Felix Schlachetzki

Bezirksklinikum Regensburg, Ratisbon, Bavaria, Germany

Are you Felix Schlachetzki?

Claim your profile

Publications (89)328.7 Total impact

  • Journal of neuroimaging: official journal of the American Society of Neuroimaging 09/2014; · 3.36 Impact Factor
  • Circulation 07/2014; 130(4):348-9. · 15.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Ocular color-coded duplex sonography (OCCS), when performed within the safety limits of diagnostic ultrasonography, is an easy noninvasive technique with high potential for diagnosis and therapy in diseases with raised intracranial pressure and vascular diseases affecting the eye. Despite the capabilities of modern ultrasound systems and its scientific validation, OCCS has not gained widespread use in neurological practice. In this review, the authors describe the technique and main parameter settings of OCCS systems to reduce potential risks as thermal or cavitational effects for sensitive orbital structures. Applications of OCCS are the determination of intracranial pressure in emergency medicine, and follow-up evaluations of idiopathic intracranial hypertension and ventricular shunting by measuring the optic nerve sheath diameter. A diameter of 5.7 - 6.0 mm corresponds well with symptomatically increased intracranial pressure (> 20 cmH2O). OCCS also helps to discriminate between different etiologies of central retinal artery occlusion - by visualization of a "spot sign" and Doppler flow analysis of the central retinal artery - and aids the differential diagnosis of papilledema. At the end perspectives are illustrated that combine established ultrasound methods such as transcranial color-coded sonography with OCCS.
    Ultraschall in der Medizin 03/2014; · 4.12 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND AND PURPOSECentral retinal artery occlusion (CRAO) is most often indirectly diagnosed by lack of retinal perfusion. Direct embolus characterization may help to understand the natural course and low response to treatment. In a previous study we identified a hyperechoic signal within the optic nerve and in the central retinal artery (“spot sign”).METHODS In this study we performed a follow-up investigation in 7 patients with CRAO and positive spot sign indicating the embolic cause of the occlusion after a median interval of 17 months (range 11-38 months) using a battery of tests (ocular color-coded sonography, optic coherence tomography [OCT], fundoscopy, amongst others).RESULTSThe spot sign persisted in all patients, none had high-grade internal carotid artery stenosis, stroke or transient ischemic attacks. Four patients were completely blind, 3 patients were able to recognize hand movements. OCT demonstrated retinal atrophy, and fundoscopy revealed only minimal arterial perfusion.CONCLUSIONS The hyperechoic spot sign may be an important predictive prognostic marker for persistent loss of vision. Its persistence may indicate calcified or cholesterol emboli and may explain the low therapeutic success rate to thrombolysis. Further studies on their origin and significance in atherosclerotic disease are warranted.
    Journal of neuroimaging: official journal of the American Society of Neuroimaging 03/2014; · 3.36 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Transcranial color-coded sonography (TCCS) has proved to be a fast and reliable tool for the detection of middle cerebral artery (MCA) occlusions in a hospital setting. In this feasibility study on prehospital sonography, our aim was to investigate the accuracy of TCCS for neurovascular emergency diagnostics when performed in a prehospital setting using mobile ultrasound equipment as part of a neurological examination. Following a '911 stroke code' call, stroke neurologists experienced in TCCS rendezvoused with the paramedic team. In patients with suspected stroke, TCCS examination including ultrasound contrast agents was performed. Results were compared with neurovascular imaging (CTA, MRA) and the final discharge diagnosis from standard patient-centered stroke care. We enrolled '232 stroke code' patients with follow-up data available in 102 patients with complete TCCS examination. A diagnosis of ischemic stroke was made in 73 cases; 29 patients were identified as 'stroke mimics'. MCA occlusion was diagnosed in ten patients, while internal carotid artery (ICA) occlusion/high-grade stenosis leading to reversal of anterior cerebral artery flow was diagnosed in four patients. The initial working diagnosis 'any stroke' showed a sensitivity of 94% and a specificity of 48%. 'Major MCA or ICA stroke' diagnosed by mobile ultrasound showed an overall sensitivity of 78% and specificity of 98%. The study demonstrates the feasibility and high diagnostic accuracy of emergency transcranial ultrasound assessment combined with neurological examinations for major ischemic stroke. Future combination with telemedical support, point-of-care analysis of blood serum markers, and probability algorithms of prehospital stroke diagnosis including ultrasound may help to speed up stroke treatment.
    Critical ultrasound journal 02/2014; 6(1):3.
  • Ulrich Bogdahn, Felix Schlachetzki, Gerhard Schuierer
    Stroke 08/2013; · 6.16 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: INTRODUCTION: Moyamoya disease (MMD) is an extremely rare neurovascular disorder in Caucasian children. To the best of our knowledge, the aggressive variant including hemorrhagic malignant stroke and consecutive global ischemia has not been reported for this population before. CASE REPORT: We present the case of an 11-year-old girl with sudden neurological deterioration due to intracerebral hemorrhage with early irruption into the ventricular system. MMD with extensive neovascularization was diagnosed by means of computed tomography and magnetic resonance imaging. Despite immediate ventricular drainage, intracranial pressure increased above the mean arterial pressure resulting in malignant bi-hemispheric ischemia. The girl died within 53 h after admission to hospital. DISCUSSION: Intracerebral hemorrhage in young patients is often attributed to vascular malformation. This case shows that MMD may constitute a potential diagnosis in the case of sudden neurological deterioration and loss of consciousness, even in previously healthy children.
    Child s Nervous System 04/2013; · 1.24 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Stroke is the second common cause of death and the primary cause of early invalidity worldwide. Different from other diseases is the time sensitivity related to stroke. In case of an ischemic event occluding a brain artery, 2000000 neurons die every minute. Stroke diagnosis and treatment should be initiated at the earliest time point possible, preferably at the site or during patient transport. Portable ultrasound has been used for prehospital diagnosis for applications other than stroke, and its acceptance as a valuable diagnostic tool "in the field" is growing. The intrahospital use of transcranial ultrasound for stroke diagnosis has been described extensively in the literature. Beyond its diagnostic use, first clinical trials as well as numerous preclinical work demonstrate that ultrasound can be used to accelerate clot lysis (sonothrombolysis) in presence as well as in absence of tissue plasminogen activator. Hence, the use of transcranial ultrasound for diagnosis and possibly treatment of stroke bares the potential to add to current stroke care paradigms significantly. The purpose of this concept article is to describe the opportunities presented by recent advances in transcranial ultrasound to diagnose and potentially treat large vessel embolic stroke in the prehospital environment.
    The American journal of emergency medicine 02/2013; · 1.54 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The 'new penumbra' concept imbues the transition between injury and repair at the neurovascular unit with profound implications for selecting the appropriate type and timing of neuroprotective interventions. In this conceptual study, we investigated the protective effects of pigment epithelium-derived factor (PEDF) and compared them with the properties of epidermal growth factor (EGF) in a rat model of ischemia-reperfusion injury. We initiated a delayed intervention 3 hours after reperfusion using equimolar amounts of PEDF and EGF. These agents were then administered intravenously for 4 hours following reperfusion after 1 hour of focal ischemia. Magnetic resonance imaging indices were characterized, and imaging was performed at multiple time points post reperfusion. PEDF and EGF reduced lesion volumes at all time points as observed on T(2)-weighted images (T(2)-LVs). In addition PEDF selectively attenuated lesion volume expansion at 48 hours after reperfusion and persistently modulated blood-brain barrier (BBB) permeability at all time points. Intervention with peptides is suspected to cause edema formation at distant regions. The observed T(2)-LV reduction and BBB modulation by these trophic factors is probably mediated through a number of diverse mechanisms. A thorough evaluation of neurotrophins is still necessary to determine their time-dependent contributions against injury and their modulatory effects on repair after stroke.Journal of Cerebral Blood Flow & Metabolism advance online publication, 9 January 2013; doi:10.1038/jcbfm.2012.201.
    Journal of cerebral blood flow and metabolism: official journal of the International Society of Cerebral Blood Flow and Metabolism 01/2013; · 5.46 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Patient: Female, 78 Final Diagnosis: Cerebral hyperperfusion syndrome Symptoms: - Medication: - Clinical Procedure: Endovascular embolectomy Specialty: Neurology. Unknown ethiology. Cerebral hyperperfusion syndrome (cHS) is a well known but rare complication after carotid endarterectomy, carotid angioplasty with stenting, and stenting of intracranial arterial stenosis. The clinical presentation may vary from acute onset of focal oedema (stroke-like presentation) and intracerbral hemorrhage to delayed (>24h hours after the procedure) presentation with seizures, focal motor weakness, or late intracerebral hemorrhage. The incidence of cHS after carotid endarterectomy ranges from 0-3% and defined as an increase of the ipsilateral cerebral blood flow up to 40% over baseline in ultrasound. We present a case of a 78-year-old woman with an acute ischemic stroke due to left side middle cerebral artery territory with right sided hemiparesis and aphasia (NIHSS 16). After systemic thrombolysis embolectomy using a retractable stent (Solitaire(®) device) was performed and resulted in complete and successful recanalization of MCA including its branches about 210 minutes after symptom onset but, partial dislocation of thrombotic material into the anterior cerebral artery (ACA). Cerebral hyperperfusion syndrome should be considered in patients with clinical deterioration after successful recanalisation and the early diagnosis and treatment may be important for neurological outcome after endovascular embolectomy.
    The American journal of case reports. 01/2013; 14:513-7.
  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: This article gives an up-to-date overview of neurosonographic emergency and intensive care diagnostics. METHODS: Selective literature research from 1984 with critical appraisal and including national and international guidelines. RESULTS: Fast and valid diagnostics in acute stroke is the main field of application of neurosonography. Specific monitoring methods bear great advantages for intensive care patients, especially "as-often-as-wanted" repetitive imaging under real-time conditions. A number of new developments make neurosonography an interesting area of research. CONCLUSIONS: Neurosonography has played a key role in neurological emergency and intensive care medicine for many years. It remains important to continuously support dissemination of the method.
    Medizinische Klinik, Intensivmedizin und Notfallmedizin. 10/2012;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: Sudden retinal blindness is a common complication of temporal arteritis (TA). Another common cause is embolic occlusion of the central retinal artery (CRA). The aim of this prospective study was to examine the diagnostic value of hyperechoic material in the CRA for the exclusion of vasculitis as a cause. The authors used orbital color-coded sonography (OCCS) for the detection of hyperechoic material. Materials and Methods: 24 patients with sudden vision loss were included in the study after the exclusion of other causes (e. g. vitreous bleeding, retinal detachment). Parallel to routine diagnostic workup, OCCS was performed in all patients. Results: 7 patients with a diagnosis of TA presented with different degrees of hypoperfusion in the CRA without hyperechoic material (referred to as "spot sign") detected by OCCS. Diagnostic workup in the remaining 17 patients revealed other causes of sudden vision loss, such as central retinal artery occlusion (CRAO) (12), anterior ischemic optic neuropathy (AION) (2), upstream vascular stenosis or occlusion (2) and delayed reperfusion of the CRA (1). The hyperechoic "spot sign" was visible in 10 of 12 patients (83 %) with embolic CRAO. The detection of embolic CRAO using the "spot sign" had a sensitivity of 83 % and a specificity of 100 %. The missing "spot sign" in patients with TA was a highly specific finding (p-value 0.01). Conclusion: The detection of the "spot sign" specifically minimizes the probability of TA as a reason for sudden blindness.
    Ultraschall in der Medizin 09/2012; · 4.12 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Transcranial B-mode sonography is an easy to use bedside imaging modality to monitor significant changes of the brain parenchyma such as in malignant middle cerebral infarction or intracerebral hemorrhage. The elevation of intracranial pressure can be followed with various neurosonographical techniques: Measurements of the ventricular width, midline shift, arterial resistance, and optic nerve sheath diameter. They should be viewed as complementary to each other and to other imaging modalities. Repeated cCT and MRI may be avoided in unstable patients by bedside neurosonography in the hands of an experienced physician. Monitoring of evolving hydrocephalus using serial measurements of the third and lateral ventricles can be used to guide therapeutic decisions such as the removal of a ventricular drainage. The cessation of cerebral blood flow in the case of intracranial pressure exceeding systemic arterial pressure is an important part of brain death diagnostics. Early demonstration of a sufficient temporal bone window is needed in patients in whom brain death may be expected. Cerebrovascular autoregulation is an integer component of the brain's blood supply and is compromised in a variety of neurological diseases. In neurological/neurosurgical patients in the intensive care unit, its assessment allows for extended neuromonitoring and control of therapeutic procedures.
    Ultraschall in der Medizin 08/2012; 33(4):320-31; quiz 332-6. · 4.12 Impact Factor
  • Ultraschall in der Medizin 06/2012; 33(3):218-32; quiz 233-5. · 4.12 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This study characterized artificially ventilated patients in a neurological intensive care unit (NICU) between 2006-2008 in a purely neurological clinic and a so-called stand-alone situation. In addition the long-term prognoses as well as the quality of life of surviving patients were investigated. All ventilated patients from October 2006 to December 2008 were enrolled in this descriptive, retrospective study. The duration of stay in intensive care was analyzed and the current quality of life was prospectively assessed based on the patient records. Final diagnoses, duration of intensive care unit and ventilation as well as the highest score in SAPS II (simplified acute physiology score) and complications during hospitalization were determined. The patients were divided into groups based on the diagnoses as vascular, inflammatory, neurodegenerative, hereditary, epileptogenic and others. Additionally patients were contacted and asked to respond by completing questionnaires on the Barthel index (BI) and the modified Rankin scale (mRS). During the study period a total of 512 patients were treated in the NICU of whom 201 required artificial respiration. Cerebrovascular diseases were the main reason for therapy in the NICU in 96 out of 201 cases (47.8%), followed by inflammatory diseases in 46 (22.8%) and epileptogenic diseases in 26 patients (13%). The median duration of artificial respiration was 9 days with a mean treatment duration of 16 days (range 1-57 days). Of the patients 31 (15.4%) died in the NICU and an additional 32 patients (18.8%) died within a median of 2 months after discharge. Outcome data were available from 67 out of 170 sent questionnaires and rehabilitation reports of 86 patients, which enabled the outcome of 121 surviving patients to be analyzed (71.2%). Of these 42.2% showed no or mild impairment in everyday life. However, the remaining 38% had severe impairments according to the BI. The evaluation of the mRS showed that 49.6% of the patients still had severe symptoms. More than one third of the patients treated in the NICU required artificial ventilation with an emphasis on cerebrovascular diseases, which illustrates the overlap between stroke unit and NICU care. Despite a lengthy duration of ventilation and a long stay in the intensive care unit more than one third of surviving patients showed no or only mild impairment. However, an additional third suffered from severe disability up to nursing care dependency. The study data differ little from the few publications in this field despite the stand alone situation of the NICU. The case mix index per day averaged around 0.3 and underlines the economic importance with respect to other forms of neurological treatment.
    Der Nervenarzt 06/2012; 83(6):741-50. · 0.80 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Rapid reperfusion following ischemia is the most effective therapy in stroke therapy. However, the success may be compromised by ischemia & reperfusion (I/R) injury and at the human blood-brain barrier (BBB), therefore the effects on transendothelial transport are of special interest. Current studies suggest the ATP-binding cassette (ABC) transporters to be regulated upon ischemic stroke in a way that impedes the effects of drug therapy. The immortalised human brain microvascular endothelial cell line hCMEC/D3 provides most of the unique properties of the BBB with respect to transport and might be a reliable in vitro model to study transendothelial transport after I/R. We exposed hCMEC/D3 cells to 24 hours of hypoxia alone and to hypoxia followed by 60 min of reoxygenisation as an in vitro model for I/R. Western blot showed mild upregulation of hypoxia inducible factor (HIF-1α) after hypoxia alone and RNA lysates were analysed with a well-established real-time RT-PCR-based TaqMan low-density array detecting 47 of 48 known human ABC transporters. No significant increases of ABC mRNA expression levels were detected neither in hypoxic nor in I/R samples. However, slight decrease of ABCC1 in hypoxic and I/R samples and of ABCA10 and ABCD3 in I/R samples was observed. Our data suggests that hCMEC/D3 cell line and - at the moment - in vitro models in general are a poor basis for stroke research but may be enhanced by co-culturing more cells of the neurovascular unit inducing an overall ischemic response at the BBB.
    Experimental and Translational Stroke Medicine 05/2012; 4(1):9.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Plasminogen activator inhibitor 1 (PAI-1) is the main inhibitor of tissue-type and urokinase-type plasminogen activator. A 4G/5G polymorphism in the promoter region of the PAI-1 gene has been reported to enhance the plasma levels of PAI-1. In particular, the 4G allele (guanosine deletion) has been linked with increased plasma PAI-1 levels, which may lead to impaired activity of the fibrinolytic system, thus increasing the incidence of thrombotic events. The aim of this case-control study was to analyze whether variants of the PAI-1 promotor genotype 4G/4G, 4G/5G and 5G/5G, in particular the 4G/5G-variant, constitute an independent risk factor of cerebral venous thrombosis (CVT). A total of 136 consecutive patients with proven CVT were compared to 1,054 DNA specimens of healthy controls from a population-based cohort. PAI-1 promotor polymorphisms were evaluated using polymerase chain reaction. No significant association of CVT with PAI-1 4G/5G was found in either the additive (OR 1.04; 95 % CI 0.78-1.38) or in the dominant model (OR 1.24; 95 % CI 0.72-2.13). Also, the prevalence of the other genotypes (4G/4G and 5G/5G) in patients was not significantly different from controls. When considering the variants of the PAI-1 promoter genotype in combination with known genetical thrombophilias, no differences were found either. As was expected, the prothrombin (G20210A) genotype was confirmed as an independent risk factor for CVT. We conclude that the 4G allele of the PAI-1 polymorphism does not increase the risk of CVT in adults.
    Journal of Neurology 04/2012; · 3.58 Impact Factor
  • Source
    Michael Ertl, Maria-Andreea Gamulescu, Felix Schlachetzki
    02/2012; , ISBN: 978-953-307-947-9
  • [Show abstract] [Hide abstract]
    ABSTRACT: The primary aim of this study was to investigate the diagnostic accuracy and time frames for neurological and transcranial color-coded sonography (TCCS) assessments in a prehospital '911' emergency stroke situation by using portable duplex ultrasound devices to visualize the bilateral middle cerebral arteries (MCAs). This study was conducted between May 2010 and January 2011. Patients who had sustained strokes in the city of Regensburg and the surrounding area in Bavaria, Germany, were enrolled in the study. After a '911 stroke code' call had been dispatched, stroke neurologists with expertise in ultrasonography rendezvoused with the paramedic team at the site of the emergency. After a brief neurological assessment had been completed, the patients underwent TCCS with optional administration of an ultrasound contrast agent in cases of insufficient temporal bone windows or if the agent had acute therapeutic relevance. The ultrasound studies were performed at the site of the emergency or in the ambulance during patient transport to the admitting hospital. Relevant timelines, such as the time from the stroke alarm to patient arrival at the hospital and the duration of the TCCS, were documented, and positive and negative predictive values for the diagnosis of major MCA occlusion were assessed. A total of 113 patients were enrolled in the study. MCA occlusion was diagnosed in 10 patients. In 9 of these 10 patients, MCA occlusion could be visualized using contrast-enhanced or non-contrast-enhanced TCCS during patient transport and was later confirmed using computed tomography or magnetic resonance angiography. One MCA occlusion was missed by TCCS and 1 atypical hemorrhage was misdiagnosed. Overall, the sensitivity of a 'field diagnosis' of MCA occlusion was 90% [95% confidence interval (CI) 55.5-99.75%] and the specificity was 98% (95% CI 92.89-99.97%). The positive predictive value was 90% (95% CI 55.5-99.75%) and the negative predictive value was 98% (95% CI 92.89-99.97%). The mean time (standard deviation) from ambulance dispatch to arrival at the patient was 12.3 min (7.09); the mean time for the TCCS examination was 5.6 min (2.2); and the overall mean transport time to the hospital was 53 min (18). Prehospital diagnosis of MCA occlusion in stroke patients is feasible using portable duplex ultrasonography with or without administration of a microbubble contrast agent. Prehospital neurological as well as transcranial vascular assessments during patient transport can be performed by a trained neurologist with high sensitivity and specificity, perhaps opening an additional therapeutic window for sonothrombolysis or neuroprotective strategies.
    Cerebrovascular Diseases 01/2012; 33(3):262-71. · 2.81 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Isoflurane is a popular volatile anesthetic agent used in humans as well as in experimental animal research. In previous animal studies of the blood-brain barrier (BBB), observations towards an increased permeability after exposure to isoflurane are reported. In this study we investigated the effect of a 2-hour isoflurane exposure on apoptosis of the cerebral endothelium following 24 hours of hypoxia in an in vitro BBB model using astrocyte-conditioned human umbilical vein endothelial cells (AC-HUVECs). Apoptosis of AC-HUVECs was investigated using light microscopy of the native culture for morphological changes, Western blot (WB) analysis of Bax and Bcl-2, and a TUNEL assay. Treatment of AC-HUVECs with isoflurane resulted in severe cellular morphological changes and a significant dose-dependent increase in DNA fragmentation, which was observed during the TUNEL assay analysis. WB analysis confirmed increases in pro-apoptotic Bax levels at 4 hours and 24 hours and decreases in anti-apoptotic Bcl-2 in a dose-dependent manner compared with the control group. These negative effects of isoflurane on the BBB after a hypoxic challenge need to be taken into account not only in experimental stroke research, but possibly also in clinical practice.
    PLoS ONE 01/2012; 7(6):e38260. · 3.53 Impact Factor

Publication Stats

822 Citations
328.70 Total Impact Points

Institutions

  • 2014
    • Bezirksklinikum Regensburg
      Ratisbon, Bavaria, Germany
  • 1997–2014
    • Universität Regensburg
      • • Lehrstuhl für Neurologie
      • • Department of Surgery
      • • Lehrstuhl für Anästhesiologie
      Ratisbon, Bavaria, Germany
  • 2009–2013
    • University Hospital Regensburg
      • Klinik und Poliklinik für Neurologie
      Regensburg, Bavaria, Germany
  • 2011
    • University of Minnesota Duluth
      • Department of Pharmacy Practice and Pharmaceutical Sciences
      Duluth, Minnesota, United States
  • 2008
    • Vilnius University Hospital Santariškių Klinikos
      Vil'nyus, Vilniaus Apskritis, Lithuania
    • Leibniz Universität Hannover
      Hanover, Lower Saxony, Germany
  • 2007
    • University Hospital RWTH Aachen
      • Department of Neurology
      Aachen, North Rhine-Westphalia, Germany
  • 2004
    • University of Rochester
      • Department of Biomedical Genetics
      Rochester, NY, United States
    • Nihon University
      • College of Pharmacy
      Tokyo, Tokyo-to, Japan
  • 2002–2004
    • University of California, Los Angeles
      • Department of Medicine
      Los Angeles, CA, United States
    • Children's Hospital Los Angeles
      • Division of Hospital Medicine
      Los Angeles, California, United States
  • 2000–2002
    • Justus-Liebig-Universität Gießen
      Gieben, Hesse, Germany