiplatelet (aspirin), one with single antiplatelet (clopidogrel), and one with single antiplatelet (ticagrelor). All patients were followed up in the outpatient department according to the protocol, with a mean follow-up period of 13 months (range, 6-24 months). No death or recurrent symptoms occurred during the regular follow-up period. Conclusion : The hybrid technique maybe a safe and feasible treatment option to recanalize in-stent restenosis or occlusion with acceptable complications.

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.

Severe, recurrent in-stent carotid restenosis: endovascular approach, risk factors. Results from a prospective academic registry of 2637 consecutive carotid artery stenting procedures (TARGET-CAS)

Introduction

Optimal management of severe carotid in-stent restenosis remains unknown. Prevalence and risk factors of first and recurrent carotid in-stent restenosis in the multi-stent approach have not been established yet.

Aim

To evaluate the safety of different methods of endovascular treatment of carotid in-stent restenosis/recurrent restenosis and to establish its rate and risk factors.

Material and methods

Between January 2001 and June 2016, 2637 neuroprotected carotid artery stenting (CAS) procedures were performed in 2443 patients (men: 67.0%; mean age: 67.9 ±8.8 years, symptomatic: 45.5%). Doppler ultrasound (DUS) evaluation was performed at discharge, after 3-6 months, 12 months, and then annually. Peak systolic velocity of 2-3 and > 3.0 m/s as well as end diastolic velocity of 0.5-0.9 and > 0.9 m/s were DUS criteria for 50-69% and ≥ 70% carotid in-stent restenosis (ISR) respectively. For angiographically confirmed ≥ 70% stenosis balloon re-angioplasty was first line treatment.

Results

Out of 95 DUS detected > 50% ISR (95/2637; 3.6%), 53 were confirmed in angiography as ≥ 70% (53/2637; 2.0%, one total occlusion). All patients were treated with bare balloon (n = 19), drug-eluting balloon (n = 27) or stent-supported (n = 6) angioplasty. One procedure was complicated with stroke (1.9%). Angiographic diameter stenosis (DS) was reduced from 83 ±8.3% to 13 ±7.6% (p < 0.001). There were 13 cases of ≥ 70% recurrent ISR. Bilateral and high-grade stenosis were independent risk factors of restenosis. Initial Carotid Wallstent implantation was a risk factor of first and recurrent in-stent restenosis.

Conclusions

Endovascular treatment of carotid in-stent restenosis is safe. Bilateral and high-grade carotid artery stenosis may increase the risk of restenosis. Initial Carotid Wallstent implantation may increase the risk of first and recurrent restenosis.

Inhibition of Neointima Hyperplasia, Inflammation, and Reactive Oxygen Species in Balloon-Injured Arteries by HVJ Envelope Vector-Mediated Delivery of Superoxide Dismutase Gene

Extracellular superoxide dismutase (EC-SOD) has been implicated in regulation of vascular function but its underlying molecular mechanism is largely unknown. These two-step experiments investigate whether hemagglutinating virus of Japan envelope (HVJ-E) vector-mediated EC-SOD gene delivery might protect against neointima formation, vascular inflammation, and reactive oxygen species (ROS) generation, and also explore cell growth signaling pathways. The first in-vitro experiment was performed to assess the transfection efficacy and safety of HVJ-E compared to lipofectamine®. Results revealed that HVJ-E has higher transfection efficiency and lower cytotoxicity than those of lipofectamine®. Another in-vivo study initially used balloon denudation to rat carotid artery, then delivered EC-SOD cDNA through the vector of HVJ-E. Arterial section with H&E staining from the animals 14 days after balloon injury showed a significant reduction of intima-to-media area ratio in EC-SOD transfected arteries when compared with control (empty vector-transfected arteries) (p < 0.05). Arterial tissue with EC-SOD gene delivery also exhibited lower levels of ROS, as assessed by fluorescent microphotography with dihydroethidium staining. Quantitative RT-PCR revealed that EC-SOD gene delivery significantly diminished mRNA expression of tumor necrosis factor (TNF)-α and interleukin (IL)-1β (p < 0.05 in all comparisons). An immunoblotting assay from vascular smooth muscle cell (VSMC) cultures showed that the EC-SOD transfected group attenuated the activation of MEK1/2, ERK1/2, and Akt signaling significantly. In conclusion, EC-SOD overexpression by HVJ-E vector inhibits neointima hyperplasia, inflammation, and ROS level triggered by balloon injury. The modulation of cell growth-signaling pathways by EC-SOD in VSMCs might play an important role in these inhibitory effects.

Carotid Geometry as a Predictor of In-Stent Neointimal Hyperplasia - A Computational Fluid Dynamics Study

BACKGROUND

Carotid angioplasty and stenting (CAS) is emerging as an alternative treatment for carotid stenosis, but neointimal hyperplasia (NIH) remains a drawback of this treatment strategy. This study aimed to evaluate the effect of variations of carotid bifurcation geometry on local hemodynamics and NIH.Methods and Results:Hemodynamic and geometric effects on NIH were compared between 2 groups, by performing computational fluid dynamics (CFD) simulations both on synthetic models and patient-specific models. In the idealized models, multiple regression analysis revealed a significant negative relationship between internal carotid artery (ICA) angle and the local hemodynamics. In the patient-derived models, which were reconstructed from digital subtraction angiography (DSA) of 25 patients with bilateral CAS, a low time-average wall shear stress (TAWSS) and a high oscillatory shear index (OSI) were often found at the location of NIH. Larger difference values of the OSI percentage area (10.56±20.798% vs. -5.87±18.259%, P=0.048) and ECA/CCA diameter ratio (5.64±12.751% vs. -3.59±8.697%, P=0.047) were detected in the NIH-asymmetric group than in the NIH-symmetric group.

CONCLUSIONS

Changes in carotid bifurcation geometry can make apparent differences in hemodynamic distribution and lead to bilateral NIH asymmetry. It may therefore be reasonable to consider certain geometric variations as potential local risk factors for NIH.

Neointimal formation after carotid artery stenting: phantom and clinical evaluation of model-based iterative reconstruction (MBIR)

OBJECTIVES

The objective of this study was to investigate the usefulness of model-based iterative reconstruction (IR) for detecting neointimal formations after carotid artery stenting.

METHODS

In a cervical phantom harbouring carotid artery stents, we placed simulated neointimal formations measuring 0.40, 0.60, 0.80 and 1.00 mm along the stent wall. The thickness of in-stent neointimal formations was measured on images reconstructed with filtered-back projection (FBP), hybrid IR (AIDR 3D), and model-based IR (FIRST). The clinical study included 43 patients with carotid stents. Cervical computed tomography (CT) images obtained on a 320-slice scanner were reconstructed with AIDR 3D and FIRST. Five blinded observers visually graded the likelihood of neointimal formations on AIDR 3D and AIDR 3D plus FIRST images. Carotid ultrasound images were the reference standard. We analysed results of visual grading by using a Jack-knife type receiver observer characteristics analysis software.

RESULTS

In the phantom study, the difference between the measured and the true diameter of the neointimal formations was smaller on FIRST than FBP or AIDR 3D images. In the clinical study, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of AIDR 3D were 58%, 88%, 83%, 67% and 73%, respectively. For AIDR 3D plus FIRST images they were 84%, 78%, 80%, 82% and 81%, respectively. The mean area under the curve was significantly higher on AIDR 3D plus FIRST than AIDR 3D images (0.82 vs 0.72; p < 0.01).

CONCLUSIONS

The model-based IR algorithm helped to improve diagnostic performance for the detection of neointimal formations after carotid artery stenting.

KEY POINTS

• Neointimal formations can be visualised more accurately with model-based IR. • Model-based IR improves the detection of neointimal formations after carotid artery stenting. • Model-based IR is suitable for follow up after carotid artery stenting.

In-stent hypodense area at two weeks following carotid artery stenting predicts neointimal hyperplasia after two years

Introduction It has not been reported how long the follow-up study after carotid artery stenting (CAS) should be continued. The purpose of the present study is to clarify the dynamic change of the in-stent neointimal layer and residual arterial lumen by two years following CAS using three-dimensional computed tomography angiography (3D CTA) with volume rendering. Methods Thirty-six stented carotid arteries in 34 consecutive patients were examined by 3D CTA with volume rendering at two weeks and 3, 6, 12, 24 months of follow-up. Results An in-stent hypodense area could be detected in 10 of 36 (27.8%) carotid arteries at two weeks after CAS. In-stent hypodense areas gradually declined thereafter by three months. In the course of longer follow-up, the layer of the in-stent hypodense area (neointimal hyperplasia) continued to grow in size for up to 24 months. Patients with an in-stent hypodense area at two weeks have a thicker layer of neointimal hyperplasia at 24 months than patients without in-stent hypodense area at two weeks' follow-up. The predictive factors for growing neointimal hyperplasia at 24 months in multiple regression analysis are ulcer formation in pretreatment stenosis and the thickness of in-stent hypodense area at two weeks following CAS. Conclusion Our results suggest that follow-up study should be continued for a longer period even if in-stent restenosis could not be detected at one year following CAS. Especially in cases with ulcer formation in pretreatment stenosis and with a subacute in-stent hypodense area after CAS, longer follow-up is strongly recommended.

Impact of Hypertriglyceridemia on Carotid Stenosis Progression under Normal Low-Density Lipoprotein Cholesterol Levels

BACKGROUND

Dyslipidemia is a well-known risk factor for carotid stenosis progression, but triglycerides have attracted little attention. The aim of this study was to assess if serum triglycerides affect progression of carotid stenosis in patients with well-controlled low-density lipoprotein cholesterol (LDL-C) levels.

METHODS

This is a retrospective study in a single hospital consisting of 71 Japanese patients with internal carotid artery stenosis greater than or equal to 50% and normal serum LDL-C levels who underwent angiographic examination with or without the resultant carotid artery stenting or endarterectomy from 2007 to 2011, and were subsequently followed up for 4 years. Clinical factors including fasting serum triglyceride values were compared between the progression (≥10% increase in degree of carotid stenosis on ultrasonography) and the nonprogression groups.

RESULTS

During 4 years, 15 patients (21.1%) had carotid stenosis progression on either side. Cox regression analysis demonstrated that symptomatic cases (hazard ratio [HR], 4.327; P = .019), coexisting intracranial arteriosclerotic stenosis (HR, 5.341; P = .005), and hypertriglyceridemia (HR, 6.228; P = .011) were associated with subsequent progression of carotid stenosis. Kaplan-Meier plots demonstrated that the progression-free survival rate was significantly higher in patients without hypertriglyceridemia and intracranial arteriosclerotic stenosis at baseline.

CONCLUSIONS

Among patients with moderate to severe carotid stenosis and well-controlled LDL-C, hypertriglyceridemia was an important risk factor for progression of carotid stenosis irrespective of surgical treatments. It would be worthwhile to test if triglyceride-lowering medications suppress carotid stenosis progression.

Systemically administered collagen-targeted gold nanoparticles bind to arterial injury following vascular interventions

Surgical and endovascular therapies for severe atherosclerosis often fail due to the development of neointimal hyperplasia and arterial restenosis. Our objective was to synthesize, characterize, and evaluate the targeting specificity and biocompatibility of a novel systemically injected nanoparticle. We hypothesize that surface-functionalization of gold nanoparticles (AuNPs) with a collagen-targeting peptide will be biocompatible and target specifically to vascular injury. 13 nm AuNPs were surface functionalized with a peptide-molecular fluorophore and targeted to collagen (T-AuNP) or a scrambled peptide sequence (S-AuNP). After rat carotid artery balloon injury and systemic injection of T-AuNP or S-AuNP, arteries and organs were harvested and assessed for binding specificity and biocompatibility. The T-AuNP bound with specificity to vascular injury for a minimum of 24 h. No significant inflammation was evident locally at arterial injury or systemically in major organs. The T-AuNP did not impact endothelial cell viability or induce apoptosis at the site of injury in vivo. No major changes were evident in hepatic or renal blood chemistry profiles. Herein, we synthesized a biocompatible nanoparticle that targets to vascular injury following systemic administration. These studies demonstrate proof-of-principle and serve as the foundation for further T-AuNP optimization to realize systemic, targeted delivery of therapeutics to the sites of vascular injury.

Intracerebral Hemorrhage Caused by Cerebral Hyperperfusion after Superficial Temporal Artery to Middle Cerebral Artery Bypass for Atherosclerotic Occlusive Cerebrovascular Disease

Few papers have reported detailed accounts of intracerebral hemorrhage caused by cerebral hyperperfusion after superficial temporal artery to middle cerebral artery bypass (STA-MCA) bypass for atherosclerotic occlusive cerebrovascular disease. We report a case of vasogenic edema and subsequent intracerebral hemorrhage caused by the cerebral hyperperfusion syndrome (CHS) after STA-MCA bypass for atherosclerotic occlusive cerebrovascular disease disease without intense postoperative blood pressure control. A 63-year-old man with repeating left hemiparesis underwent magnetic resonance angiography (MRA), which revealed right internal carotid artery (ICA) occlusion. We performed a double bypass superficial temporal artery (STA)–middle cerebral artery (MCA) bypass surgery for the M2 and M3 branches. While the patient’s postoperative course was relatively uneventful, he suffered generalized convulsions, and computed tomography revealed a low area in the right frontal lobe on Day 4 after surgery. We considered this lesion to be pure vasogenic edema caused by cerebral hyperperfusion after revascularization. Intravenous drip infusion of a free radical scavenger (edaravone) and efforts to reduce systolic blood pressure to <120 mmHg were continued. The patient experienced severe left hemiparesis and disturbance of consciousness on Day 8 after surgery, due to intracerebral hemorrhage in the right frontal lobe at the site of the earlier vasogenic edema. Brain edema associated with cerebral hyperperfusion after STA-MCA bypass for atherosclerotic occlusive cerebrovascular disease should be recognized as a risk factor for intracerebral hemorrhage. The development of brain edema associated with CHS after STA-MCA bypass for atherosclerotic occlusive cerebrovascular disease requires not only intensive control of blood pressure, but also consideration of sedation therapy with propofol.

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.

Targeting collagen for diagnostic imaging and therapeutic delivery

As the most abundant protein in mammals and a major structural component in extracellular matrix, collagen holds a pivotal role in tissue development and maintaining the homeostasis of our body. Persistent disruption to the balance between collagen production and degradation can cause a variety of diseases, some of which can be fatal. Collagen remodeling can lead to either an overproduction of collagen which can cause excessive collagen accumulation in organs, common to fibrosis, or uncontrolled degradation of collagen seen in degenerative diseases such as arthritis. Therefore, the ability to monitor the state of collagen is crucial for determining the presence and progression of numerous diseases. This review discusses the implications of collagen remodeling and its detection methods with specific focus on targeting native collagens as well as denatured collagens. It aims to help researchers understand the pathobiology of collagen-related diseases and create novel collagen targeting therapeutics and imaging modalities for biomedical applications.

In-Stent Restenosis After Carotid Artery Stenting: From Diagnosis to Treatment

Although carotid artery stenting is a safe and effective treatment for preventing ischaemic stroke in significant carotid atherosclerotic disease, it can be complicated by in-stent restenosis (ISR). Factors involved in the ISR process are both mechanical and patient-related, but the most important is the neointimal thickening within stent struts, leading to lumen reduction. Overall incidence of carotid ISR is low and related embolic risk seems to be lower than native disease. Digital subtraction angiography is the gold standard for diagnosis. Nowadays, Doppler ultrasound should be considered the first-line investigation, due to its non-invasiveness and reproducibility. Computed tomography angiography remains useful when Doppler ultrasound is inconclusive. Indication and modality of treatment of ISR are still debated: both surgery (carotid endarterectomy with stent removal in most cases) or interventional procedures such as percutaneous transluminal angioplasty with simple balloon, cutting-balloon, drug-eluting balloon, and stenting, showed safety and efficacy in follow-up. Surgery is currently reserved for selected cases. Carotid ISR is an overall rare complication which can be easily identified at routine follow-up. This paper is a literature review and state-of-the-art assessment of ISR, clinical features, diagnosis, and treatment.

Diagnostic vascular ultrasonography with the help of color Doppler and contrast-enhanced ultrasonography

The use of ultrasonography and especially of contrast-enhanced ultrasonography (CEUS) in the diagnosis of vascular pathologies before and after interventions has significantly increased over the past years due to the broader availability of modern ultrasound systems with CEUS capabilities and more trained user experience in this imaging modality. For the preinterventional and postinterventional work-up of carotid diseases, duplex ultrasound as well as CEUS have been established as the standard-of-care examination procedures for diagnosis, evaluation, and follow-up. In addition to its use for carotid arterial diseases, ultrasonography has also become the primary modality for the screening of vascular pathologies. This review describes the most common pathologies found in ultrasonography of the carotid arteries, the abdominal aorta, and the femoral arteries.

CT Angiography of Stented Carotid Arteries: Comparison with Doppler Ultrasonography

Purpose:

To determine whether computed tomographic angiography (CTA) is a feasible modality for assessing stented carotid arteries and whether in-stent restenosis based on CTA concurs with ultrasonography (US).

Methods:

A retrospective review was conducted of 37 follow-up CTA and US images from 27 patients (23 men; median age 70 years, range 56–77) who received 34 nitinol carotid stents. CTA and US images were compared with respect to assessability and percent stenosis. Both visual estimation (≥50% or not) and the NASCET method were used to determine percent stenosis in CTA images. For US, a determination of ≥50% stenosis was based on peak systolic velocity (≥200 cm/s) and an internal carotid artery to common carotid artery ratio ≥2.5. Percent stenosis values by CTA were also compared to values (n=7, 21%) determined by catheter angiography.

Results:

CTA and US images were “totally assessable” in 27 (73%) and 15 (41%), “totally non-assessable” in 0 (0%) and 3 (8%), and “partially assessable” in 10 (27%) and 19 (51%), respectively. Assessability of CTA images was equal to or better than that of US images in 33 (89%). The percent stenoses by CTA and US were comparable in 20 cases. CTA found ≥50% stenosis using the NASCET method in 4 of 20 stents; none of these showed ≥50% stenosis by visual estimation of CTA or by spectral Doppler US. Compared with catheter angiography, CTA overestimated percent stenosis from 34% to 66% (mean 53%). US confirmed 2 angiographically proven restenoses, but CTA identified only 1.

Conclusion:

CTA provides better image quality for stented carotid arteries than US, but it might be inferior to US in determining restenosis in assessable cases. Therefore, CTA is likely to be an alternative to US in cases of non-assessability. A large-scale study including more restenosis cases is warranted to reveal which modality is more reliable for diagnosis of restenosis.

Meta-Analysis of Studies Evaluating the Effect of Cilostazol on Major Outcomes After Carotid Stenting

PURPOSE

To evaluate the effect of cilostazol on major outcomes after carotid artery stenting (CAS).

METHODS

A systematic literature review was conducted conforming to established criteria in order to identify articles published prior to May 2015 evaluating major post-CAS outcomes in patients treated with cilostazol vs patients not treated with cilostazol. Major outcomes included in-stent restenosis (ISR) within the observation period, the revascularization rate, major/minor bleeding, and the myocardial infarction/stroke/death rate (MI/stroke/death) at 30 days and within the observation period. Data were pooled for all studies containing adequate data for each outcome investigated; effect estimates are presented as the odds ratios (ORs) and 95 confidence intervals (CI).

RESULTS

Overall, 7 studies pertaining to 1297 patients were eligible. Heterogeneity was low among studies so a fixed-effect analysis was conducted. Six studies (n=1233) were compared for the ISR endpoint, showing a significantly lower ISR rate with cilostazol treatment after a mean follow-up of 20 months (OR 0.158, 95% CI 0.072 to 0.349, p<0.001). Five studies (n=649) were compared regarding 30-day MI/stroke/death (OR 0.724, 95% CI 0.293 to 1.789, p=0.484) and 3 studies (n=1076) were analyzed regarding MI/stroke/death within the entire follow-up period (OR 0.768, 95% CI 0.477 to 1.236, p=0.276); no significant difference was found between the groups. Data on bleeding rates and revascularization rates post ISR were inadequate to conduct further analysis.

CONCLUSION

Cilostazol seems to decrease total ISR rates in patients undergoing CAS without affecting MI/stroke/death events, both in the early and late settings.

Predictors of restenosis after carotid artery stenting in 241 cases

Background

Variable rates of restenosis after carotid artery stenting (CAS) have been reported, and few predictors have been suggested. Because CAS is being performed with increasing frequency, more data are needed to evaluate the rate and predictors of restenosis and possibly identify new risk factors for restenosis after CAS. The aim of this study was to analyze the rate and predictors of restenosis after CAS.

Methods

241 patients with carotid artery stenosis treated with stenting were analyzed retrospectively to identify patients who had restenosis after stenting. Univariate analysis and multivariate logistic regression were conducted to determine the predictors of restenosis.

Results

Mean patient age was 67.5 years. 8.3% of patients who underwent CAS had carotid restenosis of ≥50% during follow-up. 3.7% of patients required retreatment. Mean duration from CAS to retreatment was 11 months. In multivariate analysis, the predictors of restenosis included history of cardiovascular disease (OR=8.88, p<0.001) and having a cerebrovascular accident (CVA) prior to stenting (OR=1.87, p=0.034). A higher percentage of preoperative carotid stenosis was associated with higher odds of restenosis in univariate analysis (p=0.04, OR stenosis ≥80%=5.7).

Conclusions

Our results suggest that the rate of carotid restenosis after stenting is low. Patients with cardiovascular disease, patients who had a CVA prior to stenting, and patients with higher percentages of preoperative stenosis had higher odds of restenosis. Higher rates of restenosis should be kept in mind when opting for CAS in these patients.

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

Shape-Dependent Targeting of Injured Blood Vessels by Peptide Amphiphile Supramolecular Nanostructures

Targeting of vascular intervention by systemically delivered supramolecular nanofibers after balloon angioplasty is described. Tracking of self-assembling peptide amphiphiles using fluorescence shows selective binding to the site of vascular intervention. Cylindrical nanostructures are observed to target the site of arterial injury, while spherical nanostructures with an equivalent diameter display no binding.

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.

Optimal ultrasound criteria for defining the severity of vertebral artery in-stent restenosis

The aim of the study described here was to establish ultrasound criteria for defining the severity of vertebral artery in-stent restenosis. A total of 197 patients with vertebral artery stents were enrolled in this study. Color Doppler ultrasonography was performed after stenting. Peak systolic velocity and end-diastolic velocity within the stent (PSV(stent), EDV(stent)) and at the intervertebral segments were recorded. The ratio of the PSV at the origin to that at the intervertebral segment was calculated. With digital subtraction angiography as the reference standard, the optimal cutoff values of hemodynamic parameters identifying 50%-69% and 70%-99% restenosis were determined by receiver operating characteristic analysis. The optimal cutoff values of hemodynamic parameters identifying 50%-69% restenosis were PSV(stent) ≥ 170 cm/s, EDV(stent) ≥45 cm/s and PSV ratio ≥2.7, and those for 70%-99% restenosis were PSV(stent) ≥220 cm/s, EDV(stent) ≥55 cm/s and PSV ratio ≥4.2. In conclusion, color Doppler ultrasonography is a reliable method for monitoring patients with avertebral artery stents.

Valsartan prevents neointimal hyperplasia after carotid artery stenting by suppressing endothelial cell injuries

OBJECTIVES

Restenosis or neointimal hyperplasia remains an important complication after carotid artery stenting (CAS) for carotid artery stenosis. The purpose of this study was to examine if an anti-hypertensive drug, angiotensin receptor blocker (ARB), prevents post-CAS neointimal hyperplasia during the first 1-year period after CAS, and to clarify the possible mechanisms.

METHODS

Hypertension had been treated with a calcium channel blocker (CCB) and/or an ARB, valsartan, by the preference of the neurosurgeon in charge in our department. At admission to perform CAS, patients were assigned to normotensive, valsartan (hypertensive patients treated with valsartan with/without any kind of CCBs), and non-valsartan (hypertensive patients treated with any kind of CCBs without ARBs) groups. Post-CAS neointimal hyperplasia was evaluated by carotid duplex ultrasound imaging in terms of intima-media thickening (IMT), which was performed at pre-CAS and at 90, 180, 270, and 360 days post-CAS. Biomarkers of oxidative stress (8-hydroxy-2'-deoxyguanosine), inflammation (C-reactive protein, tenascin-C) and endothelial cell injury (von Willebrand factor [vWF] antigen) were measured at pre-CAS and at 1, 7, and 180 days post-CAS.

RESULTS

The non-valsartan group (n  =  8) had a higher incidence of maximum in-stent IMT ≧ 1.1 mm compared with the normotensive group (n  =  6). Valsartan (n  =  9) significantly suppressed plasma vWF levels at 7 days post-CAS and decreased the incidence of maximum in-stent IMT ≧ 1.1 mm compared with the non-valsartan group, although clinical parameters were similar between the two groups. Other biomarkers were not significantly different among the three groups.

CONCLUSIONS

These findings suggest that valsartan may prevent post-CAS neointimal hyperplasia possibly by suppressing endothelial cell injury.

Argatroban for preventing occlusion and restenosis after extracranial artery stenting

BACKGROUND/AIMS

Restenosis following extracranial artery stenting is a limitation that affects long-term outcomes. Effective and satisfying pharmacological strategies in preventing restenosis have not been established. This study aimed to evaluate whether argatroban, a direct thrombin inhibitor, could reduce the risk of in-stent restenosis after extracranial artery stenting.

METHODS

One hundred and fourteen patients hospitalized between August 2010 and August 2011 were enrolled. Patients were randomly assigned to argatroban (n = 58) and blank control groups (n = 56). The patients in the argatroban arm were treated with 10 mg of intravenous argatroban twice daily 2 days before and 3 days after the stenting procedures. Patients were followed for 12 months after the procedure. During follow-up, restenosis and target revascularization were analyzed. Recurrent cerebrovascular and cardiovascular events and deaths were also compared between the groups.

RESULTS

One patient in the stenting group withdrew immediately after the procedure due to unsuccessful stenting. Restenosis occurred in 4 patients (7.4%) in the argatroban group and in 11 patients (21.6%) in the control group during the 6- to 9-month angiographic follow-up period (p = 0.032). Nine months after the procedures, argatroban-treated patients had a trend towards a lower incidence of target revascularization compared with the controls (5.4 vs. 13.7%, p = 0.188). No major bleeding events or other adverse events occurred in the argatroban group.

CONCLUSION

This pilot clinical trial is the first that uses argatroban to prevent restenosis in ischemic cerebrovascular disease, and suggests that intravenous administration of argatroban is effective and safe in preventing restenosis after extracranial artery stenting. Larger randomized controlled clinical trials are warranted.

An agent-based model of the response to angioplasty and bare-metal stent deployment in an atherosclerotic blood vessel

PURPOSE

While animal models are widely used to investigate the development of restenosis in blood vessels following an intervention, computational models offer another means for investigating this phenomenon. A computational model of the response of a treated vessel would allow investigators to assess the effects of altering certain vessel- and stent-related variables. The authors aimed to develop a novel computational model of restenosis development following an angioplasty and bare-metal stent implantation in an atherosclerotic vessel using agent-based modeling techniques. The presented model is intended to demonstrate the body's response to the intervention and to explore how different vessel geometries or stent arrangements may affect restenosis development.

METHODS

The model was created on a two-dimensional grid space. It utilizes the post-procedural vessel lumen diameter and stent information as its input parameters. The simulation starting point of the model is an atherosclerotic vessel after an angioplasty and stent implantation procedure. The model subsequently generates the final lumen diameter, percent change in lumen cross-sectional area, time to lumen diameter stabilization, and local concentrations of inflammatory cytokines upon simulation completion. Simulation results were directly compared with the results from serial imaging studies and cytokine levels studies in atherosclerotic patients from the relevant literature.

RESULTS

The final lumen diameter results were all within one standard deviation of the mean lumen diameters reported in the comparison studies. The overlapping-stent simulations yielded results that matched published trends. The cytokine levels remained within the range of physiological levels throughout the simulations.

CONCLUSION

We developed a novel computational model that successfully simulated the development of restenosis in a blood vessel following an angioplasty and bare-metal stent deployment based on the characteristics of the vessel cross-section and stent. A further development of this model could ultimately be used as a predictive tool to depict patient outcomes and inform treatment options.

The role of contrast-enhanced ultrasound in imaging carotid arterial diseases

The standard of care for the initial diagnosis of carotid artery bifurcation diseases is carotid duplex ultrasound. Carotid abnormalities or difficult examinations may represent a diagnostic challenge in patients with clinical symptoms as well as in the follow-up after carotid endarterectomy, carotid artery stenting or other interventions. A promising new method in the diagnosis and follow-up of pathologic carotid diseases is contrast-enhanced ultrasound (CEUS). In comparison with magnetic resonance imaging or computed tomography, the contrast agents used for CEUS remain within the vascular space and hence can be used to study vascular disease and could provide additional information on carotid arterial diseases. This review describes the current carotid duplex ultrasound examination and compares the pathologic findings with CEUS.

Complications and Solutions with Carotid Stenting

Complications of carotid stenting can be classified as neurologic, cardiovascular, death, carotid, access site, device malfunctions, and general and late complications. The risk of most complications is related to readily identifiable patient and anatomic factors. Management and outcome of complications require immediate recognition and a team-based approach to patient care.

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.

The durability of carotid endarterectomy: long-term results for restenosis and stroke

BACKGROUND

Carotid endarterectomy is a low-risk treatment for carotid occlusive disease. Recent clinical trials have suggested that carotid angioplasty may be a viable alternative. One important issue that has not been evaluated is the long-term recurrent stenosis rate after either intervention.

OBJECTIVE

To examine the risk of recurrent stenosis after carotid endarterectomy and to provide long-term data on the durability of carotid endarterectomy.

METHODS

A total of 1335 sequential patients were followed up prospectively with annual carotid ultrasonography. All patients were maintained on antiplatelet therapy, and arteriotomies were closed with a patch graft. Operations were performed under general anesthesia with electroencephalographic monitoring and selective shunting. There were no changes in surgical technique during this study.

RESULTS

Two-thirds of the patients were men; the mean age was 70 years. Approximately 60% were symptomatic. The 90-day perioperative morbidity and mortality rate was 0.9% (0.4% stroke and 0.5% death). Five patients (0.4%) developed recurrent stenosis >70% over a mean follow-up of 15.8 years. Twelve patients (0.9%) had documentation of late stroke in the ipsilateral carotid distribution. The mean follow-up was 15.8 years.

CONCLUSION

Carotid endarterectomy is an extremely safe treatment for carotid stenosis with very low perioperative complications and low rates of recurrent stenosis or late stroke. When endarterectomy is compared with angioplasty, in addition to periprocedural complications, the durability of both interventions needs to be considered, given the risks and costs of repeat interventions.

Carotid artery stenting without post-stenting balloon dilatation

PURPOSE

To evaluate the clinical outcome and MRI findings after carotid artery stenting (CAS) without post-dilatation.

METHODS

Between May 2005 and April 2012, a total of 169 consecutive patients (61.4% symptomatic) underwent 176 CAS procedures performed with an embolic protection device (GuardWire, n=116; FilterWire EZ, n=60). All stents were deployed without post-dilatation. Periprocedural complications and mid-term outcomes were analyzed.

RESULTS

The stroke rate was 2.3% within 30 days post-CAS (asymptomatic patients 1.5%; symptomatic patients 2.8%). Cerebral infarction occurred in one asymptomatic patient (1.5%) and one symptomatic patient (0.9%). Intracranial hemorrhage occurred in two symptomatic patients (1.9%). Post-CAS diffusion-weighted imaging (DWI) revealed a high-intensity area in 26 of 176 procedures (14.8%). Ipsilateral stroke after 31 days occurred in two patients (1.1%) and restenosis occurred in six (3.4%). A post-CAS comparison of the embolic protection devices revealed no difference in stroke incidence within 30 days and in DWI high-intensity area.

CONCLUSIONS

Our CAS procedure without post-dilatation is feasible, safe and associated with a low incidence of stroke and restenosis.

Patient-specific finite element analysis of carotid artery stenting: a focus on vessel modeling

Finite element analysis is nowadays a well-assessed technique to investigate the impact of stenting on vessel wall and, given the rapid progression of both medical imaging techniques and computational methods, the challenge of using the simulation of carotid artery stenting as procedure planning tool to support the clinical practice can be approached. Within this context, the present study investigates the impact of carotid stent apposition on carotid artery anatomy by means of patient-specific finite element analysis. In particular, we focus on the influence of the vessel constitutive model on the prediction of carotid artery wall tensional state of lumen gain and of vessel straightening. For this purpose, we consider, for a given stent design and CA anatomy, two constitutive models for the CA wall, that is, a hyperelastic isotropic versus a fiber-reinforced hyperelastic anisotropic model. Despite both models producing similar patterns with respect to stress distribution, the anisotropic model predicts a higher vessel straightening and a more evident discontinuity of the lumen area near the stent ends as observed in the clinical practice. Although still affected by several simplifications, the present study can be considered as further step toward a realistic simulation of carotid artery stenting.

Indications for treatment of recurrent carotid stenosis

Background

There is significant variation in the indications for intervention in patients with recurrent carotid artery stenosis. The aim of the present study was to describe these indications in a contemporary cohort of patients.

Methods

This was a systematic review of all peer-reviewed studies reporting on the indications for carotid intervention in patients with recurrent stenosis after carotid endarterectomy (CEA) or carotid artery stenting (CAS) that were published between 1990 and 2012.

Results

There were 50 studies reporting on a total of 3524 patients undergoing a carotid procedure; of these, 3478 underwent CEA as the initial intervention. Reintervention was by CEA in 2403 patients and by CAS in 1121. Only 54·7 per cent of the patients were treated for any symptoms and, importantly, just 444 (23·1 per cent of 1926 symptomatic patients) underwent intervention for documented ipsilateral symptoms. None of the studies reported whether the patients were evaluated for other sources of emboli. The remaining 45·3 per cent of patients had asymptomatic restenosis and in the majority of the studies were treated when the degree of stenosis exceeded 80 per cent. The time to repeat intervention was significantly longer in patients with recurrent atherosclerosis, in asymptomatic patients and in patients undergoing CEA.

Conclusion

The reported criteria for retreatment of carotid stenosis were not rigorous and there is still significant ambiguity surrounding the indications for intervention.

Zotarolimus-eluting stent for the treatment of recurrent, severe carotid artery in-stent stenosis in the TARGET-CAS population

PURPOSE

To evaluate the safety and efficacy of a balloon-mounted drug-eluting stent (DES) for recurrent carotid in-stent stenosis (ISS).

METHODS

As part of our targeted carotid artery stenting (TARGET-CAS) protocol, neurological and ultrasound evaluations have been performed at 3, 6, and 12 months and then annually since 2001 in all carotid stent patients. For angiographically-confirmed >70% ISS, balloon angioplasty was performed as a first-line treatment. Recurrent ISS was treated with a 4.0-mm zotarolimus-eluting coronary stent (ZES) that was postdilated according to intravascular ultrasound imaging. Among the 1350 neuroprotected CAS procedures performed between January 2001 and March 2011, there were 7 (0.52%) patients (5 men; ages 51-72 years), all neurologically asymptomatic, with >70% recurrent ISS that occurred at 5 to 11 months after the initial balloon angioplasty treatment for ISS.

RESULTS

ZES implantation under distal embolic protection was technically successful and uncomplicated. Angiographic stenosis was reduced from 84.6%±7.5% to 10.7%±3.6% (p<0.01). In 5 patients with ZES implanted fully within the self-expanding carotid stent, duplex ultrasound follow-up (mean 17 months, range 6-36) revealed no evidence of restenosis or stent fracture/deformation. In the 2 other patients, the ZES had been implanted for distal edge ISS such that the ZES protruded beyond the original carotid stent. This protruding segment of the ZES demonstrated deformation/kinking in both; in one, this led to symptomatic stent occlusion.

CONCLUSION

The use of coronary ZES in the treatment of recurrent carotid ISS is feasible and appears effective provided the ZES is placed entirely within the original stent. Placement of a coronary ZES outside the carotid stent scaffold should be avoided.

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.

Long-term outcome in patients with carotid artery stenting and contralateral carotid occlusion: a single neurovascular center prospective analysis

INTRODUCTION

The aim of this study was to analyze the clinical features and early and late outcome of patients treated with carotid artery stenting for carotid stenosis with occlusion of the contralateral vessel (CAS-CCO), and compare them to patients without occlusion (CAS-NO).

METHODS

From 1999 through 2010, 426 patients with 479 procedures were prospectively recorded, 61 patients (14.3%) CAS-CCO, and 365 patients CAS-NO. Immediate CAS complications, complications within the first 30 days and long-term complications were documented through annual clinical and ultrasonological follow-up visits. Stenosis rate was recorded.

RESULTS

Patients with mean age of 68.4 years, 80% men had: (1) periprocedural stroke in three cases (0.7%), (2) cumulative 30-day stroke, ischemic cardiopathy, and death in 4.2%, without differences between groups (CAS-CCO 3.3%, CAS-NO 4.4%). Mean follow-up period was 55 ± 32.78 months, median 56 months. (3) Stroke during the follow-up in 8%, without differences between CAS-CCO and CAS-NO groups (3.7% and 8.8%). (4) Myocardial infarction in 11.2% and (5) global mortality in 24.3%, without statistical differences between groups. Of the 254 cases enrolled in the restenosis analysis, 44 patients (17.3%) had restenosis of any grade during a mean follow-up period of 52 months, without statistical differences between CAS-CCO and CAS-NO groups. Only 7.5% presented restenosis ≥ 50%. Its occurrence was statistically associated with previous neck radiation.

CONCLUSIONS

Periprocedural risks and long-term outcomes of patients treated with CAS and presenting a contralateral carotid occlusion does not differ from regular patients treated with CAS. Based on the low stenosis rate of our study, our results do not give credit to extra surveillance measures in patients with contralateral carotid occlusion.