Impact of mobile stroke units.

Since its first introduction in clinical practice in 2008, the concept of mobile stroke unit enabling prehospital stroke treatment has rapidly expanded worldwide. This review summarises current knowledge in this young field of stroke research, discussing topics such as benefits in reduction of delay before treatment, vascular imaging-based triage of patients with large-vessel occlusion in the field, differential blood pressure management or prehospital antagonisation of anticoagulants. However, before mobile stroke units can become routine, several questions remain to be answered. Current research, therefore, focuses on safety, long-term medical benefit, best setting and cost-efficiency as crucial determinants for the sustainability of this novel strategy of acute stroke management.

Prehospital Computed Tomography Angiography in Acute Stroke Management.

BACKGROUND: An ambulance equipped with a computed tomography (CT) scanner, a point-of-care laboratory, and telemedicine capabilities (mobile stroke unit [MSU]) has been shown to enable the delivery of thrombolysis to stroke patients directly at the emergency site, thereby significantly decreasing time to treatment. However, work-up in an MSU that includes CT angiography (CTA) may also potentially facilitate triage of patients directly to the appropriate target hospital and specialized treatment, according to their individual vascular pathology. METHODS: Our institution manages a program investigating the prehospital management of patients with suspicion of acute stroke. Here, we report a range of scenarios in which prehospital CTA could be relevant in triaging patients to the appropriate target hospital and to the individually required treatment. RESULTS: Prehospital CTA by use of an MSU allowed to detect large vessel occlusion of the middle cerebral artery in one patient with ischemic stroke and occlusion of the basilar artery in another, thereby allowing rational triage to comprehensive stroke centers for immediate intra-arterial treatment. In complementary cases, prehospital imaging not only allowed diagnosis of parenchymal hemorrhage with a spot sign indicating ongoing bleeding in one patient and of subarachnoid hemorrhage in another but also clarified the underlying vascular pathology, which was relevant for subsequent triage decisions. CONCLUSION: Defining the vascular pathology by CTA directly at the emergency site may be beneficial in triaging patients with various cerebrovascular diseases to the most appropriate target hospital and specialized treatment.

First Automated Stroke Imaging Evaluation via Electronic Alberta Stroke Program Early CT Score in a Mobile Stroke Unit.

BACKGROUND: Recently, a mobile stroke unit (MSU) was shown to facilitate acute stroke treatment directly at the emergency site. The neuroradiological expertise of the MSU is improved by its ability to detect early ischemic damage via automatic electronic (e) evaluation of CT scans using a novel software program that calculates the electronic Alberta Stroke Program Early CT Score (e-ASPECTS). METHODS: The feasibility of integrating e-ASPECTS into an ambulance was examined, and the clinical integration and utility of the software in 15 consecutive cases evaluated. RESULTS: Implementation of e-ASPECTS onto the MSU and into the prehospital stroke management was feasible. The values of e-ASPECTS matched with the results of conventional neuroradiologic analysis by the MSU team. The potential benefits of e-ASPECTS were illustrated by three cases. In case 1, excluding early infarct signs supported the decision to directly perform prehospital thrombolysis. In case 2, in which stroke was caused by large-vessel occlusion, the high e-ASPECTS value supported the decision to initiate intra-arterial treatment and triage the patient to a comprehensive stroke center. In case 3, the e-ASPECTS value was 10, indicating the absence of early infarct signs despite pre-existing cerebral microangiopathy and macroangiopathy, a finding indicating the program's robustness against artefacts. CONCLUSIONS: This study on the integration of e-ASPECTS into the prehospital stroke management via a MSU showed for the first time that such integration is feasible, and aids both decision regarding the treatment option and the triage regarding the most appropriate target hospital.

Treatment of elastase-induced intracranial aneurysms in New Zealand white rabbits by use of a novel neurovascular embolization stent device.

INTRODUCTION: This study aims to test a novel balloon expandable stent covered with a polytetrafluoroethylene membrane (neurovascular embolization cover (NEC), NFocus Neuromedical, Palo Alto, California) regarding angiographic and histologic aneurysm occlusion. Radiopacity, stent placement, navigation, flexibility, and intimal proliferation were also evaluated. METHODS: Eight aneurysms were induced in New Zealand white rabbits. Digital subtraction angiography (DSA) was performed directly after stent placement and after 5 and 10 min. Four and 8 weeks after stent placement, an intra-arterial DSA control was performed. The animals were then sacrificed and the aneurysms histologically evaluated. RESULTS: The radiopaque markers were clearly visible. Although all the stents were easily navigated into the subclavian artery, the limited flexibility of the stent resulted in straightening of the vessel in four cases. As a result, exact stent placement was achieved and acutely confirmed in only two cases. However, at sacrifice, angiographic and histologic occlusion was noted at follow-up in five aneurysms. CONCLUSION: In tortuous anatomy, the relative stiffness of the stent makes exact stent placement challenging. This may have been exacerbated by the movement of the vessels due to proximity to the heart in this model. Future studies should evaluate whether existing residual flow into an aneurysm lumen might lead to embolization without any additional treatment. Anticoagulation remains a very important part of aneurysm treatment with stents. The trend toward aneurysm occlusion by excluding it from the blood circulation seems a promising method in future endovascular therapy. The NEC device shows good potential.

Simple measurement of aneurysm residual after treatment: the SMART scale for evaluation of intracranial aneurysms treated with flow diverters.

BACKGROUND: Primary 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. METHOD: A 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]. FINDINGS: Grade 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. CONCLUSIONS: Further 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 carotid artery stenting on cognitive function.

INTRODUCTION: There have only been a few studies on cognitive changes in patients with carotid occlusive disease, and the results of these show major discrepancies in the extent to which treatment affects neuropsychological function. We sought to clarify these discrepancies by evaluating the effects of carotid artery stenting (CAS) on the cognitive function. METHODS: Forty-one asymptomatic CAS patients were administered a test battery of neuropsychological tests measuring cognitive speed and memory function before and 3 months after the procedure. A control group was also evaluated. To test for thromboembolic lesions, diffusion-weighted imaging was used. RESULTS: CAS led to a significant increase in cognitive speed (p<0.001) but did not afford any change in memory function. This was regardless of the degree or side of stenosis or patient age or gender. CONCLUSION: CAS significantly improved functions that involve cognitive speed. Earlier studies did not differentiate between speed and memory tests and thus might have missed these changes. Further studies correlating changes in brain perfusion with increase in cognitive speed are needed.

Progressive Cerebral Small Vessel Disease Caused by an Autoimmune Response to Intravesical Bacille-Calmette-Guérin Treatment.

Systemic BCGitis and autoimmune diseases are possible adverse events of intravesical Bacille Calmette-Guérin-(BCG)-instillations in the treatment of urothelioma cancer. We present the case of an 83-years-old male patient with rapid progressive symptoms of dementia up to mutism as well as tonic seizures. Immune-mediated cerebral small vessel disease was diagnosed and retraced to former instillations of BCG. Intense immunosuppressive treatment was performed and clinical restoration was achieved within several months. While cerebral vasculitis due to BCGitis has already been described before, this is to our knowledge the first case report to illustrate an immune-mediated small vessel disease after BCG-instillations. This should be considered in patients with rapidly progressive dementia-like symptoms treated with BCG, as an immunosuppressive treatment can be highly effective even at severe clinical stages.

Proximal protection with the Gore PAES can reduce DWI lesion size in high-grade stenosis during carotid stenting.

AIMS: The aim was to determine the incidence of new ischaemic lesions on diffusion-weighted MR imaging (DWI) in a non-randomised cohort of patients after protected and unprotected carotid artery stent placement using the Parodi Anti-Emboli System (PAES). METHODS AND RESULTS: A retrospective review was conducted on 269 patients who received DWI prior to, and 24-72 hours after, stent placement. All patients were enrolled in one centre. Forty patients stented with the PAES device were matched with 229 patients stented without protection (control group). New diffusion restriction on DWI was detected in 25.8% (PAES) versus 32.3% (control group); p=0.64. On average there were 0.7 lesions (PAES) versus 0.8 lesions (control group) per patient. The area of lesions was 1.7 (PAES) versus 5.6 mm2. In a subanalysis of patients (32 PAES, 148 non-protected) with >80% stenosis, the area of restricted diffusion was less when proximal protection was used (p<0.05). The number and area of DWI lesions did not differ on the contralateral, non-stented side. When the PAES system was used, patients were more likely not to have any lesion at all (p=0.028). CONCLUSIONS: In high-grade stenosis, the use of the Gore PAES device significantly reduced the area of new DWI lesions and patients were more likely not to have any new DWI lesion at all.

Current management and treatment of cerebral vasospasm complicating SAH.

Cerebral vasospasm is a common and serious complication of aneurysmal subarachnoid haemorrhage. Despite the improvements in treatment of aneurysmal subarachnoid haemorrhage (aSAH), cerebral vasospasm complicating aSAH has remained the main cause of morbidity and mortality. Subarachnoid haemorrhage (SAH)-induced vasospasm is a complex entity caused by vasculopathy, impaired autoregulation, and hypovolaemia, causing a regional reduction of cerebral brain perfusion which can then induce ischaemia. Cerebral vasospasm can present either asymptomatically detected only radiologically or symptomatically (delayed ischaemic neurologic deficit). The various diagnostic approaches include the use of transcranial doppler, digital subtraction angiography and multimodal computed tomography (CT) and magnetic resonance (MR) techniques. Although digital subtraction angiography is usually the gold standard for the diagnosis of cerebral vasospam, transcranial doppler is commonly the first-screening method for the detection of cerebral vasospam. The treatment of subarachnoid haemorrhage -induced vasospasm include the use of both medical and endovascular therapy. The aim of this review is to discuss the various current therapeutic options and future perspective measures for reducing cerebral vasospasm induced stroke after SAH.

Current pediatric stroke treatment.

BACKGROUND: The treatment of stroke in children and infants is essential, but unfortunately is not supported by factual and substantiated data. METHODS: This is a comprehensive review of the currently published data on acute ischemic stroke treatment in children and highlights recent advances and possibilities with mechanical devices in the treatment of stroke in this vulnerable age population. RESULTS: The current treatment for most children with acute ischemic stroke is limited to the management of the symptoms. Mechanical recanalization may improve recanalization rates and clinical outcomes. CONCLUSIONS: Although clinical trials will be difficult to establish in children, continued research and additional experience are imperative to treat this often devastating condition.

New mechanical recanalization devices - the future in pediatric stroke treatment?

OBJECTIVE: To evaluate the recanalization rate and clinical outcome in children with acute ischemic stroke following treatment with innovative mechanical thrombectomy devices. PATIENTS AND METHODS: Three subjects aged 7-16 years presenting with acute cerebral vascular occlusions (thrombolysis in myocardial infarction [TIMI] 0) were treated with either the Penumbra System, operating on an aspiration platform, or the Phenox clot retriever device, a flexible wire compound with perpendicularly-oriented polyamid microfilaments. Target vessels were the internal carotid artery, the middle cerebral artery and the basilar artery. RESULTS: Successful recanalization (TIMI 3) was attained in all cases. No device-related complications or intracranial hemorrhage occurred. Follow up was conducted for up to 30 days. A 10- to 26-point improvement in the National Institutes of Health Stroke Scale (NIHSS) score was achieved. CONCLUSIONS: Mechanical thrombectomy devices possess a dual advantage whereby they can achieve instant recanalization as well as minimize the number of bleeds that customarily accompany intravenous and intra-arterial therapy. These new devices could contribute greatly to treatment decisions in a field not yet clearly defined by current guidelines.

Endovascular treatment of unruptured intracranial aneurysms: occurrence of thromboembolic events.

OBJECTIVE: The purpose of this study was to evaluate the frequency and causes of thromboembolic events associated with endovascular embolization of asymptomatic aneurysms. Correlations between radiological findings (aneurysm size, localization, embolization time, number of coils used, as well as patient age) were evaluated with the occurrence of thromboembolic events and clinical findings. METHODS: Sixty-eight patients treated for unruptured intracranial aneurysms (mean age, 49 yr) were evaluated. Hyperintense lesions on diffusion weighted imaging were analyzed in 50 patients. Aneurysm size was 3 to 15 mm. RESULTS: Complete occlusion of the aneurysms was achieved in 55 of 68 (82%). One patient had a transient paresis. There was one infarction and one aneurysm rupture during the procedure with no consecutive neurological symptoms. We found new hyperintense lesions in 21 of 50 (42%) diffusion weighted imaging studies. In 43% of these, there was only one lesion smaller than 2 mm. In 33%, there was more than one lesion less than 2 mm; in 19%, we found a lesion of 2 to 10 mm in size. In one case, a lesion greater than 10 mm occurred. There was no correlation between aneurysm location and the occurrence of lesions or among the number of coils used, the size of the aneurysm, patient age, or embolization time. Mortality rate was 0%, morbidity 4.0%. If the 18 aneurysms where no diffusion weighted imaging was obtained are included, morbidity is 2.9%. CONCLUSION: The high rate of thromboembolic events suggests that heparin is not sufficient to prevent ischemic lesions. An antiplatelet therapy, started before or during intervention, might diminish thrombus formation.

Anticoagulation regimes and their influence on the occlusion rate of aneurysms: an experimental study in rabbits.

OBJECTIVE: Our purpose was to determine whether anticoagulation has an influence on the occlusion rate and thromboembolic occurrence in saccular aneurysms treated with Guglielmi detachable coils. METHODS: Aneurysms in the right CCA were created in rabbits. Group 1 served as a control group (n = 6) without embolization or anticoagulation. In Groups 2 to 5, aneurysms were embolized. In Group 2, no anticoagulation was given (n = 5). Group 3 received heparin before the placement of the first coil, then low molecular weight heparin (LMWH) for the next 2 days (n = 7). In Group 4, additional aspirin was administered after 2 days until sacrifice (n = 10). Group 5 received heparin before the placement of the first coil, then a LMHW was administered daily until sacrifice (n = 5). Angiography was performed 3 months after coiling, followed by a histological examination. RESULTS: Histopathological evaluation showed thrombus formation with neovascularization, regardless of the anticoagulation regime used. Only in the group with LMWH over 3 months was the thrombus not focally, properly organized, especially in the dome. The coils in the neck showed, however, the same fibrous scar tissue as in the other groups. CONCLUSION: Anticoagulation with heparin during the first days, followed by aspirin, appears unlikely to affect the occlusion rate in aneurysms. LMWH over a long period, however, could impair thrombus organization. Therefore, in regard to thrombus organization, an anticoagulation regime with aspirin seems to be superior to LMWH. This could play an important role in the prevention of thromboembolic events in humans treated with Guglielmi detachable coils.