Anton Haass

Universität des Saarlandes, Saarbrücken, Saarland, Germany

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Publications (30)165.43 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Acute stroke is one of the main causes of death and chronic disability. Thrombolysis with recombinant tissue plasminogen activator within the first hours after onset of symptoms is an effective therapeutic option for ischemic stroke. However, fewer than 2% to 7% of patients receive this treatment, primarily because most patients reach the hospital too late for the initiation of successful therapy. Several measures can reduce detrimental delay until treatment. It is of importance to use continual public awareness campaigns to reduce delays in patients' alarm of emergency medical services. Further relevant measures are repetitive education of emergency medical services teams to ensure the systematic use of scales designed for recognition of stroke symptoms and the proper triage of patients to stroke centers. A most important time-saving measure is prenotification of the receiving hospital by the emergency medical services team. In the future, treatment already at the emergency site may allow more than a small minority of patients to benefit from available treatment.
    International Journal of Stroke 04/2014; · 2.75 Impact Factor
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    ABSTRACT: Acute stroke is one of the main causes of death and chronic disability. Thrombolysis, achieved by administering recombinant tissue plasminogen activator within 4.5 h, is an effective therapeutic option for ischemic stroke. However, less than 2-12 % of patients receive this treatment and a major reason is that most patients reach the hospital too late. Several time-saving measures should be implemented. Firstly, optimized and continual public awareness campaigns for patients should be initiated to reduce delays in notifying the emergency medical service. Secondly, emergency medical service personnel should develop protocols for prenotification of the receiving hospital. Other suggested measures involve educating emergency medical service personnel to systematically use scales for recognizing the symptoms of stroke and to triage patients to experienced stroke centers. In the future, administering treatment at the emergency site (mobile stroke unit concept) may allow more than a small minority of patients to benefit from available recanalization treatment options.
    Der Nervenarzt 11/2013; · 0.80 Impact Factor
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    ABSTRACT: Thrombolysis with alteplase administered within a narrow therapeutic window provides an effective therapy for acute ischaemic stroke. However, mainly because of prehospital delay, patients often arrive too late for treatment, and no more than 1-8% of patients with stroke obtain this treatment. We recommend that all links in the prehospital stroke rescue chain must be optimised so that in the future more than a small minority of patients can profit from time-sensitive acute stroke therapy. Measures for improvement include continuous public awareness campaigns, education of emergency medical service personnel, the use of standardised, validated scales for recognition of stroke symptoms and for triaging to the appropriate institution, and advance notification to the receiving hospital. In the future, use of telemedicine technologies for interaction between the emergency site and hospital, and the strategy of treatment directly at the emergency site (mobile stroke unit concept), could contribute to more efficient use of resources and reduce the time taken to instigate treatment to within 60 min-the golden hour-of the onset of the symptoms of stroke.
    The Lancet Neurology 06/2013; 12(6):585-596. · 23.92 Impact Factor
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    ABSTRACT: OBJECTIVES: This study sought to assess the feasibility and safety of a recently described technique of mechanical recanalization with the help of a stent-like device. BACKGROUND: In the special group of acute stroke patients with an intracranial large vessel occlusion, intravenous tissue-type plasminogen activator on its own leads to a good clinical outcome (mRS ≤2) in only 15% to 25% of cases. The aforementioned technique of mechanical recanalization showed very promising clinical results. METHODS: Forty patients presenting within 6 h from stroke symptom onset were enrolled. Mechanical recanalization was performed using a Solitaire FR revascularization device. The primary endpoint of the study was the clinical outcome rated with the help of the modified Rankin Scale (mRS) after 90 days. RESULTS: Twenty-four patients (60%) showed a good clinical outcome (mRS ≤2) at 90 days. One symptomatic hemorrhage was detected on follow-up computed tomography. The death rate was 12.5% (5 patients). Successful recanalization (Thrombolysis In Cerebral Infarction score ≥2b) of the target vessel was achieved in 95% of the patients with a mean of 1.8 runs with the device. CONCLUSIONS: The ReFlow (Mechanical Recanalization With Flow Restoration in Acute Ischemic Stroke) study shows that mechanical recanalization with flow restoration is highly effective in stroke patients with a large intracranial vessel occlusion presenting within 4.5 h after symptom onset. (Mechanical Recanalization With Flow Restoration in Acute Ischemic Stroke [ReFlow]; NCT01210729).
    JACC. Cardiovascular Interventions 03/2013; · 1.07 Impact Factor
  • Journal of the American College of Cardiology 07/2012; 60(5):e7. · 14.09 Impact Factor
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    ABSTRACT: In this feasibility study, we tested whether prehospital diagnostic stroke workup enables rational decision-making regarding treatment and the target hospital in persons with suspected stroke. A mobile stroke unit that delivers imaging (including multimodal brain imaging with CT angiography and CT perfusion), point-of-care-laboratory analysis, and neurologic expertise directly at the emergency site was analyzed for its use in prehospital diagnosis-based triage of suspected stroke patients. We present 4 complementary cases with suspected stroke who underwent prehospital diagnostic workup that enabled direct diagnosis-based treatment decisions and reliable triage regarding the most appropriate medical facility for that individual, e.g., a primary hospital vs specialized centers of a tertiary hospital. This preliminary report demonstrates the feasibility of prehospital diagnostic stroke workup for immediate etiology-specific decision-making regarding the necessary time-sensitive stroke treatment and the most appropriate target hospital.
    Neurology 05/2012; 78(23):1849-52. · 8.25 Impact Factor
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    ABSTRACT: Only 2-5% of patients who have a stroke receive thrombolytic treatment, mainly because of delay in reaching the hospital. We aimed to assess the efficacy of a new approach of diagnosis and treatment starting at the emergency site, rather than after hospital arrival, in reducing delay in stroke therapy. We did a randomised single-centre controlled trial to compare the time from alarm (emergency call) to therapy decision between mobile stroke unit (MSU) and hospital intervention. For inclusion in our study patients needed to be aged 18-80 years and have one or more stroke symptoms that started within the previous 2·5 h. In accordance with our week-wise randomisation plan, patients received either prehospital stroke treatment in a specialised ambulance (equipped with a CT scanner, point-of-care laboratory, and telemedicine connection) or optimised conventional hospital-based stroke treatment (control group) with a 7 day follow-up. Allocation was not masked from patients and investigators. Our primary endpoint was time from alarm to therapy decision, which was analysed with the Mann-Whitney U test. Our secondary endpoints included times from alarm to end of CT and to end of laboratory analysis, number of patients receiving intravenous thrombolysis, time from alarm to intravenous thrombolysis, and neurological outcome. We also assessed safety endpoints. This study is registered with ClinicalTrials.gov, number NCT00153036. We stopped the trial after our planned interim analysis at 100 of 200 planned patients (53 in the prehospital stroke treatment group, 47 in the control group), because we had met our prespecified criteria for study termination. Prehospital stroke treatment reduced the median time from alarm to therapy decision substantially: 35 min (IQR 31-39) versus 76 min (63-94), p<0·0001; median difference 41 min (95% CI 36-48 min). We also detected similar gains regarding times from alarm to end of CT, and alarm to end of laboratory analysis, and to intravenous thrombolysis for eligible ischaemic stroke patients, although there was no substantial difference in number of patients who received intravenous thrombolysis or in neurological outcome. Safety endpoints seemed similar across the groups. For patients with suspected stroke, treatment by the MSU substantially reduced median time from alarm to therapy decision. The MSU strategy offers a potential solution to the medical problem of the arrival of most stroke patients at the hospital too late for treatment. Ministry of Health of the Saarland, Germany, the Werner-Jackstädt Foundation, the Else-Kröner-Fresenius Foundation, and the Rettungsstiftung Saar.
    The Lancet Neurology 04/2012; 11(5):397-404. · 23.92 Impact Factor
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    ABSTRACT: The purpose of this study is to demonstrate the technical success of carotid artery stenting in acute extracranial internal carotid artery (ICA) occlusion as well as the benefit in clinical outcome. Stroke caused by acute occlusion of the ICA is associated with a significant level of morbidity and mortality. For this type of lesion, treatment with standard intravenous thrombolysis alone leads to a good clinical outcome in only 17% of the cases, with a death rate as high as 55%. Recanalization of the occluded ICA can lead to an improvement in acute symptoms of stroke, prevent possible deterioration, and reduce long-term stroke risk. At present, there is no consensus treatment for patients with acute ischemic stroke presenting with severe clinical symptoms due to atherosclerotic occlusion of the extracranial ICA. Carotid artery stenting was performed in 22 patients with acute atherosclerotic extracranial ICA occlusion within 6 h of stroke symptom onset. In 18 patients, there was an additional intracranial occlusion at the level of the terminal segment of the ICA (n = 4) and at the level of the middle cerebral artery (n = 14). Intracranial occlusions were either treated with the Penumbra system or the Solitaire stent-based recanalization system, or a combination of mechanical recanalization and intra-arterial thrombolysis. Recanalization results were assessed by angiography immediately after the procedure. The neurologic status was evaluated before and after the treatment with a follow-up as long as 90 days using the National Institutes of Health Stroke Scale and the modified Rankin Scale. Successful revascularization of extracranial ICA with acute stent implantation was achieved in 21 patients (95%). There was no acute stent thrombosis. After successful recanalization of the origin of the ICA, the intracranial recanalization with Thrombolysis In Myocardial Infarction flow grade 2/3 was achieved in 11 of the 18 patients (61%). The overall recanalization rate (extracranial and intracranial) was 14 of 22 patients (63%). Nine patients (41%) had a modified Rankin Scale score of ≤2 at 90 days. The mortality rate was 13.6% at 90 days. Carotid artery stenting in acute atherosclerotic extracranial ICA occlusion with severe stroke symptoms is feasible, safe, and useful within the first 6 h after symptom onset.
    Journal of the American College of Cardiology 11/2011; 58(23):2363-9. · 14.09 Impact Factor
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    ABSTRACT: [This corrects the article on p. e13758 in vol. 5.].
    PLoS ONE 01/2011; 6(3). · 3.73 Impact Factor
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    ABSTRACT: Currently, stroke laboratory examinations are usually performed in the centralized hospital laboratory, but often planned thrombolysis is given before all results are available, to minimize delay. In this study, we examined the feasibility of gaining valuable time by transferring the complete stroke laboratory workup required by stroke guidelines to a point-of-care laboratory system, that is, placed at a stroke treatment room contiguous to the computed tomography, where the patients are admitted and where they obtain neurological, laboratory, and imaging examinations and treatment by the same dedicated team. Our results showed that reconfiguration of the entire stroke laboratory analysis to a point-of-care system was feasible for 200 consecutively admitted patients. This strategy reduced the door-to-therapy-decision times from 84 ± 26 to 40 ± 24 min (p < 0.001). Results of most laboratory tests (except activated partial thromboplastin time and international normalized ratio) revealed close agreement with results from a standard centralized hospital laboratory. These findings may offer a new solution for the integration of laboratory workup into routine hyperacute stroke management.
    Annals of Neurology 12/2010; 69(3):581-6. · 11.19 Impact Factor
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    ABSTRACT: The purpose of this study was to assess the initial post-market experience of the device and how it is compared with the Penumbra Pivotal trial used to support the 510k application. A retrospective case review of 157 consecutive patients treated with the Penumbra system at seven international centers was performed. Primary endpoints were revascularization of the target vessel (TIMI score of 2 or 3), good functional outcome as defined by a modified Rankin scale (mRS) score of ≤2 and incidence of procedural serious adverse events. Results were compared with those of the Penumbra pivotal trial. A total of 157 vessels were treated. Mean baseline values at enrollment were: age 65 years, NIHSS score 16. After use of the Penumbra system, 87% of the treated vessels were revascularized to TIMI 2 (54%) or 3 (33%) as compared with 82% reported in the Pivotal trial. Nine procedural serious adverse events were reported in 157 patients (5.7%). All-cause mortality was 20% (32/157), and 41% had a mRS of ≤2 at 90-day follow-up as compared with only 25% in the Pivotal trial. Patients who were successfully revascularized by the Penumbra system had significantly better outcomes than those who were not. Initial post-market experience of the Penumbra system revealed that the revascularization rate and safety profile of the device are comparable to those reported in the Pivotal trial. However, the proportion of patients who had good functional outcome was higher than expected.
    Journal of neurointerventional surgery 12/2010; 2(4):341-4. · 1.38 Impact Factor
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    ABSTRACT: The purpose of this study was to demonstrate a new approach to the use of a self-expanding stent in the treatment of acute ischemic stroke. Twenty-two consecutive patients with acute intracerebral artery occlusions were treated with a self-expandable intracranial stent, which was withdrawn in its unfolded state. For this technique, we used the Solitaire AB/FR, which is the only intracranial stent that is fully recoverable. Eight patients had an occlusion of the basilar artery, 12 had a middle cerebral artery occlusion, and 2 had terminal carotid artery occlusions; 6 of these had to be treated first for an acute occlusion originating in the internal carotid artery. Recanalization results were assessed by follow-up angiography immediately after the procedure. Neurologic status was evaluated before and after treatment (90-day follow-up) according to the National Institutes of Health Stroke Scale and modified Rankin scale. Successful revascularization was achieved in 20 of 22 (90.9%) patients (thrombolysis in cerebral infarction [TICI] 2a/b and 3), a TICI 3 state was accomplished in 12 patients, and partial recanalization or slow distal branch filling with filling of more than two-thirds of the vessel territory was achieved in 8 patients (TICI 2b). There was immediate flow restoration in 21 of 22 (95.4%) cases after deployment of the device. The stent was removed in its unfolded state in all patients. The mean time from stroke symptom onset to recanalization was 277 minutes, with a standard deviation of 118 minutes. Mean National Institutes of Health Stroke Scale score on admission was 19.4, with a standard deviation of 5.7. Almost two-thirds of the patients (63.6%) improved by > 10 points on the National Institutes of Health Stroke Scale at discharge, and 50% showed a modified Rankin scale score of ≤ 2 at 90 days (59% with a modified Rankin scale ≤ 3). Mortality was 18.1%. In 1 case, an asymptomatic intracranial hemorrhage was detected on control computed tomography, and 2 patients had a symptomatic intracranial hemorrhage. Withdrawal of an unfolded, fully recoverable, intracranial stent yielded very promising angiographic and clinical results. It combines the advantages of prompt flow restoration and mechanical thrombectomy.
    Stroke 11/2010; 41(11):2559-67. · 6.16 Impact Factor
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    Circulation 06/2010; 121(23):2605-6. · 15.20 Impact Factor
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    ABSTRACT: To evaluate the recanalization rate and clinical outcome in children with acute ischemic stroke following treatment with innovative mechanical thrombectomy devices. Patients and 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. 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. 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.
    The Journal of invasive cardiology 02/2010; 22(2):63-6. · 1.57 Impact Factor
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    ABSTRACT: 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. 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. 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. 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.
    Neuroradiology 01/2010; 52(1):61-6. · 2.70 Impact Factor
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    ABSTRACT: Early treatment with rt-PA is critical for favorable outcome of acute stroke. However, only a very small proportion of stroke patients receive this treatment, as most arrive at hospital too late to be eligible for rt-PA therapy. We developed a "Mobile Stroke Unit", consisting of an ambulance equipped with computed tomography, a point-of-care laboratory system for complete stroke laboratory work-up, and telemedicine capabilities for contact with hospital experts, to achieve delivery of etiology-specific and guideline-adherent stroke treatment at the site of the emergency, well before arrival at the hospital. In a departure from current practice, stroke patients could be differentially treated according to their ischemic or hemorrhagic etiology even in the prehospital phase of stroke management. Immediate diagnosis of cerebral ischemia and exclusion of thrombolysis contraindications enabled us to perform prehospital rt-PA thrombolysis as bridging to later intra-arterial recanalization in one patient. In a complementary patient with cerebral hemorrhage, prehospital diagnosis allowed immediate initiation of hemorrhage-specific blood pressure management and telemedicine consultation regarding surgery. Call-to-therapy-decision times were 35 minutes. This preliminary study proves the feasibility of guideline-adherent, etiology-specific and causal treatment of acute stroke directly at the emergency site.
    PLoS ONE 01/2010; 5(10):e13758. · 3.73 Impact Factor
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    ABSTRACT: 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.
    Neuroradiology 11/2009; · 2.70 Impact Factor
  • Archives of neurology 07/2009; 66(6):800-1. · 7.58 Impact Factor
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    ABSTRACT: This is the first single center experience illustrating the effectiveness of the penumbra system (PS) in the treatment of large vessel occlusive disease in the arena of acute ischaemic stroke. The PS is an innovative mechanical thrombectomy device, employed in the revascularization of large cerebral vessel occlusions in patients via the utilization of an aspiration platform. This is a prospective, non-randomized controlled trial evaluating the clinical and functional outcome in 29 patients with acute intra-cranial occlusions consequent to mechanical thrombectomy by the PS either as mono-therapy or as an adjunct to current standard of care. Patients were evaluated by a neurologist and treated by our in house interventional neuro-radiologists. Primary end-points were revascularization of the occluded target vessel to TIMI grade 2 or 3 and neurological outcome as measured by an improvement in the NIH Stroke Scale (NIHSS) score after the procedure. Complete revascularization (TIMI 3) was achieved in 21/29 (72.4%) of patients. Partial revascularization (TIMI 2) was established in 4/29 (13.8%) of patients. Revascularization failed in four (13.8%) patients. Nineteen (19) patients (65.5%) had at least a four-point improvement in NIHSS scores. Modified Rankin scale scores of < or =2 were seen in 37.9% of patients. There were no device-related adverse events. Symptomatic intra-cranial hemorrhage occurred in 7% of patients. The PS has the potential of exercising a significant impact in the interventional treatment of ischaemic stroke in the future.
    European Journal of Neurology 07/2009; 16(11):1210-6. · 4.16 Impact Factor
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    ABSTRACT: For patients with acute ischemic stroke due to total occlusion of the internal carotid artery (ICA), an effective intervention to improve neurologic symptoms and clinical outcome has not yet been established. Some authors have reported successful revascularization for patients with acute stroke symptoms secondary to ICA occlusion only in isolated series and case reports. Emergency recanalization and carotid artery stent placement can improve neurologic outcome in selected patients with acute ischemic stroke and total occlusion of the ICA.
    Der Radiologe 05/2009; 49(4):335-9. · 0.47 Impact Factor

Publication Stats

263 Citations
165.43 Total Impact Points

Institutions

  • 2006–2012
    • Universität des Saarlandes
      • Klinik für Diagnostische und Interventionelle Neuroradiologie
      Saarbrücken, Saarland, Germany
  • 2010
    • Cleveland State University
      Cleveland, Ohio, United States
  • 2009
    • Oxford University Hospitals NHS Trust
      Oxford, England, United Kingdom
  • 2004
    • Kazan State Medical University
      Kasan, Tatarstan, Russia