Long-Term Results of Carotid Artery Stents to Manage Symptomatic Carotid Artery Stenosis and Factors That Affect Outcome

The role of post-dilatation in carotid MicroNet-covered stent implantation, evaluated using 3D cone-beam CT angiography

BACKGROUND

This study aims to assess the role and safety of post-dilatation in protected carotid artery stenting (PCAS) using the new MicroNet-covered 2nd-generation stent assessed by cone beam CT scans.

METHODS

From March 2020 to March 2022, patients were enrolled in the study according to CT angiography results based on the following criteria: Evidence of 70% to 99% carotid stenosis in asymptomatic patients and 50% to 99% in symptomatic patients, per the NASCET index. Using a FilterWire EZ™ (Boston Scientific, Natick, MA, USA) embolic protection system (EPS), MicroNet-covered stent PCAS was performed by two interventional radiologists with at least 8 years of experience in endovascular intervention. Each patient underwent post-dilatation following stent placement. Finally, a third radiologist (not participating in the interventional procedures) evaluated the cone beam CT scans and calculated residual stenosis. Major and minor complications were recorded in the 30 days following the procedure.

RESULTS

A total of 192 patients (121 male, mean age 73±10 years) were included in the study, and all patients received post-dilatation following stent implantation. Technical successes were achieved in all procedures. Adverse events noted in this study were limited to periprocedural transient ischemic attacks that occurred in three out of 192 patients (1.6%) and showed a swift complete recovery. The post-dilatation balloon diameters used in the study were: 5.0 mm (30.3%), 5.5 mm (39.3%) and 6 mm (30.3%). Optimized postdilatation resulted in a significant increase in the final luminal area. Similar improvements were observed in all subtypes of plaque.

CONCLUSIONS

Post-dilatation in protected CAS is safe and induces a significant improvement in the cross-sectional area regardless of the stenotic plaque.

Usefulness of cone-beam computed tomography to predict residual stenosis after carotid artery stenting

OBJECTIVES

The long-term durability of carotid artery stenting (CAS) may be determined by various factors; however, residual stenosis is a known risk factor for in-stent restenosis. The authors of this article utilized cone-beam computed tomography (CBCT) in angiosuite to investigate plaque features affecting the character and quality of stent expansion after CAS.

METHODS

Forty-two CAS cases with both pre- and post-CAS CBCT evaluations were included in this retrospective analysis. Five features derived from pre-CAS images were tested: (1) eccentricity, (2) overballoon, (3) maximum plaque thickness, (4) calcification barrier, and (5) stenotic degree. For post-CAS CBCT, stent configuration was assessed if the stent was expanded and oval or round in shape as well as outward or inward in orientation. Variables were tested if they were associated with oval expansion, outward expansion, and 20% residual stenosis after CAS.

RESULTS

Oval or outward expansion is directly related to residual stenosis. The oval expansion was associated with maximum plaque thickness, and outward expansion was associated with the presence of a calcification barrier. Variables related to > 20% residual stenosis were the maximum plaque thickness, calcification barrier, and pre-CAS stenotic degree.

CONCLUSIONS

CBCT for carotid stenosis may provide valuable information about plaque features, especially calcification features that may interfere with the angioplasty effect, as well as the characteristics and quality of stent expansion. Residual stenosis > 20% was associated with calcification barrier, maximum plaque thickness, and pre-CAS stenotic degree.

Clinical Outcomes of Second- versus First-Generation Carotid Stents: A Systematic Review and Meta-Analysis

Background: Single-cohort studies suggest that second-generation stents (SGS; “mesh stents”) may improve carotid artery stenting (CAS) outcomes by limiting peri- and postprocedural cerebral embolism. SGS differ in the stent frame construction, mesh material, and design, as well as in mesh-to-frame position (inside/outside). Objectives: To compare clinical outcomes of SGS in relation to first-generation stents (FGSs; single-layer) in CAS. Methods: We performed a systematic review and meta-analysis of clinical studies with FGSs and SGS (PRISMA methodology, 3302 records). Endpoints were 30-day death, stroke, myocardial infarction (DSM), and 12-month ipsilateral stroke (IS) and restenosis (ISR). A random-effect model was applied. Results: Data of 68,422 patients from 112 eligible studies (68.2% men, 44.9% symptomatic) were meta-analyzed. Thirty-day DSM was 1.30% vs. 4.11% (p < 0.01, data for SGS vs. FGS). Among SGS, both Casper/Roadsaver and CGuard reduced 30-day DSM (by 2.78 and 3.03 absolute percent, p = 0.02 and p < 0.001), whereas the Gore stent was neutral. SGSs significantly improved outcomes compared with closed-cell FGS (30-day stroke 0.6% vs. 2.32%, p = 0.014; DSM 1.3% vs. 3.15%, p < 0.01). At 12 months, in relation to FGS, Casper/Roadsaver reduced IS (−3.25%, p < 0.05) but increased ISR (+3.19%, p = 0.04), CGuard showed a reduction in both IS and ISR (−3.13%, −3.63%; p = 0.01, p < 0.01), whereas the Gore stent was neutral. Conclusions: Pooled SGS use was associated with improved short- and long-term clinical results of CAS. Individual SGS types, however, differed significantly in their outcomes, indicating a lack of a “mesh stent” class effect. Findings from this meta-analysis may provide clinically relevant information in anticipation of large-scale randomized trials.

Diabetes Mellitus and Clinical Outcomes in Carotid Artery Revascularization Using Second-Generation, MicroNet-Covered Stents: Analysis from the PARADIGM Study

INTRODUCTION

Carotid artery stenting (CAS) using conventional (single-layer) stents is associated with worse clinical outcomes in diabetes mellitus (DM) vs. non-DM patients: an effect driven largely by lesion-related adverse events. CAS outcomes with MicroNet-covered stents (MCS) in diabetic patients have not been evaluated.

AIM

To compare short- and long-term clinical outcomes and restenosis rate in DM vs. non-DM patients with carotid stenosis treated using MCS.

MATERIALS AND METHODS

In a prospective study in all-comer symptomatic and increased-stroke-risk asymptomatic carotid stenosis, 101 consecutive patients (age 51-86 years, 41% diabetics) underwent 106 MCS-CAS. Clinical outcomes and duplex ultrasound velocities were assessed periprocedurally and at 30 days/12 months.

RESULTS

Baseline characteristics of DM vs. non-DM patients were similar except for a higher prevalence of recent cerebral symptoms in DM. Type 1 and type 1+2 plaques were more prevalent in DM patients (26.7% vs. 9.8%, p = 0.02; 62.2% vs. 37.7%, p = 0.01). Proximal embolic protection was more prevalent in DM (60% vs. 36%; p = 0.015). 30-day clinical complications were limited to a single periprocedural minor stroke in DM (2.4% vs. 0%, p = 0.22). 12-month in-stent velocities and clinical outcomes were not different (death rate 4.8% vs. 3.3%; p = 0.69; no new strokes). Restenosis rate was not different (0% vs. 1.7%, p = 0.22).

CONCLUSIONS

MCS may offset the adverse impact of DM on periprocedural, 30-day, and 12-month clinical complications of CAS and minimize the risk of in-stent restenosis. In this increased-stroke-risk cohort, adverse event rate was low both in DM and non-DM. Further larger-scale clinical datasets including extended follow-ups are warranted.

A meta-analysis of the effect of stent design on clinical and radiologic outcomes of carotid artery stenting

OBJECTIVE

Procedural characteristics, including stent design, may influence the outcome of carotid artery stenting (CAS). A thorough comparison of the effect of stent design on outcome of CAS is thus warranted to allow for optimal evidence-based clinical decision making. This study sought to evaluate the effect of stent design on clinical and radiologic outcomes of CAS.

METHODS

A systematic search was conducted in MEDLINE, Embase, and Cochrane databases in May 2018. Included were articles reporting on the occurrence of clinical short- and intermediate-term major adverse events (MAEs; any stroke or death) or radiologic adverse events (new ischemic lesions on postprocedural magnetic resonance diffusion-weighted imaging [MR-DWI], restenosis, or stent fracture) in different stent designs used to treat carotid artery stenosis. Random effects models were used to calculate combined overall effect sizes. Metaregression was performed to identify the effect of specific stents on MAE rates.

RESULTS

From 2654 unique identified articles, two randomized, controlled trials and 66 cohort studies were eligible for analysis (including 46,728 procedures). Short-term clinical MAE rates were similar for patients treated with open cell vs closed cell or hybrid stents. Use of an Acculink stent was associated with a higher risk of short-term MAE compared with a Wallstent (risk ratio [RR], 1.51; P = .03), as was true for use of Precise stent vs Xact stent (RR, 1.55; P < .001). Intermediate-term clinical MAE rates were similar for open vs closed cell stents. Use of open cell stents predisposed to a 25% higher chance (RR, 1.25; P = .03) of developing postprocedural new ischemic lesions on MR-DWI. No differences were observed in the incidence of restenosis, stent fracture, or intraprocedural hemodynamic depression with respect to different stent design.

CONCLUSIONS

Stent design is not associated with short- or intermediate-term clinical MAE rates in patients undergoing CAS. Furthermore, the division in open and closed cell stent design might conceal true differences in single stent efficacy. Nevertheless, open cell stenting resulted in a significantly higher number of subclinical postprocedural new ischemic lesions detected on MR-DWI compared with closed cell stenting. An individualized patient data meta-analysis, including future studies with prospective homogenous study design, is required to adequately correct for known risk factors and to provide definite conclusions with respect to carotid stent design for specific subgroups.

Impact of hospital volume on long-term neurological outcome in patients undergoing carotid artery stenting

BACKGROUND

The impact of hospital volume on long-term outcome after carotid artery stenting (CAS) remains unknown.

OBJECTIVES

We designed a nationwide cohort study to elucidate the impact of hospital volume on the incidence of stroke after CAS.

METHODS

The Taiwan National Health Insurance Research database was used to identify all patients admitted for CAS from 2008 to 2012. We defined high-volume hospitals as those performing more than 20 CAS per year. The primary outcome was new ischemic stroke after discharging from the index CAS. Propensity score-matching was performed to create two matched groups for comparison.

RESULTS

A total of 3,248 patients underwent 3,576 CAS procedures were enrolled. There were 56 hospitals performing CAS during the study period. Among these 3,248 patients, 2,226 (68.5%) were performed in high-volume hospitals. A propensity score-matching created two groups with 1,000 patients in each group. During a median of 2.06 years follow-up, 35 (3.5%) and 52 (5.2%) patients in high-volume hospitals and low-volume hospitals developed new ischemic stroke 30 days after discharging from the index CAS, respectively (for low-volume hospitals, HR 1.50, 95%CI 1.06-2.12, P = 0.023). The use of embolic protection device did not result in different periprocedural or postdischarge strokes. The periprocedural (within 30 days after CAS) ischemic stroke or all-cause mortality rates during follow-up period were similar between two groups.

CONCLUSIONS

CAS performed in high-volume hospitals was associated with less new ischemic stroke after discharging from the index CAS, compared to those in low-volume hospitals. © 2017 Wiley Periodicals, Inc.

Natural History and Management of Blunt Traumatic Pseudoaneurysms of the Internal Carotid Artery: The Harborview Algorithm Based Off a 10-Year Experience

OBJECTIVE

To define the natural history of, and treatment strategy for, blunt traumatic internal carotid artery (ICA) pseudoaneurysms.

BACKGROUND

The natural history and management of traumatic ICA pseudoaneurysms is controversial.

METHODS

We retrospectively identified all traumatic ICA pseudoaneurysms diagnosed on head/neck computed tomographic angiography at a high-volume trauma center over a 10-year period. Radiographic and clinical data were recorded, and a treatment algorithm was derived.

RESULTS

Forty-three pseudoaneurysms were diagnosed in 39 patients. All patients were treated with daily aspirin unless contraindicated, and 82% underwent daily transcranial Doppler ultrasonography with embolic monitoring. A rate of 8 or more emboli per hour was predictive of embolic stroke (P = 0.0076). Acute ischemic or embolic stroke was seen in 7 patients (16%) with an overall mortality in this subpopulation of 42% (n = 3). Four patients (9%) underwent acute surgical treatment (parent vessel sacrifice and/or arterial bypass) for ongoing ischemia. Long-term radiographic and clinical follow-up was obtained for 36 surviving patients (mean = 8 months; range: 1 week-5 years), all of whom were maintained on daily aspirin. No delayed ischemic or embolic events were reported. For ICA pseudoaneurysms treated with aspirin and observation alone, 9 (28%) increased in size, 17 (53%) decreased or stabilized, and 6 (19%) resolved. Enlargement of 5 mm or more in maximal diameter underwent delayed endovascular treatment with a 100% obliteration rate and no complications.

CONCLUSIONS

Traumatic ICA pseudoaneurysms are safely treated with daily aspirin, embolic monitoring, and radiographic surveillance. Acute stroke or hemorrhage, or delayed radiographic progression, are indications for endovascular or surgical treatment.

Prognostic Factors for Neurologic Outcome in Patients with Carotid Artery Stenting

BACKGROUND

Carotid artery stenting (CAS) is a valid treatment for patients with carotid artery stenosis. The long-term outcome and prognostic factors in Asian population after CAS are not clear. This study aimed to identify the prognostic factors among Asian patients who have undergone CAS.

METHODS

We retrospectively analyzed 246 patients with CAS. Annual carotid duplex ultrasound was used to identify restenosis. Peri-procedural complications, restenosis, neurologic outcomes, and mortality were recorded. Cox regression analyses were used to identify prognostic factors.

RESULTS

The mean follow-up time was 49.2 months. Procedural success was achieved in 237 patients (98.3%), and protection devices were used in 208 patients (84.5%). Within 30 days of CAS, 13 (4.3% per procedure) peri-procedural complications occurred. During the follow-up period, 24 (9.7%) patients developed restenosis, and 37 (15.0%) developed ischemic strokes. In a multiple logistic regression analysis, head and neck radiotherapy [hazard ratio (HR) = 9.9, 95% confidence interval (CI), 3.38-29.1, p < .001], stent diameter (HR = 0.72, 95% CI, 0.58-0.89, p = .003), and predilatation (HR = 3.08 95% CI, 1.21-7.81, p = .018) were independent predictors for restenosis. In Cox regression analysis, hypercholesterolemia (HR = 0.25, 95% CI, 0.07-0.94, p = .04), head and neck radiotherapy (HR = 6.2, 95% CI, 1.8-21.3, p = .004), and restenosis (HR = 3.6, 95% CI, 1.1-11.18, p = .04) were predictors for recurrent ipsilateral ischemic stroke.

CONCLUSIONS

CAS provides reliable long-term results in Asian patients with carotid stenosis. Restenosis is associated with an increased rate of recurrent stroke and should be monitored carefully following CAS.

KEY WORDS

Carotid artery disease • Prognosis • Cerebrovascular disease.

Carotid artery stenting: a clinical update

PURPOSE OF REVIEW

Carotid endarterectomy (CEA) has been shown to prevent stroke in patients with severe carotid stenosis. Carotid artery stenting (CAS) has emerged as a less invasive alternative technique. Data regarding comparative effectiveness of CAS and CEA are now available and merit review.

RECENT FINDINGS

Four large randomized controlled trials (RCTs) comparing CAS and CEA have shown a higher rate of stroke in symptomatic patients. The largest and most recent trial reported a lower occurrence of myocardial infarction (MI) following CAS and showed overall comparability of CAS to CEA for both symptomatic and asymptomatic patients. Despite methodological differences, these RCTs are consistent in finding an interaction of patient age with outcomes. In younger patients, CAS appears equivalent or superior to CEA if considering the sum of death, stroke, and MI. In elderly patients, CEA appears to have a lower complication rate. For asymptomatic patients, reduction in event rates with current medical therapy may render previous trial results invalid.

SUMMARY

CAS is an alternative to CEA in patients requiring carotid intervention. Comparison of both CAS and CEA with contemporary medical management will also be required before recommendations can be made regarding the optimal treatment of patients with asymptomatic carotid stenoses.

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.

Comparison of short- and long-term results of drug-eluting vs. bare metal stenting in the porcine internal carotid artery

PURPOSE

To evaluate the development of neointimal hyperplasia after implantation of drug-eluting stents (paclitaxel) compared to bare metal stents in porcine internal carotid arteries (ICAs).

METHODS

While drug-eluting stents have effectively reduced neointimal proliferation in porcine external carotid arteries, the porcine internal carotid artery (ICA) is more sensitive to shear stress and altered flow conditions. Thus, a study was conducted to evaluate bare vs. drug-eluting stents in porcine ICAs. Under general anesthesia, 18 domestic pigs were implanted with paclitaxel-eluting (n = 18) and bare (n = 18) stents in the left and right ICAs, respectively. After 1 and 3 months, control carotid angiography was performed, followed by histopathological and histomorphometric analyses of the stented ICA.

RESULTS

Histopathological results (fibrin deposition, necrosis, inflammation) were similar in the groups at 1 and 3 months. Moreover, the injury score and rate of endothelialization did not differ between the groups. Histomorphometric analysis after 1 month revealed significantly (p<0.05) less neointimal hyperplasia after implantation of paclitaxel-eluting stents. The antiproliferative effect of paclitaxel-eluting stents were maintained during the 3-month follow-up: the neointimal area was 0.7 ± 0.5 vs. 1.2 ± 0.6 mm(2) (p<0.01), the area stenosis was 23.5% ± 13.9% vs. 37.8% ± 14.4% (p<0.01), the maximal neointimal thickness was 0.2 ± 0.1 vs. 0.2 ± 0.9 mm (p<0.05) in paclitaxel-eluting vs. bare stents, respectively. Implantation of paclitaxel-eluting and bare stents did not lead to edge restenosis or vessel remodeling in porcine ICAs at 1 or 3 months.

CONCLUSION

Compared to bare metal stents, drug-eluting stents implanted in the porcine ICA produced significantly less neointimal hyperplasia.

Imaging of the carotid artery

In the study of carotid arteries, modern techniques of imaging allow to analyze various alterations beyond simple luminal narrowing, including the morphology of atherosclerotic plaques, the arterial wall and the surrounding structures. By using CTA and MRI it is possible to obtain three-dimensional rendering of anatomic structures with excellent detail for treatment planning. This paper will detail the role of various imaging methods for the assessment of carotid artery pathology with emphasis on the detection, analysis and characterization of carotid atherosclerosis.

Comparison of carotid artery stenting in patients with single versus bilateral carotid artery disease and factors affecting midterm outcome

BACKGROUND

Carotid artery stenting (CAS) is the method of choice for carotid artery revascularization of patients at high risk for carotid endarterectomy. In this study, we compared the midterm results of CAS in patients with unilateral versus bilateral carotid artery disease.

METHODS AND RESULTS

This is a retrospective analysis of 1-year outcome of 273 consecutive patients in whom 342 CAS procedures were performed. The incidence of periprocedural transient ischemic attacks (TIAs) differed significantly (8% vs. 1%; p = 0.01) among patients with and without bilateral internal carotid disease, and a tendency to a lower occurrence of early adverse events (death, stroke, periprocedural TIA, periprocedural myocardial infarction) was subsequently shown (11% vs. 5%; p = 0.12). At 1-year follow-up, there was a high incidence of adverse events (death, stroke, periprocedural TIA, periprocedural myocardial infarction, restenosis) in patients with bilateral carotid artery disease (40% vs. 14%; p < 0.01), which was mainly driven by a higher incidence of death, periprocedural TIA, and restenosis (p ≤ 0.02 for all). According to multivariate analysis, the independent predictors of midterm adverse events were left ventricular dysfunction, male gender, bilateral carotid artery disease, renal insufficiency, cerebral symptoms within the last 6 months before the intervention, and low-density lipoprotein cholesterol level.

CONCLUSIONS

At midterm follow-up, patients with bilateral carotid artery disease treated by CAS have significantly more adverse events than those with unilateral disease.