Anton Haass

Universität des Saarlandes, Saarbrücken, Saarland, Germany

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Publications (39)219.46 Total impact

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    ABSTRACT: Background: For patients with acute ischemic stroke, intra-arterial treatment (IAT) is considered to be an effective strategy for removing the obstructing clot. Because outcome crucially depends on time to treatment ('time-is-brain' concept), we assessed the effects of an intervention based on performing all the time-sensitive diagnostic and therapeutic procedures at a single location on the delay before intra-arterial stroke treatment. Methods: Consecutive acute stroke patients with large vessel occlusion who obtained IAT were evaluated before and after implementation (April 26, 2010) of an intervention focused on performing all the diagnostic and therapeutic measures at a single site ('stroke room'). Result: After implementation of the intervention, the median intervals between admission and first angiography series were significantly shorter for 174 intervention patients (102 min, interquartile range (IQR) 85-120 min) than for 81 control patients (117 min, IQR 89-150 min; p < 0.05), as were the intervals between admission and clot removal or end of angiography (152 min, IQR 123-185 min vs. 190 min, IQR 163-227 min; p < 0.001). However, no significant differences in clinical outcome were observed. Conclusion: This study shows for the, to our knowledge, first time that for patients with acute ischemic stroke, stroke diagnosis and treatment at a single location ('stroke room') saves crucial time until IAT.
    No preview · Article · Oct 2015 · Cerebrovascular Diseases
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    ABSTRACT: Background: Recently, a strategy for treating stroke directly at the emergency site was developed. It was based on the use of an ambulance equipped with a scanner, a point-of-care laboratory, and telemedicine capabilities (Mobile Stroke Unit). Despite demonstrating a marked reduction in the delay to thrombolysis, this strategy is criticized because of potentially unacceptable costs. Methods: We related the incremental direct costs of prehospital stroke treatment based on data of the first trial on this concept to one year direct cost savings taken from published research results. Key parameters were configuration of emergency medical service personnel, operating distance, and population density. Model parameters were varied to cover 5 different relevant emergency medical service scenarios. Additionally, the effects of operating distance and population density on benefit-cost ratios were analyzed. Results: Benefits of the concept of prehospital stroke treatment outweighed its costs with a benefit-cost ratio of 1.96 in the baseline experimental setting. The benefit-cost ratio markedly increased with the reduction of the staff and with higher population density. Maximum benefit-cost ratios between 2.16 and 6.85 were identified at optimum operating distances in a range between 43.01 and 64.88 km (26.88 and 40.55 miles). Our model implies that in different scenarios the Mobile Stroke Unit strategy is cost-efficient starting from an operating distance of 15.98 km (9.99 miles) or from a population density of 79 inhabitants per km2 (202 inhabitants per square mile). Conclusion: This study indicates that based on a one-year benefit-cost analysis that prehospital treatment of acute stroke is highly cost-effective across a wide range of possible scenarios. It is the highest when the staff size of the Mobile Stroke Unit can be reduced, for example, by the use of telemedical support from hospital experts. Although efficiency is positively related to population density, benefit-cost ratios can be greater than 1 even in rural settings.
    Full-text · Article · Dec 2014 · Cerebrovascular Diseases
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    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.
    No preview · Article · Apr 2014 · International Journal of Stroke
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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.
    No preview · Article · Nov 2013 · Der Nervenarzt

  • No preview · Article · Oct 2013 · Journal of the Neurological Sciences
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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.
    No preview · Article · Jun 2013 · The Lancet Neurology
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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).
    Preview · Article · Mar 2013 · JACC. Cardiovascular Interventions
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    Preview · Article · Jul 2012 · Journal of the American College of Cardiology
  • S. Walter · P. Kostopoulos · A. Haass

    No preview · Article · Jun 2012 · The Lancet Neurology
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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.
    Full-text · Article · May 2012 · Neurology
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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.
    Full-text · Article · Apr 2012 · The Lancet Neurology
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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.
    Full-text · Article · Nov 2011 · Journal of the American College of Cardiology
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    ABSTRACT: [This corrects the article on p. e13758 in vol. 5.].
    Full-text · Article · Mar 2011 · PLoS ONE
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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.
    No preview · Article · Mar 2011 · Annals of Neurology

  • No preview · Article · Mar 2011
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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.
    No preview · Article · Dec 2010 · Journal of Neurointerventional Surgery

  • No preview · Article · Nov 2010 · Journal of Neurointerventional Surgery
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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.
    No preview · Article · Nov 2010 · Stroke
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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.
    Full-text · Article · Oct 2010 · PLoS ONE
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    ABSTRACT: Cervical artery dissection (CAD) accounts for 10-20% of all strokes in young adults, but no randomised controlled trial has investigated the best secondary prevention after ischaemic stroke or transient ischaemic attack (TIA). Because only small numbers of patient with CAD have been prospectively documented and followed up, the authors aimed to investigate the prognosis under various prevention regimens. 30 German departments of neurology with acute stroke units prospectively documented 250 patients with acute ischaemic stroke or TIA due to CAD. A central follow-up (median 31 months) assessed recurrent stroke, recurrent CAD and death in 198 patients. CAD was found more often in the carotid arteries (52.0%) than in the vertebral arteries (46.8%). Thirteen patients (5.2%, CI 3.1% to 8.6%) suffered a recurrent stroke during the acute hospital stay. The rate of recurrent CAD during the first year was 1.7% (95% CI 0.3% to 3.6%). The cumulative recurrent stroke rate during the first year was 10.7% (95% CI 6.5% to 14.9%) and 14.0% (95% CI 8.9% to 19.1%) over 3 years. After discharge, the rate of recurrent stroke up to 6 months in patients treated with anticoagulants was 2.0% (95% CI 0.6% to 7.1%) and in those treated with antiplatelets 16.7% (95% CI 5.8% to 39.2%), which was statistically significant (HR 0.11; CI 0.02 to 0.69, p=0.02). This observational study confirms a high risk of early recurrent stroke following acute IS or TIA due to CAD. Whether anticoagulation provides any benefit over antiplatelets needs to be investigated in a randomised controlled trial.
    Full-text · Article · Aug 2010 · Journal of neurology, neurosurgery, and psychiatry

Publication Stats

735 Citations
219.46 Total Impact Points

Institutions

  • 2008-2014
    • Universität des Saarlandes
      • Klinik für Diagnostische und Interventionelle Neuroradiologie
      Saarbrücken, Saarland, Germany
  • 2009
    • Oxford University Hospitals NHS Trust
      Oxford, England, United Kingdom
  • 2006-2009
    • Universitätsklinikum des Saarlandes
      Homburg, Saarland, Germany