Anna Luisa Kühn

Reduction in Distal Emboli With Proximal Flow Control During Mechanical Thrombectomy: A Quantitative In Vitro Study

Background and Purpose— To evaluate the impact of proximal flow control on efficacy and safety of mechanical thrombectomy in an in vitro middle cerebral artery occlusion. Methods— Three independent variables, including clot type, device (Merci Retriever, Solitaire FR, and Trevo devices), and use of a balloon guide catheter, were used to ascertain the impact of proximal flow control on the size and number of distal emboli generated during thrombectomy. Secondary end points were the recanalization rate and amount of flow restored. Results— Use of the balloon guide catheter during thrombectomy of the fragile, hard clot significantly reduced the formation of large distal emboli with a diameter >1 mm, regardless of the device used (P<0.01). Applying aspiration via the balloon guide catheter in place of the conventional guide catheter resulted in a significant increase of flow reversal (P<0.0001). Prior to thrombectomy, deployment of the stent-trievers produced immediate flow restoration through the soft and hard clot occlusions, 69.2±27.3 and 45.5±22.8 mL/min, respectively, that was preserved after the balloon inflation because of collateral flow via the posterior communication artery. After deployment but before thrombectomy, no flow was restored when using the Merci Retriever. After thrombectomy, complete flow restoration was achieved in a majority of cases. The Merci Retriever required more thrombectomy attempts to achieve hard clot removal compared with the stent-trievers when the conventional guide catheter was used (1.5 versus 1.1). Conclusions— The risk of distal embolization was significantly reduced with the use of the balloon guide catheter.

Hyperperfusion syndrome after carotid stent angioplasty.

IntroductionThis study assesses the incidence and causes of hyperperfusion syndrome occurring after carotid artery stenting (CAS).Materials and methodsWe retrospectively reviewed the clinical database of 417 consecutive patients who were treated with CAS in our department to identify patients who developed hyperperfusion syndrome and/or intracranial hemorrhage. Magnetic resonance imaging (MRI) including fluid-attenuated inversion recovery and diffusion-weighted imaging was performed before and after CAS in 269 cases. A Spearman’s rho nonparametric correlation was performed to determine whether there was a correlation between the occurrence/development of hyperperfusion syndrome and the patient’s age, degree of stenosis on the stented and contralateral side, risk factors such as diabetes, smoking, hypertension, adiposity, gender and fluoroscopy time, and mean area of postprocedural lesions as well as preexisting lesions. Significance was established at p < 0.05.ResultsOf the 417 carotid arteries stented and where MRI was also completed, we found hyperperfusion syndrome in 2.4% (ten cases). Patients who had preexisting brain lesions (previous or acute stroke) were at a higher risk of developing hyperperfusion syndrome (p = 0.022; Spearman’s rho test). We could not validate any correlation with the other patient characteristics.ConclusionExtensive microvascular disease may be a predictor of hyperperfusion syndrome after carotid stent placement. We believe that further studies are warranted to predict more accurately which patients are at greater risk of developing this often fatal complication.

ARTS (Aspiration-Retriever Technique for Stroke): Initial clinical experience.

Background A new generation of highly navigable large-bore aspiration catheters and retriever devices for intracranial mechanical thrombectomy has markedly improved recanalization rates, time and clinical outcomes. We report collected clinical data utilizing a new technique based on combined large lumen aspiration catheter and partially resheathed stent retriever (ARTS: Aspiration (catheter)–(stent) Retriever Technique for Stroke). This technique is applied, especially in presence of bulky/rubbery emboli, when resistance is felt while retracting the stent retriever; at that point the entire assembly is locked and removed in-toto under continuous aspiration with additional flow arrest. Methods A retrospective data analysis was performed to identify patients with large cerebral artery acute ischemic stroke treated with ARTS. The study was conducted between August 2013 and February 2015 at a single high volume stroke center. Procedural and clinical data were captured for analysis. Results Forty-two patients (median age 66 years) met inclusion criteria for this study. The ARTS was successful in achieving Thrombolysis in Cerebral Infarction (TICI) ≥2b revascularization in 97.6% of cases (TICI 2b = 18 patients, TICI 3 = 23 patients). Patients’ median National Institutes of Health Stroke Scale score at admission was 18 (6–40). A 3-month follow-up modified Rankin Scale value of 0–2 was achieved in 65.7% of the successfully treated patients (average 2.4). Two patients (4.8%) developed symptomatic intraparenchymal hemorrhages. Six procedure unrelated deaths were observed. Conclusions We found that ARTS is a fast, safe and effective method for endovascular recanalization of large vessel occlusions presenting within the context of acute ischemic stroke.

Endovascular treatment of tandem vascular occlusions in acute ischemic stroke.

Background and purpose Tandem vascular occlusions are an important cause of acute ischemic stroke (AIS) and present unique treatment challenges. We report our experience of managing a subset of AIS patients with extracranial vascular stenting/angioplasty and intracranial revascularization. Methods Consecutive patients who presented at three centers with AIS from tandem vascular occlusions confirmed by brain and neck CT imaging were included in the study. We retrospectively analyzed the patient demographics, National Institute of Health Stroke Scale (NIHSS) score and modified Rankin Scale (mRS) score at the time of admission, treatment strategy, angiographic results using the Thrombolysis In Cerebral Infarction (TICI) score, and clinical and imaging follow-up. Results Twenty-eight patients were included. The mean NIHSS score at admission was 18. Extracranial carotid occlusions with a concomitant middle cerebral artery occlusion were seen in 89.3% of patients (n=25) and vertebral artery combined with basilar artery lesions in 10.7% (n=3). An antegrade approach (ie, treatment of the extracranial lesion first) was used in 24 patients (85.7%). Proximal occlusion recanalization was achieved usually with a stent (n=27; 96.4%). Pursuant to intracranial revascularization techniques, ≥TICI 2A recanalization was seen in 96.4% of patients. An mRS score of ≤2 at 90 days was achieved in 56.5% of patients. Conclusions Our study shows preliminary data from three centers on recanalization of tandem occlusions in patients presenting with AIS. There was a preference to revascularize the proximal occlusion using a stent followed by distal recanalization with mechanical thrombectomy, intra-arterial thrombolysis or a combination of these. This approach has low periprocedural complications and can achieve an excellent angiographic and clinical outcome.

Endovascular Stroke Treatment Today

SUMMARY: The purpose of this study was to review current treatment options in acute ischemic stroke, focusing on the latest advances in the field of mechanical recanalization. These devices recently made available for endovascular intracranial thrombectomy show great potential in acute stroke treatments. Compelling evidence of their recanalization efficacy comes from current mechanical embolectomy trials. In addition to allowing an extension of the therapeutic time window, mechanical recanalization devices can be used without adjuvant thrombolytic therapy, thus diminishing the intracranial bleeding risk. Therefore, these devices are particularly suitable in patients in whom thrombolytic therapy is contraindicated. IV and IA thrombolysis and bridging therapy are viable options in acute stroke treatment. Mechanical recanalization devices can potentially have a clinically relevant impact in the interventional treatment of stroke, but at the present time, a randomized study would be beneficial.

Flow diverter stents for unruptured saccular anterior circulation perforating artery aneurysms: safety, efficacy, and short-term follow-up

Background Anterior circulation perforating artery aneurysms including anterior choroidal artery and lenticulostriate artery aneurysms are rare. Injury to these vessels can lead to severe debilitating symptoms. Objective To present a new approach to treatment using flow diversion technology. Methods Patients treated with a Pipeline embolization device (PED) for perforator artery aneurysms at our institution between June 2012 and May 2013 were identified and included in our retrospective analysis. We evaluated patient vascular risk factors; family history of aneurysms; aneurysm characteristics; National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) on admission; and angiography follow-up and patient clinical outcome at discharge, 6 months, and 1 year. Results We included four patients with a mean age of 59.8 years. Two patients had a positive family history of aneurysms. Patient vascular risk factors included smoking, dyslipidemia, and hypertension. All patients presented with a NIHSS and mRS of 0 on admission. Aneurysms were located at the anterior choroidal (n=2) or lenticulostriate artery (n=2) and were treated with a single PED. No periprocedural or postprocedural complications occurred. The patients were discharged with no change in NHISS or mRS score. Six-month and 1-year follow-up angiography showed complete aneurysm occlusion. Mild intimal hyperplasia was seen in 2 cases at 6 months, but was resolved at the 1-year follow-up. No re-treatment was necessary. NIHSS and mRS remained 0 at follow-up time points. Conclusions Our preliminary results show that flow diversion technology is an effective and safe therapy for complex, hard-to-treat aneurysms in perforating arteries. Larger studies with long-term follow-up are needed to validate our promising results.

Simple Measurement of Aneurysm Residual after Treatment: the SMART scale for evaluation of intracranial aneurysms treated with flow diverters

BackgroundPrimary endovascular reconstruction with flow diversion represents a fundamental paradigm shift in the technique of endovascular aneurysm treatment. Unlike coil embolization, often there remains residual post-procedural filling within the aneurysm with flow diverters, the curative reconstruction presumably occurring over a period of weeks. Thus, conventional grading scales for post-procedural aneurysm occlusion and recanalization are inadequate. The aim of this paper is to propose a new angiographic grading scale that addresses this fundamentally new treatment option.MethodA five-point grading scale describes the location of residual flow within the aneurysm in the venous phase [grade 1: patent aneurysm with diffuse inflow; grade 2: residual filling of the aneurysm dome (saccular) or wall (fusiform); grade 3: only residual neck (saccular) or only intra-aneurysmal filling with former boundaries covered (fusiform); grade 4: complete occlusion].FindingsGrade 0 represents any aneurysm, regardless of occlusion rate with early phase, coherent inflow jet. Intra-aneurysmal flow stagnation is categorized into: (a) none, (b) capillary phase, and (c) venous phase. Prevailing parent vessel hemodynamics with in-stent stenosis (ISS) are divided into none (ISS0), mild (ISS1), moderate (ISS2), severe (ISS3), and total (ISS4) occlusion. The proposed grading scales allow assessment of the hemodynamic consequences of stent placement on endosaccular in-flow, stasis, and location of stasis as well as parent vessel hemodynamics.ConclusionsFurther studies need to show the applicability and possible predictive value of this new grading scale on the efficacy of the stent in promoting intra-aneurysmal flow stagnation, thus creating the potential to harmonize the results of future papers. This may help to optimize treatment and future device design.

Influence of coil geometry on intra-aneurysmal packing density: evaluation of a new primary wind technology.

Introduction: This prospective randomized double-blinded in-vitro study was conducted to determine the relative Packing Density (PD) of the new Deltapaq coil (Micrus Endovascular) as compared to Micrus’s conventional filling CHE (Helipaq) and finishing CFS (Ultipaq) coils. Methods: Two physicians independently deployed the coils under fluoroscopy into a 4mm berry shaped glass aneurysm. Each coil tested was a 4mm × 35cm coil specially made for this study. Physicians and observer were blinded as to the type of coil. Five samples per group, per operator, were deployed. Results: mean PD were 36.6% (Helipaq), 37.9% (Ultipaq) and 40.4% (Deltapaq). Two-sample T-test showed a significantly higher PD of Deltapaq versus Helipaq (p < 0.022). Discussion: Higher coil PD and better neck coverage may provide an increased biomechanical stability and may potentially reduce the recanalization rate of aneurysms. Conclusion: The new Deltapaq coil may have the potential to achieve higher packing densities in the treatment of aneurysms.

Endovascular reconstruction of unruptured intradural vertebral artery dissecting aneurysms with the Pipeline embolization device

Background Dissecting aneurysms of the vertebral artery (VA) are difficult to treat using current surgical and endovascular techniques. Objective To analyze retrospectively the efficacy and safety of flow diverters in the treatment of dissecting aneurysms of the vertebral artery. Methods We identified six patients with six unruptured VA dissecting aneurysms either arising from the V4 or V3–V4 junction that were treated with the Pipeline embolization device (PED) at our institution between July 2012 and February 2015. Among other parameters, technical feasibility of the procedure, procedure-related complications, angiographic results, and clinical outcome were evaluated. Results PED placement was achieved in all cases and immediate angiography follow-up demonstrated intra-aneurysmal contrast stasis with parent artery preservation. A temporary episode of dysarthria was noted in one patient. Major procedure-related complications were not observed. The 6-month follow-up (n=6) demonstrated complete/near-complete aneurysm obliteration in five patients and partial obliteration in one. At the 1-year follow-up (n=5) stable complete aneurysm occlusion was seen in two patients. Two cases showed progression from near complete occlusion and partial occlusion at 6 months to complete occlusion and near complete occlusion. One cases showed unchanged near complete occlusion. No aneurysmal bleeding, in-stent stenosis or thromboembolic complication was seen. National Institutes of Health Stroke Scale and modified Rankin scale scores remained unchanged from admission to discharge. Conclusions Our preliminary experience with the use of PED for the treatment of intradural VA dissecting aneurysms shows promising short-term results, making this technique a feasible and safe treatment option in patients suitable for this approach. However, long-term and larger cohort studies are needed to validate these results.

Comparison of Stent Free Cell Area and Cerebral Lesions after Unprotected Carotid Artery Stent Placement

OBJECTIVE This study evaluates the correlation between closed, semi-closed and open-cell stent design and the association between stent type and clinical outcome as well as magnetic resonance imaging (MRI) findings. DESIGN A total of 194 patients who underwent unprotected carotid artery stenting (CAS) as well as diffusion-weighted magnetic resonance imaging (DW-MRI) before and after intervention were retrospectively reviewed. MATERIALS AND METHODS Three stent designs were studied: closed cell, semi-closed cell and open cell. Spearmans Rho test was performed between the stent free cell area and the number and area of ischaemic lesions found after intervention. Adverse events were evaluated. RESULTS There was no significant difference in clinical outcome between the three stent groups (Zilver, Cook Europe, Denmark; Smart, Codman, MA; and Wallstent, Stryker, MN, USA). A significant correlation was found between the stent free cell area and the number and area of new ischaemic lesions on DW-MRI (P = 0.023). There were significantly fewer new lesions with an open-cell design (Zilver; 12.76 mm(2) free cell area) than with a closed-cell design (Wallstent; 1.08 mm(2) free cell area). CONCLUSIONS Open-cell stent was related to a lower number and area of silent cerebral ischaemic lesions after unprotected CAS. However, clinical outcome, measured by incidence of adverse events and clinical neurologic assessment, was not significantly different between patients with different stent designs.