Technical challenges in a program of carotid artery stenting

Association of stroke or death with severity of carotid lesion calcification in patients undergoing carotid artery stenting

OBJECTIVE

Carotid artery stenting (CAS) for heavily calcified lesions is controversial due to concern for stent failure and increased perioperative stroke risk. However, the degree to which calcification affects outcomes is poorly understood, particularly in transcarotid artery revascularization (TCAR). With the precipitous increase in TCAR use and its expansion to standard surgical-risk patients, we aimed to determine the impact of lesion calcification on CAS outcomes to ensure its safe and appropriate use.

METHODS

We identified patients in the Vascular Quality Initiative who underwent first-time transfemoral CAS (tfCAS) and TCAR between 2016 and 2021. Patients were stratified into groups based on degree of lesion calcification: no calcification, 1% to 50% calcification, 51% to 99% calcification, and 100% circumferential calcification or intraluminal protrusion. Outcomes included in-hospital and 1-year composite stroke/death, as well as individual stroke, death, and myocardial infarction outcomes. Logistic regression was used to evaluate associations between degree of calcification and these outcomes.

RESULTS

Among 21,860 patients undergoing CAS, 28% patients had no calcification, 34% had 1% to 50% calcification, 35% had 51% to 99% calcification, and 3% had 100% circumferential calcification/protrusion. Patients with 51% to 99% and circumferential calcification/protrusion had higher odds of in-hospital stroke/death (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.02-1.6; P = .034; OR, 1.9; 95% CI, 1.1-2.9; P = .004, respectively) compared with those with no calcification. Circumferential calcification was also associated with increased risk for in-hospital myocardial infarction (OR, 3.5; 95% CI, 1.5-8.0; P = .003). In tfCAS patients, only circumferential calcification/protrusion was associated with higher in-hospital stroke/death odds (OR, 2.0; 95% CI, 1.2-3.4; P = .013), whereas for TCAR patients, 51% to 99% calcification was associated with increased odds of in-hospital stroke/death (OR, 1.5; 95% CI, 1.1-2.2; P = .025). At 1 year, circumferential calcification/protrusion was associated with higher odds of ipsilateral stroke/death (12.4% vs 6.6%; hazard ratio, 1.64; P = .002).

CONCLUSIONS

Among patients undergoing CAS, there is an increased risk of in-hospital stroke/death for lesions with >50% calcification or circumferential/protruding plaques. Increasing severity of carotid lesion calcification is a significant risk factor for stroke/death in patients undergoing CAS, regardless of approach.

Teaching vascular anatomy: the anatomy we know, the anatomy we see or the anatomy we need?

PURPOSE

This article presents the evolution of the subject of vascular anatomy and discusses the associated clinical applicability.

METHODS

Clinically-driven surgical examples met in our everyday practice were used to depict characteristic anatomical paradoxes raised by the inconsistencies between classical anatomical perception, current imaging modalities and modern surgical techniques.

RESULTS

Consequent anatomy-driven modifications of medical devices comprise a characteristic example of the vivid, modern and meaningful role that anatomy can have on clinical decision-making and improvement of technical and clinical success. Clinical experience provides a feedback that shifts the focus of anatomic research towards new fields of interest, such as the role of arterial collateral networks as therapeutic targets. The clinical feedback brings into light queries and issues where traditional anatomical answers may be vague and inadequate to apply, thereby necessitating further research, refinement and reevaluation.

CONCLUSION

While the traditional teaching of vascular anatomy is based on information and illustrations derived from dissection and prosection courses, the development of modern imaging technologies applied in large numbers of living patients and application of minimally invasive techniques challenge our understanding of what should be perceived as fixed and permanent. Moreover, the recently introduced evidence-based philosophy in anatomy elaborate more robust data which not only update, validate and enrich the existing knowledge of anatomical variations but also enable subgroup analyses with respect to race, age and sex, identifying specific anatomic features associated with a significant impact on patient treatment.

Outcomes of Carotid Revascularization versus Optimal Medical Treatment Alone for Asymptomatic Carotid Stenosis: Inverse-Probability-of-Treatment Weighting Using Propensity Scores

BACKGROUND

The benefits and necessity of revascularization for asymptomatic carotid stenosis remains under debate. This study aimed to determine the more durable and beneficial alternative between carotid revascularization and optimal medical treatment (OMT) alone for asymptomatic carotid stenosis.

METHODS

We performed a retrospective analysis of patients with asymptomatic severe carotid stenosis at a tertiary institution between 1994 and 2017. We compared revascularization (carotid endarterectomy [CEA] and carotid artery stenting [CAS]) with OMT alone by using inverse-probability-of-treatment weighting with propensity scores to account for selection bias. The primary end point was a composite of any stroke, myocardial infarction, and death within 30 days, plus ipsilateral stroke thereafter.

RESULTS

A total of 1089 patients were included in the analysis (56% CEA, 25% CAS, 19% OMT alone). Patients who underwent CAS consistently showed greater risk regarding the primary composite end point compared with those who received OMT alone (hazard radio [HR] 3.32, 95% confidence interval 1.014-10.868; P = 0.047), but the CEA group showed no significant difference (HR 1.19, 95% confidence interval 0.385-4.584; P = 0.761). The CAS group had the greatest rates of any stroke within 30 days (4.0%, P = 0.0006) and ipsilateral stroke thereafter (3.68%, P = 0.0009). There was no death within 30 days. In the long-term outcomes, neither CEA nor CAS showed significant differences in HR compared with OMT alone.

CONCLUSIONS

Our study suggests that for stroke prevention in asymptomatic severe carotid stenosis, CAS might be inferior to the other 2 options regarding early outcomes. However, further investigation is required regarding the efficacy and durability of OMT alone.

Aortic arch types and postoperative outcomes after carotid artery stenting in asymptomatic and symptomatic patients

BACKGROUND

The aim of this study was to investigate the influence of the aortic arch type on technical and clinical success of carotid artery stenting (CAS) procedure.

METHODS

Clinical and anatomical data of consecutive patients who underwent CAS from 2010 to 2018 were prospectively collected and retrospectively analyzed. Primary outcome was technical success, define as successful stent delivery and deployment and <30% residual carotid stenosis. Secondary outcomes were death, stroke, myocardial infarction (MI) and transient ischemic attack (TIA) rates at 30 days after CAS. Subgroups analysis with asymptomatic and symptomatic patients were also performed.

RESULTS

During the study period, 523 patients were enrolled and analyzed. Among these, 176 (33.6%) had Type I, 227 (43.4%) had Type II and 120 (23.0%) had Type III or bovine aortic arch (BAA) type. Technical success rate was achieved in 96.0% of cases. At 30 days, if compared with Type I or II, patient with Type III or BAA experienced a higher death rate (0 vs. 0 vs. 1.8%, respectively; P=0.056) and combined postoperative stroke/TIA rate (3% vs. 2.8% vs. 9.9%, respectively; P=0.012). No differences for same outcomes between asymptomatic and symptomatic patients were described, although the latter group experienced more postoperative MI. A multivariate analysis revealed Type III or BAA as an independent risk factor for postoperative stroke/TIA (HR 3.23, IC95% 1.40-7.45; P=0.006).

CONCLUSIONS

In this cohort of patients, death and postoperative neurological complications rates were associated with Type III or BAA, irrespective of symptomatic patients' status. Extremely attention is required during perioperative period in patients who were candidate to CAS and with challenging aortic arch anatomy.

Carotid endarterectomy remains safe in high-risk patients

OBJECTIVE

Carotid endarterectomy (CEA) is a proven intervention for stroke risk reduction in symptomatic and asymptomatic patients. High-risk patients are often offered carotid stenting to minimize the risk and optimize the outcomes. As a referral center for high-risk patients, we evaluated and analyzed our experience with high-risk CEA patients.

METHODS

We retrospectively reviewed consecutive patients who had undergone CEA at a tertiary referral center. The demographics, indications for surgery, physiologic and anatomic risk factors, intraoperative surgical management, perioperative complications, morbidity, and mortality were analyzed. The high-risk physiologic factors identified included an ejection fraction <30%, positive preoperative stress test results, and compromised pulmonary function test results. The high-risk patients included those requiring home oxygen, those with a partial pressure of oxygen of <60 mm Hg, and patients with a forced expiratory volume in 1 second of <30%. The high-risk anatomic factors identified included previous head and/or neck radiation, a history of ipsilateral neck surgery, contralateral nerve palsy, redo CEA, previous ipsilateral stenting, contralateral occlusion, contralateral CEA, nasotracheal intubation, and digastric muscle division. After propensity score matching, patients with and without high-risk physiologic and anatomic factors were compared. The primary outcomes were a composite of stroke, myocardial infarction, and 30-day mortality. The secondary outcomes were cranial injury and surgical site infection.

RESULTS

During a 10-year period, 1347 patients had undergone CEA at the Cleveland Clinic main campus. Of the 1347 patients, 1152 met the criteria for analysis. Propensity score matching found adequate matches for 424 high-risk patients, with 173 patients having at least one physiologic high-risk factor and 293 at least one anatomic high-risk factor. No significant differences were found in the primary composite outcome or any of its components. Overall, the stroke rate for the standard-risk and high-risk patients was 1.9% and 1.4%, respectively. The high-risk patients were significantly more likely to have experienced a cranial nerve injury, although most were temporary. When patients with one or multiple risk factors were analyzed, no significant difference was found in the primary composite outcome or any of its components. Patients with two or more risk factors were significantly more likely to have experienced a cranial nerve injury, with most being temporary.

CONCLUSIONS

In our large series, CEA remained a viable and safe surgical solution for patients with high-risk anatomic and physiologic risk factors, with acceptable stroke, myocardial infarction, and 30-day mortality rates.

Carotid Artery Angioplasty and Stenting for Carotid Stenosis: A Single-Center Experience from Saudi Arabia

Purpose

Atherosclerotic stenosis of the extracranial carotid artery accounts for approximately 20% of all strokes. Both carotid artery endarterectomy and carotid artery angioplasty with stenting (CAAS) are recommended for symptomatic patients with 50% or more stenosis or asymptomatic patients with 70% or more stenosis. CAAS is under-reported in Saudi Arabia, as evidenced by a thorough literature search. In this article, we aim to share our experience of CAAS to call for the necessity of conducting more research on stroke and emphasize the local need of utilizing more endovascular treatments like CAAS.

Materials and Methods

A retrospective single-center observational study was conducted at King Abdulaziz Medical City in Jeddah, Saudi Arabia. The inclusion criteria consisted of all adult patients (18 years and above) with carotid stenosis who were treated with CAAS.

Results

A total of 16 patients were included in the study. The mean age of the participants was 66.9±13.5 years (range 30–87 years). All patients were symptomatic (had a previous stroke or transient ischemic attack). The procedure was successful in 14 patients (87.5%), while it failed in 2 patients (12.5%) due to technical reasons. All patients had no stroke or myocardial infarction within 30 days of the procedure.

Conclusion

Despite the advancement in medicine with free healthcare services in Saudi Arabia, the interventional procedures for secondary prevention of strokes are underutilized. Collaboration between different hospitals will be extremely helpful since few centers in each city are providing such treatments by an expert neurointerventionist and/or strokologist. The good selection of candidates, optimal management of comorbid conditions, and multidisciplinary care may improve outcomes and reduce mortality.

Transcarotid Artery Revascularization Results in Low Rates of Periprocedural Neurologic Events, Myocardial Infarction, and Death

PURPOSE OF REVIEW

Transcarotid artery revascularization (TCAR) is a novel hybrid procedure that reverses carotid flow and places a stent using surgical access of the carotid artery in the neck under local anesthesia. We discuss the indications for carotid revascularization, the clinical rationale for TCAR, and evidence for its potential role in the management of carotid stenosis.

RECENT FINDINGS

Results from pre-clinical studies, prospective single-arm studies, and comparative analyses of registry data indicate that TCAR results in low amounts of periprocedural microembolization, cerebral lesions detectable on magnetic resonance imaging, and neurologic events, myocardial infarctions (MIs), and death. Non-randomized comparisons suggest that TCAR may offer a novel solution to reducing periprocedural stroke, death, and MI in patients with carotid stenosis. A state of equipoise appears to have been reached with TCAR versus the traditional carotid revascularization procedures and a well-controlled randomized trial with careful oversight should be prioritized to obtain level 1 evidence.

Anatomic eligibility for transcarotid artery revascularization and transfemoral carotid artery stenting

OBJECTIVE

Transcarotid artery revascularization (TCAR) has emerged as an alternative to transfemoral carotid artery stenting (tfCAS). We investigated the proportion of carotid arteries undergoing revascularization procedures that would be eligible for TCAR based on anatomic criteria and how many arteries at high anatomic risk for tfCAS would be amenable to TCAR.

METHODS

We performed a retrospective review of consecutive patients who underwent carotid endarterectomy or carotid stenting between 2012 and 2015. Patients were excluded if computed tomography angiography of the neck was not performed within 6 months of the procedure. We assessed TCAR eligibility on the basis of the instructions for use of the ENROUTE Transcarotid Neuroprotection System (Silk Road Medical, Sunnyvale, Calif) and high anatomic risk for tfCAS on the basis of anatomic factors known to make carotid cannulation more difficult or hazardous.

RESULTS

Of the 118 patients and 236 carotid arteries identified, 12 carotid arteries were excluded for presence of an occluded internal carotid artery (ICA). Of the remaining 224 carotid arteries, 72% were eligible for TCAR on the basis of the instructions for use criteria; 100% had 4- to 9-mm ICA diameters, 100% had ≥6-mm common carotid artery (CCA) diameter, 75% had ≥5-cm clavicle to carotid bifurcation distance, and 96% lacked significant CCA puncture site plaque. In addition, 7% of carotid arteries had bifurcation anatomy unfavorable for stenting; thus, of the entire cohort of arteries examined, 68% were eligible for TCAR. Hyperlipidemia (odds ratio [OR], 6.7; 95% confidence interval [CI], 1.7-26; P < .01), chronic obstructive pulmonary disease (OR, 3.5; 95% CI, 1.5-8.3; P < .01), and older age (OR, 1.1; 95% CI, 1.0-1.1; P < .01) were independently associated with TCAR ineligibility, whereas white race (OR, 0.2; 95% CI, 0.0-1.0; P = .048) and beta-blocker use (OR, 0.3; 95% CI, 0.1-0.7; P < .01) were independently associated with TCAR eligibility. In addition, 24% of carotid arteries were considered to be at high risk for tfCAS for the presence of a type III aortic arch (7.6%), severe aortic calcification (3.3%), tandem CCA lesions (7.1%), moderate to severe stenosis at the carotid ostium (8.9%), and tortuous distal ICA precluding embolic filter placement (4.5%). Active smoking (OR, 4.4; 95% CI, 1.9-10; P < .01), hyperlipidemia (OR, 4.0; 95% CI, 1.2-14; P = .03), and older age (OR, 1.1; 95% CI, 1.0-1.1; P = .02) were independently associated with tfCAS ineligibility, whereas preoperative aspirin (OR, 0.1; 95% CI, 0.0-0.4; P < .001) or clopidogrel (OR, 0.3; 95% CI, 0.1-0.8; P = .01) use was associated with tfCAS eligibility. Of the arteries that were considered to be at high risk for tfCAS, 69% were eligible for TCAR.

CONCLUSIONS

The majority of carotid arteries in individuals selected for revascularization meet TCAR eligibility, making TCAR a viable treatment option for many patients.

Crevice sign as an indicator of plaque laceration associated with postoperative severe thromboembolism after carotid artery stenting: a case report

Carotid artery stenting (CAS) is increasingly utilized in patients with carotid artery stenosis. Various intraprocedural and postprocedural complications have been reported in the literature. We present a case of symptomatic major thromboembolism after CAS. The intraprocedural angiogram showed extraordinary slow filling of the contrast medium into the plaque, which we named as "crevice sign." An 83-year-old man presented repeat right amaurosis fugax for 6 months. The radiological examinations revealed 85% stenosis of the origin of the right internal carotid artery. The patient underwent right CAS. The procedure was performed without any problems; however, the angiogram showed slow filling of contrast medium into the carotid plaque through the stent (crevice sign). Sixty minutes later in the ward, the patient presented sudden onset of left hemiparesis and aphasia. Emergency catheter angiography did not show in-stent thrombus, major artery occlusion, or the crevice sign. Magnetic resonance imaging on the next day revealed wide acute infarction of the right cerebral hemisphere. Physicians should be aware of the intraprocedural crevice sign so that a subsequent catastrophic ischemic event can be prevented.

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.

Entrapment of a Cerebral Embolic Protection Device

Cerebral protection devices have significantly reduced the incidence of embolic events in patients undergoing carotid stenting. With the increasing availability of such devices an awareness of the potential complications associated with their deployment is essential. Here we report a patient with entrapment of a filter device within a carotid stent that required surgical removal. The mechanisms underlying this complication and measures to prevent its occurrence are discussed.

Protected Carotid Artery Stenting and Angioplasty via Transfemoral versus Transcervical Approaches

This prospective cohort study was taken to determine whether transcervical carotid artery stenting (CAS) with internal carotid artery (ICA) flow reversal is associated with a lower incidence of embolization and femoral access complication when compared with protected, transfemoral CAS in selected, high-risk patients. From 2002 to October 2004, the authors performed 55 carotid stentings and angioplasties. Among the 24 cases via transfemoral approach, 1 developed transient ischemic attack (TIA), 1 stroke, 1 asystolic cardiac arrest, 2 groin hematoma, 2 technical failure, and 1 restenosis. Among the 31 cases via transcervical approach, 2 patients developed TIAs, 4 bradycardia, 2 cervical hematoma, and 3 technical failures leading to open conversion and carotid endarterectomy. Transcervical CAS with ICA flow reversal eliminates the risk of aortic arch emboli, provides cerebral protection during predeployment manipulation across the carotid lesion, negates preprocedure mapping of the aortic arch configuration, and surpasses difficult aortic arch or transfemoral access.

Cognitive Function After Carotid Artery Revascularization

Clinical investigations designed to contrast the efficacy of carotid endarterectomy (CEA) versus best medical therapy and CEA versus carotid artery stenting (CAS) in patients with carotid artery stenosis have been based on the traditional endpoints of stroke, myocardial infarction, and death. Cognitive function is being increasingly recognized as an important outcome measure that affects patient well-being and functional status. However, it has not been evaluated systematically in the context of carotid revascularization. A decline in cognitive function could occur from microembolic ischemia during surgical dissection (CEA) or intravascular instrumentation (CAS). It could also occur from hypoperfusion during clamping (CEA) or balloon dilation (CAS). Conversely, restoring perfusion could improve cognitive dysfunction that might have occurred from a state of chronic hypoperfusion. It is still unclear whether these complex interactions ultimately result in a net improvement or a deterioration of cognitive function. Furthermore, it is not known whether the 2 methods of carotid revascularization have a differential effect on cognitive outcomes. It is becoming increasingly clear, though, that there is a positive relationship between improvement in cognition and improvement in functional outcome of patients. Vascular surgeons will be well served to remain informed and even actively engaged in the development of this field if they wish to continue providing the high-quality, well-informed care they have traditionally offered to patients with carotid stenosis.

Factors associated with successful revascularization using the aspiration component of ADAPT in the treatment of acute ischemic stroke

Introduction

ADAPT (a direct aspiration first pass technique) has been shown to be fast, cost-effective, and associated with excellent angiographic and clinical outcomes in the treatment of acute ischemic stroke (AIS).

Objective

To identify any and all preoperative factors that are associated with successful revascularization using aspiration alone.

Methods

A retrospective review of 76 patients with AIS treated with thrombectomy was carried out. Cohort 1 included cases in which aspiration alone was successful (Thrombolysis in Cerebral Infarction 2b or 3). Cohort 2 included cases in which aspiration was unsuccessful or could not be performed despite an attempt.

Results

There was no difference between cohorts in gender, race, medications, National Institute of Health Stroke Scale score, IV tissue plasminogen activator, site or side of the occlusion, dense vessel sign, aortic arch type, severe stenosis, clot length, operator years of experience, and guide/aspiration catheters used. Patients in cohort 1 were on average younger (66.5 vs 74.1 years, p=0.025). There was a trend for more patients in cohort 2 to have atrial fibrillation/arrhythmias (62.5% vs 45.5%, p=0.168) and have a cardiogenic stroke etiology (78.1% vs 56.8%, p=0.086). There was also a trend for more reverse curves (2.3 vs 1.7, p=0.107), larger vessel diameter (3.26 mm vs 2.88 mm, p=0.184), larger vessel-to-catheter ratio (2.09 vs 1.87, p=0.192), and worse clot burden score (5.38 vs 6.68, p=0.104) in cohort 2.

Conclusions

Aspiration success was associated with younger age. Our findings suggest that ADAPT can be used for the vast majority of patients but it may be beneficial to use a different method first in the elderly.

Comparison of Flow Impairment during Carotid Artery Stenting Using Two Types of Eccentric Filter Embolic Protection Devices

We investigated the angiographic findings and the clinical outcomes after carotid artery stenting (CAS) using two different, eccentric filter embolic protection devices (EPDs). Between July 2010 and August 2015, 175 CAS procedures were performed using a self-expandable closed-cell stent and a simple eccentric filter EPD (FilterWire EZ in 86 and Spider FX in 89 procedures). The angiographic findings (i.e., flow impairment and vasospasm) at the level of EPDs, neurologic events, and post-operative imaging results were compared between the FilterWire EZ and the Spider FX groups. The CAS was angiographically successful in all 175 procedures. However, the angiographs were obtained immediately after CAS-detected flow impairment in the distal internal carotid artery (ICA) in 11 (6.3%) and ICA spasms at the level of the EPD in 40 cases (22.9%). The incidence of these complications was higher with FilterWire EZ than Spider FX (ICA flow impairment of 10.5% vs. 2.2%, P = 0.03; vasospasm 30.2% vs. 15.7%, P = 0.03). There were nine neurologic events (5.1%); five patients were presented with transient ischemic attacks, three had minor strokes, and one had a major stroke. New MRI lesions were seen in 25 (29.1%) FilterWire-group and in 36 (40.4%) Spider-group patients. The neurologic events and new MRI lesions were not associated with the type of EPD used. Although the ICA flow impairment may result in neurologic events, there was no significant association between the FilterWire EZ and the Spider FX CAS with respect to the incidence of neurologic events by the prompt treatment such as catheter aspiration.

Plaque morphology (the PLAC Scale) on CT angiography: predicting long-term anatomical success of primary carotid stenting

OBJECT

Carotid angioplasty and stenting has emerged as an alternative to carotid endarterectomy for the treatment of atherosclerotic carotid stenosis. Primary carotid stenting, performed using self-expanding stents alone without deliberate use of embolic protection devices and balloon angioplasty, has been shown to be effective and faster, cheaper, and potentially safer than conventional techniques. However, the long-term morphological results of this technique have not been established. The aim of this study was to determine whether preprocedural carotid plaque imaging at the site of maximal stenosis by using CT angiography (CTA) could predict the long-term morphological outcome of primary carotid stenting.

METHODS

One hundred eighty-one patients were treated over an 11-year period. Preprocedural CTA was performed in 102 of these. A morphological scale (the Predicting Long-term outcome with Angioplasty of the Carotid artery [PLAC] Scale), with grades from 0 to 4 and A or B, was used to evaluate the circumferential degree of plaque calcification, and the presence or absence of soft plaque. All patients were followed using duplex carotid ultrasound and plain radiographs. Satisfactory morphological outcome was defined as a peak systolic velocity < 120 cm/s and internal carotid artery/common carotid artery ratio < 1.4.

RESULTS

The average follow-up duration was 29.7 months (median 24.5 months, range 0.3–87 months). Univariate logistic regression demonstrated that a low calcification grade (p < 0.001), less thick calcification (p < 0.001), and moderate amounts of soft plaque (p < 0.001) are factors that are highly associated with good long-term outcome. Multivariate analyses confirmed that these factors are independent of each other in predicting outcome.

CONCLUSIONS

The long-term morphological outcome of primary carotid stenting was predicted with considerable accuracy by using a straightforward CTA carotid plaque grading scale.

Comparison and calibration of a real-time virtual stenting algorithm using Finite Element Analysis and Genetic Algorithms

In this paper, we perform a comparative analysis between two computational methods for virtual stent deployment: a novel fast virtual stenting method, which is based on a spring-mass model, is compared with detailed finite element analysis in a sequence of in silico experiments. Given the results of the initial comparison, we present a way to optimise the fast method by calibrating a set of parameters with the help of a genetic algorithm, which utilises the outcomes of the finite element analysis as a learning reference. As a result of the calibration phase, we were able to substantially reduce the force measure discrepancy between the two methods and validate the fast stenting method by assessing the differences in the final device configurations.

High-Risk Factors in Symptomatic Patients Undergoing Carotid Artery Stenting With Distal Protection

BACKGROUND:

Demographics and vascular anatomy may play an important role in predicting periprocedural complications in symptomatic patients undergoing carotid artery stenting (CAS).

OBJECTIVE:

To predict factors associated with increased risk of complications in symptomatic patients undergoing CAS and to devise a CAS scoring system that predicts such complications in this patient population.

METHODS:

A retrospective study was conducted that included patients who underwent CAS for symptomatic carotid stenosis during a 3-year period. Demographics and anatomic characteristics were subsequently correlated with 30-day outcome measures.

RESULTS:

A total of 221 patients were included in the study. The cumulative rate of periprocedural complications was 7.2%, including stroke (3.2%), myocardial infarction (3.2%), and death (1.4%). Renal disease increased the risk of all complications. National Institutes of Health Stroke Scale score ≥10 at presentation, difficult femoral access, and diseased calcified aortic arch increased the risk of stroke and all complications. Type III aortic arch correlated with increased risk of stroke. Pseudo-occlusion and concentric calcification of the carotid artery increased the risk of myocardial infarction, death, and all complications. Carotid tortuosity and anatomy hostile to the deployment of distal protection devices increased the risk of stroke, myocardial infarction, death, and all complications.

CONCLUSION:

Our results suggest that CAS should be avoided in patients with multiple anatomic risk factors. High presenting National Institutes of Health Stroke Scale score and renal disease also increase the complication risk. The CAS scoring system devised here is simple, reproducible, and clinically valuable in predicting complications risk in symptomatic patients undergoing CAS.

Percutaneous transhepatic portal vein stenting for malignant portal vein stenosis secondary to recurrent perihilar biliary cancer

BACKGROUND

Transhepatic portal vein (PV) stenting has been shown to be one of the most important treatments for patients with PV stenosis caused by hepatopancreatobiliary malignancy.

METHODS

Ten consecutive patients with PV stenosis caused by the recurrence of a perihilar biliary malignancy underwent transhepatic PV stenting. A self-expandable metallic stent was deployed at the stenosis site. The patients were retrospectively analyzed with regard to the procedure, complications, and survival after the stent placement.

RESULTS

The median interval between the primary resection and the PV stenting was 22 months. The initial hepatic resection was a left trisectionectomy with caudate lobectomy in seven patients, a left hepatectomy with caudate lobectomy in one patient, a right anterior sectionectomy with caudate lobectomy following a left hepatectomy in one patient and a partial liver resection in one patient. The angle of the PV around the stenosis was greater in the patients with PV stenosis located in the right posterior PV. Eight patients with successful PV stent placement were able to receive anticancer treatment, with a median survival of 14 months. The remaining two patients without successful PV stent placement survived less than 6 months.

CONCLUSIONS

Portal vein stenting might offer relief from the symptoms associated with PV hypertension and the opportunity for sustainable anticancer therapy in patients with recurrent perihilar biliary malignancy.

Challenging carotid intervention after total arch rerouting and hybrid zone 0 elephant trunk repair for a complicated type A aortic dissection

PURPOSE

To report a challenging carotid intervention after total arch rerouting and hybrid zone 0 elephant trunk repair.

CASE REPORT

A 54-year-old man developed symptomatic left carotid artery restenosis 2 weeks after total arch rerouting and hybrid zone 0 elephant trunk repair for acute retrograde type A aortic dissection with left carotid malperfusion. Because the origins of the 3 supra-aortic branches were already transected and rerouted to the proximal end of the reconstructed ascending aortic graft, the peripheral access routes for carotid intervention were deemed difficult, with little chance of success due to acute angles between these rerouted supra-aortic branches and the ascending aortic graft. Emergent carotid artery stenting was therefore performed via sternal reentry with successful restoration of cerebral perfusion.

CONCLUSION

Total arch rerouting, facilitating hybrid endovascular repair for extensive thoracic aortic disease, creates an extremely deformed arch anatomy that renders subsequent carotid intervention a challenging task.

Balloon-assisted looping technique to perform carotid artery stenting

An acute angle, <90 degrees, at the origin of the internal carotid artery from the common carotid artery poses a significant impediment to carotid artery stenting. We present a "balloon-assisted looping technique" that may facilitate successful crossing of the guidewire over this acute angle and enable successful carotid stenting in protected and unprotected endovascular procedures in patients with these challenging stenoses.

Atherosclerotic plaque vulnerability as an explanation for the increased risk of stroke in elderly undergoing carotid artery stenting

BACKGROUND AND PURPOSE

Recent randomized trials showed an increased periprocedural risk for stroke with increasing age in patients undergoing carotid artery stenting. Manipulation of atherosclerotic plaques during carotid artery stenting can result in plaque rupture with subsequent superimposed thrombus formation, embolization, and cerebrovascular events. We hypothesized that atherosclerotic plaques become more unstable with increasing age and thereby might provide insight into the age-related increased risk of cerebrovascular events during carotid artery stenting.

METHODS

Carotid atherosclerotic plaques were harvested from 1385 consecutive patients undergoing carotid endarterectomy between 2002 and 2010. Carotid plaques were quantitatively analyzed for macrophages, smooth muscle cells, and microvessels; and semiquantitatively analyzed for collagen, calcifications lipid cores, and intraplaque hemorrhages. Patients were divided in 4 groups by age: <60, 60 to 69, 70 to 79, and ≥80 years. Measures of association between age as a continuous variable and histological characteristics were also calculated.

RESULTS

Increasing age was associated with a decrease in the amount of smooth muscle cells in the carotid plaque. More plaques with large atheroma and heavy plaque calcifications were observed among elderly patients. After correction for baseline differences, risk factors, and medication use, age was independently associated with a more vulnerable carotid plaque composition.

CONCLUSIONS

Plaque stability decreases gradually with age. Older patients with carotid stenosis have relatively unstable plaques with low smooth muscle cell content, a high amount of large lipid cores, and more calcified plaques as compared with younger patients. The underlying vulnerable plaque composition in the elderly might be an important contributing factor to the increased risk of stroke for older patients undergoing carotid artery stenting.

Evaluation of robotic endovascular catheters for arch vessel cannulation

OBJECTIVE

Conventional catheter instability and embolization risk limits the adoption of endovascular therapy in patients with challenging arch anatomy. This study investigated whether arch vessel cannulation can be enhanced by a remotely steerable robotic catheter system.

METHODS

Seventeen clinicians with varying endovascular experience cannulated all arch vessels within two computed tomography-reconstructed pulsatile flow phantoms (bovine type I and type III aortic arches), under fluoroscopic guidance, using conventional and robotic techniques. Quantitative (catheterization times, catheter tip movements, vessel wall hits, catheter deflection) and qualitative metrics (Imperial College Complex Endovascular Cannulation Scoring Tool [IC3ST]) performance scores were compared.

RESULTS

Robotic catheterization techniques resulted in a significant reduction in median carotid artery cannulation times and the median number of catheter tip movements for all vessels. Vessel wall contact with the aortic arch wall was reduced to a median of zero with robotic catheters. During stiff guidewire exchanges, robotic catheters maintained stability with zero deflection, independent of the distance the catheter was introduced into the carotid vessels. Overall IC3ST performance scores (interquartile range) were significantly improved using the robotic system: Type I arch score was 26/35 (20-30.8) vs 33/35 (31-34; P = .001), and type III arch score was 20.5/35 (16.5-28.5) vs 26.5/35 (23.5-28.8; P = .001). Low- and medium-volume interventionalists demonstrated an improvement in performance with robotic cannulation techniques. The high-volume intervention group did not show statistically significant improvement, but cannulation times, movements, and vessel wall hits were significantly reduced.

CONCLUSION

Robotic technology has the potential to reduce the time, risk of embolization and catheter dislodgement, radiation exposure, and the manual skill required for carotid and arch vessel cannulation, while improving overall performance scores.

The Coronary Technique for Complex Carotid Artery Stenting in the Setting of Complex Aortic Arch Anatomy

Carotid artery stenting (CAS) remains a viable option for treating carotid artery lesions in high surgical risk patients. We retrospectively reviewed our experience in performing CAS in patients with complex aortic arch anatomy. The ‘‘coronary technique’’ uses an AL1 guiding catheter to engage the origin of the common carotid artery permitting delivery of protection device and stent. In total, 12 patients had complex arch anatomy which precluded access using the standard technique as determined on preoperative imaging. A total of 8 patients with such anatomy underwent femoral artery catheterization with placement of an Amplatz AL1 guide catheter into the common carotid artery. All were able to be successfully treated, with no dissection, neurovascular deficit, or other major complication. Based on this case series, we describe the coronary technique as a safe and viable method for CAS in the setting of complex anatomy which might otherwise preclude CAS.

Refractory In-stent Restenosis Following Carotid Artery Stenting: A Case Report and Review of Operative Management

In-stent restenosis following carotid artery stenting is a challenging problem that vascular surgeons will likely encounter with increasing frequency. The following describes a patient who developed progressive in-stent restenosis 3 years after carotid artery stenting, which was treated with operative therapy after failed balloon angioplasty. A review of the literature describing surgical approaches to the treatment of in-stent restenosis was also performed.

Cutting balloon angioplasty in percutaneous carotid interventions

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Carotid artery stenting for calcified lesions

BACKGROUND AND PURPOSE

Our aim was to assess the feasibility of carotid artery stent placement (CAS) for calcified lesions.

MATERIALS AND METHODS

Using embolic protection devices (EPDs), we performed 51 CAS procedures in 43 patients with severe carotid artery stenosis accompanied by plaque calcification. Before intervention, all lesions were subjected to multidetector-row CT. The arc of the circumferential plaque calcification was measured on axial source images at the site of maximal luminal stenosis, and the total volume of the plaque calcification was determined. The angiographic outcome immediately after CAS, and intra- and postoperative complications were recorded.

RESULTS

The mean arc of calcification was 201.1 +/- 72.3 degrees (range, 76-352 degrees ), and the mean of the total calcification volume was 154.9 +/- 35.4 mm(3) (range, 92-2680 mm(3)). Balloon rupture occurred in 1 procedure (2.0%) at predilation angioplasty; all 51 CAS procedures were successful without clinical adverse effects. Although there was a correlation between the arc of plaque calcification and residual stenosis (r = 0.6, P < .001), excellent dilation with residual stenosis < or =30% was achieved in all lesions. There was no correlation between the total volume of calcification and residual stenosis. None of the patients developed stroke or death within 30 days of the CAS procedure.

CONCLUSION

CAS by using EPDs to treat lesions with plaque calcification is feasible even in patients with near-total circumferential plaque calcification.

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.

Randomized clinical trials: How will results influence clinical practice in the management of symptomatic and asymptomatic extracranial carotid occlusive disease?

Evaluation of the efficacy of carotid endarterectomy and stenting requires careful consideration of clinical trial methodology as applied to the primary clinical end points of the specific trial. Although publication of observational data including registries is helpful in selecting options for further study, these reports are not considered replacements for the randomized clinical trial. This article reviews methodology and results of registries and randomized clinical trials. Pending publication of larger clinical trials on the management of symptomatic and asymptomatic carotid stenosis within the next 1 to 3 years, carotid endarterectomy remains the preferred technique for cerebral revascularization. The only exceptions to this recommendation come from higher risk categories of patients; however, their identification is frequently difficult and controversial.

Carotid Artery Calcification on Multislice Detector-Row Computed Tomography

BACKGROUND

To determine the underlying conditions that affect the degree of calcification of carotid arterial plaques, measured quantitatively using multidetector row computed tomography (MDCT), and to study the association of carotid calcification with clinical symptomatology.

METHODS

We measured the calcification volume of stenotic lesions at the carotid bifurcation using MDCT in 84 consecutive patients who were scheduled to undergo carotid revascularization. These results were compared with the clinical and radiological characteristics of the patients.

RESULTS

On MDCT, calcification in the carotid plaques was present in 78 patients (93%). Compared to the other patients, patients in the highest quartile of calcification volume (quartile 4) had higher serum creatinine levels (p < 0.001) and tended to have fewer symptomatic ischemic events in the territory of the affected carotid artery in the preceding 6 months (29 vs. 49%, p = 0.099); in particular, there were fewer transient symptoms (5 vs. 27%, p = 0.032) and symptoms possibly occurring due to local embolism (14 vs. 37%, p = 0.045). On ultrasound, plaque ulceration was less prevalent in patients in quartile 4 than in the remaining patients (5 vs. 29%, p = 0.026), although the severity of carotid stenosis was similar among all the quartiles.

CONCLUSIONS

Renal dysfunction was associated with enhanced carotid plaque calcification. Patients with severe carotid calcification were found to have a low risk of recent ischemic stroke, presumably due, in part, to a lower prevalence of emboligenic carotid ulceration. MDCT was valuable for the quantitative evaluation of carotid calcification.

Treatment of carotid artery disease: Stenting or surgery?

Carotid endarterectomy (CEA) is the only form of cerebral revascularization for which Level 1 evidence of effectiveness has been reported. Recent studies demonstrate the feasibility of carotid artery stenting (CAS) as an alternative to CEA. Its popularity is due to the perceived advantages of a less invasive treatment for carotid occlusive disease. Two randomized trials have reported no difference in the composite stroke, death, and myocardial infarction rate between CAS and CEA. However, these trials were not powered to identify superiority between the two procedures. A trial sponsored by the National Institutes of Health is currently underway to make that determination. The lead-in phase of this trial noted low complication rates with CAS. These results have encouraged the US Food and Drug Administration to approve the use of CAS in patients with neurologic symptoms (ie, ipsilateral stroke, transient ischemic attacks, and amaurosis fugax) in association with severe medical co-morbidities. Patients with carotid restenosis after previous CEA, anatomically inaccessible lesions above C2, and radiation-induced stenoses may also benefit from preferential treatment with CAS. The National Institutes of Health have now expanded the Carotid Revascularization Endarterectomy Versus Stenting Trial (CREST) to include asymptomatic patients, and resulting data will help to clarify the role of CAS in this subset as well.

Aortic Arch Anomalies are Associated with Increased Risk of Neurological Events in Carotid Stent Procedures

OBJECTIVE

To establish the risk of carotid artery stent (CAS) complications in patients with aortic arch anomalies.

METHODS

In a prospective series of patients submitted to CAS, all cases with arch anomalies were compared with cases with normal arch anatomy (type I, II and III) in order to assess the impact of anatomic characteristics on technical and clinical outcome. Outcome was evaluated in term of neurological complications and technical success.

RESULTS

Of 214 consecutive patients undergoing CAS, 189 (88.3%) had normal arch anatomy and 25 (11.7%) arch anomalies. The arch abnormalities included common origin of brachiocephalic trunk and left common carotid artery in 22 cases (10.2%), separate origin of right subclavian and common carotid in 2 cases (0.9%) and left common carotid agenesis with separate arch origin of internal and external carotid in 1 case (0.5%). The two groups were not different in term of epidemiology and preoperative clinical and morphological characteristics. Technical failure occurred overall in 26 cases (12%) and neurological complication in 14 cases (6.5%). All symptoms were temporary. Technical failure was higher in the arch anomaly group; however the difference did not reach statistical significance (89.6% vs 76.4%, P=0.1). Neurological complications occurred more frequently in the arch anomaly group (20% vs 5.3%, P=0.039). Type of arch was the only variable independently associated with neurological complications (OR=2.01, p=0.026).

CONCLUSION

Aortic arch anomalies are not infrequent and are associated with increased risk of neurological complications. The indication for CAS should be carefully evaluated in these cases.

[Carotid Stenting in France after the EVA 3S and SPACE publications]

Angioplasty of stenoses of the carotid bifurcation is a revascularization procedure that is used successfully in many patients. With more than 10 years of experience now, the feasibility of carotid stenting has been demonstrated. Its distribution is highly variable depending on the country, with a mean penetration rate in Europe of 15% of the number of carotid revascularizations. However, the complication rate is highly variable from one series to another and depends on the type of patient treated and the operator's learning curve. The results of the first two randomized studies comparing endarterectomy and carotid stenting, EVA 3S in France and SPACE in Germany, have just been published. The conclusions of these studies only relate to symptomatic patients, who make up a small proportion of revascularized patients. At 30 days, the French study concluded that surgery was better, and the German study showed no advantage to stenting. The analysis of these results compared to other publications should make it possible to best define the current indications for carotid stenting.

Endovascular treatment of patients with carotid stenosis

Carotid artery stenting is a less invasive technique for carotid revascularization as compared with endarterectomy. However, clinical efficacy for carotid endarterectomy has been established through rigorous randomized clinical trials. Clinical trials and registries on carotid stenting to date have not been powered to compare differential efficacy with endarterectomy in symptomatic patients. Consequently, caution is recommended in use of carotid stenting, pending reports from larger randomized clinical trials.

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.