Revascularization Of Carotid Artery Stenosis Research Articles

A magnetic resonance imaging-based computational analysis of cerebral hemodynamics in patients with carotid artery stenosis.

Management of asymptomatic carotid artery stenosis (CAS) relies on measuring the percentage of stenosis. The aim of this study was to investigate the impact of CAS on cerebral hemodynamics using magnetic resonance imaging (MRI)-informed computational fluid dynamics (CFD) and to provide novel hemodynamic metrics that may improve the understanding of stroke risk. CFD analysis was performed in two patients with similar degrees of asymptomatic high-grade CAS. Three-dimensional anatomical-based computational models of cervical and cerebral blood flow were constructed and calibrated patient-specifically using phase-contrast MRI flow and arterial spin labeling perfusion data. Differences in cerebral hemodynamics were assessed in preoperative and postoperative models. Preoperatively, patient 1 demonstrated large flow and pressure reductions in the stenosed internal carotid artery, while patient 2 demonstrated only minor reductions. Patient 1 exhibited a large amount of flow compensation between hemispheres (80.31%), whereas patient 2 exhibited only a small amount of collateral flow (20.05%). There were significant differences in the mean pressure gradient over the stenosis between patients preoperatively (26.3 vs. 1.8 mmHg). Carotid endarterectomy resulted in only minor hemodynamic changes in patient 2. MRI-informed CFD analysis of two patients with similar clinical classifications of stenosis revealed significant differences in hemodynamics which were not apparent from anatomical assessment alone. Moreover, revascularization of CAS might not always result in hemodynamic improvements. Further studies are needed to investigate the clinical impact of hemodynamic differences and how they pertain to stroke risk and clinical management.

Abstract 12941: In-Hospital Outcomes Among Diabetics Undergoing Transcarotid Artery Revascularization for Carotid Artery Stenosis

Introduction: Transcarotid artery revascularization (TCAR) is a novel procedure to intervene on clinically significant carotid artery stenosis. Periprocedural rates of stroke have remained exceedingly low in clinical trials (<1.5%). Diabetics are known to have elevated risk of periprocedural adverse events with both carotid endarterectomy and carotid artery stenting. TCAR may offer lower periprocedural rates of cerebrovascular accident given its novel flow reversal technique. However, outcomes among diabetics undergoing TCAR remain unknown. We sought to determine periprocedural cardiovascular and cerebrovascular events (MACCE) among diabetics undergoing the TCAR procedure in a large national database. Methods: The Vascular Quality Initiative database was queried for all TCAR procedures performed from January 2012 to March 2021. Baseline demographic information as well as periprocedural outcomes were obtained. In cases in which a patient had multiple procedures, only the most recent procedure was evaluated. Results: A total of 19,341 patients (median age 74 (IQR 67-80), 63.7% male and 90.3% white) underwent the TCAR procedure. Of this n=7,427 (38.4%) were diabetics. Compared to non-diabetics, the diabetic cohort had a higher risk of stroke (1.7% vs 1.3%, p=.02), transient ischemic attack (0.7% vs 0.4% p =.027), and myocardial infarction (0.7% vs 0.5% p=.064). Death remained a rare outcome, with diabetics having 0.5% periprocedural mortality vs 0.4% among non-diabetics (p=.096). Conclusions: TCAR is a safe revascularization method for significant carotid artery stenosis with an elevated risk of periprocedural MACCE in diabetics compared to non-diabetics. Further study is needed to define optimal patient selection for this novel and less-invasive management strategy for carotid artery disease.

Science, Medicine, and the Anesthesiologist

Science, Medicine, and the Anesthesiologist

Association of Adoption of Transcarotid Artery Revascularization With Center-Level Perioperative Outcomes

Transcarotid artery revascularization (TCAR) may serve as a safer alternative to carotid endarterectomy (CEA) for certain patients with carotid artery stenosis. To determine the center-level association of TCAR adoption with overall perioperative outcomes for TCAR and CEA combined at centers performing both procedures. This comparative-effectiveness research was conducted with a difference-in-difference analysis using retrospective data from 2015 to 2019 from the Vascular Quality Initiative registry, a consortium of more than 400 centers in North America. Included patients underwent TCAR or CEA for carotid artery stenosis. Patients who underwent transfemoral carotid stenting were excluded. Data were analyzed from December 2019 through August 2020. Center-level adoption of TCAR vs not. The rate of major adverse cardiovascular events (MACE), a composite of in-hospital stroke, myocardial infarction, or death at 30 days, was measured. Among 86 027 patients who underwent revascularization for carotid artery stenosis, 7664 patients (8.9%) underwent TCAR (mean [SD] age, 73.1 [9.6] years; 2788 [36.4%] women; 6938 White patients [90.6%]; and 3741 patients with symptoms [48.8%]) and 78 363 patients (91.1%) underwent CEA (mean [SD] age, 70.6 [9.2] years; 30 928 [39.5%] women; 70 663 White patients [90.2%]; and 37 883 patients with symptoms [48.3%]). The number of centers performing both TCAR and CEA increased from 15 centers in 2015 to 247 centers in 2019, a more than 16-fold increase. The proportion of all carotid procedures that were TCARs increased from 90 of 12 276 (0.7%) in 2015 to 2718 of 15 956 (17.0%) in 2019, a 24-fold increase. Overall, the crude rate of MACE was similar for TCAR and CEA (178 patients [2.3%] after TCAR vs 1842 patients [2.4%] after CEA; P = .91). However, the rate of MACE over time decreased for CEA (406 of 16 404 patients [2.5%] in 2015 vs 189 of 10 097 patients [1.9%] in 2019; P for trend < .001). The rate of MACE over time decreased for TCAR as well, but the change was not statistically significant (4 of 128 patients [3.1%] in 2016 vs 59 of 2718 patients [2.2%] in 2019; P for trend = .07). Difference-in-difference analysis demonstrated that centers that adopted TCAR had a 10% decrease in the likelihood of MACE at 12 months after TCAR adoption vs if those centers had continued to perform CEA alone (odds ratio, 0.90; 95% CI, 0.81-0.99; P = .04). This comparative-effectiveness study of a cohort of patients who underwent TCAR or CEA found that availability of TCAR at a hospital was associated with a decrease in the likelihood of perioperative MACE after carotid revascularization.

Potential Role of Melatonin as an Adjuvant for Atherosclerotic Carotid Arterial Stenosis.

Carotid artery stenosis (CAS) is an atherosclerotic disease characterized by a narrowing of the artery lumen and a high risk of ischemic stroke. Risk factors of atherosclerosis, including smoking, hypertension, hyperglycemia, hyperlipidemia, aging, and disrupted circadian rhythm, may potentiate atherosclerosis in the carotid artery and further reduce the arterial lumen. Ischemic stroke due to severe CAS and cerebral ischemic/reperfusion (I/R) injury after the revascularization of CAS also adversely affect clinical outcomes. Melatonin is a pluripotent agent with potent anti-inflammatory, anti-oxidative, and neuroprotective properties. Although there is a shortage of direct clinical evidence demonstrating the benefits of melatonin in CAS patients, previous studies have shown that melatonin may be beneficial for patients with CAS in terms of reducing endothelial damage, stabilizing arterial plaque, mitigating the harm from CAS-related ischemic stroke and cerebral I/R injury, and alleviating the adverse effects of the related risk factors. Additional pre-clinical and clinical are required to confirm this speculation.

Dynamics of brain perfusion and cognitive performance in revascularization of carotid artery stenosis.

IntroductionThere is evidence suggesting a detrimental effect of asymptomatic carotid artery stenosis on cognitive function even in the absence of ischemic cerebral lesions. Hypoperfusion has been suggested as pathophysiological mechanism causing cognitive impairment. We aimed to assess cognitive performance and cerebral perfusion changes in patients with carotid artery stenosis without ischemic lesions by arterial spin labeling (ASL) and contrast enhanced (CE) perfusion MRI before and after revascularization therapy.Methods17 asymptomatic patients with unilateral high-grade (≥70%) carotid artery stenosis without evidence of structural brain lesions underwent ASL and CE perfusion MRI and cognitive testing (MMSE, DemTect, Clock-Drawing Test, Trail-Making Test, Stroop Test) before and 6–8 weeks after revascularization therapy by endarterectomy or stenting. Multiparametric perfusion maps (ASL: cerebral blood flow (ASL-CBF), bolus arrival time (ASL-BAT); CE: cerebral blood flow (CE-CBF), mean transit time (CE-MTT), cerebral blood volume (CE-CBV)) were calculated and analyzed by vascular territory. Relative perfusion values were calculated.ResultsMultivariate analysis revealed a significant impact of revascularization therapy on all perfusion measures analyzed. At baseline post-hoc testing showed significant hypoperfusion in MCA borderzones as assessed by ASL-CBF, ASL-BAT, CE-MTT and CE-CBV. All perfusion alterations normalized after revascularization. We did not observe any significant correlation of cognitive test results with perfusion parameters. There was no significant change in cognitive performance after revascularization.ConclusionWe found evidence of traceable perfusion alterations in patients with high grade carotid artery stenosis in the absence of structural brain lesions, which proved fully reversible after revascularization therapy. In this cohort of asymptomatic patients we did not observe an association of hypoperfusion with cognitive performance.

Abstract TP123: Efficacy of Staged Angioplasty to Prevent Cerebral Hyperperfusion Syndrome After Endovascular Revascularization for Carotid Artery Stenosis

Background and aim: Cerebral hyperperfusion syndrome (CHS) including intracranial hemorrhage (ICH) is a serious complication after carotid artery stenting (CAS). Staged angioplasty (SAP), undersized-balloon angioplasty followed by delayed CAS, was reported to be a potential preventable method against CHS. The aim of this study was to clarify the efficacy of SAP to prevent CHS after endovascular carotid revascularization for high-risk patients of CHS. Methods: The STOP CHS study is a multicenter, retrospective study which registered 535 high-risk patients of CHS from 45 Japanese centers, who underwent regular CAS, SAP or angioplasty performed by board-certified neurointerventionists between October 2007 and March 2014. Selection of high-risk patients of CHS was based on imaging tests, such as single-photon emission computed tomography with acetazolamide. We investigated the cumulative periprocedural rates of CHS, ICH and major adverse event (MAE: stroke, myocardial infarction and death) of patients scheduled for regular CAS or SAP (intention-to-treat [ITT] population) and the relationship between SAP and the cumulative incidence of CHS in ITT and as-treated (AT) populations (patients who underwent regular CAS or SAP). Results: A total of 525 patients (532 lesions, 74 women, 72.5±7.5 years old) was included. Angiographic stenosis was 86.2±9.2% and 337 lesions were symptomatic. Scheduled procedures were regular CAS in 419 lesions and SAP in 113 lesions, and final procedures were regular CAS in 428 lesions, SAP in 102 lesions and angioplasty in 2 lesions. The cumulative event rates were CHS in 9.2%, ICH in 4.3% and MAE in 11.5%, and these were higher in patients scheduled for regular CAS than in patients scheduled for SAP(10.5 % vs 4.4%, 5.3% vs 0.9% and 12.9% vs 6.2% with each p-value &lt;0.05, respectively). After multivariate adjustment, schedule for SAP was negatively related to the cumulative incidence of CHS (OR, 0.25; 95%CI, 0.09-0.73). Same applied to implementation of SAP in AT population (OR, 0.28; 95%CI, 0.10-0.82). Conclusion: The cumulative periprocedural event rates of high-risk patients of CHS scheduled for regular CAS or SAP were actually high. SAP was a negative predictor of CHS in both ITT and AT populations.

Changes in cerebral perfusion in patients undergoing revascularization of carotid artery stenosis

Ischemic stroke is caused by atherosclerotic lesions in extra- and intracranial arteries in about 25% of cases. Revascularization surgery has been long and widely used for secondary prevention of ischemic stroke in patients with atherosclerotic lesions of the carotid arteries. However, currently the changes in cerebral perfusion in patients with atherosclerotic lesions of brachiocephalic arteries, who underwent surgical revascularization, are still not fully understood. This article highlights the issues of changes of cerebral hemodynamics in patients undergoing surgery on the carotid arteries.

Stenting versus Endarterectomy and the Impact of Ultra-early Revascularization for Emergent Admissions of Carotid Artery Stenosis

The factors influencing outcomes after emergent admission for symptomatic carotid artery stenosis treated with revascularization by endarterectomy or stenting are yet to be fully elucidated. We analyzed revascularization of carotid artery stenosis for patients admitted emergently using the Nationwide Inpatient Sample (2008-2011). Admission characteristics, economic measures, in-hospital mortality, and iatrogenic stroke were compared between (1) endarterectomy and stenting, (2) patients with and without cerebral infarction, and (3) ultra-early (within 48 hours of admission) and deferred (up to 2 weeks) intervention. 72,797 admissions meeting our inclusion criteria were identified. Factors associated with ultra-early revascularization were male patients, low comorbidity burden, stenosis without infarction, and stenting. Ultra-early intervention significantly decreased cost and length of stay, and stenting for patients without infarction decreased length of stay but increased cost. Patients without infarction treated within 48 hours had significantly lower mortality and iatrogenic stroke rate. Patients with infarction receiving ultra-early revascularization had increased odds of mortality and iatrogenic stroke in comparison with the deferred group. Patients with infarction receiving stenting experienced increased odds of mortality in comparison with those receiving endarterectomy, but there was no significant difference in iatrogenic stroke rate. Recombinant tissue plasminogen activator (rtPA) administration on the day of revascularization greatly increased the odds of iatrogenic stroke and mortality. Larger prospectively randomized trials evaluating the optimum timing of revascularization after emergent admission of carotid artery stenosis seem warranted.

Abstract W P104: Comparison of Carotid Endarterectomy and Stenting for Carotid Artery Stenosis with Coronary Artery Disease

Objective: Coronary artery disease (CAD) is a major comorbidity usually developing in patients with carotid artery stenosis and increases the risk of revascularization in these patients. We retrospectively evaluated the impact of CAD on the outcomes of carotid endarterectomy (CEA) and carotid artery stenting (CAS) at a single center. Methods: We reviewed data of 643 lesions (451 CEA and 192 CAS) in 599 patients who underwent carotid revascularization at our institute between 1998 and 2011. We defined a history of myocardial infarction (MI), coronary artery bypass surgery, or percutaneous coronary intervention as previous CAD and &gt;75% stenosis in more than 2 coronary artery areas as multivessel CAD. Periprocedural stroke, MI, or death from any cause and ipsilateral stroke, MI, or death within a year after treatment were recorded. Results: Of the 643 lesions, 123 (19.1%) were categorized as “previous CAD” and 73 (11.4%) as “multivessel CAD.” The number of cases of multivessel CAD was significantly higher in the CAS group than the CEA group (14.5% vs. 9.9%, p = 0.009). Of the 102 cases indicated for coronary intervention at a preoperative period, 85 were treated for CAD before carotid revascularization. No periprocedural MI was observed in both the groups, and only 1 case showed MI within a year after CEA (0.2%). The CEA group showed no significant relationship between previous or multivessel CAD and any periprocedural or 1-year postoperative event. In the CAS group, multivessel CAD was identified as an independent risk factor for periprocedural stroke (odds ratio [OR]: 11.23; 95% confidence interval [CI]: 2.96-48.91; p = 0.0004) and ipsilateral stroke and death within a year of treatment (OR: 6.76; 95% CI: 2.09-22.38; p = 0.001). Conclusion: Previous or multivessel CAD did not increase the risk of MI or death within 1 year after revascularization of carotid artery stenosis, but multivessel CAD was an independent risk factor for stroke after CAS. Thus, the option of CAS should be carefully considered in cases of carotid artery stenosis with multivessel CAD.

Management of Asymptomatic Internal Carotid Artery Stenosis

Optimal management of patients with asymptomatic carotid artery stenosis remains unclear. Although 2 high-quality randomized clinical trials demonstrated reductions in ispsilateral stroke rates in patients without symptoms after carotid endarterectomy, medical therapy of asymptomatic carotid artery stenosis has reduced rates of stroke to approximately 1% per year, raising questions about the generalizability of these previous trials to current medical practice. However, reductions in adverse events after revascularization can make revascularization more attractive. The emergence of percutaneous revascularization for carotid artery stenosis has raised further questions about optimal management of asymptomatic carotid artery stenosis. This Grand Rounds summarizes the factors to consider when counseling patients and making clinical decisions regarding medical therapy and revascularization for patients with asymptomatic carotid artery stenosis. This information should provide clinicians with the knowledge base to counsel patients about the risks and benefits of treatment options.

Post-carotid stent ultrasound provides critical data to avoid rare but serious complications

Carotid stenting is a common procedure for revascularization of carotid artery stenosis. In this study, we evaluated the role of carotid ultrasound post carotid stenting. In a retrospective analysis, we identified 45 patients who received post-stent ultrasound. On routine follow-up we measured a range for peak systolic velocity of 33–150 cm/s and end diastolic velocity 11–52 cm/s. We also identified two cases, where immediate post-stent ultrasound provided critical data that required further intervention, and potentially avoided serious complications.

Revascularization of carotid artery stenosis - a brief update on current evidence

Major and long-awaited trials comparing carotid endarterectomy (CEA) with carotid stenting (CAS) were published in recent years. Both, ICSS and CREST, documented a higher rate of periprocedural stroke and death in CAS, in particular in elderly patients, thereby confirming the results of prior trials and meta-analyses. In CREST, the composite endpoint included myocardial infarction (MI), which led to statistical equipoise between the treatment arms due to a higher rate of MI with CEA. However, whether MI is a relevant endpoint in trials for stroke prevention remains debatable. The stroke preventive benefit seems equally sustained after CEA and CAS, although the significance of restenoses, whose frequency is twice as high after CAS compared to CEA, is unclear in the long range. Emergent CEA in patients with clinically unstable carotid stenosis is associated with a very high complication risk, but the optimal treatment strategy for these patients remains to be elucidated. Recent evidence indicates a very low stroke risk of asymptomatic stenoses with intensive medical treatment, rendering revascularization almost unnecessary. The detection of microembolic signals on transcranial Doppler and rapid stenosis progression by duplex sonography might help to identify patients with higher stroke risk in whom revascularization is warranted.

Carotid endarterectomy was performed with lower stroke and death rates than carotid artery stenting in the United States in 2003 and 2004

Although carotid endarterectomy (CEA) is the gold standard for the treatment of carotid artery stenosis, the recent United States Food and Drug Administration approval of carotid artery stenting (CAS) may have led to its widespread use outside of clinical trials and registries. This study compared in-hospital postoperative stroke and mortality rates after CAS and CEA at the national level. The Nationwide Inpatient Sample (NIS) was queried to identify all patient-discharges that occurred for revascularization of carotid artery stenosis. The International Classification of Diseases, 9th Revision, Clinical Modification procedure codes for CEA (38.12), CAS (00.63), and insertion of noncoronary stents (39.50, 39.90) were used in conjunction with the diagnostic codes for carotid artery stenosis, with (433.11) and without (433.10) stroke. Primary outcome measures included in-hospital postoperative stroke and death rates. Multivariate logistic regressions were performed to evaluate independent predictors of postoperative stroke and mortality. Adjustment was made for age, sex, medical comorbidities, admission diagnosis, procedure type, year, and hospital type. During the calendar years 2003 and 2004, an estimated 259,080 carotid revascularization procedures were performed in the United States. CAS had a higher rate of in-hospital postoperative stroke (2.1% vs 0.88%, P < .0001) and higher postoperative mortality (1.3% vs 0.39%) than CEA. For asymptomatic patients (92%), the postoperative stroke rate was significantly higher for CAS than CEA (1.8% vs 0.86%, P < .0001), but the mortality rate was similar (0.44% vs 0.36%, P = .36). For symptomatic patients (8%), the rates for postoperative stroke (4.2% vs 1.1%, P < .0001) and mortality (7.5% vs 1.0%, P < .0001) were significantly higher after CAS. By multivariate regression, CAS was independently predictive of postoperative stroke (odds ratio [OR], 2.49; 95% confidence interval [CI], 1.91 to 3.25). CAS was also associated with in-hospital postoperative mortality for asymptomatic (OR, 2.37; 95% CI, 1.46 to 3.84) and symptomatic (OR, 2.64; 95% CI, 1.89 to 3.69) patients. As determined from a large representative national sample including the years 2003 and 2004, the in-hospital stroke rate after CAS for asymptomatic patients was twofold higher than after CEA. For symptomatic patients, the respective in-hospital stroke and mortality rates were fourfold and sevenfold higher. These unexpected results indicate that further randomized controlled trials with homogenous symptomatic and asymptomatic patient groups should be performed.

Long-Term Histopathologic and IVUS Evaluations of a Novel Coiled Sheet Stent in Porcine Carotid Arteries

Carotid angioplasty with stent placement has been proposed as an alternative method for revascularization of carotid artery stenosis. A novel stent with a laser-cut, rolled sheet of Nitinol (EndoTex Interventional Systems, Inc., Cupertino, CA) has been developed to customize treatment of stenotic lesions in carotid arteries utilizing a single stent, designed to adapt to multiple diameters and to tapered or nontapered configurations. The purpose of this study is to evaluate the conformability and vascular response to a novel stent in a chronic porcine carotid model using serial three-dimensional intravascular ultrasound (IVUS) analysis as well as histological examination. Ten Yucatan pigs underwent stent implantation in both normal carotid arteries with adjunctive balloon angioplasty. Three-dimensional IVUS analysis was performed before stent implantation, after adjunctive balloon angioplasty, and at follow-up [1 month (n = 6), 3 months (n = 6), or 6 months (n = 8)]. Histological examination (injury score, percent plaque obstruction, and qualitative analysis) was also performed. All stents were successfully deployed and well apposed in different sized vessels (lumen area range: 19-30 mm(2)). Volumetric IVUS analysis showed no significant difference between the lumen areas before stent implantation and after adjunctive balloon angioplasty and no stent area change at each follow-up point compared to immediately postprocedure. Histological examination revealed minimal injury and neointimal hyperplasia at each follow-up point. In the chronic porcine carotid model, the novel stent system demonstrated good conformability, resulting in minimal vessel injury and neointimal formation.

Silent Cerebral Ischemia Detected With Diffusion-Weighted Imaging in Patients Treated With Protected and Unprotected Carotid Artery Stenting

Percutaneous transluminal angioplasty with stent (CAS) is an alternative method to endarterectomy in the revascularization of carotid artery stenosis. Protected CAS is currently used to prevent distal embolization. Diffusion-weighted MRI (DWI) is the most sensitive tool to evaluate silent cerebral ischemia. The purpose of this research was to assess the incidence of cerebral embolic lesions during CAS and to evaluate whether cerebral protection devices can reduce the number of silent cerebral ischemia with respect to unprotected CAS. Fifty-two patients with high-grade internal stenosis underwent CAS; 30 patients (group a) were treated with a cerebral protection device, and 22 (group b) were treated without it. All of the patients were evaluated preoperatively and postoperatively with fluid-attenuated inversion recovery and DWI sequences to depict the number of new embolic silent cerebral lesions. Embolic silent cerebral lesions occurred in 30% of CAS. Cerebral protection devices reduce the number of new lesions significantly reducing the consistent lesions ipsilateral to the treated vessel. Inconsistent lesions do not differ in both groups of patients. Clinical, radiological, and procedural variables do not correlate with the appearance of new cerebral lesions. Embolic cerebral lesions detected with DWI are more frequent with unprotected CAS, although they are present also with the use of cerebral protection devices. Probably a part of silent cerebral lesions arise from the procedural maneuver in the aortic arch.