Acute thromboses and occlusions of dual layer carotid stents in endovascular treatment of tandem occlusions

Development of a Novel Statistical Model for Predicting Clinical Outcomes in Stroke Patients With Tandem Occlusions After Endovascular Therapy

BACKGROUND

Tandem occlusions are intracranial large vessel occlusions (LVOs) with a concomitant ipsilateral extracranial internal carotid artery occlusion and can cause more severe stroke symptoms.

AIM

To develop a simple, rigorously cross-validated novel tool to predict clinical outcomes following tandem occlusion in patients with acute LVO stroke, based on data that are easily available to clinicians. To have used machine learning approaches to utilize the available information from clinical and angiographic data to make predictive models able to distinguish between mortality versus survival and good (modified Rankin Scale (mRS) ≤ 2) versus unfavorable neurological outcomes (mRs ≥ 3) Materials and methods: Retrospective data from 87 consecutive patients with anterior circulation stroke and tandem occlusions who underwent mechanical thrombectomy and stenting between December 2009 and January 2020 were analyzed. Patients were stratified into three groups based on the location of their LVO, and these groups were compared using statistical tests. Predictive models were built and cross-validated 1000 times to estimate their predictive power, measured by accuracy and area under the receiver operating curve (AUROC).

RESULTS

For distinguishing good outcome (mRS ≤ 2) versus poor outcome (mRS ≥ 3), the model comprised age, initial National Institute of Health Stroke Scale (NIHSS) score, Alberta Stroke Program Early CT Score (ASPECTS), NIHSS at 24 hours, NIHSS at discharge and intracranial haemorrhage and yielded an accuracy of 83% and the AUROC of 0.91. For mortality prediction, the model comprised age, initial NIHSS, intravenous thrombolysis, NIHSS at 24 hours and NIHSS at discharge and yielded an accuracy of 91% and an AUROC of 0.94.

CONCLUSIONS

Models developed exhibit strong predictive performance and can distinguish between both the instances of survival versus mortality and good versus poor outcome with an aim to support clinicians in deciding on optimal management for these complex patients. The developed model will help identify those at risk of poorer outcomes and the prospective better selection of patients with acute ischaemic large vessel stroke secondary to tandem occlusions.

A macrofluidic model to investigate the intrinsic thrombogenicity of clinically used stents and develop less thrombogenic stents

Microfluidic blood flow models have been instrumental to study the functions of blood platelets in hemostasis and arterial thrombosis. However, they are not suited to investigate the interactions of platelets with the foreign surfaces of medical devices such as stents, mainly because of the dimensions and geometry of the microfluidic channels. Indeed, the channels of microfluidic chips are usually rectangular and rarely exceed 50 to 100 μm in height, impairing the insertion of clinically used stents. To fill this gap, we have developed an original macrofluidic flow system, which precisely reproduces the size and geometry of human vessels and therefore represents a biomimetic perfectly suited to insert a clinical stent and study its interplay with blood cells. The system is a circular closed loop incorporating a macrofluidic flow chamber made of silicone elastomer, which can mimic the exact dimensions of any human vessel, including the coronary, carotid or femoral artery. These flow chambers allow the perfect insertion of stents as they are implanted in patients. Perfusion of whole blood anticoagulated with hirudin through the device at relevant flow rates allows one to observe the specific accumulation of fluorescently labeled platelets on the stent surface using video-microscopy. Scanning electron microscopy revealed the formation of very large thrombi composed of tightly packed activated platelets on the stents.

Pretreatment with a dual antiplatelet and anticoagulant (APAC) reduces ischemia-reperfusion injury in a mouse model of temporary middle cerebral artery occlusion-implications for neurovascular procedures

BACKGROUND

Several neurovascular procedures require temporary occlusion of cerebral arteries, leading to ischemia of unpredictable length, occasionally causing brain infarction. Experimental models of cerebral ischemia-reperfusion injury have established that platelet adhesion and coagulation play detrimental roles in reperfusion injury following transient cerebral ischemia. Therefore, in a model of cerebral ischemia-reperfusion injury (IRI), we investigated the therapeutic potential of a dual antiplatelet and anticoagulant (APAC) heparin proteoglycan mimetic which is able to bind to vascular injury sites.

METHODS

Brain ischemia was induced in mice by transient occlusion of the right middle cerebral artery for 60 min. APAC, unfractionated heparin (UFH) (both at heparin equivalent doses of 0.5 mg/kg), or vehicle was intravenously administered 10 min before or 60 min after the start of ischemia. At 24 h later, mice were scored for their neurological and motor behavior, and brain damage was quantified.

RESULTS

Both APAC and UFH administered before the onset of ischemia reduced brain injury. APAC and UFH pretreated mice had better neurological and motor functions (p < 0.05 and p < 0.01, respectively) and had significantly reduced cerebral infarct sizes (p < 0.01 and p < 0.001, respectively) at 24 h after transient occlusion compared with vehicle-treated mice. Importantly, no macroscopic bleeding complications were observed in either APAC- or UFH-treated animals. However, when APAC or UFH was administered 60 min after the start of ischemia, the therapeutic effect was lost, but without hemorrhaging either.

CONCLUSIONS

Pretreatment with APAC or UFH was safe and effective in reducing brain injury in a model of cerebral ischemia induced by transient middle cerebral artery occlusion. Further studies on the use of APAC to limit ischemic injury during temporary occlusion in neurovascular procedures are indicated.

Safety and Efficacy of Carotid Artery Stenting with the CGuard Double-layer Stent in Acute Ischemic Stroke

BACKGROUND

Double-layer stents show promising results in preventing periinterventional and postinterventional embolic events in elective settings of carotid artery stenting (CAS). We report a single-center experience with the CGuard stent in the treatment of acute ischemic stroke (AIS) due to symptomatic internal carotid artery (ICA) stenosis or occlusion with or without intracranial occlusion.

METHODS

We retrospectively analyzed all patients who received a CGuard stent in the setting of AIS at our institution. Neuroimaging and clinical data were analyzed with the following primary endpoints: technical feasibility, acute and delayed stent occlusion or thrombosis, distal embolism, symptomatic intracranial hemorrhage (sICH) and functional outcome at 3 months.

RESULTS

In 33 patients, stenting with the CGuard was performed. Stent deployment was successful in all patients (28 with tandem occlusions, 5 with isolated ICA occlusion). Transient acute in-stent thrombus formation occurred in three patients (9%) without early stent occlusion. Delayed, asymptomatic stent occlusion was seen in 1 patient (3%) after 49 days. Asymptomatic periinterventional distal emboli occurred in 2 patients (6%), 1 patient experienced a transient ischemic attack 79 days after the procedure and 1 patient (3%) developed sICH. Favorable clinical outcome (mRS 0-2) at 3 months was achieved in 12 patients (36%) and the mortality rate was 24%.

CONCLUSION

The CGuard use in emergencies was technically feasible, the safety has to be confirmed by further multicentric studies.

PERFORMANCE 1 study: Novel carotid stent system with integrated post-dilation balloon and embolic protection device

OBJECTIVES

The PERFORMANCE I study was designed to evaluate the safety and feasibility of the Neuroguard IEP® System, a novel carotid stent system with an integrated embolic filter and post-dilatation balloon, to treat clinically significant carotid artery stenosis.

BACKGROUND

The risk of major adverse events during carotid artery stenting is comparable to carotid endarterectomy, however, the risk of minor stroke remains higher with stenting.

METHODS

In total, 67 patients undergoing carotid artery stenting were enrolled at nine centers in Europe. Follow-up assessments included neurological exams, duplex ultrasound, 12-lead electrocardiogram, and cardiac enzyme analysis. The primary endpoint was the 30-day composite rate of stroke, death, and myocardial infarctions versus a prespecified performance goal. Secondary endpoints included procedure success, device success, and target lesion revascularization.

RESULTS

The study population was predominantly male (74.6%) with a mean age of 69.3 ± 8.9 years and 67% of subjects met at least one criterion placing them at an elevated risk for adverse events following carotid endarterectomy. All patients were treated successfully with the study device. There were no deaths or strokes within 30 days of the index procedure. One subject (1.5%) experienced a non-ST elevation myocardial infarction at day 17. The primary endpoint was met with a 30-day major adverse events rate of 1.5% (1/67). Through 12-month follow-up, there were no strokes, neurological deaths, target lesion revascularizations, or instances of in-stent-restenosis.

CONCLUSIONS

Results from this study demonstrate the Neuroguard IEP system is safe and feasible with a stroke/death rate of 0% at 30 days. A large pivotal study is currently underway.

Comparison of Restenosis Risk in Single-Layer versus Dual-Layer Carotid Stents: A Duplex Ultrasound Evaluation

PURPOSE

The aim of this study was to report intermediate-term results of duplex ultrasound follow-up of carotid artery stenting performed with the dual-layer stent as compared to concurrent patients treated with other commercially available single-layer carotid stents.

MATERIALS AND METHODS

A single centre, retrospective, nonrandomized study including 162 non-consecutive patients with 199 implanted carotid stents treated over a 7-year period was conducted. Patients with at least one ultrasound examination after treatment were included. Procedural and follow-up data for patients treated with the dual-layer stent implantation (83 stents) vs first-generation carotid stents implantations (116 stents) were compared.

RESULTS

The median follow-up time was 24.0 months (IQR 10-32 months) for dual-layer stents and 27.5 months (IQR 10.3-59 months) for single-layer stents. The rate of severe restenosis was significantly higher in the dual-layer stent group than in the single-layer group (13.3% [11/83] vs 3.4% [4/116], p = 0.01). Seven reinterventions were performed in 5 patients with dual-layer stents. The rate of reintervention was significantly higher compared to no reinterventions in single-layer stents (6% [5/83] vs 0% [0/116], p = 0.012). Patients with restenosis had significantly higher presence of dyslipidaemia (100% [12/12] vs 63.3% [95/150], p = 0.009).

CONCLUSIONS

In this real-world cohort of patients undergoing carotid artery stenting, the patients treated with low-profile dual-layer micromesh stent showed higher rates of restenosis and reinterventions compared to first-generation single-layer stents.

Cervical carotid occlusion in acute ischemic stroke: Should we give tPA?

Background:

Acute ischemic stroke (AIS) due to cervical internal carotid artery (cICA) occlusion is challenging to treat, with the lower revascularization rates, higher risk for complications, and poor response to thrombolytic therapy compared to isolated intracranial occlusions. While emergent revascularization through mechanical thrombectomy (MT) improves outcomes, the impact of tissue plasminogen activator (tPA) on outcomes in this subgroup of patients remains unclear. The objective of this study is to report our preliminary experience in treating AIS with cICA occlusions secondary to severe atherosclerotic stenosis and to establish the need for further clinical studies to determine the optimal intervention strategy for these lesions.

Methods:

Data were collected on patients who presented with acute cICA occlusion who underwent MT and either acute or staged carotid angioplasty and stenting. We compare patients who received tPA to those who did not, analyzing revascularization times, outcomes, and complications between the two populations, and discuss how this influenced our preferred treatment approach.

Results:

Twenty-one patients met inclusion criteria, seven of who received tPA and 14 did not receive tPA before surgical intervention. Procedural and functional outcomes were similar between the two populations. TPA administration correlated with a higher rate of vessel reocclusion in staged procedures and trended toward higher rates of symptomatic ICH and 90-day mortality.

Conclusion:

Emergent revascularization with acute cICA stenting carries advantages, but its safety is precluded by tPA administration. We suggest a trial which randomizes patients with cICA occlusions to receiving either tPA or dual antiplatelet therapy before surgical intervention, aiming to ultimately improved outcomes in these patients.

Endovascular treatment of ischemic stroke due to isolated internal carotid artery occlusion: ETIS registry data analysis

BACKGROUND

The best treatment for acute ischemic stroke (AIS) due to isolated cervical internal carotid artery occlusion (CICAO) (i.e., without associated occlusion of the circle of Willis) is still unknown. In this study, we aimed to describe EVT safety and clinical outcome in patients with CICAO.

METHODS

We analyzed data of all consecutive patients, included in the Endovascular Treatment in Ischemic Stroke (ETIS) Registry between 2013 and 2020, who presented AIS and proven CICAO on angiogram and underwent EVT. We assessed carotid recanalization, procedural complications, National Institutes of Health Stroke Scale (NIHSS) at 24 h post-EVT, and 3-month favorable outcome (modified Rankin Scale, mRS ≤ 2 or equal to the pre-stroke value).

RESULTS

Forty-five patients were included (median age: 70 years; range: 62-82 years). The median NIHSS before EVT was 14 (9-21). Carotid stenting was performed in 23 (51%) patients. Carotid recanalization at procedure end and on control imaging was observed in 37 (82%) and 29 (70%) patients, respectively. At day 1 post-EVT, the NIHSS remained stable or decreased in 25 (60%) patients; 12 (29%) patients had early neurologic deterioration (NIHSS ≥ 4 points). The rate of procedural complications was 36%, including stent thrombosis (n = 7), intracranial embolism (n = 7), and symptomatic intracranial hemorrhage (n = 1). At 3 months, 18 (40%) patients had a favorable outcome, and 10 (22%) were dead.

CONCLUSION

Our study suggests that EVT in AIS patients with moderate/severe initial deficit due to CICAO led to high rate of recanalization at day 1, and a 40% rate of favorable outcome at 3 months. There was a high rate of procedural complication which is of concern. Randomized controlled trials assessing the superiority of EVT in patients with CICAO and severe deficits are needed.

Acute Carotid Artery Stenting Versus Balloon Angioplasty for Tandem Occlusions: A Systematic Review and Meta-Analysis

Background Despite thrombectomy having become the standard of care for large-vessel occlusion strokes, acute endovascular management in tandem occlusions, especially of the cervical internal carotid artery lesion, remains uncertain. We aimed to compare efficacy and safety of acute carotid artery stenting to balloon angioplasty alone on treating the cervical lesion in tandem occlusions. Similarly, we aimed to explore those outcomes' associations with technique approaches and use of thrombolysis. Methods and Results We performed a systematic review and meta-analysis to compare functional outcomes (modified Rankin Scale), reperfusion, and symptomatic intracranial hemorrhage and 3-month mortality. We explored the association of first approach (anterograde/retrograde) and use of thrombolysis with those outcomes as well. Two independent reviewers performed the screening, data extraction, and quality assessment. A random-effects model was used for analysis. Thirty-four studies were included in our systematic review and 9 in the meta-analysis. Acute carotid artery stenting was associated with higher odds of modified Rankin Scale score ≤2 (odds ratio [OR], 1.95 [95% CI, 1.24-3.05]) and successful reperfusion (OR, 1.89 [95% CI, 1.26-2.83]), with no differences in mortality or symptomatic intracranial hemorrhage rates. Moreover, a retrograde approach was significantly associated with modified Rankin Scale score ≤2 (OR, 1.72 [95% CI, 1.05-2.83]), and no differences were found on thrombolysis status. Conclusions Carotid artery stenting and a retrograde approach had higher odds of successful reperfusion and good functional outcomes at 3 months than balloon angioplasty and an anterograde approach, respectively, in patients with tandem occlusions. A randomized controlled trial comparing these techniques with structured antithrombotic regimens and safety outcomes will offer definitive guidance in the optimal management of this complex disease.

Effectiveness and safety of dual-layer stents in carotid artery disease: a systematic review

INTRODUCTION

Carotid artery stenting (CAS) has emerged as a minimally invasive alternative to carotid endarterectomy (CEA) in atherosclerotic carotid artery disease, even though the risk for procedural stroke after CAS remains significantly higher. Recently, in order to reduce embolic cerebral events after CAS, a new generation of dual-layer stents (DLS) has been developed. This review aimed to perform a detailed analysis of the available evidence on safety and efficacy of DLS in both symptomatic and asymptomatic atherosclerotic carotid artery stenosis.

EVIDENCE ACQUISITION

A systematic review was conducted according to the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. The primary endpoint was the 30-day rate of myocardial infarction (MI), stroke and death. Secondary outcomes included rate and timing of stent occlusion/restenosis.

EVIDENCE SYNTHESIS

A total of 20 articles with 1193 patients were included. Thirty-day MI ranged from 0-5%, 30-day stroke ranged from 0-10.5% and 30-day mortality ranged from 0-10%. Stent occlusion rate ranged from 0-52.4%, the majority of which occurred intraprocedurally (N.=50; 61.7%), in emergency treated patients. The incidence of new ipsilateral cerebral ischemic lesions after CAS with DLS was reported in five studies, ranging from 5.5-37%.

CONCLUSIONS

Despite the theoretic advantage of reducing the risk for procedural embolic events when compared to conventional stents, high quality evidence is scarce. Also, safety issues regarding DLS in the emergency setting have been raised, particularly for thrombotic complications. Additional data from well-designed Randomized Controlled Trials are needed to assert the true value of DLS.

Proximal Internal Carotid artery Acute Stroke Secondary to tandem Occlusions (PICASSO) international survey

BACKGROUND

While mechanical thrombectomy (MT) is the standard of care for large vessel occlusion strokes, the optimal management of tandem occlusions (TO) remains uncertain. We aimed to determine the current practice patterns among stroke physicians involved in the treatment of TO during MT.

METHODS

We distributed an online survey to neurovascular practitioners (stroke neurologists, neurointerventionalists, neurosurgeons, and radiologists), members of professional societies. After 2 months the site was closed and data were extracted and analyzed. We divided respondents into acute stenting and delayed treatment groups and responses were compared between the two groups.

RESULTS

We received 220 responses from North America (48%), Latin America (28%), Asia (15%), Europe (5%), and Africa (4%). Preferred timing for cervical revascularization varied among respondents; 51% preferred treatment in a subsequent procedure during the same hospitalization whereas 39% preferred to treat during MT. Angioplasty and stenting (41%) was the preferred technique, followed by balloon angioplasty and local aspiration (38%). The risk of intracerebral hemorrhage was the most compelling reason for not stenting acutely (68%). There were no significant differences among practice characteristics and timing groups. Most practitioners (70%) agreed that there is equipoise regarding the optimal endovascular treatment of cervical lesions in TO; hence, 77% would participate in a randomized controlled trial.

CONCLUSIONS

The PICASSO survey demonstrates multiple areas of uncertainty regarding the medical and endovascular management of TOs. Experts acknowledged the need for further evidence and their willingness to participate in a randomized controlled trial to evaluate the best treatment for the cervical TO lesion.

Tandem Carotid Lesions in Acute Ischemic Stroke: Mechanisms, Therapeutic Challenges, and Future Directions

Approximately 15% of patients undergoing endovascular thrombectomy for anterior circulation acute ischemic stroke have a tandem lesion, defined as a severe stenosis or occlusion of the cervical internal carotid artery ipsilateral to its intracranial occlusion. Patients with tandem lesions have worse outcomes than patients with isolated intracranial occlusions, but the optimal management of their carotid lesions during endovascular thrombectomy remains controversial. The main options commonly used in current practice include acute stent placement in the carotid lesion versus thrombectomy alone without definitive revascularization of the carotid artery. While treatment decisions for these patients are often complex and strategies vary according to clinical, anatomic, and technical considerations, only results from randomized trials comparing these approaches are likely to strengthen current recommendations and optimize patient care.

Repeated mechanical thrombectomy in short-term large vessel occlusion recurrence: multicenter study and systematic review of the literature

BACKGROUND

Data on the frequency and outcome of repeated mechanical thrombectomy (MT) in patients with short-term re-occlusion of intracranial vessels is limited. Addressing this subject, we report our multicenter experience with a systematic review of the literature.

METHODS

A retrospective analysis was conducted of consecutive acute stroke patients treated with MT repeatedly within 30 days at 10 tertiary care centers between January 2007 and January 2020. Baseline demographics, etiology of stroke, angiographic outcome and clinical outcome evaluated by the modified Rankin Scale (mRS) at 90 days were noted. Additionally, a systematic review of reports with repeated MT due to large vessel occlusion (LVO) recurrence was performed.

RESULTS

We identified 30 out of 7844 (0.4%) patients who received two thrombectomy procedures within 30 days due to recurrent LVO. Through systematic review, three publications of 28 participants met the criteria for inclusion. Combined, a total of 58 participants were analyzed: cardioembolic events were the most common etiology for the first (65.5%) and second LVO (60.3%), respectively. Median baseline NIHSS (National Institutes of Health Stroke Scale) was 13 (IQR 8-16) before the first MT and 15 (IQR 11-19) before the second MT (p=0.031). Successful reperfusion was achieved in 91.4% after the first MT and in 86.2% patients after the second MT (p=0.377). The rate of functional independence (mRS 0-2) was 46% at 90 days after the second procedure.

CONCLUSION

Repeated MT in short-term recurrent LVO is a rarity but appears to be safe and effective. The second thrombectomy should be pursued with the same extensive effort as the first procedure as these patients may achieve similar good outcomes.

Emergency carotid artery revascularization using Casper-RX stent: A single-center experience

BACKGROUND

Casper-RX (MicroVention, Aliso Viejo, California, USA) is a dual-layer closed cell stent recently introduced as a carotid artery revascularization device. Although its effectiveness and safety has been proved in elective cases, there are contradictive results regarding its patency in emergency settings. The purpose of the study is to present our single-center experience with the Casper-RX stent in the emergency interventions.

PATIENTS AND METHODS

Consecutive patients who underwent emergency carotid artery stenting using Casper-RX system with or without additional intracranial thrombectomy between August 2016 and June 2019 at our institution were included. Primary end point was the short-term patency of the carotid stents evaluated before hospital discharge by use of Doppler ultrasonography.

RESULTS

Twenty-nine procedures performed on 28 patients were included in the study. All stents were patent on final angiograms. Acute stent occlusion was observed only in one case (3.4%) with a spontaneous cervical internal carotid artery dissection the day after the procedure. In 26 (89.6%) cases, an additional intracranial thrombectomy was performed with a successful recanalization rate of 96.1%. Seven adverse events occurred peri-/post-procedural: two cases (6.9%) with iatrogenic dissection of distal cervical internal carotid artery during intracranial thrombectomy, two parenchymal hematoma type 2 (6.8%), and three patients (10.3%) developed massive infarction.

CONCLUSION

This study supports the safety and efficacy of the Casper-RX stent in emergency endovascular carotid artery revascularization procedures.